基于多智能体全局优化的液压支架成组调直方法

    A group straightening method for hydraulic supports based on multi-agent global optimization

    • 摘要: 采煤工作面直线度对围岩稳定性和回采效率至关重要。为了解决回采过程中煤壁、顶底板动态变化造成的难以建立准确的液压支架群最优调直控制模型的问题,提出了以马尔可夫决策过程为基础的多智能体调直控制方法。在该方法中,将各液压支架智能体化,从而避免对控制模型的依赖;同时,建立了液压支架成组调直的多智能体决策模型,智能体之间相互协作,采用强化学习实现了成组调直的最优决策。针对液压支架调直时执行的拉架动作是连续数值的特点,将单智能体TD3(Twin Delayed Deep Deterministic Policy Gradient)算法扩展到液压支架多智能体调直过程中;为了加快多智能体条件下调直策略的收敛速度,在多智能体强化学习框架中的Actor−Critic网络结构中引入层归一化处理,层归一化将各层输入数据重新汇聚在统一的概率分布下来加快神经网络权重的收敛。针对液压支架成组调直中多智能体最优策略求解困难的问题,设计了一种全局动作优化模块对液压支架多智能体的决策结果进行全局优化。此外,根据采煤工作面的工程实际,基于Gym框架(OpenAI Gym)开发了液压支架成组调直智能决策仿真平台,并开展了基于不同算法的液压支架成组调直试验。试验结果表明,提出的算法在直线度的平均值和均方差方面明显优于其他算法,当“S弯”成组支架数量为7个时,所提算法的工作面直线度较MA−TD3(Multi-Agent Twin Delayed Deep Deterministic Policy Gradient)算法提升了86%,标准差减少了71%。

       

      Abstract: The linearity of the mining face is crucial for the stability of surrounding rocks and the efficiency of coal recovery. To address the issue of establishing an accurate control model to achieve the optimal group straightening of the hydraulic supports during the mining process, which is affected by dynamic changes in the coal wall, roof and floor, a multi-agent decision model for group straightening of hydraulic supports is proposed based on Markov decision process (MDP). Each hydraulic support is treated as an agent, thus avoiding reliance on control models. A multi-agent decision model for group straightening of hydraulic supports is established, where the agents collaborate with each other to achieve optimal decisions for the group straightening using reinforcement learning (RL). Given that the actions during hydraulic supports straightening are continuous numerical, the twin delayed deep deterministic policy gradient (TD3) algorithm is extended to the multi-agent straightening process of hydraulic supports. To overcome the slow convergence speed of straightening policies under multi-agent conditions, layer normalization is introduced into the Actor-Critic network structure. This helps to aggregate the inputs of each layer under a unified probability distribution, accelerating the convergence of the neural network weights. To solve the difficulty of determining the optimal policy for multi-agent, a global action optimization (GAO) module is proposed, which globally optimizes the decision outcomes of multi-agent hydraulic supports, thereby achieving the optimal decision for hydraulic supports group straightening. Furthermore, based on the engineering practice of the coal mining face, a simulation platform for intelligent decision-making in group straightening of supports is developed using the Gym framework (OpenAI Gym). The experimental results show that the algorithm proposed in this paper significantly outperforms other algorithms in terms of the average value and standard deviation of linearity. When the number of “S-bend” grouped supports is seven, the proposed algorithm improves the coal mining face linearity by 86% compared to the MA-TD3 algorithm, and reduces the standard deviation by 71%.

       

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