| 果园钢索牵引货运系统负载纵向稳定性控制 |
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| 引用本文： | 杨洲,李伟,李君,李雪平,薛坤鹏.果园钢索牵引货运系统负载纵向稳定性控制[J].农业工程学报,2015,31(1):64-70. |
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| 作者姓名： | 杨洲 李伟 李君 李雪平 薛坤鹏 |
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| 作者单位： | 华南农业大学工程学院，广州 510642; 华南农业大学南方农业机械与装备关键技术教育部重点实验室，广州 510642 |
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| 基金项目： | 国家自然科学基金项目（51205139），广东省高等学校高层次人才项目（粤财教[2011]431号），国家科技支撑计划课题（2011BAD20B10-2） |
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| 摘 要： | 为有效抑制果园钢索牵引悬挂式货运系统吊重的纵向偏摆,该文采用根轨迹校正法设计了系统纵向运行稳定性控制器。在忽略侧向运动影响的前提下,利用拉格朗日方程建立了线性化的纵向动力学模型。通过在左半复平面添加2个零点,对系统的根轨迹进行了校正。仿真和试验结果表明:所提出的只考虑吊重在纵向平面内运动的数学模型能够表述原系统运动特性,设计的控制器可快速衰减纵向偏摆,抑制吊重纵向摆动角度在±1.5°以内,将摆角角速度幅度极值减小至10%。该研究为悬挂货运系统的纵向稳定性控制提供了参考依据。
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| 关 键 词： | 农业机械 运输 模型 悬挂货运系统 根轨迹校正法 稳定性控制 山地果园 |
| 收稿时间： | 2014/9/12 0:00:00 |
| 修稿时间： | 2014/12/2 0:00:00 |
Longitudinal stability control of orchard cable-driven hanging transport system |
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| Yang Zhou,Li Wei,Li Jun,Li Xueping and Xue Kunpeng.Longitudinal stability control of orchard cable-driven hanging transport system[J].Transactions of the Chinese Society of Agricultural Engineering,2015,31(1):64-70. |
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| Authors: | Yang Zhou Li Wei Li Jun Li Xueping and Xue Kunpeng |
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| Institution: | 1. College of Engineering, South China Agricultural University, Guangzhou 510642, China; 2. Key Laboratory of Key Technology on Agricultural Machine and Equipment, Ministry of Education, South China Agricultural University, Guangzhou 510642, China,1. College of Engineering, South China Agricultural University, Guangzhou 510642, China; 2. Key Laboratory of Key Technology on Agricultural Machine and Equipment, Ministry of Education, South China Agricultural University, Guangzhou 510642, China,1. College of Engineering, South China Agricultural University, Guangzhou 510642, China; 2. Key Laboratory of Key Technology on Agricultural Machine and Equipment, Ministry of Education, South China Agricultural University, Guangzhou 510642, China,1. College of Engineering, South China Agricultural University, Guangzhou 510642, China; 2. Key Laboratory of Key Technology on Agricultural Machine and Equipment, Ministry of Education, South China Agricultural University, Guangzhou 510642, China and 1. College of Engineering, South China Agricultural University, Guangzhou 510642, China; 2. Key Laboratory of Key Technology on Agricultural Machine and Equipment, Ministry of Education, South China Agricultural University, Guangzhou 510642, China |
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| Abstract: | Abstract: A cable-driven hanging transport system has the characteristics of labor saving, economic efficiency and good revenue, along with good prospect for increasing orchard utilization. Compared with the wheeled carrier and crawler, it can meet the demand of the complex mountainous topography. Both during and after transfer, the load motion of the hanging system can cause load swings, which is undesirable especially in the variations of acceleration. The longitudinal oscillations may lead to the instability of system and damage of agricultural goods. The aim of this paper is to develop an effective control method for the load motion that produces short travel time with suppressed load swing and satisfies operational constraints. Due to the nonlinearities of spatial three-dimensional motion of transferred load, the dynamics of the cable-driven hanging transport system showed complexity with coupled motion of load. In fact, the lateral movement had little effect on the longitudinal stability due to the low transport speed of cable and lager curvature radius of rails, which could be ignored in the development of plant equations. In order to effectively suppress the longitudinal load swings, the Lagrange equations were utilized and a mathematical model of the transport system was proposed. The transport system with multiple load masses in series can be considered as similar to the hoist system with a single concentrated load. The reason is that the distances between each hook point and mass center of load are at roughly the same value. As a result, the dynamic model of the transport system can be simplified to a linearized model by ignoring the effect of lateral movement and assuming the multiple load masses in series to be a single load mass. The state-space form of longitudinal equations of load motion was developed and its controllability and observability was analyzed. The system transfer function was obtained. From the performance specifications, a compensated controller with root locus correction was proposed by reshaping the root locus in order that the dominant closed-loop poles can be at desired locations in the complex plane. The damping ratio and natural frequency were specified. The designed procedure of root locus correction was achieved by adjusting the compensator pole and zeros with the addition of two zeros, which make the pole on the positive real axis move into the left half complex plane by eliminating the remaining zero at the origin plane. Because all the roots have negative real parts after reshaping the root locus, the closed-loop transport system was stable. The simulation and experimental results confirmed that the designed system was acceptable. The damping time was considerably reduced as compared with the original system without root locus correction. The stability of the transport system was guaranteed by the proposed controller with root locus correction for all values of gain, which can suppress the longitudinal swing angle within ±1.5° and reduce the maximum magnitude of in-plane swing angular velocity to 10% of that of the original system. In terms of the transporting time and process stability, the proposed control method can offer significant improvement in the actual operations of a hanging transport system. |
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| Keywords: | agricultural machinery transportation models hanging transport system root locus stability control hilly orchard |
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