Gait development on Minitaur, a direct drive quadrupedal robot

Abstract

The development of dynamic, quadrupedal robots is becoming an increasing topic of interest with the growing demand for robotic interaction in the human environment, but they require adaptable control schemes to address the challenges encountered while traversing real world terrains. In this study, we explore improvements to both physical and control methods to a quadrupedal system in order to achieve fast, stable walking and trotting gaits. This analysis includes an investigation of physical compliance, 5-bar kinematics for trajectory shaping, and the implementation of ground and obstacle contact sensing. Structural and mechanical improvements were made to reduce undesired compliance to generate faster, more stable gaits. Contact sensing was implemented for identifying obstacles and deviations in surface level for negotiation of varying terrain. Overall, the incorporation of these features greatly enhances the mobility of the dynamic quadrupedal robot and helps to establish a basis for overcoming obstacles.

Design and driving model for the quadruped robot: An elucidating draft

“…The ghost Minitaur 65 (Figure 5(a)), developed by ghost robotics company, adopts a unique leg design of 5-bar motion (Figure 5(b)) and direct drive of the motor, exhibiting excellent performance in running, jumping, and other sports. 66 Researchers from Google, the University of California, Berkeley, and Georgia Institute of Technology have built a quadruped robot, based on Minitaur and named “Rainbow Dash.” 67 Based on the advantages of motor direct drive control and structure, “Rainbow Dash” realizes automatic control strategy in a short time, with no prior knowledge of the environment.…”

Biped Walking Based on Stiffness Optimization and Hierarchical Quadratic Programming

“…RHex, ATRIAS, and Minitaur are designed with physics elastic leg and direct drive joint to realize low inertia leg and torque control joint. The SLIP model is used to design the leg motion strategy, and realized uneven ground movement of the physical robot [ 6 , 7 , 8 ]. Compared with the linear inverted pendulum model, the elastic motion characteristics of the SLIP model allow it to greatly reduce the complexity of trajectory planning.…”

Design and Implementation of Symmetric Legged Robot for Highly Dynamic Jumping and Impact Mitigation

“…Leg design is often inspired by biological observation. Generally, the following leg topologies are used: prismatic [ 13 ], two joint series articulated [ 14 ], three joint series articulated (often redundantly) [ 15 ], parallel planar [ 16 , 17 , 18 ], symmetric parallel [ 10 , 19 ], and parallel spatial [ 11 ]. The prismatic leg is limited by its workspace, and the series articulated—particularly, the redundantly articulated leg—have an adequate motion range.…”

“…Although hydraulic actuation can provide robustness against high-impact forces and satisfy the power requirements in terms of velocity, torque, and bandwidth, it is not ideal for application in everyday situations. Therefore, this study focused on electric actuation, such as direct-drive (DD) [ 19 ], quasi-direct-drive (QDD) [ 20 ], heavy gear motors (HGM) [ 21 ], and series-elastic-drive (SEA) [ 22 , 23 ]. Although DD has the advantage of high force transparency and control bandwidth, it also has a few disadvantages, including lower torque density and thermal Joule heating.…”