JP4178185B2 - Wearable motion assist device, drive source control method and program in wearable motion assist device - Google Patents

Description

  The present invention relates to a wearable movement assist device, and more particularly to an improvement in a wearable motion assist device, a control method, and a program for assisting or acting on a wearer's movement.

  For the physically handicapped and the elderly, even if it is a healthy person, even a simple operation can be very difficult. For this reason, various power assist devices have been developed today in order to assist or substitute for the operations of these people.

  As these power assist devices, for example, there are wearable motion assist devices (hereinafter simply referred to as “motion assist devices”) worn by users (hereinafter referred to as “wearers”). This type of motion assisting device corresponds to an angle sensor (detecting means) that detects the angle of the wearer's joint according to the wearer's movement and a series of phases that constitute the wearer's movement pattern. What is provided with the memory (storage means) which each stored the joint angle as a reference parameter is being developed (for example, nonpatent literature 1).

  Here, the phase is a minimum unit for dividing a series of motion patterns, and the power required for assisting the wearer's motion is determined for each phase.

  This motion assisting device includes autonomous control means for identifying each phase of the wearer's motion pattern and generating a command signal (control signal) for causing the drive source to generate power corresponding to this phase. .

The autonomous control means comprises program Ru to execute the autonomous control to the computer, and joint angle detected by the angle sensor, by comparing the joint angle of the reference parameters stored in the memory, the wearer of The operation pattern phase can be specified.

  Further, in the motion assist device, for example, if the joint angles corresponding to each phase of a series of motion patterns from standing to standing are stored in the memory as reference parameters in advance, control of the drive source by the autonomous control means Therefore, the wearer can stand up easily by the power source assisting the muscle force that rotates the waist and knees of the seated wearer.

Therefore, in this motion assist device, if the gain of the command signal by the autonomous control means is appropriately set, the power (muscle strength) that the wearer should generate can be suppressed as much as possible. This is preferable in order to reduce the burden.
Takao Nakai, Suwoong Lee, Hiroaki Kawamoto and Yoshiyuki Sankai, “Development of Power Assistive Leg for Walking Aid using EMG and Linux,” Second Asian Symposium on Industrial Automation and Robotics, BITECH, Bangkok, Thailand, May 17-18, 2001

  However, the above-described power assist device controls the drive source by the autonomous control means so as to have a preset operation pattern, and the gain of the command signal by the autonomous control means becomes a predetermined one. It is set to.

  For this reason, in this power assist device, for example, once the operation of raising the wearer is started, even if the wearer wants to sit down on the way, the intention of the wearer cannot be reflected, and the wearer Will be forced to have uniform action.

  In other words, this power assist device has the advantage that the wearer can suppress the power (muscle strength) that the wearer should generate as much as possible, but on the other hand, the wearer is forced to perform a uniform operation, so it is extremely convenient. There is a risk of damaging the sex.

  Therefore, in view of the above circumstances, the present invention is capable of suppressing the power (muscle strength) that the wearer should generate as much as possible and suppressing the situation that impairs the wearer's convenience. It is an object of the present invention to provide a device, a method for controlling a drive source in an operation auxiliary device, and a program.

The invention according to claim 1 is a wearable movement assist device that assists or substitutes for the movement of the wearer,
A motion assisting wearing device having a drive source for applying power to the wearer;
First detection means for detecting an angle of a joint of the wearer according to the operation of the wearer;
Second detection means for detecting a biological signal associated with the muscle activity of the wearer;
Storage means for storing a reference parameter consisting of a data group in which the joint angle and biological signal of the wearer are set so as to correspond to each of a series of phases constituting the wearer's operation pattern;
Phase identification means for identifying the phase of the wearer's movement pattern by comparing the joint angle detected by the first detection means with the joint angle of the reference parameter ;
A command signal is generated for causing the drive source to generate power according to the phase specified by the phase specifying means, and the drive source is controlled to assist an operation pattern according to the wearer's intention. Autonomous control means,
Whether or not the difference between the biological signal of the reference parameter corresponding to the joint angle detected by the first detecting means and the biological signal detected by the second detecting means exceeds a preset allowable value. A judging means for judging;
Changing means for changing a command signal to be generated by the autonomous control means according to the difference when the determination means determines that the difference exceeds the allowable value;
It is characterized by comprising.

  According to a second aspect of the present invention, when the changing means has a biological signal of a reference parameter corresponding to the joint angle detected by the first detecting means larger than the biological signal detected by the second detecting means. Further, the command signal generated by the autonomous control means is reduced.

According to a third aspect of the present invention, the motion assisting wearing device comprises:
Waist belt,
A right leg auxiliary part provided below from the right side of the waist belt;
A left leg auxiliary part provided below from the left side of the waist belt;
Have
The right leg auxiliary part and the left leg auxiliary part are
A first frame extending downward to support the waist belt;
A second frame extending below the first frame;
A third frame extending below the second frame;
A fourth frame provided at the lower end of the third frame, on which the back of the leg of the wearer is placed;
A first joint interposed between a lower end of the first frame and an upper end of the second frame;
A second joint interposed between a lower end of the second frame and an upper end of the third frame;
It is characterized by having.

In the invention according to claim 4, the first joint is provided at a height position that coincides with the hip joint of the wearer,
The second joint is provided at a height position coinciding with the knee joint of the wearer.

The invention according to claim 5 is provided with a first drive source for transmitting a driving force to the second joint so as to rotate the second frame,
The second joint is provided with a second driving source for transmitting a driving force so as to rotate the third frame.

  The invention described in claim 6 is characterized in that the first and second drive sources have an angle sensor for detecting a joint angle.

