Hybrid tactile stimulation system for feeding back artificial limb wrist motion information for amputee

Abstract

The invention relates to a mixed tactile stimulation system for feeding back artificial limb wrist movement information for an amputee, which performs data interaction with a myoelectric artificial limb and provides feeling feedback of wrist movement for a user in real time. The myoelectricity artificial limb comprises a receiving cavity, a myoelectricity collecting electrode and a wrist joint motor with an encoder. The mixed tactile stimulation system comprises an electromyographic signal analog-to-digital conversion module, a motor driving module, a main control module, a tactile stimulation module and a multi-channel mixed tactile stimulation electrode array module. According to the invention, through mixed tactile stimulation, especially electric tactile, the defect of vibration tactile in the aspect of real-time performance is made up, effective transition sense information is provided, and meanwhile, discomfort caused by electric stimulation is reduced. The innovative design not only enhances the sense of ownership and control ability of a user to the artificial limb, but also shortens the time for learning to control the artificial limb, improves the use efficiency of the artificial limb, improves the movement function of an amputee, and improves the use rate of the artificial limb in daily life.

Description

Technical Field

[0001] The invention relates to the technical field of tactile stimulation equipment, and in particular to a hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees. Background Art

[0002] Prosthesis is an effective rehabilitation method for patients with limb disabilities. Surveys show that about 74% of people with limb disabilities say they are willing to consider using prostheses. However, the abandonment rates of myoelectric prostheses in children and adults are 35% and 23% respectively, and the lack of somatosensory feedback is one of the main reasons.

[0003] At present, some technologies have been used to improve the problem of lack of sensory feedback in prosthetic limbs. Sensory substitution technology converts environmental information received by damaged senses into stimulation, which acts on healthy senses, thereby transmitting the original environmental information to the user. These technologies can be divided into two categories based on the interface with the nerves: invasive technologies, such as direct stimulation of nerves through implanted interfaces; and non-invasive technologies, such as skin electrotactile and vibrotactile, which produce sensory feedback by activating different receptors on the skin.

[0004] Using tactile feedback to replace the amputee's sense of movement of the prosthesis is one of the current research methods for prosthetic sensory feedback. With the development of technologies such as sensing and neural interfaces, tactile feedback systems can achieve more accurate, natural and personalized tactile perception transmission. It provides amputees with the ability to perceive the external environment and the position of the prosthesis, helping them to control the movement of the prosthesis more accurately, thereby enhancing their experience of using the prosthesis. Although the tactile feedback system has made some progress, the human tactile system is very complex, and we still need more in-depth research to find more efficient feedback methods.

[0005] At present, there are still the following problems in the research on tactile feedback of prosthetic movement information for amputees:

[0006] 1) The singleness of tactile feedback information. Existing prosthetic tactile feedback systems usually rely on a single type of tactile stimulation (such as vibrotactile or electrotactile). This single mode of feedback flux is insufficient and cannot fully transmit the diverse information required for prosthetic movement, limiting the precise control of prosthetic movement.

[0007] 2) User adaptability and comfort issues. Although vibration stimulation tactile and electrical stimulation tactile feedback are widely used in many prosthetic control systems, the response time of vibration stimulation tactile feedback is long (sometimes up to 400ms), and it performs poorly in fast dynamic movement tasks. And continuous electrical tactile stimulation feedback has a "tingling" or "burning" feeling, which makes it difficult for many users to adapt to it in the long term, which limits its wide application.

[0008] 3) The relationship between tactile stimulation and control accuracy has not been systematically studied. Most existing studies focus on the subjects' perception of tactile stimulation, but rarely combine it with prosthetic fine motor control tasks, which reduces the effectiveness of the prosthetic tactile feedback technology, because the purpose of prosthetic sensory feedback is to improve motor control, and the examination of prosthetic motor control tasks is an important part of the evaluation of prosthetic sensory feedback. Therefore, this limitation hinders the development of tactile technology in prosthetic motor information feedback. Summary of the invention

[0009] The purpose of the present invention is to provide a hybrid tactile stimulation system for feeding back prosthetic wrist movement information to amputees, wherein the hybrid tactile stimulation system interacts with the myoelectric prosthesis to provide the user with sensory feedback of the wrist.

[0010] The myoelectric prosthesis comprises a receiving cavity, a myoelectric acquisition electrode, and a wrist joint motor with an encoder.

[0011] The hybrid tactile stimulation system comprises an electromyographic signal analog-to-digital conversion module, a motor drive module, a main control module, a tactile stimulation module, and a multi-channel hybrid tactile stimulation electrode array module.

[0012] The multi-channel hybrid tactile stimulation electrode array module includes n micro-vibration motors, n electric tactile stimulation electrodes, an FPC connector, and a flexible circuit board, where n is a positive integer.

[0013] The micro vibration motor is used to generate vibration stimulation on the upper arm of the user.

[0014] The electrotactile stimulation electrode is attached to the upper arm of the user of the myoelectric prosthesis to generate electrotactile stimulation on the upper arm of the user.

[0015] The FPC connector connects n micro vibration motors and n electric tactile stimulation electrodes to the tactile stimulation module respectively through wiring, thereby realizing multi-channel output of mixed tactile stimulation.

[0016] One surface of the flexible circuit board is distributed with n micro vibration motors at intervals, and the other surface is distributed with n electric tactile stimulation electrodes at intervals.

[0017] The myoelectric acquisition electrodes acquire two-channel myoelectric signals of a pair of antagonistic muscles in the user's forearm.

[0018] The electromyographic signal analog-to-digital conversion module performs analog-to-digital conversion on the two-channel electromyographic signals to obtain corresponding digital signals, and generates prosthetic movement control instructions based on the digital signals corresponding to the two-channel electromyographic signals.

[0019] The electromyographic signal analog-to-digital conversion module generates a motor drive signal and sends the motor drive signal to the main control module.

[0020] After receiving the motor driving signal, the main control module enables the motor driving module to control the wrist joint motor with an encoder in the myoelectric prosthesis to move according to the prosthesis motion control instruction.

[0021] When the myoelectric prosthesis moves, the encoder of the wrist joint motor with encoder feeds back the motor rotation angle to monitor the prosthesis movement posture information in real time and transmit the prosthesis movement posture information to the main control module.

[0022] The main control module encodes the prosthetic movement posture information into a tactile stimulation pattern, and controls the tactile stimulation module to output a tactile stimulation sequence on the multi-channel mixed tactile stimulation electrode array module.

[0023] Furthermore, the system also includes a power conversion isolation module.

[0024] The power conversion isolation module supplies power to the electromyography acquisition electrodes, the electromyography signal analog-to-digital conversion module, the motor drive module, the wrist joint motor with encoder, the main control module, the tactile stimulation module, and the multi-channel mixed tactile stimulation electrode array module.

[0025] The power conversion isolation module isolates the power supply of the electromyography acquisition electrodes, the electromyography signal analog-to-digital conversion module and the power supply of the motor drive module, the wrist joint motor with encoder, the main control module, the tactile stimulation module, and the multi-channel mixed tactile stimulation electrode array module.

[0026] Furthermore, the prosthetic motion control instructions include the direction and rotation speed of the myoelectric prosthetic wrist joint.

[0027] Furthermore, the movement types of the myoelectric prosthesis include wrist flexion and wrist extension.

[0028] Furthermore, the position of the micro vibration motor on the flexible circuit board corresponds to the position of the electrotactile stimulation electrode.

[0029] Furthermore, the voltage amplitude range received by the micro vibration motor is [0, 3.3V].

[0030] Furthermore, the stimulation intensity range of the electrotactile stimulation electrode is [0,8mA].

[0031] Furthermore, the amplitude range of the tactile stimulation sequence output by the tactile stimulation module is [b, 3.3V], the modulation frequency range is [20Hz, 200Hz], the amplitude range of the electrotactile stimulation sequence is [c, d], the modulation frequency range is [0, 200Hz], wherein b is the vibration sensation threshold, c is the electrotactile sensation threshold, and d is the electrotactile pain threshold.

[0032] Furthermore, the parameters of the vibration stimulation include vibration frequency, vibration duration, vibration intensity, and vibration interval duration.

[0033] Furthermore, the stimulation waveform of the electrotactile stimulation includes a biphasic rectangular pulse.

[0034] The parameters of the electrotactile stimulation include stimulation frequency, stimulation amplitude, stimulation pulse width, and stimulation delay.

