航天器精确节能模糊脉冲调宽控制器的设计

为实现航天器精确、节能的姿态或轨道控制,提出一种采用脉冲宽度调制PWM(Pulse Width Modulation)与模糊比例微分PD(Proportional Differential)控制相结合的模糊PD-PWM控制器.其中PWM能将开关型控制转化为相应的精确线性控制,而模糊PD控制在能量消耗限制不同情况下可实现两种快速、节能的控制过程.在分析大气层外拦截器EKV(Extra-atmospheric Kill Vehicle)处于目标捕获和末制导阶段对姿控系统的不同性能要求的基础上,以EKV姿控系统为例介绍了模糊PD-PWM控制器的设计和优化过程.说明了模糊PD控制器隶属度函数的设计、待优化参数的选择以及模糊控制规则的设计,重点叙述了遗传算法GA(Genetic Algorithms)中适应度函数的设计方法,并对隶属度函数进行了优化.仿真结果证明优化后的控制器能满足EKV不同阶段姿态控制要求,具有精确、节能的特点. 

Design of fuzzy pulse width modulation controller with accuracy and energy retrenchment applied to spacecraft

The fuzzy proportional differential(PD) pulse width modulation(PWM) controller which adopts PWM and fuzzy PD control was introduced into accurate and energy-retrenched control for attitude and orbit of spacecraft.PWM can convert on-off type control to relevant accurate linear control,and fuzzy PD control can implement two speedy and energy retrenched control processes with different consumed energy restricts.The performance demands on attitude control system were analyzed in target-capture and terminal-guidance phases of extra-atmospheric kill vehicle(EKV).Fuzzy PD-PWM controllers were designed and optimized to achieve the demands.The design of membership functions and fuzzy control rules,and the selection on parameters for optimization were discussed for those controllers.Genetic algorithms(GA) were used to optimize the membership functions of input fuzzy variables for expected demands.And the fitness function design for GA was explained.The simulations prove that the optimized controllers can respectively satisfy the demands on attitude control for EKV in different phases with accuracy and energy retrenchment.