According to a seventh aspect of the present invention, there is provided a drive source for generating power for assisting or acting on the wearer's movement, and first detection means for detecting an angle of the wearer's joint according to the wearer's movement. And a second detection means for detecting a biological signal associated with the muscle activity of the wearer and an autonomous control means for generating a command signal for generating power in the drive source. A method of controlling the drive source,
A first step of previously storing in the storage means a reference parameter consisting of a data group in which the wearer's joint angle and biological signal are set so as to correspond to each of a series of phases constituting the wearer's motion pattern;
A second step of identifying the phase of the wearer's movement pattern by comparing the joint angle detected by the first detection means with the joint angle of the reference parameter ;
The autonomous control means generates a command signal for causing the drive source to generate power according to the identified phase, and the drive source is controlled to assist the operation pattern according to the wearer's intention and a third step you,
Whether or not the difference between the biological signal of the reference parameter corresponding to the joint angle detected by the first detecting means and the biological signal detected by the second detecting means exceeds a preset allowable value. A fourth step of determining;
And a fifth step of changing a command signal to be generated by the autonomous control means according to the difference when the difference exceeds the allowable value.

  The invention according to claim 8 is a program for causing a computer to execute the control method according to claim 7.

  According to the present invention, the difference between the biological signal of the reference parameter corresponding to the joint angle detected by the first detecting means and the biological signal detected by the second detecting means exceeds a preset allowable value. If it is determined whether or not the difference exceeds the allowable value, the command signal to be generated by the autonomous control means is changed according to the difference, for example, the wearer himself tries to operate and It is possible to increase or decrease the assist force in response to a change in muscle strength when an operation different from the phase of the series of operation patterns is performed. As a result, the power (muscle strength) that the wearer should generate can be suppressed as much as possible, and the wearer's convenience is impaired because the wearer is not forced to perform uniform operations. Can be suppressed, and convenience can be further improved in response to changes in the intention of the wearer.

  Further, according to the present invention, the assist force can be transmitted to the leg in accordance with the leg movement of the wearer. The operation can be efficiently assisted, and the assist force can be controlled to reflect the intention of the wearer even when the wearer stops the movement during the leg movement process. Furthermore, for example, even when the wearer changes the muscular strength during the operation before ending the series of phases, it becomes possible to control the wearer's operation so as not to be hindered by reducing the assist force. It is possible to prevent an assist force that is contrary to the intention of the wearer.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing a control system applied to an embodiment of a wearable movement assist device according to the present invention.
As shown in FIG. 1, the control system of the movement assist device 10 detects a driving source 140 that applies assist force to the wearer 12 and a joint angle (physical phenomenon) corresponding to the movement of the wearer 12. A physical phenomenon detection means 142 that detects the muscle potential (biological signal) corresponding to the muscle force generated by the wearer 12.

  The data storage unit 146 stores a reference parameter database 148 and a command signal database 150.

  The joint angles (θknee, θhip) detected by the physical phenomenon detection unit 142 and the myoelectric potential signals (EMGknee, EMGhip) detected by the biological signal detection unit 144 are input to the reference parameter database 148. The phase specifying unit 152 specifies the phase of the movement pattern of the wearer 12 by comparing the joint angle detected by the physical phenomenon detecting unit 142 with the joint angle of the reference parameter stored in the reference parameter database 148.

  The difference deriving unit 154 derives a difference between the biological signal of the reference parameter corresponding to the joint angle detected by the physical phenomenon detecting unit 142 and the biological signal detected by the biological signal detecting unit 144, and the difference is set in advance. It is determined whether or not the allowable value is exceeded.

  In the gain changing unit 156, when the difference deriving unit 154 determines that the difference exceeds the preset allowable value, the gain change unit 156 sets the gain P according to the command signal (control signal) to be generated by the autonomous control unit 160. The correction signal is output to the autonomous control means 160 so as to change.

  When the autonomous control means 160 obtains the control data of the phase specified by the phase specifying means 152, it generates a command signal according to the control data of this phase and causes the drive source 140 to generate this power. The command signal is supplied to the power amplifier 158. Further, the autonomous control means 160 corrects the gain P with the correction signal obtained from the gain changing means 156 for the control data of the phase specified by the phase specifying means 152, and provides a command signal corresponding to the corrected gain P. This is supplied to the power amplification means 158.

In the autonomous control means 160 , when the difference derivation means 154 determines that the difference does not exceed the preset allowable value, the correction signal is not supplied from the gain change means 156, so that it is obtained from the command signal database 150. The corrected control data is supplied to the power amplification means 158 without correction.

  As described above, the autonomous control unit 160 amplifies the power according to the difference value between the biological signal corresponding to the joint angle detected by the physical phenomenon detection unit 142 and the biological signal detected by the biological signal detection unit 144. Since the command signal supplied to the means 158 is arbitrarily corrected, it is possible to perform control combining autonomous control and optional control. Accordingly, even when the wearer 12 stops the operation during the operation and performs another operation, the drive source 140 can be controlled so that the intention of the wearer 12 is reflected.

Here, a specific configuration example of the wearable motion assist device 10 according to the present invention will be described in detail.
FIG. 2 is a perspective view of a state in which an embodiment of the wearing type movement assisting device according to the present invention is mounted as seen from the front side. FIG. 3 is a perspective view of the wearing type movement assisting device according to the present invention, as viewed from the rear side.

  As shown in FIGS. 2 and 3, the motion assisting device 10 is self-supporting, for example, a person with lower limb movement dysfunction who cannot walk due to a decrease in skeletal muscle strength, or a patient who performs rehabilitation of walking movement. It is a device that assists the walking movement of people who have difficulty walking, and it detects the biological signal (surface myoelectric potential) that is generated when the muscle force is generated by the signal from the brain, and from the actuator based on this detection signal Operates to apply driving force.

