挖掘机电液控制系统进出口独立控制特性分析与实验研究

发布时间：2019-05-07 07:59

【摘要】：液压系统由于输出功率重量比大、响应快、控制精度高、可提供远程控制等特点,在航空航天、船舶、移动车辆、钢铁工业等领域得到了广泛应用。同时,液压系统与电子控制技术相融合,极大地推动了电液控制系统应用的快速增长。然而,液压系统是一种以高能耗换取优良操控性能的传动方式,其应用正日益受到其他传动技术(如机械传动、电气传动)的挑战。故在满足性能要求的前提下实现节能控制已成为液压领域焦点之一。传统的阀控液压系统利用一个多边节流的主控制阀芯同时控制液压执行器的进出口油路,在进口节流调速的过程中,出口同时进行节流,造成了多余的出口节流损失,系统能耗大、效率低。液压执行器进、出口独立节流控制技术在完成节流调速控制的同时,还可兼顾压力控制,因此,可以消除传统阀控液压系统中重复的节流损失。针对传统阀控液压系统在进出口节流控制中存在的局限性,提出了一种兼顾优良控制特性与低能耗的进出口独立控制系统解决方案,并对其中的进出口阀口开启特性、压差补偿特性、运动控制特性等关键问题进行深入研究。基于传统四通阀控液压系统的阀口开启路径方式,提出了七种典型的进出口独立控制系统阀口开启路径方式,并对其静态特性进行了分析。利用状态空间方程,建立了进出口独立控制系统的动态特性仿真模型,并进行了动态特性分析,得出了进出口独立控制系统最优的阀口开启路径方式。基于负载敏感系统的机液压差补偿原理,针对进出口独立控制系统的进出口开口度独立调节特性,得出了进口压差补偿方式和出口压差补偿方式。基于泵源压力的计算公式,得出了进口压差补偿系统和出口压差补偿系统最优的阀口开启路径方式。并进行了静态特性分析,得出了最优的压差补偿方式。基于阀前补偿和阀后补偿原理,建立了原负载敏感系统和阀前补偿进出口独立控制系统分析模型,分别对两系统在带载提升工况下进行了分析,并对进口压差补偿进出口独立控制系统的节能特性进行了分析。针对比例阀的死区、滞环特性,提出了死区滞环双向等效补偿方法,应用自适应惯性滤波器对压力信号进行了滤波,并设计了基于分区域的专家PID控制器的压差前馈—反馈复合控制策略,提升了进出口独立控制系统的线性控制特性。基于所提出的进出口独立控制系统解决方案,以6T挖掘机为试验验证平台,分别对单执行器运动和多执行器复合运动进行了试验研究。理论分析与试验结果表明:进出口独立控制系统在动臂、斗杆和铲斗的单执行器运动中节能特性相比现有系统可分别提高39.5%、36.6%和32.3%;在动臂铲斗复合运动、动臂斗杆复合运动、斗杆铲斗复合运动和动臂斗杆铲斗复合运动的节能特性分别可提高20.2%、25.6%、27.8%和20.8%。
[Abstract]:Hydraulic system has been widely used in aerospace, ship, mobile vehicle, iron and steel industry because of its high output power-weight ratio, fast response, high control precision, and can provide remote control, etc. The hydraulic system has been widely used in aerospace, ship, mobile vehicle, iron and steel industry and so on. At the same time, the integration of hydraulic system and electronic control technology has greatly promoted the rapid growth of the application of electro-hydraulic control system. However, hydraulic system is a kind of transmission with high energy consumption in exchange for excellent control performance, and its application is increasingly challenged by other transmission technologies, such as mechanical transmission and electrical transmission. Therefore, energy saving control has become one of the focuses in the hydraulic field on the premise of meeting the performance requirements. The traditional valve-controlled hydraulic system uses a multi-throttling main control valve core to control the inlet and outlet oil circuit of the hydraulic actuator at the same time. In the process of inlet throttling speed regulation, the outlet carries on the throttling at the same time, resulting in the excess outlet throttling loss. The system has high energy consumption and low efficiency. Independent throttle control technology for hydraulic actuator inlet and outlet not only completes throttle speed control, but also takes into account pressure control. Therefore, the repeated throttling loss in traditional valve controlled hydraulic system can be eliminated. In view of the limitation of the traditional valve-controlled hydraulic system in the control of inlet and outlet throttle, this paper puts forward a solution of the independent control system, which takes into account the excellent control characteristics and low energy consumption, and gives the opening characteristics of the inlet and exit valve ports among them. The key problems such as pressure difference compensation characteristics and motion control characteristics are deeply studied. Based on the valve opening path of the traditional four-way valve-controlled hydraulic system, seven typical ways of opening the valve opening path of the independent control system are put forward, and their static characteristics are analyzed. Based on the state space equation, the dynamic characteristic simulation model of the independent control system is established, and the dynamic characteristic analysis is carried out. The optimal valve opening path mode of the independent control system is obtained. Based on the principle of hydraulic pressure difference compensation for load sensitive system, the inlet pressure difference compensation mode and outlet pressure difference compensation mode are obtained according to the independent regulation characteristics of the inlet and exit opening degree of the independent control system. Based on the calculation formula of pump source pressure, the optimal opening path of inlet differential pressure compensation system and outlet differential pressure compensation system is obtained. The static characteristic analysis is carried out, and the optimal compensation method of pressure difference is obtained. Based on the principle of pre-valve compensation and post-valve compensation, the analysis models of the original load sensitive system and the independent control system of the pre-valve compensation inlet and outlet are established, and the analysis of the two systems under the load lifting condition is carried out respectively. The energy saving characteristics of the imported pressure difference compensation import and export independent control system are analyzed. According to the dead-time and hysteresis characteristics of proportional valve, a two-way equivalent compensation method of dead-time hysteresis is proposed. The adaptive inertial filter is used to filter the pressure signal. The pressure difference feedforward-feedback compound control strategy based on sub-domain expert PID controller is designed to improve the linear control characteristics of the independent control system. Based on the proposed solution of the independent control system for import and export, the single actuator motion and the multi-actuator composite motion were tested and studied on the 6T excavator as the test verification platform. The results of theoretical analysis and test show that the energy-saving characteristics of the independent control system can be increased by 39.5%, 36.6% and 32.3% respectively compared with the existing system in the single actuator motion of the boom, bucket rod and bucket. The energy-saving characteristics of the combined movement of the moving arm shovel and bucket, the combined movement of the movable arm bucket and the movable arm bucket can be increased by 20.2%, 25.6%, 27.8% and 20.8%, respectively, and the energy saving characteristics of the combined movement can be improved by 20.2%, 25.6%, 27.8% and 20.8% respectively.
【学位授予单位】：燕山大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：TU621;TP273

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