新型电驱动叉车举升系统及其节能效果分析

发布时间：2018-01-17 12:47

本文关键词：新型电驱动叉车举升系统及其节能效果分析　出处：《吉林大学》2017年硕士论文　论文类型：学位论文

【摘要】：叉车是起重、搬运机械之一,在港口、仓库等场合,物流、生产等领域发挥着重要作用。鉴于液压系统的比功率高、承载能力强、工作平稳、可靠性高,目前的主流叉车仍使用液压举升系统。但是由于液压系统在使用过程中涉及机械能、液压能之间的转换,而且介质在管路、液压阀中的能量损耗较为严重,因此液压举升机构的能量利用率较低。据工程实测数据,本文实验对象,叉车CPD30的能量利用率不足40%。换言之,超过60%的能量损失在做功过程中。当前,针对工程机械能量利用率的提高已经产生了许多方法,诸如:动、势能回收技术和混合动力技术等,但是此类高端技术需要依托高效的机械传动发挥作用。高效率的传动环节可以直接提高从原动机到执行端的能量利用率,还可以匹配以能量回收、混合动力系统,实现高水平的能量利用率。本文着眼于电驱动叉车举升机构传动效率提升,着重介绍了一种新型叉车举升系统,该系统以滚动螺旋副取代原液压缸举升系统,减小工作过程中的能量损失。滚动螺旋副的传动效率高达90%~98%,正、反向传动时都可以实现较高的能量利用率;而且滚动螺旋副不能自锁,这给反向传动过程中的能量回收提供了可能;加之滚动螺旋副的刚度大、传动精度高,在旋转运动和直线运动的转化过程中易于保证高响应速度和定位精度。为验证新系统的动力学性能、计算其能量损耗,需要为其建立动力学模型。机械传动系统的动力学模型使用功率键合图理论建立,并最终以系统状态空间表达式的形式呈现;新型举升系统选用了无刷直流电机作为原动机,无刷直流电机的动力学模型自MATLAB/Simscape的模型库中调用;无刷直流电机使用电流、转速双闭环系统进行调速,转速闭环中还使用了独立设计的基于模糊逻辑的PID控制方法。将机械传动系统的动力学模型、无刷直流电机及其控制器模型、叉车蓄电池模型联合起来,即可在MATLAB软件平台上进行仿真,用仿真得到的能量利用率和货叉的速度轨迹来评价新系统的工作表现。仿真结果显示:在动态特性方面,设计的丝杠举升系统能够很好地按照原叉车的设计要求保证货叉的举升速度、加速度;在节能效果方面,设计的丝杠举升系统在满载(3000kg负载)下的能量利用率高达56.23%,在1170kg载荷状态下为49.91%,在620kg载荷状态下为29.19%。为了验证使用滚动螺旋副的丝杠举升系统的可实现性,及其相较于液压举升系统的高效性,在叉车CPD30上进行了丝杠举升系统和液压举升系统的对照实验。结果显示,在多种载荷工况下,滚动螺旋副都有较高的能量利用率,在620kg载荷状态下,能量利用率达到31.56%,高过液压举升系统2.01%,在1170kg载荷状态下,能量利用率达到45.79%,高过液压举升系统7.45%。在动力学性能方面,在620kg载荷状态下,丝杠举升系统的平均举升速度比液压系统快0.018m/s,在1170kg载荷状态下,丝杠举升系统的平均速度比液压系统快0.003m/s。本文以仿真的方式估算了丝杠举升系统的能量利用率;对比于液压举升系统,以实验的方式验证了丝杠举升系统的动力学性能和节能效果。本文证实了新系统的开发潜力,为以后的高效系统开发提供了更好的机械平台,为其他工程机械的改型研发提供了参照。
[Abstract]:The forklift is lifting, handling machinery in one of the ports, warehouse and other occasions, logistics, production and other fields play an important role. In view of the hydraulic system of high specific power, strong bearing capacity, stable operation, high reliability, the current mainstream forklift still use hydraulic lifting system. But because the hydraulic system relates to mechanical energy in the process of using in the conversion between the hydraulic energy, and medium in the pipeline, the energy loss in the hydraulic valve is more serious, so the hydraulic lifting mechanism of the energy utilization rate is low. According to the measured data, the experimental object, CPD30 forklift the energy utilization rate of less than 40%. in other words, more than 60% of the energy loss in the work process. At present, to improve the energy efficiency of construction machinery has produced many methods, such as: dynamic, energy recovery technology and hybrid technology, but such high-end technology need to support the efficient mechanical transmission The essential role of transmission efficiency. From the original motivation to perform terminal energy utilization directly improve, also can match with energy recovery, hybrid power system, to achieve a high level of energy efficiency. This paper focuses on the electric forklift lifting mechanism to enhance the transmission efficiency, emphatically introduces a new type forklift lifting system, the system to replace the original ball screw cylinder lifting system, reduce the energy loss in the working process of screw rolling. The transmission efficiency is as high as 90%~98%, and can achieve high energy utilization rate of reverse transmission; and the ball screw can not lock, which gives the energy recovery in the process of reverse transmission may be provided; and rolling screw pair of stiffness, high precision, easy to ensure high response speed and positioning accuracy in the transformation process of rotary motion and linear motion. In order to verify the new system dynamics The performance calculation of the energy loss, need to establish a dynamic model for the dynamics model of mechanical transmission system using power bond graph theory is established, and the state space expression of the form; new type of lifting system uses a brushless DC motor as the prime mover, called model base dynamic model of Brushless DC motor MATLAB/Simscape the brushless DC motor; current and speed double closed loop control system for speed, speed loop are used in independent design of the fuzzy logic control method based on PID. The dynamic model of the mechanical transmission system, brushless DC motor and its controller model, forklift battery models are combined, can be simulated on the platform of MATLAB software the performance evaluation system, to the new speed track rate and fork of the use of energy simulation. The simulation results show that the dynamic characteristics Of hand, screw lifting system design can be well in accordance with the original design requirements to ensure forklift fork lifting speed and acceleration; the effect of saving energy, the design of screw lifting system in full load (3000kg load) under the high energy utilization rate reached 56.23%, in the 1170kg under load is 49.91% 620kg in load state under the 29.19%. in order to verify the feasibility of the use of ball screw screw lifting system, and its efficiency compared to the hydraulic lifting system, the control experiment of screw lifting system and hydraulic lifting system of the forklift in CPD30. The results show that under different loads, ball screw has high energy utilization rate in 620kg, under load, the energy utilization rate of 31.56%, higher than 2.01% in 1170kg hydraulic lifting system, load condition, the energy utilization rate of 45.79%, higher than the hydraulic lifting system in 7.45%. power School performance, in the 620kg under load, the average lifting speed of screw lifting system than hydraulic system. 0.018m/s, 1170kg in the load condition, the average speed of screw lifting system of hydraulic system based on the 0.003m/s. than the fast simulation method to estimate the screw lifting system of energy utilization; compared to the hydraulic lifting system, dynamic performance and energy saving screw lifting system was validated by the experimental method. This paper proves that the new system development potential, provides a better platform for the development of efficient mechanical system for the future, provide a reference for other research. Modification of engineering machinery

【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH242

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