  Accordingly, the motion assisting device 10 is completely different from a so-called playback robot configured to control the robot hand based on data input in advance, and is also called a robot suit or a powered suit.

  When the wearer 12 wearing the motion assisting device 10 performs a walking motion with his / her own intention, a driving torque corresponding to the biological signal generated at that time is applied from the motion assisting device 10 as an assisting force. It is possible to walk with half the strength of the muscle strength required. Therefore, the wearer 12 can walk while supporting the overall weight by the resultant force of his / her muscle strength and the driving torque from the actuator (in this embodiment, an electric driving motor is used).

  At that time, the motion assisting device 10 controls the assisting force (motor torque) applied according to the movement of the center of gravity accompanying the walking motion to reflect the intention of the wearer 12 as described later. Therefore, the actuator of the motion assisting device 10 is controlled so as not to apply a load that is against the intention of the wearer 12 and is controlled so as not to hinder the operation of the wearer 12.

  In addition to the walking motion, the motion assisting device 10 can assist, for example, an operation when the wearer 12 stands up from a state of sitting on a chair, or an operation when sitting on the chair from a standing state. Furthermore, the power assist can be performed when the wearer 12 goes up or down the stairs. In particular, when the muscular strength is weak, it is difficult to move up the stairs or move up from the chair, but the wearer 12 wearing the movement assisting device 10 is given drive torque according to his / her intention. This makes it possible to operate without worrying about muscular weakness.

Here, an example of the configuration of the motion assisting device 10 will be described.
As shown in FIGS. 2 and 3, the motion assisting device 10 is provided with an actuator (corresponding to the drive source 140) in the motion assisting wearing tool 18 worn by the wearer 12. Actuators include a right thigh drive motor 20 located at the right hip joint of the wearer 12, a left thigh drive motor 22 located at the left hip joint of the wearer 12, and a right knee drive motor located at the right knee joint of the wearer 12. 24 and a left knee drive motor 26 located at the left knee joint of the wearer 12. These drive motors 20, 22, 24, and 26 are servo motors whose drive torque is controlled by a control signal from a control device, and have a reduction mechanism (not shown) that reduces the motor rotation at a predetermined reduction ratio. Thus, a small but sufficient driving force can be applied.

  In addition, batteries 32 and 34 that function as a power source for driving the drive motors 20, 22, 24, and 26 are attached to the waist belt 30 attached to the waist of the wearer 12. The batteries 32 and 34 are rechargeable batteries, and are distributed on the left and right so as not to hinder the walking motion of the wearer 12.

  In addition, the control bag 36 to be worn on the back of the wearer 12 houses devices such as a control device, a motor driver, a measuring device, and a power circuit, which will be described later. The lower portion of the control back 36 is supported by the waist belt 30 and attached so that the weight of the control back 36 does not become a burden on the wearer 12.

  The motion assisting device 10 includes surface myoelectric potential sensors 38a and 38b that detect surface myoelectric potential (EMGhip) accompanying the movement of the right thigh of the wearer 12, and surface myoelectric potential ( EMGhip), myoelectric sensors 42a and 42b for detecting the surface myoelectric potential (EMGknee) associated with the movement of the right knee, and the surface myoelectric potential (EMGknee) associated with the movement of the left knee EMG sensors 44a and 44b are provided.

  These myoelectric potential sensors 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b are detection means for measuring the surface myoelectric potential when the skeletal muscles generate muscle force, and are weak potentials generated in the skeletal muscles. Has an electrode (not shown). In the present embodiment, each myoelectric potential sensor 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b is attached so as to be attached to the skin surface of the wearer 12 with an adhesive seal covering the periphery of the electrode. .

  In the human body, acetylcholine, a synaptic transmitter, is released on the surface of the muscle that forms skeletal muscle by the command from the brain. As a result, the ionic permeability of the muscle fiber membrane changes and action potential (EMG) appear. Then, the contraction of the muscle fiber is generated by the action potential, and the muscle force is generated. Therefore, by detecting the myoelectric potential of the skeletal muscle, it becomes possible to estimate the muscle force generated during the walking motion, and the assist force necessary for the walking motion can be obtained from the virtual torque based on the estimated muscle strength. It becomes possible.

  Muscles expand and contract when proteins called actin and myosin are supplied by blood, but muscles are generated when they contract. For this reason, in a joint in which two bones are connected so as to be rotatable, a flexor that generates a force in the direction of bending the joint and an extensor that generates a force in the direction of extending the joint are mounted between the two bones. It is built.

  The human body has several muscles to move the legs from the waist down, the iliopsoas muscle that raises the thigh forward, the gluteal muscle that lowers the thigh, the quadriceps muscle to extend the knee, and the knee. There are biceps femoris.

  The myoelectric potential sensors 38a and 40a are affixed to the front side of the base of the thigh of the wearer 12, and measure the myoelectric potential corresponding to the muscle strength when the leg is pushed forward by detecting the surface myoelectric potential of the iliopsoas muscle. .

  The myoelectric potential sensors 38b and 40b are affixed to the buttocks of the wearer 12, and measure the myoelectric potential according to the muscle force when, for example, the kicking force or the stairs rises by detecting the surface myoelectric potential of the gluteus To do.

  The myoelectric potential sensors 42a and 44a are attached to the front side of the wearer 12 above the knee, detect the surface myoelectric potential of the quadriceps femoris muscle, and measure the myoelectric potential according to the muscle force that moves downward from the knee.

  The myoelectric potential sensors 42b and 44b are attached to the rear side of the wearer 12 above the knee, detect the surface myoelectric potential of the biceps femoris muscle, and measure the myoelectric potential according to the muscle force to return the knee back.

