scholarly journals Integrated Attitude Control Strategy for the Asteroid Redirect Mission

2014 ◽  
Author(s):  
Pedro Lopez ◽  
Hoppy Price
Keyword(s):  
Control Strategy ◽  
Attitude Control ◽  
Asteroid Redirect Mission

Attitude control strategy for unmanned wheel-legged hybrid vehicles considering the contact of the wheels and ground

2021 ◽  
pp. 095440702110583
Author(s):  
Hui Liu ◽  
Baoshuai Liu ◽  
Ziyong Han ◽  
Yechen Qin ◽  
Xiaolei Ren ◽  
...  
Keyword(s):  
Control Strategy ◽  
Attitude Control ◽  
Lower Layer ◽  
Hybrid Vehicles ◽  
The Body ◽  
Torque Control ◽  
Whole Body ◽  
Programming Algorithm ◽  
Contact Points ◽  
Motion Generator

During patrol and surveillance tasks, attitude control is crucial for improving the terrain adaptability of unmanned wheel-legged hybrid vehicles. This paper proposes an attitude control strategy for unmanned wheel-legged hybrid vehicles, considering the contact of the wheels and ground. The proposed method can naturally achieve torque control efficiently of each joint actuator and wheel-side actuator and avoid the discrepancy between off-road terrain and stability. First, an inverse kinematics model is established to resolve the body and each joint rotation angle, and the dynamic model is built based on the multi rigid body theory, considering the contact points planning of wheel and ground. Considering the nonholonomic constraint of the structure scheme, a hierarchical real-time attitude controller for a wheel-legged vehicle is proposed. The upper layer calculates the contact points of each wheel and the ground through the quadratic programming algorithm, and the lower layer is divided into a legged motion generator and a wheel motion generator by a mathematical analysis method. Finally, the proposed method is applied to achieve the tracking and control of the whole-body trajectory. The proposed strategy can achieve the decoupling of wheeled motion generator and legged motion generator, and improve control efficiency.

Attitude Dynamics and Control of Liquid Filled Spacecraft with Large Amplitude Fuel Slosh

2016 ◽  
Vol 33 (1) ◽  
pp. 125-136 ◽  
Author(s):  
M.-L. Deng ◽  
B.-Z. Yue
Keyword(s):  
Control Strategy ◽  
Attitude Control ◽  
Large Amplitude ◽  
Lyapunov Theory ◽  
Attitude Dynamics ◽  
Equivalent Mechanical Model ◽  
Attitude Maneuver ◽  
Dynamics And Control ◽  
Fuel Slosh ◽  
And Control

AbstractThis paper focuses on the attitude dynamics and control of liquid filled spacecraft, and the large amplitude fuel slosh dynamics is included by using an improved moving pulsating ball model. The moving pulsating ball model is an equivalent mechanical model that is capable of imitating the whole liquid reorientation process, specifically for the occurrence of large amplitude slosh. This model is improved by incorporating a static capillary force and an effective mass factor. The improvements on this model are validated with previously published experiment results. The spacecraft attitude maneuver is implemented by the momentum transfer technique, and the feedback control strategy is designed based on Lyapunov theory. The effects of liquid viscosity, tank location and desired steady time on sloshing torque and control torque are investigated. The attitude control strategy applied in this paper is proved to be applicable for the coupled liquid filled spacecraft system. The obtained conclusions are useful to aid in liquid filled spacecraft overall design.

scholarly journals Attitude Blended Control for Aerospace Vehicle with Lateral Thrusters and Aerodynamic Fins

2019 ◽  
Vol 37 (3) ◽  
pp. 532-540
Author(s):  
Aijun Li ◽  
Yu Wang ◽  
Yong Guo ◽  
Changqing Wang
Keyword(s):  
Control Strategy ◽  
Finite Time ◽  
Attitude Control ◽  
Sliding Mode ◽  
Control Allocation ◽  
Sliding Mode Controller ◽  
Attitude Error ◽  
The Neural Network ◽  
And Control ◽  
Attitude Model

A finite-time blended control strategy is proposed for the reentry phase attitude control of the aerospace vehicle (ASV) based on the neural network, sliding mode control theory and control allocation. Firstly, a finite-time neural networks sliding mode controller is designed based on the attitude model of the ASV in the reentry phase to obtain the virtual control moments which can make the attitude error converge to the equilibrium point in finite time. Secondly, the desired control moments are mapped into the control commands on the aerodynamic deflectors and the reaction control system (RCS) by using the control allocation. Finally, simulation results are provided to demonstrate the effectiveness of the attitude blended control strategy proposed.

