A Study On Human-robot Cooperation Control Of Pneumatic Power-Assisted Exoskeleton

As a kind of wearable intelligent mechanical device,the exoskeleton robot could combine the mechanical force with the human's consciousness to form a closed loop human-machine system by measuring the human's movement state and intention.Thus,the human could easily accomplish many difficult tasks under the control of his or her own awareness and the power support of the exoskeleton.Human-machine coordinated motion control algorithm is one of the key technologies to realize the function of exoskeleton.Although sophisticated control technology in modern robotics have been developed,the researchers who develop exoskeleton robots are still struggling with the huge challenge about how to accurately obtain human's motion intention and achieve human-machine coordinated motion control.In this paper,the research object is the powered exoskeleton driven by the pneumatic artificial muscles and the research is focused on the development of human-machine coordinated motion control algorithm.The main work includes the following several aspects:Firstly,the human-machine interaction interface scheme and the control system based on PC and FPGA board had been established according to the functional demand of system and the movement characteristics analysis of the human limbs.Secondly,this paper had established the joint torque estimation model to obtain the movement intention of human's upper limb,which was based on the musculoskeletal model.The model could combine the joint angular position signal and sEMG signal to achieve the joint torque estimation.Then,the control method based on the torque estimation had been proposed to achieve the human-machine cooperation and power support for the continuous joint flexion and extension movement of upper limb.Thirdly,the joint movement intention of human was divided into two classes:motion mode and stationary mode.Then,this paper proposed the control method based on the support vector machine to maintain joint posture.The experiments shown that the proposed method could make up for the defect that the human couldn't maintain the arm stationary well with power support of the exoskeleton,when only joint torque estimation method was used to judge the motion intention of the operator.Finally,in order to achieve the human-machine cooperation of lower extremity,this paper had established the gait phase detection algorithm based on the finite state machine.The algorithm could combine the joint angular displacement signal and plantar pressure signal to judge current gait phase.Then,this paper proposed the control scheme based on gait phase detection to achieve the human-machine cooperation movement of lower extremity.The walking experiments verify the effectiveness of the control scheme.