CN111449813B - Wearable electrical stimulation system for artificial hand motion posture sensory feedback - Google Patents

Abstract

The invention relates to a wearable electrical stimulation system for prosthetic hand motion posture sensory feedback, which belongs to the technical field of electrical stimulation systems for artificial limbs, and includes an armband body and an electrical stimulator; the armband body is provided with corresponding electrical stimulation points hole position; the electrical stimulator is set on the armband body, including: microcontroller, power supply circuit, H-bridge circuit, constant current source circuit, electrodes; the microcontroller reads the real-time motion posture information of the prosthetic hand fingers, and according to The motion posture information sends the corresponding electric stimulation control command to the H bridge circuit and the constant current source circuit; the power circuit provides the working voltage for the microcontroller, the H bridge circuit and the constant current source circuit; the electrode is a self-adhesive electrode sheet, and the negative electrode is placed on the forearm The extensor pollicis brevis, extensor little finger, extensor digitorum, flexor hallucis longus, and flexor digitorum superficiale are placed on the inner side of the arm ring and arranged around the arm. The invention is safe and reliable, works stably, and can feed back the movement attitude information of the prosthetic hand fingers to the user in the form of electrical stimulation in real time.

Description

A wearable electrical stimulation system for sensory feedback of prosthetic hand movements and postures

technical field

The invention belongs to the technical field of prosthetic electric stimulation systems, and relates to a wearable electric stimulation system for sensory feedback of prosthetic hand movement gestures.

Background technique

The upper limb disability has brought a lot of inconvenience to the patients, and the study, work and life have been greatly affected. Research on prosthetics can improve the quality of life of people with physical disabilities. The control of early intelligent prostheses mainly relied on the collection of myoelectric signals from the muscle surface of the user's residual limbs, which were processed and used to drive the prosthesis to complete specific actions. Since no feedback information is introduced, this open-loop control method is more laborious for the user, mainly relying on the person's own visual feedback to perceive the movement posture of the prosthetic hand. The wearer of the prosthetic hand needs to keep watching the movement of the prosthetic hand with a high degree of concentration. Moreover, there is a certain delay between the input of visual information and the output of control signals of the prosthetic hand.

Introducing sensory feedback into prosthetic control to form a closed control loop can greatly improve the controllability and flexibility of the prosthesis, enabling the prosthesis to better assist amputees to complete daily activities. Most of the prosthetic sensory feedback systems developed at this stage are tactile feedback to the fingers of the prosthetic hand, which is used to transmit grasping contact information to the human body. Collect the pressure information and sliding information of the fingertips, and act on the human body in the form of electrical stimulation or vibration stimulation, so that the user can feel the grip of the prosthetic hand, so as to control the prosthetic hand more precisely.

Chinese patent CN108733198A proposes an electrical stimulation system for generating artificial tactile sensation, fixing the stimulating electrode plate on the skin surface that needs to generate artificial tactile sensation, and receiving two-dimensional distribution information of tactile intensity and tactile type information from the host computer according to the microcontroller circuit , according to the tactile type information, adjust the current output intensity of the constant current output regulation circuit, and selectively activate each electrode site on the skin surface to output current or recycle current at different times, forming a circuit with the human subcutaneous tactile receptors, stimulating the corresponding neurons to generate Action potentials, thereby producing artificial tactile sensations.

In Lai Qiuxia's 2016 master's thesis of Huazhong University of Science and Technology, in the design and research of intelligent prosthetic grasping system based on vibration feedback, tactile sensors are installed on the fingertips of the prosthetic to obtain the pressure when grasping objects, and the micro The vibration strength of the vibration motor reflects the pressure on the prosthetic hand when grasping. The greater the pressure, the greater the vibration intensity of the motor, so as to assist the user to grasp better.

However, in addition to the information of the contact object, the information of the prosthetic hand also includes the state information of the movement, such as the grasping gesture of the hand and the bending movement of the fingers. Existing sensory feedback strategies for prosthetic hands lack the feedback on motion and posture information of prosthetic hands. If the motion posture information of the prosthetic hand is added to the closed-loop feedback of the prosthetic hand, the interaction between the user and the prosthetic hand will be further enhanced, thereby improving the user's proprioception of the prosthetic hand.

