EP1098587A1

EP1098587A1 - Household robot for the automatic suction of dust from the floor surfaces

Info

Publication number: EP1098587A1
Application number: EP99948679A
Authority: EP
Inventors: Volker Sommer
Original assignee: Individual
Current assignee: Individual
Priority date: 1998-07-31
Filing date: 1999-07-22
Publication date: 2001-05-16
Also published as: US6370453B2; US20010004719A1; WO2000007492A1

Abstract

The present invention is used for the complete and fully automatic examination of floor surfaces of all kind as well as for a particularly efficient suction of dust therefrom since the lower areas, the edges and the recesses can be detected. In each case, the robot is controlled so as to explore the adjacent area and to detect the potential obstacles using special sensors before storing them in a data field. The displacement towards a new location is then carried out using the stored data until the whole accessible surface has been covered. One of the main constituent members of the robot consists of an extensible arm that rests on the robot and on which contact and range sensors are arranged. When the robot is used as an automatic vacuum cleaner, an air flow is forced into the robot arm and the cleaning effect can further be enhanced by providing one or more circular rotary brushes at the front end of the arm. This invention can essentially be used for domestic or industrial cleaning purposes with a view to replace traditional vacuum cleaners.

Description

description

Household robots for automatic vacuuming of floor surfaces

State of the art

Today's commercial household vacuum cleaners are fundamentally similar in function and handling to their predecessors from the beginning of the century, although continuous improvements have been achieved over the decades in the areas of suction power optimization, noise generation and air filtering. The different models on the market differ in addition to their design, essentially in the motor strength, which can be partially controlled electronically, the noise insulation and their filter quality.

The classic cylinder vacuum cleaner consists of an engine block mounted on rollers, to which various nozzle shapes can be connected via a hose. For vacuuming floors, a rigid nozzle shape attached to a telescopic handle is generally used for this purpose, which enables the vacuuming of an approximately 20 cm wide strip. Alternatively, the engine block can also be integrated in the telescopic handle. For smooth floors, a short brush is integrated in most models, which can be pushed out of the nozzle using a pedal or hand switch. In addition, a nozzle with a horizontally rotating brush can be used on some models to increase the cleaning effect (tapping). This brush is driven either electrically or indirectly via the air flow.

In order to increase the cleaning effect, especially for use in sweepers, an arrangement of several disc brushes which are set in multiple rotation by means of a planetary gear is described in the German patent specification 1057154. Also known from sweepers are two permanently installed plate brushes at the front two corners, which the automatic vacuum cleaner in DE 43 07 125 A1 has, in order to convey dirt in the immediate side region of the vacuum cleaner in front of a rigidly installed suction nozzle. In the German patent application DE-OS 21 01 659 a vacuum cleaner with a telescopically extendable suction arm, which has a circular cross-section, is described, at the end of which the suction nozzle is attached. The suction cup is not mobile, but can only rotate in a certain angular range using a cross-mounted steering wheel. Sensors are not available, only the sides of the suction nozzle are rotatably supported by a spring mechanism in order to avoid obstacles.

British Patent GB 20 38 615 A shows a remote-controlled vacuum cleaner with a circular base on three wheels, two of which are driven, in which the rigid suction nozzle is attached below the base of the vacuum cleaner. However, a control method and sensors are not specified.

The patent US 50 95 577 describes a self-propelled vacuum cleaner, in which the suction nozzle is attached to the end of a suction hose rolled up on a drum and can be extended with it. Thanks to mechanical sensors and control elements, this device is able to follow the course of a wall and thereby retract and extend the suction nozzle.

The same mechanism, but for extending one or two suction nozzles transverse to the direction of travel, is shown in US Pat. No. 5,199,996, although the vacuum cleaner is only moved on parallel and perpendicular tracks. Another control method for an automatic vacuum cleaner shows the patent DE 4340 771 A1. in which the suction cup is guided along the inner contour of a surface to be cleaned and thereby detects the contours of the surface to be cleaned. Then a microprocessor compares the layout of the room with previously saved contours to select the appropriate cleaning program. In addition to optical and ultrasound sensors on the top of the suction cup, a magnetic field sensor is used for orientation to determine the direction.

A similar control method is described in EP 01 42 594 B1 and DE 43 07 125 A1, but with the additional function that the vacuum cleaner independently plans and executes parallel cleaning tracks after a cycle to determine the contours of the surface to be cleaned, without a cleaning program beforehand would have to be stored for a specific room.

The published patent application DE 196 14 916 A1 describes an automatically operating driving robot, the orientation of which is essentially based on the stereoscopic one Evaluation of the image data from two video cameras is based. However, no specific tax procedure is specified.

In addition to the previously mentioned deterministic control methods, an independently operating vacuum cleaner was presented at the "DOMOTECHNICA 99" trade fair, which is essentially stochastically controlled. The vacuum cleaner moves in a certain direction until an obstacle is detected by sensors , blocks its path, the sucker then turns away from the obstacle and continues in any other direction until another obstacle forces it to change course, and so on.

Problem

Despite the optimization achieved in individual areas over the decades, vacuuming with the manual devices available today remains a time-consuming and strenuous housework, since frequent bending down, possibly moving objects and sometimes vigorously rubbing the suction nozzle are necessary. In addition, due to the inflexible floor suction nozzles, damage to sensitive furniture can occur, and that the suction nozzle must be manually switched each time to switch from smooth to carpeted surfaces in order to achieve optimum suction. If there are constrictions to be vacuumed, the suction nozzle must even be laboriously replaced. The known control methods for automatically operating vacuum cleaners have the following disadvantages:

Control methods that require manual guidance of the route are too complex and very inflexible, since the floor surface to be vacuumed changes constantly in the household due to the moving of objects. Control procedures that independently determine the outer contours of the surface to be vacuumed before the start of the actual suction process and determine their cleaning paths with this information are overwhelmed if many obstacles, such as e.g. B. furniture, to constant evasive maneuvers. In addition, due to the edge scanning, it takes a relatively long time for the actual suction process to begin and the method only works in closed room areas. About that- In addition, it is not possible to specify a specific starting point for the vacuum cleaner from which the cleaning process should start.

