新型混联式汽车电泳涂装输送机构的PD滑模控制研究

发布时间：2017-12-28 15:58

本文关键词：新型混联式汽车电泳涂装输送机构的PD滑模控制研究　出处：《江苏大学》2017年硕士论文　论文类型：学位论文

【摘要】：现有汽车电泳涂装输送系统,如Rodip输送机和多功能穿梭机等皆采用悬臂梁结构,存在着柔性化水平不高、承受重载荷、大载荷的能力较差的问题。针对上述问题,本课题组在国家自然科学基金项目(51375210)资助下,研制了一种新型混联式汽车电泳涂装输送机构。该输送机构兼具串联机构和并联机构的特点,其结构简单、承载能力强、柔性化水平高、应用领域更广。该输送机构由多条运动支路组成,在机构运行过程中,由于其具有高度非线性、强耦合、时变参数等特性,并存在未知扰动等,对其进行高性能控制较为复杂。为保证输送机构平稳、可靠运行,有必要对其控制算法进行研究。在现有控制算法中,滑模控制对外界干扰不敏感,具有较强鲁棒性,但是滑模控制等效控制项的设计依赖于系统精确的动力学模型。由于系统存在参数不确定、未知扰动、模型误差等不良因素,建立其精确的动力学模型往往比较困难。滑模切换项通过大开关增益可以解决模型依赖问题,但过大的开关增益又会引起系统抖振,影响系统的控制性能。PD控制因其结构简单、易于操作和实现,并且不依赖被控对象的数学模型,因而在机器人控制和工业过程控制中得到了广泛应用。但对于模型不确定、非线性和多变量的被控对象,PD控制往往难以实现高性能控制。为此,为解决输送机构存在的模型不确定性对滑模控制性能的不良影响,本文针对输送机构提出一种PD滑模控制方法,以减小滑模控制对动力学模型的依赖,提升PD控制在高速运动控制中的动态性能,进而提高输送机构的控制精度。在此基础上,为进一步提高系统的鲁棒性,同时削弱系统抖振,对于所提出的PD滑模控制方法,通过引入时延估计方法对动力学模型非线性部分近似线性化估计以消除系统存在的非线性对控制性能的不利影响,基于线性化动力学模型提出一种基于时延估计的PD滑模控制方法。此外,本文设计的基于时延估计的PD滑模控制器含有PD参数和滑模参数,由于参数较多,如何减少参数选取的工作量也是一个重要问题,因此本文在用Lyapunov方法对其稳定性证明的过程中得到一组关于控制器参数的线性矩阵不等式,由该线性矩阵不等式组可以确定控制器参数在满足稳定性条件下的范围,为控制器参数的选择提供了依据,大大减少了控制器参数选取的工作量,具有较高的工程实用价值。本文首先对汽车电泳涂装输送设备发展、混联机构及其控制算法研究现状进行了概述;接着,针对输送机构建立运动学逆、正解模型、Jacobi矩阵,在此基础上采用Lagrange法进一步建立机构动力学模型,并用MATLAB对其运动学、动力学模型进行仿真,结果表明了运动学分析的正确性及动力学分析的可靠性;然后,为解决传统滑模控制的控制效果对精确动力学模型的依赖问题,针对输送机构设计了一种PD滑模控制器。另外,为进一步解决系统存在的非线性对PD滑模控制的不利影响,通过引入时延估计方法,针对输送机构设计了一种基于时延估计的PD滑模控制方法,并用MATLAB进行仿真,仿真结果表明了该控制器比传统的滑模控制器,不仅具有更高的轨迹跟踪精度,更强的鲁棒性,还削弱了传统滑模存在的抖振现象,具有较优的综合控制性能。最后,根据控制要求,采用“上位机“PC+下位机UMAC”的分布式结构构建了输送机构实验平台,给出了输送机构样机装机调试方案,解决了输送机构样机调试中出现的故障并给出了其诊断过程,并基于该实验平台完成了输送机构控制实验。实验结果进一步验证了本文所设计基于时延估计的PD滑模控制方法的可行性和有效性。
[Abstract]:The existing automotive electrophoretic coating and conveying systems, such as Rodip conveyor and multifunctional shuttle machine, all adopt cantilever structure, which has the problem of poor flexibility, heavy load and heavy load. Under the support of the National Natural Science Foundation of China (51375210), we have developed a new type of hybrid electrophoretic coating transport mechanism. The conveying mechanism has the characteristics of series mechanism and parallel mechanism, which is simple in structure, strong in carrying capacity, high in flexibility and widely used in the field of application. The transport mechanism is composed of several moving branches. In the process of mechanism operation, because of its highly nonlinear, strong coupling, time-varying parameters and unknown disturbances, its high performance control is more complex. In order to ensure the smooth and reliable operation of the transmission mechanism, it is necessary to study its control algorithm. In existing control algorithms, sliding mode control is not sensitive to external disturbances, and has strong robustness. However, the design of equivalent control of sliding mode control depends on the accurate dynamic model of the system. It is difficult to establish an accurate dynamic model of the system because of the bad factors such as uncertainty of parameters, unknown disturbance, model error and so on. The sliding mode switching term can solve the model dependence problem through the large switching gain, but the oversized switch gain will cause the system buffeting, which affects the control performance of the system. PD control is widely applied in robot control and industrial process control because of its simple structure, easy operation and implementation, and does not depend on the mathematical model of controlled object. However, PD control is often difficult to achieve high performance control for uncertain, nonlinear and