[0035] The technical effect of the present invention is unquestionable. The present invention integrates the electric tactile stimulation system and the vibrotactile stimulation system into one system. The system can output stimulation signals of two modes in parallel, which can not only match more abundant prosthetic hand movement types and information, but also fully amplify the advantages of the two modes in information transmission and avoid their disadvantages. For example, the electric tactile stimulation signal is used to transmit the movement process information of the prosthetic hand (avoiding the problem of long response time of vibrotactile stimulation in fast dynamic movement), and the vibrotactile stimulation signal is used to transmit the position information of the prosthetic hand (avoiding the discomfort caused by long-term continuous electric tactile stimulation).

[0036] The present invention uses a hybrid modality tactile alternative feedback method, and effectively improves the comfort and accuracy of induced sensation by rationally allocating feedback strategies for vibrotactile and electrotactile stimulation. At the same time, the present invention adopts a compact structural design, places the vibration motor on the back of the stimulation electrode, increases the stimulation modality without increasing the area of ​​the stimulation interface, and uses a high-precision flexible stimulation electrode array to replace the commonly used disposable hydrogel stimulation electrode, which increases the number of times the electrode is used and reduces the electrode area, thereby increasing the accuracy and resolution of the stimulation, and has good adaptability and stability.

[0037] The present invention provides a compact, portable, and multifunctional hybrid tactile stimulation-control system for prostheses. When amputees undergo rehabilitation training and prosthesis adaptation, the real-time motion information of the prosthetic joints is detected and converted into tactile stimulation to induce a variety of sensations produced by the subjects, so that the subjects can instantly adjust the residual limb electromyographic signals to improve their fine motor control of the prosthesis, thereby enhancing the subjects' sense of ownership of the prosthesis, saving the user's time in learning to control the prosthesis, enhancing the subjects' motor function, and increasing their prosthesis usage rate in daily life.

[0038] The hybrid tactile stimulation-control system provided by the present invention supplements the original myoelectric prosthesis function, and is functionally combined with the control function of the myoelectric prosthesis to form a control-sensation-control closed loop, encapsulating the entire system in a compact myoelectric prosthesis device.

[0039] The hybrid tactile stimulation-control system provided by the present invention is structurally embedded in the receiving cavity of the myoelectric prosthesis, which is convenient to carry and wear. In addition, low-power components and circuit design are used to increase the service life of the system and provide a better user experience.

[0040] The present invention can be applied in the fields of virtual reality, medical rehabilitation, human-computer interaction, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a working schematic diagram of the hybrid tactile stimulation system of the present invention;

[0042] Figure 2 It is a module schematic diagram of the whole system of the present invention;

[0043] Figure 3 A schematic diagram of a hybrid tactile stimulation array module distributed on both sides of a flexible circuit board designed for the present invention; Figure 3 (a) is a schematic diagram of one side of the flexible circuit board where the micro vibration motor array is placed; Figure 3 (b) is a schematic diagram of one side of the flexible circuit board where the electrotactile stimulation electrode array is placed;

[0044] Figure 4 Selecting the type of micro vibration motor used in the present invention;

[0045] Figure 5 This is a schematic diagram of the mapping relationship of the sensory substitution method used in the present invention, Figure 5 (a) is an example diagram of the prosthetic position corresponding to the stimulation position when the prosthetic wrist performs flexion and extension movements; Figure 5 (b) is an example diagram of the corresponding position of the prosthesis motion target in the motion state;

[0046] Figure 6 A schematic diagram of the mixed tactile stimulation strategy used in the present invention;

[0047] In the figure, there are electromyography acquisition electrodes 1, electromyography signal analog-to-digital conversion module 2, motor drive module 3, wrist joint motor with encoder 4, main control module 5, tactile stimulation module 6, multi-channel mixed tactile stimulation electrode array module 7, prosthetic movement posture information 8, micro vibration motor 9, and FPC connector 10. DETAILED DESCRIPTION

[0048] The present invention is further described below in conjunction with the embodiments, but it should not be understood that the above subject matter of the present invention is limited to the following embodiments. Without departing from the above technical ideas of the present invention, various substitutions and changes are made according to the common technical knowledge and customary means in the art, which should all be included in the protection scope of the present invention.

[0049] Embodiment 1:

[0050] See also Figures 1 to 6 A hybrid tactile stimulation system for feeding back prosthetic wrist movement information to amputees, wherein the hybrid tactile stimulation system interacts with the myoelectric prosthesis to provide the user with sensory feedback of the wrist.

[0051] The myoelectric prosthesis comprises a receiving cavity, a myoelectric acquisition electrode 1, and a wrist joint motor 4 with an encoder.

[0052] The hybrid tactile stimulation system includes an electromyographic signal analog-to-digital conversion module 2 , a motor drive module 3 , a main control module 5 , a tactile stimulation module 6 , and a multi-channel hybrid tactile stimulation electrode array module 7 .

[0053] The multi-channel hybrid tactile stimulation electrode array module 7 includes n micro vibration motors 9, n electric tactile stimulation electrodes, an FPC connector 10, and a flexible circuit board, where n is a positive integer.

[0054] The micro vibration motor 9 is used to generate vibration stimulation on the upper arm of the user.

[0055] The electrotactile stimulation electrode is attached to the upper arm of the user of the myoelectric prosthesis to generate electrotactile stimulation on the upper arm of the user.

[0056] The FPC connector 10 connects n micro vibration motors and n electric tactile stimulation electrodes to the tactile stimulation module 6 respectively through wiring, thereby realizing multi-channel output of mixed tactile stimulation.

[0057] One surface of the flexible circuit board is provided with n micro vibration motors 9 at intervals, and the other surface is provided with n electric tactile stimulation electrodes at intervals.

[0058] The myoelectric acquisition electrode 1 acquires two-channel myoelectric signals of a pair of antagonistic muscles in the user's forearm.

[0059] The electromyographic signal analog-to-digital conversion module 2 performs analog-to-digital conversion on the two-channel electromyographic signals to obtain corresponding digital signals, and generates prosthetic movement control instructions based on the digital signals corresponding to the two-channel electromyographic signals.

[0060] The electromyographic signal analog-to-digital conversion module 2 generates a motor drive signal and sends the motor drive signal to the main control module 5 .

[0061] After receiving the motor driving signal, the main control module 5 enables the motor driving module 3 to control the wrist joint motor 4 with an encoder in the myoelectric prosthesis to move according to the prosthesis motion control instruction.

[0062] When the myoelectric prosthesis moves, the encoder of the wrist joint motor 4 with encoder feeds back the motor rotation angle to monitor the prosthesis movement posture information 8 in real time, and transmits the prosthesis movement posture information 8 to the main control module 5.

[0063] The main control module 5 encodes the prosthetic movement posture information 8 into a tactile stimulation pattern, and controls the tactile stimulation module 6 to output a tactile stimulation sequence on the multi-channel mixed tactile stimulation electrode array module 7 .

[0064] Embodiment 2:

[0065] A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the main technical content of which is shown in Example 1. Furthermore, the system also includes a power conversion isolation module.

[0066] The power conversion isolation module supplies power to the electromyography acquisition electrode 1, the electromyography signal analog-to-digital conversion module 2, the motor drive module 3, the wrist joint motor with encoder 4, the main control module 5, the tactile stimulation module 6, and the multi-channel mixed tactile stimulation electrode array module 7.

[0067] The power conversion isolation module isolates the power supply of the electromyography acquisition electrode 1, the electromyography signal analog-to-digital conversion module 2 and the power supply of the motor drive module 3, the wrist joint motor with encoder 4, the main control module 5, the tactile stimulation module 6, and the multi-channel mixed tactile stimulation electrode array module 7.

[0068] Embodiment 3:

[0069] A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the main technical content of which is shown in any one of Examples 1 to 2. Furthermore, the prosthetic motion control instructions include the direction and rotation speed of the myoelectric prosthetic wrist joint.

[0070] Embodiment 4:

[0071] A hybrid tactile stimulation system for feeding back prosthetic wrist movement information to amputees, the main technical content of which is shown in any one of Examples 1 to 3. Furthermore, the movement types of the myoelectric prosthesis include wrist flexion and wrist extension.

[0072] Embodiment 5:

[0073] A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the main technical content of which is shown in any one of Examples 1 to 4. Furthermore, the position of the micro-vibration motor 9 on the flexible circuit board corresponds to the position of the electric tactile stimulation electrode.

[0074] Embodiment 6:

[0075] A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the main technical content of which is shown in any one of Examples 1 to 5. Furthermore, the voltage amplitude range received by the micro vibration motor 9 is [0, 3.3V].

[0076] Embodiment 7:

[0077] A hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees, the main technical contents of which are shown in any one of Examples 1 to 6. Furthermore, the stimulation intensity range of the electrotactile stimulation electrode is [0,8mA].