Purely stochastic control methods also work unsatisfactorily, since certain areas are very often covered, while other areas are rarely or not cleaned, which results in uneven cleaning. The suction process also takes a long time and there is no termination criterion.

The self-propelled vacuum cleaners controlled with the above procedure are not suitable as a replacement for manual vacuum cleaners for the following reasons:

Powerful vacuum cleaners have a bulky design and are therefore not suitable for use in confined spaces, also because damage to sensitive objects cannot be excluded. In addition to complex drives, numerous and complicated sensors are used, making the devices vulnerable and very expensive. Flat devices with a circular base have recently been developed to improve accessibility. However, this limits the possible battery size and thus the range and the suction power, and yet many areas in corners and niches as well as on furniture edges cannot be cleaned because they are not accessible to the vacuum cleaner.

The invention is therefore based on the object of providing a flexible control method which, on the one hand, is able to adapt itself automatically to any floor surface with any obstacles, and on the other hand to avoid unnecessary multiple cleaning of certain areas while other places are not or only insufficiently recorded. In addition, the cleaning should be able to start directly at a location specified by the user, without having to laboriously scan the room contours beforehand. In order to represent a serious alternative to conventional vacuum cleaners, the device controlled by the method should cover all floor areas and also furniture edges and narrow niches, a high cleaning effect being required and damage having to be excluded. The device must be made large enough to take up sufficient battery capacity. Appropriate insulation can largely shield the noise generated. The vacuum cleaner should continue to be as simple as possible, robust and avoid complicated sensors in order to enable cost-effective production. solution

To solve the problems mentioned, a fully automatic control method, in particular for a self-propelled vacuum cleaner with distance and contact sensors, is presented, which has the following essential features: a close range is defined around the device, which is scanned by sensors, and possible at the limits of the close range new positions saved for the device. After selecting one of the positions saved in the current or previous step, depending on the degree of accessibility, an assigned priority and taking into account the presence of an area that has not yet been scanned in the area of the possible new positions, the selected position is approached and then the described position The sequence of the process steps is repeated until a predetermined total area has been completely covered or no new position can be selected.

The floor area scanned by the sensors is mapped into a two-dimensional data field in order to mark obstacles, free areas and possible new positions for the device identified during the scanning by certain statuses. This field, in which an image of the accessible floor area with the contours of all obstacles and delimiting edges is gradually created, serves to define control parameters for the device and to control the area already covered.

Further advantageous refinements of the control method are given below:

The close range can be determined by the range of the sensors which are rigidly or movably attached to the device. Here, direction-sensitive sensors with long-distance effect can be used or simple contact or distance sensors, which are guided over the surface to be scanned by a suitable mechanism. However, the scanning of the close-up range can also be carried out in such a way that the effect of sensors with remote control or of movable sensors is emulated by moving the entire device and this determines the maximum accessible close-up range with any obstacles by sensors without remote control. In this case, any partial area relative to the position of the device can be defined as the near area. When using sensors that do not provide any direction information, the exact position of the obstacle is determined after the detection of an obstacle by taking the scanning direction into account.

In order to limit the number of stored positions, new positions will only be saved after scanning the close range where no obstacles have been detected and also no surface areas that have already been scanned from an earlier position of the device. This condition can be realized particularly simply by storing new positions only at those boundaries of the close range which are marked in the data field as not yet scanned.

When mapping a point (x, y) into the data field with the dimensions x_max and y nax, a transformation into a positive coordinate range takes place for negative coordinates, e.g. B. by forming x_max - | x | or y_max - | y |.

When a region already marked in the data field is scanned again, the statuses of this area are updated in accordance with the new sensor data. This ensures that due to the overlap of the scanning areas and in particular if obstacles are placed in areas already scanned, the stored information about the scanned area is always up to date.

When selecting a new position for the device, only those positions are taken into account which are not marked as already scanned in the data field. This criterion represents a simple but effective way to take into account the areas not yet scanned in the area of new positions: If a position has been marked as already scanned since it was saved in the data field, it can be assumed due to the generally compact near areas that the surrounding area has already been scanned. Such a position can therefore be deleted since it no longer has to be approached.

When storing new positions, different priorities can be assigned for these positions, depending on e.g. B. of their location and proximity to other positions. When selecting a new position for the device, only those positions are considered whose priority does not fall below that of a new position which has already been provisionally selected in the current method step. When selecting a new position, only those positions are taken into account that are in a specific partial area, and this partial area is modified during the course of the method if no new position can be selected within the current partial area. This method enables the movement of the device to be influenced indirectly, for example in order to ensure that the device primarily covers contiguous surface areas.

When selecting a possible new position, the distance and the direction from the current position can be taken into account as evaluation parameters.

In addition, when selecting a new position for the device, it can be ensured by evaluating the data field that the new position can be reached by the device directly, only areas which have already been scanned and not marked as an obstacle being allowed to be passed over.

It is also possible, when selecting a new position, to take into account the distance traveled since a possible new position was stored, in order to limit the influence of possible slippage. This can be done, for example, in that when checking the accessibility of a position in the data field, an additional safety distance at the edges of the route to be traveled, the width of which depends on the distance traveled, must be marked as free.

After selecting a new position by evaluating the data field, the shortest route within the area already scanned is determined by avoiding obstacles and the device is moved along this route.

The device can be reset to any previous positions and certain intermediate positions can be skipped when resetting the device over several previous positions if a check in the data field shows that the device does not have to pass over areas marked as obstacles during its movement.

If an unexpected obstacle blocks the movement of the device, it determines the contours of the obstacle by scanning the sensors. Since, during the movement of the device, there is generally no renewed scanning of the path - since only areas that are marked as free in the data field are passed over - the device can encounter obstacles unknown to it by moving objects or possibly by slipping. In this case, the loading movement of the device is aborted, the close range is scanned in order to update the stored environmental information, and then a new position is selected.

After approaching a new position, the new close range is determined by evaluating the data field so that there is only a slight overlap with neighboring areas that have already been scanned.

For the use of the invention as a vacuum cleaner, it is particularly advantageous if the floor surface is simultaneously cleaned during the scanning.

