Implementation of Deep Deterministic Policy Gradients for Controlling Dynamic Bipedal Walking

Autor: Chujun Liu, Andrew G. Lonsberry, Mark J. Nandor, Musa L. Audu, Alexander J. Lonsberry, Roger D. Quinn
Jazyk: angličtina
Rok vydání: 2019
Předmět:
Zdroj: Biomimetics, Vol 4, Iss 1, p 28 (2019)
Druh dokumentu: article
ISSN: 2313-7673
DOI: 10.3390/biomimetics4010028
Popis: A control system for bipedal walking in the sagittal plane was developed in simulation. The biped model was built based on anthropometric data for a 1.8 m tall male of average build. At the core of the controller is a deep deterministic policy gradient (DDPG) neural network that was trained in GAZEBO, a physics simulator, to predict the ideal foot placement to maintain stable walking despite external disturbances. The complexity of the DDPG network was decreased through carefully selected state variables and a distributed control system. Additional controllers for the hip joints during their stance phases and the ankle joint during toe-off phase help to stabilize the biped during walking. The simulated biped can walk at a steady pace of approximately 1 m/s, and during locomotion it can maintain stability with a 30 kg·m/s impulse applied forward on the torso or a 40 kg·m/s impulse applied rearward. It also maintains stable walking with a 10 kg backpack or a 25 kg front pack. The controller was trained on a 1.8 m tall model, but also stabilizes models 1.4–2.3 m tall with no changes.
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