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W. Fan and J. Xiong, “A homotopy method for continuous-time model-free LQR control based on policy iteration,” IEEE/CAA J. Autom. Sinica, 2025. doi: 10.1109/JAS.2025.125132
Citation: W. Fan and J. Xiong, “A homotopy method for continuous-time model-free LQR control based on policy iteration,” IEEE/CAA J. Autom. Sinica, 2025. doi: 10.1109/JAS.2025.125132

A Homotopy Method for Continuous-Time Model-Free LQR Control Based on Policy Iteration

doi: 10.1109/JAS.2025.125132
Funds:  This work was supported by the National Natural Science Foundation of China (62273320)
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  • In recent years, reinforcement learning control theory has been well developed. However, model-free value iteration needs many iterations to achieve the desired precision, and model-free policy iteration requires an initial stabilizing control policy. It is significant to propose a fast model-free algorithm to solve the continuous-time linear quadratic control problem without an initial stabilizing control policy. In this paper, we construct a homotopy path on which each point corresponds to an linear quadratic regulator problem. Based on policy iteration, model-based and model-free homotopy algorithms are proposed to solve the optimal control problem of continuous-time linear systems along the homotopy path. Our algorithms are speeded up using first-order differential information and do not require an initial stabilizing control policy. Finally, several practical examples are used to illustrate our results.

     

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