Position Control of 2R Underactuated Robot

Based on Fuzzy Control

FANG Daoxing  YU Yueqing  CHEN Wei

(College of Mechanical Engineering & Applied Electronics Technology, Beijing University of Technology, Beijing 100022 )

Abstract: Based on fuzzy control theory, the joints position control of 2R underactuated robot is studyed. a electromagnetic brake is fixed into the passive joint to control the coupling state between joints. The process to control the robot position can be divided into two phases. The brake is released during the first phase. Depending on the dynamic coupling effect between the angle acceleration of passive joint and the torque of active joint, passive joint can be controlled indirectlly to the desired position along the desired trajectory. The fuzzy control rules during the first phase are described and fuzzy controller are designed to control the motion of passive joint. The brake is locked during the second phase, then active joint is controlled to the desired position. The experimental control system based on PMAC controller is designed and developped. Finally, the position control of the 2R underactuated robot is achieved successfully by experiments. The experimental data indicates that the fuzzy control method presented has high precision and good robust character for position control of the passive joints. Furthermore, this method doesn’t rely on the dynamic modle of the robot and the calculation during real-time control is very few, which shows the advantage of intelligent control.

Key words: Underactuated robot  Fuzzy control  Position control  Control system

CLC No: TP24

国家自然科学基金(50575002)、北京市自然科学基金(3062004)和北京市人才强教计划资助项目. Received 20070125, received in revised form 20070920