Investigation on Dynamic Modeling of SURENA III Humanoid Robot with Heel-Off and Heel-Strike Motions

Abstract

The understudy SURENA III humanoid robot was designed and fabricated at the Center of Advanced Systems and Technologies (CAST) located in the University of Tehran. In this paper, a full dynamic model of SURENA III in different walking phases including heel-off and heel-strike motions is presented. To this end, first a trajectory planning method based on robot kinematics is introduced. Then, the multi-body dynamics of the robot links are calculated using Lagrange and Kane approaches which are then verified. In this model, the power transmission system is considered to be ideal. Afterward, system identification routine is adopted to model the dynamic behavior of the power transmission system. By adding the calculated actuating torques obtained from analytical model to the required torques for the drive system, the whole dynamic model of the humanoid robot is computed. Comparing the simulation results and experimental results of SURENA III for different types of gaits, the presented dynamic model is verified. Finally, these gaits are studied from several points of view, including joint energy consumption, range of motion (RoM) and maximum velocity, torque and power. It is shown that by adding heel-off and heel-strike motions to the gait 7.34 and 13.95% less energy is consumed, respectively. Also, the heel-off motion improves the gait performance in terms of ankle energy consumption, RoM and velocity, while the heel-strike motion enhances the gait functionality in terms of knee and hip energy consumption and velocity.