scholarly journals A control allocation method based on equivalent virtual control surfaces

2011 ◽  
Vol 15 ◽  
pp. 1256-1260 ◽  
Author(s):  
Shi Jingping ◽  
Zhang Weiguo ◽  
Li Suilao
Author(s):  
Biao Xu ◽  
Di Zhou ◽  
Zhuo Liang ◽  
Guofeng Zhou

Based on L2 optimal control allocation, an autopilot design approach is proposed for the missile with aerodynamic control surfaces and reaction jets. The control system involves a control allocator and a virtual control law. A robust sliding sector with a parameter update law is proposed to deal with unmatched parameter uncertainties and unknown disturbances in the system. Then a control law is designed to produce virtual control effort signals by using the robust adaptive sliding sector. In order to distribute the virtual signals to the aerodynamic control surfaces and reaction jets on the missile, a control allocator is designed by L2 optimal control allocation strategy. Simulation results show that the missile control system tracks the acceleration command fast and smoothly. In the tracking process, aerodynamic control surfaces cooperate with reaction jets, verifying the effectiveness of the proposed approach.


2021 ◽  
Author(s):  
Thomas R. Shearwood ◽  
Mostafa R. Nabawy ◽  
William Crowther ◽  
Clyde Warsop

2010 ◽  
Author(s):  
Ari Glezer ◽  
Mark G. Allen ◽  
Anthony J. Calise ◽  
Anthony Leonard ◽  
James M. McMichael ◽  
...  

Author(s):  
Ozan Temiz ◽  
Melih Cakmakci ◽  
Yildiray Yildiz

This paper presents an integrated fault-tolerant adaptive control allocation strategy for four wheel frive - four wheel steering ground vehicles to increase yaw stability. Conventionally, control of brakes, motors and steering angles are handled separately. In this study, these actuators are controlled simultaneously using an adaptive control allocation strategy. The overall structure consists of two steps: At the first level, virtual control input consisting of the desired traction force, the desired moment correction and the required lateral force correction to maintain driver’s intention are calculated based on the driver’s steering and throttle input and vehicle’s side slip angle. Then, the allocation module determines the traction forces at each wheel, front steering angle correction and rear steering wheel angle, based on the virtual control input. Proposed strategy is validated using a non-linear three degree of freedom reduced two-track vehicle model and results demonstrate that the vehicle can successfully follow the reference motion while protecting yaw stability, even in the cases of device failure and changed road conditions.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Guan Wang ◽  
Li Li ◽  
Weihua Li ◽  
Huajun Zhou ◽  
Changbo Ma ◽  
...  

This study investigates an adaptive controller for the flexible air-breathing hypersonic vehicles (AHVs) subject to external disturbances and actuator constraints. The combination of nonlinear disturbance observer and adaptive mechanism is exploited to design an adaptive controller for each subsystem. For the velocity subsystem, an auxiliary system is employed to handle the scramjet input saturation issue. For the altitude subsystem, the magnitude/rate constraints and the dynamics of aerodynamic control surfaces are addressed by the control allocation module. Simulations show the effectiveness of the proposed control.


Aerospace ◽  
2020 ◽  
Vol 7 (10) ◽  
pp. 150
Author(s):  
Thomas R. Shearwood ◽  
Mostafa R. A. Nabawy ◽  
William J. Crowther ◽  
Clyde Warsop

Tailless aircraft without vertical stabilisers typically use drag effectors in the form of spoilers or split flaps to generate control moments in yaw. This paper introduces a novel control allocation method by which full three-axis control authority can be achieved by the use of conventional lift effectors only, which reduces system complexity and control deflection required to achieve a given yawing moment. The proposed method is based on synthesis of control allocation modes that generate asymmetric profile and lift induced drag whilst maintaining the lift, pitching moment and rolling moment at the trim state. The method uses low order models for aerodynamic behaviour characterisation based on thin aerofoil theory, lifting surface methodology and ESDU datasheets and is applied to trapezoidal wings of varying sweep and taper. Control allocation modes are derived using the zero-sets of surrogate models for the characterised aerodynamic behaviours. Results are presented in the form of control allocations for a range of trimmed sideslip angles up to 10 degrees optimised for either maximum aerodynamic efficiency (minimum drag for a specific yawing moment) or minimum aggregate control deflection (as a surrogate observability metric). Outcomes for the two optimisation objectives are correlated in that minimum deflection solutions are always consistent with efficient ones. A configuration with conventional drag effector is used as a reference baseline. It is shown that, through appropriate allocation of lift based control effectors, a given yawing moment can be produced with up to a factor of eight less aggregate control deflection and up to 30% less overall drag compared to use of a conventional drag effector.


2017 ◽  
Vol 14 (1) ◽  
pp. 172988141667814 ◽  
Author(s):  
Chao Chen ◽  
Jiyang Zhang ◽  
Daibing Zhang ◽  
Lincheng Shen

Tilt-rotor unmanned aerial vehicles have attracted increasing attention due to their ability to perform vertical take-off and landing and their high-speed cruising abilities, thereby presenting broad application prospects. Considering portability and applications in tasks characterized by constrained or small scope areas, this article presents a compact tricopter configuration tilt-rotor unmanned aerial vehicle with full modes of flight from the rotor mode to the fixed-wing mode and vice versa. The unique multiple modes make the tilt-rotor unmanned aerial vehicle a multi-input multi-output, non-affine, multi-channel cross coupling, and nonlinear system. Considering these characteristics, a control allocation method is designed to make the controller adaptive to the full modes of flight. To reduce the cost, the accurate dynamic model of the tilt-rotor unmanned aerial vehicle is not obtained, so a full-mode flight strategy is designed in view of this situation. An autonomous flight test was conducted, and the results indicate the satisfactory performance of the control allocation method and flight strategy.


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