基于联合仿真的双臂瓣形铲移树机性能分析与试验

Performance Analysis and Test of Dual Arm Petal Shaped Shovel Tree Digging Machine Based on Co-simulation

摘要:

针对我国丘陵山区林木种植密集、地形复杂导致的移树机适应性差、液压系统能效低等问题，对移树机动臂结构进行了设计以及液压缸选型，建立了移树机机-液-离散元联合仿真模型，对整机结构及液压系统性能进行了分析。采用Recurdyn软件，对移树机行走底盘以及动臂进行了动力学仿真，确定了移树机最大抬升负载质量为2t，动臂最大应力集中在抬升油缸孔前部，最大应力为72.5MPa。基于移树机机-液-离散元联合仿真模型，对移树机抬升工况、铲刀切削土壤工况、土球摆动工况进行了模拟计算，分析了各执行元件油缸内压力变化曲线以及铲刀切削土壤阻力变化曲线，仿真结果表明：机臂在抬升过程中，抬升油缸压力稳定，压力为5.2MPa；铲刀在切削土壤过程中，阻力逐渐增大，最大阻力为28900N；土球摆动工况下翻板油缸内压力随倾斜角度增大而增大，最大压力为8MPa。开展了移树机林地液压系统测试试验，测试结果表明：机臂抬升过程中抬升油缸压力稳定在5.5MPa；切削土壤工况下，铲刀油缸压力差为10MPa，间接计算得出切削阻力为28260N；土球摆动工况下，翻板油缸压力随倾斜角度增大而增大，最大压力为7.7MPa。通过移树机仿真试验与液压测试试验对比分析，得到抬升、切削土壤、土球摆动工况下仿真值与实测值相对误差分别为 5.5%、2.3%、3.9%，验证了移树机联合仿真模型准确性以及移树机动臂结构与整机液压系统的稳定性。

Abstract:

In response to the problems of poor adaptability of tree digging machines and low energy efficiency of hydraulic systems caused by dense forest planting and complex terrain in hilly and mountainous areas of China，the structure of the tree digging machine arm was designed and hydraulic cylinders model was selected，a co-simulation model of tree digging machine was established to analyze the structure and hydraulic system performance of the machine. Dynamic simulations were conducted on the chassis walking and arm of the tree digging machine using Recurdyn software. It was determined that the maximum lifting load of the tree digging machine was 2t. The maximum stress on the lifting arm was concentrated in the front of the lifting cylinder hole，with a maximum stress of 72.5 MPa. A co-simulation model of the tree digging machine-liquiddiscrete element method was established by using Recurdyn, AMESim, and EDEM software. The lifting condition of the tree digging machine，the soil cutting condition of the shovel, and the soil swinging condition were simulated and calculated. The pressure change curves inside the oil cylinder of each actuator and the soil cutting resistance change curve of the shovel were analyzed. The simulation results showed that during the lifting process of the arm，the pressure of the lifting oil cylinder was stable，with a pressure of 5.2 MPa. During the process of cutting soil，the resistance of the shovel was gradually increased, with a maximum resistance of 28 900 N. Under the condition of soil swing, the pressure inside the flap oil cylinder was increased with the increase of tilt angle, and the maximum pressure was 8 MPa. Testing on the hydraulic system of the tree digging machine in woodland was conducted, and the test results showed that the pressure of the lifting cylinder remained stable at 5.5 MPa during the lifting process of the arm. Under the condition of cutting soil，the pressure difference of the shovel cylinder was 10 MPa, and the indirectly calculated cutting resistance was 28 260 N. Under the swing condition of the soil, the pressure of the flap oil cylinder was increased with the increase of the tilt angle, and the maximum pressure was 7.7 MPa. Through comparative analysis of tree digging machine simulation experiments and hydraulic testing, the relative errors between simulation values and measured values under lifting, cutting soil, and soil swing conditions were found to be 5.5%，2.3%, and 3.9%, respectively. The accuracy of the cosimulation model of the tree digging machine and the stability of the tree digging machine arm structure and the hydraulic system was verified.