An Efficient Robot Precision Assembly Skill Learning Framework Based on Several Demonstrations
Yanqin Ma, Yonghua Xie, Wenjun Zhu, Song Liu
Abstract
This paper proposes an efficient robot assembly skill learning framework based on only a few demonstrations. The assembly skill learning process consists of two phases, e.g., the pre-training phase and the self-learning phase. In pre-training phase, the assembly networks are initialized from demonstration data. A novel data augmentation model based on state transition model is designed, which only requires several human demonstrations to learn the parameters of the model and reduces the cost of demonstration data collection in pre-training. In self-learning phase, the pre-trained assembly networks are further optimized by a hybrid exploration strategy in assembly environment, which explores both parameter space and action space to increase exploration efficiency. On par with the learning framework, a fuzzy reward function balancing the efficiency and compliance of assembly is elaborately designed to evaluate action’s performance in assembly skill self-learning process. Series of physical experiments were well conducted on a sophisticated assembly platform to verify the effectiveness of the proposed efficient robot assembly skill learning framework. Experimental results demonstrate that the learning efficiency of the proposed framework is at least three times as efficient as the state-of-art methods, while the skill performance outperforms the state-of-art by more than 50%. Note to Practitioners—The motivation of this paper is to develop a skill learning framework to achieve efficient assembly skill learning for robot in real-world system. The proposed framework is only based on several demonstrations, which shows high practicability for robot skill learning. The self-learning method is dexterously used to optimize the learned assembly skill from demonstrations since the limited space of demonstrations. Besides, the hybrid exploration strategy and fuzzy reward strategy are well designed to improve the behavior of self-learning. The proposed framework can improve the efficiency and performance of robot assembly learning skill. It is extremely important for robot working in practical applications.