[0078] Embodiment 8:

[0079] A hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees, wherein the main technical contents are shown in any one of Examples 1 to 7. Furthermore, the tactile stimulation sequence output by the tactile stimulation module 6 has an amplitude range of [b, 3.3 V] and a modulation frequency range of [20 Hz, 200 Hz], and an amplitude range of [c, d] and a modulation frequency range of [0, 200 Hz], wherein b is the vibration sensation threshold, c is the electrotactile sensation threshold, and d is the electrotactile pain threshold.

[0080] Embodiment 9:

[0081] A hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees, wherein the main technical contents are shown in any one of Examples 1 to 8. Furthermore, the parameters of the vibration stimulation include vibration frequency, vibration duration, vibration intensity, and vibration interval duration.

[0082] Embodiment 10:

[0083] A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the main technical content of which is shown in any one of Examples 1 to 9. Furthermore, the stimulation waveform of the electrotactile stimulation includes a biphasic rectangular pulse.

[0084] The parameters of the electrotactile stimulation include stimulation frequency, stimulation amplitude, stimulation pulse width, and stimulation delay.

[0085] Embodiment 11:

[0086] See also Figures 1 to 6 A hybrid tactile stimulation system for feeding back prosthetic wrist movement information to amputees, wherein the hybrid tactile stimulation system interacts with the myoelectric prosthesis to provide the user with sensory feedback of the wrist.

[0087] The myoelectric prosthesis comprises a receiving cavity, a myoelectric acquisition electrode 1, and a wrist joint motor 4 with an encoder.

[0088] The hybrid tactile stimulation system includes an electromyographic signal analog-to-digital conversion module 2 , a motor drive module 3 , a main control module 5 , a tactile stimulation module 6 , and a multi-channel hybrid tactile stimulation electrode array module 7 .

[0089] The multi-channel hybrid tactile stimulation electrode array module 7 includes n micro vibration motors 9, n electric tactile stimulation electrodes, an FPC connector 10, and a flexible circuit board, where n is a positive integer.

[0090] The micro vibration motor 9 is used to generate vibration stimulation on the upper arm of the user.

[0091] The micro vibration motor is a rotor motor with a diameter of 10 mm, a thickness of 2.7 mm, a rated speed of 11000±2500 rpm, a rated working voltage of 3.0 V, and a rated current of 80 mA.

[0092] The micro vibration motor is driven by PWM square wave. The user can change the duty cycle of the PWM acting on the motor, thereby changing the effective voltage at both ends of the motor, and finally achieving the purpose of changing the vibration intensity of the motor. Each motor can achieve independent control of parameters.

[0093] The electrotactile stimulation electrode is attached to the upper arm of the user of the myoelectric prosthesis to generate electrotactile stimulation on the upper arm of the user.

[0094] The electrotactile stimulation is output by thin film electrodes in combination with hydrogel, and the stimulation waveform is a biphasic rectangular pulse, and the parameters include stimulation frequency, stimulation amplitude, stimulation pulse width, and stimulation delay.

[0095] The FPC connector 10 connects n micro vibration motors and n electric tactile stimulation electrodes to the tactile stimulation module 6 respectively through wiring, thereby realizing multi-channel output of mixed tactile stimulation.

[0096] One surface of the flexible circuit board is provided with n micro vibration motors 9 at intervals, and the other surface is provided with n electric tactile stimulation electrodes at intervals.

[0097] The multi-channel hybrid tactile stimulation electrode array module 7 is a two-layer flexible circuit board made of a material with good flexibility, with a thickness of 0.12mm±0.03mm, a yellow covering film, and a copper surface material, which can fit the user's skin tightly.

[0098] The size of the flexible circuit board conforms to the arm circumference length range of an adult human upper limb, and a single size is 112.5 mm*73 mm.

[0099] like Figure 3 As shown, the flexible stimulation electrode array is mainly composed of a micro vibration motor 9, an electrotactile stimulation electrode, an FPC connector 10 and a flexible circuit board. It is composed of a silicon substrate, a thin film electrode and a micro vibration motor. It has the advantages of simple structure, stable output signal, accurate frequency response, etc. Each stimulation electrode is spaced 26 mm apart to meet the two-point threshold that can be perceived by the human body.

[0100] The myoelectric acquisition electrode 1 acquires two-channel myoelectric signals of a pair of antagonistic muscles in the user's forearm.

[0101] The electromyographic signal analog-to-digital conversion module 2 performs analog-to-digital conversion on the two-channel electromyographic signals to obtain corresponding digital signals, and generates prosthetic movement control instructions based on the digital signals corresponding to the two-channel electromyographic signals.

[0102] The prosthetic motion control command is generated as follows: compare the amplitudes of the two channel signals. If the amplitude of channel A is higher than a certain threshold of channel B, a motor forward command is generated, otherwise a motor reverse command is generated. The specific threshold is adjusted according to the strength of the user's electromyographic signal.

[0103] The electromyographic signal analog-to-digital conversion module 2 generates a motor drive signal and sends the motor drive signal to the main control module 5 .

[0104] The electromyographic signal analog-to-digital conversion module 2 determines the difference in amplitude between the two-channel electromyographic signals, generates a prosthetic motion control instruction, and sends a motor drive signal to the main control module 5 .

[0105] The electromyographic signal analog-to-digital conversion module 2 uses the STM32F103RCT6 chip, with a variety of built-in peripherals, including analog-to-digital converters, timers, interrupt controllers, digital interface integrated circuits, and various communication interfaces, which can help users achieve more flexible and complex functions. It is an embedded system with the advantages of high performance, low cost, and low power consumption, which can provide control signals for this design.

[0106] After receiving the motor driving signal, the main control module 5 enables the motor driving module 3 to control the wrist joint motor 4 with an encoder in the myoelectric prosthesis to move according to the prosthesis motion control instruction.

[0107] The motor drive module 3 is implemented by the DC motor drive chip L293B, which contains 4 independent drivers. The motor supply voltage can reach up to 36V and can provide an output current of 1A. In this design, in order to realize the forward and reverse rotation of the motor, the drivers 1 and 2 are combined into a group to drive the motor at hand. The logic part of the module is powered by 5V, and the logic input can be provided by the IO pin 3.3V of the microcontroller. The module's turn-on time is 750ns and the turn-off time is 200ns. The chip fully meets the PWM control of the motor.

[0108] When the myoelectric prosthesis moves, the encoder of the wrist joint motor 4 with encoder feeds back the motor rotation angle to monitor the prosthesis movement posture information 8 in real time, and transmits the prosthesis movement posture information 8 to the main control module 5.

[0109] The main control module 5 encodes the prosthetic movement posture information 8 into a tactile stimulation pattern, and controls the tactile stimulation module 6 to output a tactile stimulation sequence on the multi-channel mixed tactile stimulation electrode array module 7 .

[0110] The vibration stimulation part realizes the selection of the vibration channel through the 74LVC1G157GW multiplexer chip. When a high level is provided to the Select end of the chip, the PWM signal at the Input end will be output to the Y end, thereby reaching the gate of AO3400. Therefore, at the high level of the PWM wave, the 3.3V voltage of the drain will be given to the vibration motor connected to the source, realizing the function of controlling the motor output stimulation.

[0111] The workflow of the hybrid tactile stimulation and motor control system is as follows:

[0112] 1) placing a multi-channel flexible stimulation electrode array on the user's upper arm, and wearing the myoelectric prosthesis on the limb;

[0113] 2) Place electromyographic acquisition electrodes at a pair of antagonistic muscles on the user's forearm, and realize wrist flexion and extension movement of the myoelectric prosthesis by measuring the amplitude of the electromyographic signals of the two muscles;

[0114] 3) The encoder reads the motor rotation angle information in real time to monitor the prosthesis motion posture information in real time and transmits the information to the main control module;

[0115] 4) The main control module controls the tactile stimulation module through a specific communication method, selects the stimulation output channel and sets the stimulation parameters; the vibration stimulation parameters include vibration frequency, vibration duration, vibration intensity, and vibration interval duration; the stimulation waveform of the electrotactile stimulation is a biphasic rectangular pulse, and the parameters include stimulation frequency, stimulation amplitude, stimulation pulse width, and stimulation delay.

[0116] 5) After receiving the output signal, the multi-channel flexible vibration stimulation electrode array generates a specific mixed tactile stimulation acting on the upper arm of the prosthesis user;

[0117] 6) After the user's upper limbs feel the tactile stimulation, they perform the corresponding action of the stimulation or record the corresponding action of the current stimulation. The main control module detects the motor rotation state in real time and adjusts the stimulation parameters accordingly, and returns to step 4) until the current action is completed.

