In order to improve the ride comfort and handling stability of the electro-hydraulic active suspension system, a hierarchical control strategy is proposed. For the active suspension system with body mass uncertainty and safety constraints, an enhanced constraint adaptive backstepping controller is designed to generate the target force of body vertical motion. When dealing with constraints, nonlinear filters are introduced, backstepping technology and quadratic Lyapunov function are used to combine the control target and domain constraints, and the vertical displacement of the body and the suspension deflection control index are synthesized into a single controlled variable, so that the control variable converging to zero meets the suspension dynamic displacement limit. The ride comfort and safety of the active suspension system are improved. Secondly, stability analysis is conducted on the zero dynamic error system to ensure that all safety performance indicators are bounded. The effects of external disturbances, parameter uncertainties and modelling errors on the force tracking accuracy of asymmetric cylinder electrohydraulic systems are addressed. A backstepping dynamic surface control method based on a nonlinear perturbation observer is proposed, which estimates the composite perturbation terms such as modelling error and external perturbation, and uses the estimated value of the nonlinear observer to design a feedforward compensating control term to offset the effect of the composite perturbation on the system performance. In addition, the dynamic surface control method is used to calculate the derivative of the target force input, which avoids the derivative explosion phenomenon and reduces the computational complexity of the system. Simulation test results show that this method reduces the computational complexity of the system and improves the control performance. And under random and bumpy road conditions, the root-mean-square value of sprung mass acceleration performance index is reduced by 48.354 % and 72.677 % compared with passive suspension, which improves the ride comfort of the vehicle.

中文翻译：

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电液执行器参数不确定和外部干扰的主动悬架分级控制


为了提高电液主动悬架系统的平顺性和操纵稳定性，提出了分级控制策略。针对具有车身质量不确定性和安全约束的主动悬架系统，设计了增强约束自适应反步控制器来生成车身垂直运动的目标力。在处理约束时，引入非线性滤波器，采用反步技术和二次李亚普诺夫函数将控制目标和域约束相结合，将车身垂向位移和悬架挠度控制指标综合为单个受控变量，使得控制变量收敛到零满足悬架动态位移极限。主动悬架系统的乘坐舒适性和安全性得到提高。其次，对零动态误差系统进行稳定性分析，确保所有安全性能指标有界。解决了外部干扰、参数不确定性和建模误差对非对称缸电液系统力跟踪精度的影响。提出一种基于非线性扰动观测器的反步动态表面控制方法，该方法估计建模误差和外部扰动等复合扰动项，并利用非线性观测器的估计值设计前馈补偿控制项来抵消复合扰动对系统性能的影响。此外，采用动态面控制方法计算目标力输入的导数，避免了导数爆炸现象，降低了系统的计算复杂度。 仿真测试结果表明，该方法降低了系统的计算复杂度，提高了控制性能。并且在随机、颠簸路况下，簧上质量加速性能指标均方根值较被动悬架降低了48.354%和72.677%，提高了车辆的乘坐舒适性。