CN109015649B - Hydraulic exoskeleton robot control system and method for realizing rhythmic compliant motion - Google Patents
Hydraulic exoskeleton robot control system and method for realizing rhythmic compliant motion Download PDFInfo
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- CN109015649B CN109015649B CN201810965149.1A CN201810965149A CN109015649B CN 109015649 B CN109015649 B CN 109015649B CN 201810965149 A CN201810965149 A CN 201810965149A CN 109015649 B CN109015649 B CN 109015649B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1615—Programme controls characterised by special kind of manipulator, e.g. planar, scara, gantry, cantilever, space, closed chain, passive/active joints and tendon driven manipulators
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B25—HAND TOOLS; PORTABLE POWER-DRIVEN TOOLS; MANIPULATORS
- B25J—MANIPULATORS; CHAMBERS PROVIDED WITH MANIPULATION DEVICES
- B25J9/00—Programme-controlled manipulators
- B25J9/16—Programme controls
- B25J9/1628—Programme controls characterised by the control loop
Abstract
The invention relates to a control system and a method for realizing the rhythm compliant motion of an exoskeleton robot, wherein the control system comprises a perception and planning system, a servo control system and a power supply system; the perception and planning system comprises a perception and planning processor, a plantar pressure acquisition module, a man-machine interaction force acquisition module, an inertial sensor module and a man-machine interaction interface; the servo control system comprises an executive layer controller, an electro-hydraulic driving system, a feedback measuring unit and a robot body module; the gait pattern generator generates reference motion tracks of all joints in a unified and coordinated manner; the execution layer controller comprises a force control algorithm and a position control algorithm. The invention adopts a hierarchical and distributed control system, and not only improves the reliability and the real-time performance of the system, but also can improve the flexibility and the agility of the exoskeleton robot by reasonably distributing the calculated amount of each part.
Description
Technical Field
The invention belongs to the technical field of robot control, relates to an exoskeleton robot control system and a control method, and particularly relates to an exoskeleton robot control system and a method capable of realizing flexible hydraulic drive.
Background
The exoskeleton robot is an intelligent human-computer interaction system, can effectively enhance the human body load capacity, and has wide application prospects in the fields of individual-soldier maneuvering operation, disaster relief and rescue and rehabilitation medical treatment. Exemplary international exoskeleton robot applications include XOS and HULC of the advanced research project agency of the united states department of Defense (DAPRA), FORTIS of rockschidman, Rewalk of israel, and HAL of japan bubo university, among others. In recent years, research and development of exoskeleton robots have been carried out in different application scenes by domestic research institutes such as Chinese weapon group companies, Chinese ship re-engineering group companies, Harbin industrial university, Beijing research institute, Chinese academy of sciences and the like.
The control system is one of the most critical links for determining the performance indexes of the exoskeleton robot. Conventional control strategies typically place, force, or force-position hybrid control for each kinematic joint individually, focusing on local control of the underlying joints of the robot. In the control mode, the exoskeleton joint movement can be regarded as a simple reflex movement, and a top-level and global coordination control strategy among all joints is lacked, so that the existing exoskeleton robot has poor adaptability to a wearer, serious interference problem among human and machine, and stiff walking action of the human and machine.
Disclosure of Invention
The invention aims to provide a control system and a control method which are reasonable in design, high in reliability and strong in real-time performance and can realize the smooth and flexible movement of the exoskeleton robot rhythm.
