Electrical stimulation device, program, and electrical stimulation method

Abstract

To provide an electrostimulator capable of improving disturbance suppression characteristics.SOLUTION: An electrostimulator includes a signal generation unit, a detection unit, and a disturbance calculation unit. The signal generation unit generates an electric stimulation signal for controlling electric stimulation to a muscle. The detection unit detects actual information on an actual motion of a muscle. The disturbance calculation unit calculates disturbance information on the basis of the actual information in a case where the electric stimulation based on the electric stimulation signal is applied to the muscle, and estimation information indicating a result of the estimation on the motion of the muscle in a case where the electric stimulation based on the electric stimulation signal is applied to the muscle. The disturbance information indicates an influence given to the actual information by the disturbance. The signal generation unit generates the electric stimulation signal on the basis of the disturbance information calculated by the disturbance calculation unit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to an electrical stimulation device, a program, and an electrical stimulation method. [Background technology]

[0002] There is known a technique for electrically stimulating the muscles of a human or animal to move the muscles (for example, Patent Document 1). For example, Patent Document 1 describes a technique for generating an electrical stimulation signal for controlling the electrical stimulation to the muscles, and controlling the movement of the muscles by the electrical stimulation based on the generated electrical stimulation signal. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-23223 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is considered that feedback control of electrical stimulation signals can be used to make the muscles of a living organism perform desired movements. "Living organisms" include, for example, humans and animals. Electrical stimulation causes muscles to contract. As a result, parts of the living organism move in conjunction with the muscles that have been electrically stimulated. It is considered that this can be used to rehabilitate and assist the functions of paralyzed patients, as well as to make the living organism perform desired tasks through external operation. For example, PID control is being considered as feedback control.

[0005] When controlling the movement of a living organism using electrical stimulation signals, external forces are applied to the muscles of the organism in accordance with the movement. Hereinafter, the forces applied to the muscles of the organism from the outside are referred to as "disturbances." However, feedback control using PID control or the like alone has limitations in terms of both improving the tracking characteristics of moving a part of the organism to a target position using electrical stimulation and improving the disturbance suppression characteristics. Unless disturbance suppression characteristics are ensured in addition to tracking characteristics, it is difficult to achieve advanced movement control in a living organism due to limitations in motion control performance.

[0006] It is conceivable to perform force control, impedance control, compliance control, and the like by electrically stimulating muscles of a living body. However, when realizing such control with low servo stiffness, it is expected that the gain of the PID control will be reduced. If the gain of the PID control is reduced, the disturbance suppression characteristic will also be reduced accordingly. Taking these points into consideration, the inventor of the present application has studied control that takes into account the disturbance suppression characteristic in addition to the tracking characteristic in controlling the movement of muscles by electrical stimulation signals.

[0007] An object of one aspect of the present invention is to provide an electrical stimulation device capable of improving disturbance suppression characteristics.An object of another aspect of the present invention is to provide a program capable of improving disturbance suppression characteristics.An object of yet another aspect of the present invention is to provide an electrical stimulation method capable of improving disturbance suppression characteristics. [Means for solving the problem]

[0008] An electrical stimulation device according to one aspect of the present invention includes a signal generating unit, a detecting unit, and a disturbance calculating unit. The signal generating unit generates an electrical stimulation signal for controlling electrical stimulation to a muscle. The detecting unit detects actual information relating to actual muscle movement. The disturbance calculating unit calculates disturbance information based on actual information and estimated information indicating an estimated result of muscle movement when electrical stimulation based on the electrical stimulation signal is applied to the muscle. The disturbance information indicates the effect of a disturbance on the actual information. The signal generating unit generates the electrical stimulation signal based on the disturbance information calculated by the disturbance calculating unit.

[0009] In one of the above aspects, the disturbance calculation unit calculates disturbance information indicating the effect of the disturbance on the actual information based on actual information on the actual muscle movement and estimated information indicating the estimated result of the muscle movement. The signal generation unit generates an electrical stimulation signal based on the disturbance information calculated by the disturbance calculation unit. In this way, in the electrical stimulation device, disturbance information on the force applied to the muscle from the outside is calculated, and the electrical stimulation signal is generated based on the calculated disturbance information. As a result, the disturbance suppression characteristic against the force applied to the muscle from the outside is improved. In other words, robustness can be ensured even in a situation where a force is applied to the muscle from the outside.

[0010] In one of the above aspects, the disturbance calculation unit may calculate the estimated information based on a muscle model and the electrical stimulation signal generated by the signal generation unit. The muscle model is a model that outputs the estimated information by inputting information related to the electrical stimulation signal. The disturbance calculation unit may calculate, as the disturbance information, information indicating a difference between the calculated estimated information and information related to the actual information detected by the detection unit. In this case, the disturbance information can be calculated more accurately.

[0011] In one of the above aspects, the signal generating unit may acquire command information, actual information, and disturbance information. The command information indicates a target value related to muscle movement. The signal generating unit may generate an electrical stimulation signal based on the command information, actual information, and disturbance information. In this case, since the signal generating unit generates the electrical stimulation signal based on both the command information and the actual information, it is possible to more reliably achieve both the tracking characteristic and the disturbance suppression characteristic. For example, the signal generating unit may perform feedback control based on the command information and the actual information.

[0012] In the above-mentioned one aspect, the signal generating unit may include a difference acquiring unit and a control information generating unit. The difference acquiring unit may acquire difference information indicating a difference between the command information and the actual information. The control information generating unit may generate control information for generating the electrical stimulation signal based on the difference information. The signal generating unit may generate the electrical stimulation signal based on the control information and the disturbance information. In this case, the tracking characteristic can be ensured by generating the control information. Since the electrical stimulation signal is generated based on the control information and the disturbance information after the control information is generated, it is possible to more easily and reliably achieve both the securing of the tracking characteristic and the securing of the disturbance suppression characteristic.

[0013] In one embodiment, the muscle may include an extensor muscle and a flexor muscle. The electrical stimulation signal may include a first electrical stimulation signal that controls electrical stimulation to the extensor muscle and a second electrical stimulation signal that controls electrical stimulation to the flexor muscle. The relationship between muscle contraction of the extensor muscle and the flexor muscle is closely related to the movement of the joint. By controlling the movement of the extensor muscle and the movement of the flexor muscle by the electrical stimulation signal, the movement of the living body can be controlled more accurately and naturally.

[0014] In one aspect, the signal generating unit may include a pulse generating unit that generates a first and a second pulse signal. The first pulse signal may correspond to a first electrical stimulation signal. The second pulse signal may correspond to a second electrical stimulation signal. The pulse generating unit may acquire total information corresponding to a sum of the first pulse signal and the second pulse signal, and difference information corresponding to a difference between the first pulse signal and the second pulse signal. The pulse generating unit may generate the first pulse signal and the second pulse signal based on the acquired total information and difference information. In this case, the movement of the extensor and flexor muscles can be controlled to a higher degree.

[0015] In the above-mentioned aspect, the electrical stimulation signal may be a pulse signal, and the signal generating unit may set a pulse width of the electrical stimulation signal in response to the disturbance information. In this case, the muscle movement can be more reliably controlled by the electrical stimulation signal.

[0016] In the above aspect, the electrical stimulation device may further include a conversion unit. The conversion unit converts the disturbance information into pulse information corresponding to the pulses of the electrical stimulation signal. The signal generation unit may set a pulse width of the electrical stimulation signal based on the disturbance information converted by the conversion unit. In this case, since the electrical stimulation signal is directly corrected based on the disturbance information, the disturbance suppression characteristic can be further improved.

[0017] In one of the above aspects, the electrical stimulation device may further include a feedforward control unit. The feedforward control unit performs feedforward control based on command information indicating a target value for muscle movement. The signal generating unit may generate an electrical stimulation signal based on information output from the feedforward control unit. In this case, the feedforward control unit may also perform control taking disturbance into consideration. If a certain degree of disturbance suppression characteristics is ensured by the feedforward control unit, the accuracy of muscle movement relative to the command information may be further improved by generating an electrical stimulation signal based on the disturbance information calculated by the disturbance calculation unit. It is possible to reduce the influence of disturbance in position control based on the output information from the feedforward control unit, and to reduce the influence of disturbance in force control based on the disturbance information calculated by the disturbance calculation unit.

[0018] In one of the above aspects, the command information indicating a target value for the muscle motion may include position information for the muscle motion and force information for the muscle motion. The signal generating unit may modify the force information based on the disturbance information. The signal generating unit may generate an electrical stimulation signal based on the position information and the modified force information. In this case, the disturbance suppression characteristic for the force generated in the muscle may be improved while the tracking characteristic is ensured based on the displacement information. Therefore, the motion in which the living body receives a reaction force from an external object, such as gripping an object, may be more accurately performed.

