【作者】 杜恒；

【导师】 魏建华；

【作者基本信息】 浙江大学 ， 机械电子工程， 2011， 博士

【摘要】 目前,在大型轮式车辆底盘油气悬架及电液控制转向系统方面仍然存在着一些亟待解决的问题,如油气悬架系统在车身姿态调整时无法实现整车的同步升降、多数油气悬架车辆在设计时未综合考虑平顺性和道路友好性的影响、电液控制转向系统多采用比例阀控制,转向性能不够理想,这些问题严重制约大型轮式车辆底盘的发展与应用,本文围绕上述三个问题,并以中联重科某型七桥全地面起重机为对象展开深入研究,具体内容如下：第一章,在查阅大量国内外有关油气悬架和电液控制转向系统研究文献的基础上,对具备车身姿态调整功能的油气悬架系统、油气悬架平顺性与道路友好性及其综合性能优化、电液控制转向系统这三部分的研究现状进行了综述,指出了各自存在的问题,并阐述了课题提出的意义及主要研究内容。第二章,对大型轮式车辆常用的连通式油气悬架各功能工作原理进行了分析,并讨论了连通式油气悬架升降不同步的机理,提出了一种基于调速阀和压力跟踪阀的连通式油气悬架同步升降系统并进行了分析,同时设计了该同步系统中的关键元件压力跟踪阀,建立了压力跟踪阀的数学模型与仿真模型,分析了各参数对压力跟踪性能的影响,并进行相应试验以验证模型的正确性,随后对单桥工况进行了同步升降系统的仿真与试验研究,并在实车上进行了整车同步升降试验,同步效果均较好,可满足大型轮式车辆底盘的实际需要。第三章,对油气悬架平顺性和道路友好性进行分析与优化,以整车七自由度动力学模型为基础分别建立路面谱模型和油气悬架系统的液压部分模型,并应用ADAMS、AMESim和Simulink对整车机构、油气悬架液压系统和路面谱进行了仿真建模和联合仿真分析,讨论了油气悬架主要刚度和阻尼参数对平顺性和道路友好性的影响规律,随后对平顺性和道路友好性进行归一化处理,应用遗传算法进行优化得出使油气悬架平顺性和道路友好性均较好的参数配置方案。第四章,针对大型轮式车辆转向系统的特点,设计了应用伺服比例阀的电液伺服转向系统,分别介绍了转向系统的功能、模式及工作原理,建立了系统转向机构的数学模型,并对其运动学和动力学进行了分析与简化,随后建立了液压控制系统的数学模型,将转向机构数学模型和液压控制系统模型结合后成为阀控双转向助力缸的电液伺服转向系统模型,对此模型进行了简化的线性化分析,讨论了各主要参数对电液伺服转向系统跟踪误差的影响规律,并指出跟踪误差会随着转向系统位置的变化而变化,转到左侧极限位置时跟踪误差最小,转到右侧极限位置时跟踪误差最大。第五章,对电液伺服转向系统进行联合仿真分析,基于ADAMS建立了转向系统机械部分模型,包括转向机构、轮胎和路面模型,基于AMESim建立电液伺服转向系统液压部分模型,并以AMESim为主控软件进行联合仿真分析,仿真结果表明跟踪误差与转向系统的位置有关,转到左侧极限位置时跟踪误差最小,转到右侧极限位置时跟踪误差最大,与理论分析结果一致,随后讨论系统主要参数如供油压力、比例环节增益、转向助力缸面积和泄漏、伺服比例阀频响、死区和滞环、管路长度和内径、载荷等对电液伺服转向系统性能的影响,并提出了一种变增益的控制策略,仿真结果表明这种控制策略可以有效抑制跟踪误差随转向位置变化,使跟踪误差趋于恒定。第六章,对电液伺服转向系统进行试验研究,介绍了试验台架及试验方案,并设计了基于LabVIEW的数据采集系统,首先基于试验台架进行静载试验分析,考察系统供油压力和比例环节增益对电液伺服转向系统的影响,并分别进行了空载与加载工况试验,试验结果与仿真及理论分析相吻合,然后基于中联重科某型七桥全地面起重机进行实车静载时的空载和加载工况试验,最后对实车进行行驶试验,各工况下电液伺服转向系统均能实现良好的转向性能,验证了所设计的基于伺服比例阀的电液控制转向系统的合理性与有效性。第七章,总结本论文的主要工作,阐述研究结论和创新点,并对大型轮式车辆油气悬架及电液伺服转向系统的后续研究作出了展望。更多还原

