###### Abstract  
This paper proposes a control scheme combining improved particle swarm optimization (IPSO) and adaptive linear active disturbance rejection control (ALADRC) to solve the high-speed train (HST) speed tracking control problem. Firstly, in order to meet the actual operation of a HST, a multi-mass point dynamic model with time-varying coefficients was established. Secondly, linear active disturbance rejection control (LADRC) was proposed to control the speed of the HST, and the anti-disturbance ability of the system was improved by estimating and compensating for the total disturbance suffered by the carriage during the operation of the HST. Meanwhile, to solve the problem of difficult parameter tuning of the LADRC, IPSO was introduced to optimize the parameters. Thirdly, the adaptive control (APC) was introduced to compensate for the observation error caused by the bandwidth limitation of the linear state expansion observer in LADRC and the tracking error caused by an unknown disturbance during the train's operation. Additionally, the Lyapunov theory was used to prove the stability of the system. Finally, the simulation results showed that the designed control scheme is more effective in solving the problem of HST speed tracking. high-speed train; speed tracking control; linear active disturbance rejection control; adaptive control; particle swarm optimization Article Speed Tracking Control of High-Speed Train Based on Particle Swarm Optimization and Adaptive Linear Active Disturbance Rejection Control [PERSON]  
of the whole train process. In addition, many control strategies such as fuzzy control, predictive control, and some optimization algorithms have been applied to the design of ATO systems [13; 14; 15; 16]. Compared with the PID controller, the above control strategies have a better control effect. However, the design of most control strategies is cumbersome, and it is necessary to establish an accurate HST mathematical model [17]. However, the interference of HSTs during operation is complex and unknown, and the HST itself has nonlinear and strong coupling characteristics. Thus, it is impractical to establish an accurate mathematical model of the HST. Therefore, it is necessary to design a speed tracking controller which does not depend on an accurate HST model and has strong anti-disturbance ability and high accuracy. Based on the idea of classical PID error feedback processing, a nonlinear active disturbance rejection control (ADRC) was proposed in [18]. However, ADRC has too many parameters that need to be set, which is not conducive to the application of practical engineering. Therefore, the nonlinear link in ADRC was linearized, and the linear active disturbance rejection control (LADRC) was proposed [19]. The LADRC mainly includes the linear tracking differentiator (LTD), linear extended state observation (LESO), and PD controller [20]. LESO can observe and compensate for the total disturbance of the system in real-time, which makes LADRC have a good anti-disturbance performance. This also greatly promotes the application of LADRC in practical engineering [21]. In [22], in order to solve the stability and fast response of the gas flowmeter in the testing process, a decoupling controller of gas flow facility was proposed based on LADRC. The overall influence of the two channels of internal uncertainty and external disturbance in the system was observed as the total disturbance through LESO. This can decouple the pressure-flow coupling system into two single-input and single-output systems. The simulation results showed that LADRC has stronger anti-disturbance performance and better decoupling effect compared with PID. In [23; 24], in order to improve the dynamic capability of the distribution network in the case of various grid defects, an improved LADRC controller was used to improve the control performance by compensating for the LESO observation disturbance error.