Direct adaptive disturbance rejection and control for a deployable space telescope, theory and application

2001 ◽  
Author(s):  
R.J. Fuentes ◽  
K.N. Schrader ◽  
M.J. Balas ◽  
R.S. Erwin
Keyword(s):  
Disturbance Rejection ◽  
Space Telescope ◽  
And Control

Cascade control for heterogeneous multirotor UAS

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ayaz Ahmed Hoshu ◽  
Liuping Wang ◽  
Alex Fisher ◽  
Abdul Sattar
Keyword(s):  
Control System ◽  
Disturbance Rejection ◽  
Unmanned Aircraft ◽  
Cascade Control ◽  
Underactuated System ◽  
Content Type ◽  
Control Approach ◽  
Robust Control System ◽  
And Control ◽  
Stable Control

PurposeDespite of the numerous characteristics of the multirotor unmanned aircraft systems (UASs), they have been termed as less energy-efficient compared to fixed-wing and helicopter counterparts. The purpose of this paper is to explore a more efficient multirotor configuration and to provide the robust and stable control system for it.Design/methodology/approachA heterogeneous multirotor configuration is explored in this paper, which employs a large rotor at the centre to provide majority of lift and three small tilted booms rotors to provide the control. Design provides the combined characteristics of both quadcopters and helicopters in a single UAS configuration, providing endurance of helicopters keeping the manoeuvrability, simplicity and control of quadcopters. In this paper, rotational as well as translational dynamics of the multirotor are explored. Cascade control system is designed to provide an effective solution to control the attitude, altitude and position of the rotorcraft.FindingsOne of the challenging tasks towards successful flight of such a configuration is to design a stable and robust control system as it is an underactuated system possessing complex non-linearities and coupled dynamics. Cascaded proportional integral (PI) control approach has provided an efficient solution with stable control performance. A novel motor control loop is implemented to ensure enhanced disturbance rejection, which is also validated through Dryden turbulence model and 1-cosine gust model.Originality/valueRobustness and stability of the proposed control structure for such a dynamically complex UAS configuration is demonstrated with stable attitude and position performance, reference tracking and enhanced disturbance rejection.

scholarly journals A Robotic Head Stabilization Device for Medical Transport

Robotics ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 23
Author(s):  
Adam Williams ◽  
Bijo Sebastian ◽  
Pinhas Ben-Tzvi
Keyword(s):  
Disturbance Rejection ◽  
Experimental Validation ◽  
Traumatic Head Injury ◽  
Active Disturbance Rejection ◽  
Disturbance Rejection Control ◽  
Traumatic Head ◽  
Medical Transport ◽  
Time Required ◽  
And Control ◽  
Future Work

In this paper, the design and control of a robotic device intended to stabilize the head and neck of a trauma patient during transport are presented. When transporting a patient who has suffered a traumatic head injury, the first action performed by paramedics is typically to restrain and stabilize the head and cervical spine of a patient. The proposed device would drastically reduce the time required to perform this action while also freeing a first responder to perform other possibly lifesaving actions. The applications for robotic casualty extraction are additionally explored. The design and construction are described, followed by control simulations demonstrating the improved behavior of the chosen controller paradigm, linear active disturbance rejection control (LADRC). Finally, experimental validation is presented, followed by future work and directions for the research.

James Webb Space Telescope wavefront sensing and control algorithms

2004 ◽  
Author(s):  
Daniel S. Acton ◽  
Paul D. Atcheson ◽  
Mick Cermak ◽  
Lana K. Kingsbury ◽  
Fang Shi ◽  
...  
Keyword(s):  
Control Algorithms ◽  
Wavefront Sensing ◽  
Space Telescope ◽  
James Webb Space Telescope ◽  
And Control

Modeling and Disturbance Rejection Control of a Nanopositioner With Application to Beam Steering

2003 ◽  
Author(s):  
Jason J. Gorman ◽  
Nicholas G. Dagalakis
Keyword(s):  
Disturbance Rejection ◽  
Inertial Frame ◽  
Beam Steering ◽  
Tracking Error ◽  
Robust Tracking ◽  
Base Excitation ◽  
Modeling And Control ◽  
Disturbance Rejection Control ◽  
Motion Measurements ◽  
And Control

This paper discusses the modeling and control of a nanopositioning flexure hinge mechanism with a piezoelectric actuator. A complete dynamic model for the mechanism is presented along with experimentally determined system parameters. The control design concentrates on the problem of controlling the nanopositioner when a base excitation is injected into the system. The effects of the base excitation are overcome using two approaches. The first is a robust tracking controller which is developed to cancel the excitation effect on the tracking error. The second is an inertial compensator which is designed to update the desired trajectory using base motion measurements, such that the nanopositioner performs the desired trajectory in an inertial frame. This approach is demonstrated through simulation results. These principals are being developed for use in beam steering applications which require nanoradian resolution and very low beam jitter.

scholarly journals Developmental cryogenic active telescope testbed: a wavefront sensing and control testbed for the Next-Generation Space Telescope

1998 ◽  
Author(s):  
Claudia M. LeBoeuf ◽  
Pamela S. Davila ◽  
David C. Redding ◽  
Armando Morrell ◽  
Andrew E. Lowman ◽  
...  
Keyword(s):  
Wavefront Sensing ◽  
Next Generation ◽  
Space Telescope ◽  
And Control
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