装载机工作装置的精细控制模式研究

发布时间：2018-06-20 14:42

本文选题：装载机 + 比例减压阀　；参考：《吉林大学》2011年硕士论文

【摘要】：随着机电一体化技术的发展,电液比例技术得到了很快的发展和普及,在现在工程车辆的控制系统上,电液比例技术有着广泛应用。装载机作为一种工程基础建设最常用的工程车辆,提高其控制系统性能以及简化操作过程都是非常重要和紧迫的。尤其是对于恶劣的工作环境,使用电液比例技术代替单纯依靠液压操作具有很大的优势。这不仅可以降低劳动强度,更重要的是提高操作精度,带来生产效率的提高。由于先导手柄在换向过程中受到弹簧力、液动力、摩擦力等因素的影响,并随着装载机功率和流量的增加而增加,这不仅会使操作力增大,操作者很容易疲劳,而且先导手柄的控制压力范围一定时,装载机主阀的先导控制压力和先导手柄不能完全的匹配。这都会使先导手柄不能精确的控制主阀芯的流量,甚至会造成流量突然增加或减少,进而造成斗或臂的突然冲击,对整个机械性能造成很大的损坏。本文利用电子技术对主阀芯的先导压力进行控制,将传感技术和脉宽调制技术综合应用实现对电液比例阀进行精确的控制。本文主要围绕着装载机的液压控制系统和电气控制系统进行讨论和研究。装载机工作装置的液压系统主要由铲斗和动臂组成,铲斗和动臂由两组非对称液压缸驱动。非对称液压缸作为装载机的执行机构,其本身的特性以及其控制性能将对装载机的性能产生直接的影响。所以本文首先建立了比例方向阀和阀控缸的模型,利用Simulink对液压系统数学模型进行分析和仿真,根据仿真结果分析液压系统的静态特性和动态特性。液压系统还包括比例减压阀,它是工作装置液压系统和电气控制系统的中间桥梁,也是电液比例控制系统的核心。首先对减压阀液压性能进行分析,建立了比例减压阀的数学模型,然后利用Simulink分析比例减压阀的动态特性。工作装置的电气控制部分主要控制比例减压阀和两组换向阀,实现对铲斗和动臂的控制。为了能达到精确的控制,本文分析了几种不同的控制方法,比较它们的控制效果,然后选择最优控制方法。首先对比例减压阀的控制电流信号的时域和频域进行分析,研究控制信号的控制特征,为控制方法的设计奠定基础。然后根据信号分析,对开环控制系统、模拟PID控制以及软件PID控制三种控制方法进行了分析和设计。开环控制系统中包括开环系统的硬件设计和性能分析,主要是对开环系统的抗干扰能力以及对液压系统的影响进行了分析。模拟PID控制利用比例电流作为反馈构成一个闭环系统,利用三角发生器和PID输出电压进行比较产生PWM对比例阀进行控制。这部分包括整个控制系统硬件设计,使用PSPICE进行硬件仿真,利用仿真结果对各部分的控制过程进行分析。软件PID控制主要是利用STM32F103单片机和uC/OS-II实现PID代替硬件实现控制,充分利用微控制集成的PWM功能来简化控制系统,并通过对PID优化来提高控制系统的稳定性。最后对三种控制方法进行了试验,测试了电气系统和液压系统的控制性能和动态响应,并观察控制系统的节约响应和抗干扰能力。通过试验对比,观察三种控制方法各自的优缺点。
[Abstract]:With the development of mechatronics technology, electro hydraulic proportional technology has been rapidly developed and popularized. On the control system of engineering vehicles, the electro-hydraulic proportional technology is widely used. As a most commonly used engineering vehicle, the loader is very important to improve the performance of its control system and simplify the operation process. And urgent. Especially for the bad working environment, the use of electro-hydraulic proportional technology instead of simply relying on hydraulic operation has a great advantage. This can not only reduce the labor intensity, but also increase the precision of operation, and bring about the increase of production efficiency.
The pilot handle is affected by spring force, hydraulic power, friction and other factors during the reversing process, and increases with the increase of the power and flow of the loader. This will not only increase the operating force, the operator is easy to fatigue, but also the pilot control pressure and the pilot handle of the main valve of the loader when the control pressure range of the pilot handle is certain. It can not be completely matched. This will make the pilot handle can not accurately control the flow of the main valve core, even cause the sudden increase or decrease of the flow rate, and then cause the sudden impact of the bucket or arm, causing great damage to the whole mechanical performance. This paper uses electronic technology to control the leading pressure of the main valve core, and the sensing technology and pulse width. The integrated application of modulation technology realizes the precise control of the electro-hydraulic proportional valve. This paper focuses on the discussion and research of the hydraulic control system and the electric control system of the loader.
The hydraulic system of the loader working device is mainly composed of bucket and arm, and the bucket and arm are driven by two groups of asymmetrical hydraulic cylinders. As the actuator of the loader, asymmetric hydraulic cylinder itself and its control performance will have a direct effect on the performance of the loader. The model of cylinder control is used to analyze and simulate the mathematical model of hydraulic system by Simulink. According to the simulation results, the static and dynamic characteristics of the hydraulic system are analyzed. The hydraulic system also includes the proportional pressure relief valve. It is the middle bridge of the hydraulic system and the electrical control system of the working device, and it is the core of the electro-hydraulic proportional control system. Analysis of hydraulic valve performance, establishes a mathematical model of proportional valve, dynamic characteristic analysis and then use Simulink proportional valve.
The electrical control part of the working device mainly controls the proportional pressure relief valve and two sets of reversing valves to control the bucket and the moving arm. In order to achieve accurate control, this paper analyzes several different control methods, compares their control effects, and then selects the optimal control method. First, the control of the proportional pressure relief valve is when the current signal is controlled. In the domain and frequency domain, the control characteristics of the control signal are studied, and the basis for the design of the control method is laid. Then, according to the signal analysis, the open loop control system, the analog PID control and the software PID control are analyzed and designed. The hardware design and performance analysis of the open loop control system are included in the open loop control system. The anti interference ability of the open loop system and the influence on the hydraulic system are analyzed. The analog PID control uses the proportional current as feedback to form a closed loop system, and makes use of the triangle generator and the PID output voltage to produce the PWM contrast valve control. This part includes the hardware design of the whole control system and the use of PSPICE into the system. The control process of each part is analyzed by the simulation results. The software PID control mainly uses the STM32F103 MCU and the uC/OS-II to realize the control of the hardware instead of the hardware, and makes full use of the PWM function of the micro control integration to simplify the control system, and improves the stability of the control system through the optimization of the PID.
Finally, the three control methods were tested, the control performance and dynamic response of the electrical and hydraulic systems were tested, and the saving response and anti-interference ability of the control system were observed. The advantages and disadvantages of the three kinds of control methods were observed and compared.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2011
【分类号】：TH243

【引证文献】