The invention solves the practical problem by adopting the following technical scheme:
a hydraulic exoskeleton robot control system for realizing rhythmic compliant motion comprises a sensing and planning system, a servo control system and a power supply system;
the sensing and planning system comprises a sensing and planning processor, a plantar pressure acquisition module, a man-machine interaction force acquisition module, an inertial sensor data acquisition module and a man-machine interaction interface; the output end of the plantar pressure acquisition module is connected with the perception and planning processor and is used for measuring the distribution of plantar pressure in time and space; the output end of the human-computer interaction force acquisition module is connected with the perception and planning processor and is used for measuring contact force information between the thigh and the exoskeleton of the wearer; the output end of the inertial sensor data acquisition module is connected with the perception and planning processor and is used for measuring the posture information of the lower limbs, the small limbs and the upper limbs of the wearer; the human-computer interaction interface and the perception and planning processor are connected and used for capturing, transmitting and displaying human-computer data interaction; the perception and planning processor comprises a DSP processing module and an FPGA interface module, the output end of the perception and planning processor is connected with the servo control system and used for receiving the output data of each acquisition module, carrying out online comprehensive analysis on the human motion gait, generating the motion reference track and the control mode of each joint of the robot on line and outputting the reference track and the control mode to the servo control system;
the servo control system comprises an executive layer controller, an electro-hydraulic driving system, a feedback measuring unit and a robot body module; the execution layer controller comprises a DSP processing module and an FPGA interface module; the electro-hydraulic driving system consists of a hydraulic pump motor driving plate, a servo valve motor driving plate and a hydraulic system; the FPGA interface module of the executive layer controller receives data of each sensor in the robot feedback measurement unit and outputs the data to the DSP processing module of the executive layer controller; the output end of the DSP processing module of the execution layer controller is connected with the hydraulic system through a hydraulic pump motor drive board and a servo valve motor drive board and is used for outputting control signals of a hydraulic pump motor and a servo valve motor so as to control the hydraulic system to actuate; the output end of the hydraulic system is connected with the robot body module and used for driving each joint module of the robot body to move; the hip joint and knee joint angle encoder on the robot body is connected with the FPGA interface module of the executive layer controller and used for outputting the hip joint angle and the knee joint angle of the robot body to the FPGA interface module of the executive layer controller for feedback; a hydraulic pump rotating speed encoder, a servo valve angle encoder, a hip cylinder oil pressure sensor and a knee cylinder oil pressure sensor on the hydraulic system are connected with the FPGA interface module of the executive layer controller and are used for outputting a hydraulic pump rotating speed, a servo valve opening degree, a robot hip cylinder pressure signal and a robot knee cylinder pressure signal of the hydraulic system to the FPGA interface module of the executive layer controller for feedback; the hydraulic pump motor and the servo valve motor are connected with the FPGA interface module of the executive layer controller through current sensors and are used for outputting current signals of the hydraulic pump motor and the servo valve motor to the FPGA interface module of the executive layer controller for feedback;
and the output end of the power supply system is respectively connected with the sensing and planning system and the servo control system and supplies power to the sensing and planning system and the servo control system.
A hydraulic exoskeleton robot control method for realizing rhythmic compliant motion comprises the following steps:
and 6, performing dynamic modeling on the exoskeleton robot system by using a Lagrange method in a force control mode to obtain expected torque of each joint of the exoskeleton under a given reference track, and acquiring oil pressure in a hydraulic cylinder as feedback to perform force closed-loop control.
Moreover, the specific method of step 1 is: the foot pressure acquisition module and the human-computer interaction force acquisition module respectively send foot pressure information and human-computer interaction force information to the sensing and planning processor through a CAN bus interface, the inertial sensor data acquisition module sends wearer posture information to the sensing and planning processor through a Bluetooth interface, and the human-computer interaction interface sends control parameters set by a wearer to the sensing and planning processor through a serial port;
moreover, the specific method of the step 2 is as follows: the perception and planning processor carries out filtering and feature extraction on the input plantar pressure signal, the human-computer interaction force signal and the wearer posture signal, and extracts gait phase, stride and gait cycle, interaction force between the wearer and the exoskeleton and feature variables of the wearer posture angle respectively.
Further, the specific steps of step 3 include:
(1) constructing a gait pattern generator in a perception and planning processor, wherein the gait pattern generator consists of four functional neuron network nuclei which are mutually coupled and respectively corresponds to a left hip joint, a left knee joint, a right hip joint and a right knee joint motion trail generation unit;
(2) inputting the external sensing signal characteristic variables extracted in the step (2) to a functional neuron network nucleus in a gait pattern generator to serve as external excitation;
(3) and the gait pattern generator performs learning training, the synaptic weights among the neuron network nuclei are continuously updated until the synaptic weights converge to a steady state value, and then the average field potentials output by the four neuron network nuclei are respectively used as reference motion tracks of the left hip joint, the left knee joint, the right hip joint and the right knee joint.
Further, the specific steps of step 5 include:
(1) hip joint angular position control: the hip joint angle, the opening of a servo valve and the pressure of a hip hydraulic cylinder are adopted to form a three-closed-loop control system, wherein a pressure sensor in the hip hydraulic cylinder senses the change of the hip load pressure firstly, a pressure closed loop of the hydraulic cylinder is set as an innermost loop, a rotating speed closed loop of a hydraulic pump is used as a second-layer closed loop, and the hip joint angle as a final control target is an outermost control closed loop;
(2) knee joint angular position control: the three-closed-loop control system is formed by knee joint angle, hydraulic servo valve opening and knee hydraulic cylinder pressure, wherein a pressure sensor in the knee hydraulic cylinder senses knee load change firstly, so that the knee pressure closed loop is used as the innermost loop of the control system; the outer layer is a servo valve opening closed loop, and the outermost layer is a knee joint angle control closed loop.
