41 research outputs found
Nonlinear Output Robust Regulation of Ground Vehicles in Presence of Disturbances and Parameter Uncertainties
No full text
Design of a NonLinear Observer for a Laboratory Antilock Braking System
No full textIn this paper a nonlinear observer is presented in order to estimate the angular velocity of both upper and lower wheels of a PC controlled ABS Laboratory setup, from Inteco Ltd. The system simulates the dynamics of a quarter car model. In order to accomplish this, it includes two attached wheels. The angular velocity of the upper wheel simulates the angular velocity of a vehicle's wheel, while the lower wheel simulates the road surface. In the observer design, it is assumed that the angular velocity of the vehicle's wheel is known, since a sensor is installed on the system, as in a real vehicle, so that the longitudinal velocity can be determined with this information. The proposed nonlinear observer considers the Pacejka's "magic formula" to calculate the contact force. This formula allows the observer to estimate the states in both the linear and nonlinear regions. The stability of the observer is proved and validated with simulations, and experimentally with the Antilock Braking System Laboratory setup
Experimental comparison of linear and nonlinear controllers applied to an Antilock Braking System
No full textReal-Time Hovering Control of Unmanned Aerial Vehicles
No full textIn this paper, the design of a controller for the altitude and rotational dynamics is presented. In particular, the control problem is to maintain a desired altitude in a fixed position. The unmanned aerial vehicle dynamics are described by nonlinear equations, derived using the Newton-Euler approach. The control problem is solved imposing the stability of the error dynamics with respect to desired position and angular references. The performance and effectiveness of the proposed control are tested, first, via numerical simulations, using the Pixhawk Pilot Support Package simulator provided by Mathworks. Then, the controller is tested via a real-time implementation, using a quadrotor Aircraft F-450
Vision-Based Nonlinear Control of Quadrotors Using the Photogrammetric Technique
No full textThis paper presents a controller designed via the backstepping technique, for the tracking of a reference trajectory obtained via the photogrammetric technique. The dynamic equations used to represent the motion of the quadrotor helicopter are based on the Newton-Euler model. The resulting quadrotor model has been divided into four subsystems for the altitude, longitudinal, lateral, and yaw motions. A control input is designed for each subsystem. Furthermore, the photogrammetric technique has been used to obtain the reference trajectory to be tracked. The performance and effectiveness of the proposed nonlinear controllers have been tested via numerical simulations using the Pixhawk Pilot Support Package developed for Matlab/Simulink
Robust Nonlinear Control of a Wind Turbine with a Permanent Magnet Synchronous Generator
No full textThis paper addresses the design of a robust nonlinear dynamic controller for a wind turbine. The turbine is equipped with a permanent magnet synchronous generator. The control problem involves tracking a suitable reference value for the turbine’s angular velocity, which corresponds to the wind speed. This issue is tackled by compensating for variations in the electrical and mechanical parameters present in the mathematical model. Additionally, the problem is approached under the assumption that wind speed cannot be directly measured, a fact verified in practical scenarios. This situation is particularly relevant for real-world applications, where only nominal parameter values are accessible and accurate wind speed measurement is challenging due to disturbances caused by the turbine or other factors, despite the use of appropriate sensors. To achieve precise tracking of the angular velocity reference, effective compensation of perturbation terms arising from parameter uncertainties and errors in wind estimation becomes crucial. To address this problem, a wind velocity estimator is employed in conjunction with high-order sliding mode parameter estimators, ensuring the turbine’s operation attains a high level of performance
Event-Triggered linear control design for an Antilock Braking System
No full textEvent-Triggered control is a resource-aware sampling strategy that updates the control value when a certain condition is satisfied, which denotes event instants. Such technique allows to reduce the control computational cost and communications. In this paper an Event-Triggered linear control for an Antilock Braking System is developed and simulated using the mathematical model of the ABS laboratory setup, manufactured by INTECO. The proposed feedback ensures the asymptotically stability of the ABS
