An Optimization-Based Impedance Approach for Robot Force Regulation with Prescribed Force Limits

Abstract

An optimization based approach for the regulation of excessive or insufficient forces at the end-effector level is introduced. The objective is to minimize the interaction force error at the robot end effector, while constraining undesired interaction forces. To that end, a dynamic optimization problem (DOP) is formulated considering a dynamic robot impedance model. Penalty functions are considered in the DOP to handle the constraints on the interaction force. The optimization problem is online solved through the gradient flow approach. Convergence properties are presented and the stability is drawn when the force limits are considered in the analysis. The effectiveness of our proposal is validated via experimental results for a robotic grasping task.

A Family of Hyperbolic-Type Explicit Force Regulators with Active Velocity Damping for Robot Manipulators

“…The stability analysis is performed in Lyapunov sense; in order to obtain asymptotic stability, LaSalle's theorem is used and experimental results on a two-degree-of-freedom robot are presented. In [39], an optimization-based approach for the regulation of excessive or insufficient forces at the endeffector level is introduced. Their approach minimizes the interaction force error at the robot end-effector and considers the linear impedance model and penalty functions in order to handle the constraints on the interaction forces; stability and convergence properties are analyzed taking into account force limits.…”

Online teaching of robotic arm by human–robot interaction: end effector force/torque sensing

“…A holding pivot point on the end effector and estimating the acceleration of the control point were used to compensate the inertia effect [14]. The interaction force error at the end effector is reduced by using dynamic optimization problem [15]. F/P is transferred from fingertip to 3D space system by using the record and play teaching strategy, and the skill translation between the user and the virtual environment was achieved [16].…”

“…The gripper inertia gives an undesirable effect which is unavoidable. The inertia effect causes a position error during the task execution [14][15][16]21]. The second problem is the rotation of sensor's axes during motion.…”

Compliance Control of a Legged Robot Based on Improved Adaptive Control: Method and Experiments

“…Galvez et al [9] presents a design for feet and ankles with an integrated sensor system to minimize the slippage risk by force optimization schemes. Actually, many other methods have been tried [10]- [12] to solve the control problems such as coupling of force and position, degree of freedom multiplicity, and uncertain posture in mobile robotics. However, current walking robots have only poor ability of leg compliance control to complete complex tasks in an unknown environment.…”