Strain Analysis of Six-Axis Force/Torque Sensors Based on Analytical Method (original) (raw)

2017, IEEE Sensors Journal

Reasonable stress and strain distribution are essential for the design of six-axis force/torque sensors. In order to improve the strain distribution, the specific parameters which affect stress and strain distribution need to be found. The numerical solutions of stress and strain on the elastic beam of six-axis force/torque sensors can be quickly obtained by finite element analysis simulation tool, such as ANSYS, but the specific parameters which affect stress and strain distribution cannot be achieved. In this paper, a novel six-axis force/torque sensor scheme with small size and cross beam structure was presented. Then, the mechanical model and analytic equations based on Timoshenko beam theory were established to obtain the analytical solutions of strain. The comparison shows that the analytical solutions and numerical solutions are in good agreement, which indicates that the analytical method is feasible. Finally, the main parameters which affect the strain value and the measure accuracy were analyzed. The analysis results show that the design of six-axis force/torque sensors with cross beam structure can be optimized according to the parameters that affect the stress and strain distribution, if sufficient restrictions are offered. Index Terms-Six-axis force/torque sensors, Timoshenko beam theory, strain analysis, analytical and numerical solutions, optimal solution of structure. I. INTRODUCTION A CQUISITION of multi-dimensional force information is one of the most important senses for intelligent robots. Six-axis force/torque sensors can detect the full force information of three-dimensional space of the robot simultaneously, i.e., three force components: Fx, Fy, Fz and three torque components:Mx, My, Mz of three spatial coordinate axes. As a result, they are the essential parts to improve the intelligence and manipulative level of robots [1]. Such sensors are now widely used for force/torque senses of robots control in various occasions, such as zero force teaching [2], automatic flexible assembly [3], robots multi-hand cooperation [4], robot teleoperation system [5], [6], robotic surgery and rehabilitation training [7], etc.