【作者】 沈伟；

【导师】 姜继海；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2014， 博士

【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。更多还原

【Abstract】 The increasing energy crisis and environmental deterioration phenomenon is becoming the key problem for preventing the healthy development of the world. The energy saving research for excavators is not only benefit for reducing the energy consumption, but also making an example for other type construction machines. Moreover, the hydraulic hybrid technique is promising because the high power density and the energy recuperation potential. However, the state of the art about this technique is mostly constrained with the sub system, esplecially lack of the control strategy or the performance research from the whole aspect. Hence this technique is not popular until now. Based on the project of “key technological research on the energy-efficient hydrostatic hybrid system” supported by National Natural Science Foundation of China, this paper focuses on the hydraulic hybrid excavator based on CPR and invistages the whole machine design and the key problems during the practical process.Firstly, the characteristics between the hydraulic and the electric hybrid excavators are analyzied by introducing the exact model based on the state of the art of the hybrid excavators. Then, the hydraulic hybrid excavator based on CPR is chosen as the research object and the development of the technique is stated. Furthermore, the Hydraulic Hybrid Excavator based on Common Pressure Rail combined Switched Function is presented and the principle is explained. The whole machine model is constructed by using the theory analysis combined with the test rig testing method for the critical components. And the matching process of the new elements is finised. Then, some critical parameters are necessary for simulation but hard to get, such as the friction coefficient and the rotational inertia, are identified by using the single testing of the arm, and the compound control action is used to prove the result. Moreover, the optimal mataching for the critical elements is analyzied by using the dynamic programming algothim under the minimum fuel consumption object during the standard cycle.The new system can save the oil consumption as37%by comparing the original LUDV excavator. Furthermore, the method by using lower relief pressure is presented after analyzing the energy distribution of the new excavator. Moreover, the hierarchical controller combined with control strategy and control method is designed, especially three kinds of practical control strategies are studied for the middle layer and the ASPS is the best one.The FSMI controller is designed to enhance the performance under the lower pilot control pressu caused by adopting the energy saving control stragety. For the new sensor which is easy to disturb, especially for the gyro, the observe-based controller is investigated and the result shows that the control performace is acceptable even under the condition while the sensor fails. Finally, because the cylinder controlled by the hydraulic transformer has the strong coupling and nonlinear problem, the controller combined the active pressure feedback and fuzzy principle is presented to enhance the robust performance without concering the interior structure.In the end of the thesis, both the test rig and the prototype machine experiments are conducted. Firstly, the original5t excavator is modified by adding the data acquisition system and the standard working cycle is tested to prove the simulation result for the energy distribution analysis. Moreover, the swash plate position experiment by using the method, that the engine drives the pump/motor and the relief valve is simulated as the load, is finised to test the effictiveness of the control algorithm. Then, the swing is modified according to the CPR theory and the feasibility is tested under the conditions of light load and overload respectively. Furthermore, the test rig for the cylinder controlled by the hydraulic transformer is constructed. The experiment including angle control of the port plate and the position control of the cylinder is tested, the result shows the method can complete the task in spite of the accuracy is low, however, it is appropriate for the construction machine such as excavators because this kind of machines does not require the high accuracy.更多还原