  Therefore, in the motion assisting device 10, the four drive motors 20, 22, 24, 26 are based on the surface myoelectric potentials detected by these myoelectric potential sensors 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b. The driving current to be supplied to the vehicle is obtained, and the driving motors 20, 22, 24, and 26 are driven by this driving current, so that an assist force is applied to assist the walking motion of the wearer 12.

  In addition, in order to smoothly move the center of gravity by walking, it is necessary to detect the load applied to the back of the leg. Therefore, reaction force sensors 50a, 50b, 52a, 52b (shown by broken lines in FIGS. 2 and 3) are provided on the backs of the left and right legs of the wearer 12.

  The reaction force sensor 50a detects a reaction force against the load on the front side of the right leg, and the reaction force sensor 50b detects a reaction force on the load on the rear side of the right leg. The reaction force sensor 52a detects a reaction force against the load on the left leg front side, and the reaction force sensor 52b detects a reaction force against the load on the left leg rear side. Each of the reaction force sensors 50a, 50b, 52a, and 52b includes, for example, a piezoelectric element that outputs a voltage corresponding to an applied load, and changes in load accompanying weight shift and grounding of the wearer's 12 leg and the ground. The presence or absence of each can be detected.

Here, the configuration of the motion assisting wearing device 18 will be described with reference to FIGS. 4 and 5 together.
FIG. 4 is a left side view of the motion assisting wearing tool 18. FIG. 5 is a rear view of the motion assisting wearing tool 18.

  As shown in FIGS. 4 and 5, the movement assisting wearing device 18 includes a waist belt 30 that is worn on the waist of the wearer 12, and a right leg auxiliary portion 54 that is provided below the right side of the waist belt 30. And a left leg auxiliary portion 55 provided below the left side portion of the waist belt 30.

  The right leg auxiliary part 54 and the left leg auxiliary part 55 are arranged symmetrically, and extend downward from the first frame 56 so as to support the waist belt 30 and the first frame 56. A second frame 58 formed along the outer thigh of the wearer 12, a third frame 60 extending downward from the second frame 58 and formed along the outer shin of the wearer 12, and the wearer And a fourth frame 62 on which the soles of the twelve legs (shoe soles when wearing shoes) are placed.

  A first joint 64 having a bearing structure is interposed between the lower end of the first frame 56 and the upper end of the second frame 58, and the first frame 56 and the second frame 58 are rotatably connected. is doing. The first joint 64 is provided at a height position coinciding with the hip joint, the first frame 56 is coupled to the support side of the first joint 64, and the second frame 58 is disposed on the rotation side of the first joint 64. Are combined.

  Further, a second joint 66 having a bearing structure is interposed between the lower end of the second frame 58 and the upper end of the third frame 60, and the second frame 58 and the third frame 60 can be rotated. It is linked to. The second joint 66 is provided at a height position that coincides with the knee joint, the second frame 58 is coupled to the support side of the second joint 66, and the third frame 60 is the rotation side of the second joint 66. Is bound to.

  Therefore, the second frame 58 and the third frame 60 are attached so that a pendulum motion can be performed with respect to the first frame 56 fixed to the waist belt 30 with the first joint 64 and the second joint 66 as pivot points. ing. That is, the second frame 58 and the third frame 60 are configured to perform the same operation as the leg of the wearer 12.

  A motor bracket 68 is provided on the support side of the first joint 64 and the second joint 66. The motor bracket 68 has a motor support portion 68a protruding in the outer horizontal direction, and the drive motors 20, 22, 24, and 26 are attached to the motor support portion 68a in a vertical state. Therefore, the drive motors 20, 22, 24, and 26 are provided so as not to protrude greatly to the side and to make it difficult to contact surrounding obstacles or the like during a walking motion.

  In addition, the first joint 64 and the second joint 66 transmit the drive torque to the second frame 58 and the third frame 60 on which the rotation shafts of the drive motors 20, 22, 24, and 26 are driven via gears. Is configured to do.

  Furthermore, the drive motors 20, 22, 24, and 26 have angle sensors (corresponding to the physical phenomenon detection means 142) 70, 72, 74, and 76 that detect joint angles. The angle sensors 70, 72, 74, and 76 include, for example, a rotary encoder that counts the number of pulses proportional to the joint angles of the first joint 64 and the second joint 66, and corresponds to the number of pulses corresponding to the joint angle. An electric signal is output as a sensor output.

  The angle sensors 70 and 72 detect a rotation angle between the first frame 56 and the second frame 58 corresponding to the joint angle (θhip) of the hip joint of the wearer 12. Further, the angle sensors 74 and 76 detect a rotation angle between the lower end of the second frame 58 and the third frame 60 corresponding to the joint angle (θknee) of the knee joint of the wearer 12.

  It should be noted that the first joint 64 and the second joint 66 are configured to be rotated only within an angular range in which the wearer's 12 hip joint and knee joint can be rotated, so that the wearer's 12 hip joint and knee joint can move unreasonably. A stopper mechanism (not shown) is built in so as not to give the noise.

  A first fastening belt 78 that is fastened to the thigh of the wearer 12 is attached to the second frame 58. A second fastening belt 80 that is fastened under the knee of the wearer 12 is attached to the third frame 60. Accordingly, the drive torque generated by the drive motors 20, 22, 24, 26 is transmitted to the second frame 58 and the third frame 60 via gears, and further via the first fastening belt 78 and the second fastening belt 80. Then, it is transmitted as an assist force to the leg of the wearer 12.

