NIMS-PL: A Cable-Driven Robot With Self-Calibration Capabilities

Abstract

Abstract-We present the Networked InfoMechanical System for Planar Translation, which is a novel two-degree-of-freedom (2-DOF) cable-driven robot with self-calibration and online driftcorrection capabilities. This system is intended for actuated sensing applications in aquatic environments. The actuation redundancy resulting from in-plane translation driven by four cables results in an infinite set of tension distributions, thus requiring realtime computation of optimal tension distributions. To this end, we have implemented a highly efficient, iterative linear programming solver, which requires a very small number of iterations to converge to the optimal value. In addition, two novel self-calibration methods have been developed that leverage the robot's actuation redundancy. The first uses an incremental displacement, or jitter method, whereas the second uses variations in cable tensions to determine end-effector location. We also propose a novel leastsquares drift-detection algorithm, which enables the robot to detect long-term drift. Combined with self-calibration capabilities, this drift-monitoring algorithm enables long-term autonomous operation. To verify the performance of our algorithms, we have performed extensive experiments in simulation and on a real system.

A cable-driven robot for architectural constructions: a visual-guided approach for motion control and path-planning

“…A cable-driven robot with self-calibration for aquatic sensing applications is proposed in Borgstrom et al (2009). This 2 DOF robot was designed for planar translation and it is formed by four cables which means actuation redundancy.…”

“…The kinematics model is obtained by the distribution of cable forces (Borgstrom et al 2009): fully-constrained and under-constrained. The fully-constrained completely determines the position and orientation of the robot as a function of the cables length.…”

Wire Robot Suspension Systems for Wind Tunnels

“…Note, that this implementation cannot be used for realtime control since the worst-case run-time in each control cycle cannot be guaranteed a priori. Several approaches are known to handle this problem (Borgstrom et al, 2009;Bruckmann, Mikelsons, Brandt, Hiller & Schramm, 2008a;Bruckmann et al, 2007b;Bruckmann, Pott, Franitza & Hiller, 2006;Ebert-Uphoff & Voglewede, 2004;Fattah & Agrawal, 2005;Oh & Agrawal, 2005;Verhoeven, 2004). In this application, a force minimizing algorithm for realtime force distribution will be implemented, using a geometric approach (Bruckmann, 2010;Bruckmann et al, 2009;Mikelsons et al, 2008).…”

Rapid Computation of Optimally Safe Tension Distributions for Parallel Cable-Driven Robots

“…This method does not extend to increased degrees of actuation redundancy. Borgstrom et al [11] present a highly efficient LP solver for a four-cable-driven, 2-DOF robot. Other previous work [12]- [14] has also suggested the use of LP methods to compute one-norm minimal tensions distributions.…”

“…In Section V, we demonstrate the computational efficiency of our solution method by providing results from simulated execution of highly dynamic trajectories. In Section VI, we provide experimental results gathered from a real robotic system, i.e., networked infomechanical system for planar translation (NIMS-PL) [11], and in Section VII, we conclude our paper and describe future research thrusts.…”