The invention has the advantages and beneficial effects that:
1. the invention relates to a hydraulic exoskeleton robot control system and a control method for realizing rhythm compliant motion, which simulate the structural characteristics of human motor nervous system layering, and are divided into a motion sensing and gait planning layer and an execution layer servo control system. The motion perception and gait planning layer takes a gait mode generator as a core and receives data of a plantar pressure sensor, a man-machine interaction force sensor, an inertia sensor and a man-machine interaction interface to generate motion curves of all joints. The execution layer takes a hydraulic servo controller as a core, takes a joint reference motion track generated by a gait pattern generator as a given value, takes a joint angle encoder and a joint force sensor as feedback, and simultaneously has joint position control and joint force control algorithms, which form a bottom layer motion closed-loop control system.
2. The invention provides a control system and a method for realizing flexible motion of an exoskeleton robot. On the control system framework, the hierarchical structural characteristics of the human motor nervous system are simulated, a hierarchical and distributed control system is provided, and the real-time performance and the reliability of the system are improved by reasonably distributing the calculated amount of each link; in the control strategy, a higher-level gait mode controller is introduced on the basis of motion control of the bottom layer of each joint, and the motion tracks of each joint are uniformly coordinated and planned, so that the exoskeleton robot has more flexible, agile and coordinated bionic motion capability. Through the innovation of the hardware architecture and the control strategy of the control system, the overall action flexibility of the exoskeleton man-machine system is improved.
3. The gait pattern generator can have the capacity of on-line learning and adjustment according to the external environment change. The external environment change is reflected to the input of the gait pattern generator through the characteristic variables of the plantar pressure signal, the human-computer interaction force signal and the human posture signal, the synaptic connections among the neuron nuclei in the gait pattern generator are adjusted on line according to a certain learning rule, and the coupling relation among the nuclei is dynamically changed, so that the coupling relation among the joint reference motion tracks is dynamically changed, and the adaptability among human machines is finally improved.
4. The bottom layer position servo control adopts a three-closed-loop control system consisting of joint angles, servo valve openness and hydraulic cylinder pressure, and can greatly improve the steady-state precision and dynamic performance of position control.
Drawings
FIG. 1 is a block diagram of the overall system of the present invention;
FIG. 2 is a block diagram of the motion sensing and gait planning system of the invention;
FIG. 3 is a block diagram of the hydraulic servo control system of the present invention;
FIG. 4 is a schematic diagram of the electro-hydraulic drive system of the present invention;
FIG. 5 is a flow chart of a control method of the executive layer controller of the present invention;
fig. 6 is a block diagram of the power supply system of the present invention.
Detailed Description
The embodiments of the invention will be described in further detail below with reference to the accompanying drawings:
biological studies suggest that rhythmic movement in humans and animals is produced by Central Pattern Generators (CPGs) located in the spinal cord. The central pattern generator CPG is a local oscillation network formed by middle neurons, realizes self-oscillation through mutual coupling among the neurons, generates multi-path or single-path periodic signals with stable phase interlocking relation, and coordinates and controls the rhythmic motion of limbs or related parts of the body. The invention provides a hydraulic exoskeleton robot control system and a control method for realizing rhythmic compliant motion.
A hydraulic exoskeleton robot control system for realizing rhythmic compliant motion is shown in figure 1 and comprises a sensing and planning system, a servo control system and a power supply system;
the perception and planning system comprises a perception and planning processor, a plantar pressure acquisition module, a man-machine interaction force acquisition module, an inertial sensor module and a man-machine interaction interface; the output end of the plantar pressure acquisition module is connected with the perception and planning processor and is used for measuring the distribution of plantar pressure in time and space; the output end of the human-computer interaction force acquisition module is connected with the perception and planning processor and is used for measuring contact force information between the thigh and the exoskeleton of the wearer; the output end of the inertial sensor data acquisition module is connected with the perception and planning processor and is used for measuring the posture information of the lower limbs, the small limbs and the upper limbs of the wearer; the human-computer interaction interface and the perception and planning processor are connected and used for capturing, transmitting and displaying human-computer data interaction; the perception and planning processor comprises a DSP processing module and an FPGA interface module, the output end of the perception and planning processor is connected with the servo control system and used for receiving the output data of each acquisition module, carrying out online comprehensive analysis on the human motion gait, generating the motion reference track and the control mode of each joint of the robot on line and outputting the reference track and the control mode to the servo control system;
