阅读说明：本技术 一种柔性驱动的手功能康复机器人控制系统及控制方法 (Flexibly-driven hand function rehabilitation robot control system and control method ) 是由 李传江 王明月 刘洪梅 曹晶晶 朱燕飞 于 2020-07-03 设计创作，主要内容包括：本发明涉及一种柔性驱动的手功能康复机器人控制系统,包括相互之间通过电信号连接的康复手套(1)、鲍登线传动机构(2)、电控单元(3)、肌电人机接口单元(4)、脑电人机接口单元(5)、康复训练软件(6)和电机驱动单元(7),实现手指的运动位置控制和抓握力柔顺控制,各部件相互配合完成设定的被动训练和交互训练任务,具有远程指导在线训练和离线训练功能。与现有技术相比,本发明具有精度高、响应快、良好的鲁棒性等优点。(The invention relates to a flexibly-driven hand function rehabilitation robot control system which comprises rehabilitation gloves (1), a Bowden cable transmission mechanism (2), an electric control unit (3), a myoelectricity man-machine interface unit (4), an electroencephalogram man-machine interface unit (5), rehabilitation training software (6) and a motor driving unit (7) which are connected with one another through electric signals, so that the control of the motion position of fingers and the flexible control of the gripping force are realized, all parts are matched with one another to complete set passive training and interactive training tasks, and the flexibly-driven hand function rehabilitation robot control system has the functions of remotely guiding on-line training and off-line training. Compared with the prior art, the method has the advantages of high precision, quick response, good robustness and the like.)

1. A flexibly-driven hand function rehabilitation robot control system is characterized by comprising a rehabilitation glove (1), a Bowden cable transmission mechanism (2), an electric control unit (3), a myoelectricity man-machine interface unit (4), an electroencephalogram man-machine interface unit (5), rehabilitation training software (6) and a motor driving unit (7) which are mutually connected through electric signals, so that the motion position control and the gripping force flexible control of fingers are realized, all the components are mutually matched to finish set passive training and interactive training tasks, and the flexibly-driven hand function rehabilitation robot control system has the functions of remotely guiding on-line training and off-line training;

the rehabilitation glove (1) consists of a glove body, a fingertip fixing module and a palm back fixing module, wherein the fingertip fixing module is used for fixing a Bowden cable of the Bowden cable transmission mechanism (2), and the palm back fixing module is used for fixing a Bowden cable tube of the Bowden cable transmission mechanism (2);

the Bowden cable transmission mechanism (2) consists of a disc transmission mechanism and a Bowden cable traction device, one end of the Bowden cable traction device is fixed on a direct-current speed reduction motor of the motor driving unit (7), and the other end of the Bowden cable traction device is fixed on the rehabilitation glove (1). The direct-current speed reducing motor is a direct-current speed reducing motor with an encoder, the position and the speed of the motor are fed back, double closed-loop control of the speed and the position is formed, and the buckling and the extension of fingers are driven;

the electric control unit (3) consists of an STM32 main control unit and a sensor unit, the sensor unit is arranged on a rehabilitation glove (1) and comprises an RFP bending sensor and an RFP force sensor, the RFP bending sensor collects the bending angle of fingers in real time to obtain the movement position information of the fingers, the movement position information of the fingers is converted into a motor driving instruction through a position controller to complete the position control of the fingers, the RFP force sensor collects the gripping force information of the fingers in real time and converts the gripping force information of the fingers into the motor driving instruction through a force controller to complete the flexible control of the gripping force of the fingers, the electric control unit (3) uploads the processed sensor data to rehabilitation training software (6), and the rehabilitation training software (6) uploads the data to a server;

the rehabilitation training software (6) sends a corresponding command to the electric control unit (3), the electric control unit (3) analyzes the received command into a corresponding training parameter, the position controller or the force controller is selected to convert the position or the force into a driver control command, and the motor driving unit (7) is controlled to drive the Bowden cable transmission mechanism (2) to transmit traction force generated by the motor to the hand of a patient through the rehabilitation glove (1).

2. The flexibly-driven control system of the robot for hand function rehabilitation according to claim 1, wherein the electromyographic human-computer interface unit (4) is connected with the rehabilitation training software (6) in a Bluetooth manner, is provided with an electromyographic arm ring, collects surface electromyographic signals on the arm of the patient through the electromyographic arm ring, amplifies and adjusts the surface electromyographic signals, inputs the surface electromyographic signals to an STM32 processor for AD sampling, utilizes a digital filter to carry out band-pass filtering on the two collected surface electromyographic signals, respectively extracts four time domain and frequency domain characteristic values to form an eight-dimensional characteristic matrix, guides the eight-dimensional characteristic matrix into a BP classification model to obtain corresponding weight and threshold coefficient, finally, the STM32 main control unit carries out corresponding operation on the weight and the threshold to obtain a corresponding action on-line recognition result and outputs a control signal in real time, and sending the output control signal to a rehabilitation training software (6) to control the rehabilitation robot body to execute corresponding actions.

3. The flexibly driven control system for the hand function rehabilitation robot according to claim 1, wherein the control system is provided with three training modes, which are respectively a passive training mode, an interactive training mode and a remote rehabilitation training mode according to the hemiplegia degree of the affected limb of the patient, and the passive training mode is used for driving the finger of the patient to perform corresponding actions; the interactive training mode is divided into a myoelectric interactive system and an electroencephalogram interactive system, and rehabilitation training is completed by using the physiological signal of the patient, so that active training is completed; the remote rehabilitation training mode refers to the fact that a patient end is in contact with a remote server end where a rehabilitation teacher is located through a network and comprises an online mode and an offline mode, the online mode specifically refers to the fact that video, voice and characters are communicated, the training condition of the patient is fed back in real time, and the offline mode refers to the fact that historical data corresponding to the patient stored in a server are displayed.