[0019] In the above aspect, the signal generator may set an impedance in the impedance control or a compliance in the compliance control based on the disturbance information. The signal generator may generate an electrical stimulation signal based on the set impedance or compliance. In this case, in controlling the movement of a muscle by electrical stimulation, impedance control or compliance control can be performed more appropriately taking into account a force applied to the muscle from the outside.

[0020] A program according to another aspect of the present invention causes a computer to acquire actual information, acquire estimated information, calculate disturbance information based on the actual information and the estimated information, and generate an electrical stimulation signal based on the disturbance information. The actual information relates to actual muscle movement. The estimated information indicates an estimated result of muscle movement when electrical stimulation based on the electrical stimulation signal is applied to the muscle. The disturbance information indicates an effect of the disturbance on the actual information.

[0021] In the above-mentioned another aspect, disturbance information indicating the effect of a disturbance on the actual information is calculated based on actual information regarding the actual muscle motion and estimated information indicating an estimated result of the muscle motion. The electrical stimulation signal is generated based on the disturbance information. As a result, disturbance suppression characteristics against a force applied to the muscle from the outside are improved. In other words, robustness can be ensured even in a situation where a force is applied to the muscle from the outside.

[0022] In yet another aspect of the present invention, an electrical stimulation method includes acquiring actual information, acquiring estimated information, calculating disturbance information based on the actual information and the estimated information, generating an electrical stimulation signal based on the disturbance information, and applying electrical stimulation to a muscle based on the generated electrical stimulation signal. The actual information relates to actual muscle movement. The estimated information indicates an estimated result of muscle movement when electrical stimulation based on the electrical stimulation signal is applied to the muscle. The disturbance information indicates an effect of the disturbance on the actual information.

[0023] In yet another aspect of the present invention, disturbance information indicating the effect of a disturbance on actual information is calculated based on actual information regarding actual muscle motion and estimated information indicating an estimated result of muscle motion. An electrical stimulation signal is generated based on the disturbance information. As a result, muscle motion can be controlled in a state in which disturbance suppression characteristics against a force applied to the muscle from the outside are improved. In other words, even in a situation in which a force is applied to the muscle from the outside, muscle motion can be controlled in a state in which robustness is ensured. Effect of the Invention

[0024] According to one aspect of the present invention, there is provided an electrical stimulation device capable of improving disturbance suppression characteristics. According to another aspect of the present invention, there is provided a program capable of improving disturbance suppression characteristics. According to yet another aspect of the present invention, there is provided an electrical stimulation method capable of improving disturbance suppression characteristics. [Brief description of the drawings]

[0025] [Figure 1] 1 is a block diagram of an electrical stimulation device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic diagram of the controls performed in the electrical stimulation device. [Diagram 3] FIG. 2 is a diagram illustrating an example of a hardware configuration of a main body of an electrical stimulation device. [Figure 4] FIG. 13 is a block diagram of an electrical stimulation device according to a modified example of the embodiment. [Diagram 5] FIG. 13 is a schematic diagram of control performed in an electrical stimulation device according to a modified example of the present embodiment. [Figure 6] FIG. 13 is a block diagram of an electrical stimulation device according to another modified example of the embodiment. [Figure 7] 13 is a schematic diagram of control performed in an electrical stimulation device according to another modified example of the present embodiment. FIG. [Figure 8] FIG. 1 is a schematic diagram of the experimental setup. [Figure 9] FIG. 13 is a diagram showing a disturbance signal input to the experimental apparatus. [Figure 10]FIG. 4A is a diagram showing experimental results of a comparative example, and FIG. 4B is a diagram showing experimental results of the electrical stimulation device of the present embodiment. [Figure 11] FIG. 13 is a diagram showing a control signal input to the experimental device. [Figure 12] FIG. 4A is a diagram showing experimental results of a comparative example, and FIG. 4B is a diagram showing experimental results of the electrical stimulation device of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of an electrical stimulation device according to the present invention will be described in detail with reference to the drawings. In the description of the drawings, the same or corresponding parts are given the same reference numerals, and duplicated description will be omitted. First, with reference to FIG. 1, a schematic configuration of an electrical stimulation device according to an embodiment of the present invention will be described. FIG. 1 is a block diagram of an electrical stimulation device in this embodiment. In FIG. 1, solid lines connecting blocks indicate electrical connections between blocks in this embodiment.

[0027] The electrical stimulation device 1 assists or controls biological functions by providing electrical stimulation to the muscles of a living organism. The electrical stimulation device 1 includes a so-called functional electrical stimulation device. The muscles to which the electrical stimulation device 1 provides electrical stimulation include, for example, extensor muscles and flexor muscles. The electrical stimulation device 1 controls the movement of the muscles of a living organism, for example, by providing electrical stimulation to the muscles. The electrical stimulation to the muscles includes providing electrical stimulation to the nervous system involved in the movement of the muscles. The electrical stimulation device 1 includes an electrical stimulation unit 2, a detection unit 3, and a main body unit 4. The electrical stimulation unit 2 and the detection unit 3 are connected to the main body unit 4 by wire or wirelessly. For example, the electrical stimulation unit 2 and the detection unit 3 are electrically connected to the main body unit 4.

[0028] The electrical stimulation unit 2 is attached to a living body and provides electrical stimulation to the muscles of the living body. By applying an electric potential to the electrical stimulation unit 2, a current flows through the living body to which the electrical stimulation unit 2 is attached. For example, the electrical stimulation unit 2 includes a pair of pads, and the pair of pads are attached to the skin of the living body. The electrical stimulation unit 2 is attached to the forearm, for example.

[0029] The electrical stimulation unit 2 passes an electric current between the pair of pads through the living body based on the electrical stimulation signal output from the main body unit 4. As a result, an electrical stimulation is given to the muscle through the skin. The electrical stimulation signal is a signal that controls the electrical stimulation to the muscle. The electrical stimulation signal is, for example, a pulse signal. The timing of the electric current passed between the pads by the electrical stimulation unit 2 is synchronized with the electrical stimulation signal. The pulse width of the electrical stimulation signal corresponds to the intensity of the electrical stimulation by the electrical stimulation unit 2.

[0030] The detection unit 3 detects actual information and outputs the detected actual information. "Actual information" is information relating to actual muscle movement. "Information relating to actual muscle movement" includes at least one of information indicating the movement of the muscle itself and information indicating the movement of a part of a living body linked to the muscle movement. Information indicating the movement of the muscle itself includes, for example, myoelectricity.

[0031] The detection unit 3 detects, for example, the movement of a part of the living body linked to the movement of a muscle due to electrical stimulation from the electrical stimulation unit 2 as actual information. The detection unit 3 detects, for example, the position of the part of the living body. In this embodiment, the detection unit 3 detects the angle at which a joint moves by applying an electrical stimulation signal to a muscle. For example, the detection unit 3 detects the angle at which a wrist joint moves. The detection unit 3 may detect, for example, a force generated in a part of the living body, an acceleration generated in a part of the living body, or a force applied to an object when the living body touches the object.

[0032] The detection unit 3 includes a sensor that detects the movement of a part of the living body. The detection unit 3 includes, for example, a motor that outputs information on a rotation angle and a rotation torque as a sensor. The detection unit 3 may include a rotary encoder as a sensor. The detection unit 3 may include an optical, electrostatic, or pressure-sensitive sensor. The sensor of the detection unit 3 is attached to, for example, a part of the living body. As a variation of this embodiment, the detection unit 3 may be separated from the part of the living body. In this case, the detection unit 3 detects the movement of the living body by, for example, motion capture.

[0033] The main body 4 generates the electrical stimulation signal for operating the electrical stimulation unit 2. The main body 4 includes one or more computers. The main body 4 includes a goal determination unit 11, a stimulation signal generation unit 12, a disturbance calculation unit 13, a model storage unit 14, and a disturbance information conversion unit 15.

[0034] The target determination unit 11 determines a target value for muscle movement. For example, the target determination unit 11 determines a target value based on a command obtained from the outside. For example, the target determination unit 11 outputs command information indicating the determined target value to the stimulation signal generation unit 12. The "target value for muscle movement" includes at least one of a target value for muscle movement and a target value for the movement of a part of a living body linked to the muscle movement. For example, the target value determined by the target determination unit 11 is a position to which a part of a living body is moved in conjunction with the muscle movement, a displacement of a muscle due to contraction, a force generated in a muscle, and a force generated in a part of a living body according to the muscle movement.

