Robust Control Of Multiple Joint Robot Driven By Ultrasonic Motors

The ultrasonic motor (USM) is a novel motor with completely new structure and new driving principle, which is expected to be used in many important fields. Recently, substantive breakthrough has been accomplished not only in the USM's theory, but also in its design and manufacture technique. What prevents the USM from farther development, today, is that it has not been used in engineering as widely as it is expected. Therefore, it has become one of the most important things to accelerate the industrialization application step of the USM. In order to examine USMs control strategies for the next generation of space robots, this paper developed a multiple joint robot driven by ultrasonic motors and the goals of the robot control are accurate tracking and smooth movement of the robot.Firstly, Virtual Prototyping Technology has been adopted in the design period of the robot. The multi-joint robot has been designed by means of SolidWorks, which is 3D mechanical design software. In order to ensure the performance of the robot, kinematic and kinetic simulation of the robot has been analyzed by means of Adams. The interface of control software has also been designed.Secondly, due to the very quick response of USMs, control strategies of electromagnetic motors are hard to be applied in the robot driven by USMs. Based on the large experiments of position feedback control and velocity feedback control, a velocity-position feedback control system has been proposed. This new control system is a kind of double-loop feedback control, which is on the basis of velocity feedback and assisted with position feedback. Taguchi method has been used to select a set of optimal control parameters and the robust of control has also been analyzed. The actual experiment shows that the control system is effective to achieve the goals of robot control.Finally, based on the combination of fuzzy logical and PID control, a new auto-tuning fuzzy PID control system has been proposed, which can not only ensure higher position accuracy but also keep the robot operating smoothly. The effectiveness of robot control system has been verified by some experimental results.