For this purpose, scanning can be carried out by means of a movable arm in such a way that areas which have not yet been scanned are always first swept over by the front end of the arm. If there is an obstacle contact, the arm is guided along the detected obstacles at the smallest possible distance. In a particularly advantageous manner, the near area around the device can be selected in the form of a circular sector, the scanning being carried out by repeated left and right rotation of the device, each with an increased length of the arm. In order to avoid multiple scanning of the same obstacles, the arm can be shortened accordingly in the angular ranges of obstacles that have already been detected.

By evaluating the information in the data field, it is ensured that the floor surface is only cleaned in those areas which are marked as not yet cleaned in the data field.

A device suitable for the method according to the invention which, of course, in addition to a suction device can also contain other cleaning devices, for example for wiping, steam cleaning or spray cleaning, or alternatively for other purposes such as, for. B. Lawn mowing, property search or control tasks can be combined, the following can be combined essential features:

The device with driven wheels and steering wheels or controllable drive wheels and sensors and an extendable arm is characterized in that in addition to two driven wheels as the third support point, the front lower end of the arm (head) is used, which z. B. is supported on rollers, balls, wheels or bristles.

The device with driven wheels and steering wheels or controllable drive wheels and sensors and an extendable arm with the front The end of the head is characterized in that one or more rotating plate brush (s) is / are arranged on the head.

The device with driven wheels and steering wheels or controllable drive wheels and sensors as well as an extendable arm is characterized in that distance or contact sensors for detecting obstacles are arranged on the arm, which move over the close range by moving the arm and rotating the device can and both detect obstacles to the movement of the arm and those which only represent an obstacle to the movement of the device. The device with driven wheels and steering wheels or controllable drive wheels and sensors is characterized in that the drives z. B. are connected elastically to the respective wheel via worm gears, the displacement of the drives which occurs when the suction device is blocked by an obstacle being detected. This mechanism makes it possible to dispense with an additional external contact sensor which would have to completely surround the device and which is mechanically complex.

Additional advantageous features of the device are described by the following features:

The plate brush (s) are driven by a sliding shaft by means of a gear motor that is attached to the base of the suction cup.

Each brush is surrounded by a dense ring of soft bristles that are slanted outwards to remove dust from furniture edges and prevent damage. In addition, each brush can have bristles that are inclined inwards, which loosen dirt from the floor, can support the suction device, and additionally borrowed the suction head at small steps, such as. B. Lift carpet edges.

If several disc brushes are used, their axes can be arranged and driven so that the brushes move the dirt in the direction of the suction nozzle below the head. An arrangement known per se is particularly advantageous here, see German patent 1057154, in which the brushes are set to self-rotation via a planetary gear and at the same time rotate in a circle below the head. Special sensors in the area of the head detect obstacles to the movement of the arm. A sensor for this purpose can advantageously be designed in such a way that two electrical conductors are attached ^"a short distance apart" around the head of the arm, of which the outer one is elastically pressed against the inner one in contact with an obstacle and thereby an electrical circuit closes.

Other sensors in the area of the head detect obstacles to the movement of the device, which, however, do not hinder the arm itself. For this purpose, a distance sensor, the z. B. by ultrasound or by means of electromagnetic waves, the clear height above the head is used. In addition, a sensor, e.g. B. in the form of a mechanical button or contactless, detect levels in the flooring below the head, so as to avoid tilting of the device. The movable arm is advantageously designed as a telescopic arm with a rectangular cross section, in order to offer a large cross section for guiding the air flow when used as a suction device with a flat design.

If the device is not supported on the front end of the extendable arm, it is advantageous to design the telescopic arm so that it is rotatably or vertically movable at its rear end in order to guarantee good ground contact of the head. In this case, too, an additional support with integrated ball for rolling can be attached below the front end of the arm, which allows any lateral movements.

The head pressure can be varied by shifting the weight.

After the blocking sensor has been triggered, the device is advantageously reset until the sensor no longer indicates a blocking. Subsequently, however, it is advanced again at a reduced speed in order to distinguish between pseudo and real obstacles. If the sensor has triggered for the first time due to a real obstacle, it will respond again even at a reduced speed. However, the cause was only an insurmountable step in the flooring, e.g. B. a carpet edge, or an increased frictional resistance of the brush, the lower speed causes a reduction in the dynamically acting forces and the frictional forces, so that there is no triggering again. Embodiment

The sequence of the method according to the invention is explained in more detail using a vacuum cleaner as an exemplary device, the structure of the device being described first for better understanding. The method according to the invention can of course be used independently of the device described here and also with any suitable devices.

The figures explain the exemplary embodiment of the invention described below, showing:

Fig. 1: View of the vacuum cleaner Fig. 2: View of the vacuum cleaner

Fig. 3: Longitudinal section of the suction head

Fig. 4: Top view of the suction head

Fig. 5: Drive with blocking sensor

Fig. 6: Path control for sector suction Fig. 7: Sector suction area with existing obstacles

Fig. 8: Line-up of sector suction areas

Fig. 9: Storage of the vacuumed areas

Fig. 10: Overall flow diagram of the suction control

Fig. 11: Flow chart 'suction of the sector in front' Fig. 12: Flow chart 'suction rotation with possible shortening of the arm'

Fig. 13: Flow chart 'arm extension with possible suction cup rotation'

Fig. 14: Flow chart 'Determination of a new suction cup position'

Mechanical construction

Drive and motion concept

Fig. 1 shows the view of the vacuum cleaner while Fig. 2 shows the view of the lowest level of the vacuum cleaner with the dust catcher removed.

It is driven by two stepper motors, each with a worm gear with a reduction ratio of approx. 1:30 a wheel with a rubber-coated tread drive. By arranging the impellers on the axis of symmetry of the circular base, both the propulsion (same direction of rotation) and the rotation around the center of the suction cup (opposite direction of rotation) can be achieved by means of the two motors. The suction brush, which is attached to the front end of the extendable suction arm, is used as the third support point.

Appropriate arrangement of the relatively heavy battery, which supplies both all the motors and the electronics with energy, on the base plate ensures that the suction device is slightly overweight, which ensures a stable support at all times. This concept results on the one hand in a very simple mechanical construction, since no additional support wheel is required, on the other hand, the suction brush always has a safe contact with the floor surface, regardless of unevenness in the floor covering.

