Adaptive Backstepping Terminal Sliding Mode Attitude stabilization control for Moving Mass Rocket-propelled CubeSat

Author(s):  
Qian Pengjun ◽  
Lu Zhengliang
2018 ◽  
Vol 25 (5) ◽  
pp. 1008-1018 ◽  
Author(s):  
Ruidong Yan ◽  
Zhong Wu

There exist complex disturbances in the attitude control system of flexible spacecrafts, such as space environmental disturbances, flexible vibrations, inertia uncertainties, payload motions, etc. To suppress the effects of these disturbances on the performance of attitude stabilization, a super-twisting disturbance observer (STDO)-based nonsingular terminal sliding mode controller (NTSMC) is proposed in this paper. First, STDO is designed for a second-order dynamical system constructed by applying the lumped disturbance and its integral as state variables, and applying the integral as virtual measurement. Since the virtual measurement is obtained by integrating the inverse attitude dynamics, STDO not only avoids the differential operation of angular velocity, but also fully utilizes the information of a nonlinear model. By combining STDO with NTSMC, a composite controller is designed to achieve high-accuracy spacecraft attitude stabilization. Since most of the disturbances are compensated for by a STDO-based feedforward compensator, only a small switching gain is required to deal with the residual disturbances and uncertainties. Thus, the chattering phenomenon of the controller can be alleviated to a great extent. Finally, numerical simulations for the comparison between STDO-based NTSMC and nonlinear disturbance observer-based NTSMC are carried out in the presence of complex disturbances to verify the effectiveness of the proposed approach.


2018 ◽  
Vol 10 (8) ◽  
pp. 168781401877863 ◽  
Author(s):  
Ran Jiao ◽  
Wusheng Chou ◽  
Rui Ding ◽  
Mingjie Dong

The control of quadrotor equipped with a robotic arm has received growing challenges. This article proposes a new adaptive control strategy of quadrotor equipped with a 2-degree-of-freedom robotic arm. To consider the positional variety of the center of gravity caused by the motion of the robotic arm, the kinematic and dynamic models are built. Based on the presented models, a backstepping and sliding mode controller with a terminal sliding mode manifold is first applied to cope with the condition in which the robotic arm is motionless relative to the quadrotor. As the evolvement of the backstepping and sliding mode controller, a novel adaptive backstepping and sliding mode controller is then designed for the vehicle with the robotic arm wavering. The robustness and effectiveness of the proposed control law are investigated through both simulations and flight tests. With the proposed control laws, several simulations are conducted in conditions of both a variable and a constant center of gravity, and the performance of hovering is tested with a variable center of gravity in an experiment. Overall results show that the proposed adaptive backstepping control could estimate and compensate the variable center of gravity which may seriously influence the stabilization of quadrotor flying in the air.


2020 ◽  
Vol 17 (3) ◽  
pp. 172988142092642
Author(s):  
Yaoyao Wang ◽  
Rui Zhang ◽  
Feng Ju ◽  
Jinbo Zhao ◽  
Bai Chen ◽  
...  

To effectively reduce the mass and simplify the structure of traditional aerial manipulators, we propose novel light cable-driven manipulator for the aerial robots in this article. The drive motors and corresponding reducers are removed from the joints to the base; meanwhile, force and motion are transmitted remotely through cables. Thanks to this design, the moving mass has been greatly reduced. In the meantime, the application of cable-driven technology also brings about extra difficulties for high-precise control of cable-driven manipulators. Hence, we design a nonsingular terminal sliding mode controller using time-delay estimation. The time-delay estimation is applied to obtain lumped system dynamics and found an attractive model-free scheme, while the nonsingular terminal sliding mode controller is utilized to enhance the control performance. Stability is analyzed based on Lyapunov theory. Finally, the designed light cable-driven manipulator and presented time-delay estimation-based nonsingular terminal sliding mode controller are analyzed. Corresponding results show that (1) our proposed cable-driven manipulator has high load to mass ratio of 0.8 if we only consider the moving mass and (2) our proposed time-delay estimation-based nonsingular terminal sliding mode is model-free and can provide higher accuracy than the widely used time-delay estimation-based proportional–derivative (PD) controller.


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