BeeTLe: Blind Terrain-aware Learned Locomotion

Abstract

One of the largest challenges in the deployment of legged robots in the real world is deriving effective general gaits. In this paper, we present BeeTLe, which is a framework that enables terrain aware locomotion without the need for dedicated terrain sensors. BeeTLe is realised as a multi-expert policy Reinforcement Learning (RL) algorithm. This enables multiple gaits, applicable to different surface types, to be stored and shared in a single policy. Sensor free terrain awareness is incorporated using a Recurrent Neural Network (RNN) to infer surface type purely from actuator positions over time. The RNN achieves an accuracy of 94% in terrain identification out of 8 possible options. We demonstrate that BeeTLe achieves a greater performance than the baselines across a series of challenges including: the traversal of a flat plane, a tilted plane, a sequence of tilted planes and geometry modelling a natural hilly terrain. This is despite not seeing the sequence of tilted planes and the natural hilly terrain during training.The code, policy and simulated environments are available at: https://gitlab.surrey.ac.uk/rf00350/BeeTLe