scholarly journals A Load Transportation Nonlinear Control Strategy Using a Tilt-Rotor UAV

2018 ◽  
Vol 2018 ◽  
pp. 1-20 ◽  
Author(s):  
Guilherme V. Raffo ◽  
Marcelino M. de Almeida
Keyword(s):  
Nonlinear Control ◽  
Control Strategy ◽  
Feedback Linearization ◽  
System Modeling ◽  
Suspended Load ◽  
Sampling Frequency ◽  
Position Estimation ◽  
Pole Placement ◽  
Loop Control ◽  
Tilt Rotor

This paper proposes a nonlinear control strategy to solve the trajectory tracking problem of a tilt-rotor Unmanned Aerial Vehicle (UAV) when transporting a suspended load. For the present study, the aim of the control system is to track a desired trajectory of the aircraft with load’s swing-free, even in the presence of external disturbances, parametric uncertainties, unmodeled dynamics, and noisy position measurements with lower sampling frequency than the controller. The whole system modeling is obtained through the Euler-Lagrange formulation considering the dynamics of the tilt-rotor UAV coupled to the suspended load. As for the nonlinear control strategy, an inner-loop control is designed based on input-output feedback linearization combined with the dynamic extension approach to stabilize the attitude and altitude of the UAV assuming nonlinearities, while an outer-loop control law is designed for guiding the aircraft with reduced load swing. The linearized dynamics are controlled using linear mixed H2/H∞ controllers with pole placement constraints. The solution is compared to two simpler control systems: the first one considers the load as a disturbance to the system but does not avoid its swing; the second one is a previous academic result with a three-level cascade strategy. Finally, in order to deal with the problem of position estimation in presence of unknown disturbances and noisy measurements with low sampling frequency, a Linear Kalman Filter with Unknown Inputs is designed for estimating both the aircraft’s translational position and translational disturbances. Simulation results are carried out to corroborate the proposed control strategy.

scholarly journals Suspended Load Path Tracking Control Strategy Using a Tilt-Rotor UAV

2017 ◽  
Vol 2017 ◽  
pp. 1-22 ◽  
Author(s):  
M. A. Santos ◽  
B. S. Rego ◽  
G. V. Raffo ◽  
A. Ferramosca
Keyword(s):  
Control Strategy ◽  
Degrees Of Freedom ◽  
Unscented Kalman Filter ◽  
Equations Of Motion ◽  
Suspended Load ◽  
Path Tracking ◽  
Total System ◽  
Load Path ◽  
Tilt Rotor ◽  
Lagrange Formulation

This work proposes a control strategy to solve the path tracking problem of a suspended load carried by a tilt-rotor unmanned aerial vehicle (UAV). Initially, the equations of motion for the multibody mechanical system are derived from the load’s perspective by means of the Euler-Lagrange formulation, in which the load’s position and orientation are chosen as degrees of freedom. An unscented Kalman filter (UKF) is designed for nonlinear state estimation of all the system states, assuming that available information is provided by noisy sensors with different sampling rates that do not directly measure the load’s attitude. Furthermore, a model predictive control (MPC) strategy is proposed for path tracking of the suspended load with stabilization of the tilt-rotor UAV when parametric uncertainties and external disturbances affect the load, the rope’s length and total system mass vary during taking-off and landing, and the desired yaw angle changes throughout the trajectory. Finally, numerical experiments are presented to corroborate the good performance of the proposed strategy.

scholarly journals Feedback Linearization and Sliding Mode Control for VIENNA Rectifier Based on Differential Geometry Theory

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Xiang Lu ◽  
Yunxiang Xie ◽  
Li Chen
Keyword(s):  
Differential Geometry ◽  
Sliding Mode Control ◽  
Control Strategy ◽  
Feedback Linearization ◽  
Sliding Mode ◽  
Current Loop ◽  
Loop Control ◽  
Mode Control ◽  
Vienna Rectifier ◽  
Feedback Linearization Control

Aiming at the nonlinear characteristics of VIENNA rectifier and using differential geometry theory, a dual closed-loop control strategy is proposed, that is, outer voltage loop using sliding mode control strategy and inner current loop using feedback linearization control strategy. On the basis of establishing the nonlinear mathematical model of VIENNA rectifier ind-qsynchronous rotating coordinate system, an affine nonlinear model of VIENNA rectifier is established. The theory of feedback linearization is utilized to linearize the inner current loop so as to realize thed-qaxis variable decoupling. The control law of outer voltage loop is deduced by utilizing sliding mode control and index reaching law. In order to verify the feasibility of the proposed control strategy, simulation model is built in simulation platform of Matlab/Simulink. Simulation results verify the validity of the proposed control strategy, and the controller has a strong robustness in the case of parameter variations or load disturbances.

