【作者】 徐晓；

【导师】 管成；

【作者基本信息】 浙江大学 ， 机械设计及理论， 2012， 硕士

【摘要】 以液压蓄能器为储能元件的辅助式能量回收系统实现液压挖掘机回转制动能量的回收与再利用,是当前国内外工程机械领域的发展前沿课题。挖掘机作业时回转操作包含起动加速、匀速、减速制动三个连续的过程,其中在减速制动过程中能进行制动能量的回收。技术实现难点为：对减速制动阶段进入和终止的判定,在起动加速阶段液压储能器能量释放的控制。挖掘机回转制动能量回收液压辅助系统基于现有传统23吨级挖掘机平台展开研究。在不影响平台布局稳定性和尽可能少改动原有部件布置的前提下,提出了一种基于回转马达进/出口压力差实现回转马达起动加速与减速制动模式过程的液压自动识别与判断,决策系统进行制动能量回收的全液压自动控制系统。以蓄能器SOP(state of pressure)、液压泵出口压力与负流量反馈压力为输入信号,根据回转液压系统的实时需求功率,提出一种基于复合恒功率+负流量动力控制与正态分布函数的能量分配方法,综合决策液压泵与蓄能器两个主/辅动力源之间的能量分配比例,并保证挖掘机回转的操作习惯与性能。为保证控制器参数的合理性以及系统最高的节能率,引入了遗传算法对系统能量分配控制参数进行全局优化。结果表明,在回转转台单执行机构工作时,采用回转制动能量回收系统的液压挖掘机,能够实现再生制动能量回收利用率在50%左右,在同一工况下比同吨位挖掘机的节能率达到21%以上。更多还原

【Abstract】 Utilizing hydraulic accumulator based assistant energy recovery system is the key research program in the engineering machinery at home and abroad, which could achieve energy recycle and reuse during hydraulic excavator swing stage. Once the excavator starts to swing, it contains three continue phases as follows:start-up acceleration, constant speed, and braking deceleration. And partial energy could be recycled in braking deceleration phase. The technical difficulties are listed below:switch conditions of entering and exiting braking deceleration phase, energy release control in hydraulic accumulator in start-up acceleration phase.The swing braking energy recovery research is based on the traditional 23-ton excavator platform. No impacts on the platform layout stability and less change to the original system layout as premises, an automatic hydraulic-controlled braking energy recovery system was proposed which can automatically identify the swing stage by the pressure difference between inlet and outlet of the swing pump and determining distribution algorithm of the recovering energy. The state of pressure(SOP) of the accumulator, the outlet pressure of the hydraulic pump and the feedback pressure from negative-flow control were considered as inputs. According to the real-time required power of the swing hydraulic system, the energy distribution algorithm along with one normal school function were proposed based on the comprehensive constant-power negative-flow control. It distributes energy ratio between the main power source and the auxiliary power source (that is engine and accumulator). And it ensures the normal operation of the swing mechanism. To gain better system efficiency and more suitable parameter settings in the controller, the genetic optimization algorithm was utilized to optimize the system energy distribution parameters globally. Results show that the hydraulic excavator equipped with the swing recovery system can achieve more than 21% energy saving compared with the baseline under the same working condition, and the overall chain efficiency from the total braking energy to the terminal swing mechanism is as much as 50.0% approximately while the swing is utilized as the actuator alone.更多还原