Aiming at addressing the problem of manoeuvring decision-making in UAV air combat, this study establishes a one-to-one air combat model, defines missile attack areas, and uses the non-deterministic policy Soft-Actor-Critic (SAC) algorithm in deep reinforcement learning to construct a decision model to realize the manoeuvring process. At the same time, the complexity of the proposed algorithm is calculated, and the stability of the closed-loop system of air combat decision-making controlled by neural network is analysed by the Lyapunov function. This study defines the UAV air combat process as a gaming process and proposes a Parallel Self-Play training SAC algorithm (PSP-SAC) to improve the generalisation performance of UAV control decisions. Simulation results have shown that the proposed algorithm can realize sample sharing and policy sharing in multiple combat environments and can significantly improve the generalisation ability of the model compared to independent training.
Rotational speed stability is an important evaluation indicator of the performance of a hydro-viscous clutch (HVC). To improve the rotational speed stability of HVCs in mixed lubrication and the running condition of the friction pairs, the speed stability of an HVC in mixed lubrication was studied. To this end, the friction coefficients of both copper-based and paper-based friction pairs were experimentally tested using an MM1000-III wet friction machine. Theoretically, a torsional vibration model of the system is presented. The phase plane analysis method is applied to evaluate the stability of the torsional vibration model, where a critical negative gradient (CNG) is defined. The results show that the friction coefficient in mixed lubrication is an important parameter for the stability of the rotational speed. The system will be unstable when the negative gradient of the friction coefficient-slip speed is larger than the CNG. According to the definition of the CNG, suggestions regarding choice of friction pairs are made to improve the rotational speed stability of an HVC in mixed lubrication.
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