【作者】 唐建林；

【导师】 赵克定；

【作者基本信息】 哈尔滨工业大学 ， 机械电子工程， 2009， 博士

【摘要】 随着半实物仿真技术的迅速发展,运动模拟器被广泛应用于航空、航天、航海、车辆及娱乐等军用和民用领域的产品开发以及驾驶员训练过程中。液压六自由度运动平台因其具有刚度大、推重比高及模拟出各种空间运动姿态等优点而被应用于绝大部分运动模拟器的运动系统。由于液压六自由度运动平台的动态性能直接关系到运动模拟的逼真度,而先进的运动控制是实现良好动态性能的关键技术之一。因此,深入地研究液压六自由度运动平台的控制策略及其相关的参数辨识方法,以提高液压六自由度运动平台的动态响应性能具有十分重要的意义。在查阅大量国内外有关文献的基础上,概述了液压六自由度运动平台的结构与特点,阐述了国内外液压六自由度运动平台的应用与发展概况,全面综述了液压六自由度运动平台关键技术研究现状,提出了论文主要研究内容。机械系统动力学模型是研究液压六自由度运动平台控制策略的重要组成部分。首先,基于考虑液压缸惯性影响的完整动力学模型,分析了液压缸惯性以及动力学模型中各项在各种工况下对驱动分支出力的影响,以简化动力学模型结构;然后对液压六自由度运动平台的动力学模型结构进行了分析,将液压缸惯性对动力学方程的影响等效为上平台惯性参数的变化,建立了以平台惯性参数为变量的线性化动力学方程,为运动平台参数辨识与基于模型的控制策略研究奠定了基础。准确的模型参数是研究液压六自由度运动平台控制策略的基础。为了辨识整个系统的模型参数,将系统模型分为液压驱动模型部分和机械负载模型部分。为得到液压驱动模型参数,建立了液压六自由度运动平台液压驱动分支非线性模型的辨识模型和验证模型,采用遗传算法作为辨识方法,获得了液压驱动模型参数并经实验数据验证了所辨识参数的正确性;针对机械负载模型部分,提出了采用多步法结合动力学滤波技术进行惯性参数辨识,解决了常规辨识方法难于辨识的问题。通过两部分辨识得到了整个液压六自由度运动平台模型的全部参数,为后续基于非线性模型的控制器设计提供了模型参数依据。作为液压六自由度运动平台的关键技术,本文集中研究了基于关节空间和任务空间的控制策略以解决不同应用环境中的控制问题。首先针对液压六自由度运动平台工作过程中驱动分支参数摄动量大和负载大范围变化等问题,基于李雅普诺夫稳定性,提出了一种基于关节空间非线性模型的反步自适应控制策略,该控制策略对动力学干扰力进行了补偿,通过引入动态面避免了加速度反馈,仿真结果表明其有效地抑制了系统参数大范围摄动、关节间的动力学干扰力以及外界干扰的影响,提高了液压六自由度运动平台的控制跟踪性能。其次针对液压六自由度运动平台工作过程中动力学交联耦合和参数不确定性等问题,基于李雅普诺夫稳定性,提出了一种基于任务空间非线性模型的反步自适应控制策略,该控制策略基于系统的完整非线性动力学模型,适用于全工作空间,通过引入动态面避免了加速度反馈,仿真结果表明其有效地抑制了系统参数不确定性、动力学非线性与自由度间交联耦合的影响,改善了系统的动态性能,提高了系统的跟踪能力。最后,对所研究的内容在液压六自由度运动平台上进行实验研究,并对实验结果进行分析验证了理论分析、参数辨识以及控制策略的正确性。结果表明,相比常规的控制器,所提出的关节空间自适应控制和任务空间自适应控制策略能更有效地抑制动力学耦合力,提高了六自由度运动平台的动态性能。更多还原

【Abstract】 Along with the rapid development of Hardware-in-loop simulation technology, motion simulators are widely used military and civil fields such as in aeronautics, astronautics, maritime, vehicle and amusement, etc for their production development and training. The six-dof (six-degree-of-freedom) hydraulic motion platform is used as a motion system for almost all motion simulators for its advantages such as high stiffness, high power density and capable of simulating all space movements, etc. The dynamic performance of the six-dof hydraulic motion platform has a direct relationship with the degree of versimilitude in motion simulation, and the advanced movement control strategy is one of the most key technology to realize the best dynamic performance.Therefore, a widely and in-dept research on the control theory and parameter identification for the six-dof hydraulic motion platform to improve the performance has a great significance.Base on the large amount of relative references at home and abroad, this paper outlined the architecture and characteristics of the six-dof hydraulic motion platform, depicted its developing status and application. In the meantime this paper summarized the key technology for the six-dof hydraulic motion platform, and then put up the main study content of the whole paper.The mechanical dynamics model is an important research area of the control strategy for the six-dof hydraulic motion platform. First of all, after the setup of the mechanical dynamics model including the leg’s influence, the influence of the leg and each part of the dynamics equation to driving force was analyzed to simplify the architecture of the dynamics model. The expression of the dynamics model was also analyzed to draw such a conclusion that the leg’s inertia and moment can be seen as an equivalent increment of the upper platform, and then derived an linearized dynamics equation expressed by the vector of the upper platform’s inertia parameters, which paved the way to give an research on to the parameter identification and model-based controller design.Accurate value of the model parameter is a prerequisite for control strategy research. To identify all the model parameters for the whole system, the system model is divided into two parts: hydraulic model part and mechanical load part. The identification model and the validation model for hydraulic nonlinear drive model are setup. The genetic identification method was used to identify the hydraulic nonlinear model parameters. The experimental data validates the effectiveness of the identification method. As far as the mechanical dynamics parameters were concerned, a step by step identification method combined with dynamic filtering technique was proposed to identify the inertia parameters to overcome the disadvantages of the difficult design and reach of optimum trajectory for identification. All parameters of these two parts from the identification provided the basis for for model-based nonlinear controller’s design.As a key technology of the six-dof hydraulic motion platform, this paper mainly studied the joint-space contrller and task-space controller to cater for the application in different circumstances.Aim to solve the problem of the leg’s large parameter perturbation and load changes during the work of the hydraulic six dof motion platform, a backstepping adaptive controller based on joint-space nonlinear model was proposed according to Lyapunov stability.The proposed controller compenated the dynamic coupling force and avoided the acceleration feedback by introducing the dynamic surface. The simulation results indicated that it can effectively suppress the influence from large parameter variance, dynamics coupling force among legs and external disturbance. The dynamic performance of the six-dof hydraulic motion platform was improved. As to deal with the dynamic cross-coupling force and parameters uncertainties, a backstepping adaptive controller based on task-space nonlinear model was put forward according to Lyapunov stability. The proposed controller was capable for everywhere in workspace for it is constructed on the basis of the complete nonlinear dynamics model, and avoided the acceleration feedback by introducing the dynamic surface. The simulation results indicate that it can effectively restrain the influence from parameter uncertainties, dynamics nonlinearity and load cross coupling among degrees. The dynamic performance was improved to attain a better tracking ability.At last, the experimental research was carried out on the six-dof hydraulic motion platform. The experimental results were analyzed. It validated the correctness of the theory analysis and parameter identification. It is shown that compared with the ordinary control methods, the proposed two controllers,namely the joint-space and task-space adaptive controller can more effectively depress the dynamic coupling force and thus improve the dynamic performance of the hydraulic six dof motion platform.更多还原