  The fourth frame 62 is rotatably connected to the lower end of the third frame 60 via a shaft 82. Furthermore, the lower end of the fourth frame 62 is provided with a heel receiving portion 84 on which the heel portion of the shoe sole of the wearer 12 is placed. The second frame 58 and the third frame 60 can be adjusted in length in the axial direction by a screw mechanism, and can be adjusted to any length according to the length of the leg of the wearer 12. ing.

  Each of the frames 56, 58, 60, 64 is made of metal, and can support the weights of the batteries 32, 34, the control back 36, and the motion assisting attachment 18 provided on the waist belt 30. That is, the motion assisting device 10 is configured such that the weight of the motion assisting wearing tool 18 or the like does not act on the wearer 12, and is attached so as not to apply an extra load to the wearer 12 whose muscle strength has decreased.

FIG. 6 is a block diagram of each device constituting the motion assisting device 10.
As shown in FIG. 6, the batteries 32 and 34 supply power to the power supply circuit 86. The power supply circuit 86 converts the power into a predetermined voltage and supplies a constant voltage to the input / output interface 88. Further, the charging capacity of the batteries 32 and 34 is monitored by the battery charging warning unit 90. When the battery charging warning unit 90 decreases to a preset remaining amount, a warning is issued to the wearer 12 for battery replacement or Notify charging.

  The first to fourth motor drivers 92 to 95 that drive the drive motors 20, 22, 24, and 26 amplify the drive voltage corresponding to the control signal from the control device 100 via the input / output interface 88 and drive each drive. Output to motors 20, 22, 24, and 26.

The surface myoelectric potential detection signals output from the myoelectric potential sensors 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b are first to eighth differential amplifiers (corresponding to the power amplification means 158) 101- The signal is amplified by 108, converted into a digital signal by an A / D converter (not shown), and input to the control device 100 via the input / output interface 88. Note that the myoelectric potential generated in the muscle is weak. Therefore, for example, a first to eighth differential amplifiers 101 to 108, to amplify the myoelectric potential of 30μV about computer can determine 3V, it is necessary to 10 ⁵ times become 100dB amplification factor of.

  Further, the angle detection signals output from the angle sensors 70, 72, 74, and 76 are input to the first to fourth angle detection units 111 to 114, respectively. The first to fourth angle detectors 111 to 114 convert the number of pulses detected by the rotary encoder into an angle data value corresponding to the angle, and the detected angle data is transmitted via the input / output interface 88 to the control device. 100 is input.

  The reaction force detection signals output from the reaction force sensors 50a, 50b, 52a, and 52b are input to the first to fourth reaction force detection units 121 to 124, respectively. The first to fourth reaction force detectors 121 to 124 convert the voltage detected by the piezoelectric element into a digital value corresponding to the force, and the detected reaction force data is transmitted to the control device via the input / output interface 88. 100 is input.

  A memory (corresponding to the data storage means 146) 130 is a storage means for storing each data, and control data for each phase set for each operation pattern (task) such as a standing motion, a walking motion, and a seating motion is stored in advance. A stored database storage area 130A, a control program storage area 130B in which a control program for controlling each motor is stored, and the like are provided. In this embodiment, a reference parameter database 148 and a command signal database 150 shown in FIGS. 8 and 9 described later are stored in the database storage area 130A.

  The control data output from the control device 100 is output to the data output unit 132 or the communication unit 134 via the input / output interface 88, and displayed on a monitor (not shown) or a data monitoring computer, for example. It can also be transferred to data communication (not shown).

  Further, the control device 100 compares the joint angles detected by the angle sensors (first detection means) 70, 72, 74, and 76 with the joint angle of the reference parameter, thereby changing the phase of the movement pattern of the wearer 12. An autonomous control means (corresponding to the autonomous control means 160) 100A for generating a command signal for identifying and generating power corresponding to this phase in the drive motors (drive sources) 20, 22, 24, 26; The difference between the biological signal of the reference parameter corresponding to the joint angle and the myoelectric potential (biological signal) detected by the myoelectric potential sensors (second detection means) 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b. Determining means (equivalent to the difference deriving means 154) 100B for determining whether or not the difference exceeds a preset allowable value, and determining that the difference exceeds the allowable value Case, and a (corresponding to the gain change unit 156) 100C changing means for changing a command signal to be generated by the autonomous control unit 100A in accordance with the difference.

FIG. 7 is a diagram showing an example of each task and phase stored in the reference parameter database 148.
As shown in FIG. 7, the tasks for classifying the movement of the wearer 12 include, for example, a task A having rising movement data for shifting from the seated state to the away state, and a walking operation in which the worn wearer 12 walks. Task C having data, task C having seating motion data for transitioning from a standing state to a seating state, and task D having stairs climbing motion data for climbing stairs from the standing state are stored in the reference parameter database 148. Yes.

  Each task is set with a plurality of phase data that further define the minimum unit motion. For example, the task B for walking motion has a phase B1 having motion data in a state where both left and right legs are aligned, Phase B2 having motion data when the right leg is put forward, Phase B3 having motion data in a state where the left leg is put forward and aligned with the right leg, and the left leg is put in front of the right leg The phase B4 having the operation data is stored.

FIG. 8 is a diagram schematically showing the reference parameter database 148. As shown in FIG. 8, in the reference parameter database 148, the joint angle reference parameter θ _A1 (t)..., The myoelectric potential reference for each phase obtained by dividing each of the tasks A, B. Parameters E _A1 (t) are stored.

FIG. 9 is a diagram schematically showing the command signal database 150. As shown in FIG. 9, in the command signal database 150, a data area of each phase obtained by dividing each task into areas of tasks A, B... Set for each operation is set. The command function f _A1 (t)..., Gain P _A1 , command signal P _A1 xf _A1 (t).