4. The flexibly driven robot control system for hand function rehabilitation according to claim 3, wherein the training steps of the passive training mode are as follows:

step S101: setting a moving range parameter of each finger according to the moving range of the finger joint of the patient;

step S102: acquiring a preset training action mode and training times;

step S103: and displaying the training content of the preset training action mode, recording training data and uploading the training data to the server.

5. The flexibly driven robot control system for hand function rehabilitation according to claim 3, wherein the training steps of the interactive training mode are as follows:

step S201: acquiring touch point information of a display screen, and entering a corresponding myoelectric training mode or an electroencephalogram training mode;

step S202: judging whether the historical training times is 0, if so, performing off-line training, training a physiological signal through an artificial neural network, and otherwise, turning to the step S203;

step S203: judging the type of the training mode, if the training mode is an electromyographic training mode, driving the affected limb to perform gesture training through an electromyographic arm ring, if the training mode is an electroencephalographic training mode, outputting training animation through electroencephalographic head-mounted equipment to enable a patient to generate an exercise imagination signal, and extracting an electroencephalographic activity intention corresponding to the gesture exercise imagination signal through a corresponding algorithm to realize rehabilitation training of fingers;

step S204: and recording training data and uploading the training data to a server.

6. The flexibly driven hand function rehabilitation robot control system according to claim 3, wherein the training steps of the remote rehabilitation training mode are as follows:

step S301: the patient side establishes data communication with a remote server side where a rehabilitation teacher is located through a network;

step S302: acquiring mode information and judging, if the mode information is an online mode, communicating through videos, voices and characters, if the mode information is an offline mode, displaying training data uploaded to a server in a passive training mode and an interactive training mode, and generating a training scheme, wherein the training scheme comprises a training mode, times and intermediate stay time and is uploaded to the server;

step S303: the patient side displays the training regimen uploaded to the server.

7. A control method of a hand function rehabilitation robot control system based on flexible driving is characterized by comprising the following steps:

step S1: performing kinematic analysis on the hand function rehabilitation robot body, and establishing a corresponding finger motion mathematical model by adopting a system identification algorithm;

step S2: controlling the motion position in a finger motion mathematical model of the robot body by adopting a finger position control algorithm based on sliding mode control;

step S3: and performing compliance control on the gripping force of the fingers by adopting an impedance control algorithm based on a position closed loop and replacing a finger motion mathematical model of the robot body with target impedance.

8. The control method of the control system of the hand function rehabilitation robot based on the flexible drive as claimed in claim 7, wherein the finger kinematics model building step S1 specifically includes the following steps:

step S11: the rehabilitation training software (6) sends an instruction to control the hand function rehabilitation robot to do flexion and extension movement, a three-dimensional movement capturing system is used for recording the movement track of the hand function rehabilitation robot, the coordinates of each finger, metacarpophalangeal joints and fingertip are obtained, and the rotating angle of a motor shaft is synchronously obtained;

step S12: calculating the finger bending angle at each moment according to the coordinates, and calculating the Bowden cable elongation at the corresponding moment according to the direct proportional relation between the Bowden cable elongation and the angle rotated by the motor shaft;

step S13: and according to the finger bending angle data and the Bowden cable elongation data, establishing a finger motion mathematical model of the relation between the Bowden cable elongation and the finger angle of the hand function rehabilitation robot by adopting a system identification algorithm by taking the Bowden cable elongation data as input data and the finger bending angle data as output data.

9. The control method of the control system of the hand function rehabilitation robot based on the flexible drive according to claim 7, wherein the finger position control algorithm based on the sliding mode control in step S2 is provided with a sliding mode controller, and the following steps are specifically executed:

step S21: the electric control unit (3) acquires the actual position and the expected position of the finger according to AD (analog-digital) and calculates the position error of the actual position and the expected position;

step S22: obtaining a switching function of the sliding mode controller according to the position error and a derivative thereof, and calculating the elongation of the Bowden cable on each finger according to the switching function;

step S23: and adjusting the gain parameter of a sliding mode control item in the sliding mode controller by an online self-adaptive method, and controlling the movement position of the fingers of the hand function rehabilitation robot by controlling the elongation of the Bowden wire.

10. The flexibly driven hand function rehabilitation robot control system according to claim 7, wherein the impedance control algorithm based on the position closed loop in step S3 includes an inner loop and an outer loop, the inner loop is the position closed loop, the outer loop is the impedance control outer loop, and the specific implementation process is as follows:

step S31: the RFP630 bending sensor acquires the actual position information of the fingers of the patient, and the RFP603 film pressure sensor acquires the actual gripping force of the fingers;

step S32: replacing the finger movement mathematical model with a target impedance, inputting the difference value of the actual gripping force and the expected gripping force into the target impedance, and adding an impedance control outer ring on a position controller;

step S33: and calculating the difference value between the actual gripping force and the expected gripping force to obtain a position correction quantity, superposing the position correction quantity and a reference position to be used as an expected position, and tracking the expected position by the position controller to perform flexible control on the gripping force of the fingers.

Technical Field

The invention relates to the technical field of control of finger rehabilitation robots, in particular to a flexibly-driven control system and a flexibly-driven control method of a hand function rehabilitation robot.

