Design Of Sampling ARM’s Control System

The sample robotic of luna’s surface is used to select surface regolith， thisrobotic arm’s special characteristic is joints flexible, despite the conventional roboticarms’ coupling and nonlinear feature. Based on the5DOF sample robotic arm whichwas made by center of space exploration ministry of education independently， acontrol system of this robotic is designed.First of all, the control system is designed by using the modularization designing.A distributed control system is built based on the CAN protocol, not a conventionalmotion card.Secondly, the kinematic model is established with D-H method and geometricmethod. The ARM’s kinematic model includes the front kinematic model and theinverse kinemic model. The front kinematic model is established by D-H method,while the inverse kinematic model is constructed by geometric method.Thirdly, the nonlinear friction model of the robotic joint is constructed byexperiments. Firstly, the relationships between the non-linear friction and the motor’scurrent and the non-linear friction and the angular acceleration are derived basing onthe established dynamic equations of robotic arm’s joints. Then, the angularacceleration is estimated based on the Kalman-Newton prediction machine which isdesigned through the sampled angle signal. Through the angular acceleration andsampling current, the friction torque is calculated, and an exponential friction modelis established. Finally, basing on the friction model, a feed-forward compensationcontroller is designed to compensate the non-linear friction.Then, the control system’s software and hardware are designed. Based on theconventional robotic arm and the useing experience of the robotic, the hardware isdesigned with motor controller, angle single check, current check and CAN model.Based on the hardware the lower software is designed and the interface of the controlsystem is designed.Lastly, samping and translation experiments are carried out on the1:1landingand jumar clamp model. All of the ideal working condition and limiting conditionexperiments were carried out successfully. All the experiments verify the controlsystem is useful.