【作者】 韩庆珏；

【导师】 刘少军；

【作者基本信息】 中南大学 ， 机械工程， 2014， 博士

【摘要】 摘要：履带式行走机构由于其自身特殊的结构特点经常被应用在军事、农业以及采矿领域。对于深海多金属结核及钴结壳采矿而言,众多国家都相继研制出了海底履带式采矿系统。履带式集矿机作为深海采矿系统的关键子系统,其作业环境下的运动控制问题成为研究热点。集矿机行走在海底极其稀软的底质上,其行走动力来自于履带与海底软底质之间的相互剪切作用。由于软底质固有的土力学特性,集矿机海底作业过程中履带会产生一定的打滑作用,打滑率的变化将直接影响到集矿机海底行走动力性能。同时,集矿机海底作业过程需按照预先设定路径进行开采行走。但由于受到布放偏差、海底软底质、洋流等作用的影响,集矿机实际行走路径与预定路径存在一定的偏差。为保证集矿效率,路径跟踪问题成为集矿机作业过程关键运动控制问题之一。对深海采矿系统而言,为保证整体系统的稳定性,集矿机与采矿船之间的随动控制问题也尤为关键。本文针对上述三种关键运动控制问题,提出了相应的控制策略和算法,并通过仿真和实验验证了算法的可行性和正确性。论文主要研究成果如下：1.以履带车辆地面力学特性研究为理论基础,利用以膨润土和水的混合物作为海底模拟软底质,推导出海底稀软底质压力—沉陷关系和剪切应力—剪切位置关系计算公式,建立了集矿机驱动力与打滑率之间的关系。通过对集矿机行走过程各运动阻力的分析,建立了完善的集矿机力学和运动学模型。提出了方便研究的简化力学模型,并对简化可能导致的误差进行了分析,为履带式集矿机运动控制研究提供了理论基础。2.基于驱动力与打滑率之间的关系,提出了匀底质条件下最佳打滑率判断标准。通过对集矿机牵引效率分析,建立了非匀底质条件下最佳打滑率辨识方法。建立了履带式集矿机液压驱动模型,通过仿真验证了模型的正确性。提出了模糊PID打滑控制策略,建立了打滑控制系统模型。通过对匀底质和非匀底质条件下打滑仿真结果的分析,证明了控制策略的有效性和稳定性。3.通过对集矿机路径跟踪控制问题的描述,建立了集矿机路径偏差模型。综合考虑了集矿机行走动力约束、跟踪路径平滑性以及跟踪时间最优三个因素,提出了以三次样条曲线为跟踪路径的时间最优控制策略。通过构造李雅普诺夫函数,提出了满足算法稳定性要求,针对由于布放偏差导致的算法不稳定的四种情况,提出了相应的控制策略。建立了路径跟踪控制系统模型,通过对同一路径不同跟踪系数仿真结果对比分析,确定了0.66为最佳路径跟踪系数。通过对直线、圆形、实际开采路径的跟踪控制仿真结果分析,验证了控制算法的正确性。通过与PID控制算法的仿真结果的对比,验证了算法的时间最优特性。4.以我国中试1000m海试总体方案为研究基础,分析比较了横纵两种折返作业方式的优缺点。出于整体系统运动复杂性以及对海底环境破坏等因素的考虑,确定纵向折返为整体系统折返方式。分析了整体系统中采矿船、中间仓、集矿机各自的运动安全域,考虑到输送软管马鞍构形的要求,最终确定采矿船与集矿机投影水平距离240m为整体系统联动控制目标。建立了整体联动控制系统,并分别在顺流和逆流条件下对整体系统联动进行了仿真,仿真结果表明整体系统能够满足控制要求。5.进行了集矿机打滑及路径跟踪控制实验。利用沙土与水的混合物作为模拟软底质,通过对比不同配比比例下混合物力学特性,最终确定砂水最佳比例为1.5：1。通过6组打滑牵引实验验证了理论推导方法的正确性。通过跟踪直线、圆形以及开采路径三次实验,验证了路径跟踪算法的可性能与正确性。更多还原

【Abstract】 Abstract:Due to its particular structural feature, tracked vehicles are widely used in military, agricultural and mining applications. For the deep sea mining task, mining research using a tracked miner system has been conducted in many countries. As an indispensable subsystem of the whole deep sea mining system, the operating motion control of the tracked miner is becoming a research focus.Because the tracked mine goes on the extremely cohesive sediment, the traction force is provided by shear stress which is caused by the shear displacement of the track. Because of inherent soil mechanics of the sediment, slippage under the track will be produced when the miner walks on the soil, and the change of the slip rate will affect the dynamic behavior of the miner. Since the working path of the miner is planned ahead, the trajectory of tracked miner in the real working condition can hardly go with the desired path. To ensure mining productivity, path tracking serves as one of the critical operating motion control. To guarantee the stability of the whole integrated deep sea mining system, follower control between the miner and the ship is also of great essence. In this paper, these three motion control problems are concerned and proper control strategies and algorithms are proposed. After a series of simulation tests and experiments, the feasibility and validity of the algorithms has been confirmed.The main research achievements are as follows:1. Based on the terrain mechanics of the tracked vehicle, a calculation formula, which reflects the relationship both the pressure and sinkage as well as the shear stress and shear displacement, is established. Also the relationship between the traction force and the slippage is set up.By analysis of the motion resistance, a thorough dynamic and kinetic model of the tracked miner is established. To avail the research, a simplified dynamic model is proposed and the error coming along is analyzed. From the theoretical respect, all these work facilitates the motion control of the miner.2. According to the relationship between the traction force and slippage, judging criteria of optimal slippage, which based on homogeneous soil, is put forward; also a method to identify the optimal slippage under non-homogeneous soil is established. To better control of slippage of the miner, a fuzzy PID control strategy and a model of slip control system is developed. By a series of simulation under both homogeneous and non-homogeneous soil condition, the effectiveness and stability of the strategy is testified.3. The difficulty of the path tracking control is described and the deviation model of the path tracking of the miner is developed. By taking the dynamic constrain of the miner, the smoothness of the trajectory and the time-optimal method into consideration, a time-optimal control strategy, which is based on the cubic spline curve, is proposed. Via Lyapunov method, the stability of the algorithm has been proven. For the instability situations resulting from the deploying process of the miner, the corresponding control tactics are developed. Also, the model of the path tracking control system is established. By analysis of the simulation results, the optimum coefficient, which value is0.66, is determined. After a series of tracking simulation under straight path, circular path and actual mining path, the validity of this control strategy is testified. Comparing with the PID control algorithm, it turns out that the proposed algorithm has a better time-optimal feature.4. According to the total system design for the1000m sea trial project, two operating paths are contrasted, which are longitudinal and transverse. A distance of240m between the miner and the ship is chosen as the objectives for the integrated motion control of the whole system. Then a series of simulation both under fair current and counter current has been done. From the result of the simulation, the strategy can satisfy the control requirement.5. A series of experiments concerning the critical motion control have been conducted. In the experiments, mixture of the bentonite and the water is used as the simulated sediment. By measuring the mechanical property under different ratio of bentonite and the water, the optimal ratio is determined, that is1.5:1. According to the results from six group traction-slippage tests, the theoretical derivation method is verified. Through path tracking experiments, it indicates that the testing miner can moving along the desired path accurately, thus the correctness and the credibility of the simulations of path tracking can be verified.更多还原