Extendable suction arm with rotating brush

The extendable is an essential design element of the vacuum cleaner

Suction arm, see Fig. 1 and 2, which also gives access to hard-to-reach floor areas, e.g. B. under cupboards or in narrow niches.

The suction arm has a rectangular cross section and essentially consists of two telescopic hollow bodies made of plastic, through which the air flow is directed.

The length of the suction arm is also controlled by a stepper motor, which drives a rack attached to the extendable inner part at the front and allows exact positioning.

At the front end of the arm there is a rotating suction brush, which is set in rotation by a worm gear. The worm in turn is attached to a shaft with a square cross-section on which a bevel gear can slide momentarily. The bevel gear is axially fixed on the base plate of the suction cup by means of a corresponding bearing on the outer side and by a second bevel gear on the inside at an angle of 90 °. This arrangement ensures that the brush can be rotated independently of the current length of the suction arm. In addition, the suction arm can be constructed very flat to also clean the floor under low furniture. A commercially available gear motor is used as the drive for the brush, with which a rotational frequency of the brush of approx. 0.5 Hz is set. The cleaning effect is achieved in that the dust is directed into the collecting container via the brush within the suction arm by the air flow which is generated by means of an approx. 50 W electric motor.

The high suction power is due in part to the fact that the smooth-walled and streamlined air flow causes little turbulence and thus low losses.

An additional, decisive improvement in the cleaning effect is brought about by the suction brush rotating about its vertical central axis, the longitudinal section of which is shown in Fig. 3; the section line B-B 'can be seen in Fig. 4. This brush bundles the air flow and mechanically removes dust and other foreign objects from the floor, within wide limits regardless of the floor covering to be vacuumed.

The so-called brush wheel is connected via an axis to a gear wheel above the suction arm into which the worm, which is attached to the end of the rectangular shaft, engages. The brush wheel is designed as a spoked wheel in order to obstruct the air flow as little as possible. All bristles are attached to the outer edge of the brush wheel, the bristles inclined inwards to the axis being relatively stiff and having a sufficiently large mutual distance to allow the air flow to pass between them unhindered; these bristles support the suction cup to the front and cause the outwardly inclined, very soft bristles to just touch the floor covering. In addition to the resulting reduction in frictional resistance, there is an additional advantage in that the outer bristles are very tight and the air flow can only pass through the gap to the floor, which creates an effective radial nozzle effect.

For very soft floor coverings, an additional plastic support can be attached underneath the brush wheel, almost as an extension of its axis, to prevent the suction head from sinking too deep. A freely rotatable roller ball is integrated into this support towards the floor to minimize friction loss when the arm moves, see Fig. 3. The inwardly inclined stiff bristles have another important function, because they also enable a smooth transition when crossing small steps in the flooring, e.g. B. on carpet edges. At these, the outer soft bristles are pressed inwards when the suction arm moves, the suction head being slightly raised due to the elasticity of the bristles. This effect is greatly enhanced by the oblique arrangement of the inner support bristles, so that the suction arm can slide over the step.

The brush resistance when moving the vacuum cleaner on carpet or over steps is also significantly reduced by the vertical rotation of the brush. The rotational frequency must be adapted to the lateral speed of movement of the suction head in order to allow the suction head to roll optimally. Due to the radial asymmetry of the brush, this effect is independent of the current direction of movement of the vacuum cleaner.

Compared to conventional suction head and brush shapes, the construction presented here has a great advantage in that, especially in the direct outer environment of the suction head, e.g. when vacuuming on furniture edges and baseboards, a high cleaning effect is achieved, whereby damage is prevented by the soft outer bristles.

Overall, the interaction of all these factors ensures that, despite the motor power which is necessarily limited due to the battery supply, the suction effect is considerably better than in conventional vacuum cleaners with significantly higher electrical connection values.

Orientation of the suction cup using sensors

The orientation of the suction cup is based on the calculation of the current suction position based on the distance covered. Due to the exact step control as well as the statistical occurrence of any positioning errors, a location accuracy can be achieved which, even after long distances to be covered when vacuuming a room, is completely sufficient in conjunction with the sensors. To detect obstacles with a high spatial resolution, the suction head probes by the rotation of the suction cup and the corresponding arm extension in front of the suction cup lying floor surface, see chapter "Vacuuming a sector". The circular symmetry of the vacuum ensures that only the vacuum head can hit obstacles during rotation.

In total, three sensors are required for this task: The most important function is the mechanical touch sensor on the suction head, the structure of which can be seen in Fig. 4. This sensor is used to detect the impingement of obstacles when the arm is rotated and moved longitudinally.

It essentially consists of two plastic strips that surround the suction head and are held at a mutual distance of a few millimeters by two side spacers. While the inner strip is firmly connected to the suction head, the outer strip is only held over the spacers and is made of very thin, elastic plastic in order to achieve a soft spring effect.

The mutually facing inner sides of both strips are coated with a conductive material and connected to the electronics via connecting wires. In the normal state, these surfaces, which act as contacts, are electrically insulated from one another by the insulating spacers and the air. However, if the suction head encounters an obstacle, the outer strip is pressed against the inner one, so that the electrical circuit closes; the direction from which the obstacle hits is insignificant.

The two beads on both sides of the suction head are used in order to be able to reliably detect precisely lateral contact when the suction device rotates. These beads transfer lateral pressure to the outer elastic strip, which is then pressed against the inner strip. Fig. 1 shows that the touch sensor encompasses the entire height of the suction head and is also guided far downward in order to detect possible obstacles which can block the movement of the suction head.

Although the touch sensor is not able to determine the direction in which an obstacle lies directly, this information can always be obtained by knowing the direction of movement of the suction head.

The second very important sensor is the so-called height sensor on the upper, front edge of the suction head, see Fig. 3 and 4. This sensor has the task be able to detect obstacles that do not hinder the suction arm and head, but whose clear height is not sufficient for the entire suction device to pass this point.