Background

The hand training equipment such as CPM machine that has appeared on the market, although can carry out single joint training, the structure is relatively complicated, and system volume and weight are very big, and the operation is inconvenient. In addition to the products already on the market, more is in the laboratory research phase. Besides CPM, the robot is also an active repetitive motion type hand rehabilitation robot which is used for rehabilitation training of patients who reach a certain muscle strength level, the robot generally has a feedback system, and the patients can participate in the robot consciously or control the motion of the robot to a certain degree to achieve a better rehabilitation effect. For example, a hand motion assisted rehabilitation robot is driven by a motor and can train hands and wrists, but hands are required to be placed at fixed positions during training and are inconvenient to move; or the data feedback glove is driven by the cylinder and is provided with a bending sensor for detecting the bending angle of the fingers, but the moving process greatly limits the moving range of the fingers because the cylinder is in the palm; or the finger rehabilitation device is a single finger rehabilitation device, and the modules for training each finger are independent, so that the hand can be more accurately exercised, but the fingers are completely covered in the mechanical structure, so that great potential safety hazards exist; in the prior art, a research is carried out to drive a hand rehabilitation robot to adopt myoelectric control, but the system can only realize the motion training of an index finger; meanwhile, a pneumatic hand function rehabilitation robot adopts an under-actuated structural design, is made of light materials and adopts myoelectric control.

At present, the hand function rehabilitation robot control system and the product are slowly developed, and the reason analysis is as follows:

firstly, the finger structure is fine and complex, and the characteristics of high degree of freedom and flexibility bring great difficulty to the design of a rehabilitation training mechanism;

secondly, the lack of a mechanical structure causes inaccurate motion transmission, high control difficulty, low precision, slow response and poor robustness;

thirdly, the accurate real-time control of the moment, the angle and the speed of the finger joint of the patient is lacked, and the force and the position information in the training process of the hand function rehabilitation robot cannot be accurately fed back;

fourthly, the fingers of the person are parts which are easy to be injured, and how to avoid the secondary injury of the patient in the training process is also a big difficulty in the design of rehabilitation training;

and fifthly, the rehabilitation training system is lack of an evaluation system for evaluating the relationship between rehabilitation training and rehabilitation effect, which brings difficulty for further research and effective rehabilitation treatment plan formulation and accurate estimation of prognosis.

Disclosure of Invention

The invention aims to provide a flexibly-driven control system and a flexibly-driven control method for a hand function rehabilitation robot, which aim to overcome the defects of high cost, complex mechanical structure, high control difficulty, low precision, slow response, poor robustness, lack of interactive training and lack of remote guidance in the prior art.

The purpose of the invention can be realized by the following technical scheme:

a flexibly-driven hand function rehabilitation robot control system comprises rehabilitation gloves, a Bowden cable transmission mechanism, an electric control unit, a myoelectric man-machine interface unit, an electroencephalogram man-machine interface unit, rehabilitation training software and a motor driving unit which are connected with one another through electric signals, achieves movement position control and gripping force flexible control of fingers, and has the functions of remotely guiding on-line training and off-line training, and all the parts are matched with one another to complete set passive training and interactive training tasks;

the rehabilitation glove is composed of a glove body, a fingertip fixing module and a palm back fixing module, wherein the fingertip fixing module is used for fixing a Bowden cable of a Bowden cable transmission mechanism, and the palm back fixing module is used for fixing a Bowden cable tube of the Bowden cable transmission mechanism;

the bowden cable transmission mechanism consists of a disc transmission mechanism and a bowden cable traction device, one end of the bowden cable traction device is fixed on a direct current speed reduction motor of the motor driving unit, and the other end of the bowden cable traction device is fixed on the rehabilitation glove. The direct-current speed reducing motor is a direct-current speed reducing motor with an encoder, the position and the speed of the motor are fed back, double closed-loop control of the speed and the position is formed, and the buckling and the extension of fingers are driven;

the electronic control unit consists of an STM32 main control unit and a sensor unit, the sensor unit is installed on a rehabilitation glove and comprises an RFP bending sensor and an RFP force sensor, the RFP bending sensor collects the bending angle of fingers in real time to obtain the movement position information of the fingers, the movement position information of the fingers is converted into a motor driving instruction through a position controller to complete the position control of the fingers, the RFP force sensor collects the gripping force information of the fingers in real time and converts the gripping force information of the fingers into the motor driving instruction through a force controller to complete the flexible control of the gripping force of the fingers, the electronic control unit uploads the processed sensor data to rehabilitation training software, and the rehabilitation training software uploads the data to a server;

the rehabilitation training software sends a corresponding command to the electric control unit, the electric control unit analyzes the received command into a corresponding training parameter, the position controller or the force controller is selected to convert the position or the force into a driver control command, and the motor driving unit is controlled to drive the Bowden cable transmission mechanism to transmit traction force generated by the motor to the hand of the patient through the rehabilitation glove.

The myoelectric human-computer interface unit is connected with rehabilitation training software in a Bluetooth mode and is provided with a myoelectric arm ring, surface myoelectric signals on the arm of a patient are collected through the myoelectric arm ring, amplified and adjusted, input to an STM32 processor for AD sampling, band-pass filtering is carried out on two collected paths of surface myoelectric signals by using a digital filter, four time domain and frequency domain characteristic values are respectively extracted to form an eight-dimensional characteristic matrix, the eight-dimensional characteristic matrix is led into a BP classification model to obtain corresponding weight and threshold coefficients, finally, the STM32 main control unit carries out corresponding operation on the weight and the threshold to obtain a corresponding action online recognition result, outputs control signals in real time, and sends the output control signals to the rehabilitation training software to control a rehabilitation robot body to execute corresponding actions.

The control system is provided with three training modes which are respectively a passive training mode, an interactive training mode and a remote rehabilitation training mode according to the hemiplegia degree of the affected limb of the patient, wherein the passive training mode is used for driving the finger of the patient to do corresponding action; the interactive training mode is divided into a myoelectric interactive system and an electroencephalogram interactive system, and rehabilitation training is completed by using the physiological signal of the patient, so that active training is completed; the remote rehabilitation training mode refers to the fact that a patient end is in contact with a remote server end where a rehabilitation teacher is located through a network and comprises an online mode and an offline mode, the online mode specifically refers to the fact that video, voice and characters are communicated, the training condition of the patient is fed back in real time, and the offline mode refers to the fact that historical data corresponding to the patient stored in a server are displayed.