scholarly journals Advanced Autonomous Underwater Vehicles Attitude Control with L 1 Backstepping Adaptive Control Strategy

Sensors ◽  
2019 ◽  
Vol 19 (22) ◽  
pp. 4848
Author(s):  
Yuqian Liu ◽  
Jiaxing Che ◽  
Chengyu Cao
Keyword(s):  
Adaptive Control ◽  
Control Strategy ◽  
Attitude Control ◽  
Autonomous Underwater Vehicles ◽  
Euler Angle ◽  
Underwater Vehicles ◽  
Linearization Method ◽  
Backstepping Control ◽  
Feedback Form ◽  
Adaptive Control Strategy

This paper presents a novel attitude control design, which combines L 1 adaptive control and backstepping control together, for Autonomous Underwater Vehicles (AUVs) in a highly dynamic and uncertain environment. The Euler angle representation is adopted in this paper to represent the attitude propagation. Kinematics and dynamics of the attitude are in the strict feedback form, which leads the backstepping control strategy serving as the baseline controller. Moreover, by bringing fast and robust adaptation into the backstepping control architecture, our controller is capable of dealing with time-varying uncertainties from modeling and external disturbances in dynamics. This attitude controller is proposed for coupled pitch-yaw channels. For inevitable roll excursions, a Lyapunov function-based optimum linearization method is presented to analyze the stability of the roll angle in the operation region. Theoretical analysis and simulation results are given to demonstrate the feasibility of the developed control strategy.

Heliostat Attitude Control Strategy in the Solar Energy Research Facility of Valparaiso University

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Shahin S. Nudehi ◽  
G. Scott Duncan ◽  
Luke J. Venstrom
Keyword(s):  
Solar Energy ◽  
Control Strategy ◽  
Attitude Control ◽  
Tracking Error ◽  
Feedback Gain ◽  
Research Facility ◽  
Energy Research ◽  
Nonlinear Dynamic Model ◽  
Concentrated Solar Energy ◽  
Tracking Strategy

In this paper, a continuous tracking strategy for the heliostat in the James S. Markiewicz Concentrated Solar Energy Research Facility at Valparaiso University is developed. A model of the nonlinear dynamics of the heliostat motion is developed and the open-loop control strategy is presented. Asymptotic stability of the heliostat control using the Lyapunov and LaSalle’s theorems was proven. Simulations using the nonlinear dynamic model are presented and interpreted to identify the feedback gain that maximizes the time response of the heliostat without introducing oscillations in its motion. Finally, the control strategy is put to the test during summertime operation. The data presented show that the tracking strategy has an root mean square (RMS) tracking error of 0.058 mrad, where the error is defined as the difference between the desired and actual heliostat positions. Images of the aperture of a high-temperature solar receiver over 8 h of testing are also presented to qualitatively demonstrate the success of the tracking strategy.

Predictive Dynamics-Based Motion Control for the Rough-Terrain Locomotion of the Personal Vehicle Falcon-III

2011 ◽  
Vol 23 (4) ◽  
pp. 545-556
Author(s):  
Ewerton Ickowzcy ◽  
◽  
Takeshi Aoki ◽  
Shigeo Hirose ◽  
Keyword(s):  
Motion Control ◽  
Predictive Control ◽  
Control Strategy ◽  
Attitude Control ◽  
Impact Force ◽  
Dynamic Effect ◽  
Rough Terrain ◽  
Predictive Dynamics ◽  
The Impact ◽  
Motion Strategy

A predictive control strategy aiming to reduce the impact generated on a personal vehicle during obstacle negotiation is proposed. Similarly to the motion executed by a cyclist when he/she is about to negotiate a step, the motion strategy uses a dynamic effect to temporarily reduce the load on the wheel of the vehicle that must negotiate the obstacle, thus reducing the impact force as well. Such motion control strategy was developed for the three-wheeled personal vehicle Falcon-III. The vehicle behavior using the predictive control strategy was first investigated for basic cases, such as when only one of the wheels had to negotiate an obstacle; later, the strategy was generalized by combining the motion derived for the basic cases. Robustness is achieved by the use of fuzzy logic to infer the displacement of the ZMP required to negotiate different obstacles. The predictive motion control strategy was compared with a conventional feedback attitude control strategy, and was shown to produce smaller impacts than simply using the feedback strategy.

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