In-vivo tension calibration in tendon-driven manipulators

US8412378B2 · kind B2 · utility

Assignees

• GM GLOBAL TECHNOLOGY OPERATIONS LLC · US
• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Muhammad E. Abdallah · Houston, US
• Robert Platt · Houston, US

Key dates

• Filing date: Dec 2, 2009
• Grant date: Apr 2, 2013
• Expiry date: Sep 3, 2031

Classification

• Technology area (CPC G): Physics
• CPC primary: G05B2219/39457
• WIPO field: Handling
• WIPO sector: Mechanical engineering

Abstract

A method for calibrating tension sensors on tendons in a tendon-driven manipulator without disassembling the manipulator and without external force references. The method calibrates the tensions against each other to produce results that are kinematically consistent. The results might not be absolutely accurate, however, they are optimized with respect to an initial or nominal calibration. The method includes causing the tendons to be slack and recording the sensor values from sensors that measure the tension on the tendons. The method further includes tensioning the tendons with the manipulator positioned so that it is not in contact with any obstacle or joint limit and again recording the sensor values. The method then performs a regression process to determine the sensor parameters that both satisfy a zero-torque constraint on the manipulator and minimize the error with respect to nominal calibration values.