Lie Group-Based User Motion Refinement Control for Teleoperation of a Constrained Robot Arm

In unilateral teleoperation systems, robots often face challenges when performing tasks with specific geometric con- straints. These constraints restrict the robot’s movements to certain directions, requiring accurate control of its position and orienta- tion. If the operator’s commands do not consider these constraints, excessive contact force may occur, potentially damaging the robot and its environment. Such scenarios can also trigger frequent emer- gency stops, even with conventional admittance control. To mitigate these issues, we propose a new teleoperation framework tailored for handling geometric constraints. This framework comprises two main components. 1) Geometric Constraint Identification: We use a straightforward line regression method based on Lie group theory to identify geometric constraints. 2) Motion Command Reshaping: The operator’s motion commands are safely recalculated using a projection filter coupled with a Lie group setpoint controller. This approach ensures that the robot’s movements strictly conform to the identified geometric constraints. As a result, this approach significantly reduces the interaction forces and prevents the risk of severe failures or accidents.