Research On Embedded Control System For Upper Limb Exoskeleton Power Assist Robot

Upper limb exoskeleton power assist robot is a kind of new mechatronics wearable device, which can provide the operator with functions like protection, body support, auxiliary movement and so on. Because of the particularity of the services, high performance embedded control system is prominent demanded by the upper limb exoskeleton power assist robot, comparing with general control systems. In this paper, the system solution, software and hardware implementation, and experimental research of the embedded control system are studied.First of all, this paper puts forward a kind of embedded control system solution, which uses microprocessor ARM as upper computer, microcontroller DSP as lower computer, and CAN bus as communication mode, after considering upper limb exoskeleton power assist robot’s special requirements. The upper computer ARM9 responsibles for collecting the operator’s moving signals, combining with the man-machine coordinated control algorithm to get control command and passing it to lower computer DSP. The lower computer DSP responsibles for collecting the angular displacement signals and gas pressure signals, according to the command of the upper computer ARM9 and combining with control algorithm to control the movement of the pneumatic high-speed on-off valves. This project is proved to be feasible through the scheme evaluation, and lays the foundation for the follow-up building of the embedded control system hardware system.Secondly, a set of hardware system is designed, which consists of ARM developed board、ARM extended board、DSP developed board and DSP extended board. Control softwares are porgramed on the ARM platform and DSP platform separately. On the ARM platform, the embedded linux kernel and file system are transplanted, the drivers are designed and the control software based on Qt developed. And on the DSP platform, signals’sampling, controlling of electromagnetic valves, transplanting the sliding mode control algorithm and communicating with upper computer with CAN bus are realized. In addition, serial communication with PC is realized, so that the state variables of the robot can be transmitted to PC in real time during the experiment.Finally, a software based on LabvIEW on PC are designed to monitor the motion state of the robot. A series of experiments are carried out on the prototype system, which include joint-position control experiment, sine curve following experiment and human-machine collaborative experiment. Results of the experiments verified the safety and reliability of the embedded control system. The realization of the system can provide a hardware and software foundation and practice experiences for the following study on lower limb exoskeleton power assist robot.