Appl. Sci. 2022, 12, 5273. https://doi.org/10.3390/app12105273 www.mdpi.com/journal/applsci
Article
Variable Structure PID Controller for Satellite Attitude Control
Considering Actuator Failure
Yong Qi
1,2,
*, Haizhao Jing
2
and Xiwei Wu
3
1
School of Electronic Information and Artificial Intelligence, Shaanxi University of Science and Technology,
Xi’an 710021, China
2
Shaanxi Joint Laboratory of Artificial Intelligence, Shaanxi University of Science and Technology,
Xi’an 710021, China; 201915030414@sust.edu.cn
3
School of Automation, Northwestern Polytechnical University, Xi’an 710129, China;
wxw-treffen@mail.nwpu.edu.cn
* Correspondence: author: qiyong_sust@163.com
Abstract: In this paper, a variable structure PID controller with a good convergence rate and ro-
bustness for satellite attitude is proposed. In order to improve the system convergence rate, the
variable structure for the proportional and differential term was designed, and an angular velocity
curve with a better convergence rate was achieved by this variable structure. In addition, an inte-
gral partitioning algorithm was designed, and the system robustness to disturbance torque was
improved; meanwhile, the negative effect of the integral term was avoided during the converging
process. The actuator failure condition was also considered, and a fault tolerant control algorithm
was designed. System stability was analyzed by the Lyapunov method, and its performance was
demonstrated by numerical simulation.
Keywords: satellite attitude control; PID control; fault tolerant; actuator failure
1. Introduction
With the rapid development of the aerospace industry, more and more attention has
been paid to the high precision attitude control for satellites. To ensure high precision,
high reliability, and a fast convergence rate of the satellite, the control system of the sat-
ellite must have sufficient control capability. At present, many researchers have studied
the basic theories and problems of satellite attitude control [1–6]. As a commonly used
method in satellite attitude control, PID control can achieve the closed-loop control sys-
tem, reaching a steady state, and it has the advantages of a simple structure and easy
engineering implementation. However, the control accuracy of PID control is relatively
low, which often cannot meet the requirements of current missions. Furthermore, in or-
der to ensure the stability of the satellite attitude control system under actuator failure
(which is quite often in space missions and is one of the major reasons for mission fail-
ures), it is necessary to enhance the system fault tolerant capability to actuator failures.
Hence, it is necessary to modify current PID controllers to meet the precision, reliability,
and fast convergence rate requirements.
For the PID control method, Zhang [7] designed a low-complexity structured
H-infinity controller for flexible satellite attitude control considering interference sup-
pression. Zhang [8] designed an adaptive sliding mode integral controller for the control
of the robotic arm of the spacecraft and used a PID-type integral sliding mode control
surface to reduce the steady-state error. Li [9] designed a fuzzy PID control algorithm
according to the characteristics of the three-axis stable zero-momentum wheel. The au-
thors used a PID control algorithm to manipulate the satellite attitude, but the result
could not achieve the desired control accuracy. In summary, researchers made some
Citation: Qi, Y.; Jing, H.; Wu, X.
Variable Structure PID Controller for
Satellite Attitude Control
Considering Actuator Failure. Appl.
Sci. 2022, 12, 5273. https://doi.org/
10.3390/app12105273
Academic Editors: Yuqing Li,
Yuehua Cheng, Qingxian Jia and
Guang Jin
Received: 6 April 2022
Accepted: 18 May 2022
Published: 23 May 2022
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