[0118] Embodiment 12:

[0119] A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the main technical content of which is shown in Example 11. Furthermore, the system also includes a power conversion isolation module.

[0120] The power conversion isolation module supplies power to the electromyography acquisition electrode 1, the electromyography signal analog-to-digital conversion module 2, the motor drive module 3, the wrist joint motor with encoder 4, the main control module 5, the tactile stimulation module 6, and the multi-channel mixed tactile stimulation electrode array module 7.

[0121] The power conversion isolation module is a module that provides power support. It is powered by an 8V rechargeable battery that comes with the prosthesis. Each circuit obtains the corresponding voltage power supply through the designed voltage conversion module: the power supply voltage of the electromyographic signal analog-to-digital conversion module, the main control module and the Bluetooth communication module is 3.3V, the power supply voltage of the electromyographic acquisition electrode and the drive module is 5V, and the vibration motor is within the rated working voltage range. 3.3V voltage is selected for power supply. The size of the electrotactile stimulation is controlled by a constant current source. Since the human body impedance size is floating, in order to ensure that the current size within the preset range can be provided, a 70V voltage needs to be provided. Therefore, the system designs multiple voltage conversion circuits, which are 8V to 12V, 12V to 70V, 12V to 5V and 5V to 3.3V.

[0122] The chip used in the 8V to 12V circuit is TPS61089RNRR, and its maximum output current of 7A can meet the power requirements of the system.

[0123] The 12V to 70V circuit adopts a DCDC switching power supply, and the circuit topology is a Boost circuit with feedback. The voltage level of this circuit is relatively high, and the system uses the MCP1650S chip, which can raise the voltage to more than 100V, and the allowed output is 5W, and the working quiescent current is 120μA, which meets the design requirements.

[0124] The 12V to 5V converter uses a high-performance Buck DCDC chip TPS563201 produced by Texas Instruments. The input voltage range of this chip is 2.95V to 17V, and the output voltage can be adjusted according to the external circuit, usually between 0.8V and 6V. This circuit sets the output voltage to 5V by setting the two sets of resistor values ​​connected to the VFB interface, and the output current can reach up to 3A.

[0125] The chip used in the 5V to 3.3V circuit is TLV70433, which is a low voltage drop linear regulator chip with low voltage drop and low quiescent current. It can be used to convert the input voltage from 3.5V to 28V down to the output voltage of 1.2V to 5.5V. The circuit using TLV70433 is very simple and easy to design, which can reduce the number of components and cost in the system.

[0126] The power conversion isolation module isolates the power supply of the electromyography acquisition electrode 1, the electromyography signal analog-to-digital conversion module 2 and the power supply of the motor drive module 3, the wrist joint motor with encoder 4, the main control module 5, the tactile stimulation module 6, and the multi-channel mixed tactile stimulation electrode array module 7.

[0127] The power isolation function achieves 12V-12V DCDC isolation through the isolation module URB2412YMD-10WR3, and its output power can reach 10W. The power isolation module is used to separate the power supply from the subsequent application circuit, with an isolation voltage of up to 1500VDC, which improves system safety.

[0128] The myoelectric prosthesis also includes a rechargeable battery.

[0129] The battery voltage is 8V, is rechargeable, and is the power supply for the entire system.

[0130] Embodiment 13:

[0131] A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the main technical content of which is shown in any one of Examples 11 to 12. Furthermore, the prosthetic motion control instructions include the direction and rotation speed of the myoelectric prosthetic wrist joint.

[0132] The motor drive module is implemented by the DC motor driver chip L293B, which contains 4 independent drivers. The motor supply voltage can reach up to 36V and can provide an output current of 1A. In this design, in order to realize the forward and reverse rotation of the motor, drivers 1 and 2 are combined into a group to drive the motor at hand. The logic part of the module is powered by 5V, and the logic input can be provided by the IO pin 3.3V of the microcontroller. The module's turn-on time is 750ns and the turn-off time is 200ns. The chip fully meets the PWM control of the motor.

[0133] Embodiment 14:

[0134] A hybrid tactile stimulation system for providing feedback of prosthetic wrist movement information to amputees, wherein the main technical contents are shown in any one of Examples 11 to 13. Furthermore, the movement types of the myoelectric prosthesis include wrist flexion and wrist extension, and the angle range is 0° to 60°.

[0135] Embodiment 15:

[0136] A hybrid tactile stimulation system for feeding back prosthetic wrist movement information to amputees, the main technical content of which is shown in any one of Examples 11 to 14. Furthermore, the position of the micro-vibration motor 9 on the flexible circuit board corresponds to the position of the electric tactile stimulation electrode.

[0137] A layer of copper film is plated on the surface of the flexible circuit board.

[0138] The multi-channel mixed tactile stimulation electrode array module 7 is a two-layer flexible circuit board made of a material with good flexibility and can fit closely to the user's skin.

[0139] The thickness of the flexible circuit board is 0.12 mm, and the surface is plated with a layer of copper film, a yellow covering film, and the surface is copper material.

[0140] The size of the flexible circuit board conforms to the arm circumference length range of an adult human upper limb, and a single size is 112.5 mm*73 mm.

[0141] Embodiment 16:

[0142] A hybrid tactile stimulation system for providing feedback of prosthetic wrist movement information to amputees, wherein the main technical contents are shown in any one of Examples 11 to 15. Furthermore, the voltage amplitude range received by the micro vibration motor 9 is [0, 3.3 V].

[0143] Embodiment 17:

[0144] A hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees, the main technical contents of which are shown in any one of Examples 11 to 16. Furthermore, the stimulation intensity range of the electrotactile stimulation electrode is [0,8mA].

[0145] Embodiment 18:

[0146] A hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees, wherein the main technical contents are shown in any one of Examples 11 to 17. Furthermore, the tactile stimulation sequence output by the tactile stimulation module 6 has an amplitude range of [b, 3.3 V] and a modulation frequency range of [20 Hz, 200 Hz], and an amplitude range of [c, d] and a modulation frequency range of [0, 200 Hz], wherein b is the vibration sensation threshold, c is the electrotactile sensation threshold, and d is the electrotactile pain threshold.

[0147] The vibration perception threshold is measured by increasing the vibration amplitude from 0 in a certain gradient until the subject begins to report feeling stimulation, and the current amplitude is recorded as the perception threshold.

[0148] The electrotactile sensation threshold is measured by increasing the electrical stimulation amplitude from 0 in a certain gradient until the subject begins to report feeling stimulation, and recording the current amplitude as the sensation threshold. The electrical stimulation amplitude is continued to be increased until the subject begins to report discomfort, and recording the current amplitude as the pain threshold.

[0149] Embodiment 19:

[0150] A hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees, wherein the main technical contents are shown in any one of Examples 11 to 18. Furthermore, the parameters of the vibration stimulation include vibration frequency, vibration duration, vibration intensity, and vibration interval duration.

[0151] Embodiment 20:

[0152] A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the main technical content of which is shown in any one of Examples 11 to 19. Furthermore, the stimulation waveform of the electrotactile stimulation includes a biphasic rectangular pulse.

[0153] The parameters of the electrotactile stimulation include stimulation frequency, stimulation amplitude, stimulation pulse width, and stimulation delay.

[0154] Embodiment 21:

[0155] A hybrid tactile stimulation system for providing feedback of prosthetic wrist movement information to amputees, wherein the main technical contents are shown in any one of Examples 11 to 20. Furthermore, the system is embedded in a myoelectric prosthesis and electrically connected to the myoelectric prosthesis, and provides different modes of hybrid tactile stimulation according to the kinematic parameters of the prosthesis, thereby helping the user to obtain sensory feedback while manipulating the prosthesis.

[0156] When the four positions of wrist flexion and extension are mapped to the electrotactile sensation induced by different channels of the hybrid tactile electrode array, static position sensation and dynamic isokinetic movement sensation are established based on the timing established according to the stimulation positions.

[0157] The flexible hybrid tactile electrode array includes 4 micro vibration motors and 4 electrotactile stimulation electrodes, which are respectively recorded as vibration channels: VCH1, VCH2, VCH3, VCH4. Electrotactile stimulation channels: ECH1, ECH2, ECH3, ECH4. The vibration and electrotactile stimulation of the same channel number are at the same position of the electrode array. The two electrodes on the back of the upper arm correspond to the wrist extension direction of the prosthetic wrist, and the two electrodes on the palm side correspond to the wrist flexion direction. The larger the angle of movement, the farther the activated stimulation channel is from the central axis.

