Abstract

This project investigates passive dynamic walking via the design, experimental construction, and theoretical modelling of a quadruped ramp walker. Unlike traditional powered robots, passive dynamic walkers are able to stably walk down a gentle slope with zero energy input and no active control purely from gravity. In addition to the theoretical scope of most existing literature, I also experimentally 3D printed various walker geometries with varying leg lengths, body width and leg sizes and investigated the walking motion for different ramp angles. An optical tracking system using AprilTag fiducial markers was used to track the pose of the walker, which involves using compter vision algorithms to detect markers pasted onto the walker. A dynamical theoretical model was derived accounting for all 10 degrees of freedom (the position, rotation and leg angles) to simulate the motion of the walker, showing good agreement with experimental results. Using this model, I investigate the different dissipation mechanisms such as inelastic collisions and friction leading to the walker reaching a terminal velocity down the ramp. Apart from quantitative data, I also describe qualitative trends for how varying parameters will affect the walking behaviour of the walker. These findings provide insightful intuition into how such a walker behaves which can aid the future development of more sustainable and efficient ultra-low-energy robotics in diverse fields such as disaster response, planetary exploration, and assistive prosthetics.