[0035] The "command information" includes at least one of position information related to muscle movement and force information related to muscle movement. The force information corresponds to torque information indicating torque. The torque information is, for example, a torque value. The "position information related to muscle movement" includes at least one of information indicating a position at which a part of a living body is moved in conjunction with muscle movement and information indicating a displacement of a muscle due to contraction. The "force information related to muscle movement" includes at least one of information indicating a force generated in a muscle and information indicating a force generated in a part of a living body according to muscle movement. The "position at which a part of a living body is moved in conjunction with muscle movement" is, for example, an angle at which a joint is moved. The "force generated in a part of a living body according to muscle movement" includes, for example, at least one of an acceleration generated in a part of a living body and a force applied to an object when the living body touches the object. In this embodiment, the target determination unit 11 outputs, as the command information, an angle command value indicating an angle at which the joint is moved. As a modified example of this embodiment, the target determination unit 11 may output, as the command information, a torque command value indicating a torque to be generated in a muscle.

[0036] The stimulation signal generating unit 12 generates the electrical stimulation signal based on the actual information detected by the detecting unit 3, the command information output from the target determining unit 11, and the disturbance information output from the disturbance calculating unit 13. The "disturbance information" is information related to a disturbance, and is information indicating the effect of the disturbance on the actual information detected by the detecting unit 3. The stimulation signal generating unit 12 generates an electrical stimulation signal so that the value of the disturbance information becomes zero, for example. The stimulation signal generating unit 12 sets a pulse width of the electrical stimulation signal based on the actual information, the command information, and the disturbance information, for example. The stimulation signal generating unit 12 outputs the generated electrical stimulation signal to the electrical stimulation unit 2 and the disturbance calculating unit 13. The stimulation signal generating unit 12 includes a first adding and subtracting unit 21, a control information generating unit 22, a second adding and subtracting unit 23, a pulse generating unit 24, and a third adding and subtracting unit 25.

[0037] The first addition / subtraction unit 21 performs a calculation based on the actual information detected by the detection unit 3 and the command information output from the target determination unit 11. For example, the first addition / subtraction unit 21 calculates a difference between the actual information detected by the detection unit 3 and the command information output from the target determination unit 11. For example, the first addition / subtraction unit 21 calculates a deviation by subtracting the actual information output from the detection unit 3 from the command information output from the target determination unit 11. In other words, the first addition / subtraction unit 21 calculates a control deviation in feedback control. For example, the first addition / subtraction unit 21 acquires difference information indicating the difference between the actual information detected by the detection unit 3 and the command information output from the target determination unit 11, and outputs it to the control information generation unit 22. The first addition / subtraction unit 21 corresponds to a difference acquisition unit.

[0038] The control information generating unit 22 generates control information for generating an electrical stimulation signal based on the actual information detected by the detection unit 3 and the command information output from the target determination unit 11. The control information generating unit 22 generates control information based on the difference information output from the first addition / subtraction unit 21. As a result, feedback control is performed. The feedback control is executed by the first addition / subtraction unit 21 and the control information generating unit 22. The control information generating unit 22 performs PID control, for example, based on the difference information output from the first addition / subtraction unit 21. "Control information" is a control input. In this specification, "PID control" includes control by only P operation, control by only I operation, and control combining at least one of I operation and D operation with P operation. The control information generating unit 22 outputs the calculation result based on the PID control to the second addition / subtraction unit 23.

[0039] In this embodiment, the main body 4 further includes a feedforward control unit 16. The feedforward control unit 16 performs feedforward control based on command information output from the target determination unit 11. The feedforward control unit 16 estimates information about disturbances based on command information output from the target determination unit 11 as feedforward control. The feedforward control unit 16 estimates, for example, the influence of disturbances among the output of PID control based on actual information output from the detection unit 3 as information about disturbances. In this embodiment, the feedforward control unit 16 performs feedback control by a transfer function corresponding to command information determined in advance. The feedforward control unit 16 may perform feedback control based on disturbances detected by a detection unit provided separately from the detection unit 3, for example. The feedforward control unit 16 outputs the calculation result based on the feedforward control to the second addition / subtraction unit 23.

[0040] As a modification of this embodiment, the main body 4 may not include the feedforward control unit 16. In this case, the stimulation signal generating unit 12 may not include the second adding / subtracting unit 23. In this case, the control information generating unit 22 outputs, for example, a calculation result based on PID control to the pulse generating unit 24.

[0041] In this embodiment, the second addition / subtraction unit 23 performs calculation based on the control information output from the control information generation unit 22 and the information output from the feedforward control unit 16. For example, the second addition / subtraction unit 23 calculates the difference between the calculation result based on the PID control and the calculation result based on the feedforward control. For example, the second addition / subtraction unit 23 calculates the deviation by subtracting the calculation result based on the feedforward control from the calculation result based on the PID control. For example, the second addition / subtraction unit 23 outputs information indicating the difference between the calculation result based on the PID control and the calculation result based on the feedforward control to the pulse generation unit 24 as new control information.

[0042] The pulse generating unit 24 generates a pulse signal based on the control information output from the control information generating unit 22. This pulse signal corresponds to an electrical stimulation signal. The pulse generating unit 24 generates a pulse signal based on, for example, the control information output from the control information generating unit 22 and information output from the feedforward control unit 16. The pulse generating unit 24 generates a pulse signal based on, for example, the information output from the second adding / subtracting unit 23. The pulse generating unit 24 outputs the generated pulse signal to the third adding / subtracting unit 25.

[0043] The pulse generating unit 24 generates, for example, a first pulse signal and a second pulse signal. The first pulse signal corresponds to a first electrical stimulation signal that controls electrical stimulation to an extensor muscle among electrical stimulation signals. The second pulse signal corresponds to a second electrical stimulation signal that controls electrical stimulation to a flexor muscle among electrical stimulation signals. The pulse generating unit 24 generates the first pulse signal and the second pulse signal based on total information corresponding to the sum of the first pulse signal and the second pulse signal and difference information corresponding to the difference between the first pulse signal and the second pulse signal. The pulse generating unit 24 acquires the total information and the difference information from, for example, the model storage unit 14 or a storage unit not shown. The pulse generating unit 24 may calculate the total information and the difference information based on, for example, command information.

[0044] The third addition / subtraction unit 25 performs calculation based on the information on the pulse signal output from the pulse generation unit 24 and the disturbance information output from the disturbance calculation unit 13. For example, the third addition / subtraction unit 25 adds the pulse information on the pulse signal output from the pulse generation unit 24 and the disturbance information output from the disturbance information conversion unit 15. The third addition / subtraction unit 25 outputs a pulse signal. In the third addition / subtraction unit 25, the pulse information of the pulse signal output from the pulse generation unit 24 is changed according to the disturbance information output from the disturbance information conversion unit 15. The disturbance information output from the disturbance information conversion unit 15 is related to the disturbance information output from the disturbance calculation unit 13. The "pulse information" is, for example, a pulse width. In other words, in the third addition / subtraction unit 25, the pulse width of the electrical stimulation signal is set based on the disturbance information output from the disturbance information conversion unit 15. The pulse signal output from the third addition / subtraction unit 25 is input to the disturbance calculation unit 13 and the electrical stimulation unit 2 as an electrical stimulation signal.

[0045] In this manner, the stimulation signal generating unit 12 generates the electrical stimulation signal based on the disturbance information output from the disturbance information converting unit 15. In this embodiment, the stimulation signal generating unit 12 generates the electrical stimulation signal based on pulse information regarding a pulse signal generated based on the control information output from the control information generating unit 22 and the disturbance information output from the disturbance information converting unit 15. In other words, the stimulation signal generating unit 12 generates the electrical stimulation signal based on the control information and the disturbance information. The stimulation signal generating unit 12 outputs the generated electrical stimulation signal to the electrical stimulation unit 2 and the disturbance computing unit 13.

[0046] The disturbance calculation unit 13 acquires the electrical stimulation signal output from the stimulation signal generation unit 12 and the actual information detected by the detection unit 3, and calculates disturbance information based on the electrical stimulation signal and the actual information. The disturbance calculation unit 13 includes a so-called disturbance observer. The disturbance calculation unit 13 calculates estimated information based on the electrical stimulation signal output from the stimulation signal generation unit 12. The "estimated information" is information indicating an estimated result of the movement of a muscle when an electrical stimulation based on the electrical stimulation signal is applied to the muscle. The disturbance calculation unit 13 calculates and outputs disturbance information based on the calculated estimated information and the actual information detected by the detection unit 3. The disturbance calculation unit 13 calculates information indicating the difference between the calculated estimated information and information on the actual information detected by the detection unit 3 as disturbance information. The "information on the actual information" includes at least one of the actual information itself and information obtained by converting the actual information detected by the detection unit 3 into the same format as the estimated information.

