Kinematic calibration of orthoglide-type mechanisms

TL;DR

This paper introduces a low-cost, practical calibration method for Orthoglide-type mechanisms using simple comparator indicators to measure leg parallelism deviations during motion, enabling effective joint offset estimation.

Contribution

It presents a novel, cost-effective calibration approach based on leg parallelism observations and an algorithm for joint offset estimation in Orthoglide mechanisms.

Findings

Calibration accuracy is validated through experiments.

The method effectively estimates joint offsets.

Sensitivity analysis shows reliable measurement performance.

Abstract

The paper proposes a novel calibration approach for the Orthoglide-type mechanisms based on observations of the manipulator leg parallelism during mo-tions between the prespecified test postures. It employs a low-cost measuring system composed of standard comparator indicators attached to the universal magnetic stands. They are sequentially used for measuring the deviation of the relevant leg location while the manipulator moves the TCP along the Cartesian axes. Using the measured differences, the developed algorithm estimates the joint offsets that are treated as the most essential parameters to be adjusted. The sensitivity of the meas-urement methods and the calibration accuracy are also studied. Experimental re-sults are presented that demonstrate validity of the proposed calibration technique