混凝土泵送换向过程的变排量控制

为解决混凝土泵送换向时负载突变和活塞撞缸引起主油泵出口液压冲击的问题,提出了混凝土泵送换向过程的变排量控制方法。在周期性突变负载工况下,基于混凝土泵的开环特性,综合考虑泵送油缸结构参数和主油泵排量控制时间参数,在满足活塞不撞缸的物理约束下以泵送时间最短为评价标准,建立混凝土泵送换向过程的优化模型。以某型号的混凝土泵为例,对泵送油缸变排量控制信号点的位置参数和主油泵变排量控制的4个时间段参数进行了优化,并分别以水和混凝土为泵送对象进行了仿真和试验分析。研究结果表明：采用变排量控制方法后,主油泵出口液压冲击大约减小了67%,且没有发生活塞撞缸现象;该方法为解决周期性突变负载下混凝土泵送开环控制系统的设计问题提供了一个新的工程化途径。

Variable Displacement Control in Direction Changing Process of Concrete Pumping

To solve the hydraulic impact problem in the main pump export,which caused by abrupt changing load and piston striking the cylinder bottom in direction changing process,the variable displacement control method in direction changing process of concrete pumping was raised.Under periodically abrupt changing load conditions,the authors comprehensively considered the pumping cylinder structure parameters and the displacement control time parameters based on the system’s open-loop characteristic,took the shortest pumping time as the evaluation standard with the requirement of piston not striking the bottom of cylinder,and finally established a optimal model of concrete pumping direction changing process.The authors in the research took one type of concrete pump as an example,optimized the pumping cylinder structure parameters and the displacement control time parameters and then carried out simulation and experimental analysis for pumping both water and concrete.Results show that the hydraulic impact in the main pump export declines about 67% and the phenomenon of piston striking the cylinder doesn’t happen after taking the variable displacement control method in direction changing process.This method provides a new approach for solving the design problems in concrete pumping open-loop control system under periodically abrupt changing load conditions.