[0047] The model storage unit 14 stores information about the muscle model in advance. The muscle model includes, for example, a transfer function. The model storage unit 14 stores, for example, a transfer function as information about the muscle model. The muscle model outputs estimated information by inputting information about the electrical stimulation signal. The "information about the electrical stimulation signal" includes at least one of the electrical stimulation signal itself and information indicating the state of the electrical stimulation signal. The "input of information about the electrical stimulation signal" is, for example, an input of pulse information indicated by the electrical stimulation signal. The muscle model outputs estimated information by, for example, integrating the input of information about the electrical stimulation signal and the transfer function of a first-order lag system. The transfer function included in the muscle model is, for example, expressed by "K / (1+Ts)" when the gain is "K", the time constant is "T", and the parameter in the Laplace transform is "s". When the pulse information of the electrical stimulation signal is input to this muscle model, torque information generated in the muscle is output. In addition to the muscle model, the model storage unit 14 may store various information required by each functional unit in advance.

[0048] The disturbance information converter 15 converts the disturbance information output from the disturbance calculation unit 13 into a predetermined information format. The disturbance information converter 15 outputs the information obtained by converting the disturbance information to the third addition / subtraction unit 25. In this embodiment, the disturbance information converter 15 converts the disturbance information output from the disturbance calculation unit 13 into the same format as the pulse signal output from the pulse generation unit 24. In other words, the disturbance information converter 15 converts the disturbance information output from the disturbance calculation unit 13 from torque information into pulse information corresponding to the pulse of the electrical stimulation signal.

[0049] Next, a more detailed description will be given of the disturbance calculation unit 13. The disturbance calculation unit 13 includes an estimation unit 31, a detection information conversion unit 32, a fourth addition / subtraction unit 33, and a filter unit .

[0050] The estimation unit 31 calculates estimation information indicating an estimation result of a muscle movement when an electrical stimulus based on the electrical stimulus signal is applied to the muscle, based on the electrical stimulus signal generated by the stimulation signal generation unit 12, based on the muscle model. The estimation unit 31 obtains information on the muscle model from, for example, the model storage unit 14. The estimation unit 31 inputs information on the electrical stimulus signal to the muscle model, and outputs the estimation information.

[0051] The information on the electrical stimulation signal input to the muscle model is, for example, information output from the third addition / subtraction unit 25. The estimated information output by the muscle model indicates an estimated result of the muscle movement when an electrical stimulation based on the electrical stimulation signal input to the muscle model is applied to the muscle. The estimated information output by the muscle model indicates, for example, an estimated result of the torque by the muscle when an electrical stimulation based on the electrical stimulation signal input to the muscle model is applied to the muscle. The estimation unit 31 outputs, for example, the estimated information based on the information output from the third addition / subtraction unit 25 and the muscle model to the fourth addition / subtraction unit 33.

[0052] The detection information conversion unit 32 converts the actual information detected by the detection unit 3 into a predetermined information format. In this embodiment, the detection information conversion unit 32 converts the actual information detected by the detection unit 3 into the same format as the estimated information output from the estimation unit 31. Based on the actual information detected by the detection unit 3, the detection information conversion unit 32 calculates torque information indicating the torque actually generated in the muscle when an electrical stimulus based on an electrical stimulus signal is applied to the muscle. In this embodiment, the detection information conversion unit 32 calculates torque information indicating the torque actually generated in the muscle based on actual information regarding the angle at which the joint moves. The detection information conversion unit 32 outputs the value of the torque actually generated in the muscle by, for example, multiplying the input of actual information regarding the angle at which the joint moves by a predetermined transfer function. The predetermined transfer function is, for example, a function that converts nominal inertia into "J n " and the parameter in the Laplace transform is "s", then "J n s 2 The detected information conversion unit 32 converts the actual information detected by the detection unit 3 and outputs the converted information to the fourth addition / subtraction unit 33.

[0053] The fourth addition / subtraction unit 33 performs a calculation based on the estimated information output from the estimation unit 31 and information on the actual information. For example, the fourth addition / subtraction unit 33 calculates the difference between the estimated information output from the estimation unit 31 and information on the actual information. For example, the fourth addition / subtraction unit 33 calculates the difference between the estimated information output from the estimation unit 31 and information output from the detection information conversion unit 32. The information output from the detection information conversion unit 32 relates to the actual information detected by the detection unit 3. For example, the fourth addition / subtraction unit 33 calculates a deviation by subtracting the information output from the detection information conversion unit 32 from the estimated information output from the estimation unit 31. The fourth addition / subtraction unit 33 outputs information indicating the difference between the estimated information output from the estimation unit 31 and the information output from the detection information conversion unit 32 to the filter unit 34 as disturbance information.

[0054] The filter unit 34 filters the disturbance information output from the fourth addition / subtraction unit 33. The filter unit 34 removes noise from the disturbance information output from the fourth addition / subtraction unit 33. The filter unit 34 includes, for example, a low-pass filter. The information output from the fourth addition / subtraction unit 33 is input to the disturbance information conversion unit 15 as disturbance information via the filter unit 34. In this way, the disturbance calculation unit 13 outputs the calculated disturbance information to the disturbance information conversion unit 15.

[0055] Next, an example of an electrical stimulation method using the electrical stimulation device 1 will be described with reference to Figures 1 and 2. Figure 2 is a schematic diagram of control performed in the electrical stimulation device.

[0056] First, the target determination unit 11 determines the angle command value θ cmd The angle command value θ output from the target determination unit 11 cmd is input to the feedforward control unit 16 and the first addition / subtraction unit 21. The feedforward control unit 16 receives the angle command value θ cmd The first addition / subtraction unit 21 performs feedforward control based on the angle response value θ res and the angle command value θ cmd and calculates a difference between the difference between the input difference information and the feedback control difference information. The difference information calculated in the first addition / subtraction unit 21 is input to the control information generation unit 22. That is, the first addition / subtraction unit 21 calculates a control deviation of the feedback control and inputs it to the control information generation unit 22. The control information generation unit 22 executes PID control based on the input difference information, and outputs the control information to the second addition / subtraction unit 23. The control information is a control input. The control information generation unit 22 executes feedback control by executing PID control based on the input difference information.

[0057] The second adding / subtracting unit 23 calculates the difference between the control information by the PID control of the control information generating unit 22 and the control information by the feedforward control of the feedforward control unit 16, and outputs information indicating this difference as control information u to the pulse generating unit 24. The pulse generating unit 24 generates a pair of pulse signals based on the control information u, and outputs each of the generated pulse signals to the third adding / subtracting unit 25.

[0058] The third addition / subtraction unit 25 adds the disturbance information converted into pulse information by the disturbance information conversion unit 15 to each pulse signal generated by the pulse generation unit 24, and outputs the result as electrical stimulation signals S1 and S2. In other words, the third addition / subtraction unit 25 generates electrical stimulation signals based on the disturbance information. The electrical stimulation signal S1 is a signal that controls electrical stimulation to the extensor muscles. The electrical stimulation signal S2 is a signal that controls electrical stimulation to the flexor muscles. The electrical stimulation signals S1 and S2 are output to the disturbance calculation unit 13 and the electrical stimulation unit 2, respectively. The electrical stimulation signal S1 corresponds to the first electrical stimulation signal, and the electrical stimulation signal S2 corresponds to the second electrical stimulation signal.

[0059] The electrical stimulation unit 2 applies electrical stimulation to the muscle α based on the generated electrical stimulation signals S1 and S2. The electrical stimulation unit 2 applies electrical stimulation to the extensor muscles in response to the electrical stimulation signal S1. The electrical stimulation unit 2 applies electrical stimulation to the flexor muscles in response to the electrical stimulation signal S2. The extensor muscles and flexor muscles contract in response to the electrical stimulation applied from the electrical stimulation unit 2. As a result, the joints move in conjunction with the movements of the extensor muscles and flexor muscles. The angle at which the joints move is determined by the angle response value θ res The detection unit 3 detects the detected angle response value θ res is output as actual information to the first addition / subtraction unit 21 and the disturbance calculation unit 13. In other words, the detection unit 3 obtains and outputs actual information regarding the actual movement of the muscle α.

[0060] The disturbance calculation unit 13 obtains estimation information indicating an estimation result of the motion of the muscle α when the electrical stimulation based on the electrical stimulation signals S1 and S2 is applied by the muscle model. The disturbance calculation unit 13 estimates the motion of the muscle α when the electrical stimulation based on the electrical stimulation signals S1 and S2 is applied to the muscle α based on the electrical stimulation signals S1 and S2 in the estimation unit 31, based on the electrical stimulation signals S1 and S2 and the muscle model. At this time, the muscle model may include a plurality of muscle models corresponding to the extensor muscle and the flexor muscle. In this case, the electrical stimulation signal S1 is input to the muscle model corresponding to the extensor muscle. The electrical stimulation signal S2 is input to the muscle model corresponding to the flexor muscle. The muscle model outputs the estimation information by inputting the information related to the electrical stimulation signals S1 and S2. The estimation information includes torque information indicating the torque generated in the muscle α when the electrical stimulation based on the electrical stimulation signals S1 and S2 is applied to the muscle α. The estimation unit 31 outputs the estimation information to the fourth addition and subtraction unit 33.

