基于摩擦力补偿的干扰观测器在航空光电稳定平台的应用

发布时间：2019-01-10 06:51

【摘要】：航空光电稳定平台广泛应用于侦察和目标定位等领域,有隔离载体扰动,保持视轴指向稳定的功能。视轴稳定精度越高,平台对目标信息的获取越准确。在平台受到的众多扰动因素中,轴系间摩擦力矩对视轴稳定精度的影响尤其明显。针对这一问题,文中将摩擦补偿与干扰观测器相结合的控制策略应用到平台控制系统中。本文研究的主要内容有以下几点:(1)建立平台速度环的模型,为后续扰动抑制策略的设计奠定基础。根据直流力矩电机的动力学方程和电机与负载之间的关系建立系统的被控模型。并结合系统中的扰动,通过“等效电压”的方式建立含有扰动的系统模型。(2)采用LuGre模型对平台中的摩擦力矩建模。并通过两步参数辨识法对平台的摩擦参数进行辨识。第一步,通过实验得到平台的Stribeck曲线,利用数据拟合的方法得到LuGre模型的静态参数;第二步,通过对低速时摩擦模型的简化,得到LuGre模型动态参数值的范围,然后采用遗传算法得到动态参数的值。在参数辨识的基础上得到平台摩擦补偿模型,并通过实验验证模型的有效性。(3)在摩擦补偿的基础上,针对残余干扰设计干扰观测器。首先,详细介绍了干扰观测器设计的步骤,然后,将改进后的干扰观测器和摩擦补偿相结合。并设计仿真实验对该控制方案进行验证。(4)将摩擦补偿和干扰观测器相结合的控制方案应用到光电稳定平台中进行实验验证。经验证,采用该控制方案后,系统由于摩擦引起的低速爬行现象明显减弱。将平台安装在飞行模拟器上,测试该控制方案对频率为3.0Hz以内扰动的抑制能力。实验结果表明:采用该控制方案后平,平台速度环对扰动的隔离程度至少提高了14.52d B,最优情况已经达到20.98d B。而且该控制方案具有很强的鲁棒性,允许被控对象的参数值在±10%的范围内浮动,具有较高的应用价值。
[Abstract]:The aeronautical photoelectric stabilization platform is widely used in reconnaissance and target positioning. It has the function of isolating carrier disturbance and maintaining the stability of the axis of view. The higher the accuracy of visual axis stabilization, the more accurate the platform is to obtain target information. Among the many disturbance factors on the platform, the friction moment between shafting has an obvious effect on the stability accuracy of the visual axis. To solve this problem, the control strategy combining friction compensation and disturbance observer is applied to the platform control system. The main contents of this paper are as follows: (1) the model of the platform velocity loop is established, which lays the foundation for the design of the subsequent disturbance suppression strategy. According to the dynamic equation of DC torque motor and the relation between motor and load, the controlled model of the system is established. Combined with the disturbance in the system, the system model with disturbance is established by "equivalent voltage". (2) LuGre model is used to model the friction moment in the platform. The friction parameters of the platform are identified by two-step parameter identification method. In the first step, the Stribeck curve of the platform is obtained by experiments, and the static parameters of the LuGre model are obtained by the method of data fitting. In the second step, the range of dynamic parameters of LuGre model is obtained by simplifying the friction model at low speed, and then the value of dynamic parameter is obtained by genetic algorithm. The friction compensation model of platform is obtained on the basis of parameter identification, and the validity of the model is verified by experiments. (3) on the basis of friction compensation, disturbance observer is designed for residual disturbance. Firstly, the design steps of disturbance observer are introduced in detail. Then, the improved disturbance observer is combined with friction compensation. Simulation experiments are designed to verify the control scheme. (4) the friction compensation and disturbance observer are applied to the optoelectronic stabilization platform for experimental verification. It is proved that the low speed crawling phenomenon caused by friction is obviously weakened after adopting this control scheme. The platform is installed on the flight simulator to test the ability of the control scheme to suppress the disturbance within the frequency of 3.0Hz. The experimental results show that the disturbance isolation degree of the velocity loop of the platform is increased at least 14.52 dB, and the optimal condition has reached 20.98 dB. Moreover, the control scheme has strong robustness and allows the parameters of the controlled object to float in the range of 卤10%, so it has high application value.
【学位授予单位】：中国科学院长春光学精密机械与物理研究所
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：V243

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