Design And Experimental Research On Orthogonal-Parallel Six-Axis Force Sensor

The sensor technology occupies more and more important position gradually in development as the accelerating process of high-tech industry intelligenting. As one kind of sensor which is able to detect the information of all force information in space, the sixaxis force sensor has wide applied to robot technology, bio-medical, aerospace, automobile manufacture and other fields. A kind of orthogonal parallel six-axis force sensor with horizontal and vertical branches is proposed in paper. The deeply analysis and research are made for its mechanisms theory, optimizing of structural parameters and static calibration experiment. The main content of concrete research work includes:1)The orthogonal parallel six-axis force sensor of two structures with six or eight branches are proposed. The screw theory is applied to establish the mathematical models of the two kinds of six-axis force sensor. The statics equation is derived and the equation is solved. The mapping relation of the space six-axis external force which imposed by the orthogonal parallel six-axis force sensor to measurement branch axial force is obtained.2)According to isotropy concept, the structure performance of orthogonal parallel six-axis force sensor's two structures is analyzed. Facing to the measurement requirement of six-axis force sensor in practical application, the working condition function model of parallel six-axis force sensor is proposed. According to the working condition function model, with the measurement branch min-range is taken as the optimization target,the structure parameters optimization method of parallel six-axis force sensor is deduced. Using the application of six branches orthogonal parallel six-axis force sensor in surface dress operation as an example, the structure is optimized according to the working condition function model, the min-range of measurement branch and the corresponding structure parameters of sensor are obtained.3) One kind of loading method of orthogonal parallel sensor online static calibration is proposed. The calculation method of six-axis force sensor linearity is derived. The static calibration software is designed and developed by Lab VIEW, which realizes the function of data acquisition and least-squares processing and six-axis force real-time measurement and display in calibration process.4)Based on the research above, the prototype of six branches orthogonal parallel six-axis force sensor is processed. The sensor online static calibration system is put up and the static calibration test is performed. The calibration matrix of six branches orthogonal parallel six-axis force sensor prototype is obtained. The measurement performance of prototype is analyzed, and the linearity matrix of prototype in actual measurement is obtained finally. The experimental results provide the basis for evaluation of prototype measurement precision.