比例减压阀控缸输出力的非线性自适应控制

Nonlinear Adaptive Control of Output Force for a Cylinder Controlled by Proportional Pressure Reducing Valves

  • 摘要: 针对所研制的一款采用双直动式三通比例减压阀控非对称液压缸驱动的刮板型输送带清扫器进行研究,提出了一种基于PI(Prandtl-Ishlinskii)逆模型前馈补偿的自适应控制算法,改善了比例减压阀固有的压力滞环、死区、增益等非线性,保证了清扫器刮板驱动扭矩的精度,实现了以恒定扭矩在刮板全寿命周期内的高效清洁. 针对比例减压阀的滞环特性,采用带遗忘因子的递推最小二乘法在线辨识比例减压阀的PI模型参数,进而求解其逆模型作为线性自抗扰控制器的前馈补偿. 仿真和实验结果表明,所提算法有效减小了比例减压阀的滞环、死区和增益等非线性,改善了比例减压阀控缸的动态响应,相较于PID算法,跟踪速度提升了65%,在100~700 N·m范围内刮板驱动扭矩误差可控制在±2 N·m以内.

     

    Abstract: The paper focuses on a blade-type conveyor belt cleaner operated by a dual direct-acting three-way proportional pressure-reducing valve-controlled (PPRV) asymmetric hydraulic cylinder. It proposed an adaptive control algorithm based on PI (Prandtl-Ishlinskii) inverse feedforward compensation to mitigate the pressure hysteresis, dead zone and gain nonlinearity inherent in the PPRVs. The primary aim was to ensure precise control of the blade's driving torque in a conveyor belt cleaner. The algorithm was designed to maintain consistent pressure against the conveyor belt and ensure effective cleaning throughout the blade's entire lifecycle. Through online identification of PI model parameters using a recursive least squares method with forgetting factors, the inverse model was resolved, enabling feedforward compensation for linear active disturbance rejection control based on the hysteresis characteristics of the PPRVs. Simulation and experimental results demonstrate the effectiveness of the proposed algorithm in reducing PPRV hysteresis, dead zone and gain nonlinearity, thereby improving the system's dynamic response. Compared to the PID algorithm, the proposed method exhibits a 65% increase in dynamic response, with blade driving torque error controlled within ±2 N·m in the torque range of 100~700 N·m.

     

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