A commercially available infrared distance sensor is used for this purpose, the release distance of which is set exactly to the height of the suction cup minus the suction head height. This sensor has a high lateral accuracy, so that a lateral spatial resolution of a few centimeters is achieved even with obstacles at a vertical distance of approx. 30 cm.

A so-called step sensor is provided as the third sensor, see Fig. 3, for larger displacements of the floor covering e.g. B. on stairs and thereby prevent the vacuum cleaner from tipping over.

This sensor consists of a sensitive button, which is attached just behind the suction head to the lower edge of the suction arm, whereby the sensor is at a distance of approx. 1 cm from the floor on flat surfaces. If the suction head is moved down a step with a vertical offset that corresponds at least to the distance of the sensor from the floor, the suction arm touches the button, which triggers the sensor.

The sensors described so far are sufficient to be able to clearly maneuver the suction device in the normal case by means of the method described in the section "automatic control of the suction device".

Nevertheless, moving objects into areas that have already been vacuumed cannot rule out that the vacuum cleaner encounters obstacles during its movement.

In order to be able to indicate an obstacle to the control program in this case as well, the power transmission from the stepper motors to the two drive wheels is each equipped with a mechanical blocking sensor.

In order to clarify the function of the blocking sensor, one of the two drives is shown in detail in Fig. 5, see section line AA 'in Fig. 2: The pinion of the stepper motor transmits its moment to a toothed wheel, which in turn drives a worm gear. The shaft on which the gear wheel and the worm are fastened is connected to the drive bracket by axle rings, so that no axial displacement of the shaft against the bracket is possible and therefore the rotation hung the drive shaft is transmitted by the worm gear in the rotation of the impeller.

However, this drive unit does not act as a rigid system, since the common mounting of the shaft and the stepper motor consists of elastic material, which allows slight axial displacements of the drive shaft if the suction device jams during motor rotation.

According to Fig. 5, this shifting of the bearing closes an electrical contact, which is evaluated by the control electronics.

The implementation of a blocking sensor presented has the advantage over rigid systems that when a sudden blockage of the suction cup occurs, no large forces act which may lead to damage, but that, due to the elasticity of the bearing, a gradual increase in the driving force on the shaft sets in until the blocking sensor trips.

By changing the stiffness of the bearing, the elasticity of the drive can be individually adapted to the weight of the suction cup and the dynamically acting forces.

Automatic control of the vacuum

Presentation of the tax principle

The vacuum is controlled in such a way that, starting from the current location and in relation to the previous direction of rotation, a sector of maximum 90 ° is meandered, see Fig. 6: First, the vacuum rotates to the left maximum position. Then there is a maximum rotation to the right, an extension of the suction arm by the suction head diameter, and then a return rotation to the left maximum position. This movement process is repeated until the suction arm has reached its final length, whereupon, after the last rotation to the right, it is completely withdrawn.

The described motion control is automatically adjusted if there are obstacles during the rotation or arm movement, see section "Sucking a sector". Fig. 7 shows a restricted sector area, which is from Suction head can be painted over if objects hinder the movement. This can create so-called suction shadows that the suction head cannot reach by blocking the rotation of the suction arm.

In addition to these suction shadows, other free marginal areas of the currently vacuumed sector are also marked, see the next section, and thus identified as potential new vacuum cleaner positions. From the totality of these positions, the next suction position is selected and approached after completion of the sector suction, see "Determining a New Suction Position".

Figure 8 uses the example of a corner of the room to show how, by lining up individual sector suction areas, areas of any type of border can be completely vacuumed (in this example, all sectors have the maximum opening angle of 180 °). By overlapping the sectors, some areas are vacuumed several times, which additionally increases the cleaning effect and compensates for possible positioning inaccuracies of the vacuum cleaner. To increase the range with one battery charge, the vacuum motor, which is the largest consumer, is only switched on during sector vacuuming and not when a new vacuum cleaner position is taken up.

Marking of the vacuumed areas

For global orientation of the vacuum cleaner, the entire surface to be vacuumed is mapped in an electronic data memory, the so-called suction field, and the various states that can be assigned to a surface element are marked therein. This two-dimensional information is used to identify new suction positions, to determine the way there and to determine the sector area.

The following four states are distinguished:

• Status 0: 'not sucked'

This status is the default value in the suction field at the start of the vacuum cleaner and is overwritten as soon as the suction head has passed the corresponding point for the first time. • Status 1: 'sucked'

All fields of the suction field that have already been swept by the suction head and that do not represent an obstacle to the movement of the suction device receive this status. • Status 2: 'obstacle'

This status is used to identify obstacles that have been detected by the sensors. A field with this status cannot be run over by the vacuum cleaner when it takes up a new suction position. • Status 3: 'Possible new suction position'

With this status, an edge field, which must previously have the status 0, is marked as a possible new suction position during the suction of a sector. If the area is later swept over by the suction head, the field receives status 1 or 2. When checking a possible new suction position, status 3 indicates that the corresponding area has not yet been vacuumed.

A two-dimensional grid is used to map the real surface to be sucked onto the suction field. The spatial resolution in the x and y directions corresponds to one centimeter each and is therefore sufficiently precise for the detection accuracy of the sensors. Since only two bits are required for the four different statuses, it is possible with this resolution to map an area of 10x10 m ² into a memory area of only 250 kByte.

A possible problem in minimizing the memory requirement arises from the fact that at the start of the suction process, the suction device is located at any point

Room is started. Starting from this origin, both positive and negative coordinate values can occur for x and y, whereby the latter cannot be adopted directly into the suction field. To solve this problem, a coordinate transformation is carried out, see Fig. 9: Each negative value for x or y is mapped to x _max - | x | or y _max - | y |, where ^x max ^{uncl Ymax} specify the maximum dimensions of the suction field for x and y that limit the range of motion of the suction cup. Through the transfor Field areas where at least one coordinate is negative are shown offset in the suction field.

During the motion control, it is monitored that the sum of the maximum positive and negative suction distance from the origin in the x and y directions does not exceed the specified values for x _max or y _max . Otherwise the program flow is interrupted with a corresponding error message. As the suction head moves almost continuously, new statuses are set in the suction field after a distance of 1 cm has been covered. In this case, the fields below the outer radius of the suction head are taken into account, semicircular with respect to the respective direction of movement of the head.

