Linear Active Disturbance Rejection Anti-Backlash Control for Dual-Motor Coaxial Driving Robotic Joint

This paper describes a linear active disturbance rejection anti-backlash controller for a dual-motor coaxial driving robotic joint. This type of robotic joint is an over-actuated system that dual motors collaboratively drive load each axis. Firstly, a dual-motor driving model is built considering backlash and then a simplified control-orient model is proposed based on the principle of dual-motor anti-backlash strategy. Secondly, a linear active disturbance rejection control-based dual-motor position tracking framework is developed in accordance with the control-orient model. Finally, in order to deal with backlash coupling with unknown external torque, an admittance control-based adaptive position compensator is proposed. Unlike other control strategies, it practically achieves high tracking performance without requiring any backlash and external torque information. The effectiveness and simplicity of proposed control strategy is verified through comparative experiments.