Analysis of Bilinear Force Tracking Control for Robot Manipulators Under Unknown Environment

This paper presents the analysis of bilinear force/position control (BFC) schemes for the guaranteed force tracking performance of a robot manipulator under unknown environment. Borrowing the concept of impedance force control and hybrid force control, BFC schemes are formulated by combining two force control algorithms. The proposed BFC scheme guarantees the desired force/position tracking performance for any environment with the help of a model-based control method by achieving independent axis control. Guaranteed force tracking control performances of three different bilinear functions are presented and analysed. Their performances are tested and compared without knowing any information on the environment such as position and stiffness a priori. Simulation studies of BFC tracking performances for a robot manipulator to follow the sinusoidal trajectory while regulating a desired force on the environment are performed to verify the practical force tracking control performance.