Further, the training steps of the passive training mode are specifically as follows:

step S101: setting a moving range parameter of each finger according to the moving range of the finger joint of the patient;

step S102: acquiring a preset training action mode and training times;

step S103: and displaying the training content of the preset training action mode, recording training data and uploading the training data to the server.

Further, the training steps of the interactive training mode are specifically as follows:

step S201: acquiring touch point information of a display screen, and entering a corresponding myoelectric training mode or an electroencephalogram training mode;

step S202: judging whether the historical training times is 0, if so, performing off-line training, training a physiological signal through an artificial neural network, and otherwise, turning to the step S203;

step S203: judging the type of the training mode, if the training mode is an electromyographic training mode, driving the affected limb to perform gesture training through an electromyographic arm ring, if the training mode is an electroencephalographic training mode, outputting training animation through electroencephalographic head-mounted equipment to enable a patient to generate an exercise imagination signal, and extracting an electroencephalographic activity intention corresponding to the gesture exercise imagination signal through a corresponding algorithm to realize rehabilitation training of fingers;

step S204: and recording training data and uploading the training data to a server.

Further, the training steps of the remote rehabilitation training mode are as follows:

step S301: the patient side establishes data communication with a remote server side where a rehabilitation teacher is located through a network;

step S302: acquiring mode information and judging, if the mode information is an online mode, communicating through videos, voices and characters, if the mode information is an offline mode, displaying training data uploaded to a server in a passive training mode and an interactive training mode, and generating a training scheme, wherein the training scheme comprises a training mode, times and intermediate stay time and is uploaded to the server;

step S303: the patient side displays the training regimen uploaded to the server.

A control method of a hand function rehabilitation robot control system based on flexible driving specifically comprises the following steps:

step S1: performing kinematic analysis on the hand function rehabilitation robot body, and establishing a corresponding finger motion mathematical model by adopting a system identification algorithm;

step S2: controlling the motion position in a finger motion mathematical model of the robot body by adopting a finger position control algorithm based on sliding mode control;

step S3: and performing compliance control on the gripping force of the fingers by adopting an impedance control algorithm based on a position closed loop and replacing a finger motion mathematical model of the robot body with target impedance.

The finger kinematics model establishing step S1 specifically includes the following steps:

step S11: the rehabilitation training software sends an instruction to control the hand function rehabilitation robot to do flexion and extension movement, a three-dimensional movement capturing system is used for recording the movement track of the hand function rehabilitation robot, the coordinates of each finger, each metacarpophalangeal joint and each fingertip are obtained, and the angle of the motor shaft is synchronously obtained;

step S12: calculating the finger bending angle at each moment according to the coordinates, and calculating the Bowden cable elongation at the corresponding moment according to the direct proportional relation between the Bowden cable elongation and the angle rotated by the motor shaft;

step S13: and according to the finger bending angle data and the Bowden cable elongation data, establishing a finger motion mathematical model of the relation between the Bowden cable elongation and the finger angle of the hand function rehabilitation robot by adopting a system identification algorithm by taking the Bowden cable elongation data as input data and the finger bending angle data as output data.

Further, the sliding mode controller is provided in the step S2 based on the sliding mode control finger position control algorithm, and specifically the following steps are executed:

step S21: the electronic control unit acquires the actual position and the expected position of the finger according to the AD and calculates the position error of the actual position and the expected position;

step S22: obtaining a switching function of the sliding mode controller according to the position error and a derivative thereof, and calculating the elongation of the Bowden cable on each finger according to the switching function;

step S23: and adjusting the gain parameter of a sliding mode control item in the sliding mode controller by an online self-adaptive method, and controlling the movement position of the fingers of the hand function rehabilitation robot by controlling the elongation of the Bowden wire.

Further, the impedance control algorithm based on the position closed loop in step S3 includes an inner loop and an outer loop, where the inner loop is the position closed loop and the outer loop is an impedance control outer loop, and the specific implementation process is as follows:

step S31: the RFP630 bending sensor acquires the actual position information of the fingers of the patient, and the RFP603 film pressure sensor acquires the actual gripping force of the fingers;

step S32: replacing the finger movement mathematical model with a target impedance, inputting the difference value of the actual gripping force and the expected gripping force into the target impedance, and adding an impedance control outer ring on a position controller;

step S33: and calculating the difference value between the actual gripping force and the expected gripping force to obtain a position correction quantity, superposing the position correction quantity and a reference position to be used as an expected position, and tracking the expected position by the position controller to perform flexible control on the gripping force of the fingers.

Compared with the prior art, the invention has the following beneficial effects:

according to the invention, the rehabilitation gloves, the Bowden cable transmission mechanism, the electric control unit, the myoelectric man-machine interface unit, the electroencephalogram man-machine interface unit, the rehabilitation training software and the motor driving unit are matched with each other, so that the motion position control and the gripping force control of five fingers are realized, the hand function rehabilitation robot drives the hand of a patient to perform rehabilitation training, the process is more flexible, stable and accurate, the patient is helped to complete passive training and interactive training tasks, and meanwhile, the functions of remote guidance on-line training and off-line training are provided, so that the rehabilitation effect of the patient is improved, and the rehabilitation process is accelerated.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic view of kinematic analysis of an index finger according to the present invention;

FIG. 3 is a schematic diagram of the finger position control of the present invention;

FIG. 4 is a flow chart of a position control algorithm of the present invention;

FIG. 5 is a schematic diagram of the impedance control based on the position controller according to the present invention;

FIG. 6 is a flow chart of an impedance control algorithm of the present invention;

FIG. 7 is a graph of the dynamic tracking of index finger position during flexion/extension training of the present invention;

FIG. 8 is a graph of the tracking of the index finger's grip when gripping a cup in accordance with the present invention;

FIG. 9 is a flow chart of the passive training mode of the present invention;

FIG. 10 is a flow chart of the remote rehabilitation training mode of the present invention.