Finger movement perception mainly comes from the nerve input of muscle spindle receptors induced by muscle contraction of finger movement. The state of finger movement (movement speed, flexion and extension posture) will directly affect the output mode of muscle spindle receptors, but the sensory feedback of existing prosthetics does not make full use of prosthesis The state of finger movement affects the output of muscle spindle receptors. The technical idea of the present invention is to use the surface electrode to provide stimulating current to cause the contraction of the forearm muscle and its functional division muscle fiber corresponding to the finger, the muscle spindle receptor to form a sensory nerve impulse, and the target muscle position of the electrical stimulation signal is determined by the prosthetic finger (gesture action mode) participating in the movement. ) determines that the electrical stimulation signal output mode (start-end time, frequency, strength, etc.) of the electrical stimulation signal is controlled by the motion phase and posture of the corresponding prosthetic finger.

Contents of the invention

In view of this, the object of the present invention is to provide a wearable electrical stimulation system for the sensory feedback of the movement posture of the prosthetic hand, which is used to realize the sensory feedback of the movement posture of the fingers of the prosthetic hand and stimulate the user's arm in the form of electrical stimulation feedback Corresponding muscles produce real-time sensory feedback of finger movement.

To achieve the above object, the present invention provides the following technical solutions:

A wearable electrical stimulation system for sensory feedback of prosthetic hand movement posture, including armband body and electrical stimulator;

The armband body is used to be worn on the forearm, and holes corresponding to each electrical stimulation site are provided on it;

The electric stimulator is arranged on the body of the armband, including: a microcontroller, a power circuit, an H-bridge circuit, a constant current source circuit, and electrodes;

The microcontroller reads the real-time motion posture information of the fingers of the prosthetic hand, and sends corresponding electrical stimulation control commands to the H-bridge circuit and the constant current source circuit according to the motion posture information;

The power supply circuit is used to convert the input voltage into the working voltage corresponding to the microcontroller, the H bridge circuit and the constant current source circuit;

The H-bridge circuit is used to reverse the polarity of the stimulation waveform;

The constant current source circuit is used to ensure that the output current and the stimulating effect are not affected by changes in the impedance of the human body;

The electrode is a self-adhesive electrode sheet, its negative electrode is a stimulating electrode, and its positive electrode is a reference electrode. , the positive electrode is placed inside the armband and arranged along the circumference of the arm.

Further, the electrodes are placed in the corresponding positions to stimulate different forearm muscle groups and their multi-tendinous functional divisions, stimulate the current to induce corresponding muscle contraction, and form the corresponding finger flexion and extension movement sensation due to muscle fiber contraction and muscle spindle receptor excitement; Stimulating the extensor hallucis longus induces the motor sensation of stretching the thumb; stimulating the extensor of the index finger induces the motor sensation of extending the index finger; stimulating the extensor of the little finger induces the motor sensation of extending the little finger; The feeling of finger stretching; stimulating the flexor hallucis longus to induce the kinematic sensation of flexing the thumb; stimulating the index finger, middle finger, ring finger, and little finger of the superficial flexor to induce flexion of the index finger, middle finger, ring finger, and little finger respectively a feeling of.

The surface electrodes are used to provide stimulating current to cause the corresponding forearm muscle and its functional partition muscle fibers to contract, and the muscle spindle receptors form sensory nerve impulses. The target muscle position of the electrical stimulation signal is determined by the prosthetic finger (gesture action mode) participating in the movement. The electrical stimulation signal The output mode (start-end time, frequency, strength, etc.) of the electrical stimulation signal is controlled by the motion phase and posture of the corresponding prosthetic finger.

Further, the output waveform of the electrical stimulator is a biphasic square wave; the output frequency range is 10-100 Hz, and the precision is 1 Hz; the output amplitude range is 0-15 mA, and the precision is 0.1 mA; the output pulse width is fixed at 100-800 μs , the precision is 10μs; the number of electrical stimulation output channels is 8 channels, and the parameters of each channel can be adjusted independently.

Further, the microcontroller reads the real-time motion posture information of the fingers of the prosthetic hand according to the encoder of the internal motor of the finger of the prosthetic hand.

