In 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.
This 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.
The antilock braking system (ABS) is a mechatronic system that helps a driver maintain the maneuverability of a vehicle while braking by preventing wheel lock-ups. However, the design of high-performance controllers for this type of system is complicated because of its highly nonlinear dynamics. The problem becomes even more difficult to resolve when uncertainties in the parameters appear in its dynamics. In this paper, an ABS laboratory setup mimicking a quarter car model is considered. A modified high-order sliding mode (HOSM) controller using a proportional–integral–differential (PID) control as a sliding surface was designed. This controller provides a reference value of a tire slip. The proposed controller uses a tracking error to define the slip surface through the PID controller structure, and the modified HOSM controller holds the system on the previously designed slip surface. The closed-loop system stability has been proven in the sense of Lyapunov. Finally, the ABS laboratory setup allows for experimentally checking the performance of the modified HOSM controller using a PID-sliding surface, showing a considerable increase in the efficiency of the control system compared with a PID-like controller.
Despite the increasing use of unmanned aerial vehicles (UAVs) for pest control, there are still possibilities to optimize the spraying process by selecting the flight parameters of the operations involved, such as flight speed and height, according to the penetration of droplets that is sought to have in the corn plant. In this research, the flight parameters that the operators should select according to the type of disease they treat in corn crops were determined. To achieve this, first, a survey of the main diseases that attack corn crops in the region was carried out along with their location in the plant. Subsequently, flight tests were carried out selecting speeds of 2.80, 4.75, and 5.97 m/s and heights of 2.00, 2.75, and 3.50 m. The plants’ cover rates at the three different heights (top, middle, and bottom) were collected by hydrosensitive strips and scanned by the SnapCard scanning software. The use of statistical techniques allowed understanding the impact that flight parameters had on the coverage rate and droplet penetration: the higher the speed, the lower the coverage rate in the upper part of the plant and the higher the coverage rate in the lower part. On the other hand, the lower the height, the higher the coverage rate and droplet penetration.
La industrialización del sector agrícola ha provocado el aumento del uso de sustancias químicas especialmente utilizadas en tierras agrícolas, por sus beneficios en el aumento de productividad y el manejo de enfermedades en las plantas. La actividad que más utiliza los plaguicidas es la agricultura, consumiendo el 85% de la producción mundial, por ello la evolución de la maquinaria agrícola es vital para satisfacer los requisitos del mercado. Sin embargo, los numerosos efectos secundarios causados por la alta exposición ocupacional a equipos poco funcionales implican un alto riesgo en la salud del trabajador, el cual está expuesto principalmente a elementos como posturas forzadas y manipulación manual de cargas de maquinaria pesada durante tiempos prolongados. En este estudio se analizó el efecto que tiene la manipulación de cargas pesadas sobre los movimientos angulares del ciclo de la marcha y fatiga, enfocada en el manejo de tres tipos de aspersores agrícolas en distintos estudiantes masculinos. Se realizaron pruebas de marcha de 75 minutos sobre terreno de césped natural con distintas cargas de peso y durante una caminata normal sin peso extra.
Se colocaron goniómetros sobre ambas rodillas de los sujetos analizados para obtener la velocidad y el ángulo de la marcha. La fatiga se calculó para evaluar el impacto que tiene la manipulación de cargas sobre la marcha. Los resultados mostraron que durante el análisis de la marcha con peso y sin peso hay una diferencia notoria en el rizo que crea la fase del apoyo del caminado, por el peso que genera el aspersor agrícola sobre la espalda y a su vez sobre las rodillas; esto se debe al cambio de postura, forzada por la manipulación de cargas pesadas sobre la espalda. Los resultados se enfatizan cuando el sujeto analizado tiene sobre peso y no practica ningún tipo de deporte.
The antilock braking system (ABS) is an electromechanical device whose controller is challenging to design because of its nonlinear dynamics and parameter uncertainties. In this paper, an adaptive controller is considered under the assumption that the friction coefficient is unknown. A modified high-order sliding-mode controller is designed to enhance the controller performance. The controller ensures tracking of the desired reference and identifies the unknown parameter, despite parametric variations acting on the real system. The stability proof is done using the Lyapunov approach. Some numerical and experimental tests evaluate the controller on a mechatronic system that represents a quarter-car model.
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