the servo control system comprises an execution layer controller, an electro-hydraulic driving system, a feedback measuring unit and a robot body module, wherein the servo control system is shown in FIG. 3; the execution layer controller comprises a DSP processing module and an FPGA interface module; the electro-hydraulic driving system consists of a hydraulic pump motor driving plate, a servo valve motor driving plate and a hydraulic system; the FPGA interface module of the executive layer controller receives data of each sensor in the robot feedback measurement unit and outputs the data to the DSP processing module of the executive layer controller; the output end of the DSP processing module of the execution layer controller is connected with the hydraulic system through a hydraulic pump motor drive board and a servo valve motor drive board and is used for outputting control signals of a hydraulic pump motor and a servo valve motor so as to control the hydraulic system to actuate; the output end of the hydraulic system is connected with the robot body module and used for driving each joint module of the robot body to move; the hip joint and knee joint angle encoder on the robot body is connected with the FPGA interface module of the executive layer controller and used for outputting the hip joint angle and the knee joint angle of the robot body to the FPGA interface module of the executive layer controller for feedback; a hydraulic pump rotating speed encoder, a servo valve angle encoder, a hip cylinder oil pressure sensor and a knee cylinder oil pressure sensor on the hydraulic system are connected with the FPGA interface module of the executive layer controller and are used for outputting a hydraulic pump rotating speed, a servo valve opening degree, a robot hip cylinder pressure signal and a robot knee cylinder pressure signal of the hydraulic system to the FPGA interface module of the executive layer controller for feedback; the hydraulic pump motor and the servo valve motor are connected with the FPGA interface module of the executive layer controller through current sensors and are used for outputting current signals of the hydraulic pump motor and the servo valve motor to the FPGA interface module of the executive layer controller for feedback;
the output end of the power supply system is respectively connected with the sensing and planning system and the servo control system and supplies power to the sensing and planning system and the servo control system;
the general architecture of the hydraulic exoskeleton robot control system for realizing rhythmic compliant motion of the invention is shown in fig. 1, and adopts a distributed structure comprising: the system comprises a top-layer motion perception and gait planning system, a bottom-layer hydraulic servo control system and a power supply system; the composition, the function and the effect of each part are as follows:
and the top-level perception and planning system is responsible for perceiving human action intention and planning out the motion reference track of each joint of the exoskeleton robot in real time.
The structure of the perception and planning system is shown in fig. 2, and the perception and planning system realizes the recognition of the movement intention and the movement gait planning of a wearer and comprises external modules such as a sole pressure acquisition module, a man-machine interaction force acquisition module, an inertial sensor module, a man-machine interaction interface and the like and a perception and planning processor.
The external module sends the sensor information to the main processor for data comprehensive analysis, and a gait pattern generator positioned on the main processor generates reference motion tracks of all joints, wherein:
(1) the plantar pressure acquisition module measures the distribution of plantar pressure in time and space, and then human gait phase sensing is achieved. The sole pressure acquisition module is installed in the left and right sole of ectoskeleton robot, and pressure sensor theory of operation does: the U-shaped air pipe is deformed when being subjected to pressure change, the air pipe is deformed to generate pressure change at the pipe opening, the gas pressure sensor connected with the pipe opening of the air pipe outputs an analog voltage model, and the analog voltage model is subjected to analog filtering, amplification and AD acquisition and sends a digital signal to the main processor through the CAN bus. The analog signal acquisition selects a singlechip based on an ARM framework, the singlechip is provided with at least three on-chip AD interfaces and one CAN interface, the AD sampling frequency is 1KHz, the precision is 12 bits, the singlechip is provided with a digital filtering algorithm, and the CAN communication rate is 100 Hz.
(2) The human-computer interaction force acquisition module is used for measuring contact force information between the thigh of the wearer and the exoskeleton, and further human motion intention perception is achieved. The force measuring principle of the human-computer interaction force sensor is similar to the working principle of a plantar pressure sensor, the pressure sensor measures the pressure change of an air bag at the human-computer contact part, outputs an analog voltage signal, and sends a digital signal to a main processor through analog filtering, amplification and AD acquisition. The analog signal acquisition selects a singlechip based on an ARM framework, the singlechip is provided with at least two paths of on-chip AD and one path of CAN interfaces, the AD sampling frequency is 1KHz, the precision is 12 bits, the singlechip is provided with a digital filtering algorithm, and the CAN communication rate is 100 Hz.
(3) The inertial sensor data acquisition module is used for measuring posture information of the large and small legs of the lower limbs and the trunk of the upper limbs of a wearer and providing reference for human gait planning. The high-precision gyro accelerometer MPU6050 is selected for the inertia sensitive unit, the ARM processor is used for reading the measurement data of the MPU6050, the attitude resolver is arranged in the processor, the attitude information can be accurately output in a dynamic environment by matching with a dynamic Kalman filtering algorithm, the attitude information is sent to the main processor through the Bluetooth interface, and the Bluetooth communication rate is 100 Hz.
(4) The human-computer interaction interface adopts a touch screen, is fixed on the arm of a wearer through a binding band, provides a window for setting related parameters and displaying a system state for the wearer, realizes data interaction through a serial port, and has the serial port transmission rate of 1 KHz.
