Design of Force Sensors of Rehabilitation Robot for Knee Rehabilitation

Abstract

This paper describes the design and fabrication of a one-axis force sensor and two-axis force sensors with parallel plate beams (PPBs) for measuring forces in a knee rehabilitation exercise using a lower rehabilitation robot. The two-axis force sensors are composed of a Fx force sensor and a Fz force sensor, and they detect the x and z directional forces, respectively. The two-axis force sensors and one-axis force sensor were designed using the Finite Element Method (FEM), and manufactured using strain-gages. The characteristics experiment of the two-axis force sensors and one-axis force sensor were performed. The test results indicated that the interference error of the two-axis force sensor was less than 1.17%, the repeatability error and the non-linearity of the one-axis force sensor were less than 0.03%, and the repeatability error and the non-linearity of the two-axis force sensors were less than 0.03%.