Kinematic calibration of Orthoglide-type mechanisms from observation of parallel leg motions

TL;DR

This paper introduces a cost-effective calibration method for Orthoglide-type parallel manipulators, using leg parallelism observations to accurately identify joint offsets and improve manipulator precision.

Contribution

It presents a novel calibration approach based on leg parallelism observations and a simple measurement system, enhancing efficiency and accuracy over existing methods.

Findings

The calibration method accurately identifies joint offsets.

Experimental results confirm the method's effectiveness.

Sensitivity analysis shows robustness of the measurement approach.

Abstract

The paper proposes a new calibration method for parallel manipulators that allows efficient identification of the joint offsets using observations of the manipulator leg parallelism with respect to the base surface. The method employs a simple and low-cost measuring system, which evaluates deviation of the leg location during motions that are assumed to preserve the leg parallelism for the nominal values of the manipulator parameters. Using the measured deviations, the developed algorithm estimates the joint offsets that are treated as the most essential parameters to be identified. The validity of the proposed calibration method and efficiency of the developed numerical algorithms are confirmed by experimental results. The sensitivity of the measurement methods and the calibration accuracy are also studied.