Further, the current motion posture information of the prosthetic finger includes the motion direction, motion speed, and current position of the prosthetic finger.

Further, the microcontroller selects the corresponding electrical stimulation mode according to the real-time motion posture information of the fingers of the prosthetic hand and sends corresponding control commands to realize the dynamic regulation of the electrical stimulation output.

Further, the electrical stimulation mode includes: selection of electrical stimulation frequency, selection of electrical stimulation intensity, selection of electrical stimulation channel.

Further, the dynamic regulation of the electrical stimulation output includes:

The position of the finger is defined according to the angle of the metacarpophalangeal joint of the finger, and the position of the finger is divided into three areas. The degree of muscle contraction is different at different positions. During muscle contraction, the proportion of high-frequency signals in the myoelectricity increases and the proportion of low-frequency signals decreases. Therefore, the frequency of the electrical stimulation output waveform is changed to reflect the position of the finger. The stronger the muscle contraction The higher the frequency of electrical stimulation; when the fingers do stretching exercises, the extensor muscles contract, then zone 1 corresponds to mode 1 with a low frequency, zone 2 corresponds to mode 2 with a medium frequency, zone 3 corresponds to mode 3 with a relatively high frequency; finger flexion When exercising, the flexor muscles contract, the frequency corresponding to Zone 1 is Mode 3, the frequency corresponding to Zone 2 is Mode 2, and the frequency corresponding to Zone 3 is Mode 1;

Divide the angular velocity of finger movement into four grades, when the angular velocity is zero, set it to grade 0, set the slower speed to grade 1, set the medium speed to grade 2, and set the faster speed to grade 3; finger movement The increase of the speed will lead to the increase of the neural activity of the motor cortex, so the angular velocity of the finger movement is reflected by changing the amplitude of the electrical stimulation output. The faster the angular velocity, the higher the amplitude of the electrical stimulation; The corresponding amplitude is lower amplitude, the corresponding amplitude of level 2 is medium amplitude, and the corresponding amplitude of level 3 is higher amplitude;

Selectively activate the electrode channel of the corresponding muscle according to the direction of finger movement;

The motion posture information of the prosthetic hand is read every 10 ms. If the current motion posture information is different from the motion posture information read last time, the electrical stimulation mode is re-encoded.

Further, the H-bridge circuit controls the selection of internal channels through the PWM signal output by the single-chip microcomputer, so as to realize the reversal of the polarity of the electrical stimulation waveform.

Further, the signal input terminal of the constant current source circuit is connected to the output terminal DAC out of the DAC module in the microcontroller, and a constant current independent of the load is obtained according to the resistance value of the internal resistance of the circuit and the voltage value of the DAC out.

The beneficial effects of the present invention are: the electrical stimulation system of the present invention is safe and reliable, and works stably; the present invention can feed back the motion posture information of the fingers of the prosthetic limb to the user in the form of electric stimulation in real time; The form is worn on the forearm.

Other advantages, objects and features of the present invention will be set forth in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the investigation and research below, or can be obtained from Get inspiration in the practice of the present invention. The objects and other advantages of the invention may be realized and attained by the following specification.

Description of drawings

In order to make the purpose of the present invention, technical solutions and advantages clearer, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

Fig. 1 is the principle diagram of the wearable electric stimulation system for the sensory feedback of the prosthetic hand movement posture according to the present invention;

Fig. 2 is the application schematic diagram of the wearable electrical stimulation system for prosthetic hand gesture sensory feedback according to the present invention;

Fig. 3 is a flow chart of the use of the wearable electrical stimulation system for sensory feedback of prosthetic hand movement posture according to the present invention.

Detailed ways

Embodiments of the present invention are described below through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific implementation modes, and various modifications or changes can be made to the details in this specification based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the diagrams provided in the following embodiments are only schematically illustrating the basic concept of the present invention, and the following embodiments and the features in the embodiments can be combined with each other in the case of no conflict.

Wherein, the accompanying drawings are for illustrative purposes only, and represent only schematic diagrams, rather than physical drawings, and should not be construed as limiting the present invention; in order to better illustrate the embodiments of the present invention, some parts of the accompanying drawings may be omitted, Enlargement or reduction does not represent the size of the actual product; for those skilled in the art, it is understandable that certain known structures and their descriptions in the drawings may be omitted.

