Cable-Driven Parallel Robots (CDPR) have attracted significant research interest for applications ranging from cable-suspended camera applications to rehabilitation and home assistance devices. Most of the intended applications of CDPR involve direct interaction with humans where safety is a key issue. Accordingly, this paper addresses the safety of CDPRs in proposing a strategy to minimize the consequences of cable failures. The proposed strategy consists of detecting a cable failure and avoiding any consequent motion of the end-effector. This is obtained by generating a wrench that is opposite to the direction of the ongoing motion so that the end-effector can reach a safe position. A general formulation is outlined as well as a specific case study referring to the LAWEX (LARM Wire-driven EXercising device), which has been designed within the AGEWELL project for limb rehabilitation. Real-time calculation is carried out for identifying feasible cable tensions, which generate a motion that provides the desired braking force. Simulations are carried out to prove the feasibility and effectiveness of the strategy outlined here in cases of cable failure.
The use of cable-driven parallel robots (CDPR) in real-world applications makes safety a major concern for these devices and a relevant research topic. Cable-suspended camera systems are among the earliest and most common applications of CDPRs. In this paper, we propose a novel after-failure approach for cable-suspended camera systems. This strategy, which is applied after a cable breaks, seeks to drive the end effector, i.e., the camera, toward a safe pose, following an oscillatory trajectory that guarantees positive and bounded tensions in the remaining cables. The safe landing location is optimized to minimize the trajectory time while avoiding collisions with the physical boundaries of the workspace. Results of numerical simulations indicate the feasibility of the proposed approach.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.