In this study, the authors propose a unified approach to saturated proportional derivative (SPD) controller design for asymptotic attitude stabilisation of spacecraft subject to actuator constraints. It is shown that a class of simple and high computation efficient SPD controller can ensure asymptotic stabilisation of spacecraft with actuator constraints. The proposed SPD controller utilises the general saturation function, and thus provides a unified framework for asymptotic stable control design of spacecraft subject to actuator constraints. Advantages of the proposed design framework include the intuitive structure, high computation efficiency, easy implementation and asymptotic stabilisation with the ability to ensure that actuator constraints are not violated. This is accomplished by selecting control gains a priori. Two examples are presented to demonstrate the effectiveness and the improved performance of the proposed approach.
IntroductionStabilisation of spacecraft is quickly developing in the last few decades and much progress has been achieved. Several control schemes that stabilise the attitude of spacecraft can be found in the literature. Specifically, in [1], passivity between the angular velocity vector and the Euler parameter vector of a spacecraft is established and an adaptive control is proposed. Some interesting passivity velocity-free controllers are developed in [2]. Tsiotras [3] extend this passivity result. For progress on attitude stabilisation of spacecraft by using the unit-quaternion and angular velocity in the feedback control law, see [4][5][6][7] and the references within. In [8][9][10][11], various optimal attitude stabilisation control schemes have been proposed. The effort that stabilises the spacecraft with disturbance can be found in [12][13][14], and the references within. Recently, some interesting finite-time stable controllers for attitude stabilisation of spacecraft have been proposed [15][16][17]. Fault-tolerant stabilisation result of spacecraft can be found in [18,19]. A minor drawback that remains for these controls is the spacecraft actuators are assumed to be able to provide any requested torque. This assumption can lead to difficulties in practice since the torque amplitude is limited in actual spacecraft. It is known that control system design approaches that do not incorporate input constraints directly into the design may result in degraded or unpredictable motion and thermal or mechanical failure, if the controller commands more torque than the actuators can supply from the control [20][21][22].Taking into account actuator constraints, several effective schemes have been proposed for attitude stabilisation of spacecraft. In particular, Tsiotras and Luo [23] construct a saturation control law for an underactuated spacecraft, by using a non-standard attitude representation and decomposing the general motion into two rotations. Boskovic et al. [24] develop two robust saturated sliding mode controllers for asymptotic stabilisation of uncertain spacecraft. Wallsgrove...