Fuzzy Variable Structure Control of dynamical systems with an application to micro satellite stabilization

Abstract

This paper is on determining a hybrid form of control which has both Fuzzy Logic Control (FLC) and Variable Structure Control (VSC) integrated. This proposed Fuzzy Variable Structure Control (FVSC) approach combines the power of approximate reasoning of FLC with the switching synthesis used in VSC. The FVSC is applied to control and stabilize a micro satellite in space. A model of satellite is used in this study in order to ensure the applications of FVSC in space. The simulation results indicate that the fuzzy logic can be advantageously used to minimize the chattering and improve the time response in the satellite system. MATLAB SIMULINK is extensively employed in this work.

Performance evaluation of a fuzzy variable structure satellite attitude controller under sensor data delay

“…For example, the unit of the actuator gains can be Nm/V for an analogue actuator, as it is in this application, and can be just a binary numeric value, such as 1 least significant bit digit change per mNm for a digital type of actuator. Table 2, respectively [23,24,26]. The membership functions are selected as triangles.…”

“…The sliding line provides robustness to the controller by changing the structure of the controller, hence the name 'variable structure controller'. The design of the FVSC is established according to [23,24,26,[31][32][33][34][35]. First, a suitable switching function, S, is selected.…”

“…The switching function output (S) determines the sign of the final output of the FC. The FC output is scaled by switch gain blocks and then switched according to the actual value of the S. FC adds further robustness to the controller [23,24,26]. The parameter 'rate gyro gain' sets a gain factor for the angular velocity sensor.…”

“…Actuator gains 0.01 Nm/V FC uses the angular position error as input. The input and output membership functions and rule base of the FC are presented in Figures 4 and 5, and Table 2, respectively [23,24,26]. The membership functions are selected as triangles.…”

“…There are very few studies that combine FC and VSC, The fuzzy VSC (FVSC) concept was investigated through a very simple satellite model without any delay in the system in [23,24]. Dong et al proposed a method in which the attitude stabilization of a networked flexible spacecraft during a large angle slew maneuver was achieved by a novel type of adaptive fuzzy sliding mode control (SMC) [25].…”