Design Optimization for Minimizing Actuation Energy of a Dynamic Tripedal Walking Robot: Revisiting the Double Pendulum

This work presents a systematic approach to the optimal co-design of a multibody dynamical system’s mechanics and control. The formulation presented is based on a simple double pendulum system, thus allowing a focused illustration of the co-design methodology. However, the ultimate goal is to apply this co-design methodology to the design of a novel Self-excited Tripedal Dynamic Experimental Robot, STriDER. One of STriDER’s design challenges is to determine its mechanical properties and control inputs that minimize the amount of externally supplied actuation energy required to take a single step. Past STriDER prototypes have successfully taken highly efficient dynamic steps, however, these former prototypes required significant manual ‘tweaking’ of its mechanical parameters to realize these steps. Additionally, STriDER’s optimal joint trajectories and actuation inputs have not been outputs of the previous design process. This work provides the first systematic process for the optimal co-design of a controlled multibody dynamic system such as STriDER.