Design Of Multi-DOF Lower Extremity Exoskeleton Control System Based On ARM And FPGA

Lower limb exoskeleton robot is a kind of man-machine integrated intelligent equipment for enhancing the movement of wearers.With the development of the electronic information technology,it has become a hot research topic domestically and internationally.Although the overseas research of exoskeleton has made great progress and gradually began to commercialize,its cost is too high,which makes its diffusion in industry difficult.In addition,existing study for the exoskeleton universally has the problems of low degrees of freedom and being unable to implement the function of assistance.Aiming at the deficiency of current research,this paper attempts to develop an exoskeleton robot control system with low cost,small size,high integration,and enough driving freedom.After investigating the movement mechanism of human bodies in detail,this paper proposes a kinematic schema in which the joints of exoskeleton robots match with the joints of human bodies to a greatest extent.Based on the schema,combined with the multi-axis control technology and embedded technology,this study constructs a scheme for the lower limb exoskeleton control system,taking ARM as the main controller and FPGA as the co-controller,as well as adopting SPI bus communication between them.According to the scheme of the exoskeleton control system based on ARM+FPGA,this paper researchs and designs a hardware for the control system.The design of hardware interface circuit about ARM,FPGA minimum system,motor drive amplifier circuit and encoder shaping circuit are completed;Altium Designer is adopted to accomplish the design of the PCB for the control system.The control system software is researched and developed.On the ARM platform,the cross-compilation environment of the embedded Linux system,the migration of the SPI bus drive and the development of the Qt-based application program are accomplished.On the FPGA platform,the PWM waveform generation module,the detection module of the position and speed of the joint motor and the software of the top module are completed,and the PID control algorithm of the joint motor is realized.By using internal clock synchronization mechanism of FPGA,the motion coordination of ten joint motors is realized.The hardware modules of the system are tested,and the function modules of the software are debugged and simulated.Based on language C#,this research develops a monitoring software of the exoskeleton robot control system,and conducts the trajectory tracking experiment,which has excellent results.