[0158] Use different modes of tactile stimulation to map the motion posture information of the myoelectric prosthesis. When the position of the myoelectric prosthesis motion posture information is E30, channels VCH1 and ECH1 are stimulated; when the position is E15, channels VCH2 and ECH2 are stimulated; when the position is F15, channels VCH3 and ECH3 are stimulated; when the position is F30, channels VCH4 and ECH4 are stimulated. E and F represent wrist extension and wrist flexion, respectively, and 15 and 30 represent motion angles of 15° and 30°, respectively. The stimulated channel changes with the change of the prosthesis angle.

[0159] In the mapping mode of the hybrid tactile stimulation channel and the isokinetic motion information of the prosthesis, the frequency of the electrotactile stimulation of each channel is fixed, ranging from [0,200Hz], and the stimulation intensity is fixed, ranging from [0,8mA]. The duration of the vibration stimulation is 2 seconds, and the stimulation frequency and intensity are fixed. When the prosthesis stays at the target position, the electrotactile stimulation will be turned off after 0.5 seconds, and the vibrotactile stimulation will be turned off after 2 seconds.

[0160] The design of this hybrid tactile feedback mode can use the real-time nature of electrotactile to provide subjects with instant position information, especially during the movement of the prosthesis, electrotactile can allow subjects to perceive position changes in a timely manner. For example, during the process of wrist flexion of the prosthesis from position E30 to position F30, the real-time response of electrotactile can allow subjects to perceive that they have passed through key positions such as E15 and F15, thereby avoiding missing feedback from intermediate positions due to the long response time of vibrotactile, and reducing confusion in position perception.

[0161] When the prosthesis stays at the target position, the electric touch is turned off after 500ms, which can effectively reduce the discomfort caused by long-term electrical stimulation and the interference to the electromyographic signal. After that, the vibrotactile sense continues to provide position confirmation information, which not only avoids the disadvantage of poor real-time performance of vibrotactile sense, but also gives full play to the advantages of vibrotactile sense in comfort and low interference to the electromyographic signal.

[0162] Embodiment 22:

[0163] A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the main technical content of which is shown in any one of Embodiments 11 to 21. Further, a method for reconstructing wrist proprioception based on sensory substitution is as follows:

[0164] This method achieves the reconstruction of the angle and speed of wrist flexion and extension in different ways; the four positions of wrist flexion and extension are mapped to the tactile sensation induced by different channels of the electrotactile electrode, on this basis, the isokinetic movement sensation is established. The three speeds of wrist flexion and extension are mapped to the tactile sensation induced by different frequencies of the vibration electrode, on this basis, the variable speed movement sensation is established;

[0165] When the position of the myoelectric prosthesis movement posture information is ST, it is the initial position without stimulation. When the position is E30, the electrotactile channel 1 is stimulated. When the position is E15, the electrotactile channel 2 is stimulated. When the position is F15, the electrotactile channel 3 is stimulated. When the position is F30, the electrotactile channel 4 is stimulated. E and F represent wrist extension and wrist flexion, respectively. 15 and 30 represent movement angles of 15° and 30°, respectively. The stimulated channel changes with the change of the prosthesis angle.

[0166] When the myoelectric prosthesis movement posture information is wrist flexion, the electrotactile stimulation is performed in the channel in a clockwise order. The larger the angle, the farther the stimulated channel is from the central axis; the vibrotactile stimulation activates channel 3 and channel 4 at the same time.

[0167] When the myoelectric prosthesis movement posture information is wrist extension, the electrotactile stimulation is performed in the channel counterclockwise in sequence, and the larger the angle, the farther the stimulated channel is from the central axis; the vibrotactile stimulation activates channel 1 and channel 2 at the same time.

[0168] When the myoelectric prosthesis motion posture information is high speed, the vibration stimulation is correspondingly set to high frequency; when the myoelectric prosthesis motion posture information is medium speed, the vibration stimulation is correspondingly set to medium frequency; when the myoelectric prosthesis motion posture information is low speed, the vibration stimulation is correspondingly set to low frequency.

[0169] Embodiment 23:

[0170] See also Figures 1 to 6 A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the system includes a main control module, a motor drive module, a tactile stimulation module, and a hybrid tactile stimulation electrode array module, which are embedded in a myoelectric prosthesis to provide sensory feedback to the user.

[0171] The myoelectric prosthesis comprises a receiving cavity, a wrist joint motor with an encoder, an electromyographic signal analog-to-digital conversion module, electromyographic acquisition electrodes, and a rechargeable battery.

[0172] The electromyographic signal analog-to-digital conversion module is electrically connected to the motor drive module to set the drive motor to rotate forward or reverse, adjust the rotation speed, etc., to control the prosthesis to perform corresponding movements.

[0173] The main control module is electrically connected to the tactile stimulation module, selects a tactile stimulation channel and sets stimulation parameters according to the working state of the motor, and generates mixed tactile stimulation acting on the upper arm of the prosthesis user.

[0174] The main control module controls n vibration output channels and n electrotactile stimulation output channels of the stimulator, and each vibration output channel is connected to a vibration motor.

[0175] The vibration electrode array includes n micro vibration motors fixed at predetermined intervals on the pre-set positions of the flexible printed board, and the back side of the vibration electrode array is the electric tactile stimulation electrode.

[0176] The tactile stimulation array is electrically connected to the tactile stimulator via a flat cable and an FPC connector, and is in close contact with the user's upper arm to output mixed tactile stimulation.

[0177] The hybrid tactile stimulation-control system includes the following components: a main control module, a motor drive module, a tactile stimulation module, a hybrid tactile stimulation electrode array module, and a power conversion isolation module, and has the advantages of miniaturization and portability.

[0178] The workflow of the tactile stimulation and motor control system is as follows:

[0179] 1) placing a multi-channel flexible stimulation electrode array on the user's upper arm, and wearing the myoelectric prosthesis on the limb;

[0180] 2) Place electromyographic acquisition electrodes at a pair of antagonistic muscles on the user's forearm, and realize wrist flexion and extension movement of the myoelectric prosthesis by measuring the amplitude of the electromyographic signals of the two muscles;

[0181] 3) The encoder reads the motor rotation angle information in real time to monitor the prosthetic limb motion posture information in real time and transmits the information to the main control module;

[0182] 4) The main control module controls the tactile stimulation module through a specific communication method, selects the stimulation output channel and sets the stimulation parameters; the vibration stimulation parameters include vibration frequency, vibration duration, vibration intensity, and vibration interval duration; the stimulation waveform of the electrotactile stimulation is a biphasic rectangular pulse, and the parameters include stimulation frequency, stimulation amplitude, stimulation pulse width, and stimulation delay.

[0183] 5) After receiving the output signal, the multi-channel flexible vibration stimulation electrode array generates a specific mixed tactile stimulation acting on the upper arm of the prosthesis user;

[0184] 6) After the user's upper limbs feel the tactile stimulation, they perform the corresponding action of the stimulation or record the corresponding action of the current stimulation. The main control module detects the motor rotation state in real time and adjusts the stimulation parameters accordingly, and returns to step 4) until the current action is completed.

[0185] The prosthetic wrist movement posture types include wrist flexion and wrist extension, and the angle range is 0° to 60°.

[0186] The multi-channel mixed tactile stimulation electrode array module 7 is a two-layer flexible circuit board made of a material with good flexibility and can fit closely to the user's skin.

[0187] The thickness of the flexible circuit board is 0.12 mm, and the surface is plated with a layer of copper film, a yellow covering film, and the surface is copper material.

[0188] The size of the flexible circuit board conforms to the arm circumference length range of an adult human upper limb, and a single size is 112.5 mm*73 mm.

[0189] The system is powered by an 8V rechargeable battery, which is embedded in the prosthesis receiving cavity. The stimulation intensity range of the micro vibration motor is [0,3.3V].

[0190] The amplitude range of the vibration stimulator output is [sensation threshold, 3.3V], and the modulation frequency range is [20, 200Hz]. The amplitude range of the electrotactile stimulation sequence is [sensation threshold, pain threshold], and the modulation frequency range is [0, 200Hz].

[0191] A method of wrist proprioception reconstruction based on sensory substitution:

[0192] The method for reconstructing wrist proprioception based on sensory substitution is characterized in that: the method realizes the reconstruction of the angle and speed of wrist flexion and extension in different ways; the four positions of wrist flexion and extension are mapped to the tactile sensation induced by different channels of the electrotactile electrode, on this basis, the isokinetic movement sensation is established. The three speeds of wrist flexion and extension are mapped to the tactile sensation induced by different frequencies of the vibrating electrode, on this basis, the variable speed movement sensation is established;

[0193] When the position of the myoelectric prosthesis motion posture information is ST, it is the initial position without stimulation. When the position is E30, the electrotactile channel 1 is stimulated. When the position is E15, the electrotactile channel 2 is stimulated. When the position is F15, the electrotactile channel 3 is stimulated. When the position is F30, the electrotactile channel 4 is stimulated. E and F represent wrist extension and wrist flexion, respectively. 15 and 30 represent motion angles of 15° and 30°, respectively. The stimulated channel changes with the change of the prosthesis angle.