Reference numerals:

1-rehabilitation gloves; 2-bowden cable transmission; 3-an electronic control unit; 4-myoelectric human-computer interface unit; 5-brain electrical human-computer interface unit; 6-rehabilitation training software; 7-motor drive unit.

Detailed Description

The invention is described in detail below with reference to the figures and specific embodiments. The present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the scope of the present invention is not limited to the following embodiments.

As shown in fig. 1, a flexibly-driven control system of a hand function rehabilitation robot for realizing motion position control and gripping force control of five fingers, so that the hand function rehabilitation robot drives the hand of a patient to perform rehabilitation training more flexibly, stably and accurately, comprises a rehabilitation glove 1, a bowden cable transmission mechanism 2, an electric control unit 3, a myoelectric human-computer interface unit 4, an electroencephalogram human-computer interface unit 5, rehabilitation training software 6 and a motor driving unit 7 which are connected with each other through electric signals, realizes the motion position control and gripping force flexible control of the fingers, and is matched with each other to finish set passive training and interactive training tasks, thereby having the functions of remote guidance on-line training and off-line training;

the rehabilitation glove 1 consists of a glove body, a fingertip fixing module and a palm back fixing module, wherein the fingertip fixing module is used for fixing a Bowden cable of the Bowden cable transmission mechanism 2, and the palm back fixing module is used for fixing a Bowden cable tube of the Bowden cable transmission mechanism 2;

the Bowden cable transmission mechanism 2 consists of a disc transmission mechanism and a Bowden cable traction device, one end of the Bowden cable traction device is fixed on a direct current speed reducing motor of the motor driving unit 7, and the other end of the Bowden cable traction device is fixed on the rehabilitation glove 1. The direct-current speed reducing motor is a direct-current speed reducing motor with an encoder, the position and the speed of the motor are fed back, double closed-loop control of the speed and the position is formed, and the fingers are driven to bend and extend;

the electric control unit 3 is composed of an STM32 main control unit and a sensor unit, the sensor unit is installed on the rehabilitation glove 1 and comprises an RFP bending sensor and an RFP force sensor, the RFP bending sensor collects the bending angle of fingers in real time to obtain the motion position information of the fingers, the motion position information is converted into a motor driving instruction through a position controller to complete the position control of the fingers, the RFP force sensor collects the gripping force information of the fingers in real time and converts the gripping force information into the motor driving instruction through a force controller to complete the flexible control of the gripping force of the fingers, the electric control unit 3 uploads the processed sensor data to the rehabilitation training software 6, and the rehabilitation training software 6 uploads the data to a server for a rehabilitation teacher to check and call;

the rehabilitation training software 6 sends a corresponding command to the electric control unit 3, the electric control unit 3 analyzes the received command into a corresponding training parameter, the position controller or the force controller is selected to convert the position or the force into a driver control command, and the motor driving unit 7 is controlled to drive the Bowden cable transmission mechanism 2 to transmit the traction force generated by the motor to the hand of the patient through the rehabilitation glove 1.

The myoelectric human-computer interface unit 4 is connected with the rehabilitation training software 6 in a Bluetooth mode and is provided with a myoelectric arm ring, surface myoelectric signals on the arm of a patient are collected through the myoelectric arm ring, amplified and adjusted, input to an STM32 processor for AD sampling, band-pass filtering is carried out on two collected surface myoelectric signals by using a digital filter, four time domain and frequency domain characteristic values are respectively extracted to form an eight-dimensional characteristic matrix, the eight-dimensional characteristic matrix is led into a BP classification model to obtain corresponding weight and threshold coefficients, finally, the STM32 main control unit carries out corresponding operation on the weight and the threshold to obtain a corresponding action online recognition result, outputs control signals in real time, and sends the output control signals to the rehabilitation training software 6 to control the rehabilitation robot body to execute corresponding actions.

The myoelectric arm ring is positioned on the healthy side or the affected side of the patient, and if the patient is in the early stage of hemiplegia, the myoelectric arm ring is arranged on the healthy side due to weak myoelectric signals of the affected side, so that a passive training mode that the healthy side drives the affected side and is realized by the myoelectric arm ring can be completed; if the patient has the autonomous movement ability of the fingers, the myoelectric arm ring is arranged on the affected side to complete the active training mode driven by the physiological signals on the surface of the patient.

The electroencephalogram human-computer interface unit 5 is connected with the rehabilitation training software 6 in a Bluetooth mode, the EPOC + electroencephalogram head-mounted equipment is adopted to collect electroencephalogram signals of a wearer under animation stimulation, average bandwidth energy of alpha and beta frequency bands is extracted, the average bandwidth energy of each action is used as the characteristics of electroencephalogram imagination movement, then an LS-SVM classification algorithm is used for classification and identification, and finally electroencephalogram activity intentions are extracted.

