Observability index of identified parameter for kinematic calibration of parallel mechanism

This paper presents a new observability index of identified parameter to quantify the selection of best configuration set in kinematic calibration of parallel mechanisms. This proposed observability index has the following advantages: (1) it is a detailed index for each identified parameters, that is, one index corresponds to one identified parameter; (2) it has a real significance: the variations of estimated value of the identified parameter; (3) it includes the information of both identification Jacobian and measurement noise. Simulation results of a three degrees-of-freedom (DOF) parallel mechanism are given to illustrate the validity and effectiveness of the proposed index.