基于CPR的混合动力挖掘机液压节能系统及其控制研究

发布时间：2018-07-23 14:33

【摘要】：能源危机和环境污染现象的持续加重，已经逐渐成为制约人类社会健康发展的关键问题。尤其对于具有用量大、效率低、排放差特点的挖掘机，对其进行节能研究不但有利于缓解能源压力、保护环境而且对其他类型的工程机械具备指导意义。由于液压混合动力技术具备功率密度大、全充和全放能力强和可以回收能量的优点，所以是最具产业化应用前景的先进技术之一。但迄今为止，对于液压混合动力挖掘机的研究还大多局限于某个子回路，尤其缺少从宏观上对于整机的系统设计以及所衍生出的能量控制策略、执行元件控制性能等问题的研究，导致这种技术的实际应用受到很大限制。本文以国家自然科学基金项目“节能型静液传动混合动力系统的理论基础及相关技术研究”等为依托，以基于CPR的混合动力挖掘机液压系统为研究对象，从整机液压系统的分析设计到实际实施过程中的关键技术进行了全面深入的研究。结合着国内外混合动力挖掘机的发展现状，分别横向比较了液压混合动力和电动混合动力的特点以及纵向比较了采用各自技术的具体机型。选定基于CPR的液压混合动力技术作为深入研究对象，并综述了该技术的发展现状和趋势。提出切换控制的基于CPR的混合动力挖掘机液压系统结构并阐述了工作原理。采用结合理论分析和关键元件单独测试的方法建立了整机的数学模型，并对新系统中新增的元件提出了选型方法。通过动力学分析的方法对例如液压缸摩擦系数以及机械臂转动惯量等无法直接获得但又对仿真分析具备较大影响的参数进行了机械臂单独运动情况下的辨识分析，并利用机械臂复合工况试验结果对其进行了验证。然后，利用获得的整机参数，以标准工况下发动机油耗最小为优化目标，利用离散动态规划算法对挖掘机的关键元件参数进行了优化匹配分析，从而降低了整机油耗。通过对比量化分析了基于LUDV原理的原挖掘机和本文提出的新型液混挖掘机在相同工况下的能耗情况，结果表明新系统可节能37%，而且结合着新型液混挖掘机的能耗分布情况，提出了通过降低控制油路溢流压力来进一步节能的方法。设计了适用于新型液混挖掘机的分层控制系统结构，明确了每层的任务并以中间层即控制策略设计为主要研究内容，，研制了三种具备工程实践价值的基于规则的控制策略，其中可调单点准恒压控制策略综合效果最好。针对提出的可降低油耗的控制策略可能降低执行元件控制性能的问题，对控制油路的先导机构设计了增加积分项的前向补偿的滑模控制器，能够在降低控制油路压力的前提下实现不损失控制性能的目的。对于新增的传感器容易受到干扰的问题，尤其是首次引入的陀螺仪的抗干扰能力较差，开发了基于新型观测器的速度控制系统，保证在传感器非正常工作条件下仍能获得较好的控制性能。最后，针对液压变压器控制液压缸系统具有耦合和强非线性问题，设计了结合动压反馈和模糊控制的控制器，从而不需要关注系统模型的内部结构，提高了液压缸速度控制的鲁棒性。本文最后进行了实机实验和台架模拟实验。首先，对一台基于LUDV原理的5t级挖掘机增加了数据采集系统，并进行了标准工况的测试，利用试验数据进行了能耗分析，验证所建模型的准确性。然后，采用发动机直接驱动液压泵/马达且以溢流阀模拟负载的方式对提出的增加积分项的前向补偿滑模控制器进行了实验，结果表明了该算法可有效的提高变量（变压）机构位置控制系统的准确性和鲁棒性。对回转装置进行了基于CPR原理的改造，通过空载和重载的实验证明了提出方案的可行性。然后，搭建了液压变压器控制液压缸的模拟实验平台，分别进行了液压变压器配流盘转角控制和液压缸的位置控制实验，实验结果表明该控制方式可以完成预设任务，虽然精度不高，但适用于挖掘机这种对于准确性要求较低的工程机械领域。
[Abstract]:The continuous aggravation of the energy crisis and the environmental pollution has gradually become the key problem that restricts the healthy development of the human society. Especially for the excavators with the characteristics of large amount, low efficiency and poor emission, the study of energy conservation is not only helpful to alleviate the pressure of energy, protect the environment but also have guidance to other types of engineering machinery. Hydraulic hybrid power technology has the advantages of high power density, full full charge and full discharge capacity and can recover energy, so it is one of the most advanced technologies with the most industrial application prospects. But so far, the research on Hydraulic Hybrid excavators is mostly limited to a certain sub circuit, especially the lack of macro to the whole. The research on the system design, the derived energy control strategy and the performance of the executive component control results in the practical application of this technology greatly limited. This paper is based on the National Natural Science Foundation Project "the theoretical foundation of the energy saving hydrostatic transmission hybrid system and the related technology research", based on CPR The hydraulic system of the hybrid power excavator is the research object, and the key technology in the process of the actual hydraulic system analysis and design to the actual implementation process is thoroughly studied.
Combined with the development status of hybrid power excavators both at home and abroad, the characteristics of hydraulic hybrid power and electric hybrid power are compared and the specific models are compared longitudinally. The hydraulic hybrid power technology based on CPR is selected as the research object, and the development status and trend of this technology are summarized. The structure of the hydraulic system of the hybrid power excavator based on CPR is switched and the working principle is expounded. The mathematical model of the whole machine is established by combining the theoretical analysis and the single test of the key components. The selection method of the new components in the new system is put forward. The friction coefficient of the hydraulic cylinder, for example, is analyzed by the method of dynamic analysis. The identification and analysis of the parameters which can not be obtained directly but have a great influence on the simulation analysis are carried out under the individual motion of the manipulator, and the results are verified by the results of the complex working condition of the manipulator. Then, the engine fuel consumption is optimized under the standard condition by using the obtained machine parameters. The discrete dynamic programming algorithm is used to optimize and match the parameters of the key components of the excavator, thereby reducing the fuel consumption of the whole machine.