The control system is provided with three training modes which are respectively a passive training mode, an interactive training mode and a remote rehabilitation training mode according to the hemiplegia degree of the affected limb of the patient, wherein the passive training mode is used for driving the finger of the patient to do corresponding action; the interactive training mode is divided into a myoelectric interactive system and an electroencephalogram interactive system, and the rehabilitation training is completed by utilizing the physiological signals of the patient, so that the active training is completed; the remote rehabilitation training mode refers to the fact that a patient end is in contact with a remote server end where a rehabilitation teacher is located through a network and comprises an online mode and an offline mode, the online mode specifically refers to the fact that video, voice and characters are communicated, the training condition of the patient is fed back in real time, the offline mode refers to the fact that corresponding historical data of the patient stored in a server are displayed, the rehabilitation teacher can check the historical training data of the patient and give a further training plan, and the patient can be guided by the remote rehabilitation teacher when being at home in time.

As shown in fig. 9, the training steps of the passive training mode are as follows:

step S101: setting a moving range parameter of each finger according to the moving range of the finger joint of the patient;

step S102: acquiring a preset training action mode and training times;

step S103: and displaying the training content of the preset training action mode, recording training data and uploading the training data to the server.

The training steps of the interactive training mode are as follows:

step S201: acquiring touch point information of a display screen, and entering a corresponding myoelectric training mode or an electroencephalogram training mode;

step S202: judging whether the historical training times is 0, if so, performing off-line training, training a physiological signal through an artificial neural network, and otherwise, turning to the step S203;

step S203: judging the type of the training mode, if the training mode is an electromyographic training mode, driving the affected limb to perform gesture training through an electromyographic arm ring, if the training mode is an electroencephalographic training mode, outputting training animation through electroencephalographic head-mounted equipment to enable a patient to generate an exercise imagination signal, and extracting an electroencephalographic activity intention corresponding to the gesture exercise imagination signal through a corresponding algorithm to realize rehabilitation training of fingers;

step S204: and recording training data and uploading the training data to a server.

As shown in fig. 10, the training steps of the remote rehabilitation training mode are as follows:

step S301: the patient side establishes data communication with a remote server side where a rehabilitation teacher is located through a network;

step S302: acquiring mode information and judging, if the mode information is an online mode, communicating through videos, voices and characters, if the mode information is an offline mode, displaying training data uploaded to a server in a passive training mode and an interactive training mode, and generating a training scheme by a rehabilitation teacher according to the training data and the training state of a patient, wherein the training scheme comprises a training mode, times and intermediate stay time and is uploaded to the server;

step S303: and the patient end displays the training scheme uploaded to the server, and the patient performs rehabilitation training according to the training scheme.

A control method of a hand function rehabilitation robot control system based on flexible driving specifically comprises the following steps:

step S1: performing kinematic analysis on the hand function rehabilitation robot body, establishing a relation model between the Bowden cable elongation and the finger joint angle, and establishing a corresponding finger motion mathematical model by adopting a system identification algorithm;

step S2: controlling the motion position in a finger motion mathematical model of the robot body by adopting a finger position control algorithm based on sliding mode control;

step S3: and performing compliance control on the gripping force of the fingers by adopting an impedance control algorithm based on a position closed loop and replacing a finger motion mathematical model of the robot body with target impedance.

The finger kinematics model building step S1 specifically includes the following steps:

step S11: the rehabilitation training software 6 sends an instruction to control the hand function rehabilitation robot to do flexion and extension movement, a three-dimensional movement capturing system is used for recording the movement track of the hand function rehabilitation robot, the coordinates of each finger, metacarpophalangeal joints and fingertip are obtained, and the rotating angle of a motor shaft is synchronously obtained;

step S12: calculating the finger bending angle at each moment according to the coordinates, and calculating the Bowden cable elongation at the corresponding moment according to the direct proportional relation between the Bowden cable elongation and the angle rotated by the motor shaft;

step S13: according to the data of the finger bending angle and the data of the Bowden cable elongation, the data of the Bowden cable elongation is used as input data, the data of the finger bending angle is used as output data, and a system identification algorithm is adopted to establish a finger motion mathematical model of the relation between the Bowden cable elongation and the finger angle of the hand function rehabilitation robot.

The method for capturing the finger motion track by the Vicon motion capture system to acquire the coordinates of the mark points comprises the following steps:

step S111: adjusting the angle of a camera of the motion capture system, acquiring the positions of 8 cameras, adjusting the relative positions of the cameras and the hand function rehabilitation robot, and ensuring that the visual field is in a lower middle position;

step S112: adjusting camera parameters, wherein the strength of emitted infrared rays is controlled by the size of the camera parameters, so that the camera parameters need to be adjusted one by one according to actual use scenes to ensure that only mark points stably appear in a visual field;

step S113: observing the picture of each camera in control software, adjusting and removing invalid points one by one, and covering invalid points which cannot be removed by using an eraser tool;

step S114: when the experiment is started each time, after the camera is moved, before the rigid body is modeled, the calibration is carried out again;

step S115: selecting a data storage location;

step S116: attaching a light-reflecting ball to a position corresponding to a finger, placing the light-reflecting ball in a detection space, establishing a blank model, then starting acquisition, reconstructing a three-dimensional model after one second of acquisition, establishing a rigid body model by connecting mark points in a picture, and storing data of the established rigid body model;

step S117: collecting data of a finger motion track;

step S118: opening the recorded data, reconstructing the rigid body model, and then playing the acquired data for return visit data;

step S119: and saving and outputting the acquired data into a csv format, and outputting the acquired data at the corresponding position of the saving file.

As shown in FIG. 2, the finger kinematics analysis using the index finger as an example proves that the mathematical relationship between the finger bending angle θ measured by the indirect method and the actual bending angles of the three joints of the finger is correct.