An exception to this marking rule applies to the height and level sensor: If these sensors report an obstacle, only the field in the suction field that is exactly below the corresponding sensor is marked.

Description of the tax process

In the flowcharts described below, the following notation is used for the display: Start and end or return to the previous diagram are indicated by circles. Rectangles each symbolize an action, while shaded symbols indicate that the corresponding action is detailed in a separate diagram. Hexagons with two side tips stand for a decision with the two options 'yes' or 'no'.

The overall flow diagram for the suction control is shown in Fig. 10.

At the beginning of the suction process and whenever a new suction position has been taken, the current suction position is saved. The x and y coordinates of the suction center, the length of the suction arm and the angle that the suction arm makes in relation to the x axis are required for clear localization.

The optimum size of the sector to be vacuumed is then determined within the maximum limits of the angle of ± 90 ° (based on the previous direction of the vacuum) and the maximum possible length of the vacuum arm R _maχ . For this purpose, a check is made in the suction field to determine which points still have status 0, ie unsucked, exhibit. The area in which these points lie is determined by the left and right limit angles W | and W _r as well as the outer and inner radius R _a and Rj, where Rj always corresponds to the constant arm length when retracted. In the next step, the determined sector area is vacuumed, see section "Vacuuming a sector", including appropriate obstacle treatment. All swept areas are marked with status 1 in the suction field or status 2 when an obstacle is detected.

Now, new suction head positions (tasks) are marked as possible starting points for new suction sectors on the free outer edges of the suction area, which are identified by status 0, with status 3 in the suction field. In addition to this marking, each task is saved with its coordinates, its priority and the new optimal suction direction (perpendicular to the respective edge) in the list of open tasks. If the vacuum cleaner moves to W | or W _{r could be} rotated and on the suction shadows behind obstacles, the corners are marked as possible new suction positions. In addition to the side edges, the center of each free edge area (marked by the fact that the arm could be extended to R _a without contact with obstacles) is marked. To increase the number of possible suction positions, additional edge points are marked and saved in larger free edge areas next to the center, but with the lower priority 2. In Fig. 6 the possible new suction positions for the case of a sector without and in Fig. 7 depicted with obstacles as black (priority 1) or white arrows (priority 2), the arrowheads indicating the new suction directions. The current suction head position from which the last sector was sucked is now deleted from the list of the still open tasks.

Then the suction position for the next sector suction is determined from the total of the stored tasks and the suction head is moved to this point, see section "Determination of the next suction position". If no new suction position could be determined and approached, the suction process is ended, otherwise continue with saving the new suction position as described initially. Sucking a sector

When the current sector is sucked, the limits of which were determined after moving to a new position, the path-optimized control of the suction head described below enables the contours of any objects to be precisely scanned, which hinder the movement of the suction arm.

If no obstacles are detected during sector vacuuming, the suction head moves as shown in Figure 6. However, if the suction head encounters an obstacle during rotation or changes in length, it is guided along this in close contact. In order to be able to guide the suction head around already known obstacles and thereby avoid double detection, the so-called angular field is used, which is reinitialized before each sector suction and serves to save the maximum possible radius for each angle of the sector.

At the beginning of the sector suction, the target radius R _s , which specifies the reference length for the suction arm and is incremented after each swiveling operation, is set to the inner radius Rj which the suction arm takes up in the retracted state.

Now the suction arm is on the left sector boundary W | rotated, but at most until it hits an obstacle; then the direction of rotation is reversed.

Then the suction cup is rotated in the current direction with a possible shortening of the arm length, see next section and Figure 12. Here, if the determined end angle cannot be turned on directly due to an obstacle, by gradually reducing the arm length while scanning the Edge contour of the obstacle tries to continue the rotation.

The rotation is stopped as soon as the suction arm reaches the end angle or can be freely rotated around the next step after a necessary shortening of the arm, since then the arm must first be extended again in order to follow the contour of the obstacle.

Then it is checked whether the corresponding sector boundary could be reached after completion of the turning process or whether all angles up to the sector boundary are marked with a radius smaller than the current target radius. The direction of rotation is reversed, R _s um, only if at least one of these conditions is met increases the diameter of the suction head and checks whether R _s exceeds the previously determined outer radius R _a . Since the outer edge of the sector was reached in this case, the naturally aspirated engine is stopped, the suction arm is retracted to R _j and the suction process continues as described in Fig. 10 and section "Description of the control procedure".

If this termination condition does not apply, an attempt is then made to extend the suction arm to R _s , see section "Arm extension with possible suction device rotation" and Fig. 13. In the event of an obstacle contact, the rotation is continued step by step in the current direction and then an attempt is made again, R _s to reach.

This macro ends when R _{s is reached} or when the evaluation of the angular field shows that all accessible areas have already been vacuumed in the direction of rotation.

Then you return to the macro "Suction cup rotation with possible arm shortening", see above.

Suction cup rotation with possible shortening of the arm

According to Fig. 12, the end angle of the rotation is calculated first, the i. A. not equal to the left or right wetting angle W | or W _r . For this purpose, it is checked whether an obstacle has already been detected during a previous swivel in this direction with a shorter arm length. In this case, a too large angle of rotation would cause the suction arm to hit the already known obstacle again, but not with the suction head and the touch sensor attached to it, but further back. The obstacle could then only be detected by means of the blocking sensor, which, however, only triggers when the contact pressure is significantly greater than that of the touch sensor and is also not intended for this application (see "Orientation of the suction device by means of sensors").

If the sector boundary W | or W _r reached, ie there was no obstacle, the immediate return takes place in Fig. 11, see previous section. The return also takes place if the rotation stop occurred due to a known obstacle that extends to the sector boundary, since then rotation cannot be continued with the current target radius behind the obstacle. If both conditions are not met, the suction head is turned back by 1 cm and the arm is then withdrawn, distinguishing two cases:

If there is a known but workable obstacle, i. H. the rotation can be continued behind with the target radius, the arm is drawn in far enough and rotated in front of the obstacle. Then you return to the previous flow chart.