In the drawings of the embodiments of the present invention, the same or similar symbols correspond to the same or similar components; , "front", "rear" and other indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, which are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the referred devices or elements must It has a specific orientation, is constructed and operated in a specific orientation, so the terms describing the positional relationship in the drawings are for illustrative purposes only, and should not be construed as limiting the present invention. For those of ordinary skill in the art, the understanding of the specific meaning of the above terms.

The invention provides a wearable electrical stimulation system for prosthetic hand movement posture sensory feedback, including an arm ring body and an electric stimulator arranged on the arm ring body; the arm ring is made of elastic material, worn on the forearm, and adjusted according to the circumference of the arm The length of the armband makes it fixed on the forearm. Holes are reserved on the armband, and the holes correspond to each electrical stimulation site; the electrical stimulator includes a microcontroller, a power circuit, an H-bridge circuit, a constant current source circuit, and electrodes; the micro-controller The device reads the real-time motion posture information of the prosthetic hand fingers, and sends the corresponding electrical stimulation control command in real time according to the motion posture information. The DAC inside the microcontroller outputs the corresponding voltage signal according to the electrical stimulation control command, and passes through the voltage control constant current source circuit. Finally, a constant current electrical stimulation signal that is not affected by the load resistance is obtained. After the waveform is reversed by the H bridge, a biphasic stimulation waveform of the corresponding frequency and pulse width is obtained; the H bridge circuit controls the internal channel through the PWM signal output by the microcontroller. Select to reverse the polarity of the electrical stimulation waveform. The signal input terminal of the constant current source circuit is connected to the output terminal DAC out of the DAC module, and a constant current independent of the load is obtained according to the resistance value of the internal resistance of the circuit and the voltage value of the DAC out. The power supply circuit is used to convert the +9V DC input voltage into +3.3V, +15V, -15V and 80V DC output voltages, and provide them to the microcontroller, H-bridge circuit and constant current source circuit as working power; each module passes PCB internal wiring connection; the electrode is a self-adhesive electrode sheet, and the negative pole (stimulating electrode) is respectively placed on the extensor hallucis brevis, extensor little finger, extensor finger, flexor hallucis longus, and superficial flexor finger of the forearm, and the positive pole ( The reference electrode) is placed on the inner side of the armband and arranged along the arm. Each electrode site corresponds to the flexion and extension of the five fingers. By selecting the corresponding electrode channel and stimulation parameters, the corresponding muscles are stimulated to make the human body produce corresponding finger movement sensations.

As shown in Figure 1, the neural signal converts the active movement intention of the human body generated by the brain into specific muscle contraction to realize body movements. The finger movement perception of healthy people mainly comes from the muscle spindle sensory nerve transmission induced by the muscle contraction of finger movement. Input, finger movement state (speed, flexion and extension posture) will directly affect the output mode of muscle spindle receptors. But people with physical disabilities cannot perceive the movement state of the prosthetic hand. The surface electrodes are used to provide stimulating current to cause the corresponding forearm muscle and its functional partition muscle fibers to contract, and the muscle spindle receptors form sensory nerve impulses. The target muscle position of the electrical stimulation signal is determined by the prosthetic finger (gesture action mode) participating in the movement. The electrical stimulation signal The output mode (start-end time, strength, etc.) is controlled by the motion phase and posture of the corresponding prosthetic finger, which can realize the sensory feedback pathway of nerve-muscle-prosthetic hand.

Stimulate different forearm muscle groups and their multi-tendinous functional divisions, so that the stimulating current can induce the corresponding muscle contraction, and the corresponding finger flexion and extension motion sensation will be formed due to muscle fiber contraction and muscle spindle receptor excitement; stimulating the extensor hallucis longus can induce thumb The motor sensation of stretching; stimulating the extensor muscles of the index finger can induce the motor sensation of stretching the index finger; stimulating the extensor muscles of the little finger can induce the motor sensation of stretching the little finger; stimulating the middle finger area and the ring finger area of the finger extensor muscles can induce the middle finger and ring finger to do stretching Stimulating the flexor hallucis longus can induce the motion sensation of flexing the thumb; stimulating the index finger area, middle finger area, ring finger area, and little finger area of the superficial flexor finger can induce the flexion movement of the index finger, middle finger, ring finger, and little finger respectively .