multivariable controlled objects. Therefore, in order to solve the transport mechanism uncertainties the bad influence on the performance of sliding mode control, this paper proposes a conveying mechanism of the PD sliding mode control method to reduce the dependence on the kinetic model of sliding mode control, improve the dynamic performance of PD control in high speed motion control, and improve control precision of conveying mechanism. On this basis, to further improve the robustness of the system, at the same time reduce chattering, PD for the proposed sliding mode control method, by introducing a time delay estimation method to estimate the approximate linear dynamic model of nonlinear part to eliminate the system nonlinearity to control the adverse influence of the ability of the linear dynamic model of a PD sliding mode the control method based on time delay estimation. In addition, this paper designs the PD sliding mode controller based on time delay estimation with PD parameters and mode parameters, as more parameters, how to reduce the workload of parameter selection is an important problem, get a set of controller parameters on the linear matrix inequality in this paper to prove its stability in the process of using the Lyapunov method, the linear matrix inequality group can determine the parameters of the controller to meet the stability conditions, provide the basis for the selection of the controller parameters, greatly reducing the workload of the controller parameter selection, and has high practical value. Firstly, electrophoretic coating and conveying equipment development, research status of hybrid mechanism and control algorithm are summarized; then, according to the transport mechanism of inverse model, Jacobi matrix, positive solutions on the basis of kinematics, further establish the mechanism dynamics model by Lagrange method, and the kinematics and dynamics model using MATLAB simulation, results show that the correctness and reliability analysis of dynamics and kinematics analysis; then, in order to solve the control effect of the traditional sliding mode control for precise dynamic model of the dependence problem in the design of conveying mechanism of a PD sliding mode controller. In addition, in order to further solve the system of nonlinear adverse effects on the PD sliding mode control, by introducing a time delay estimation method for the design of conveying mechanism of a PD sliding mode control method based on time delay estimation, and using MATLAB simulation, the simulation results show that the controller than conventional sliding mode controller, not only has higher tracking accuracy the trajectory of more robust, also weaken the chattering phenomenon existing in traditional sliding mode, has better performance is. Finally, according to the control requirements, the distributed structure using "PC" PC+ machine UMAC "constructed conveying mechanism experimental platform, gives the transfer mechanism prototype installed debugging scheme, to solve the transport mechanism of prototype debugging appears and gives the fault diagnosis process, and based on the experimental platform to complete the control mechanism of transport experiment. The experimental results further verify the feasibility and effectiveness of the proposed PD sliding mode control method based on time delay estimation.
【学位授予单位】：江苏大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U468.2;TP273

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