Dynamics of an autonomous spacecraft control system at initial transition to a tracking mode

The problems of autonomous digital control of the information satellites and space robots during their initial transition to a tracking mode, namely in the initial orientation modes, are considered. Autonomous angular guidance and modularly limited vector digital control using a vector of the modified Rodrigues parameters are applying to bring the spacecraft’s orientation from completely arbitrary to the required one. The developed methods, algorithms and simulation results for a mini-satellite in a sun-synchronous orbit are presented.

Analysis of ways to improve the efficiency of various purpose spacecraft control through the flight control unification and integration

The article considers the problem of analyzing the possibility of increasing the control efficiency of spacecrafts and orbital groupings operating in different orbits, having a different composition of the ground control loop technical means and, as a consequence, different technological control cycles. The main purpose of the study is to substantiate the possibility of increasing the efficiency of control of the constantly expanding orbital grouping of the State Corporation “Roscosmos” through the rational use of MCC software and hardware (active means) in terms of their unification, the use of common computing resources to ensure the functioning of MCCs by various purposes spacecrafts with the ability of their operational redistribution in the flight control process. Examples of the implementation of the above approaches in the currently being created product “Roscosmos basic MCC” are given. The results of the analysis of the possibilities of using the Roskosmos basic MCC in existing and prospective projects are presented.

Development of mobile aircraft control system model with additive technologies

The article describes the parameter evaluation of mobile spacecraft control systems and identifies their main advantages in comparison with stationary assets. The model and the mobile spacecraft control system mock-up using additive technologies were developed with existing methods for prototyping complex technical systems. This model performs experimental operations of the prototype of the mobile control system, accompanies the spacecraft in the area of its radio visibility, simulates the implementation of technological cycles of spacecraft control, evaluates the parameters of the target equipment, analyzes the characteristics of the antenna system and the layout, conducts experiments and eliminates abnormal situations. It also optimizes the spacecraft testing based on the use of artificial intelligence techniques.

Improving the efficiency of reinforcement learning for a spacecraft powered descent with Q-learning

Reinforcement learning entails many intuitive and useful approaches to solving various problems. Its main premise is to learn how to complete tasks by interacting with the environment and observing which actions are more optimal with respect to a reward signal. Methods from reinforcement learning have long been applied in aerospace and have more recently seen renewed interest in space applications. Problems in spacecraft control can benefit from the use of intelligent techniques when faced with significant uncertainties—as is common for space environments. Solving these control problems using reinforcement learning remains a challenge partly due to long training times and sensitivity in performance to hyperparameters which require careful tuning. In this work we seek to address both issues for a sample spacecraft control problem. To reduce training times compared to other approaches, we simplify the problem by discretising the action space and use a data-efficient algorithm to train the agent. Furthermore, we employ an automated approach to hyperparameter selection which optimises for a specified performance metric. Our approach is tested on a 3-DOF powered descent problem with uncertainties in the initial conditions. We run experiments with two different problem formulations—using a ‘shaped’ state representation to guide the agent and also a ‘raw’ state representation with unprocessed values of position, velocity and mass. The results show that an agent can learn a near-optimal policy efficiently by appropriately defining the action-space and state-space. Using the raw state representation led to ‘reward-hacking’ and poor performance, which highlights the importance of the problem and state-space formulation in successfully training reinforcement learning agents. In addition, we show that the optimal hyperparameters can vary significantly based on the choice of loss function. Using two sets of hyperparameters optimised for different loss functions, we demonstrate that in both cases the agent can find near-optimal policies with comparable performance to previously applied methods.

Construction of ground control points for spacecraft using optimization-simulation model

The article deals with the application of simulation modeling and optimization-simulation approach to solving problems of synthesis of structures of automated spacecraft control systems, namely, the choice of spacecraft control points, which are multifunctional aggregates of stationary and mobile elements dispersed in space with developed technical means of receiving, transmitting and processing information. Various approaches to the joint use of optimization and simulation models in the synthesis of the structure of complex systems are analyzed. The main attention is paid to the possibility of joint use in the synthesis of optimization and simulation models, their rational interaction in optimization and simulation procedures that describe both the composition and interrelationships of the structural elements of the system, as well as dynamic and stochastic aspects of their functioning. An optimization-simulation approach based on the joint use of optimization and simulation models in the process of searching for optimal structure options is proposed. Rational mapping of a set of interrelated functions performed by a control system into a set of interconnected nodes with appropriate technical means, taking into account the costs of creating or reconstructing the system, the costs of operation and operation, the requirements of operational efficiency of management, the reliability of technical means, the survivability and globality of the control system and other characteristics. Consideration of the problem of optimizing the distribution of tasks included in the control loop by levels and control nodes of the system and determining a set of technical means that minimize the costs of equipping nodes with technical means and their operation when performing restrictions on efficiency, hardware reliability of performing control tasks, weight and energy consumption of on-board equipment, loading of nodes, etc.

Construction of ground control points for spacecraft using optimization-simulation model

The article deals with the application of simulation modeling and optimization-simulation approach to solving problems of synthesis of structures of automated spacecraft control systems, namely, the choice of spacecraft control points, which are multifunctional aggregates of stationary and mobile elements dispersed in space with developed technical means of receiving, transmitting and processing information. Various approaches to the joint use of optimization and simulation models in the synthesis of the structure of complex systems are analyzed. The main attention is paid to the possibility of joint use in the synthesis of optimization and simulation models, their rational interaction in optimization and simulation procedures that describe both the composition and interrelationships of the structural elements of the system, as well as dynamic and stochastic aspects of their functioning. An optimization-simulation approach based on the joint use of optimization and simulation models in the process of searching for optimal structure options is proposed. Rational mapping of a set of interrelated functions performed by a control system into a set of interconnected nodes with appropriate technical means, taking into account the costs of creating or reconstructing the system, the costs of operation and operation, the requirements of operational efficiency of management, the reliability of technical means, the survivability and globality of the control system and other characteristics. Consideration of the problem of optimizing the distribution of tasks included in the control loop by levels and control nodes of the system and determining a set of technical means that minimize the costs of equipping nodes with technical means and their operation when performing restrictions on efficiency, hardware reliability of performing control tasks, weight and energy consumption of on-board equipment, loading of nodes, etc.

Design And Development Of Power And Attitude Control Subsystems For RYESAT

This thesis describes the design and development of Ryerson University's first CubeSat (RyeSat) with a focus on power and attitude control subsystems. This satellite is intended to become the initial of a series of CubeSats built by Ryerson University to perform research in spacecraft control algorithms and actuators. RyeSat is built around a standard interface, which specifies both a data-bus and a switchable power supply system for non critical systems. To facilitate the development of this satellite a prototype power subsystem was created, programmed and tested. In addition to developing the system's architecture and power subsystem; analysis was preformed to size both reaction wheels and magnetic torquers. This analysis showed that a commercially available motor could be adapted to fulfill the attitude control requirements of a CubeSat and also showed that miniature magnetic torque rods would be more efficient that magnetic torque coils typically used on CubeSats. Finally, control laws for these actuators were designed and an adaptive nonlinear sliding mode controller for reaction wheels was applied to control the 3-axis attitude motion of RyeSat.