Optimization of throwing motion planning for whole-body humanoid mechanism: Sidearm and maximum distance

Throwing is a rapid coordinated movement with high configuration and actuation redundancies. Based on a previous work, this paper advances a numerical framework that optimizes the throwing motions and generates the associated dynamic features for a whole-body humanoid mechanism. To generate physically feasible throwing motions in a fully predictive manner, rigorous dynamic models, such as actuation, biped balance based on Zero-Moment Point (ZMP), and ground reaction loads, are associated with the constraints. The algorithm outputs include the motion, required actuator torques, release parameters, and object projectile. Realistic human-like motions of sidearm and maximum distance throwing are generated as optimized solutions, which demonstrate valid kinematic and dynamic cause-effect relations. The sidearm throw shows better optimality than the overarm throw in terms of actuator torques under the proposed mechanical model; it is characterized by the unique hand trajectory and effective utilization of torso axial rotation. The maximum distance throw is associated with active movement of the arm and torso with larger ranges of motion; it is the release height and speed that increase accordingly.