Here, the procedure of the control process executed by the control device 100 will be described with reference to the flowchart of FIG.
As shown in FIG. 10, the control device 100 detects the joint angle (θknee, detected by the physical phenomenon detection means 142 (angle sensors 70, 72, 74, 76) in step S11 (hereinafter, “step” is omitted). θhip). Next, in S12, the myoelectric potential signals (EMGknee, EMGhip) detected by the biological signal detection means (myoelectric potential sensors 38a, 38b, 40a, 40b, 42a, 42b, 44a, 44b) 144 are acquired.

Subsequently, the process proceeds to S13, in which the joint angles (θknee, θhip) and myoelectric potential signals (EMGknee, EMGhip) acquired in S11 and S12 are checked against the reference parameter database 148 and the task corresponding to the operation of the wearer 12 is performed. Identify phases (phase identification means) . In the next S14, the command function f (t) and gain P corresponding to the phase specified in S13 are selected (autonomous control means).

  In S15, the difference between the biological signal (EMGop) of the reference parameter corresponding to the joint angle detected by the physical phenomenon detection means 142 and the myoelectric potential signal (EMGex) is calculated by the biological signal detection means 144, and ΔEMG (= EMGop−EMGex) is derived (determination means).

  In the next S16, the difference ΔEMG calculated in S15 is compared with a preset allowable value (threshold) to check whether the difference ΔEMG is less than the allowable value. In S16, when the difference ΔEMG is less than the allowable value, the myoelectric potential with respect to the joint motion of the wearer 12 corresponds to the motion of the wearer 12, and therefore the drive source 140 (drive motors 20, 22, 24, 26). ) Is determined to be able to be applied to the leg of the wearer 12 as an assist force.

  Therefore, when the difference ΔEMG is less than the allowable value in S16, the process proceeds to S17, and a command signal is sent to the power amplifying means 158 (motor drivers 92 to 95). Thereby, the drive source 140 (drive motors 20, 22, 24, 26) generates a drive torque based on the joint angles (θknee, θhip) and myoelectric potential signals (EMGknee, EMGhip) obtained from the wearer 12, This driving torque is transmitted as an assist force to the legs of the wearer 12 via the second frame 58, the third frame 60, the first fastening belt 78, and the second fastening belt 80.

  In S16, when the difference ΔEMG exceeds the allowable value, the myoelectric potential for the joint motion of the wearer 12 does not correspond to the motion of the wearer 12, and thus the drive source 140 (drive motors 20, 22, 24). , 26) is determined not to correspond to the movement of the wearer 12 about to operate. Accordingly, when the difference ΔEMG is equal to or larger than the allowable value in S16, the process proceeds to S19, and the gain P changing process is performed (changing means). That is, in S19, the gain P ′ = P × {1− (ΔEMG / EMGop)} is calculated and changed to the correction gain P ′ (<P).

  In S17, the command signal (control signal) generated by the correction gain P ′ has a smaller value than that of the gain P, and the power amplifying means 158 (motor drivers 92 to 95) has a value smaller than that of the gain P. A small control amount is supplied. As a result, the drive source 140 (drive motors 20, 22, 24, 26) generates a drive torque smaller than that in the case of the gain P.

  As a result, the drive source 140 (drive motors 20, 22, 24, and 26) can drive torque based on measured values of myoelectric signals (EMGknee, EMGhip) corresponding to the intention of the wearer 12 regardless of the phase of each operation. This driving torque is transmitted as an assisting force to the leg of the wearer 12 via the second frame 58, the third frame 60, the first fastening belt 78, and the second fastening belt 80.

  As described above, since the gain P is changed in S19, for example, even when the wearer 12 stops the operation (phase) during the operation and moves to another operation (phase), the wearer 12 When the myoelectric potential signal of 12 decreases, the assist force also decreases, and control can be performed so that the initial operation is not forced against the intention of the wearer 12. Therefore, the wearer 12 can obtain an assist force according to the intention of the wearer 12 by a control method in which the autonomous control method as described above and the voluntary control similar to the voluntary control are mixed.

  In S18, it is confirmed whether the control process for the final phase of the task has been performed. If the control process for the final phase of the task remains in S18, the process returns to S11 and the control process (S11 to S18) for the next phase is performed. In S18, when the control process for the final phase of the task is performed, the current control process is terminated.

  Here, an example of actual operation (phases A1 to A5) is illustrated, the signal change of each element is shown, and the operation by the control process of S19 is described with reference to FIGS. 11 and 12A to 12E. To do.

FIG. 11 is a diagram illustrating an operation process of phases A1 to A5 as an example of the operation.
As shown in FIG. 11, phases A1, A2, A3, and A4 are normal operation processes (task A) in which the wearer 12 shifts from the seated state to the away state. Phase A1 shows a state in which the wearer 12 is seated, phase A2 shows a state in which the wearer 12 leans forward, phase A3 shows a state in which the wearer 12 is in the middle, and phase A4 shows a state in which the wearer 12 has stood up.

  Phases A1, A2, A3, and A5 are irregular operations when the wearer 12 stops the rising operation in the middle waist state during the transition from the seated state to the seated state and returns from the middle waist state to the seated state. It is a process. Phase A1 shows a state in which the wearer 12 is seated, phase A2 shows a state in which the wearer 12 is leaning forward, phase A3 shows a state in which the wearer 12 is in the middle, and phase A5 shows a state in which the wearer 12 is seated.

  FIG. 12 is a graph of each signal corresponding to phases A1 to A5, where (A) is a graph showing changes in the angle of the knee joint, (B) is a graph showing changes in the reference parameters, and (C) is a measured myoelectric potential value. (D) is a graph showing the change of the difference ΔEMG (= EMGop−EMGex), and (E) is a graph showing the change of the gain P.