Coordination Control Strategy for Active and Reactive Power of DFIG Based on Exact Feedback Linearization under Grid Fault Condition

2011 ◽  
Vol 48-49 ◽  
pp. 335-344
Author(s):  
Meng Zeng Cheng ◽  
Zhen Lan Dou ◽  
Xu Cai
Keyword(s):  
Nonlinear Control ◽  
Power System ◽  
Control Strategy ◽  
Feedback Linearization ◽  
Transient Stability ◽  
Reactive Power ◽  
Control Method ◽  
Linear Quadratic Regulator ◽  
Linear Quadratic ◽  
Nonlinear Control Method

In this paper, a control strategy for operation of rotor side converter (RSC) of Doubly Fed Induction Generators (DFIG) is developed by injecting reactive power into the grid in order to support the grid voltage during and after grid fault events. The novel nonlinear control method is based on differential geometry theory, and exact feedback linearization is applied for control system design of DFIG. Then the optimal control for the linearized system is obtained through introducing the linear quadratic regulator (LQR) design method. Simulation results on a single machine infinite bus power system show that the proposed nonlinear control method can inject reactive power to fault grid rapidly, reduce the oscillation of active power and improve the transient stability of power system.

scholarly journals Comparison of Nonlinear and Linear Controllers for Magnetic Levitation System

2021 ◽  
Vol 11 (17) ◽  
pp. 7795
Author(s):  
Danica Rosinová ◽  
Mária Hypiusová
Keyword(s):  
Nonlinear Control ◽  
Discrete Time ◽  
Feedback Linearization ◽  
Magnetic Levitation ◽  
Control Design ◽  
Pole Placement ◽  
System Control ◽  
Levitation System ◽  
Magnetic Levitation System ◽  
Pole Placement Controller

Nonlinear system control belongs to advanced control problems important for real plants control design. Various techniques have been developed in this field. In this paper we compare two different approaches to a nonlinear unstable Magnetic levitation system control. The first control design approach further develops our recent results on robust discrete-time pole-placement, based on convex DR-regions. The second studied approach is based on feedback linearization and the simplified development of the corresponding nonlinear control law is provided. Both approaches are compared and evaluated. The efficiency of robust discrete-time pole-placement controller is shown as well as its competitiveness in comparison with nonlinear control for Magnetic levitation system.

A new control strategy of the filling phase for wet dual clutch transmission

2015 ◽  
Vol 230 (12) ◽  
pp. 2013-2027 ◽  
Author(s):  
Hongtao Hao ◽  
Tongli Lu ◽  
Jianwu Zhang ◽  
Bin Zhou
Keyword(s):  
Control Strategy ◽  
Feedback Linearization ◽  
Analytic Solution ◽  
Minimum Principle ◽  
Mathematic Model ◽  
Filling Pressure ◽  
Dual Clutch Transmission ◽  
Hydraulic Actuator ◽  
Loop Control ◽  
Filling Phase

The traditional filling control strategy mainly relies on a large number of calibrations and is an open loop control. In order to avoid cumbersome calibrations and improve the control precision, a systematic approach of the filling control for wet dual clutch transmission is established in this paper. First, a model of the electro-hydraulic actuator for the wet dual clutch transmissions is presented and validated by the experiments. Then, an analytic solution method is developed for the filling control. To obtain the analytic solution of the filling pressure trajectory in the filling phase, the nonlinear mathematic model for wet clutches is transformed into a model in linear space by the feedback linearization, and then the optimal filling pressure trajectory is obtained based on Pontryagin’s Minimum Principle. Furthermore, to improve the control accuracy of a variable force solenoid, a closed loop control based on adaptive generalized predictive control algorithm is applied to the developed model of the electro-hydraulic actuator to track the optimal filling pressure trajectory. The simulation results indicate that the control strategy is effective for solving the filling control problem.

scholarly journals Nonlinear Maximum Power Point Tracking Control of Wind Turbine Based on Two-Mass Model Without Anemometer

