Application Research of Network Learning Algorithm Based on Neural Network Disturbance Compensation in Satellite Attitude Control

Based on the satellite attitude control method, this paper proposes an attitude control method based on neural network disturbance compensation. The paper firstly analyzes the neural network algorithm and proposes an orthogonal least squares algorithm to implement network learning. In this paper, a set of high-precision directional neural network compensation controllers is designed for the attitude control of acupuncture small satellites. The feasibility of the improved orthogonal least-squared algorithm combined with the neural network supplementary control method in satellite attitude control is verified by experiments.

Simulink-based simulation platform design and faults impact analysis of attitude control systems

The satellite attitude control system (SACS) is a complicated system. In order to reflect the relationship among different components in SACS and analyse the impact of component faults on system performance, a complete simulation platform of the SACS based on Simulink is built in this paper. With the embedding of the specific reaction flywheel, gyroscope and earth sensor model, and the design of the controller based on the quaternion feedback, the simulation platform can not only simulate the real SACS at the component level, but it can also realise the injection of component faults for analysing the system performance. Simulations are conducted to verify the performance of the simulation platform. Simulation results show that this simulation platform has the ability to accurately reflect the control performance of the SACS, and the output accuracy of the component model is high. The research results reveal that this simulation platform can provide model support for verifying the algorithm of fault diagnosis, prediction and tolerant control of the SACS. This simulation platform is easy to use and can be expanded and improved.

Satellite attitude control using environmental forces based on variable structure control

The present thesis examines the use of environmental forces for satellite attitude control using variable structure control. The system comprises of a satellite with control flaps to utilize environmental forces such as solar radiation pressure and aerodynamic forces. A variable structure control approach has been adopted to develop control law for suitably rotating the control flaps to achieve desired satellite attitude performance. The detailed numerical simulation of the governing nonlinear system equation of motion including the effects of various system parameters on the controller performance establishes the effectiveness of the proposed control strategy. The numerical simulation matches with the analytical results. Furthermore from analysis, the proposed controller is found to be robust against parameter uncertainties and external disturbances and its performance is superior in comparison to other strategies proposed in the literature. Thus, the robustness of the proposed control strategy and utilizing natural environmental forces for attitude control makes the proposed concept attractive for future space applications.

Satellite attitude control using environmental forces based on variable structure control

The present thesis examines the use of environmental forces for satellite attitude control using variable structure control. The system comprises of a satellite with control flaps to utilize environmental forces such as solar radiation pressure and aerodynamic forces. A variable structure control approach has been adopted to develop control law for suitably rotating the control flaps to achieve desired satellite attitude performance. The detailed numerical simulation of the governing nonlinear system equation of motion including the effects of various system parameters on the controller performance establishes the effectiveness of the proposed control strategy. The numerical simulation matches with the analytical results. Furthermore from analysis, the proposed controller is found to be robust against parameter uncertainties and external disturbances and its performance is superior in comparison to other strategies proposed in the literature. Thus, the robustness of the proposed control strategy and utilizing natural environmental forces for attitude control makes the proposed concept attractive for future space applications.

Fluid Dynamic Actuators For Satellite Attitude Control

In this thesis, the application of fluid based actuators for satellite attitude control and thermal management is investigated. The actuator named Pumped Fluid Loop Actuator (PFLA) is examined to satisfy the need for integrated attitude and thermal management systems while considering strict mass and power budgets. A nonlinear voltage-driven control law is formulated and the feasibility of the PFLA for satellite attitude maneuvers is addressed. A high-fidelity PFLA model is developed. The power consumption of the PFLA is examined in the presence of sensor noise. Simulation results demonstrate its feasibility for attitude tracking capabilities of up to ± 0.01° with slew rates of up to 10 °/s. Next, the limitations of existing fluid dynamic actuators are overcome through the design of a novel Patent Pending Pumped Fluid Spherical Actuator (PFSA). The PFSA extends the capabilities of fluid dynamic actuators and allows for satellite attitude control about any arbitrary axis through spherical design, and introduces a fault-tolerant functionality that allows it to be used as a sensor in the event of rate-gyro failure of the attitude determination subsystem. The dynamic model of the PFSA is obtained through computational fluid-dynamics and finite-element analysis using the grid-independent solution. The passive stabilization capabilities of the PFSA are investigated. Simulation results show an order of three-fold reduction in settling time in comparison to existing fluid dynamic actuators. Lastly, a design modification is proposed for PFLA in order to examine its thermal management capabilities. A comprehensive investigation is carried out to perform thermal transport from onboard electronics through conduction and convection. Simulation results demonstrate the advantages of thermal transport while considering fluid rotation inside the PFLA as opposed to stationary fluid.

Fluid Dynamic Actuators For Satellite Attitude Control

In this thesis, the application of fluid based actuators for satellite attitude control and thermal management is investigated. The actuator named Pumped Fluid Loop Actuator (PFLA) is examined to satisfy the need for integrated attitude and thermal management systems while considering strict mass and power budgets. A nonlinear voltage-driven control law is formulated and the feasibility of the PFLA for satellite attitude maneuvers is addressed. A high-fidelity PFLA model is developed. The power consumption of the PFLA is examined in the presence of sensor noise. Simulation results demonstrate its feasibility for attitude tracking capabilities of up to ± 0.01° with slew rates of up to 10 °/s. Next, the limitations of existing fluid dynamic actuators are overcome through the design of a novel Patent Pending Pumped Fluid Spherical Actuator (PFSA). The PFSA extends the capabilities of fluid dynamic actuators and allows for satellite attitude control about any arbitrary axis through spherical design, and introduces a fault-tolerant functionality that allows it to be used as a sensor in the event of rate-gyro failure of the attitude determination subsystem. The dynamic model of the PFSA is obtained through computational fluid-dynamics and finite-element analysis using the grid-independent solution. The passive stabilization capabilities of the PFSA are investigated. Simulation results show an order of three-fold reduction in settling time in comparison to existing fluid dynamic actuators. Lastly, a design modification is proposed for PFLA in order to examine its thermal management capabilities. A comprehensive investigation is carried out to perform thermal transport from onboard electronics through conduction and convection. Simulation results demonstrate the advantages of thermal transport while considering fluid rotation inside the PFLA as opposed to stationary fluid.