Object Manipulation of the Variable Topology Truss system

TL;DR

This paper introduces a hybrid control framework for the Variable Topology Truss system, enabling reliable object manipulation by regulating position and force simultaneously through sensor feedback and static modeling.

Contribution

It presents a novel control strategy that combines force and position regulation for the VTT system, addressing previous gaps in manipulation strategy research.

Findings

The control framework achieves accurate force and position tracking.

Experimental validation on single modules and full system demonstrates effectiveness.

Object manipulation is reliably performed with the proposed method.

Abstract

This paper presents an object manipulation strategy for the Variable Topology Truss (VTT) system, a truss robot that comprises actuated truss members connected by passive spherical joints. Although truss robots were originally proposed as rapidly deployable manipulators, manipulation strategy has not been studied thoroughly. To enable manipulation, we introduce a hybrid control framework that regulates position and force concurrently without explicit decoupling. At the actuator level, each member employs a sensor-based force feedback controller to generate the desired axial forces despite high actuator friction. At the task level, the forces applied at the end-effector nodes are produced by computing the required member forces using a static model of the VTT. We evaluate force-tracking performance through experiments on both a single member module and the full VTT system. Finally, we demonstrate object manipulation using two representative configurations and quantitatively assess combined position and force tracking performance. Experimental results confirm that the proposed approach enables consistent and reliable object manipulation with the VTT system.