电液伺服泵的分数阶无抖振滑模控制

电液伺服泵（IEHSP）由于在结构上实现了伺服电机和液压泵共转子、共壳体高度融合，在体积、噪声和效率等方面具有明显优势，具有很好的应用前景。为了提高电液伺服泵的调速性能与抗扰能力，设计了一种新型分数阶滑模控制器（NFOSMC）。首先，由于分数阶微积分理论的引入，控制器为系统提供了更多的控制余度。然后，针对传统滑模控制中存在的抖振问题，通过设计使控制器中直接包含有切换项的分数阶积分项，利用其滤波特性可以有效滤除抖振，实现无抖振滑模控制。同时利用Lyapunov稳定性定理证明了控制器可以保证系统在存在内扰与外扰时能够在有限时间内收敛于平衡点，另外控制器中避免了含有高阶分数阶微分项，扩大了分数阶阶数的取值范围。为了进一步提高抗扰能力，设计了分数阶扰动观测器（FODOB），对系统内扰和外扰实时观测并补偿，有效提高了控制器的响应速度和刚度。最后，分别与PI控制、整数阶滑模控制器（IOSMC）和传统分数阶滑模控制器（CFOSMC）进行了仿真分析比较，结果表明该控制器能够有效改善速度跟踪性能和增强抗扰能力，消抖效果显著。 

Free-chattering fractional order sliding mode control of integrated electro-hydraulic servo pump

Thanks to the special structure with the same rotor and housing shared by higher degree integrated servo motor and pump, integrated electro-hydraulic servo pump (IEHSP) has significant advantages in aspects of size, noise, efficiency, etc., and it has good application prospect. To improve IEHSP's speed regulation performance and anti-disturbance ability, a novel fractional order sliding mode controller (NFOSMC) is designed. First, the controller provides the system with more degrees of freedom because of introduction of fractional order calculus. Second, aimed at chattering problem of traditional sliding mode control, it is ensured that the fractional order integral action of switching term is included directly in the proposed controller, so that free-chattering sliding control can be achieved by utilizing its filtering property. Meanwhile, the finite time convergence stability is proved via Lyapunov theorem in presence of internal and external disturbance. Besides, the range of order for fractional order is extended due to the high order fractional differential term avoidance. To further enhance the ability of anti-disturbance, fractional order disturbance observer (FODOB) is proposed for observation and compensation of internal and external disturbance, so the response speed and stiffness of the controller is enhanced effectively. By comparison with PI, counterpart integer order sliding mode controller (IOSMC) and conventional fractional order sliding mode controller (CFOSMC), the simulation results indicate that NFOSMC based on FODOB can effectively improve the performance of speed tracking and the ability of disturbance rejection, and the effect of chattering elimination is remarkable.