The surface electrodes are used to provide stimulating current to cause the corresponding forearm muscle and its functional partition muscle fibers to contract, and the muscle spindle receptors form sensory nerve impulses. The target muscle position of the electrical stimulation signal is determined by the prosthetic finger (gesture action mode) participating in the movement. The electrical stimulation signal The output mode (start-end time, frequency, strength, etc.) of the electrical stimulation signal is controlled by the motion phase and posture of the corresponding prosthetic finger.

As shown on the left side of Figure 2, A is the finger extensor muscle, which starts at the lateral epicondyle of the lower humerus, descends to the rear end of the forearm, and finally divides into four tendons, each tendon points to one finger, and controls the palms of the second to fifth fingers respectively Finger joints and interphalangeal joints do stretching; B is the extensor of the little finger, originating from the lateral epicondyle of the humerus, attached to the dorsal enlargement of the first phalanx of the little finger, and used to control the extension of the little finger; C is the extensor hallucis brevis, originating from the radius , the back of the ulna and the interosseous membrane, inserting on the bottom of the first phalanx of the thumb, and its function is to extend the thumb; D, the flexor hallucis longus, originating from the front of the upper end of the radius and ulna and the interosseous membrane, inserting on the bottom of the last phalanx of the thumb, Its function is to flex the thumb; E is the finger superficial flexor muscle, which starts from the medial epicondyle of the humerus and the front of the upper half of the radius, and ends on both sides of the bottom of the middle phalanx of the 2nd to 5th fingers, and is used to control the metacarpal fingers of the 2nd to 5th fingers Joints and proximal interphalangeal joints flexion. Each marked site on the muscle is where the negative electrode (stimulator electrode) for electrical stimulation is placed.

The actual application diagram of the system is shown on the right side of Figure 2. Wear the armband on the forearm, adjust the length of the armband according to the arm circumference to fix it on the forearm, reserve holes on the armband, and the holes correspond to each electrical stimulation site. A1 at the back of the forearm corresponds to the index finger area of the finger extensor, which controls the extension of the index finger; A2 at the back of the forearm corresponds to the middle finger and ring finger area of the finger extensor, controlling the extension of the middle finger and ring finger; B at the back of the forearm corresponds to the little finger extensor, controlling the extension of the little finger ;C at the back of the forearm corresponds to the extensor pollicis brevis, which controls the extension of the thumb; E1 at the front of the forearm corresponds to the index finger area of the superficial flexor digitorum superficialis, controlling the flexion of the index finger; E2 at the front of the forearm corresponds to the middle finger area of the superficial flexor digitorum superficialis, controlling the flexion of the middle finger; The front E3 corresponds to the ring finger and little finger area of the superficial flexor, which controls the flexion of the ring finger and little finger; the front D of the forearm corresponds to the flexor hallucis longus, which controls the flexion of the thumb. G is the positive electrode (reference electrode) of 8 channels, arranged along the arm. Paste the electrodes according to the position. F on the armband is the electrical stimulator.

The output waveform of the electric stimulator is biphasic square wave; the output frequency range is: 10-100Hz, the precision is 1Hz; the output amplitude range is: 0-15mA, the precision is 0.1mA; the output pulse width is fixed: 100-800μs, the precision 10μs; the number of electrical stimulation output channels is 8 channels, and the parameters of each channel can be adjusted independently.

The microcontroller reads the real-time movement posture information of the prosthetic hand finger according to the encoder of the internal motor of the prosthetic hand finger. The current movement posture information of the prosthetic hand finger includes the movement direction, movement speed, and current position of the prosthetic hand finger.