(5) The main processor is used as a hardware platform for data collection, analysis and processing, and realizes the functions of on-line analysis of human body movement gait, on-line generation of movement tracks of all joints of the robot and the like. The main processor selects a dual-core architecture formed by selecting TI 6748 series DSP and Xilinx Spartan6 series FPGA, and the FPGA and the DSP are communicated through an EMIF bus. The FPGA has the main frequency of 32MHz and is used for expanding a sensor data interface and realizing sensor data filtering. Two CAN interfaces are expanded outside the FPGA, wherein one CAN interface forms a communication network with a plantar pressure acquisition module and a man-machine interaction force acquisition module, the other CAN interface forms a communication network with an execution layer main controller, and the CAN communication rate is 100 Hz; two paths of serial ports are expanded to respectively realize communication with a human-computer interaction interface and an upper computer interface, and the serial port communication rate is 1 KHz; and one path of Bluetooth interface is expanded to realize communication with the inertia acquisition module, and the Bluetooth communication rate is 100 Hz. The DSP main frequency is 456MHz, so that the joint posture resolving function in the gait mode generator is realized, and the reference track and the control mode information of each joint are output.
2. And the bottom servo control system is used as an action execution layer to receive the attitude command sent by the top layer to carry out position control or force control of the bottom layer.
(1) And the execution layer controller is used for realizing real-time data communication with the perception planning system, sensor data acquisition, hydraulic servo control algorithm resolving and sending a control command to the driving unit. The controller adopts a dual-core architecture formed by TMS320F28335 model DSP of TI company and Spartan6 series FPGA of Xilinx company, and the two controllers are communicated through an EMIF bus. The FPGA main frequency is 32MHz, and is used for expanding a sensor interface and filtering a sensor signal, and the FPGA externally expands 6 incremental differential encoder interfaces, 8 AD interfaces and 2 serial ports. The DSP main frequency is 150MHz, the realization of bottom layer position control or force control algorithm is realized, 1 CAN interface is expanded, and 4 PWM control ports are expanded. The input of the controller is the joint track and control mode output by the gait planning subsystem, the controller realizes data transmission through a CAN bus, and the data communication rate is 100 Hz.
(2) The electro-hydraulic driving system is an execution structure of the exoskeleton robot and directly drives the exoskeleton robot joints to act. A set of micro electro-hydraulic driving units are respectively arranged on the left side and the right side of the lower limb of the exoskeleton, and the schematic diagram of the micro electro-hydraulic driving units is shown in figure 4, and the micro electro-hydraulic driving units comprise an oil pressure sensor 1, a safety valve 3, an oil tank 4, a hydraulic pump 5, a knee cylinder actuating servo valve 6, a one-way valve 7, a hip hydraulic cylinder 8, a knee hydraulic cylinder 9 and a hip cylinder actuating servo valve 10. Functionally, the hip and knee cylinders are powered by the same hydraulic pump, and the flow and pressure into the cylinders are regulated by adjusting respective servo valves. In a practical control system, a control strategy combining hydraulic pump control and hydraulic servo valve control is adopted, so that the hydraulic system outputs a position or a torque designated by a controller. The hydraulic pump is driven by a three-phase brushless motor with the rated power of 700W. The servo valve is driven by a direct current brush motor, and the rated power of the motor is 100W.
(3) The exoskeleton robot body mainly comprises an upper limb structure and a lower limb structure. The hip joint and the knee joint of the lower limb have active degrees of freedom, are driven by the micro electro-hydraulic driving system, and the ankle joint has passive degrees of freedom and is driven by the ankle joint of the human body to move. The upper limb structure is mainly a back frame used for bearing and fixing a human body and a heavy object to be borne.
(4) The feedback measuring unit provides state feedback signals required by closed-loop control for the electro-hydraulic driving system and mainly comprises a joint angle encoder, an oil pressure sensor and a current sensor. The joint angle encoder comprises a left hip joint angle encoder, a left knee joint angle encoder, a left hip hydraulic cylinder servo valve motor angle encoder and a left hydraulic cylinder pump-to-motor rotating speed encoder; the device comprises a right hip joint angle encoder, a right knee joint angle encoder, a right hip hydraulic cylinder servo valve motor angle encoder and a right hydraulic cylinder pump-to-motor rotating speed encoder. Wherein the hip joint and knee joint angle encoders adopt 4000-line incremental encoders, output orthogonal pulse signals are quadrupled in an FPGA, and the angle measurement resolution is 0.0225 degrees. The hydraulic servo valve angle encoder adopts a 1000-line incremental encoder, outputs an increased pulse signal in the FPGA for quadruple frequency, and has the angle measurement precision of 0.09 degrees. The hydraulic pump motor rotating speed encoder adopts a 2048-line incremental encoder, outputs orthogonal pulse signals, and has quadruple frequency in the FPGA, and the angle measurement resolution is 0.0439 degrees. The oil pressure sensor comprises a left hip hydraulic cylinder pressure sensor and a left knee hydraulic cylinder pressure sensor; a right hip hydraulic cylinder pressure sensor, a right knee hydraulic cylinder pressure sensor. The oil pressure sensors respectively measure the oil pressure at the side of a rod cavity, a rodless cavity and a knee cylinder rodless cavity of the hip cylinder, a PX600 series pressure sensor manufactured by OMEGA company is selected, the range of an output analog differential signal is 0-10mV, AD sampling is carried out after the output analog differential signal is amplified by an instrumentation amplifier, the AD sampling frequency is 10KHz, and the sampled data enters an FPGA (field programmable gate array) to be subjected to digital filtering. The current sensor selects a linear Hall to measure the current at a direct current bus of the pump-to-motor, the range of the analog signal output by the linear Hall is 0-3.3V, the Hall output is subjected to AD sampling after being filtered, and the AD sampling frequency is 10 KHz.
