Deep-reinforcement-learning-based gait pattern controller on an uneven terrain for humanoid robots

Although conventional gait pattern control in humanoid robots is typically performed on flat terrains, the roads that people walk on every day have bumps and potholes. Therefore, to make humanoid robots more similar to humans, the movement parameters of these robots should be modified to allow them to adapt to uneven terrains. In this study, to solve this problem, reinforcement learning (RL) was used to allow humanoid robots to engage in self-training and automatically adjust their parameters for ultimate gait pattern control. However, RL has multiple types, and each type has its own benefits and shortcomings. Therefore, a series of experiments were performed, and the results indicated that proximal policy optimization (PPO), combining advantage actor-critic and trust region policy optimization, was the most suitable method. Hence, an improved version of PPO, called PPO2, was used, and the experimental results indicated that the combination of deep RL with data preprocessing methods, such as wavelet transform and fuzzification, facilitated the gait pattern control and balance of humanoid robots.