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CN114732576A - Multi-channel electrical stimulation system and stimulation method - Google Patents

Multi-channel electrical stimulation system and stimulation method Download PDF

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Publication number
CN114732576A
CN114732576A CN202210294726.5A CN202210294726A CN114732576A CN 114732576 A CN114732576 A CN 114732576A CN 202210294726 A CN202210294726 A CN 202210294726A CN 114732576 A CN114732576 A CN 114732576A
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stimulation
module
channel
waveform
frequency
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高文锐
尹奎英
刘川
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CETC 14 Research Institute
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    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50—Prostheses not implantable in the body
    • A61F2/68—Operating or control means
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/36014—External stimulators, e.g. with patch electrodes
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00—Electrotherapy; Circuits therefor
    • A61N1/18—Applying electric currents by contact electrodes
    • A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/36014—External stimulators, e.g. with patch electrodes
    • A61N1/3603—Control systems
    • A61N1/36034—Control systems specified by the stimulation parameters
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50—Prostheses not implantable in the body
    • A61F2002/5058—Prostheses not implantable in the body having means for restoring the perception of senses
    • A61F2002/5059—Prostheses not implantable in the body having means for restoring the perception of senses the feeling of position
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50—Prostheses not implantable in the body
    • A61F2002/5058—Prostheses not implantable in the body having means for restoring the perception of senses
    • A61F2002/5061—Prostheses not implantable in the body having means for restoring the perception of senses the sense of touch
    • A—HUMAN NECESSITIES
    • A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61F—FILTERS IMPLANTABLE INTO BLOOD VESSELS; PROSTHESES; DEVICES PROVIDING PATENCY TO, OR PREVENTING COLLAPSING OF, TUBULAR STRUCTURES OF THE BODY, e.g. STENTS; ORTHOPAEDIC, NURSING OR CONTRACEPTIVE DEVICES; FOMENTATION; TREATMENT OR PROTECTION OF EYES OR EARS; BANDAGES, DRESSINGS OR ABSORBENT PADS; FIRST-AID KITS
    • A61F2/00—Filters implantable into blood vessels; Prostheses, i.e. artificial substitutes or replacements for parts of the body; Appliances for connecting them with the body; Devices providing patency to, or preventing collapsing of, tubular structures of the body, e.g. stents
    • A61F2/50—Prostheses not implantable in the body
    • A61F2/68—Operating or control means
    • A61F2002/6827—Feedback system for providing user sensation, e.g. by force, contact or position
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02D—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN INFORMATION AND COMMUNICATION TECHNOLOGIES [ICT], I.E. INFORMATION AND COMMUNICATION TECHNOLOGIES AIMING AT THE REDUCTION OF THEIR OWN ENERGY USE
    • Y02D30/00—Reducing energy consumption in communication networks
    • Y02D30/70—Reducing energy consumption in communication networks in wireless communication networks

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  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Animal Behavior & Ethology (AREA)
  • General Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
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  • Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
  • Biophysics (AREA)
  • Radiology & Medical Imaging (AREA)
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  • Oral & Maxillofacial Surgery (AREA)
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  • Electrotherapy Devices (AREA)

Abstract

The existing commercial prosthetic hand system has developed more beautiful appearance and enough driving freedom degrees, which can meet the daily life of amputees, but the artificial hand device cannot be incorporated into the proprioceptive mapping due to the general lack of effective sensory feedback function. On one hand, the disabled can easily generate the feeling of fatigue control and psychological conflict emotion in the using process, so that the using frequency of the dexterous hand equipment is greatly reduced or the use of the dexterous hand equipment is abandoned; on the other hand, the lack of multi-sensory feedback such as pressure sense and position sense also causes the patient not to perform fine actions such as pinching, grasping and touching in real time, and becomes a critical technical link which needs to be solved urgently in the field of current artificial hand research. The invention provides a multi-channel electrical stimulation system and a stimulation method for dexterous hand touch sense and position sense feedback, which can output portable electrical stimulation equipment with high real-time performance, wide frequency and multiple channels, wherein a multi-channel gating circuit is specially designed for expanding the number of stimulation channels of a constant voltage source, and the contradiction between overlarge circuit size and the requirement on portability of a prosthetic hand system is solved; meanwhile, a current monitoring circuit is designed in a matching mode, and the current gathering phenomenon caused by skin impedance change or electrode falling is prevented.

