This letter introduces a hybrid algorithm of deep reinforcement learning (RL) and Force-based motion planning (FMP) to solve distributed problem in dense dynamic environments. Individually, RL FMP algorithms each have their own limitations. is not able produce time-optimal paths existing solutions are collision free Therefore, we first tried improving the performance recent approaches by introducing new reward function that only eliminates requirement pre supervised (SL) step but also...

Summary This paper investigates the problem of attitude tracking control spacecraft subject to input magnitude and rate saturations. The smooth hyperbolic tangent function is used model As system non‐affine in input, an augmented plant presented facilitate development law. backstepping technique, robust adaptive approaches are applied design stability closed‐loop guaranteed by Lyapunov method. Numerical simulations demonstrate performance proposed controller. Copyright © 2015 John Wiley...

This paper considers the problem of attitude tracking control for uncertain rigid spacecraft subject to input magnitude and rate saturation (MRS). First, a smooth MRS model is proposed. Then, robust scheme designed based on backstepping finite-time disturbance observer techniques. Finally, effectiveness derived here illustrated by numerical simulations.

P RACTICAL spacecraft attitude control systems must operate in the presence of disturbances, modeling errors, and actuator limitations. These issues have been subject much research interest. Adaptive control, where unknown system parameters are estimated adaptively, is one proposed approaches for dealing with uncertainty (see, example, [1–4]). Both [1,2] deal tracking problem, but they do not treat disturbances or saturation. Reference [3] also deals problem; it includes saturation...

This study considers the problem of attitude tracking control for rigid spacecraft subject to input saturation. To address this problem, a smooth model is first proposed describe magnitude The output always in agreement with constraints imposed by actuators. Then, two finite-time schemes are designed based on derived here and homogeneous method. measurement angular velocity required scheme while it relaxed second one. Finally, effectiveness laws illustrated numerical simulations.

The concurrent position and attitude (pose) tracking of a rigid spacecraft is addressed in the presence actuator faults, mass inertia uncertainties, unknown external disturbances. control design relies on novel hybrid dual-quaternion integral sliding mode that incorporates hysteretic switching to avoid quaternion unwinding problem. On mode, pose error globally finite-time convergent. resultant law has simple structure consists nominal input, which realizes fault-free uncertainty-free case,...

Fault-tolerant attitude tracking control for rigid-flexible coupled spacecraft is studied in this article. Taking actuator faults, measurement errors of and angular velocity, unmeasured modal displacements, model uncertainties, external disturbances into consideration, an adaptive fault-tolerant designed. Then, based on the sequential Lyapunov method, stability closed-loop system analyzed showing that if velocity are bounded, then successively less conservative bounds error can be obtained.

This paper investigates the feasibility of using differential drag as a means nano-satellite formation control. Differential is caused when ballistic coefficients spacecraft in are not equal. The magnitude depends on difference and also altitude formation. AGI's Satellite Tool Kit (STK) used initially to assess drifts due for different altitudes. information then show that it feasible use A simple PID controller implemented adjusts cross- sectional areas satellites such energies orbits...

This technical note considers observer-based adaptive attitude tracking of fully actuated spacecraft with known bounds on the disturbance torques acting spacecraft. Given any and angular velocity observer ultimate estimation errors, sequences successively less conservative errors are obtained.

In this paper, attitude coordination control for flexible spacecraft formation flying (SFF) is investigated in the condition that common reference only available to a subset of followers group. Measurement errors, immeasurable modal variables, external disturbances and model uncertainties both rigid dynamics are addressed concurrently. Then based on sequential Lyapunov method, successively less conservative performance bounds can be obtained with proposed distributed controller.

This paper addresses the control of spacecraft hovering about uniformly rotating asteroids using only position measurements. The highly uncertain dynamical environments and absence velocity feedback make it a challenging issue. To overcome difficulties, an extended state observer is designed to estimate perturbations simultaneously. It ensures ultimately bounded estimation errors, irrespective law applied. A velocity-free controller then obtained by driving full-state with estimates from...

The spacecraft attitude estimation is addressed in the framework of invariant Kalman filtering, which rests on invariance system dynamics and output map with respect to appropriate coordinate transformations. available measurements are assumed be angular velocity from three-axis gyroscopes vector sensors. Two continuous-discrete quaternion filters developed state errors defined inertial frame body frame, respectively. former termed right-invariant extended filter latter left-invariant...