Dynamic Analysis and Motion Simulation of the 3 DOFs Waist Mechanism for Humanoid Robots

Abstract

The paper presents the dynamic analysis and motion simulation of the waist mechanism meant for humanoids. The proposed waist mechanism has a total of 3 DOFs, allowing movements of the robot’s upper trunk around the pitch, roll and yaw axes. Within the dynamic analysis, the decomposition of the waist mechanism is performed and for each link of the mechanism, motion equations are formed. Reactions in the mechanism links are determined by using D’Alembert’s principle and based on those, the equations for calculating of the driving forces are defined. Finally, the dynamic model of the waist mechanism was formed and a motion simulation for several scenarios was performed. Based on the analysis of the results, it was concluded that the waist mechanism requires small driving torques and therefore less and cheaper actuators, which is an important advantage of this solution.