  As shown in FIG. 12A, a graph I (shown by a solid line) shows a knee joint angle (θknee) when the wearer 12 performs a normal operation of shifting from a seated state to a seated state. II (indicated by a broken line) indicates a knee joint angle (θknee) when the wearer 12 stops the standing-up motion in the middle waist state during the transition from the seated state to the away state and returns from the middle waist state to the seated state.

  From this graph I, it can be seen that the joint angle opens from 90 degrees to 110 degrees to 180 degrees when the operation is performed from phase A3 (center waist state) to phase A4 (rise state). Further, according to the graph II, when the operation is performed from the phase A3 (the middle waist state) to the phase A5 (the seated state), the joint angle is decreased again after the joint angle is changed from 90 degrees to 110 degrees to about 140 degrees. It can be seen that the degree returns to 110 degrees.

  As shown in FIG. 12B, graph III shows changes in the reference parameter (EMGop) corresponding to the normal operation process (phases A1 to A4) in which the wearer 12 shifts from the seated state to the away state. ing.

  As shown in FIG. 12 (C), graph IV (shown by a solid line) shows the measured value (EMGex) of the myoelectric potential when the wearer 12 performs a normal operation of shifting from the seated state to the away state. A graph V (shown by a broken line) shows a change in myoelectric potential when the wearer 12 stops the rising motion in the middle waist state during the transition from the seated state to the seated state and returns from the middle waist state to the seated state. The change in the actual measurement value (EMGex) is shown. From this graph V, it is understood that the myoelectric potential (EMGex) is lowered when the wearer 12 moves from the middle waist state to the seated state.

  As shown in FIG. 12D, a graph VI (shown by a solid line) shows a difference ΔEMG (= EMGop−EMGex) when the wearer 12 performs a normal operation of shifting from the seated state to the away state. Graph VII (shown by a broken line) shows a difference ΔEMG (when the wearer 12 stops the rising motion in the middle waist state during the transition from the seated state to the seated state and returns from the middle waist state to the seated state) = EMGop-EMGex). When the graph VI and the graph VII are compared, the difference ΔEMG of the graph VI changes below the allowable value H. In the graph VII, as the wearer 12 moves from the middle waist state to the seated state, the difference ΔEMG is It can be seen that the value has changed to a value exceeding the allowable value H.

  Therefore, the difference ΔEMG changes so that the measured value (EMGex) of the myoelectric potential shown in the graph V decreases and increases, and the myoelectric potential signal detected from the wearer 12 and the knee joint angle (θknee) are changed. It can be seen that the difference from the corresponding biological signal reflects the change in the measured value (EMGex) of the myoelectric potential.

  As shown in FIG. 12E, a graph VIII (shown by a solid line) shows a change in gain P when the wearer 12 performs a normal operation of shifting from the seated state to the away state, and graph IX (Shown by a broken line) shows a change in gain P when the wearer 12 stops the standing-up operation in the middle waist state during the transition from the seated state to the away state and returns from the middle waist state to the seated state.

  In this graph VIII, it can be seen that the gain P corresponding to the movement of each of the phases A1 to A4 (see FIG. 11) is generated, and in the graph IX, the gain P is reduced as the measured value of EMG (EMGex) decreases. It can be seen that the correction has been reduced.

  When this graph VIII is compared with the graph IX, the gain P changes in the graph VIII in substantially the same manner as the reference parameter (EMGop) shown in FIG. 12B, whereas in the graph IX, the gain P changes in FIG. It can be seen that the gain P decreases as in the graph V of the measured value (EMGex) of the myoelectric potential shown in FIG. Accordingly, when the difference ΔEMG shown in FIG. 12D exceeds the allowable value H, the muscle strength is weakened because the wearer 12 stops the normal standing motion and moves from the middle waist state to the seated state. Since the gain P is corrected so as to follow the change in the muscular strength, the wearer 12 can perform the seating operation smoothly as the assist force decreases.

  In this way, the control device 100 performs autonomous control that performs gain generation based on the reference parameter (EMGop) obtained based on the detected value (θknee) of the knee joint angle and the measured value (EMGex) of the myoelectric potential, and the wearer 12. A combination of voluntary control that reflects the intention of the wearer 12 by correcting the gain when the difference between the myoelectric signal detected from the signal and the biological signal corresponding to the knee joint angle (θknee) exceeds the allowable value H. Thus, even when the wearer 12 changes the muscular strength during the operation before the end of the series of phases, it is possible to control the wearer 12 so as not to interfere with the operation by reducing the assist force. It is possible to prevent an assist force that is contrary to the intention of the wearer 12 from being applied.

  In the above-described embodiment, the motion assisting device 10 configured to apply the assist force to the leg of the wearer 12 is described as an example. However, the present invention is not limited to this. For example, the motion assisting device 10 is configured to assist the arm motion. Of course, the present invention can also be applied to other motion assisting devices.

  In the above-described embodiment, the configuration in which the drive torque of the electric motor is transmitted as the assist force has been described. However, the present invention can be applied to a device that generates the assist force using a drive source other than the electric motor. is there.

