Measurement model and calibration experiment of new over-constrained and orthogonal parallel six-dimensional force sensor

Abstract

The heavy load multi-dimensional force/torque sensors have become more needed in the fields of aeronautics and astronautics. By introducing redundant load branch, a suitable for heavy load occasions of new over-constrained and orthogonal parallel six dimensional force sensor structures is designed and developed to improve the sensor structure stiffness and bearing capacity, at the same time can effectively restrain the influence of joint friction on the multi-dimensional force sensor measurement accuracy. Based on screw theory, the order static effect coefficient matrixes of the sensor is derived, establish the mathematical model of sensor which under ideal conditions. Considering the initial pre-tightening force and stiffness of measuring branch, based on the static equilibrium equations and displacement compatibility equations, mathematical model for calibration is deduced. The six-dimensional force sensor was manufactured, set the load calibration and signal acquisition and processing experiment system, on the basis of the developed prototype of new over-constrained, orthogonal parallel six dimensional force sensor and the static calibration is performed. To calculate the sensor measurement error matrix, according to the analysis of experimental results obtained measurement accuracy. The study provides reference for the development and application of the overload and over-constrained and orthogonal parallel six-dimensional force sensor.