If, on the other hand, the obstacle was detected for the first time with the current target radius, its contour must be scanned exactly in order to be able to optimally vacuum the edge. Therefore, in this case the arm length is only reduced by 1 cm, and then an attempt is made to turn the head by half a head width (the sector boundaries form an absolute limit, however).

The radii of the suction arm in the swept angular range are then saved in the angular field.

If the suction arm could be turned half the width of the head without contacting the obstacle again, or if the respective sector boundary was reached, Figure 11 jumps back. However, if the sensors report a new obstacle, it is checked again for continuation, as described above.

Arm extension with possible suction cup rotation

First, as shown in Fig. 13, an attempt is made to extend the suction arm to the current target angle R _s . After completing the arm extension, the arm is pivoted back by a maximum of half a head width up to the obstacle contact against the current direction of rotation. Since when an obstacle is bypassed, the forward rotation occurs in multiples of half the head diameter, the backward rotation is necessary to ensure that the contour of the obstacle to be avoided is exactly scanned. However, the reverse rotation must only be carried out if there was no change of direction beforehand and is only carried out if the suction arm could be extended by a certain minimum length. It is then checked whether the target radius has been reached or whether all subsequent angles in the direction of rotation with a radius smaller than R _{s are} already in the angular field. are marked and thus indicate a known obstacle up to the sector boundary. In both cases, the return takes place in Figure 11.

If there is a known obstacle in the direction of rotation, but that does not reach the sector boundary, the suction arm is then pulled in as far as necessary, rotated past the obstacle and then tried again to extend.

Otherwise, the suction arm is pulled back a little until the sensor no longer detects an obstacle and rotated half a head further. If rotation was not possible due to an obstacle, the jump back is made in Fig. 11.

If the arm could be rotated at least slightly, the swept area is marked in the angular field with the respective radii, and there is a return to the extension of the suction arm as described at the beginning.

Determination of the next suction cup position

The basic principle for determining the new vacuum position is to filter out the total of the tasks that are still open by evaluating various criteria to find the optimal task for the current location. If no new task is found from the current location, the previous suction cup positions are then examined in turn. If a new suction position can be determined from one of these old positions, the suction device is returned to this position and the new position is approached from here. At the beginning of the flow diagram in Fig. 14, the test position is set to the current suction cup position. Then all saved tasks are run through and checked to see whether they are possible continuations.

The following evaluations are carried out in the order listed:

First, the status in the suction field is used to check whether the saved position has already been vacuumed. In this case, the corresponding task is discarded and deleted.

If a possible candidate for the next position has already been determined, only those tasks that have at least the same priority are evaluated, cf. Section "Description of the Tax Procedure". If this condition is met, the distance of the task from the current test position is then calculated and the status in the suction field is used to check whether the suction head can be moved in a straight line to this position. For this purpose, the entire distance to be covered by the vacuum cleaner must be marked with status 1 and the task must at least be achieved by extending the vacuum arm.

From all positions that can be approached, the one is selected whose priority is either higher than the previously selected one or which has the larger x-coordinate value with the same priority. This criterion ensures that the surface to be vacuumed is always vacuumed from the back to the front.

If, after checking all the stored tasks, no position that can be approached was determined, the test position is set to the previous suction cup position and from there a loop is run through all tasks.

If it is no longer possible to continue from any of the previous suction positions, either because all tasks have already been processed or because the tasks that are still open cannot be reached by the suction device, the suction process stops.

Otherwise it is checked whether the test position from which a task was found is equal to the current suction cup position. While in this case the new position can be approached directly after rotating the suction cup in the corresponding direction, in all other cases the suction cup must first be reset to the test position.

In the case of several reset operations to be carried out, a path optimization is carried out by checking for each intermediate position whether it has been skipped and whether the suction device can possibly be moved back directly from its current position to the position from which the new suction position is subsequently assumed. A condition for a possible 'shortcut' is again that the vacuum cleaner may only drive over areas that are marked with status 1 in the suction field in order to avoid collisions with obstacles. Illustrations

Fig. 1: View of the suction cup

Fig. 2: Supervision of the vacuum cleaner

Fig. 3: Longitudinal section of the suction head

Fig. 4: Top view of the suction head

Fig. 5: Drive with blocking sensor

Fig. 6: Path control when vacuuming the sector

Fig. 7: Sector suction area with existing obstacles

Fig. 8: Line-up of sector suction areas

Fig. 9: Storage of the vacuumed areas

Fig. 10: Overall flow diagram of the suction control

Fig. 11: Flow chart 'Sucking the sector ahead'

Fig. 12: Flow chart 'Suction cup rotation with possible arm shortening'

Fig. 13: Flow chart 'arm extension with possible suction cup rotation'

Fig. 14: Flow chart 'Determination of a new suction cup position'

Claims

claims

1. A method for automatically controlling a self-propelled device, in particular a vacuum cleaner, with distance or contact sensors, characterized in that a close range around the device is determined and scanned, and possible new positions for the device are stored at the limits of this close range , then after selecting one of the positions stored in the current or previous step, depending on the degree of accessibility, an assigned priority and taking into account the presence of area that has not yet been scanned in the area of the possible new positions, the selected position is approached, and that then the described sequence of

Process steps are repeated until a predetermined total area has been completely covered or no position can be selected.

2. Method for the automatic control of a self-propelled device, in particular a vacuum cleaner, with distance or contact sensors, characterized in that the floor area scanned by the sensors is mapped into a two-dimensional data field in order to identify obstacles and free areas detected during the scanning as well as to mark possible new positions for the device by means of certain statuses, and that this field, in which an image of the accessible floor area with the contours of all obstacles and the bounding edges is gradually created, for determining control parameters for the device and for control purposes serves the area already covered.

3. The method according to claim 1, characterized in that the close range is determined by the range of the sensors.

4. The method according to claim 1, characterized in that after the detection of an obstacle by a sensor, the exact position of the

Obstacle is determined by taking into account the scanning direction.

5. The method according to claim 1, characterized in that after the scanning of the close range, new positions are only stored where no obstacles have been detected and also do not adjoin any surface areas which have already been scanned from an earlier position of the device.