[0061] The disturbance calculation unit 13 converts the angle response value θ detected by the detection unit 3 into the detected information in the detection information conversion unit 32. res The detected information conversion unit 32 converts angle information indicating the angle at which the joint moves into torque information. In other words, the detected information conversion unit 32 outputs torque information indicating the torque actually generated in the muscle α by multiplying the input of actual information regarding the angle at which the joint moves by a predetermined transfer function. The detected information conversion unit 32 outputs the actual information converted from angle information into torque information to the fourth addition / subtraction unit 33.

[0062] The disturbance calculation unit 13 calculates disturbance information indicating the influence of the disturbance on the actual information based on the estimated information output from the estimation unit 31 and the actual information converted by the detection information conversion unit 32. The disturbance calculation unit 13 calculates the difference between the estimated information output from the estimation unit 31 and the actual information converted by the detection information conversion unit 32 in the fourth addition / subtraction unit 33, and outputs information indicating the difference as disturbance information to the filter unit 34. The disturbance information output from the fourth addition / subtraction unit 33 is torque information of the disturbance. The filter unit 34 filters the disturbance information output from the fourth addition / subtraction unit 33. As a result, noise is removed from the disturbance information output from the fourth addition / subtraction unit 33. The disturbance information output from the filter unit 34 is input to the disturbance information conversion unit 15. The disturbance information conversion unit 15 converts the disturbance information output from the disturbance calculation unit 13 from torque information to pulse information. As described above, in the control shown in FIG. 2, only position control is performed.

[0063] Next, a hardware configuration of the main body 4 in the electrical stimulation device 1 will be described with reference to Fig. 3. Fig. 3 is a diagram showing an example of a hardware configuration of the main body 4.

[0064] The main body 4 includes a processor 101, a main memory 102, an auxiliary memory 103, a communication device 104, an input device 105, and an output device 106. The main body 4 includes one or more computers configured with these hardware devices and software such as programs. Each of the goal determination unit 11, the stimulus signal generation unit 12, the disturbance calculation unit 13, the model storage unit 14, the disturbance information conversion unit 15, and the feedforward control unit 16 may be configured with one computer or multiple computers. The main body 4 is realized by the cooperation of hardware and software.

[0065] When the main body 4 is composed of multiple computers, these computers may be connected locally or via a communication network such as the Internet or an intranet. This connection logically constitutes a single main body 4.

[0066] The processor 101 executes an operating system, application programs, etc. The main memory 102 is composed of a read only memory (ROM) and a random access memory (RAM). For example, at least some of the various functional units of the main body 4 may be realized by the processor 101 and the main memory 102.

[0067] The auxiliary storage device 103 is a storage medium including a hard disk, a flash memory, etc. The auxiliary storage device 103 generally stores a larger amount of data than the main storage device 102. For example, at least a part of the model storage unit 14 may be realized by the auxiliary storage device 103.

[0068] The communication device 104 is configured with a network card or a wireless communication module. For example, at least a part of the goal determination unit 11 can be realized by the communication device 104. The input device 105 is configured with a keyboard, a mouse, a touch panel, etc. For example, at least a part of the goal determination unit 11 can be realized by the input device 105. The output device 106 is configured with a printer, etc.

[0069] The auxiliary storage device 103 stores in advance a program and data necessary for processing. This program causes the computer to execute each functional element of the main body unit 4. This program causes, for example, each process in a state identification method described below to be executed in the computer. This program may be provided in a state recorded on a tangible recording medium such as a CD-ROM, a DVD-ROM, or a semiconductor memory. This program may be provided as a data signal via a communication network.

[0070] Next, an electrical stimulation device 1A in a modified example of this embodiment will be described with reference to FIG. 4 and FIG. 5. FIG. 4 is a block diagram of an electrical stimulation device in a modified example of this embodiment. The electrical stimulation device 1A is generally similar or the same as the electrical stimulation device 1 in the above-mentioned embodiment and modified example. The electrical stimulation device 1A differs from the above-mentioned electrical stimulation device 1 in that the detection unit 3 detects myoelectricity instead of the movement angle of the joint, the feedforward control unit 16 is not included, and the second addition / subtraction unit 23 is not included, the target determination unit 11 outputs a torque command value instead of an angle command value, the detection information conversion unit 32 is not included, the third addition / subtraction unit 25 is not included, and disturbance information is input to the fifth addition / subtraction unit 26. Hereinafter, the differences between the above-mentioned embodiment and the modified example will be mainly described.

[0071] As shown in FIG. 4, in this modification, the disturbance information conversion unit 15 converts the disturbance information output from the disturbance calculation unit 13 from torque information to control information corresponding to the control information output from the control information generation unit 22. In this modification, the stimulation signal generation unit 12 includes a fifth addition / subtraction unit 26. The fifth addition / subtraction unit 26 adds the control information output from the control information generation unit 22 and the control information output from the disturbance information conversion unit 15. The fifth addition / subtraction unit 26 outputs, for example, information obtained by adding the control information output from the control information generation unit 22 and the control information output from the disturbance information conversion unit 15 to the pulse generation unit 24 as new control information. In this modification, the pulse generation unit 24 generates a pulse signal based on the control information output from the fifth addition / subtraction unit 26. The pulse generation unit 24 outputs the generated pulse signal to the electrical stimulation unit 2 and the estimation unit 31 as an electrical stimulation signal. In this modification, when the detection unit 3 outputs torque information as actual information, the detection unit 3 outputs the actual information to the fourth addition / subtraction unit 33 without going through the detection information conversion unit 32 .

[0072] Next, an example of an electrical stimulation method using the electrical stimulation device 1A shown in Fig. 4 will be described with reference to Fig. 4 and Fig. 5. Fig. 5 is a schematic diagram of control performed in the electrical stimulation device 1A.

[0073] In the control shown in FIG. 5, the target determination unit 11 determines the torque command value T cmd In this modification, the target determination unit 11 outputs a torque command value T cmd and the torque command value T corresponding to the flexor of muscle α cmd The torque command value T cmd are input to the first addition / subtraction unit 21. The first addition / subtraction unit 21 receives the torque response value T res and the torque command value T cmd The first addition / subtraction unit 21 calculates the difference between the torque response value T res and the torque command value T cmd and a difference between the difference and the input difference information. Difference information indicating each difference calculated in the first addition / subtraction unit 21 is input to the control information generation unit 22. That is, the first addition / subtraction unit 21 calculates a control deviation of the feedback control and inputs it to the control information generation unit 22. The control information generation unit 22 executes PID control based on each input difference information, and outputs a pair of control information to the fifth addition / subtraction unit 26. The pair of control information includes control information corresponding to the extensor muscles and control information corresponding to the flexor muscles.

[0074] The fifth addition / subtraction unit 26 adds the control information converted by the disturbance information conversion unit 15 to each of the pair of control information by the PID control of the control information generation unit 22. The fifth addition / subtraction unit 26 adds the control information corresponding to the extensor muscle output from the disturbance information conversion unit 15 to the control information corresponding to the extensor muscle output from the control information generation unit 22, and outputs the control information u corresponding to the extensor muscle to the pulse generation unit 24. The fifth addition / subtraction unit 26 adds the control information corresponding to the flexor muscle output from the disturbance information conversion unit 15 to the control information corresponding to the flexor muscle output from the control information generation unit 22, and outputs the control information u corresponding to the flexor muscle to the pulse generation unit 24. The pulse generation unit 24 generates a pulse signal based on the control information u corresponding to the extensor muscle and outputs this pulse signal as the electrical stimulation signal S1. The pulse generation unit 24 generates a pulse signal based on the control information u corresponding to the flexor muscle and outputs this pulse signal as the electrical stimulation signal S2.

[0075] The electrical stimulation unit 2 applies electrical stimulation to the extensor muscles in response to the electrical stimulation signal S1. The electrical stimulation unit 2 applies electrical stimulation to the flexor muscles in response to the electrical stimulation signal S2. The extensor muscles and flexor muscles contract in response to the electrical stimulation applied from the electrical stimulation unit 2. As a result, the joints move in conjunction with the movements of the extensor muscles and flexor muscles. The detection unit 3 detects the myoelectricity of the extensor muscles and outputs the detection result as actual information to the first addition / subtraction unit 21 and the fourth addition / subtraction unit 33 of the disturbance calculation unit 13. The detection unit 3 detects the myoelectricity of the flexor muscles and outputs the detection result as actual information to the first addition / subtraction unit 21 and the fourth addition / subtraction unit 33 of the disturbance calculation unit 13. The detection result of the myoelectricity corresponds to the torque generated in each muscle α.