Description

Multi-channel electrical stimulation system and stimulation method
Technical Field
The invention belongs to the field of artificial limb tactile feedback acquisition, and particularly relates to a multi-channel electrical stimulation system and an information feedback method suitable for dexterous hand touch sense and position sense feedback.
Background
The existing commercial prosthetic hand system has developed more beautiful appearance and enough driving freedom degrees, which can meet the daily life of amputees, but the artificial hand device cannot be incorporated into the proprioceptive mapping due to the general lack of effective sensory feedback function. On one hand, the disabled can easily generate the feeling of fatigue control and psychological conflict emotion in the using process, so that the using frequency of the dexterous hand equipment is greatly reduced or the use of the dexterous hand equipment is abandoned; on the other hand, the lack of multi-sensory feedback such as pressure sense and position sense also causes the patient not to perform fine actions such as pinching, grasping and touching in real time, and becomes a critical technical link which needs to be solved urgently in the field of current artificial hand research.
The average thickness of the skin tissue of the forearm of a human body is 0.2mm, and the forearm skin tissue is mainly divided into an epidermal layer and a dermal layer, wherein free nerve endings are positioned on the epidermal layer and mainly feel temperature sensation, light touch sensation (smaller stress) and pain stimulus; the Meise sodium corpuscle and the small body of the ring layer are positioned in the dermis layer of the skin, the former can sense fine touch (texture sense), and the latter can receive stronger stress, pressure sense and vibration sense stimulation; the finger position sense determines the finger state mainly by judging Ia fiber information in a plurality of muscle spindles. In view of the great difference between the formation mechanism of various proprioception and the electric signal conduction mode, the feedback of the perception information of the current artificial hand system is mainly realized by a sense substitution mode, namely, the patient is worn to finish sense transmission by substituting the information such as the electric stimulation frequency, the amplitude intensity, the on-off state and the like received by a skin receptor for position sense, pressure sense and motion mode information.
Through search and discovery, there are some patents issued on the artificial hand system for tactile feedback and stimulator, such as: the patent of invention with publication number CN104606779A discloses a multichannel constant current source stimulation circuit, which realizes multichannel stimulation feedback to the skin surface of a human body, but does not describe a specific expansion method for realizing multichannel stimulation feedback by an I/O port of an MCU, and cannot realize waveform stimulation by expanding more than ten independent channels through a limited I/O port in cooperation with a digital-to-analog conversion circuit and a power amplification module alone.
The invention patent with the publication number of CN110946683B discloses a multichannel low-frequency stimulation method and system, which are used for an electric stimulation method and system for feeding back the pressure and the joint angle of a fake finger tip.
The existing electrical stimulator mainly aims at constructing electrical stimulation hardware equipment and a matched stimulation method of the electrical stimulation hardware equipment and a human body surface skin electrode, is mostly suitable for the feedback condition with a single channel or less channel demand, does not clearly describe a circuit expansion method and a corresponding stimulation method when the number of stimulation channels is large, and is difficult to meet the requirements of real-time performance, accuracy and diversity of electrical stimulation feedback of a prosthetic hand system.
Disclosure of Invention
In order to solve the defects in the prior art, the invention provides a multi-channel electrical stimulation system for dexterous hand touch sense and position sense feedback, which can output high-real-time, wide-frequency and multi-channel portable electrical stimulation equipment.A multi-channel gating circuit is specially designed for expanding the number of stimulation channels of a constant voltage source and solving the contradiction between the overlarge circuit size and the portability requirement of a prosthetic hand system; meanwhile, a current monitoring circuit is designed in a matching mode, and the current gathering phenomenon caused by skin impedance change or electrode falling is prevented. Furthermore, the invention provides a stimulation method capable of feeding back multi-perception information such as the position sense, the pressure sense, the gripping state and the like of the dexterous hand, and the multi-mode stimulation effect of skin tactile nerves is achieved by utilizing the multi-channel time-space dynamic gating and the change of stimulation frequency, so that the requirement of a user for perceiving the state of the artificial hand in real time under the condition of no visual assistance is met. Voltage amplitude range of output pulse of final electrostimulator: 60V to 60V, and the precision is 0.12V; the pulse width range of the output pulse is 10 mus-1 ms, and the precision is 1 mus; the frequency adjusting range is 0-10 kHz, and the precision is 1 Hz; the start-up delay time for each channel of electrical stimulation was 10 ms.