By comparing and quantifying the energy consumption of the original excavator based on LUDV principle and the new type liquid concrete excavator in the same working condition, the results show that the new system can save energy 37%, and combined with the energy consumption distribution of the new type liquid mixing excavator, the method of further saving energy by reducing the overflow pressure of the control oil road is put forward. The structure of the hierarchical control system for the new type liquid mixing excavator is taken into account. The task of each layer is clarified and the middle layer is the main research content. Three rules based control strategies have been developed, in which the single point quasi constant pressure control strategy has the best comprehensive effect.
In order to reduce the oil consumption control strategy, the control performance of the actuator may be reduced. A forward compensating sliding mode controller with integral terms is designed for the leading mechanism of the control oil road. It can reduce the control performance of the control oil under the premise of reducing the pressure of the oil path. The problem of interference, especially the poor anti-interference ability of the gyroscope introduced for the first time, has developed a speed control system based on the new observer, which ensures better control performance under the abnormal working condition of the sensor. Finally, the hydraulic transformer control hydraulic cylinder system has coupling and strong nonlinear problems, and the design is designed. The controller with dynamic pressure feedback and fuzzy control does not need to pay attention to the internal structure of the system model, and improves the robustness of the speed control of the hydraulic cylinder.
At the end of this paper, the actual machine experiment and the bench simulation experiment are carried out. First, a data acquisition system is added to a 5T excavator based on LUDV principle, and the test of the standard working condition is carried out. The energy consumption analysis is carried out with the test data to verify the accuracy of the model. Then, the hydraulic pump / motor is directly driven by the engine and the overflow is used to overflow. The experiment of the forward compensating sliding mode controller which is proposed to increase the integral term is carried out in the way of the valve simulating the load. The results show that the algorithm can effectively improve the accuracy and robustness of the variable (variable pressure) mechanism position control system. The modification based on the principle of CPR is carried out on the rotary device, and the proposed formula is proved by the experiments of no load and heavy load. Then, the simulation experiment platform of hydraulic transformer to control the hydraulic cylinder is built, and the angle control and the position control experiment of the hydraulic transformer are carried out respectively. The experimental results show that the control method can complete the presupposition task, although the precision is not high, but it is suitable for the excavator for accuracy. Low engineering machinery field.
【学位授予单位】：哈尔滨工业大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TU621

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