[0076] The disturbance calculation unit 13, in the estimation unit 31, estimates the movement of the muscle α when the electrical stimulation based on the electrical stimulation signals S1, S2 is applied to the muscle α based on each of the electrical stimulation signals S1, S2 and the muscle model. The muscle model outputs estimated information corresponding to the extensor muscle and estimated information corresponding to the flexor muscle by inputting information related to the electrical stimulation signals S1, S2. The estimated information corresponding to the extensor muscle includes torque information indicating the torque generated in the extensor muscle when the electrical stimulation based on the electrical stimulation signal S1 is applied to the extensor muscle. The estimated information corresponding to the flexor muscle includes torque information indicating the torque generated in the flexor muscle when the electrical stimulation based on the electrical stimulation signal S2 is applied to the flexor muscle. The estimation unit 31 outputs each piece of estimated information to the fourth addition / subtraction unit 33.

[0077] The disturbance calculation unit 13 calculates the difference between the estimated information corresponding to the extensor muscle and the information related to the actual information corresponding to the extensor muscle in the fourth addition / subtraction unit 33, and outputs the information indicating the difference to the filter unit 34 as disturbance information. The disturbance calculation unit 13 calculates the difference between the estimated information corresponding to the flexor muscle and the information related to the actual information corresponding to the flexor muscle in the fourth addition / subtraction unit 33, and outputs the information indicating the difference to the filter unit 34 as disturbance information. Each disturbance information output from the fourth addition / subtraction unit 33 is disturbance torque information. The filter unit 34 filters the disturbance information output from the fourth addition / subtraction unit 33. The disturbance information output from the filter unit 34 is input to the disturbance information conversion unit 15. The disturbance information conversion unit 15 converts the disturbance information output from the disturbance calculation unit 13 from torque information to control information. As described above, according to the control shown in FIG. 4, only force control is performed.

[0078] As a modification of this embodiment, the force control may be performed by impedance control or compliance control. In this case, the main body 4 may set the impedance in the impedance control or the compliance in the compliance control based on the disturbance information output from the disturbance calculation unit 13. In this case, the stimulation signal generation unit 12 generates an electrical stimulation signal based on, for example, the set impedance or compliance.

[0079] Next, an electrical stimulation device 1B in a modified example of this embodiment will be described with reference to Figs. 6 and 7. Fig. 6 is a block diagram of an electrical stimulation device in another modified example of this embodiment. The electrical stimulation device 1B is generally similar or the same as the above-mentioned embodiment and modified example. The electrical stimulation device 1B differs from the electrical stimulation device 1 in that it does not include a disturbance information conversion unit 15, does not include a feedforward control unit 16, the target determination unit 11 outputs an angle command value and a torque command value, does not include a second addition / subtraction unit 23 and a third addition / subtraction unit 25, and disturbance information is input to a sixth addition / subtraction unit 27. Hereinafter, the differences between the above-mentioned embodiment and the modified example will be mainly described.

[0080] As shown in FIG. 6, in this modification, the target determination unit 11 outputs an angle command value, a torque command value, and command information. The target determination unit 11 outputs the angle command value to the first addition / subtraction unit 21, and outputs the torque command value to the sixth addition / subtraction unit 27. In this modification, the stimulation signal generation unit 12 includes a sixth addition / subtraction unit 27. The sixth addition / subtraction unit 27 adds the command information output from the target determination unit 11 and the disturbance information output from the disturbance calculation unit 13, and outputs information in which the disturbance information is added to the command information of the torque command value to the control information generation unit 22. The control information generation unit 22 outputs the generated control information to the pulse generation unit 24. In this modification, the pulse generation unit 24 outputs the generated pulse signal to the electrical stimulation unit 2 and the estimation unit 31 as an electrical stimulation signal. In this modification, the disturbance calculation unit 13 outputs the disturbance information to the sixth addition / subtraction unit 27 without going through the disturbance information conversion unit 15.

[0081] An example of an electrical stimulation method using the electrical stimulation device 1B shown in Fig. 6 will be described with reference to Fig. 6 and Fig. 7. Fig. 7 is a schematic diagram of control performed in an electrical stimulation device according to another modified example of the present embodiment.

[0082] In the control shown in FIG. 7, the target determination unit 11 determines the angle command value θ cmd and torque command value T cmd In other words, the command information output from the target determination unit 11 includes position information related to the motion of the muscle α and force information related to the motion of the muscle α. cmd and torque command value T cmd are input to the first addition / subtraction unit 21. The first addition / subtraction unit 21 receives the angle response value θ res and the angle command value θ cmd and outputs difference information indicating the calculated difference to the control information generating unit 22. That is, the first adding / subtracting unit 21 calculates a control deviation of the feedback control and inputs it to the control information generating unit 22. The control information generating unit 22 executes PID control based on the input difference information.

[0083] The sixth addition / subtraction unit 27 calculates the torque command value T cmd The disturbance information output from the disturbance calculation unit 13 is added to the torque command value T cmd is corrected based on the disturbance information. In other words, the force information related to the motion of the muscle α among the command information is corrected based on the disturbance information. cmd No feedforward control is performed on the information.

[0084] The control information generator 22 calculates the angle response value θ res and the angle command value θ cmd The difference information and the torque command value T cmd In other words, the control information generating unit 22 generates the control information u based on the position information and the force information corrected by the disturbance information. The control information generating unit 22 outputs the control information u to the pulse generating unit 24. The pulse generating unit 24 generates a pair of pulse signals based on the control information u. The pulse generating unit 24 outputs the pair of pulse signals as the electrical stimulation signals S1, S2. In other words, the pulse generating unit 24 generates the electrical stimulation signals based on the control information u. In further other words, the pulse generating unit 24 generates the electrical stimulation signals based on the force information and the position information corrected by the disturbance information.

[0085] The electrical stimulation unit 2 applies electrical stimulation to the extensor muscles in response to the electrical stimulation signal S1. The electrical stimulation unit 2 applies electrical stimulation to the flexor muscles in response to the electrical stimulation signal S2. The extensor muscles and flexor muscles contract in response to the electrical stimulation applied from the electrical stimulation unit 2. As a result, the joints move in conjunction with the movements of the extensor muscles and flexor muscles. The angle at which the joints move is determined by the angle response value θ res The detection unit 3 detects the detected angle response value θ res The first adding / subtracting unit 21 outputs the actual information detected by the detecting unit 3 and the angle command value θ cmd The difference between these is calculated.

[0086] The disturbance calculation unit 13, in the estimation unit 31, estimates the movement of the muscle α when the electrical stimulation based on the electrical stimulation signals S1, S2 is applied to the muscle α based on the electrical stimulation signals S1, S2, based on the electrical stimulation signals S1, S2 and the muscle model. The muscle model outputs estimation information by inputting information related to the electrical stimulation signals S1, S2. The estimation information includes torque information indicating the torque generated in the muscle α when the electrical stimulation based on the electrical stimulation signals S1, S2 is applied to the muscle α. The estimation unit 31 outputs the estimation information to the fourth addition / subtraction unit 33.

[0087] The disturbance calculation unit 13 converts the angle response value θ detected by the detection unit 3 into the detected information in the detection information conversion unit 32. res The detected information conversion unit 32 converts the angle information into torque information. The detected information conversion unit 32 outputs actual information obtained by converting the angle information into torque information to the fourth addition and subtraction unit 33.

[0088] The disturbance calculation unit 13 calculates the difference between the estimated information output from the estimation unit 31 and the actual information converted by the detection information conversion unit 32 in the fourth addition / subtraction unit 33, and outputs information indicating this difference as disturbance information to the filter unit 34. The disturbance information output from the fourth addition / subtraction unit 33 is disturbance torque information. The filter unit 34 filters the disturbance information output from the fourth addition / subtraction unit 33. The disturbance information output from the filter unit 34 is output to the first addition / subtraction unit 21. The disturbance information output to the first addition / subtraction unit 21 is used as a torque command value T cmd As described above, according to the control shown in FIG. 7, both the position control and the force control are performed. The disturbance information is added to the torque command value T cmd is added to.

[0089] Next, the effects of the electrical stimulation devices 1, 1A, and 1B according to the above-described embodiments will be described.

[0090] In the electrical stimulation device 1, 1A, 1B, the disturbance calculation unit 13 calculates disturbance information indicating the effect of a disturbance on the actual information based on actual information on the actual muscle movement and estimated information indicating the estimated result of the muscle movement. The stimulation signal generation unit 12 generates an electrical stimulation signal based on the disturbance information calculated by the disturbance calculation unit 13. In this way, in the electrical stimulation device 1, 1A, 1B, disturbance information on the force applied to the muscle from the outside is calculated, and an electrical stimulation signal is generated based on the calculated disturbance information. In other words, a disturbance observer is applied in the control of the muscle of a living body. This configuration can be applied to both position control and force control, and to both position control and force control. As a result, the disturbance suppression characteristic against the force applied to the muscle from the outside is improved. In other words, even in a situation where a force is applied to the muscle from the outside, robustness can be ensured. Therefore, the muscle movement can be controlled in a state where robustness is ensured. Furthermore, according to this electrical stimulation device 1, 1A, 1B, acceleration control can be realized. If acceleration control can be realized, force control and a combination of position control and force control are possible, which allows the living body to perform more delicate movements by electrical stimulation.