The system specifically comprises a power supply module, a main control chip module, a signal generation module, a proportional amplification module, a precision sampling module, a current detection module, a Bluetooth communication module, a multi-channel gating module, an LCD driving and key module and an electrode interface array; wherein, the power module converts the battery voltage into a stabilized voltage power supply to provide power supply for other modules, the main control chip module controls each module through a logic control signal, the artificial hand device and the touch sensing device are connected and communicated with the main control chip module through a Bluetooth communication module or a UART serial port, the signal generation module is connected with the main control chip module through an SPI interface to generate a multi-channel stimulation waveform with independent frequency and voltage intensity, the signal generation module sends the stimulation waveform to a proportion amplification module to amplify and promote the stimulation waveform, the stimulation waveform is output to a current detection module and a multi-channel gating module after passing through a precise sampling resistor, the number of the electrical stimulation channels is further expanded by the multi-channel gating module, the signal is sent to an electrode interface array so as to be output to an external multi-channel electrical stimulation electrode array, and after intermediate frequency signals of the multi-channel stimulation current are filtered by the current detection module, and the stimulation current is fed back to the main control chip module through the ADC interface, so that the stimulation current of each channel is regulated and controlled in a closed loop mode.
Furthermore, the main control chip module is an STM32F407ZGT6 model chip, and is connected with the artificial hand device and the touch sensing device to acquire position sense and pressure sense information in real time, so as to adjust the stimulation gating mode, the carrier frequency and the stimulation intensity.
Furthermore, the signal generation module adopts an AD9959 chip, generates a multichannel sinusoidal signal by direct digital frequency synthesis, the modulation frequency can reach 500MHz at most, and the amplitude range of the voltage waveform is 1.8V +/-0.5V.
Furthermore, each channel waveform has independent frequency, phase and amplitude modulation capability, and the main control chip module can update the storage conversion word, the phase offset word and the amplitude control proportion in real time through the I/O parallel port.
Furthermore, the proportion amplification module adopts a differential amplification circuit form to condition the waveform, the operational amplifier chip adopts PA78DK to amplify the stimulation voltage amplitude to +/-60V, an intermediate frequency carrier signal is formed, and the penetrability and sensitivity of the stimulation signal to human skin tissues are ensured.
Furthermore, the multichannel gating module performs time-sharing multiplexing on the electrical stimulation signals in a switch gating mode, an MAX14803 chip is used as the gating switch module, and the intermediate-frequency carrier signals output by the proportional amplification module are evenly distributed into 3-5 channels to form a TENS stimulation waveform with a low-frequency duty ratio; the main control chip module directly controls the dynamic switching state of the channel according to the finger joint position and pressure information, the low-frequency modulation period of the multiplexing channel is controlled to be 50ms, the duty ratio of each channel is set to be 0.2, and a tester can still receive continuous feedback perception in a single stimulation channel.
Furthermore, the current detection module comprises a high-end sampling circuit and a voltage detection circuit, the current parameters are monitored in real time, the voltage detection circuit firstly collects the voltage value of a precision sampling resistor connected in series on a channel through a differential operational amplifier, and adds bias voltage to the collected voltage, so that the sampling voltage is obtained; based on the sinusoidal carrier signal of high-end sampling circuit output waveform for low frequency square wave envelope.
Based on a stimulation method of a multi-channel electrical stimulation system suitable for dexterous hand multi-perception feedback, the coding feedback of the position sense, the pressure sense and the gripping state of a prosthetic hand is realized by dynamically gating stimulation channels at different positions, a user can realize real-time perception of the state of the prosthetic hand without visual assistance, and the specific control flow is as follows:
1) after the system is powered on, firstly enabling a clock, initializing each module, and keeping a stimulation mode and a stimulation waveform with original parameters;
2) the control program polls whether the serial port receives joint movement information or fingertip pressure information, determines a stimulation gating mode of electrical stimulation, and stores the sensing data in a direct memory access mode;
3) according to the selected stimulation mode and the state information of the artificial hand, the gating states of channels at different spatial positions are dynamically adjusted, the amplitude, the frequency and the pulse parameters of the stimulation waveform are respectively updated, the duty ratio of the output waveform is controlled by a timer, and the joint feedback of multiple sensing information is provided;
4) through the current detection module, the stimulation current value of each channel is fed back to the main control chip module through the analog-to-digital converter for reference, so that the stability and the safety of stimulation are ensured.