3. And the power supply system provides a direct current stabilized power supply meeting the power consumption requirement of the system for each module.
The power supply system is shown in fig. 6, the lithium battery module outputs 48V direct current power, 1 path of 48V power, two paths of 12V power and 3 paths of 5V power are generated through the power adapter, power isolation design is performed on a circuit board according to actual application requirements, and power design indexes are shown in table 1.
On the sensing and planning processing board, 4 paths of 5V power supplies are respectively isolated from the input 5V power supply signals and respectively supplied to the plantar pressure acquisition module, the man-machine interaction force acquisition module, the inertial sensor data acquisition module and the man-machine interaction interface module.
On the electro-hydraulic servo control board, 3 paths of power supply isolation are carried out on one path of input 5V power supply signal, and the power supply signal is respectively supplied to a joint angle encoder, a hydraulic pump motor rotating speed encoder and a servo valve angle encoder; and 2 paths of power supply isolation are carried out on the other path of input 5V power supply signal, and the power supply signal is respectively supplied to the linear current Hall sensor and the hydraulic pressure sensor in the hydraulic cylinder.
On the motor power driving board, an input 48V power supply is supplied to a hydraulic pump motor, one path of 12V electric signal is supplied to a brushless motor Hall sensor, and the other path of 12V power supply is supplied to a hydraulic cylinder servo valve.
TABLE 1 Power supply design index
A method for controlling a hydraulic exoskeleton robot to achieve rhythmic compliant motion, as shown in fig. 5, comprises the following steps:
the specific method of the step 1 comprises the following steps: the foot pressure acquisition module and the human-computer interaction force acquisition module respectively send foot pressure information and human-computer interaction force information to the sensing and planning processor through a CAN bus interface, the inertial sensor data acquisition module sends wearer posture information to the sensing and planning processor through a Bluetooth interface, and the human-computer interaction interface sends control parameters (control mode, system rigidity and the like) set by a wearer to the sensing and planning processor through a serial port;
the specific method of the step 2 comprises the following steps: the perception and planning processor carries out filtering and feature extraction on the input plantar pressure signal, the human-computer interaction force signal and the wearer posture signal, and extracts gait phase, stride and gait cycle, interaction force between the wearer and the exoskeleton and feature variables of the wearer posture angle respectively.
the specific steps of the step 3 comprise:
(1) a gait pattern generator is embedded in the perception and planning processor and used for simulating a central pattern generator of a human spinal cord to generate rhythmic motion; the gait pattern generator consists of four functional neuron network nuclei which are coupled with each other, and respectively corresponds to the motion trail generators of the left hip joint, the left knee joint, the right hip joint and the right knee joint to generate reference motion trails of all the joints;
(2) inputting the external sensing signal characteristic variables extracted in the step (2) to a functional neuron network nucleus in a gait pattern generator to serve as external excitation;
(3) and the gait pattern generator performs learning training, the synaptic weights among the neuron network nuclei are continuously updated until the synaptic weights converge to a steady state value, and then the average field potentials output by the four neuron network nuclei are respectively used as reference motion tracks of the left hip joint, the left knee joint, the right hip joint and the right knee joint.
and 5, dividing a control mode into a position control mode and a force control mode, dividing the position control mode into hip joint angular position control and knee joint position control, adopting a control strategy of three closed loops of a joint angle, a servo valve opening and hydraulic cylinder internal oil pressure, nesting three closed loop control systems in sequence, adopting a PID control algorithm for each servo closed loop, and setting control parameters according to the principle of firstly adopting an inner loop and then adopting an outer loop.
The specific steps of the step 5 comprise:
(1) hip joint angular position control: the hip joint angle, the opening of a servo valve and the pressure of a hip hydraulic cylinder are adopted to form a three-closed-loop control system, wherein a pressure sensor in the hip hydraulic cylinder senses the change of the hip load pressure firstly, a pressure closed loop of the hydraulic cylinder is set as an innermost loop, a rotating speed closed loop of a hydraulic pump is used as a second-layer closed loop, and the hip joint angle as a final control target is an outermost control closed loop;
(2) knee joint angular position control: the three-closed-loop control system is formed by knee joint angle, hydraulic servo valve opening degree and knee hydraulic cylinder pressure, wherein a pressure sensor in the knee hydraulic cylinder senses knee load change firstly, so that the knee pressure closed loop is used as the innermost loop of the control system, the outer layer is the servo valve opening degree closed loop, and the outermost layer is the knee joint angle control closed loop.
