| 题名 | 高精度机载光电平台视轴稳定技术研究 |
| 作者 | 魏伟 |
| 学位类别 | 博士 |
| 答辩日期 | 2015-05 |
| 授予单位 | 中国科学院大学 |
| 导师 | 戴明 |
| 关键词 | 等效扰动 波动力矩 LuGre模型 自抗扰控制器 重复控制器 |
| 其他题名 | The Research of optical axis stabilization of the Airborne Photoelectric Platform |
| 学位专业 | 光学工程 |
| 中文摘要 | 高精度机载光电稳定平台目前广泛应用在国防军事领域中对于空中即地面军事目标的捕获、跟踪以及瞄准任务。其中，视轴稳定精度是衡量平台性能好坏的最关键的一项技术指标，视轴稳定精度越高，光电载荷的成像质量就越高，平台的稳定性能也就越高。然而，在飞机飞行过程中，光电稳定平台会受到包括飞机自身姿态的变化，气流的冲击，电机的振动等扰动影响，使光电载荷的视轴发生震颤甚至是偏离既定目标，严重影响了获取任务目标的图像质量。因此，如何提高平台系统对扰动的抑制能力，是提高视轴稳定精度的关键所在，也是本文研究的重点。 本文分析了光电稳定平台的结构和组成，并对影响视轴稳定的扰动因素做了深入研究。针对经典控制方法受制于系统机械谐振的影响，提出将自抗扰控制方法与传统控制方法相结合，并将重复控制策略引入光电稳定平台的控制系统，以解决电机波动力矩对扰动观测值的影响。设计基于重复控制和自抗扰的光电稳定平台控制系统，取得了令人满意的视轴稳定精度。本文主要研究内容如下： 1．详细分析了两轴四框架稳定平台的结构和框架联接关系，给出了这种结构相比于两轴两框架平台结构的优点。并对框架间相互力矩传递关系以及转动惯量耦合关系做了详细阐述。分析了稳定平台中最重要的测量原件-陀螺传感器的工作原理和消除噪声方法。简要介绍了稳定平台控制系统的工作原理，为设计扰动隔离方法和控制系统提供了方向。 2．深入分析光电稳定平台控制系统中的关键部件的工作原理和数学模型，并利用电流环对每一个框架模型进行简化处理，保证了恒定的力矩输出。根据影响视轴稳定的扰动产生原因和作用机理，将扰动分为模型、力矩和电机的干扰等并给出各自的近似模型。并将这些扰动的作用总和看作一个等效电压的作用，简化了系统的模型，而且与自抗扰控制方法中的扰动分析方法相吻合。 3．在平台速度稳定回路中，利用传统控制方法中的平方滞后控制器和平方PI控制器，取得了不错的扰动隔离效果，但是受到系统机械谐振频率的限制，系统带宽无法做到更高，从而令系统视轴稳定精度很难进一步提高。本文在传统控制系统的基础上，将自抗扰控制器引入光电稳定平台控制系统之中，建立了自抗扰控制系统，完全绕开了机械谐振对控制系统性能提高的限制条件。并提出利用LuGre摩擦力模型对扰动观测值的“超调”现象进行实时修正，提高了扰动观测值的准确度，从而进一步提高了自抗扰控制器的扰动抑制能力。 4．观察扩张状态观测器的观测值，发现观测值的波形存在波动现象，详细分析这种现象产生的原因，引出电机的电磁波动力矩的影响，这种波动力矩使扰动观测值出现高频、小幅的跳变，使扰动观测值不能很好地跟踪系统受到的扰动，影响自抗扰控制系统的扰动抑制能力。提出基于“内膜原理”的重复控制策略，很好地抑制电机的电磁波动力矩对扰动观测值的影响。本文针对两轴四框架平台设计了改进型重复控制器，设计并优化了低通滤波器以及动态补偿器。 5．结合传统控制策略，设计了基于自抗扰控制器和重复控制器的光电稳定平台控制系统。在摇摆台上进行速度稳定实验和目标跟踪实验，测试控制系统对1°，3Hz内扰动的抑制效果。实验结果表明，相比与传统的控制方法，本文设计的稳定控制系统，随着扰动频率的变化，扰动隔离度提高范围为（6.28-16.9）dB。在跟踪18°，0.03Hz的正弦运动目标时，采用本文控制系统时，视轴以21°的幅度跟踪目标，偏差只有1/6，比采用传统方法的跟踪性能提高了75%，而且稳态速度残差也比传统方法明显减小，实验也表明控制系统具有很强的鲁棒性。因此，基于自抗扰控制策略和重复控制策略的光电稳定平台控制系统，对提高航空光电稳定平台控制系统的视轴稳定精度具有很高的实用价值。 |
| 英文摘要 | High precision airborne photoelectric stabilized platform is mounted on the aircraft pods of photoelectric detection equipment, which has the mechanical structure of the precision and accurate computer control system. Currently it widely used in the field of national defense military for the capture of the air or ground military targets, tracking, and target tasks.However, the optical axis of photoelectric platform may shake even deviate from the goal because of external environment of various disturbances in the process of flight , which seriously affect the image quality of mission objectives.Therefore, how to improve the disturbance rejection capability of the photoelectric platform system is key to improving the accuracy of LOS stabilization and the focus of this study. This paper analyzes the structure and composition of the photoelectric stabilized platform,and then does an in-depth study of the disturbance factors which affecting LOS stabilization.By analyzing the causes and characteristics of electromagnetic torque disturbance in the process of Dc torque motor running ,repetitive control strategy is introducted to the photoelectric stabilized platform control system, in order to solve the interference of electromagnetic torque disturbance.Combined with repetitive control strategy and the immunity control strategy, giving full play to the advantages of each control strategy, the photoelectric stabilized platform control system were designed and obtained the satisfactory visual axis stability precision.This article main research content is as follows: 1. First analyzes in detail the two axis four frame structure of the stabilized platform and frame connection relationship.Compared to the two axis framework platform structure, the advantages of this structure is explained .And the torque transfer relationship between the frame and shaft coupling relationship is explained in detail. Then analyzes the principle and the method to eliminate noise of the gyro sensor ,which is the most important measuring device in the stabilized platform .This paper briefly introduces the working principle of the control system of stabilized platform, this paper provides direction for improving the disturbance rejection capability and designing control system. 