A Tension Distribution Method with Improved Computational Efficiency

Abstract

This paper introduces a real-time capable tension distribution algorithm for n degree-of-freedom cable-driven parallel robots (CDPR) actuated by n+2 cables. It is based on geometric considerations applied to the two-dimensional convex polytope of feasible cable tension distribution. This polytope is defined as the intersection between the set of inequality constraints on the cable tension values and the affine space of tension solutions to the mobile platform static or dynamic equilibrium. The algorithm proposed in this paper is dedicated to n degree-of-freedom CDPR actuated by n + 2 cables. Indeed, it takes advantage of the two-dimensional nature of the corresponding feasible tension distribution convex polytope to improve the computational efficiency of a tension distribution strategy proposed elsewhere. The fast computation of the polytope vertices and of its barycenter made us successfully validate the real-time compatibility of the presented algorithm.

Cable Force-Balancing Distribution of the Cable-Driven Parallel Mechanism for Actuator Saturation Avoidance

“…Thus, every cable tensile force of the CDPM should always be kept positive in order for the CDPM to be properly operational. Indeed, the optimization problem for the cable force distribution of the CDPM should be defined by an appropriate objective function subject to inequality conditions to secure that every cable force is kept within the range, between the minimum and maximum tensile cable forces [1][2][3][4][5]. Recently, the pseudoinverse solution equation for the redundantly actuated PM with one redundant actuation is interpreted as line equations.…”

A Survey of Cable-Suspended Parallel Robots and their Applications in Architecture and Construction

“…CSPRs have potential advantages in fullscale on-site construction as compared to conventional serial, aerial or solid linked parallel robots. These include the support for large workspace volumes encompassing entire construction sites with handling of large loads with low robot weight and fast process speeds (Lamaury and Gouttefarde, 2013;Sousa et al, 2016). Critical issues for the implementation of CSPRs on construction sites include complexities in cable robot kinematics, the trade-off between redundancy and cable interference (mostly in fully-constrained systems), the ability to rapidly model and implement ad-hoc arrangements of winch points and the potential for environment disturbance in under-constrained CSPRs.…”

On the analysis of large-dimension reconfigurable suspended cable-driven parallel robots

“…In fact, the continuity of the tension based performance indices can be dealt with by using tension distribution method such as the one in [21]. However, it is difficult to address the second issue since there are different types of constraints including wrench feasibility (continuous nonlinear constraints) and cable interferences (non-differentiable constraints).…”