And 6, performing dynamic modeling on the exoskeleton robot system by using a Lagrange method in a force control mode to obtain expected torque of each joint of the exoskeleton under a given reference track, and acquiring oil pressure in a hydraulic cylinder as feedback to perform force closed-loop control.
In this embodiment, when position or force control is performed, the current of the hydraulic pump-electric motor needs to be collected in real time, a current threshold is set, and when the current exceeds the threshold, an overcurrent protection measure needs to be performed by the control system.
It should be emphasized that the examples described herein are illustrative and not restrictive, and thus the present invention includes, but is not limited to, those examples described in this detailed description, as well as other embodiments that can be derived from the teachings of the present invention by those skilled in the art and that are within the scope of the present invention.
Claims (6)
1. A hydraulic exoskeleton robot control system for realizing rhythmic compliant motion is characterized in that: the system comprises a sensing and planning system, a servo control system and a power supply system;
the sensing and planning system comprises a sensing and planning processor, a plantar pressure acquisition module, a man-machine interaction force acquisition module, an inertial sensor data acquisition module and a man-machine interaction interface; the output end of the plantar pressure acquisition module is connected with the perception and planning processor and is used for measuring the distribution of plantar pressure in time and space; the output end of the human-computer interaction force acquisition module is connected with the perception and planning processor and is used for measuring contact force information between the thigh and the exoskeleton of the wearer; the output end of the inertial sensor data acquisition module is connected with the perception and planning processor and is used for measuring the posture information of the lower limbs, the small limbs and the upper limbs of the wearer; the human-computer interaction interface and the perception and planning processor are connected and used for capturing, transmitting and displaying human-computer data interaction; the perception and planning processor comprises a DSP processing module and an FPGA interface module, the output end of the perception and planning processor is connected with the servo control system and used for receiving the output data of each acquisition module, carrying out online comprehensive analysis on the human motion gait, generating the motion reference track and the control mode of each joint of the robot on line and outputting the reference track and the control mode to the servo control system;
the servo control system comprises an executive layer controller, an electro-hydraulic driving system, a feedback measuring unit and a robot body module; the execution layer controller comprises a DSP processing module and an FPGA interface module; the electro-hydraulic driving system consists of a hydraulic pump motor driving plate, a servo valve motor driving plate and a hydraulic system; the FPGA interface module of the executive layer controller receives data of each sensor in the robot feedback measurement unit and outputs the data to the DSP processing module of the executive layer controller; the output end of the DSP processing module of the execution layer controller is connected with the hydraulic system through a hydraulic pump motor drive board and a servo valve motor drive board and is used for outputting control signals of a hydraulic pump motor and a servo valve motor so as to control the hydraulic system to actuate; the output end of the hydraulic system is connected with the robot body module and used for driving each joint module of the robot body to move; the hip joint and knee joint angle encoder on the robot body is connected with the FPGA interface module of the executive layer controller and used for outputting the hip joint angle and the knee joint angle of the robot body to the FPGA interface module of the executive layer controller for feedback; a hydraulic pump rotating speed encoder, a servo valve angle encoder, a hip cylinder oil pressure sensor and a knee cylinder oil pressure sensor on the hydraulic system are connected with the FPGA interface module of the executive layer controller and are used for outputting a hydraulic pump rotating speed, a servo valve opening degree, a robot hip cylinder pressure signal and a robot knee cylinder pressure signal of the hydraulic system to the FPGA interface module of the executive layer controller for feedback; the hydraulic pump motor and the servo valve motor are connected with the FPGA interface module of the executive layer controller through current sensors and are used for outputting current signals of the hydraulic pump motor and the servo valve motor to the FPGA interface module of the executive layer controller for feedback;
and the output end of the power supply system is respectively connected with the sensing and planning system and the servo control system and supplies power to the sensing and planning system and the servo control system.
2. The method of controlling a hydraulic exoskeleton robot control system that achieves rhythmic compliant motion as recited in claim 1 in which: the method comprises the following steps:
step 1, a sensing and planning processor receives an input signal of an external sensor;
step 2, a perception and planning processor extracts the characteristics of the signals acquired in the step 1;
step 3, generating a motion reference track of each joint of the robot body by a gait pattern generator in the perception and planning processor;
step 4, taking the reference track and the control mode of each joint given by the sensing and planning system in the step 3 as the input of a servo control system;
step 5, dividing a control mode into a position control mode and a force control mode, dividing the position control mode into hip joint angular position control and knee joint position control, adopting a control strategy of three closed loops of a joint angle, a servo valve opening and hydraulic cylinder internal oil pressure, nesting three closed loop control systems in sequence, adopting a PID control algorithm for each servo closed loop, and setting control parameters according to the principle of firstly adopting an inner loop and then adopting an outer loop;
and 6, performing dynamic modeling on the exoskeleton robot system by using a Lagrange method in a force control mode to obtain expected torque of each joint of the exoskeleton under a given reference track, and acquiring oil pressure in a hydraulic cylinder as feedback to perform force closed-loop control.