[0194] When the myoelectric prosthesis movement posture information is wrist flexion, the electrotactile stimulation is performed in the channel in a clockwise order. The larger the angle, the farther the stimulated channel is from the central axis; the vibrotactile stimulation activates channel 3 and channel 4 at the same time.

[0195] When the myoelectric prosthesis movement posture information is wrist extension, the electrotactile stimulation is performed in the channel counterclockwise in sequence, and the larger the angle, the farther the stimulated channel is from the central axis; the vibrotactile stimulation activates channel 1 and channel 2 at the same time.

[0196] When the myoelectric prosthesis motion posture information is high speed, the vibration stimulation is correspondingly set to high frequency; when the myoelectric prosthesis motion posture information is medium speed, the vibration stimulation is correspondingly set to medium frequency; when the myoelectric prosthesis motion posture information is low speed, the vibration stimulation is correspondingly set to low frequency.

[0197] Embodiment 24:

[0198] See also Figures 1 to 6 A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the system includes a main control module, a motor drive module, a tactile stimulation module, and a hybrid tactile stimulation electrode array module, which are embedded in a myoelectric prosthesis to provide sensory feedback to the user.

[0199] The hybrid tactile stimulation system is embedded in the receiving cavity inside the myoelectric prosthesis when in use, and the stimulation output part is closely connected to the user's arm, which is the core component for generating tactile stimulation.

[0200] The main control module uses STM32F103RCT6 as the main control chip, which is an embedded system with the advantages of high performance, low cost, low power consumption, etc., and can provide control signals for this design.

[0201] The vibration stimulation part in the hybrid tactile stimulation module realizes the selection of the vibration channel through the 74LVC1G157GW multiplexer chip. When a high level is provided to the Select end of the chip, the PWM signal at the Input end will be output to the Y end, thereby reaching the gate of AO3400. Therefore, at the high level of the PWM wave, the 3.3V voltage of the drain will be given to the vibration motor connected to the source, realizing the function of controlling the motor output stimulation.

[0202] The power conversion isolation module is a module that provides power support and is powered by a rechargeable battery that comes with the prosthesis. Each circuit obtains corresponding voltage power through a designed voltage conversion module.

[0203] The myoelectric prosthesis comprises a receiving cavity, a wrist joint motor with an encoder, an electromyographic signal analog-to-digital conversion module, and electromyographic collection electrodes.

[0204] The motor drive module realizes the movement of the myoelectric prosthesis by controlling the direction and speed of the wrist joint motor with an encoder in the myoelectric prosthesis.

[0205] The main control module is electrically connected to the tactile stimulation module, and the stimulation parameters are set according to the working state of the motor: the intensity, frequency and mode of the vibration and electrical tactile stimulation are adjusted, which can be achieved by using buttons, switches or programmable electronic control systems to produce mixed tactile stimulation acting on the upper arm of the prosthesis user.

[0206] The hybrid tactile stimulation electrode array is made of a flexible circuit board, consisting of a silicon substrate, a thin film electrode and a micro vibration motor. It can fit perfectly with the user's upper arm and is safe and portable. It has a higher degree of integration and is more systematic than discrete vibration devices.

[0207] The flexible electrode array is electrically connected to the tactile stimulator via a flat cable and an FPC connector, and contacts the upper arm of the user to transmit tactile stimulation.

[0208] The vibrating electrode array uses a 2-layer flexible circuit board with a thickness of 0.12mm±0.03mm, a yellow covering film, a copper surface material, and a single size of 112.5mm*73mm, which is consistent with the arm circumference length range of an adult human upper limb.

[0209] The micro vibration motor is a rotor motor with a diameter of 10 mm, a thickness of 2.7 mm, a rated speed of 11000±2500 rpm, a rated working voltage of 3.0 V, and a rated current of 80 mA.

[0210] The micro vibration motor is driven by PWM square wave. The user can change the duty cycle of the PWM acting on the motor, thereby changing the effective voltage at both ends of the motor, and finally achieving the purpose of changing the vibration intensity of the motor. Each motor can achieve independent control of parameters.

[0211] The workflow of the vibration stimulation and motor control system is as follows:

[0212] 1) placing a multi-channel flexible stimulation electrode array on the user's upper arm, and wearing the myoelectric prosthesis on the limb;

[0213] 2) Place electromyographic acquisition electrodes at a pair of antagonistic muscles on the user's forearm, and realize wrist flexion and extension movement of the myoelectric prosthesis by measuring the amplitude of the electromyographic signals of the two muscles;

[0214] 3) The encoder reads the motor rotation angle information in real time to monitor the prosthetic limb motion posture information in real time and transmits the information to the main control module;

[0215] 4) The main control module controls the tactile stimulation module through a specific communication method, selects the stimulation output channel and sets the stimulation parameters; the vibration stimulation parameters include vibration frequency, vibration duration, vibration intensity, and vibration interval duration; the stimulation waveform of the electrotactile stimulation is a biphasic rectangular pulse, and the parameters include stimulation frequency, stimulation amplitude, stimulation pulse width, and stimulation delay.

[0216] 5) After receiving the output signal, the multi-channel flexible vibration stimulation electrode array generates a specific mixed tactile stimulation acting on the upper arm of the prosthesis user;

[0217] 6) After the user's upper limbs feel the tactile stimulation, they perform the corresponding action of the stimulation or record the corresponding action of the current stimulation. The main control module detects the motor rotation state in real time and adjusts the stimulation parameters accordingly, and returns to step 4) until the current action is completed.

[0218] The prosthetic wrist movement posture types include wrist flexion and wrist extension, and the angle range is 0° to 60°.

[0219] The system is powered by an 8V rechargeable battery, which is embedded in the prosthesis receiving cavity. The stimulation intensity range of the micro vibration motor is [0,3.3V].

[0220] The amplitude range of the vibration stimulator output is [sensation threshold, 3.3V], and the modulation frequency range is [20, 200Hz]. The amplitude range of the electrotactile stimulation sequence is [sensation threshold, pain threshold], and the modulation frequency range is [0, 200Hz].

[0221] A method for wrist proprioception reconstruction based on sensory substitution:

[0222] 1) When the position of the myoelectric prosthesis motion posture information is ST, it is the initial position without stimulation, when the position is E30, the electrotactile channel 1 is stimulated, when the position is E15, the electrotactile channel 2 is stimulated, when the position is F15, the electrotactile channel 3 is stimulated, and when the position is F30, the electrotactile channel 4 is stimulated. E and F represent wrist extension and wrist flexion, respectively, and 15 and 30 represent motion angles of 15° and 30°, respectively. The stimulated channel changes with the change of the prosthesis angle.

[0223] 2) When the myoelectric prosthesis movement posture information is wrist flexion, the electrotactile stimulation is performed in the channel in a clockwise order. The larger the angle, the farther the stimulated channel is from the central axis; the vibrotactile stimulation activates channel 3 and channel 4 simultaneously.

[0224] 3) When the myoelectric prosthesis movement posture information is wrist extension, the electrotactile stimulation is performed in the channel counterclockwise in sequence, and the larger the angle, the farther the stimulated channel is from the central axis; the vibrotactile stimulation activates channel 1 and channel 2 simultaneously.

[0225] 4) When the myoelectric prosthesis motion posture information is high speed, the vibration stimulation is correspondingly set to high frequency; when the myoelectric prosthesis motion posture information is medium speed, the vibration stimulation is correspondingly set to medium frequency; when the myoelectric prosthesis motion posture information is low speed, the vibration stimulation is correspondingly set to low frequency.

[0226] Embodiment 25:

[0227] See also Figures 1 to 6 A hybrid tactile stimulation system for feeding back prosthetic wrist motion information to amputees, the system includes a main control module, a motor drive module, a tactile stimulation module, and a hybrid tactile stimulation electrode array module, which are embedded in a myoelectric prosthesis to provide sensory feedback to the user.

[0228] The hybrid tactile stimulation system is embedded in the receiving cavity inside the myoelectric prosthesis when in use, and the stimulation output part is closely connected to the user's arm, which is the core component for generating tactile stimulation.

