负载口独立控制可编程阀及其在智能挖掘机控制中的应用

发布时间：2018-05-28 08:09

本文选题：负载口独立控制 + 可编程阀　；参考：《浙江大学》2017年博士论文

【摘要】：随着工程机械和数字液压控制技术的发展,智能化工程机械与数字液压元件的结合成为未来的研究热点。现有工程机械专用多路阀阀体结构复杂、没有压力流量在线反馈,很难实现数字化控制;采用单阀芯调节进出油口节流面积,能量损耗高。本文发明了一种负载口独立控制可编程阀替代工程机械上多路换向阀,其集成了数字信号与负载口独立控制技术的优点,增加了系统控制自由度,减小了液压执行器背压,提高了工程机械液压系统的操控性并降低了能耗。同时,负载口独立控制可编程阀阀体结构简单,方便实现液压元件的模块化批量生产。本学位论文针对负载口独立控制可编程阀的创新设计,压力流量特性以及在挖掘机上的应用开展研究,选题具有重要的学术研究价值和很强的工程应用前景。本文所研制的负载口独立控制可编程阀首创设计了两个高速开关阀作为先导阀控制主阀芯组成一个阀控单元,由两个阀控单元分别控制液压执行器(液压缸、液压马达)的进油口和出油口,阀控单元内设置有压力传感器、主阀芯位移传感器和CAN总线接口在线测量并反馈压力流量,可提高液压系统的控制精度。本文建立了以比例阀为先导和高速开关阀为先导的负载口独立控制可编程阀的数学模型和数学仿真模型,研究了高速开关阀的频率和输出先导压力对可编程阀主级的影响。高速开关阀频率越高,先导控制流量调整越快,在调整时间内先导控制腔压力变化幅值越小,主阀芯位移与输出流量越稳定;适当提高高速开关阀输出先导压力可以增加作用在主阀芯上的先导控制力,可使主阀芯运动加速。通过仿真和试验,可对比比例先导和高速开关先导两种形式可编程阀的静动态性能指标,一方面,静态特性表明高速开关先导可编程阀对主阀口死区非线性因素不敏感,导阀流量增益较比例先导阀更高,而比例先导可编程阀有更好的线性度和稳定性;另一方面,动态响应结果表明高速开关先导可编程阀的频率响应比比例先导可编程阀提高了 20%。本文提出了一种以液压执行器两腔压力与负载速度反馈的背压自适应式双级解耦压力流量控制方法。可编程阀第一级控制器解耦控制液压执行器进出口压力,保证执行器背压腔的压力始终稳定在1MPa;第二级控制器以执行器两腔压力和执行器的运动速度为输入,可编程阀的先导阀控制信号为输出,分配可编程阀控液压系统的压力流量。本文对比分析了液压缸在20mm/s和l00mm/s的阶跃信号下位移、两腔压力和控制信号的情况,仿真和试验结果表明,液压缸在20mm/s的阶跃信号下,速度调整时间为0.2s,流量调整时间为0.25s,速度稳态误差小于2.5%;液压缸在100mm/s的阶跃信号下,速度调整时间为0.5s,流量调整时间为0.55s,速度稳态误差为5%。结合负载口独立阀控系统特征,研究了多执行器位移与速度的控制精度。试验表明,在跟踪1Hz、±1Omm的位移信号下,可编程阀控制器的位移误差在±2mm以内,且位移控制优于速度控制。本文设计了负载口独立控制可编程阀挖掘机液压新系统,该系统无需配置各种不同的功能阀,仅通过改变负载口独立控制可编程阀的程序,即可实现挖掘机的典型液压系统回路功能,如:正流量控制、行走、回转、流量优先和流量再生等。新系统用电信号替代了传统液压手柄控制信号和梭阀网络,大幅简化了原有挖掘机液压系统。本文还提出了一种适用于负载口独立控制可编程阀液压挖掘机系统的时间最优轨迹规划方法对挖掘机铲斗齿尖的轨迹进行规划,可实现挖掘机直线自动挖掘,在限制铲斗执行器最大速度15mm/s的情况下,行程3.7m的直线作业,能够在18.4s内完成工作,作业效率提高了 15.64%。本论文的主要研究内容如下:第一章,指出了论文的研究目的和意义。介绍了可编程阀与负载口独立控制技术的研究背景和国内外发展现状。根据技术特点,对挖掘机智能控制系统的研究进行分类。确定了本文的研究内容与研究难点。第二章,提出负载口独立控制可编程阀的设计目标和实现功能。分别对以比例阀为先导和高速开关阀为先导的两种可编程阀数学与仿真建模,仿真与试验分析了高速开关阀参数对主阀性能的影响。通过试验对比了比例先导可编程阀与高速开关先导可编程阀的静态和动态性能。本章还搭建了可编程阀综合性能测试试验台,用于测试可编程阀的各项性能指标。第三章,提出了一种可以切换原有挖掘机液压系统和负载口独立控制可编程阀液压系统的挖掘机改造方案。通过改变可编程阀的功能,实现挖掘机的正流量控制、行走、回转、流量优先与流量再生功能。各典型回路所用的可编程阀完全相同,仅通过更改程序实现功能的选择和切换。第四章,首先,建立负载口独立控制可编程阀液压系统模型,设计数字压力补偿器保证阀口压差恒定,利用阀口压力传感器和阀芯位移传感器得到计算反馈流量。其次,提出了一种双级解耦压力流量控制方法,第一级控制器解耦控制进出油口压力,第二级控制器分配液压系统压力流量。通过仿真与试验,对比了执行器工作在低速和高速时的调整时间和稳态特性。最后,讨论了多执行器复合运动时位移和速度的控制精度。第五章,建立负载口独立控制可编程阀系统挖掘机虚拟仿真平台和运动学模型。通过挖掘机运动学的正逆解,确定挖掘机铲斗齿间与各个执行器行程之间的对应关系。以时间最优轨迹规划方法对挖掘机铲斗齿尖的轨迹进行规划,求解挖掘机回转、动臂、斗杆和铲斗的位移、速度和加速度。第六章,对本论文的研究工作进行总结,给出了主要的研究结论,指出了课题的创新点,并对未来的研究工作进行展望。
[Abstract]:With the development of engineering machinery and digital hydraulic control technology, the combination of intelligent engineering machinery and digital hydraulic components has become a hot spot in the future. The existing multi-channel valve body of the existing engineering machinery is complex, it is difficult to realize digital control without pressure flow online feedback, and the throttle area and energy of the inlet and outlet are adjusted by single valve core. The loss is high. In this paper, a multi-channel valve replacement valve is invented, which integrates the advantages of the digital signal and the independent control technology of the load port. It increases the control freedom of the system, reduces the back pressure of the hydraulic actuator, improves the manipulability of the hydraulic system of the engineering machinery and reduces the energy consumption. The load port independent control programmable valve body is simple in structure and facilitates the modular production of hydraulic components. This dissertation focuses on the innovative design of the programmable valve, the characteristics of pressure flow and the application on the excavator. This thesis has a heavy academic value and a strong engineering application. Two high-speed on-off valves are designed as a pilot valve to control the main valve core to form a valve control unit. The valve control unit controls the inlet and outlet of the hydraulic actuator (hydraulic cylinder, hydraulic motor), and the pressure sensor is set in