OPTEC - K.U.Leuven Center of Excellence: Optimization in Engineering

"Dynamic Locomotion with a Wheeled-Legged Quadruped Robot"
Prof. Inna Sharf, McGill University

Abstract:
In this talk, we present an overview of the work carried out in the Mechatronic Locomotion Laboratory at McGill University on a quadruped robotic platform, PAW. This robot features four springy legs with rotary actuation at the hips and wheels mounted at the  distal ends of the legs. The robot was designed to explore hybrid modes of locomotion, where it makes use of both wheels and legs to achieve novel behaviours. As well, the robot’s simple construction allows PAW to exploit the dynamics of a mass-spring system to achieve gaits such as bounding, galloping and jumping. In this presentation, we will first describe the basic design of the robot, its sensing capabilities, the control strategy implemented on the robot and the dynamics model of the robot, the latter developed using MSC Adams and Simulink software. We will then discuss in some detail several modes of locomotion that have been developed on the robot over the past three years.
Specifically, we present results for inclined turning and sprawled breaking achieved with the robot and a detailed investigation of the bounding gait with blocked and actuated wheels. The most recent addition to the robot’s repertoire is a dynamic jump. We will discuss the main stages of the jumping process and how the parameters governing the jump were optimized using the genetic algorithm coupled with the results of ADAMS/Simulink co-simulation. A simplified analytical model of the robot is also presented and dimensional analysis is employed to gain insight into the geometric and inertial parameters affecting the jump. The talk will conclude with some insights into further development of legged locomotion with robotic platforms.