[0229] The power consumption of the hybrid tactile stimulation system when not connected to the hybrid tactile stimulation electrode array, not connected to Bluetooth, and not driving the prosthetic movement is 178.2 mW, and the power consumption when not connected to the hybrid tactile stimulation electrode array and connected to Bluetooth is 191.4 mW, which has the advantage of low power consumption.

[0230] The size of the vibration stimulation circuit board of the vibration stimulation-control system is 69.7 mm×41.9 mm, and the size of the vibration electrode array is 112.5 mm*73 mm, which has the advantages of miniaturization and portability.

[0231] The main control module uses STM32F103RCT6 as the main control chip of the system, with multiple peripherals built in, including analog-to-digital converters, timers, interrupt controllers, digital interface integrated circuits and various communication interfaces, which can help users achieve more flexible and complex functions. It is an embedded system with the advantages of high performance, low cost, and low power consumption, which can provide control signals for this design.

[0232] The vibration stimulation part in the hybrid tactile stimulation module realizes the selection of the vibration channel through the 74LVC1G157GW multiplexer chip. When a high level is provided to the Select end of the chip, the PWM signal at the Input end will be output to the Y end, thereby reaching the gate of AO3400. Therefore, at the high level of the PWM wave, the 3.3V voltage of the drain will be given to the vibration motor connected to the source, realizing the function of controlling the motor output stimulation.

[0233] The power conversion isolation module is a module that provides power support. It is powered by an 8V rechargeable battery that comes with the prosthesis. Each circuit obtains the corresponding voltage power supply through the designed voltage conversion module: the power supply voltage of the electromyographic signal analog-to-digital conversion module, the main control module and the Bluetooth communication module is 3.3V, the power supply voltage of the electromyographic acquisition electrode and the drive module is 5V, and the vibration motor is within the rated working voltage range. 3.3V voltage is selected for power supply. The size of the electrotactile stimulation is controlled by a constant current source. Since the human body impedance size is floating, in order to ensure that the current size within the preset range can be provided, a 70V voltage needs to be provided. Therefore, the system designs multiple voltage conversion circuits, which are 8V to 12V, 12V to 70V, 12V to 5V and 5V to 3.3V.

[0234] The chip used in the 8V to 12V circuit is TPS61089RNRR, and its maximum output current of 7A can meet the power requirements of the system.

[0235] The 12V to 70V circuit adopts a DCDC switching power supply, and the circuit topology is a Boost circuit with feedback. The voltage level of this circuit is relatively high, and the system uses the MCP1650S chip, which can raise the voltage to more than 100V, and the allowed output is 5W, and the working quiescent current is 120μA, which meets the design requirements.

[0236] The 12V to 5V converter uses a high-performance Buck DCDC chip TPS563201 produced by Texas Instruments. The input voltage range of this chip is 2.95V to 17V, and the output voltage can be adjusted according to the external circuit, usually between 0.8V and 6V. This circuit sets the output voltage to 5V by setting the two sets of resistor values ​​connected to the VFB interface, and the output current can reach up to 3A.

[0237] The chip used in the 5V to 3.3V circuit is TLV70433, which is a low voltage drop linear regulator chip with low voltage drop and low quiescent current. It can be used to convert the input voltage from 3.5V to 28V down to the output voltage of 1.2V to 5.5V. The circuit using TLV70433 is very simple and easy to design, which can reduce the number of components and cost in the system.

[0238] Furthermore, the power conversion isolation module also provides an isolation function to isolate the power supply and the application circuit to improve system safety. The power isolation function realizes 12V-12V DCDC isolation through the isolation module URB2412YMD-10WR3, with an output power of up to 10W and an isolation voltage of up to 1500VDC.

[0239] The myoelectric prosthesis comprises a receiving cavity, a wrist joint motor with an encoder, an electromyographic signal analog-to-digital conversion module, and electromyographic collection electrodes.

[0240] The motor drive module realizes the movement of the myoelectric prosthesis by controlling the direction and speed of the wrist joint motor 4 with an encoder in the myoelectric prosthesis.

[0241] The main control module is electrically connected to the tactile stimulation module, and the stimulation parameters are set according to the working state of the motor: the intensity, frequency and mode of the vibration and electrical tactile stimulation are adjusted, which can be achieved by using buttons, switches or programmable electronic control systems to produce mixed tactile stimulation acting on the upper arm of the prosthesis user.

[0242] The hybrid tactile stimulation electrode array is made of a flexible circuit board, consisting of a silicon substrate, a thin film electrode and a micro vibration motor. It can fit perfectly with the user's upper arm and is safe and portable. It has a higher degree of integration and is more systematic than discrete vibration devices.

[0243] The flexible electrode array is electrically connected to the tactile stimulator via a flat cable and an FPC connector, and contacts the upper arm of the user to transmit tactile stimulation.

[0244] The vibrating electrode array uses a 2-layer flexible circuit board with a thickness of 0.12mm±0.03mm, a yellow covering film, a copper surface material, and a single size of 112.5mm*73mm, which is consistent with the arm circumference length range of an adult human upper limb.

[0245] The micro vibration motor is a rotor motor with a diameter of 10 mm, a thickness of 2.7 mm, a rated speed of 11000±2500 rpm, a rated working voltage of 3.0 V, and a rated current of 80 mA.

[0246] The micro vibration motor is driven by PWM square wave. The user can change the duty cycle of the PWM acting on the motor, thereby changing the effective voltage at both ends of the motor, and finally achieving the purpose of changing the vibration intensity of the motor. Each motor can achieve independent control of parameters.

[0247] The circuit system is as follows Figure 2 As shown. The rechargeable battery is used to power each module after voltage conversion. The prosthesis module includes a motor for controlling the movement of the prosthesis, an encoder that provides the prosthesis movement angle information, and an electromyographic signal analog-to-digital conversion module that drives the motor movement. The tactile stimulation generation module receives the electromyographic signal analog-to-digital conversion module through the Bluetooth communication module to transmit the prosthesis movement posture information and the control data transmitted by the host computer to generate a stimulation output signal.

[0248] When the four positions of wrist flexion and extension are mapped to the electrotactile sensation induced by different channels of the electrotactile electrode array, static position sense and dynamic isokinetic motion sense are established based on the timing established by the stimulation position. When the three speeds of wrist flexion and extension are mapped to the vibrotactile sensation induced by different frequencies of the vibrating electrode array, dynamic variable speed motion sense is established based on the timing established by the stimulation frequency and channel changes.

[0249] Embodiment 26:

[0250] See also Figures 1 to 6 A hybrid tactile stimulation system for providing feedback on prosthetic wrist joint movement to amputees. The system is embedded in a myoelectric prosthesis and electrically connected to the myoelectric prosthesis. It provides different modes of hybrid tactile stimulation based on the kinematic parameters of the prosthesis, helping the user to obtain sensory feedback while manipulating the prosthesis.

[0251] The system is embedded in the myoelectric prosthesis and electrically connected to the myoelectric prosthesis, providing different modes of tactile stimulation according to the kinematic parameters of the prosthesis, helping the user to obtain sensory feedback while manipulating the prosthesis.

[0252] The hybrid tactile stimulation-control system includes the following components: a main control module, a motor drive module, a vibration stimulation module, a vibration electrode array module, and a power conversion isolation module, and has the advantages of miniaturization and portability.

[0253] The hybrid tactile stimulation-control system is embedded in the internal receiving cavity of the myoelectric prosthesis when in use, and the stimulation output part is closely connected to the user's arm, which is the core component for generating tactile sensation.

[0254] The myoelectric prosthesis comprises a receiving cavity, a wrist joint motor with an encoder, an electromyographic signal analog-to-digital conversion module, and electromyographic collection electrodes.

[0255] The motor drive module realizes the movement of the myoelectric prosthesis by controlling the direction and speed of the wrist joint motor 4 with an encoder in the myoelectric prosthesis.

[0256] The main control module is electrically connected to the tactile stimulation module, and the stimulation parameters are set according to the working state of the motor: the intensity, frequency and mode of the vibration and electrical tactile stimulation are adjusted, which can be achieved by using buttons, switches or programmable electronic control systems to produce mixed tactile stimulation acting on the upper arm of the prosthesis user.

[0257] The hybrid tactile stimulation electrode array is made of a flexible circuit board, consisting of a silicon substrate, a thin film electrode and a micro vibration motor. It can fit perfectly with the user's upper arm and is safe and portable. It has a higher degree of integration and is more systematic than discrete vibration devices.

[0258] The flexible electrode array is electrically connected to the tactile stimulator via a flat cable and an FPC connector, and contacts the upper arm of the user to transmit tactile stimulation.

[0259] The vibrating electrode array uses a 2-layer flexible circuit board with a thickness of 0.12mm±0.03mm, a yellow covering film, a copper surface material, and a single size of 112.5mm*73mm, which is consistent with the arm circumference length range of an adult human upper limb.