The invention has the beneficial effects that:
1. the invention provides a method and a system for generating multi-channel dynamic stimulation feedback by time-sharing multiplexing of an I/O port control waveform generator; and a current detection circuit is configured for the constant voltage source stimulation equipment, so that the condition of violent change of stimulation current caused by skin impedance change and lead falling-off phenomenon is prevented.
2. The invention provides a multichannel stimulation method which is richer in carried information content and easier to perceive by a human body, and the method can be used for finishing the transmission of information such as the finger position, the interphalangeal pressure, the motion direction and the like of a prosthetic hand system to peripheral nerves of a user by dynamically adjusting parameters such as the on-off state, the pulse width, the cluster frequency and the like of a TENS waveform in real time, and can be used for finely controlling the prosthetic hand system in the absence of visual feedback.
Drawings
Fig. 1 is a schematic diagram of the composition of a multi-channel electrical stimulation driving feedback system of a prosthetic hand system.
FIG. 2 is a schematic diagram of a principle of a differential amplifying electrical module and a simulation result.
Fig. 3 is a circuit schematic diagram of time-multiplexed stimulation waveforms by gating switches.
Fig. 4 is a circuit diagram of a current detection module of a stimulus source.
Fig. 5 is a schematic diagram of a stimulation gating mode of a motion feedback mode and a pressure feedback mode, and a multichannel time-division multiplexing stimulation waveform.
Fig. 6 is a control flow diagram of the multi-channel electrical stimulation system.
Detailed Description
The following description of the embodiments of the present invention is provided in order to better understand the present invention for those skilled in the art with reference to the accompanying drawings. It is to be noted that the following description is only for explaining the present invention and is not intended to limit the present invention.
A multi-channel electrical stimulation system suitable for dexterous hand multi-perception feedback is mainly composed of a power supply module, a main control chip module, a signal generation module, a proportion amplification module, a precise sampling module, a current detection module, a Bluetooth communication module, a multi-channel gating module and an LCD driving and key module, as shown in figure 1. The power supply module converts the voltage of the portable battery into 1.8V, 3.3V, +/-15V and + -60V stabilized power supplies respectively to provide power supply for other functional modules; the main control chip module provides logic control signals for each functional module, wherein the artificial hand device and the environment sensing device are connected and communicated with the main control chip module through Bluetooth devices or UART serial devices. The signal generation module is connected with the main control chip module through an SPI interface to generate a multi-channel stimulation waveform with independent frequency and voltage intensity; on the other hand, the signal generation module is connected with the proportional amplification module, the maximum amplitude of the stimulation waveform is increased to +/-60V, and the number of the electrical stimulation channels is further expanded through the multichannel gating circuit. After the stimulating current of each channel passes through the current detection module to filter the intermediate frequency signals of 1 kHz-4 kHz, the envelope detection voltage is fed back to the main control chip module through the 12-bit analog-to-digital conversion interface, so that the closed-loop regulation and control are carried out on the stimulating current of each channel, and the programmable stimulation system with the functions of real-time updating of the stimulating pulse width, the stimulating frequency and dynamic gating is realized.
The main control chip module selects STM32F407ZGT6 chips with rich peripheral functions and enough General Purpose Interfaces (GPIO), the working main frequency can reach 168MHz, and the main control chip module can call functional modules such as general timers (12), PWM synchronous timers (2), 24-bit ADCs (3), 12-bit DACs (2), UART interfaces, SPI interfaces and the like. The main control chip is connected with the artificial hand system through a UART serial port, and acquires position sense and pressure sense information in real time, so as to adjust parameters such as stimulation gating mode, carrier frequency and stimulation intensity. The signal generation module adopts an AD9959 chip, and utilizes Direct Digital Synthesis (DDS) technology to generate 4-channel sinusoidal signals, the modulation frequency can reach 500MHz at most, and the voltage waveform amplitude range is 1.8V +/-0.5V. Each channel has independent frequency, phase and amplitude modulation capability, the main control chip module can update the storage conversion word FTW, the phase offset word POW and the amplitude control proportional word K in real time through the I/O parallel port, and a calculation formula can be expressed as follows:
Figure BDA0003561454990000051
in the formula (f)sIs the system clock frequency, foutTo output the waveform frequency, A0Is the full amplitude range, phi is the offset phase output of the output waveform, and A is the output waveform amplitude.
