An Active Stabilizer for Cable-Driven Parallel Robot Vibration Damping

Abstract

Cable-Driven Parallel Robots (CDPRs) can execute fast motions across a large workspace. However, these performances are reached at the cost of a relatively low stiffness which often yields parasitic vibrations at the CDPR mobile platform. In this paper, vibration damping of CDPRs is addressed by means of an original active stabilizer consisting of actuated rotating arms installed on-board the CDPR mobile platform. A control strategy for the whole system, which consists of the CDPR and the stabilizer, and with one purpose for eachposition control for the platform and vibration damping for the stabilizer-is designed. The system being controlled at two different time scales, the singular perturbation theory can be used to prove the stability of the corresponding closed-loop system. The efficiency of the proposed device and control strategy is tested in simulations in the case of a planar 3-DOF CDPR equipped with a three-arm stabilizer.

Modeling and control of robotic manipulators equipped with the flexible cable-pulley based gravity compensation mechanism

“…Note that if the high-frequency content of the elastic cables is neglected, the mechanism will experience more vibrations and hence its accuracy in the higher speeds maneuvers will decrease. For this reason, the elastic feature of the cables should be considered both in the modeling and the controller design (Khosravi and Taghirad, 2014; Lesellier et al, 2018; Tang et al, 2021; Yuan et al, 2017). However, most of the researches, in the field of cable robots, do not consider the flexibility effects of the cables.…”

Dynamic modelling and vibration suppression of a single-link flexible manipulator with two cables

“…Among various studies related to CDPMs, e.g. [30,31], a number of previous works dealt with the vibration analysis and suppression of CDPMs [32][33][34][35][36][37][38][39]. The dynamic stiffness matrix method is proposed in [33] to perform vibration analysis of CDPMs, which includes the dynamic characteristics of cables considering their masses.…”

“…The dynamic stiffness matrix method is proposed in [33] to perform vibration analysis of CDPMs, which includes the dynamic characteristics of cables considering their masses. Cuvillon et al presented an active vibration damping method for CDPMs in frequency domain [34,35]. Position control method is applied on winches to achieve dynamic control of a CDPM with elastic cables in [37].…”

A Bounding Volume of the Cable Span for Fast Collision Avoidance Verification

“…Several techniques can be used to damp these vibrations: input shaping [1], modal space control [2], or active damping by creating a transient wrench to compensate the vibrations. This wrench can be created by additional actuated stabilizing mechanical devices placed on board the mobile platform [3][4][5][6]. In reference [5], a stabilizer consisting of rotating arms is located on-board the CDPR mobile platform to actively damp vibrations, as illustrated in Figure 1.…”

“…This wrench can be created by additional actuated stabilizing mechanical devices placed on board the mobile platform [3][4][5][6]. In reference [5], a stabilizer consisting of rotating arms is located on-board the CDPR mobile platform to actively damp vibrations, as illustrated in Figure 1. The work reported in the present paper is part of a project aiming to embed a similar stabilizer on the platform of the 6 Degree-of-Freedom (DOF) CDPR CoGiRo [7], shown in Figure 2.…”