2021 ◽  
Vol 9 ◽  
Author(s):  
Jian Chen ◽  
Qun Lu ◽  
Libing Chen ◽  
Xiaohui Duan ◽  
Boping Yang ◽  
...  
Keyword(s):  
Wind Speed ◽  
Nonlinear Control ◽  
Wind Turbine ◽  
Control Strategy ◽  
Feedback Linearization ◽  
Maximum Power ◽  
Control Technique ◽  
Speed Ratio ◽  
Rotor Speed ◽  
Mass Model

A nonlinear control without using anemometer is proposed to achieve the maximum power of the wind turbine (WT) based on two-mass model in this paper. To track the maximum power points, the optimal tip speed ratio control strategy requiring to know the optimal rotor speed of the WT (ORS) is employed. To achieve the ORS, a torque observer is designed to estimate the aerodynamic torque, then the ORS can be obtained by the corresponding calculations based on the estimated torque. Due to the high nonlinearities of the WT and time-varying wind speed, a nonlinear control based on feedback linearization control (FLC) is adopted to track the ORS. In the FLC, the WT is linearized firstly, then the rotor speed controller is designed via linear control technique. The effectiveness of the proposed control strategy is verified by simulation studies. The simulation results show that, compared with the traditional PI control based on torque estimation and FLC based on wind speed estimation, the proposed control strategy provides better dynamic performances and higher power conversion efficiency.

scholarly journals Modelling And Control Of Automated Polishing/Deburring Process

2021 ◽  
Author(s):  
Liang Liao
Keyword(s):  
Feedback Linearization ◽  
Closed Loop ◽  
Control Method ◽  
Minimum Degree ◽  
Open Loop ◽  
Pole Placement ◽  
Control Performance ◽  
Nonlinear Controller ◽  
Loop Control ◽  
And Control

In this thesis, a new approach is presented for the modelling and control of an automated polishing/deburring process that utilizes a dual-purpose complaint toolhead mounted on a parallel tripod robot. This toolhead has a pneumatic spindle that can be extended and retracted by three pneumatic actuators to provide tool compliance. By integrating a pressure sensor and a linear encoder, this toolhead can be used for polishing and deburring. For the polishing open-loop control, the desired tool pressure is pre-planned based on the given part geometry. To improve control performance, a closed-loop controller is applied for pressure tracking through pressure sensing. For the deburring control, another closed-loop controller is applied to regulate the tool length through tool extension sensing. The two control methods have been tested and implemented on a polishing/deburring robot, and the experiment results demonstrate the effectiveness of the presented methods. To future improve the control performance, an adaptive controller is developed to deal with the uncertainties in the compliant tool. This control method combines the adaptive control theory with the constant stress theory of the contact model. A recursive last squares (RLS) estimator is developed to estimate the pneumatic plant model, and then a minimum-degree pole placement (MDPP) is applied to design a self-tuning controller. Afterwards, the simulation and experiment results of the proposed controller are presented and discussed. Finally, a nonlinear model of the pneumatic plant is developed. The nonlinear controller developed by using feedback linearization method is applied on the nonlinear pneumatic system of the compliant toolhead. The simulation is carried out to test the effectiveness of the pressure tracking for the polishing process.

Feedback Linearization Based Nonlinear Control Strategy of VSC-HVDC

2009 ◽  
Vol 42 (9) ◽  
pp. 308-313 ◽  
Author(s):  
Gengyin Li ◽  
Ming Yin ◽  
Ming Zhou
Keyword(s):  
Nonlinear Control ◽  
Control Strategy ◽  
Feedback Linearization

Nonlinear Control Approach of an Electromagnetic Bearing System

2014 ◽  
Vol 538 ◽  
pp. 387-393 ◽  
Author(s):  
Si Jia Liu ◽  
Yu Fan ◽  
Jun Di ◽  
Ya Jing Liu ◽  
Wei Qin ◽  
...  
Keyword(s):  
Nonlinear Control ◽  
Feedback Linearization ◽  
Degrees Of Freedom ◽  
Original System ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Pole Placement ◽  
Control Approach ◽  
Dynamic Performances ◽  
Linearized System

This paper proposes a two-electromagnet double degrees of freedom active magnetic bearing (AMB) model. Considering the nonlinearity between the electromagnetic force and the air gap, the authors put forward a nonlinear control approach based on feedback linearization which decouples and linearizes the original system. For the linearized system, pole placement strategy is used to achieve expected steady and dynamic performances. Simulation results show that this approach can successfully implement the decoupling and linearization, and is effective of different initial values.

Sign in / Sign up

Export Citation Format

Share Document