装载机工作装置斗尖载荷当量模型与试验
Bucket tip load equivalent model and experiment on loader working device

为获得装载机工作装置在铲装作业过程中外载荷的时间历程，进行了载荷谱编制与疲劳台架试验，提出一种由铲斗铰接孔处载荷当量装载机工作装置铲斗斗尖载荷的计算方法。在铲斗上建立随体坐标系，通过D-H(Denavit-Hartenberg)矩阵得到铲斗随体坐标系与大地坐标系之间的转换关系，根据油缸位移确定装载机作业姿态，进而由铲斗受力模型求得固定姿态下斗尖处的当量载荷理论解；设计了销轴传感器，并进行标定试验得到销轴传感器各个方向外载荷与电桥输出电压之间的线性函数关系；建立包括销轴力、侧向力、拉杆力、动臂关注点应力、动臂油缸和铲斗油缸位移的多参数载荷同步测试系统，并进行散状物料铲装试验，得到铲斗随体坐标系下铰点销轴力、结构测点应力和油缸位移等基本载荷参数；在此基础上，以铲斗斗尖当量载荷为外载，进行了工作装置有限元分析；验证了载荷当量模型和所得结果的合理性。研究结果表明：由实测载荷参数和斗尖载荷当量模型能得到反映装载机工作装置铲斗斗尖处真实受力特性的当量载荷时间历程，且载荷当量时间历程呈明显的周期变化，大载荷出现在铲掘物料和卸载物料时刻；动臂结构测点应力的仿真值与试验实测值之间最大相对误差为9.07%，将大小和方向连续不断变化的销轴载荷当量到固定姿态下的铲斗斗尖处，为装载机工作装置载荷谱编制和疲劳试验提供依据。
In order to obtain external load time history of loader working device in shoveling process, load spectrum compilation and fatigue bench test was carried out, and calculation method through bucket hinge hole loads to equal bucket tip load was proposed. The moving coordinate system was established on the bucket. The transformation relationship between the moving coordinate system and the geodetic coordinate system was obtained by the D-H(Denavit-Hartenberg) matrix. The operating postures of loader were determined according to the displacement of cylinder. Theoretical solutions of the equivalent loads at bucket tip were obtained by mechanical force model of the bucket under fixed stance. A pin axis sensor was designed, and the linear function relationship between external load and output voltage of the bridge in all directions was obtained through the calibration test. The multi-parameter load synchronous test system was established which include pin axial force, lateral force, pull rod force, boom structural stress, boom cylinder and bucket cylinder displacement. Through the shovel loading test, the basic load parameters in coordinate system fixed on the bucket such as pin force, structure measuring point stress and oil cylinder displacement were obtained. Based on the basic load parameters, finite element analysis of the working device was carried out with the equivalent load of bucket tip as outside load. The results show that the equivalent load time history can be obtained through the measured load parameters and the bucket tip load equivalent model which can reflect the real force characteristics of the bucket tip in the loader working device. The bucket tip load time history exhibits marked periodic variations. The large load appears at the time of shoveling and unloading particle material. The maximum relative error between the simulated value and the measured value of the boom structure is 9.07%. The pin load with continuous change in size and direction is equivalent to the bucket tip under