6. The method according to claim 2, characterized in that when mapping a point (x, y) in the data field with the dimensions x_max and yjnax for negative coordinates a transformation into a positive coordinate range, e.g. B. by forming x_max - | x | or y_max - | y |.

7. The method according to claim 2, characterized in that upon renewed scanning of an area already marked in the data field, all statuses of this area are updated in accordance with the new sensor data.

8. The method according to claim 1 and 2, characterized in that only those positions are considered when selecting a new position for the device that are not marked in the data field as already scanned.

9. The method according to claim 1, characterized in that when storing new positions different priorities for these positions are assigned, and that when selecting a new position for the device only those positions are taken into account, the priority of which one already provisionally in the current Process step does not fall below the selected position.

10. The method according to claim 1, characterized in that only those positions are taken into account when selecting a new position, which lie in a certain partial area, and that this partial area is modified during the course of the method, if no new position within the current partial area can be selected.

11. The method according to claim 1, characterized in that the distance between a possible new position and the current position of the device is taken into account when selecting a new position.

12. The method according to claim 1, characterized in that when selecting a new position, the direction in which a possible new position from the current position of the device is taken into account.

13. The method according to claim 1, characterized in that the distance covered since the storage of a position is taken into account when selecting a new position.

14. The method according to claim 1 and 2, characterized in that when selecting a new position for the device by evaluating the data field it is ensured that the new position can be reached by the device directly, only areas being allowed to be passed over that have already been scanned and are not marked as an obstacle.

15. The method according to claim 1 and 2, characterized in that after the selection of a new position by evaluating the data field, the shortest route there within the already scanned area is determined by avoiding obstacles and the device is moved along this route.

16. The method according to claim 1 and 2, characterized in that the device can be reset to any previous positions and certain intermediate positions can be skipped when resetting the device over several previous positions, if a check in the data field shows that the device during its movement no areas marked as obstacles have to be crossed.

17. The method according to claim 1 or 2, characterized in that, if an unexpected obstacle blocks the movement of the device, this determines the contours of the obstacle by scanning with the sensors.

18. The method according to claim 1 and 2, characterized in that after approaching a new position, the new close range is determined by evaluating the data field so that only a slight overlap with neighboring areas already scanned occurs.

19. The method according to claim 1, characterized in that the scanning of the close range is carried out by moving the entire device or a part thereof.

20. The method according to claim 1 or 2, characterized in that the bottom surface is simultaneously cleaned during the scanning.

21. The method according to claim 1 or 2, characterized in that the scanning is carried out by a movable arm so that areas not yet scanned are first swept by the front end of the arm.

22. The method according to claim 1 or 2, characterized in that the scanning is carried out by a movable arm, the front end of which is guided along at the smallest possible distance along detected obstacles.

23. The method according to claim 1, characterized in that the scanning is carried out by a movable arm and the close range around the device is selected in the form of a circular sector.

24. The method according to claim 1 or 2, characterized in that the scanning is carried out by repeated left and right rotation of the device, each with an increased length of a movable arm.

25. The method according to claim 1 or 2, characterized in that the scanning is carried out by repeated left and right rotation of the device, each with an increased length of a movable arm, and thereby a multiple scanning of the same is avoided by shortening the arm in the angular range of obstacles already detected.

26. The method according to claim 2, characterized in that by evaluating the information in the data field, the cleaning of the floor surface takes place only in those areas which are marked as not yet cleaned in the data field.

27. The device, in particular a vacuum cleaner for carrying out the method according to one of claims 1 to 26 with driven wheels and steering wheels or controllable drive wheels and sensors and an extendable arm with a head arranged at its front end, characterized in that in addition to two driven wheels as the third Point of contact serves the head, which z. B. on rollers, balls, wheels or bristles.

28. The device, in particular a vacuum cleaner for carrying out the method according to one of claims 1 to 26 with driven wheels and steering wheels or controllable drive wheels and sensors and an extendable arm with a head arranged at the front end thereof, characterized in that at least one driven plate brush on the head is arranged.

29. The device, in particular a vacuum cleaner for carrying out the method according to one of claims 1 to 26 with driven wheels and steering wheels or controllable drive wheels and sensors and an extendable arm with a head arranged at its front end, characterized in that in the region of the head contact and distance sensors are arranged with which both obstacles to the movement of the arm can be detected, as well as those obstacles which do not block the arm but block the movement of the device.

30. Device, in particular vacuum cleaner for carrying out the method according to one of claims 1 to 26 with driven wheels and steering wheels or controllable drive wheels and sensors, characterized in that that the drives, e.g. B. via worm gears, are connected elastically to the respective wheel, the displacement of the drives which occurs when the device is blocked by an obstacle, closes an electrical circuit.

31.Device according to one of claims 27, 28, or 29, characterized in that the arm is designed as a telescopic arm.

32. Device according to one of claims 27, 28 or 29, characterized in that the arm has a rectangular cross section.

33. Apparatus according to claim 27, characterized in that the contact pressure of the head can be varied by shifting the weight.

34. Apparatus according to claim 28 or 29, characterized in that the arm is designed as a telescopic arm which is rotatably mounted at its rear end about a horizontal axis or vertically movable.

35. Apparatus according to claim 28, characterized in that the drive of the brush (s), for. B. via a slidable shaft, by a motor which is attached to the base of the device.

36. Apparatus according to claim 28, characterized in that at least one brush has bristles directed obliquely inwards and is surrounded by a dense ring of soft bristles inclined obliquely outwards.

37. Apparatus according to claim 29, characterized in that a contact sensor is designed so that around the head of the arm around a small mutual distance two electrical conductors are attached, of which the outer one is elastically pressed against the inner one in contact with an obstacle and this closes an electrical circuit.

38. Apparatus according to claim 29, characterized in that a distance sensor, for. B. by ultrasound or by means of electromagnetic waves measures the clear height above the head.

39. Apparatus according to claim 29, characterized in that a sensor, for. B. in the form of a mechanical button or contactless, steps in the flooring detected.

40. The method according to claim 30, characterized in that after the blocking sensor has been triggered, the device is reset to the extent that no more blocking is displayed, and then a further advance is carried out at a reduced speed.