2. By analyzing the working principle and mathematical model of the key component in the photoelectric stabilized platform ,we simplify every frame model using current loop for constant torque output. According to the cause and the mechanism which effecting axis stabilization, the disturbances are devided into models, torque and motor disturbances and so on. The sum effect of these disturbances as an equivalent voltage function simplifies the system model and it also fits the perturbation analysis method in the auto-disturbance-rejection control method. 3. When platform run steady speed working state, the electromagnetic wave characterized by periodic disturbance torque, torque by using the traditional controller is difficult to do good inhibitory effect to this kind of periodic disturbance.Repetitive control strategy is developed on the basis of the principle of membrane control method, its characteristic is the system in theory can be done to external periodic reference signals astatic tracking, or completely suppress periodic disturbance.In this paper, the modified repetitive control system, according to two axis four frame platform related the repetitive controller parameters design of low pass filter and dynamic compensator, and its application in the stability control of airborne photoelectric stabilized platform system, well restrain the influence of electromagnetic torque fluctuations. 4. Traditional control methods have their limitations . Close analyzing the outcome based on extended state observer(ESO) , a fluctuation phenomena arises . It turns out that electromagnetic torque of the motor has a influence on tracking system , furthermore it has an impact on Auto-disturbance- rejection control system's work . The test in this article runs on the photoelectric stabilized platform control system . By using internal model control strategy the electromagnetic torque of the motor is suppressed. 5. Based on ADRC and repetitive controller and combined with traditional controller, photoelectric stabilized platform control system is designed. The speed stability test and target tracking experiment was carried out on the vibration.Compare the designed photoelectric stabilized platform control system with Square hysteresis of traditional control method,which do a research on the disturbance control ability within 1°,3Hz.The experimental results showed that, as the change of disturbance frequency, disturbance isolation degree increased(6.28-16.9)Db with the designed control system which compared with the traditional control method.And the designed control system has strong robustness ,which allows the control object parameters change in the range of 15%. Moreover, the designed control system shows superior performance in the reliability experiments such as: high-low-temperature, vibration impact,et..Therefore, the designed photoelectric stabilized platform control system has high practical value in improving visual axis stability precision with Aerial photoelectric stabilized platform control system. |
| 公开日期 | 2015-12-24 |
| 内容类型 | 学位论文 |
| 源URL | [http://ir.ciomp.ac.cn/handle/181722/48918]  |
| 专题 | 长春光学精密机械与物理研究所_中科院长春光机所知识产出 |
| 推荐引用方式 GB/T 7714 | 魏伟. 高精度机载光电平台视轴稳定技术研究[D]. 中国科学院大学. 2015. |
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