arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2012.11790cs.LGcs.SYeess.SY
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强化学习中约束处理的动态罚函数方法

A Dynamic Penalty Function Approach for Constraints-Handling in Reinforcement Learning

Korea Advanced Institute of Science and Technology(韩国科学技术院);University of Wisconsin-Madison(威斯康星大学麦迪逊分校)

Haeun Yoo, Victor M. Zavala, Jay H. Lee

摘要:

强化学习(Reinforcement learning,RL)作为解决高维状态/动作空间和随机不确定性序列优化问题的一种有效方法,正引起人们的关注。许多这样的问题涉及由不等式约束表示的约束。本研究的重点是使用强化学习来解决有约束的最优控制问题。大多数RL应用研究都通过在奖励函数中添加违反约束的软惩罚项来处理不等式约束。然而,在训练神经网络以学习值(或Q)函数时,由于施加的大惩罚,可能会遇到由约束边界处的函数值的急剧变化引起的计算问题。训练过程中的这种困难可能会导致收敛问题,并最终导致闭环性能不佳。为了解决这个问题,本研究提出了一种动态惩罚(DP)方法,其中惩罚因子在训练过程中随着迭代情节的进行而逐渐系统地增加。我们首先检查的能力,一个神经网络表示一个价值函数时,均匀的,线性的,或DP功能,以防止违反约束。在一个简单的车辆控制问题中,将采用DP函数方法的深度Q网络(DQN)算法训练的智能体与采用其他常数惩罚函数的智能体进行了比较。结果表明,该方法可以提高神经网络的逼近精度,并提供更快的收敛时,接近一个解决方案。

英文摘要:

Reinforcement learning (RL) is attracting attention as an effective way to solve sequential optimization problems that involve high dimensional state/action space and stochastic uncertainties. Many such problems involve constraints expressed by inequality constraints. This study focuses on using RL to solve constrained optimal control problems. Most RL application studies have dealt with inequality constraints by adding soft penalty terms for violating the constraints to the reward function. However, while training neural networks to learn the value (or Q) function, one can run into computational issues caused by the sharp change in the function value at the constraint boundary due to the large penalty imposed. This difficulty during training can lead to convergence problems and ultimately lead to poor closed-loop performance. To address this issue, this study proposes a dynamic penalty (DP) approach where the penalty factor is gradually and systematically increased during training as the iteration episodes proceed. We first examine the ability of a neural network to represent a value function when uniform, linear, or DP functions are added to prevent constraint violation. The agent trained by a Deep Q Network (DQN) algorithm with the DP function approach was compared with agents with other constant penalty functions in a simple vehicle control problem. Results show that the proposed approach can improve the neural network approximation accuracy and provide faster convergence when close to a solution.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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