Development of an Easy-to-Cut Six-Axis Force Sensor

Although the potential demand for force sensors in both robotics and automation is high, the complexity of their structure increases the number of manufacturing processes. As a result, the rising cost of sensors has hindered the practical application of force measurement and force control. In this study, a flexure element is proposed, consisting of a structure that is easier to cut and process than conventional ones. Additionally, holes through the side of a cuboid are incorporated to simplify the manufacturing of force sensors. To ensure the safety of the proposed sensor design, an approximate equation is derived to predict the maximum von Mises stress on the flexure element using design parameters. Subsequently, we clarified a way to attach the strain gauge in a position that improves sensitivity. The results of the actual prototype sensor based on the proposed method show that the maximum nonlinearity error and decoupling error in the other axes are 0.442 %R.O. and 0.660 %R.O., respectively, and the performance is comparable to that of conventional force sensors. Because the prototype has a difference in resolution between the axes, a method for improving the resolution isotropy without changing the difficulty of machining is also proposed. In addition, the validity of the proposed method is demonstrated using experiments. Consequently, a force sensor with the same level of performance was developed using the proposed method, and the cutting process was made easier compared to that of conventional methods. This research is expected to lead to lower cost force sensors in the future.