Design-to-Workspace Synthesis of a Cable Robot Used in Legs Training Machine

Abstract

Summary This paper deals with a continuous design task of a planar cable robot used in a gait training machine called the cable-driven legs trainer. The design of cable robots requires satisfying two constraints, that is, tensions in the cables must remain non-negative, and cable interferences should be avoided. The carried design approach is based on interval analysis, which is one of the most efficient methods to obtain certified results. The constraints of non-negative tensions and cable to end-effector interference are solved using interval analysis tools. By means of a dynamic simulation, the reached workspace and the produced wrenches of the cable robot are evaluated as a set of interval vectors. An optimization algorithm is then designed to optimize the cable robot structure for the gait training machine. The robot is designed to produce non-negative tensions in the cables and to avoid collision at all times within the desired workspace and under the required external loads.

Stability Analysis of a Reconfigurable and Mobile Cable-Driven Parallel Robot

“…Inverse kinematics, static equilibrium, dynamics, stiffness, and the workspace of CDPR were investigated in [4], [5]. Interval analysis and cable interference were taken into account in [6] to synthesize the workspace of cable-driven leg training in a gait training machine. The workspace boundaries, leading to the definition of wrenchclosure workspace, are numerically determined in [7] which allows the designers to decide whether a pose is acceptable.…”

Analysis and multi-objective optimal design of a planar differentially driven cable parallel robot

“…The geometry of the proposed CPR is determined through multi-objective optimal design for the largest workspace and the highest stiffness magnitude using the genetic algorithm. The multi-objective optimal design adopted in this paper gives more potential useful solutions compared with the commonly adopted optimal design approaches in parallel robots which convert the multiple objectives to a single function [18]. In the end, various performance indices are used to evaluate the proposed robot by comparing with a fully actuated CPR to show the effects of using cable-and-pulley differentials in all aspects.…”