[0091] In the electrical stimulation devices 1, 1A, and 1B, the disturbance calculation unit 13 calculates estimated information based on a muscle model and the electrical stimulation signal generated by the stimulation signal generation unit 12. The muscle model is a model that outputs estimated information in response to input of information related to the electrical stimulation signal. The disturbance calculation unit 13 calculates, as disturbance information, information indicating the difference between the calculated estimated information and information related to the actual information detected by the detection unit. In this case, the disturbance information can be calculated more accurately.

[0092] In the electrical stimulation device 1, 1A, 1B, the stimulation signal generating unit 12 acquires command information, actual information, and disturbance information. The command information indicates a target value related to muscle movement. The stimulation signal generating unit 12 generates an electrical stimulation signal based on the command information, actual information, and disturbance information. In this case, since the stimulation signal generating unit 12 generates an electrical stimulation signal based on both the command information and the actual information, it is possible to more reliably achieve both the tracking characteristic and the disturbance suppression characteristic. For example, the stimulation signal generating unit 12 can perform feedback control based on the command information and actual information. In this case, it is possible to improve the tracking characteristic while ensuring the disturbance suppression characteristic.

[0093] In the electrical stimulation device 1, 1A, the stimulation signal generating unit 12 includes a first addition / subtraction unit 21 and a control information generating unit 22. The first addition / subtraction unit 21 acquires difference information indicating the difference between the command information and the actual information. The control information generating unit 22 generates control information for generating an electrical stimulation signal based on the difference information. The stimulation signal generating unit 12 generates an electrical stimulation signal based on the control information and the disturbance information. In this case, the tracking characteristic can be ensured by generating the control information. For example, the control information generating unit 22 can determine the parameters of the PID control by considering only the tracking characteristic. Since the electrical stimulation signal is generated based on the control information and the disturbance information after the control information is generated, it is possible to more easily and reliably achieve both the securing of the tracking characteristic and the securing of the disturbance suppression characteristic.

[0094] In the electrical stimulation devices 1, 1A, and 1B, the electrical stimulation signals include an electrical stimulation signal S1 that controls electrical stimulation to the extensor muscles, and an electrical stimulation signal S2 that controls electrical stimulation to the flexor muscles. The relationship between the muscle contraction of the extensor muscles and the flexor muscles is closely related to the movement of a joint. By controlling the movement of the extensor muscles and the movement of the flexor muscles by the electrical stimulation signals, the movement of a living body can be controlled more accurately and naturally.

[0095] In the electrical stimulation device 1, 1A, 1B, the pulse generating unit 24 generates a first and a second pulse signal. The first pulse signal corresponds to the electrical stimulation signal S1. The second pulse signal corresponds to the electrical stimulation signal S2. The pulse generating unit 24 acquires total information corresponding to the sum of the first pulse signal and the second pulse signal, and difference information corresponding to the difference between the first pulse signal and the second pulse signal. The pulse generating unit 24 generates the first pulse signal and the second pulse signal based on the acquired total information and difference information. In this case, the movements of the extensor and flexor muscles can be more highly controlled. For example, the movements of the extensor muscles and the flexor muscles can be balanced according to the command information. The electrical stimulation signal is a pulse signal. The stimulation signal generating unit 12 modifies the pulse width of the electrical stimulation signal according to the disturbance information. In this case, the muscle movements can be more reliably controlled by the electrical stimulation signal.

[0096] In the electrical stimulation device 1, the disturbance information converter 15 converts the disturbance information into pulse information corresponding to the pulses of the electrical stimulation signal. The stimulation signal generator 12 sets the pulse width of the electrical stimulation signal based on the disturbance information converted by the disturbance information converter 15. In this case, the electrical stimulation signal is directly corrected based on the disturbance information, so that the disturbance suppression characteristic can be further improved.

[0097] In the electrical stimulation device 1, the feedforward control unit 16 performs feedforward control based on command information. The stimulation signal generating unit 12 generates an electrical stimulation signal based on information output from the feedforward control unit. In this case, the feedforward control unit 16 can also perform control taking disturbance into consideration. If a certain degree of disturbance suppression characteristics is ensured by the feedforward control unit 16, the accuracy of muscle movement in response to command information can be further improved by generating an electrical stimulation signal based on disturbance information calculated by the disturbance calculation unit. It is possible to reduce the influence of disturbance in position control based on output information from the feedforward control unit 16, and to reduce the influence of disturbance in force control based on disturbance information calculated by the disturbance calculation unit 13.

[0098] In the electrical stimulation device 1B, the command information includes position information related to the muscle movement and force information related to the muscle movement. The stimulation signal generating unit 12 corrects the force information based on the disturbance information. The stimulation signal generating unit 12 generates an electrical stimulation signal based on the displacement information and the corrected force information. In this case, the disturbance suppression characteristic can be improved with respect to the force generated in the muscle while the tracking characteristic is ensured based on the position information. Therefore, the movement in which the living body receives a reaction force from an external object, such as gripping an object, can be more accurately performed.

[0099] In the electrical stimulation device 1A, the stimulation signal generating unit 12 sets the impedance in the impedance control or the compliance in the compliance control based on the disturbance information. The stimulation signal generating unit 12 generates an electrical stimulation signal based on the set impedance or compliance. In this case, in controlling the movement of the muscle by electrical stimulation, impedance control or compliance control can be performed more appropriately taking into account the force applied to the muscle from the outside.

[0100] Next, an example of the verification of the electrical stimulation device 1 will be described with reference to FIG. 8 to FIG. 12. In this verification, as shown in FIG. 8, the detection unit 3 includes a rotating table 61, a fixed bar 62 fixed to the rotating table 61, and a motor 63. The motor 63 detects the rotation angle and rotation torque of the rotating table 61. The motor 63 generates torque according to the inputted and specified information for the verification. The forearm 51 and hand 52 of the living body 50 were restrained by the fixed bar 62 and the fixture 64 so that the wrist 53 was located on the central axis of the rotating table 61. The fixed bar 62 was pushed by the hand 52, and the rotating table 61 was rotated by the angle of the wrist joint. The pads of the electrical stimulation unit 2 were attached to the extensor muscle group side and the flexor muscle group side of the forearm 51 of the living body 50, respectively. With the above configuration, only the angle of the wrist joint during palmar flexion and dorsiflexion was measured.

[0101] In this verification, the living body 50 is a healthy person. In order to avoid muscle contraction by a command from the brain, the living body 50 was in a relaxed state. Therefore, in a state in which no electrical stimulation is applied to the muscle, as shown in FIG. 8, the hand 52 extends straight relative to the forearm 51. This state is defined as an angle of 0 rad. The stimulation intensity applied to the muscle was changed by modulating the pulse width of the electrical stimulation signal. The above-mentioned "K / (1+Ts)" was used as the transfer function of the muscle model. In this verification, the electrical stimulation device 1 has a configuration in which the feedforward control unit 16 is removed from the configuration shown in FIG. 2. These conditions are common to the identification experiment, the verification experiment of the disturbance suppression characteristic, and the verification experiment of the tracking characteristic, which will be described later.

[0102] The gain "K" and the time constant "T" were determined based on the results of the identification experiment. In the identification experiment, an arbitrary pulse signal was input as an electrical stimulation signal to each of the electrical stimulation unit 2 on the extensor side and the electrical stimulation unit 2 on the flexor side, and the relationship between the pulse signal and the rotational torque detected by the motor 63 was measured. As a result, in the identification experiment in this verification, it was revealed that the value of the gain "K" tends to decrease as the pulse width increases. For this reason, the gain "K" of the muscle model was changed according to the input pulse based on the approximation curve of the plot of the pulse width and the gain "K" obtained by the experimental results of the identification experiment. It was considered from the experimental results of the identification experiment that the time constant "T" depends on the rise time and does not depend on the pulse width. For this reason, the average value of the time constant "T" was calculated and the value was adopted. The time constant "T" on the flexor side was set to 0.2060 seconds, and the time constant "T" on the extensor side was set to 0.3052 seconds.

[0103] Next, the results of a verification experiment on the disturbance suppression characteristics of the electrical stimulation device 1 will be described. cmd An electrical stimulation signal was generated based on the command information with φ = 0 rad, and the generated electrical stimulation signal was output to the electrical stimulation unit 2. The motor 63 was controlled to generate a torque shown in Fig. 9 as a disturbance. In other words, the motor 63 generated a torque that drew a sine curve over time as a disturbance.

