Effects of Limb Morphology on Transient Locomotion in Quadruped Robots The natural world hosts a few mammals that display both a high degree of agility and speed. However these animals have complex leg morphologies. Robot designers are thus faced with the dilemma of which morphology to employ when designing the next generation of agile legged robots. Thus this letter presents a novel investigation into the effects of limb morphology of quadrupeds during rapid transient maneuvers such as acceleration and deceleration. Three leg configurations inspired by nature (O, XType and AllAnkle) as well as AllKnee configurations are compared. Extensive large scale Monte Carlo simulations utilizing contactimplicit trajectory optimization methods were employed on 100 randomly generated robots of varying sizes to determine the optimal configuration for the task of rapid transient locomotion. After extensive analysis, the investigation revealed that an XType leg configuration outperformed all other configurations. Ultimately, these results will provide insight for the mechanical design of future agile quadruped robots.

Bionic Architecture Design and Robust RoughTerrain Locomotion for a HighPayload Quadrupedal Robot * In this work, an electrically actuated quadrupedal robot with bionic architecture, Pegasus, is reported. With investigating the anatomical skeleton of mediumsized dog, its movement mechanism, and dogxe2x80x99s joints, we conclude that the architecture design of quadrupedal robots can benefit from bionics research. There is an optimization for structural parameters, geometrical relationship, and motion range of each joint according to the findings in bionics. The bionic structure design is verified by analyzing mechanical performance and motion ability of the robot. The bionic architecture allows COG trajectory not to follow the terrain profile and COG fluctuations are significantly suppressed when going through rough terrains. In order to generate a stable COG trajectory with fewer pose fluctuations, the step sequence and four footholds in each step follow the typical biological gait pattern for dynamic walking over rough terrains while the robot can keep robust postures in efficient workspace for each leg. Moreover, Virtual Muscle model is realized for each legxe2x80x99s compliance control with two sets of virtual spring and damper, in order to absorb feet impacts on the ground.