Rough-terrain locomotion and unilateral contact force regulations with a multi-modal legged robot

Abstract

The study for legged locomotion has made lots of achievements. However, the stability of the state-of-the-art bipedal robots are still vulnerable to external perturbation, cannot negotiate extreme rough terrains, and cannot directly regulate unilateral contact force.This thesis will introduce a thruster-assisted bipedal walking robot called Harpy. The objective is to integrate the merits of legged and aerial robots in a single platform. The robot's dynamics is simulated with simplifying assumptions. Furthermore, this research will show that the employment of thruster allows to stabilize the robot's frontal dynamics and apply model predictive control (MPC) to jump over obstacles to achieve multi-modal locomotion. In addition, we will capitalize the thruster actions to demonstrate an optimization-free approach by regulating contact forces using an Explicit Reference Governor (ERG). Then, we will focus on ERG-based fine-tuning of the joint's desired trajectories to satisfy unilateral contact force constraints.--Author's abstract