The microcontroller selects the corresponding electrical stimulation mode according to the real-time motion posture information of the prosthetic hand and fingers and sends corresponding control commands to realize the dynamic regulation of electrical stimulation output (including the selection of electrical stimulation frequency, the selection of electrical stimulation intensity, and the selection of electrical stimulation channels) . Dynamic regulation of electrical stimulation output includes:

The position of the finger is defined according to the angle of the metacarpophalangeal joint of the finger, and the position of the finger is divided into three areas. The degree of muscle contraction is different at different positions. During muscle contraction, the proportion of high-frequency signals in the myoelectricity increases and the proportion of low-frequency signals decreases. Therefore, the frequency of the electrical stimulation output waveform is changed to reflect the position of the finger. The stronger the muscle contraction The higher the frequency of electrical stimulation; when the fingers do stretching exercises, the extensor muscles contract, then zone 1 corresponds to mode 1 with a low frequency, zone 2 corresponds to mode 2 with a medium frequency, zone 3 corresponds to mode 3 with a relatively high frequency; finger flexion When exercising, the flexor muscles contract, the frequency corresponding to Zone 1 is Mode 3, the frequency corresponding to Zone 2 is Mode 2, and the frequency corresponding to Zone 3 is Mode 1;

Divide the angular velocity of finger movement into four grades, when the angular velocity is zero, set it to grade 0, set the slower speed to grade 1, set the medium speed to grade 2, and set the faster speed to grade 3; finger movement The increase of the speed will lead to the increase of the neural activity of the motor cortex, so the angular velocity of the finger movement is reflected by changing the amplitude of the electrical stimulation output. The faster the angular velocity, the higher the amplitude of the electrical stimulation; The corresponding amplitude is lower amplitude, the corresponding amplitude of level 2 is medium amplitude, and the corresponding amplitude of level 3 is higher amplitude;

Selectively activate the electrode channel of the corresponding muscle according to the direction of finger movement;

The motion posture information of the prosthetic hand is read every 10 ms. If the current motion posture information is different from the motion posture information read last time, the electrical stimulation mode is re-encoded.

Figure 3 is a flowchart of the use of the wearable electrical stimulation system. First, EMG signals control prosthetic hand movement. The encoder wiring of the myoelectric prosthetic hand is connected to the IO port of the microcontroller. By setting the IO port to the counter mode to detect the rotation angle of the prosthetic hand finger motor, the current motion posture information of the prosthetic hand finger is obtained accordingly, that is, the prosthetic hand finger Direction of movement, speed of movement, current position. The microcontroller encodes the electrical stimulation pattern according to the motion posture information. The position of the finger is defined according to the angle of the metacarpophalangeal joint of the finger, and the position of the finger is divided into three areas. The degree of muscle contraction is different at different positions. During muscle contraction, the proportion of high-frequency signals in the myoelectricity increases and the proportion of low-frequency signals decreases. By changing the frequency of the electrical stimulation output waveform to reflect the position of the finger, the stronger the muscle contraction The higher the stimulation frequency is; when the fingers do stretching exercises, the extensor muscles contract, then zone 1 corresponds to mode 1 with a low frequency, zone 2 corresponds to mode 2 with a medium frequency, and zone 3 corresponds to mode 3 with a relatively high frequency; finger flexion When the flexor muscles contract, the frequency corresponding to zone 1 is mode three, the frequency corresponding to zone 2 is mode two, and the frequency corresponding to zone 3 is mode one. Divide the angular velocity of finger movement into four grades. When the angular velocity is zero, set it to grade 0, set the slower speed to grade 1, set the medium speed to grade 2, and set the faster speed to grade 3; finger movement The increase of the speed will lead to the increase of the neural activity of the motor cortex. The angular velocity of the finger movement is reflected by changing the amplitude of the electrical stimulation output. The faster the angular velocity, the higher the amplitude of the electrical stimulation; The amplitude is a lower amplitude, the corresponding amplitude of level 2 is a medium amplitude, and the corresponding amplitude of level 3 is a higher amplitude. The electrode channels of the corresponding muscles are selectively activated according to the direction of finger movement. The microcontroller outputs electrical stimulation commands in corresponding modes, and after passing through the H-bridge circuit and the constant current source circuit, the human body is electrically stimulated to realize the sensory feedback function of the motion posture of the prosthetic hand. The motion posture information of the prosthetic hand is read every 10 ms. If the current motion posture information is different from the motion posture information read last time, the electrical stimulation mode is re-encoded.

