Research On Coreless Motor Position Servo Control Oriented Exoskeleton Robot

The past years witnessed the great development in robotics technology whichcontributes to the widely application of robotics in multitudes of fields. Exoskeletonrobot stands out and becomes a current hot topic. Considering comprehensively on theproperties of motors such as simplicity, small volume, light weight, high efficiency andstability, coreless motor is widely employed for the drive of the exoskeleton robots.However, the uncertainty and the parameters and the effect of disturbance on the motorsystem are urgent problems to be solved since they may affect the performance orstability of the robot system. This paper intends to shed some lights on the problems:Study the effect of the parameter uncertainty as well as the effect of disturbance onthe coreless motor based on the analysis of the reasons for parameter uncertainty of thecoreless motor. Further, propose a double loop control method, i.e., position loop andacceleration loop, to achieve position servo control of the coreless motor. On the basisof the elementary structure of the exoskeleton robot and coreless motor drive system,study the mathematical model of the coreless motor on both the three-phase staticcoordinate system and two phase coordinate system which is followed by some work onmotor vector control system and the principle of SVPWM modulation.Design the adaptive backstepping based coreless motor velocity controller andparameter adaptation law which is verified by the stability analysis of the controllers.We simulate the velocity controller under varying parameter and disturbance whoseresult indicates that the controller is capable to drive the system to the desired velocitywith strong disturbance rejection property. From the simulation, conclude theeffectiveness of the proposed scheme.Design an active disturbance rejection control (ADRC) based coreless motorposition controller which is capable to reject the effect of the variation of parameters aswell as the disturbance on the motor. Based on the velocity controller, demonstrate theperformance of the controller by simulation. The result of simulation shows that thecontroller tracks the desired signal well with fast response, high accuracy, robustness under some parameter uncertainty and disturbance which verify the effectiveness of thealgorithm.