A nonlinear control law design based upon the backstepping approach is addressed for attitude maneuver control of spacecraft by momentum transfer (MT) in the presence of disturbance. For MT, a traditional method usually applies constant torque as an input, which tends to produce significant residual oscillation. Enhanced methods such as optimal control can somewhat reduce the residual oscillation, but may not be enough for minimum residual motion. Feedback linearization technique can drive the final nutation angle small enough, but it is rather sensitive to parameter uncertainty. The proposed method here takes advantage of nonlinear control approach with small steady-state nutation angle. Sensitivity about parameter uncertainties by feedback linearization can be reduced by the backstepping technique. Stability of the resulting control law is guaranteed by the Lyapunov stability theory. Boundedness of the control law is presented to validate practical merit of the proposed control law.

Many conventional flight control designs assume the aircraft dynamics to be linear about some nominal flight condition. But this paper deals with the problem of controlling an aircraft explicitly considering its nonlinear dynamics. Our main tool will be backstepping [4], a Lyapunov based design method that has received a lot of attention in the recent years. Compared to other nonlinear techniques like feedback linearization, backstepping offers a more flexible way of dealing the nonlinearities. Using Lyapunov functions, their influence on the system can be analyzed and stabilized, and thus in a sense, useful nonlinearities can be cancelled or dominated by the control signal. Not having to cancel all nonlinearities means that the resulting control law may be much simpler than if feedback linearization had been used. In this paper, the application is angle of attack and sideslip control. Using inherent characteristics, we will show that despite its nonlinear dynamics the required state of the R-UAV is stabilized around the desired trajectory, regardless of the initial condition. The remainder of the paper is organized as follows- In Section 2, a nonlinear model of the Rotary wing Unmanned Aerial Vehicle (R-UAV) is described and the dynamic equations are transformed into pure-feedback form which is crucial to the backstepping design. In Section 3, the backstepping control law is derived in detail, and in Section 4 the control law is implemented using a generic simulation model of R-UAV.

A robust controller design methodology for high speed reentry vehicles (HSRV) is presented in this paper. The design methodology is based on a nonlinear backstepping technique. High speed reentry vehicles often contain signiflcant nonlinearities in the dynamics equation of motion which are partially caused by the high velocities and ∞ight path trajectories. These two factors tend to produce signiflcant aerodynamic forces and moments on the vehicle. The nonlinear backstepping control technique provides an alternative to methods such as piecewise linearization-based gain scheduling and feedback linearization. Backstepping approaches utilize Lyapunov theory to guarantee stability of the closed system and the methods are inherently recursive. Nonlinear optimization is also used to guarantee the accuracy of the mapping between the actuators and applied moments and an adaptive term is included to compensate for the moment bias. The proposed design procedure turns out to be simpler than designs based on alternative methods and the design appears relatively easy to implement.

自动驾驶仪设计的传统方法是基于分段线性化的增益规划法.近年来,以反馈线性化为基础的各种非线性控制技术得到了广泛的研究.文章基于一种不同于反馈线性化的退步控制思想,提出了一种新的非线性反馈自动驾驶仪设计方法.该方法考虑了系统输入的不确定性,采用了非线性在线优化方法保证舵偏与力矩之间更精确的映射,同时,通过引入自适应项以修正各种力矩偏差.利用这种方法,为再入飞行器设计了自动驾驶仪.仿真结果表明,提出的自适应退步控制方法是有效的,且设计过程简单,易于实现.

针对高速再入飞行器模型的快时变 ,强耦合 ,严重非线性的特点 ,采用反馈线性化方法 ,设计了自动驾驶仪 ;同时采用最优制导律设计与理想速度曲线相结合的方法 ,设计了能同时保证末端制导精度及速度方向、大小的制导律。最后 ,进行了六自由度仿真 ,结果表明 :设计的制导律及控制方案是合理、有效的 ,易于实现。

提出了一种基于RBF网络扰动力矩补偿的控制技术.通过在传统PID控制的基础上,引入RBF网络补偿环节,进一步抑制了扰动力矩的影响,提高了卫星姿态控制精度.首先给出了RBF网络的学习算法,然后根据全补偿原则设计了神经网络补偿姿态控制方案,最后结合某型卫星的姿态控制系统设计实例,进行了数学仿真.结果表明:有RBF网络补偿的系统,姿态的稳态精度得到了明显的改善.

In this paper, a new kind of control strategy for design of autopilot with nonlinear feedback based on backstepping technique was presented. Also the autopilot of reentry aerocraft was designed with this nethod. The simulation results show that the method of backstepping proposed in this paper is efficient. The design process is simplex than others and easy for implement.

针对高速再入飞行器模型的快时变、强耦合及严重非线性的特点,采用变结构控制方法设计了自动驾驶仪;同时,采用最优化设计理论与理想速度曲线相结合的方法,设计了能同时保证末端制导精度及速度方向、大小的制导律.最后,进行了系统六自由度仿真,结果表明:本文设计的制导律及控制方案合理、有效,易于实现.

This paper presents a control scheme based on NN disturbance compensation for attitude control of satellite. At first, we present an improved algorithm of RBF NN from the general algorithm, regulation orthogonal least square (ROLS). Then, base on the problem of attitude control of a satellite under development, we design a NN compensation controller for high accuracy orientation phase. The simulation results show that the improved algorithm is efficient and the NN compensation scheme is feasible.