[0104] As a result of the experiment, the rotation angle detected by the motor 63 was measured as shown in Fig. 10(a) and Fig. 10(b). That is, the measurement result is an angle response value when electrical stimulation is given to the living body 50. In Fig. 10(a) and Fig. 10(b), the solid line indicates command information, and the dashed line indicates the measurement result. Fig. 10(a) shows the measurement result of the comparative example. Fig. 10(b) shows the measurement result of the above-mentioned electrical stimulation device 1. The comparative example does not include the disturbance calculation unit 13, the disturbance information conversion unit 15, and the feedforward control unit 16. That is, in the comparative example shown in Fig. 10(a), the electrical stimulation signal was generated only by feedback control using PID control.

[0105] As shown in Fig. 10(a), in the comparative example, the measurement result was close to a sine curve due to the influence of disturbance. As shown in Fig. 10(b), in the electrical stimulation device 1 without the feedforward control unit 16, the influence of disturbance was reduced and the measurement result shifted near 0 degrees.

[0106] The number of data is “n”, and the command information is “θ cmd " and the measured rotation angle is "θ res ", the root mean square error (RMSE) is defined as the following equation (1).

number

[0107] In this case, the RMSE was 0.0997 rad in the comparative example. The RMSE was 0.0132 rad in the electrical stimulation device 1. Thus, it was confirmed that the disturbance suppression characteristic of the electrical stimulation device 1 was improved compared to the comparative example, even in a state where the feedforward control unit 16 was removed.

[0108] Next, a description will be given of the results of an experiment verifying the tracking characteristics of the electrical stimulation device 1. In this experiment, an electrical stimulation signal was generated based on command information in which the value of the angle command value forms a sine curve over time as shown in Fig. 11, and the generated electrical stimulation signal was output to the electrical stimulation unit 2.

[0109] As a result of the experiment, the rotation angle detected by the motor 63 was measured as shown in Fig. 12(a) and Fig. 12(b). That is, the measurement result is an angle response value when electrical stimulation is given to the living body 50. In Fig. 12(a) and Fig. 12(b), the solid line indicates command information, and the dashed line indicates the measurement result. Fig. 12(a) shows the measurement result of the comparative example. Fig. 12(b) shows the measurement result of the electrical stimulation device 1 from which the feedforward control unit 16 has been removed. As with the above comparative example, the comparative example does not include the disturbance calculation unit 13, the disturbance information conversion unit 15, and the feedforward control unit 16. That is, in the comparative example shown in Fig. 12(a), the electrical stimulation signal was generated only by feedback control using PID control.

[0110] As shown in Fig. 12(a), in the comparative example, the measurement results deviated significantly from the command information. As shown in Fig. 12(b), in the electrical stimulation device 1, the measurement results track the command information. In the electrical stimulation device 1, the measurement results track the command information even when changing direction. It was confirmed that the tracking characteristics of the measurement results of the electrical stimulation device 1 were higher than the tracking characteristics of the measurement results of the comparative example.

[0111] In this case, the RMSE was 0.03896 rad in the comparative example. The RMSE was 0.02116 rad in the electrical stimulation device 1. Thus, it was quantitatively confirmed that the tracking characteristics of the electrical stimulation device 1 were improved compared to the comparative example even in a state in which the feedforward control unit 16 was removed. Note that an even smaller RMSE was confirmed in the electrical stimulation device 1 including the feedforward control unit 16.

[0112] The above describes the embodiments and modifications of the present invention, but the present invention is not necessarily limited to the above-described embodiments and modifications, and various modifications are possible without departing from the spirit of the present invention.

[0113] For example, the configurations and controls shown in Figures 1, 2, and 4 to 7 may be combined with each other. For example, the configurations shown in Figures 4 and 6 may include a feedforward control unit 16. In this case, feedforward control may be incorporated in the controls shown in Figures 5 and 7.

[0114] In the above-described embodiment and modified examples, an actual information conversion unit that converts actual information detected by the detection unit 3 may be further provided. This actual information conversion unit converts the actual information detected by the detection unit 3 into a predetermined information format, for example, and outputs it to the first addition / subtraction unit 21. For example, in the configuration and control shown in Figs. 4 and 5, this actual information conversion unit may convert the actual information detected by the detection unit 3 from torque information to angle information. In this case, in the configuration and control shown in Figs. 4 and 5, the target determination unit 11 converts the angle command value θ cmd may be output to the first addition / subtraction unit 21.

[0115] In the configuration and control shown in Figures 4 and 5, in which the detection unit 3 outputs torque information to the first addition and subtraction unit 21 and the disturbance calculation unit 13, the detection unit 3 may be provided on an object with which the living body interferes, and detect the force applied to this object. [Explanation of symbols]

[0116] 1...electrical stimulation device, 3...detection unit, 12...stimulation signal generation unit, 13...disturbance calculation unit, 16...feedforward control unit, 21...first addition / subtraction unit, 22...control information generation unit, S1, S2...electrical stimulation signal, u...control information, α...muscle.

Claims

1. A signal generating unit that generates an electrical stimulation signal for controlling electrical stimulation to a muscle; A detection unit for detecting actual information regarding the actual movement of the muscle; a disturbance calculation unit that calculates disturbance information indicating an effect of a disturbance on the actual information based on estimated information indicating an estimated result of a movement of the muscle when an electrical stimulus based on the electrical stimulus signal is applied to the muscle, The signal generating unit generates the electrical stimulation signal based on disturbance information calculated by the disturbance calculating unit.

2. the disturbance calculation unit calculates the estimated information based on a muscle model that outputs the estimated information in response to input of information about the electrical stimulation signal and the electrical stimulation signal generated by the signal generation unit; The electrical stimulation device according to claim 1 , wherein information indicating a difference between the calculated estimated information and information relating to actual information detected by the detection unit is calculated as the disturbance information.

3. 3. The electrical stimulation device according to claim 1, wherein the signal generating unit acquires command information indicating a target value for the movement of the muscle, the actual information, and the disturbance information, and generates the electrical stimulation signal based on the command information, the actual information, and the disturbance information.

4. The electrical stimulation device of claim 3, wherein the signal generating unit includes a difference acquiring unit that acquires difference information indicating a difference between the command information and the actual information, and a control information generating unit that generates control information for generating the electrical stimulation signal based on the difference information, and generates the electrical stimulation signal based on the control information and the disturbance information.

5. The muscles include extensor and flexor muscles, 5. The electrical stimulation device according to claim 1, wherein the electrical stimulation signal includes a first electrical stimulation signal that controls electrical stimulation to the extensor muscles and a second electrical stimulation signal that controls electrical stimulation to the flexor muscles.

6. the signal generating unit includes a pulse generating unit that generates first and second pulse signals; the first pulse signal corresponds to the first electrical stimulation signal; the second pulse signal corresponds to the second electrical stimulation signal; 6. The electrical stimulation device according to claim 5, wherein the pulse generating unit acquires total information corresponding to a sum of the first pulse signal and the second pulse signal and difference information corresponding to a difference between the first pulse signal and the second pulse signal, and generates the first pulse signal and the second pulse signal based on the acquired total information and difference information.

7. the electrical stimulation signal is a pulse signal, The electrical stimulation device according to claim 1 , wherein the signal generating section sets a pulse width of the electrical stimulation signal in response to the disturbance information.

8. a converter that converts the disturbance information into pulse information corresponding to a pulse of the electrical stimulation signal; The electrical stimulation device according to claim 7 , wherein the signal generating section sets a pulse width of the electrical stimulation signal based on the disturbance information converted by the converting section.

9. a feedforward control unit that performs feedforward control based on command information indicating a target value related to the muscle movement, The electrical stimulation device according to claim 1 , wherein the signal generating section generates the electrical stimulation signal based on information output from the feedforward control section.

10. the command information indicating a target value related to the muscle motion includes position information related to the muscle motion and force information related to the muscle motion; The electrical stimulation device according to claim 1 , wherein the signal generating unit modifies the force information based on the disturbance information, and generates the electrical stimulation signal based on the position information and the modified force information.

11. The electrical stimulation device according to claim 1 , wherein the signal generating unit sets an impedance in impedance control or a compliance in compliance control based on the disturbance information, and generates the electrical stimulation signal based on the set impedance or compliance.

12. Obtaining actual information about actual muscle movements; obtaining estimated information indicating an estimated result of a motion of the muscle when an electrical stimulus based on an electrical stimulus signal is applied to the muscle; calculating disturbance information indicating an effect of a disturbance on the actual information based on the actual information and the estimated information; generating the electrical stimulation signal based on the disturbance information.

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