3. The method for controlling a hydraulic exoskeleton robot control system for achieving rhythmic compliant motion as claimed in claim 2, wherein: the specific method of the step 1 comprises the following steps: the plantar pressure acquisition module and the human-computer interaction force acquisition module respectively send plantar pressure information and human-computer interaction force information to the perception and planning processor through a CAN bus interface, the inertial sensor data acquisition module sends wearer posture information to the perception and planning processor through a Bluetooth interface, and the human-computer interaction interface sends control parameters set by the wearer to the perception and planning processor through a serial port.
4. The method for controlling a hydraulic exoskeleton robot control system for achieving rhythmic compliant motion as claimed in claim 2, wherein: the specific method of the step 2 comprises the following steps: the perception and planning processor carries out filtering and feature extraction on the input plantar pressure signal, the human-computer interaction force signal and the wearer posture signal, and extracts gait phase, stride and gait cycle, interaction force between the wearer and the exoskeleton and feature variables of the wearer posture angle respectively.
5. The method for controlling a hydraulic exoskeleton robot control system for achieving rhythmic compliant motion as claimed in claim 2, wherein: the specific steps of the step 3 comprise:
(1) constructing a gait pattern generator in a perception and planning processor, wherein the gait pattern generator consists of four functional neuron network nuclei which are mutually coupled and respectively corresponds to a left hip joint, a left knee joint, a right hip joint and a right knee joint motion trail generation unit;
(2) inputting the external sensing signal characteristic variables extracted in the step (2) to a functional neuron network nucleus in a gait pattern generator to serve as external excitation;
(3) and the gait pattern generator performs learning training, the synaptic weights among the neuron network nuclei are continuously updated until the synaptic weights converge to a steady state value, and then the average field potentials output by the four neuron network nuclei are respectively used as reference motion tracks of the left hip joint, the left knee joint, the right hip joint and the right knee joint.
6. The method for controlling a hydraulic exoskeleton robot control system for achieving rhythmic compliant motion as claimed in claim 2, wherein: the specific steps of the step 5 comprise:
(1) hip joint angular position control: the hip joint angle, the opening of a servo valve and the pressure of a hip hydraulic cylinder are adopted to form a three-closed-loop control system, wherein a pressure sensor in the hip hydraulic cylinder senses the change of the hip load pressure firstly, a pressure closed loop of the hydraulic cylinder is set as an innermost loop, a rotating speed closed loop of a hydraulic pump is used as a second-layer closed loop, and the hip joint angle as a final control target is an outermost control closed loop;
(2) knee joint angular position control: the three-closed-loop control system is formed by knee joint angle, hydraulic servo valve opening and knee hydraulic cylinder pressure, wherein a pressure sensor in the knee hydraulic cylinder senses knee load change firstly, so that the knee pressure closed loop is used as the innermost loop of the control system; the outer layer is a servo valve opening closed loop, and the outermost layer is a knee joint angle control closed loop.
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| CN110030234B (en) * | 2019-04-30 | 2023-01-13 | 北京航空航天大学 | Interactive safety control strategy based on hydraulic compliant driver |
| CN110671374B (en) * | 2019-11-05 | 2021-06-29 | 上海航天控制技术研究所 | Load type exoskeleton hydraulic driving system |
| CN110876622B (en) * | 2019-11-05 | 2022-02-11 | 吉林大学 | Method for testing foot stepping pressure of imitated goat legs |
| CN111267071A (en) * | 2020-02-14 | 2020-06-12 | 上海航天控制技术研究所 | Multi-joint combined control system and method for exoskeleton robot |
| CN112192570B (en) * | 2020-10-09 | 2021-09-28 | 中国船舶重工集团公司第七0七研究所九江分部 | Lower limb joint assistance exoskeleton system sensing and control system and method |
| CN112894766B (en) * | 2020-12-25 | 2022-06-14 | 华南理工大学 | Force position hybrid control method applied to walking ankle joint line driving exoskeleton |
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| CN113608451A (en) * | 2021-07-14 | 2021-11-05 | 迈宝智能科技(苏州)有限公司 | Simulation control platform based on ROS and exoskeleton robot simulation control system |
| CN113771040A (en) * | 2021-09-29 | 2021-12-10 | 北京理工大学 | Control system and method for lower limb exoskeleton robot |
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