Cooperative Control For Spacecraft Formation With Constrained Communication Resources

With the rapid development of aerospace industry and space technology,single satellite has not possessed the ability to realize the increasingly complex spacecraft missions.Since the small satellite formation has a few virtues such as low cost,high reliability,and distinguished flexibility,it has become a new type of space technology which leads the future aerospace development trend.It is worth pointed out that,due to physical weight constraints small satellites can only carry communication equipments with limited performance.Moreover,the distances between the small satellites are always large during performing missions,thus there exists some unexpected phenomenon such as insufficient bandwidths.This dissertation will make a systemic investigation on attitude cooperative control and integrated orbit and attitude control for small satellite formation with constrained communication resources.For the relative position and velocity estimation problem of small satellite formation,considering the non-Gaussian measurement noises and space disturbance force,this dissertation proposes an extended sliding mode observer method to estimate the relative orbit position and velocity.Compared to the traditional Kalman filter method,our developed autonomous navigation approach don’t need to make linearization on the relative dynamic equation,which thus maintains the model precision.Also,the designed method can cope with non-Gaussian measurement noises,and obtain reconstruction on the space disturbance moment vector.For the attitude cooperative control issue of small satellite formation with limited communication information,to economize the communication bandwidth and computation sources among the satellites,considering unknown external disturbance and actuator faults,this dissertation develops an event-triggered based attitude cooperative fault tolerant control scheme.The proposed control law can compensate the effects of external disturbance,actuator faults and the state errors resulted from the event-triggered communication,and at the same time ensure the asymptotic stability of the attitude cooperative control systems.For the attitude cooperative control problem with communication transmission delay,this thesis employs the Encoder-Decoder transmission scheme(quantization)for the satellite formation to decrease the communication data rate and save the bandwidths.Based on the quantized information,a terminal sliding mode attitude cooperative control scheme and an exponent-logarithmic terminal sliding mode attitude cooperative control strategy are designed,respectively,both of which can guarantee the spacecraft formation attitude cooperative control systems to achieve the desirable objectives in finite time.Moreover,to avoid the chattering phenomenon of the sliding mode controller,based on the backstepping control theory and Chebyshev Neural Networks,a new attitude cooperative controller is developed to improve the precision of the formation spacecraft attitude cooperative control.For the integrated orbit and attitude control for spacecraft formation with limited communication channel,the coupled dynamics of relative position and attitude are described with the Lie group S E(3)method.Based on the model,an integrated orbit and attitude control strategy based on event-triggered and quantized signals is presented,which ensures the convergence and stability of the orbit-attitude coupled closed-loop control systems with the compensations of the state errors caused by the event-triggered mechanism and signal quantization.