Design and Optimal Control of Under-Actuated Cable-Driven Micro-Macro Robots

Abstract

In this paper, a new model of a planar underactuated Cable-Driven Micro Macro Robot (u-CDMMR) is presented. The system consists of a Cable-Suspended Parallel Robot (CSPR) whose end-effector is a two-link passive serial manipulator. The system is conceived for applications requiring point-to-point motions inside large workspaces and aims at increasing the versatility of CSPRs. The kinematic and dynamic models are presented and the differential flatness framework is applied to make the system controllable for point-to-point movements. A multi-objective optimization framework for the design of u-CDMMRs is proposed. Once the target movements are defined, a multi-objective optimization is applied to minimize two conflicting objective functions: the movement time and the control effort. The objective functions are evaluated using the optimal trajectory obtained applying a time-energy optimal control. This novel approach allows designer to infer useful information about the influence of the design parameters on the dynamic performance of the system.