Elastic Joint Control Using Non-Collocated Fuzzy and Filtering Scheme: A Comparative Assessment

Conventional model-based control strategies are very complex and difficult to synthesize due to high complexity of the dynamics of robots manipulator considering joint elasticity. This paper presents investigations into the development of composite control schemes for trajectory tracking and vibration control of a flexible joint manipulator respectively. To study the effectiveness of the controllers, initially a collocated PD Controller is developed for tip angular position control of a flexible joint manipulator. This is then extended to incorporate a non-collocated Fuzzy Logic Controller and filtering technique for vibration reduction of the flexible joint system. The Butterworth low-pass filter is designed based on the properties of the system. Simulation results of the response of the flexible joint manipulator with the controllers are presented in time and frequency domains. The performances of the composite control schemes are examined in terms of input tracking capability, level of vibration reduction and time response specifications. Finally, a comparative assessment of the control techniques is presented and discussed.