the valve control unit and the main valve core displacement is set in the valve control valve. The sensor and the CAN bus interface can measure and feed back the pressure flow on line, which can improve the control precision of the hydraulic system. In this paper, a mathematical model and a mathematical simulation model of a programmable valve with a proportional valve as the pilot and a high speed switch valve are established. The frequency and the output pilot pressure of the high speed switch valve are studied. The higher the frequency of the valve is, the higher the frequency of the high speed switch valve, the faster the flow adjustment of the pilot control, the smaller the amplitude of the pressure change in the adjustment time, the more stable the displacement of the main valve core and the output flow, and the appropriate increase of the pilot control force on the main valve core by increasing the output pilot pressure of the high speed switch valve, and the movement of the main valve core can be moved. Acceleration. Through simulation and test, the static and dynamic performance indicators of two forms of programmable valves are compared. On the one hand, the static characteristics show that the high speed switch pilot valve is insensitive to the nonlinear factors of the dead zone of the main valve port, the flow gain of the guide valve is higher than that of the pilot valve, and the proportional pilot valve is more than the pilot valve. Good linearity and stability; on the other hand, the dynamic response results show that the frequency response of the high speed switch pilot valve is higher than that of the proportional pilot valve. 20%. proposed a back pressure adaptive double decoupling pressure flow control method using the back pressure of the hydraulic actuator two cavity pressure and the load speed. The programmable valve first is first. The level controller decouple control the pressure of the hydraulic actuator import and export, ensure the pressure of the actuator back pressure is always stable in 1MPa; the second stage controller takes the actuator two chamber pressure and the actuator's moving speed as input, the pilot valve control signal of the programmable valve is output, and the pressure flow of the programmable valve controlled hydraulic system is allocated. The displacement of the step signal of the hydraulic cylinder in 20mm/s and l00mm/s, the two cavity pressure and the control signal are analyzed. The simulation and test results show that the speed adjustment time is 0.2S under the step signal of 20mm/s, the adjustment time of the flow is 0.25s, the speed steady error is less than 2.5%, and the speed adjustment time is under the step signal of the hydraulic cylinder under the 100mm/s step signal. For 0.5s, the flow adjustment time is 0.55s and the velocity steady-state error is 5%. combined with the characteristics of the independent valve control system of the load port. The control precision of the displacement and speed of the multi actuator is studied. The experiment shows that the displacement error of the programmable valve controller is less than 2mm under the tracking of 1Hz and the displacement signal of + 1Omm, and the displacement control is superior to the speed control. This paper is designed in this paper. The new hydraulic system of the programmable valve excavator is controlled by the independent load port. The system can realize the typical hydraulic system circuit function of the excavator by changing the program of independent control of the programmable valve by changing the load port, such as positive flow control, walk, turn, flow priority and flow regeneration. The electric signal replaced the traditional hydraulic control signal and the shuttle valve network, and greatly simplified the original excavator hydraulic system. This