Stimulation method for inducing single-finger flexion/extension motion sensation: the microcontroller reads the flexion/extension movement of a single finger of the prosthetic hand, and obtains the corresponding electrical stimulation control command; adjusts the output amplitude of the electrical stimulation signal according to the movement speed of the finger; The frequency of the electrical stimulation signal output is adjusted according to the current position of the finger; the electrode channel corresponding to the flexor/extensor muscle of the finger is selected to output the electrical stimulation signal.

Stimulation method to induce fisting movement sensation: the microcontroller reads the fisting movement of the fingers of the prosthetic hand, and obtains the corresponding electrical stimulation control command; adjusts the output amplitude of the electrical stimulation signal according to the movement speed of each finger; adjusts the output amplitude according to the current position of each finger The frequency of the electrical stimulation signal output; select the E1, E2, E3, D electrode channels corresponding to the flexion of the five fingers to output the electrical stimulation signal.

Stimulation method to induce three-finger pair pinch motion sensation: the microcontroller reads the thumb, index finger, and middle finger of the prosthetic hand for three-finger pinch motion, and obtains the corresponding electrical stimulation control command; adjusts the electrical stimulation signal output according to the movement speed of each finger Adjust the frequency of the electrical stimulation signal output according to the current position of each finger; select the E1, E2, and D electrode channels corresponding to the flexion of the thumb, index finger, and middle finger to output the electrical stimulation signal.

Finally, it is noted that the above embodiments are only used to illustrate the technical solutions of the present invention without limitation. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements, without departing from the spirit and scope of the technical solution, should be included in the scope of the claims of the present invention.

Claims (7)

1. A wearable electrical stimulation system for sensory feedback of a hand's locomotor posture, comprising: comprises an arm ring body and an electrical stimulator;

the arm ring body is worn on the forearm and is provided with hole sites corresponding to the electric stimulation sites;

the electro stimulator is arranged on the arm ring body and comprises: the device comprises a microcontroller, a power supply circuit, an H-bridge circuit, a constant current source circuit and electrodes;

the microcontroller reads real-time motion attitude information of the artificial limb fingers and sends corresponding electrical stimulation control commands to the H-bridge circuit and the constant current source circuit according to the motion attitude information;

the power supply circuit is used for converting input voltage into working voltage corresponding to the microcontroller, the H-bridge circuit and the constant current source circuit;

the H-bridge circuit is used for polarity inversion of a stimulation waveform;

the constant current source circuit is used for ensuring that the output current and the stimulation effect are not influenced by the impedance change of the human body;

the electrode is a self-adhesive electrode slice, the negative electrode of the electrode is a stimulating electrode, the positive electrode of the electrode is a reference electrode, the negative electrodes are respectively arranged on extensor hallucis brevis, extensor digitorum minor, extensor digitorum longus and flexor hallucis digitorum superficialis of the forearm, and the positive electrodes are arranged on the inner side of the arm ring and distributed along the circumference of the arm;

the microcontroller selects a corresponding electrical stimulation mode according to the real-time motion posture information of the artificial limb finger and sends a corresponding control command to realize dynamic regulation and control of electrical stimulation output; the electrical stimulation pattern includes: selecting electrical stimulation frequency, selecting electrical stimulation intensity and selecting electrical stimulation channels;

the dynamic regulation of the electrical stimulation output comprises:

the finger position is defined according to the angle of the metacarpophalangeal joints of the fingers and is divided into three areas, wherein 0-30 degrees is a1 area, 30-60 degrees is a2 area, and 60-90 degrees is a 3 area; the muscle contraction degree of the fingers at different positions is different, the high-frequency signal proportion in the myoelectricity is increased and the low-frequency signal proportion in the myoelectricity is reduced when the muscles contract, so that the positions of the fingers are represented by changing the frequency of the electrical stimulation output waveform, and the stronger the muscle contraction is, the higher the electrical stimulation frequency is; when the fingers do stretching movement, extensors contract, and a region 1 corresponds to a mode I with lower frequency, a region 2 corresponds to a mode II with medium frequency, and a region 3 corresponds to a mode III with higher frequency; when the fingers do flexion movement, the flexors contract, and the corresponding frequency of the area 1 is the mode three, the corresponding frequency of the area 2 is the mode two, and the corresponding frequency of the area 3 is the mode one;