[0260] The micro vibration motor is a rotor motor with a diameter of 10 mm, a thickness of 2.7 mm, a rated speed of 11000±2500 rpm, a rated working voltage of 3.0 V, and a rated current of 80 mA.

[0261] The micro vibration motor is driven by PWM square wave. The user can change the duty cycle of the PWM acting on the motor, thereby changing the effective voltage at both ends of the motor, and finally achieving the purpose of changing the vibration intensity of the motor. Each motor can achieve independent control of parameters.

[0262] Based on the hybrid tactile stimulation-control system for motion sensory feedback and active control of a myoelectric prosthetic wrist, a sensory feedback method for mapping myoelectric prosthetic wrist flexion and extension motion using multi-channel hybrid tactile stimulation is designed.

[0263] When the four positions of wrist flexion and extension are mapped to the electrotactile sensation induced by different channels of the electrotactile electrode array, static position sense and dynamic isokinetic motion sense are established based on the timing established by the stimulation position. When the three speeds of wrist flexion and extension are mapped to the vibrotactile sensation induced by different frequencies of the vibrating electrode array, dynamic variable speed motion sense is established based on the timing established by the stimulation frequency and channel changes.

[0264] The flexible hybrid tactile electrode array includes 4 micro vibration motors and 4 electrotactile stimulation electrodes, which are respectively recorded as vibration channels: VCH1, VCH2, VCH3, VCH4. Electrotactile stimulation channels: ECH1, ECH2, ECH3, ECH4. The vibration and electrotactile stimulation of the same channel number are at the same position of the electrode array. The two electrodes on the back of the upper arm correspond to the wrist extension direction of the prosthetic wrist, and the two electrodes on the palm side correspond to the wrist flexion direction. The larger the angle of movement, the farther the activated stimulation channel is from the central axis.

[0265] Use different modes of tactile stimulation to map the prosthetic motion posture information of the myoelectric prosthesis. When the position of the prosthetic motion posture information of the myoelectric prosthesis is E30, the channel ECH1 is stimulated, when the position is E15, the channel ECH2 is stimulated, when the position is F15, the channel ECH3 is stimulated, and when the position is F30, the channel ECH4 is stimulated. E and F represent wrist extension and wrist flexion, respectively, and 15 and 30 represent motion angles of 15° and 30°, respectively. The stimulated channel changes with the change of the prosthetic angle.

[0266] When the myoelectric prosthesis moves in the direction of wrist extension from 0° to 30°, the two channels VCH1 and VCH2 are activated. When the myoelectric prosthesis moves in the direction of wrist extension from 0° to 30°, the two channels VCH3 and VCH4 are activated.

[0267] In the mapping mode of the electrotactile stimulation channel and the isokinetic motion information of the prosthesis, the vibration stimulation duration of each channel is 0.5 seconds, the stimulation frequency is fixed in the range of [10,200 Hz], and the stimulation intensity is fixed in the range of [0,8 mA].

[0268] In the mapping mode of the vibration stimulation frequency and the prosthesis variable speed motion information, when the myoelectric prosthesis performs wrist flexion and extension, each channel adopts a continuous vibration mode, and the vibration stimulation frequency changes with the change of the motion speed. When the motion is high-speed, the vibration stimulation frequency corresponds to a high frequency of 200Hz. When the motion is medium-speed, the vibration stimulation frequency corresponds to a medium frequency of 100Hz. When the motion is low-speed, the vibration stimulation frequency corresponds to a low frequency of 50Hz.

Claims

1. A hybrid tactile stimulation system for providing amputees with feedback of prosthetic wrist motion information, characterized in that: The hybrid tactile stimulation system interacts with the myoelectric prosthesis to provide the user with sensory feedback on the wrist; The myoelectric prosthesis comprises a receiving cavity, a myoelectric acquisition electrode (1), and a wrist joint motor (4) with an encoder; The hybrid tactile stimulation system comprises an electromyographic signal analog-to-digital conversion module (2), a motor drive module (3), a main control module (5), a tactile stimulation module (6), and a multi-channel hybrid tactile stimulation electrode array module (7); The multi-channel hybrid tactile stimulation electrode array module (7) comprises n micro-vibration motors (9), n electric tactile stimulation electrodes, an FPC connector (10), and a flexible circuit board, where n is a positive integer; The micro vibration motor (9) is used to generate vibration stimulation on the upper arm of the user. The electrotactile stimulation electrode is attached to the upper arm of the user of the myoelectric prosthesis to generate electrotactile stimulation on the upper arm of the user; The FPC connector (10) connects the n micro-vibration motors and the n electric tactile stimulation electrodes to the tactile stimulation module (6) respectively through wiring, thereby realizing multi-channel output of mixed tactile stimulation; One surface of the flexible circuit board is provided with n micro-vibration motors (9) spaced apart from each other, and the other surface is provided with n electric tactile stimulation electrodes spaced apart from each other; The myoelectric acquisition electrode (1) acquires two-channel myoelectric signals of a pair of antagonistic muscles in the user's forearm; The electromyographic signal analog-to-digital conversion module (2) performs analog-to-digital conversion on the two-channel electromyographic signals to obtain corresponding digital signals, and generates prosthetic movement control instructions based on the digital signals corresponding to the two-channel electromyographic signals; The electromyographic signal analog-to-digital conversion module (2) generates a motor drive signal and sends the motor drive signal to the main control module (5); After receiving the motor drive signal, the main control module (5) enables the motor drive module (3) to control the wrist joint motor (4) with an encoder in the myoelectric prosthesis to move according to the prosthesis motion control instruction; When the myoelectric prosthesis moves, the encoder of the wrist joint motor (4) with an encoder feeds back the motor rotation angle to monitor the prosthesis movement posture information (8) in real time, and transmits the prosthesis movement posture information (8) to the main control module (5); The main control module (5) encodes the prosthetic movement posture information (8) into a tactile stimulation pattern, and controls the tactile stimulation module (6) to output a tactile stimulation sequence on the multi-channel mixed tactile stimulation electrode array module (7).

2. A hybrid tactile stimulation system for providing amputees with feedback of prosthetic wrist motion information according to claim 1, characterized in that: The system also includes a power conversion isolation module; The power conversion isolation module supplies power to the electromyographic acquisition electrode (1), the electromyographic signal analog-to-digital conversion module (2), the motor drive module (3), the wrist joint motor with encoder (4), the main control module (5), the tactile stimulation module (6), and the multi-channel mixed tactile stimulation electrode array module (7); The power conversion isolation module isolates the power supply of the electromyographic acquisition electrode (1), the electromyographic signal analog-to-digital conversion module (2), and the power supply of the motor drive module (3), the wrist joint motor with encoder (4), the main control module (5), the tactile stimulation module (6), and the multi-channel mixed tactile stimulation electrode array module (7).

3. The hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees according to claim 1, characterized in that: The prosthetic movement control instructions include the direction and rotation speed of the myoelectric prosthetic wrist joint.

4. The hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees according to claim 1, characterized in that: The movement types of the myoelectric prosthesis include wrist flexion and wrist extension.

5. The hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees according to claim 1, characterized in that: The position of the micro vibration motor (9) on the flexible circuit board corresponds to the position of the electric tactile stimulation electrode.

6. The hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees according to claim 1, characterized in that: The voltage amplitude range received by the micro vibration motor (9) is [0, 3.3 V].

7. A hybrid tactile stimulation system for providing amputees with feedback of prosthetic wrist motion information according to claim 1, characterized in that: The stimulation intensity range of the electrotactile stimulation electrode is [0,8mA].

8. The hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees according to claim 1, characterized in that: The tactile stimulation module (6) outputs a tactile stimulation sequence with an amplitude range of [b, 3.3 V] and a modulation frequency range of [20 Hz, 200 Hz], and an electrotactile stimulation sequence with an amplitude range of [c, d] and a modulation frequency range of [0, 200 Hz], wherein b is a vibration sensation threshold, c is an electrotactile sensation threshold, and d is an electrotactile pain threshold.

9. The hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees according to claim 1, characterized in that: The parameters of the vibration stimulation include vibration frequency, vibration duration, vibration intensity, and vibration interval duration.

10. The hybrid tactile stimulation system for providing feedback of prosthetic wrist motion information to amputees according to claim 1, characterized in that: The stimulation waveform of the electrotactile stimulation includes a biphasic rectangular pulse; The parameters of the electrotactile stimulation include stimulation frequency, stimulation amplitude, stimulation pulse width, and stimulation delay.

Images