paper also proposed a time optimal trajectory planning method for the hydraulic excavator system for the independent control of the load port, and the path of the bucket tooth tip of the excavator was planned, and the straight line of the excavator could be realized. Automatic mining, in the case of limiting the maximum speed of 15mm/s of the bucket actuator, a straight line operation of 3.7m, can complete the work in 18.4s. The work efficiency improves the main research content of this paper as follows: Chapter 1, the purpose and significance of the research are pointed out. The research on the independent control technology of the programmable valve and the load port is introduced. According to the technical characteristics, the research on the intelligent control system of excavator is classified. The research contents and research difficulties of this paper are determined. Second chapter, the design goal and the realization function of the programmable valve are put forward, and the two types of the pilot of the proportional valve as the pilot and the high speed switch valve are respectively put forward. The influence of the parameters of the high speed switch valve on the performance of the main valve is analyzed by the mathematical and simulation modeling of the programmable valve. The static and dynamic performance of the programmable valve of the proportional pilot and the high speed switch pilot is compared through the experiment. The test test rig of the programmable valve's comprehensive performance is also built in this chapter, which is used to test the various types of the programmable valve. In the third chapter, a transformation scheme of excavator is proposed, which can switch the hydraulic system of the original excavator and the load port to control the hydraulic system of the programmable valve. By changing the function of the programmable valve, the function of the positive flow control, walking, turning, flow priority and flow regeneration of the excavator is realized. The range valve is exactly the same, only by changing the program to realize the choice and switch of the function. In the fourth chapter, first, the hydraulic system model of the load port independent control programmable valve is set up, the digital pressure compensator is designed to guarantee the constant pressure difference of the valve mouth, and the valve pressure sensor and the valve core displacement sensor are used to calculate the feedback flow. Secondly, a kind of double is proposed. The first stage decoupling control method, the first stage controller decoupling control in and out of the oil inlet pressure, the second level controller distributes the pressure flow of the hydraulic system. Through the simulation and test, the adjustment time and steady state characteristics of the actuator at low speed and high speed are compared. Finally, the control of the displacement and speed of the multiple actuator is discussed. In the fifth chapter, the virtual simulation platform and kinematics model of the independent control programmable valve system excavator are set up. Through the positive inverse solution of the excavator kinematics, the corresponding relationship between the bucket teeth of the excavator and the various actuators is determined. The trajectory of the bucket tooth tip of the excavator is planned by the time optimal trajectory planning method. To solve the displacement, speed and acceleration of the excavator revolving, the arm, the bucket and the bucket. Chapter sixth, summarizes the research work of this paper, gives the main research conclusions, points out the innovation points of the project, and looks forward to the future research work.
【学位授予单位】：浙江大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：TU621

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