As shown in fig. 2, the proportional amplification module performs signal conditioning on the digital synthesized waveform in the form of a differential amplification circuit, amplifies the amplitude of the stimulation voltage to +/-60V, forms an intermediate frequency carrier signal, and ensures the penetrability and sensitivity of the stimulation signal to human skin tissues; the high-voltage operational amplifier chip of the proportional method module needs to adopt PA78DK, and the proportional amplification relation of the built circuit is shown as a formula (2):
Figure BDA0003561454990000052
wherein, let the configuration resistance R1＝R2＝500Ω，R3＝R4And (5) amplifying the input intermediate frequency signal by 120 times amplitude value at 60k omega.
According to the earlier research result, when the TENS modulation waveform frequency reaches 16 Hz-20 Hz, a tester begins to difficultly distinguish the discrete on-off state of a stimulation signal and confuses the discrete on-off state into continuous waveform electrical stimulation. The multichannel gating module performs time division multiplexing on the electrical stimulation signals in a switch gating mode, and evenly distributes the intermediate frequency carrier output by the proportion amplification module to 3-5 channels to form a TENS stimulation waveform with a low-frequency duty ratio, as shown in FIG. 3. Specifically, the MAX14803 chip is adopted as the gating switch module, the main control chip module directly controls the dynamic switching state of the channel according to the finger joint position and pressure information, the low-frequency modulation period of the multiplexing channel is controlled to be 50ms, the duty ratio of each channel is set to be 0.2, so that a tester can still receive continuous feedback perception in a single stimulation channel, and the contradiction between the continuous stimulation perception function of multiple channels and the complex and huge stimulation circuit structure is realized.
The electrical stimulation device adopts the analog constant voltage source to ensure the rapidity of stimulation, and takes into account that the stimulation electrode can cause the drastic change of skin impedance due to the phenomena of installation looseness, falling off and the like to cause the increase of local current density and the tissue burning of the stimulation electrode. The current detection module firstly collects the voltage value of a precise sampling resistor connected in series on a stimulation path through a differential operational amplifier, and the sampling resistor is close to a stimulation power supply end so as to avoid low-level noise interference; in addition, in order to avoid amplitude distortion of a subsequent detection circuit, a bias voltage is added to the collected stimulation voltage, and finally obtained sampling voltage can be expressed as:
VOUT＝RS+ILOAD+20·REFA-19·REFB (3)
considering that the output waveform of the high-end sampling circuit is a low-frequency square wave (f)MLess than or equal to 20Hz) envelope sine carrier signal (f)OUT2kHz to 4 kHz). As shown in FIG. 4, the time constant of the low-pass filter satisfies R1C1<<1/fMAnd R1C1>>1/fOUTThereby completing the stimulation signal demodulation and envelope waveform detection.
The main control chip module is provided with a 12-bit high-speed analog-to-digital converter, and can acquire the stimulation amplitude in real time to calculate the current intensity, so that stable stimulation of proprioception is realized.
In addition to the multi-channel voltage stimulation device, the invention provides a multi-sensory feedback method of space-time dynamic stimulation by matching with an electrical stimulator and a multi-channel electrode, realizes coding feedback of the position sense, the pressure sense and the gripping state of the artificial hand by dynamically gating stimulation channels at different positions, and achieves the effect of real-time perception of the state of the artificial hand by a user without visual assistance. As shown in fig. 5, the stimulation electrode is a 3x5 multi-channel electrode manufactured by FPC technology, and the electrical stimulation controller divides the gated stimulation mode into two modes of motion feedback and pressure feedback according to the motion state of the artificial hand:
1) when the fingers of the artificial hand start to move but do not receive pressure signals, the electric stimulator is in a motion feedback mode, and the device represents the motion state of the gripped/opened joints of the artificial hand in a clockwise/anticlockwise sequential stimulation mode by gating corner channels at the outermost side of the stimulation electrodes;
2) when the pressure information is sensed by the fake finger tip, the electric stimulator is in a pressure feedback state, and each column of electrodes corresponds to the position and the pressure state of the finger. The controller firstly determines the gating state of each row of electrodes according to the bending angle of each finger, and the gating conditions are divided into three-gear gating conditions by taking 30 degrees, 60 degrees and 90 degrees as channel gating judgment thresholds so as to achieve the graded feedback of the bending angle; meanwhile, the duty ratios of the modulation waveforms are respectively set to be 0.15, 0.20, 0.25 and 0.30 fourth gears according to the finger pressure, and the hierarchical feedback of the pressure information is realized.