It is a block diagram which shows the control system applied to one Example of the mounting | wearing type movement assistance apparatus which becomes this invention. It is the perspective view which looked at the state by which one Example of the mounting | wearing type movement assistance apparatus which becomes this invention was mounted | worn from the front side. It is the perspective view which looked at the state with which one Example of the mounting | wearing type movement assistance apparatus which becomes this invention was mounted | worn from the rear side. FIG. 6 is a left side view of the motion assisting wearing tool 18. FIG. 6 is a rear view of the motion assisting wearing tool 18. It is a block of each apparatus which comprises the movement assistance apparatus 10. FIG. It is a figure which shows an example of each task and phase stored in the reference | standard parameter database. It is the figure which showed the reference | standard parameter database 148 typically. It is the figure which showed command signal database 150 typically. 4 is a flowchart for illustrating a procedure of control processing executed by control device 100. It is a figure which shows the operation | movement process of phase A1-A5 as an example of operation | movement. It is a graph of each element corresponding to phase A1-A5, (A) is a graph which shows the angle change of a knee joint, (B) is a graph which shows the change of a reference parameter, (C) is a change of an electromyogram measured value. (D) is a graph showing the change of the difference ΔEMG (= EMGop−EMGex), and (E) is a graph showing the change of the gain P.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Movement assistance apparatus 12 Wearer 20 Right thigh drive motor 22 Left thigh drive motor 24 Right knee drive motor 26 Left knee drive motor 30 Lumbar belt 32, 34 Battery 36 Control back 38a, 38b, 40a, 40b, 42a, 42b, 44a 44b EMG sensor 50a, 50b, 52a, 52b Reaction force sensor 54 Right leg auxiliary part 55 Left leg auxiliary part 56 1st frame 58 2nd frame 60 3rd frame 62 4th frame 64 1st joint 66 2nd joint 70 , 72, 74, 76 Angle sensor 78 First fastening belt 80 Second fastening belt 84 Wedge receiving portion 86 Power supply circuit 88 Input / output interface 100 Control devices 101 to 108 Differential amplifiers 111 to 114 Angle detection portions 121 to 124 Reaction force detection Unit 130 memory 140 drive source 142 physical phenomenon detection means 144 biological signal detection means 1 6 data storage means 148 reference parameter database 150 the command signal database 152 phase identification unit 154 difference deriving unit 158 power amplifier means 160 autonomously control means

Claims (8)

A wearable movement assist device that assists or acts on behalf of the wearer,
A motion assisting wearing device having a drive source for applying power to the wearer;
First detection means for detecting an angle of a joint of the wearer according to the operation of the wearer;
Second detection means for detecting a biological signal associated with the muscle activity of the wearer;
Storage means for storing a reference parameter consisting of a data group in which the joint angle and biological signal of the wearer are set so as to correspond to each of a series of phases constituting the wearer's operation pattern;
Phase identification means for identifying the phase of the wearer's movement pattern by comparing the joint angle detected by the first detection means with the joint angle of the reference parameter ;
A command signal is generated for causing the drive source to generate power according to the phase specified by the phase specifying means, and the drive source is controlled to assist an operation pattern according to the wearer's intention. Autonomous control means,
Whether or not the difference between the biological signal of the reference parameter corresponding to the joint angle detected by the first detecting means and the biological signal detected by the second detecting means exceeds a preset allowable value. A judging means for judging;
Changing means for changing a command signal to be generated by the autonomous control means according to the difference when the determination means determines that the difference exceeds the allowable value;
A wearable movement assist device characterized by comprising:   The changing unit is configured to switch the autonomous control unit when the biological signal of the reference parameter corresponding to the joint angle detected by the first detecting unit is larger than the biological signal detected by the second detecting unit. The wearable motion assisting device according to claim 1, wherein the command signal to be generated is reduced. The movement assist wearing device is:
Waist belt,
A right leg auxiliary part provided below from the right side of the waist belt;
A left leg auxiliary part provided below from the left side of the waist belt;
Have
The right leg auxiliary part and the left leg auxiliary part are
A first frame extending downward to support the waist belt;
A second frame extending below the first frame;
A third frame extending below the second frame;
A fourth frame provided at the lower end of the third frame, on which the back of the leg of the wearer is placed;
A first joint interposed between a lower end of the first frame and an upper end of the second frame;
A second joint interposed between a lower end of the second frame and an upper end of the third frame;
The wearable motion assisting device according to claim 1, comprising: The first joint is provided at a height position that matches the hip joint of the wearer,
The wearable motion assisting device according to claim 3, wherein the second joint is provided at a height position coinciding with the knee joint of the wearer. The first joint is provided with a first driving source that transmits a driving force so as to rotate the second frame,
5. The wearable movement assist device according to claim 3, wherein the second joint is provided with a second drive source that transmits a driving force so as to rotate the third frame. 6.   The wearable motion assisting device according to claim 5, wherein the first and second driving sources include angle sensors that detect joint angles. A driving source that generates power for assisting or acting on the wearer's movement, first detection means for detecting the angle of the joint of the wearer according to the movement of the wearer, and muscle activity of the wearer In a method for controlling the drive source in a wearable motion assisting device comprising second detection means for detecting a biological signal involved and an autonomous control means for generating a command signal for generating power in the drive source. There,
A first step of previously storing in the storage means a reference parameter consisting of a data group in which the wearer's joint angle and biological signal are set so as to correspond to each of a series of phases constituting the wearer's motion pattern;
A second step of identifying the phase of the wearer's movement pattern by comparing the joint angle detected by the first detection means with the joint angle of the reference parameter ;
The autonomous control means generates a command signal for causing the drive source to generate power corresponding to the identified phase, and the drive source is controlled to assist the operation pattern according to the wearer's intention. and a third step you,
Whether or not the difference between the biological signal of the reference parameter corresponding to the joint angle detected by the first detecting means and the biological signal detected by the second detecting means exceeds a preset allowable value. A fourth step of determining;
And a fifth step of changing a command signal to be generated by the autonomous control means according to the difference when the difference exceeds the allowable value. Control method.   A program that causes a computer to execute the control method according to claim 7.

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