Robotic Grinding of Thin-Walled Parts: Reinforcement Learning-Based Chatter Suppression Method
摘要
To address chatter vibration in robotic thin-walled part grinding, this paper proposes a variable impedance control (VIC) method fusing deep deterministic policy gradient (DDPG) reinforcement learning with an imitation mechanism (IM). The method establishes dynamic mapping between vibration states and impedance parameters, which forms an integrated sensing-control scheme. Within the reinforcement learning (RL) framework, a multimodal state space is constructed by combining time-frequency domain features, including wavelet packet energy and force error. An imitation mechanism is introduced to generate state-action sample sets compliant with vibration dynamics for network pre-training, which effectively resolves the safety risks and training inefficiency issues encountered by reinforcement learning in real-world environments. Experimental results demonstrate that, compared with traditional impedance control (TIC), the proposed method suppresses characteristic chatter frequency amplitudes by over 34% and reduces force control errors by 50%. These results confirm its feasibility and effectiveness. This data-driven approach achieves closed-loop chatter detection and suppression without requiring precise system dynamics modeling, providing a novel solution for precision robotic machining in flexible manufacturing scenarios.