【Abstract】 Currently, there are still some problems to be solved in the hydro-pneumatic suspension and electro-hydraulic servo steering system of heavy wheeled vehicles. The urgent problems are described as follows:simultaneous movements of the vehicles in the body posture adjustment with hydro-pneumatic suspension can not be achieved, the majority of vehicles with hydro-pneumatic suspension are designed without taking into account road-friendliness and ride comfort comprehensively and the performance of the electro-hydraulic steering system with proportional valve is not satisfactory. The applications and development of the chassis in the heavy wheeled vehicles are seriously restricted by these problems. This paper focused on these three issues and the further study was carried out for the certain type of Zoomlion7-axles all-terrain crane. The main contents are as follows:In chapter1, on the basis of referring to a large number of domestic and international associated literatures about hydro-pneumatic suspension and electro-hydraulic control steering system, the body posture adjustment of the hydro-pneumatic suspension, integrated performance optimization of ride comfort and road-friendliness and electro-hydraulic control steering system were summarized. Their problems were pointed out. The related research background and significance of this subject was expounded and the main research work was proposed.In chapter2, every function of the commonly used interconnected hydro-pneumatic suspension in heavy wheeled vehicles was analyzed and the asynchrony mechanism was discussed. Based on flow control valve and pressure tracking valve, an improved interconnected hydro-pneumatic suspension was presented and lifting" synchronization of the system was realized. The key element pressure tracking valve of the synchronization system was designed. The mathematic model and simulation model of the pressure tracking valve were established and the effects of the various parameters on the performance of the pressure tracking valve were analyzed. The experimental research on the pressure tracking valve was performed and the model was verified correctly. The simulation and experiment were achieved on the one-axle condition of synchronized lifting system. The lifting synchronization experiment of the actual vehicle was performed and the synchronous effect was well. The improved synchronization system could meet the demand of high performance completely in the heavy wheeled vehicles.In chapter3, the ride comfort and road-friendliness of the hydro-pneumatic suspension were analyzed and optimized. Based on the whole vehicle7-DOFs dynamic model, road spectrum model and hydraulic system model in the hydro-pneumatic suspension were established. With the application of the ADAMS, AMESim and Simulink, the simulation model of the whole vehicle, hydraulic parts of hydro-pneumatic suspension and road spectrum was established and the co-simulation analysis was carried out. The effects of the main stiffness and damping parameters of the hydro-pneumatic suspension on ride comfort and road-friendliness were discussed. With the normalized processing of the ride comfort and road-friendliness, the appropriate configuration parameters of better ride comfort and road-friendliness were achieved by the genetic algorithm.In chapter4, according to the characteristics of heavy wheeled vehicle steering system, the electro-hydraulic servo steering system with servo-proportional valve was designed. The function, mode and working principle of the system were produced. The mathematic model of the steering mechanism was established and its kinematic and dynamic model were analyzed and simplified. Then the mathematic model of the hydraulic control system was established. These mathematic models could be combined as a valve-controlled two steering cylinders model. The simplified linear analysis of the combined model was achieved and the effects of main parameters on the tracking error of the electro-hydraulic servo steering system were discussed. The results show that the tracking error varies with the position of the steering system. The minimum tracking error appears at extreme left steering position while the maximum tracking error appears at extreme right steering position.In chapter5, the co-simulation of the electro-hydraulic servo steering system was analyzed. The simulation model of the mechanical parts including steering mechanism, tire and road was established based on ADAMS. The simulation model of the hydraulic parts was established based on AMESim. AMESim was set as master software and co-simulation analysis was achieved. The simulation results show that the tracking error varies with the position of the steering system. The minimum tracking error appears at extreme left steering position while the maximum tracking error appears at extreme right steering position. It is consistent with the theoretical analysis. The effects of the parameters of supply pressure, gain of the proportion link, area and leakage of the steering cylinder, frequency response, dead zone and hysteresis of the servo-proportional valve, length and diameter of the pipe and load on the performance of electro-hydraulic servo steering system were discussed. A kind of variable-gain control strategy was proposed. The simulation results show that this control strategy can effectively suppress the variation of the tracking error with steering position and the tracking error tends to be constant.In chapter6, experimental studies of the electro-hydraulic servo steering system were carried out, and the test bench and test scheme were introduced. The data acquisition system was designed based on LabVIEW. Firstly, the static experimental analysis based on test bench was carried out and effects of the parameters of supply pressure and gain of proportion link on the performance of the electro-hydraulic servo steering system were investigated. Tests on the unloaded and loaded conditions were carried out and the experimental results were consistent with the theoretical analysis and simulation analysis. Then, the static tests of a certain type of Zoomlion7-axles all-terrain crane on the unloaded and loaded conditions were carried out. Finally, the driving tests of the vehicle were also achieved. The performance of the electro-hydraulic servo steering system is good in all test conditions. It is verified that the designed electro-hydraulic servo steering system with servo-proportional valve is reasonable and effective.In chapter7, the major work of the study was summarized. The conclusions and innovations of the study were elaborated and the future study of the hydro-pneumatic suspension and electro-hydraulic servo steering system in heavy wheeled vehicles was also prospected.更多还原