As shown in fig. 2, points D and D₁Length between is l₁Point D₁And point D₂Length between is l₂Points D and D₂Has a length of l between₃Length between point D and point A is l₄Length between point A and point B is l₅Points B and D₂Length between is l₆Points A and D₂Length between is l₇Let the bending angle of the index finger MP joint be θ₁The bending angle of the PIP joint is recorded as θ₂The bending angle of the DIP joint is represented by θ₃Segment l is divided into₄The straight line and the line segment l₃The included angle of the straight line is marked as theta₄Line segment l₁The straight line and the line segment l₃The included angle of the straight line is marked as theta. From the above definition of each point and each line segment length, it can be obtained by using the geometrical method:

is obtained by the above formula

PIP (Angle θ)₂) Following MP (angle is theta)₁) Joint, DIP (Angle θ)₃) The joint angle coupling relationship with motion of the PIP joint is as follows:

in the two formulas, theta is in one-to-one correspondence with the actual bending angle of the finger joint. Therefore, the bending angle of the finger joint is converted into the angle theta, and the angle theta is called as the finger bending angle of the flexible driving hand function rehabilitation robot.

In step S12, the finger bending angle is calculated, taking the index finger as an example, the rehabilitation training software 6 sends an instruction to control the motion of the hand function rehabilitation robot, the Vicon motion capture system captures each motion trajectory in the finger motion range to obtain the coordinates of the mark points, and the finger bending angle is calculated according to the following formula:

wherein (x)₀，y₀，z₀) As the coordinates of the marker point D, (x)₁，y₁，z₁) And (x)₂，y₂，z₂) Respectively as auxiliary mark points D₁And D₂Coordinate of (a), (b), and (c)₁For marking point D and auxiliary marking point D₁A distance of l₂Marking points D for assistance₂And auxiliary mark point D₁A distance of l₃Marking points D for assistance₂And the distance from the mark point D, and theta is the bending angle of the finger of the index finger.

Meanwhile, in step S12, the number of pulse signals of the motor shaft rotation angle is read and recorded from the dc geared motor with the photoelectric encoder, the elongation of the bowden cable is calculated, the elongation of the bowden cable is proportional to the rotation angle of the motor shaft, and the rotation angle of the motor shaft is represented by the number of pulses detected by the photoelectric encoder, and the elongation of the bowden cable is obtained from the number of pulse signals fed back, according to the following formula:

L＝R×θ₀＝k₀×R×N

where R is the radius of the disk of the dc gear motor, where R is 2.5cm, θ is the elongation of the bowden cable₀Is the rotation angle of the motor; k is a radical of₀The proportionality coefficient of the motor shaft rotation angle and the number of pulse signals, in this embodiment

The hand function rehabilitation robot shows nonlinear characteristics in actual operation, a method of partially linearizing a nonlinear system is adopted, the dynamic performance of the nonlinear system is approximately represented by a linear model, the index Bowden wire elongation is used as input, the index bending angle is used as output, and a least square identification algorithm is adopted to obtain an index dynamic characteristic equation model of the hand function rehabilitation robot, wherein the index dynamic characteristic equation model is as follows:

y(t)＝0.993y(t-1)-0.012y(t-2)+0.3115u(t-2)

where y (t) is the finger bending angle of the index finger at time t, and u (t) is the Bowden wire elongation of the index finger at time t.

In step S2, a sliding mode controller is provided in the sliding mode control based finger position control algorithm, and the specific implementation steps are as shown in fig. 4:

step S21: the electric control unit 3 acquires the actual position and the expected position of the finger according to AD, and calculates the position error of the actual position and the expected position;

step S22: obtaining a switching function of the sliding mode controller according to the position error and a derivative thereof, and calculating the elongation of the Bowden cable on each finger according to the switching function;

step S23: and adjusting the gain parameter of a sliding mode control item in the sliding mode controller by an online self-adaptive method, and controlling the movement position of the fingers of the hand function rehabilitation robot by controlling the elongation of the Bowden wire.

The working principle of the sliding mode controller is shown in fig. 3, and the position control of the fingers of the hand function rehabilitation robot is realized by controlling the elongation of the bowden cable, wherein r is the expected position of the fingers of the hand function rehabilitation robot, the output quantity L of the sliding mode controller is the elongation of the bowden cable, and θ is the actual position of the fingers collected by the RFP bending sensor. When the position error and the derivative thereof pass through the sliding hyperplane of the state space, the feedback control structure of the system changes according to the sliding mode controller, so that the performance of the control system reaches the expected performance index.

For the index finger as an example, the dynamic equation for the index finger:

wherein θ is the index finger state vector, L is the bowden cable elongation, i.e. the control quantity, L (θ, t), and t ∈ R switches on the switching plane s (θ, t) ═ 0, and the specific relationship is as follows:

where s (θ, t) is a switching function, which is a smooth continuous function.

The sliding mode controller satisfies the following constraints:

where ds is the integral of the switching function.

The initial point theta (0) of the index finger of the hand function rehabilitation robot is an arbitrary position of the index finger state space, if the initial point is not near the sliding mode switching surface s which is 0, the initial point is moved to the position near the sliding mode switching surface according to the arrival stage, and a corresponding Lyapunov function V (theta) is selected as follows:

and make a derivative thereof

When the following condition is satisfied, the motion of the system will satisfy the accessibility condition, and finally reach and stabilize on the sliding mode surface s being 0, where the specific condition is:

the step S21 of calculating the position error specifically includes:

setting the state variable of the sliding mode controller as e,

wherein e is the positional deviation of the index finger，

As a derivative of the position deviation, the following condition is satisfied:

wherein r is the expected position state vector of the index finger, theta is the state vector of the index finger,the derivative of the state vector for the index finger.

Setting a state vector x ═ x₁,x₂]^TWherein:

since the hand function rehabilitation robot system is discrete in actual movement, the robot system will be used for the rehabilitation of hand functionDiscretizing to obtain a discretization equation:

X(k)＝[e(k),e(k+1)]^T＝[x₁(k),x₂(k)]^T

wherein k is 1,2, …, and N is a positive integer.

