Abstract:

Aiming at the flexure parallel Stewart platform six-axis force/torque sensor elastic structure composed of flexure hinges, a precise method for the force mapping analytical modeling between six-axis external force and axial tension or compression of each flexure force-measuring branch of flexure integrated parallel six-axis force/torque sensor is proposed. Based on virtual work principle and geometric compatibility condition, and according to the spatial compliance matrix of flexure hinges, the compliance matrix of flexure series branch end of sensor and the whole stiffness matrix of sensor are constructed. The analytical mapping relationship between the six-axis external force and the axial tension or compression of each flexure branch rod of sensor is derived and obtained. The simulation verification of theoretical derivation process mentioned above is carried out by actual example and finite element model of sensor. The results show that the theoretical values and simulated values are consistent, the maximum error is within 7%, which states the force mapping analytical relationship proposed has higher precision, and lays a theoretical foundation for the size optimization design of flexure parallel six-axis force/torque sensor.

Key words: compliance matrix, force mapping, parallel structure, stiffness modeling, six-axis force/torque sensor