Self-calibration of joint offsets for humanoid robots using accelerometer measurements

Abstract

Accurate calibration of joint offsets is a crucial requirement for effective kinematic and dynamic control of robots. Such calibration is typically carried out using cumbersome and time-consuming procedures. We propose a technique for joint offset calibration using the measurements from a distributed set of on-board accelerometers. Differently from existing techniques, we do not assume that the accelerometers are perfectly calibrated. The calibration procedure consist in a two steps automatic procedure : the first step calibrates the accelerometer measurements, while the second one computes the optimal joint offsets. The only constraint required for the kinematic chain calibration trajectory is to follow a sequence of static poses or to move under negligible robot acceleration and slow speed. The proposed approach was validated on a position control problem on the iCub humanoid robot.