The control flow of the multichannel electrical stimulation is shown in fig. 6, and the specific control flow is as follows:
1) after the system is powered on, the clock is enabled firstly, each functional module is initialized, and the stimulation mode and the stimulation waveform with the original parameters are kept (the waveform is not output for the first time).
2) And the control program polls whether the serial port receives the joint movement information or the fingertip pressure information, determines a stimulation gating mode of the electric stimulation, and stores the sensing data in a Direct Memory Access (DMA) mode.
3) According to the selected stimulation mode and the state information of the artificial hand, the gating states of different spatial position channels are dynamically adjusted, the stimulation waveform parameters such as amplitude, frequency and pulse are respectively updated, the duty ratio of the output waveform is controlled through a timer, and the joint feedback of the multi-perception information is provided.
4) Through the current detection module, the stimulation current value of each channel is fed back to the main control chip module through the analog-to-digital converter for reference, so that the effects of stimulation stability and safety are achieved.
The present invention has been described in detail with reference to the foregoing description, but it should be understood that the detailed description is given for the purpose of illustrating the method and the core concept of the invention, and it is apparent that the invention is not limited thereto, since various changes may be made therein by those skilled in the art without departing from the spirit and scope of the invention as defined and defined in the appended claims.

Claims (8)

1. The utility model provides a multichannel electrical stimulation system suitable for multiple perception feedback of dexterous hand which characterized in that: the system comprises a power supply module, a main control chip module, a signal generation module, a proportional amplification module, a precise sampling module, a current detection module, a Bluetooth communication module, a multi-channel gating module, an LCD driving and key module and an electrode interface array; wherein, the power module converts the battery voltage into a stabilized voltage power supply to provide power supply for other modules, the main control chip module controls each module through a logic control signal, the artificial hand device and the touch sensing device are connected and communicated with the main control chip module through a Bluetooth communication module or a UART serial port, the signal generation module is connected with the main control chip module through an SPI interface to generate a multi-channel stimulation waveform with independent frequency and voltage intensity, the signal generation module sends the stimulation waveform to a proportion amplification module to amplify and promote the stimulation waveform, the stimulation waveform is output to a current detection module and a multi-channel gating module after passing through a precise sampling resistor, the number of the electrical stimulation channels is further expanded by the multi-channel gating module, the signal is sent to an electrode interface array so as to be output to an external multi-channel electrical stimulation electrode array, and after intermediate frequency signals of the multi-channel stimulation current are filtered by the current detection module, and the stimulation current is fed back to the main control chip module through the ADC interface, so that the stimulation current of each channel is regulated and controlled in a closed loop mode.
2. A multi-channel electrical stimulation system suitable for multi-sensory feedback to a dexterous hand as claimed in claim 1, wherein: the main control chip module is an STM32F407ZGT6 model chip, is connected with the artificial hand device and the touch sensing device, acquires position sense and pressure sense information in real time, and further adjusts the stimulation gating mode, the carrier frequency and the stimulation intensity.
3. A multi-channel electrical stimulation system suitable for multi-sensory feedback to a dexterous hand as claimed in claim 1, wherein: the signal generation module adopts an AD9959 chip, generates a multichannel sinusoidal signal by direct digital frequency synthesis, the modulation frequency can reach 500MHz at most, and the amplitude range of the voltage waveform is 1.8V +/-0.5V.
4. A multi-channel electrical stimulation system suitable for multi-sensory feedback to a dexterous hand as claimed in claim 1, wherein: each channel waveform has independent frequency, phase and amplitude modulation capability, and the main control chip module can update the storage conversion word, the phase offset word and the amplitude control proportion in real time through the I/O parallel port.
5. A multi-channel electrical stimulation system suitable for multi-sensory feedback to a dexterous hand as claimed in claim 1, wherein: the proportion amplification module adopts a differential amplification circuit form to condition the waveform, the operational amplifier chip adopts PA78DK to amplify the stimulation voltage amplitude to +/-60V, an intermediate frequency carrier signal is formed, and the penetrability and sensitivity of the stimulation signal to human skin tissues are ensured.