Substituting the dynamic characteristic equation model and the state vector of the index finger of the hand function rehabilitation robot into the discretization equation to obtain the state equation of the control system as follows:

X(k+1)＝AX(k)+Bu(k)

wherein the content of the first and second substances,

the index approximation rule of the continuous sliding mode control is as follows:

wherein, and q are process parameters.

Discretizing the data to obtain a sliding mode control index approach law of a discrete system shown as the following formula:

wherein the content of the first and second substances,and p is less than 1 and T is less than 1.

Obtaining the control index approximation law according to the sliding mode of a discrete systemThe corresponding Lyapunov function was chosen as follows:

the following constraints are satisfied:

according to the lyapunov theorem of stability, when s (k) is 0, any initial position of the state space approaches to the switching surface s (k), and the arrival condition of the discrete sliding mode is as follows:

s(k+1)²＜s(k)²

when in useThen, the control system meets the discrete sliding mode arrival condition to obtain

When in useWhen p is-1, i.e., | p | ═ 1, | s (k +1) | ═ 1| s (k) |, s (k) enter an oscillation state.

When in use

When p < -1, i.e., | p | > 1, | s (k +1) | > | s (k) |.

When the sliding mode arrival condition is met by the control system,at this timeTo obtain

Wherein the content of the first and second substances,

at this time

The improved discrete approach law is:

the switching function is a linear function, which is specifically as follows:

s(k)＝CX(k)

wherein C is a linear coefficient;

substituting the state equation of the control system into the linear switching function to obtain:

s(k+1)＝CX(k+1)＝C(AX(k)+Bu(k))

the output of the sliding mode controller for solving the forefinger is

In order to further prevent the controller from generating a buffeting phenomenon, a saturation function method is adopted to replace a sign function sgn(s) in an ideal sliding mode approaching law with a saturation function sat(s), and the structure of the saturation function sat(s) is as follows:

wherein, Delta is the thickness of the boundary layer, and the value is a normal number.

The discrete sliding mode control law therefore becomes:

in step S3, the impedance control algorithm based on the position closed loop includes an inner loop and an outer loop, where the inner loop is the position closed loop and the outer loop is the impedance control outer loop, as shown in fig. 6, the specific implementation process is as follows:

step S31: the RFP630 bending sensor acquires the actual position information of the fingers of the patient, and the RFP603 film pressure sensor acquires the actual gripping force of the fingers;

step S32: replacing a finger movement mathematical model with target impedance, inputting the difference value of actual gripping force and expected gripping force into the target impedance, and adding an impedance control outer ring on a position controller;

step S33: and calculating the difference value between the actual gripping force and the expected gripping force to obtain a position correction amount, superposing the position correction amount and the reference position as an expected position, tracking the expected position by the position controller, and performing flexible control on the gripping force of the fingers.

As shown in fig. 5, the specific process of calculating by the target impedance is as follows:

setting the desired target impedance of the finger to Z, the dynamic relationship between the desired grip force and the finger position is:

Z(X_r-X)＝-F

wherein, X_rIs a reference position of the finger; x is the actual position of the finger; f is the acting force between the fingers and the gripped object;

the impedance form is set as a mass-spring-damping system, and the target impedance is expressed by a second-order differential equation, which is as follows:

wherein M is_dDesired inertia matrix for the control system, B_dDesired damping matrix for control system, K_dA desired stiffness matrix for the control system.

Adding the expected gripping force F of the finger on the basis of a second order differential equation_dAnd will receive the grip error signal F_e＝F_dF as the driving quantity of the finger target impedance model to achieve the tracking of the expected gripping force, the improved target impedance model is:

let X_f＝X_rX, simplifying the improved target impedance model to:

the simplified target impedance model is subjected to Laplace transform to obtain the representation form of the target impedance of the finger on the frequency domain as follows:

(M_ds²+B_ds+K_d)X_f(s)＝F_e(s)

the position correction amount of the finger obtained by the method is as follows:

position correction X_fAnd a reference position X_rThe sum is used as the corrected desired position of the finger.

Since the motion direction of the hand function rehabilitation robot is one-dimensional, only one direction is considered, and the target impedance is simplified as follows:

wherein m is_d，b_d，k_dThe parameters are inertia parameter, damping parameter and rigidity parameter.

The representation form of the finger in the frequency domain obtained after the Laplace transform is as follows:

the position-based finger target impedance model obtained thereby is:

converting the position-based finger target impedance model into a standard type represented by the following formula through multiplicative transformation:

wherein, ω is_nZeta is the damping ratio for undamped natural frequency, and specifically is as follows:

in order to improve the flexibility of the gripping action of the hand function rehabilitation robot, the impedance model is expected to exhibit a short adjustment time without overshoot and oscillation characteristics, and therefore the target impedance model is set to a critical damping state.

As shown in fig. 7 and 8, the position control experiment and the gripping force control experiment are performed on the hand function rehabilitation robot control system, the steady-state precision of the finger bending angle can reach 2 degrees under the self-adaptive sliding mode position control, and the rising time of the control system reaches 0.47 s; under the impedance control based on the self-adaptive sliding mode position control, the steady-state precision of the finger gripping force reaches 0.6N, the rising time of the control system reaches 0.27s, the characteristics of high precision and quick response of the hand function rehabilitation robot control system are verified, and the control system has good robustness.

In addition, it should be noted that the specific embodiments described in the present specification may have different names, and the above descriptions in the present specification are only illustrations of the structures of the present invention. All equivalent or simple changes in the structure, characteristics and principles of the invention are included in the protection scope of the invention. Various modifications or additions may be made to the described embodiments or methods may be similarly employed by those skilled in the art without departing from the scope of the invention as defined in the appending claims.