Reinforcement learning with imitative behaviors for humanoid robots navigation: synchronous planning and control

Humanoid robots have strong adaptability to complex environments and possess human-like flexibility, enabling them to perform precise farming and harvesting tasks in varying depths of terrains. They serve as essential tools for agricultural intelligence. In this article, a novel method was proposed to improve the robustness of autonomous navigation for humanoid robots, which intercommunicates the data fusion of the footprint planning and control levels. In particular, a deep reinforcement learning model - Proximal Policy Optimization (PPO) that has been fine-tuned is introduced into this layer, before which heuristic trajectory was generated based on imitation learning. In the RL period, the KL divergence between the agent’s policy and imitative expert policy as a value penalty is added to the advantage function. As a proof of concept, our navigation policy is trained in a robotic simulator and then successfully applied to the physical robot GTX for indoor multi-mode navigation. The experimental results conclude that incorporating imitation learning imparts anthropomorphic attributes to robots and facilitates the generation of seamless footstep patterns. There is a significant improvement in ZMP trajectory in y-direction from the center by 21.56% is noticed. Additionally, this method improves dynamic locomotion stability, the body attitude angle falling between less than ± 5.5\(^\circ \) compared to ± 48.4\(^\circ \) with traditional algorithm. In general, navigation error is below 5 cm, which we verified in the experiments. It is thought that the outcome of the proposed framework presented in this article can provide a reference for researchers studying autonomous navigation applications of humanoid robots on uneven ground.