基于四元数的永磁动量球位置/电流双闭环控制

Position and Current Double Closed Loop Control of Reaction Sphere Actuator Based on Quaternion

永磁动量球运动范围大,采用欧拉角描述其姿态时,容易产生奇点。该文采用四元数作为姿态描述量,结合刚体转动动力学方程,得到了永磁动量球动力学模型;利用球谐函数便于进行旋转变换的优点,采用球谐函数来描述永磁动量球的电磁转矩模型。永磁动量球在运行过程中,环境温度会逐渐升高,电磁参数会产生变化,为了保证其较好的动态性能,该文采用位置/电流双闭环的控制方法,即位置环采用线性自抗扰控制,实现扰动动态补偿,提高永磁动量球的快速性和动态响应能力;电流环采用比例积分控制,实现电流稳定跟踪电流给定,提高永磁动量球的快速性和动态响应能力。仿真结果表明基于电流/位置双闭环控制比单独自抗扰控制方法具有更好的跟随性能。

The motion range of reaction sphere actuator is large.When the Euler angle is used to describe its posture,it is easy to produce singularities.In this paper,the quaternion is used as the attitude description and the dynamic equation of the rigid body rotation is combined to obtain the dynamic model of the reaction sphere actuator.The spherical harmonic function is used to describe the electromagnetic torque model of the reaction sphere actuator.During the operation of the reaction sphere actuator,the temperature of the environment will increase gradually and the electromagnetic parameters will change.In order to ensure its better dynamic performance,the position/current double closed loop control method is adopted in this paper.The linear self disturbance rejection control is adopted in the position loop to realize the dynamic compensation of the disturbance and improve the rapidity and dynamic response capability of the permanent magnet momentum exchange ball.The current loop adopts proportional integral control is adopted to ensure its accurate tracking of the target trajectory.The simulation results show that the current/position double loop control has better tracking performance than the single alone disturbance rejection control method.