6. The multi-channel electrical stimulation system for multi-sensory feedback of a dexterous hand of claim 1, wherein: the multichannel gating module performs time-sharing multiplexing on the electrical stimulation signals in a switch gating mode, an MAX14803 chip is used as the gating switch module, and the intermediate-frequency carrier signals output by the proportion amplification module are evenly distributed into 3-5 channels to form a TENS stimulation waveform with a low-frequency duty ratio; the main control chip module directly controls the dynamic switching state of the channel according to the finger joint position and pressure information, the low-frequency modulation period of the multiplexing channel is controlled to be 50ms, the duty ratio of each channel is set to be 0.2, and a tester can still receive continuous feedback perception in a single stimulation channel.
7. A multi-channel electrical stimulation system suitable for multi-sensory feedback to a dexterous hand as claimed in claim 1, wherein: the current detection module comprises a high-end sampling circuit and a voltage detection circuit, current parameters are monitored in real time, the voltage detection circuit firstly collects the voltage value of a precision sampling resistor connected in series on a channel through a differential operational amplifier, bias voltage is added to the collected voltage, and therefore sampling voltage is obtained, and then a sine carrier signal with a low-frequency square wave envelope waveform is output through the high-end sampling circuit.
8. The stimulation method of the multichannel electrical stimulation system suitable for dexterous hand multi-perception feedback, which is based on the claim 1, is characterized in that: the coded feedback of the position sense, the pressure sense and the gripping state of the artificial hand is realized by dynamically gating stimulation channels at different positions, so that a user can sense the state of the artificial hand in real time under the condition of no visual assistance, and the specific control flow is as follows:
1) after the system is powered on, firstly enabling a clock, initializing each module, and keeping a stimulation mode and a stimulation waveform with original parameters;
2) the control program polls whether the serial port receives joint movement information or fingertip pressure information, determines a stimulation gating mode of electrical stimulation, and stores the sensing data in a direct memory access mode;
3) according to the selected stimulation mode and the state information of the artificial hand, the gating states of different spatial position channels are dynamically adjusted, the amplitude, the frequency and the pulse parameters of the stimulation waveform are respectively updated at the same time, the duty ratio of the output waveform is controlled through a timer, and the joint feedback of multiple perception information is provided;
4) through the current detection module, the stimulation current value of each channel is fed back to the main control chip module through the analog-to-digital converter for reference, so that the stability and the safety of stimulation are ensured.
CN202210294726.5A 2022-03-23 2022-03-23 Multi-channel electrical stimulation system and stimulation method Pending CN114732576A (en)

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CN115633420A (en) * 2022-09-30 2023-01-20 苏州艾微视图像科技有限公司 Multi-channel adjustable light source control system and control method
CN116440420A (en) * 2023-05-30 2023-07-18 河南翔宇医疗设备股份有限公司 Magnetic field intensity linear control method applied to laser magnetic field physiotherapy instrument
CN116549842A (en) * 2023-07-10 2023-08-08 大悦创新（苏州）医疗科技股份有限公司 Multichannel bidirectional constant-current electric stimulation system, method and electrotherapy equipment
CN117180612A (en) * 2023-11-06 2023-12-08 苏州景昱医疗器械有限公司 Implantable electrode, stimulator, control method thereof, and storage medium

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN115633420A (en) * 2022-09-30 2023-01-20 苏州艾微视图像科技有限公司 Multi-channel adjustable light source control system and control method
CN115633420B (en) * 2022-09-30 2023-09-29 苏州艾微视图像科技有限公司 Multichannel adjustable light source control system and control method
CN116440420A (en) * 2023-05-30 2023-07-18 河南翔宇医疗设备股份有限公司 Magnetic field intensity linear control method applied to laser magnetic field physiotherapy instrument
CN116549842A (en) * 2023-07-10 2023-08-08 大悦创新（苏州）医疗科技股份有限公司 Multichannel bidirectional constant-current electric stimulation system, method and electrotherapy equipment
CN116549842B (en) * 2023-07-10 2023-09-15 大悦创新（苏州）医疗科技股份有限公司 Multichannel bidirectional constant-current electric stimulation system, method and electrotherapy equipment
CN117180612A (en) * 2023-11-06 2023-12-08 苏州景昱医疗器械有限公司 Implantable electrode, stimulator, control method thereof, and storage medium
CN117180612B (en) * 2023-11-06 2024-01-30 景昱医疗科技（苏州）股份有限公司 Implantable electrode, stimulator, control method thereof, and storage medium

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