Fig. 3

The simulated foot model for validation tests of our measurement system. a & b The simulated model was designed to rotate around the bearing seat. c & d The movable range was set and calibrated as 0° to 70°, in a range similar to the real foot available range. The resting position (about 40° elevation from the platform) is defined as 0° of the model. e We attached a commercial gyro along with our device to record the angular velocity simultaneously. f Test of the feasibility of R1 and R2 estimation by the displacement and resistance signals of QMTA device