dividing the finger motion angular speed into four grades, setting the angular speed as 0 grade when the angular speed is zero, setting the slower speed as 1 grade, setting the medium speed as 2 grade, and setting the faster speed as 3 grade; the increase of the motion speed of the finger can lead the nerve activity of the motor cortex to be enhanced, so that the angular speed of the motion of the finger is reflected by changing the amplitude of the electrical stimulation output, and the electrical stimulation amplitude is higher when the angular speed is higher; the 0-level corresponding amplitude is 0mA, the 1-level corresponding amplitude is lower amplitude, the 2-level corresponding amplitude is medium amplitude, and the 3-level corresponding amplitude is higher amplitude;

selectively activating electrode channels of corresponding muscles according to the motion direction of the finger;

and reading the motion attitude information of the prosthetic hand every 10ms, and if the current motion attitude information is different from the last read motion attitude information, recoding the electrical stimulation mode.

2. A wearable electrical stimulation system for sensory feedback of a hand's locomotor attitude of a prosthetic of claim 1, wherein: the electrodes are arranged at corresponding positions to stimulate different forearm muscle groups and functional partitions of multi-tendon muscles thereof, and the stimulation current induces corresponding muscle contraction, so that corresponding bending and stretching motion feelings of fingers are formed due to muscle fiber contraction and stimulation of muscle spindle receptors; stimulating extensor hallucis longus to induce a motion sensation of thumb extension; stimulating the extensor muscle of the index finger to induce the motion feeling of the extension of the index finger; stimulating the extensor muscles of the little finger to induce the motion feeling of the little finger extension; stimulating the middle finger area and the ring finger area of the extensor muscles of the fingers to respectively induce the feeling of stretching movement of the middle finger and the ring finger; stimulating the flexor hallucis longus to induce a motor sensation of thumb flexion; stimulating the index finger area, middle finger area, ring finger area and little finger area of the superficial flexor of the finger to respectively induce the sense that the index finger, the middle finger, the ring finger and the little finger do flexion movement;

the electrodes are used for providing stimulation current to cause contraction of muscle fibers of forearm muscles corresponding to fingers and functional division muscles of the forearm muscles, muscle shuttle receptors form sensory nerve impulses, the target muscle position of an electrical stimulation signal is determined by the gesture action mode of an artificial limb finger participating in movement, and the output mode of the electrical stimulation signal is controlled by the movement time phase and posture of the corresponding artificial limb finger, wherein the output mode comprises start-end time, frequency and intensity of the electrical stimulation signal.

3. A wearable electrical stimulation system for sensory feedback of a hand's locomotor attitude of a prosthetic of claim 1, wherein: the output waveform of the electric stimulator is a biphase square wave; the output frequency range is 10-100Hz, and the precision is 1Hz; the output amplitude range is 0-15mA, and the precision is 0.1mA; the output pulse width is fixed to be 100-800 mus, and the precision is 10 mus; the number of channels for electrical stimulation output is 8, and parameters of each channel are independently adjusted.

4. A wearable electrical stimulation system for sensory feedback of a hand's locomotor attitude of a prosthetic of claim 1, wherein: and the microcontroller reads the real-time motion attitude information of the artificial hand finger according to the encoder of the motor in the artificial hand finger.

5. A wearable electrical stimulation system for sensory feedback of a hand's motor posture as claimed in claim 3, wherein: the current motion posture information of the artificial finger comprises the motion direction, the motion speed and the current position of the artificial finger.

6. A wearable electrical stimulation system for sensory feedback of a hand's locomotor attitude of a prosthetic of claim 1, wherein: the H-bridge circuit controls the selection of the internal channel through the PWM signal output by the singlechip so as to realize the reversal of the polarity of the electrical stimulation waveform.

7. A wearable electrical stimulation system for sensory feedback of a hand's locomotor attitude of a prosthetic of claim 1, wherein: and the signal input end of the constant current source circuit is connected with the output end DAC out of the DAC module in the microcontroller, and constant current irrelevant to the load is obtained according to the resistance value of the internal resistor of the circuit and the voltage value of the DAC out.

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