Showing papers by "Rogelio Lozano published in 2021"

PVTOL control using feedback linearisation with dynamic extension

Abstract: The problem of controlling Unmanned Aerial Vehicles (UAV) can be simplified in some cases by designing a controller for the Vertical Take-off and Landing (PVTOL) platform and adapting it to other v...

Automated Agave Detection and Counting Using a Convolutional Neural Network and Unmanned Aerial Systems

Abstract: We present an automatic agave detection method for counting plants based on aerial data from a UAV (Unmanned Aerial Vehicle). Our objective is to autonomously count the number of agave plants in an area to aid management of the yield. An orthomosaic is obtained from agave plantations, which is then used to create a database. This database is in turn used to train a Convolutional Neural Network (CNN). The proposed method is based on computer image processing, and the CNN increases the detection performance of the approach. The main contribution of the present paper is to propose a method for agave plant detection with a high level of precision. In order to test the proposed method in a real agave plantation, we develop a UAV platform, which is equipped with several sensors to reach accurate counting. Therefore, our prototype can safely track a desired path to detect and count agave plants. For comparison purposes, we perform the same application using a simpler algorithm. The result shows that our proposed algorithm has better performance reaching an F1 score of 0.96 as opposed to 0.57 for the Haar algorithm. The obtained experimental results suggest that the proposed algorithm is robust and has considerable potential to help farmers manage agave agroecosystems.

Design, Construction, and Control for an Underwater Vehicle Type Sepiida

Abstract: A novel underwater vehicle configuration with an operating principle as the Sepiida animal is presented and developed in this paper. The mathematical equations describing the movements of the vehicle are obtained using the Newton–Euler approach. An analysis of the dynamic model is done for control purposes. A prototype and its embedded system are developed for validating analytically and experimentally the proposed mathematical representation. A real-time characterization of one mass is done to relate the pitch angle with the radio of displacement of the mass. In addition, first validation of the closed-loop system is done using a linear controller.

Modeling and Control of a Single Rotor Composed of Two Fixed Wing Airplanes

Abstract: This paper proposes a simple flying rotor prototype composed of two small airplanes attached to each other with a rigid rod so that they can rotate around themselves. The prototype is intended to perform hover flights with more autonomy than existing classic helicopters or quad-rotors. Given that the two airplanes can fly apart from each other, the induced flow which normally appears in rotorcrafts will be significantly reduced. The issue that is addressed in the paper is how this flying rotor prototype can be modeled and controlled. A model of the prototype is obtained by computing the kinetic and potential energies and applying the Euler Lagrange equations. Furthermore, in order to simplify the equations, it has been considered that the yaw angular displacement evolves much faster than the other variables. Furthermore a study is presented to virtually create a swashplate which is a central mechanism in helicopters. Such virtual swashplate is created by introducing a sinusoidal control on the airplanes’ elevators. The torque amplitude will be proportional to the sinusoidal amplitude and the direction will be determined by the phase of the sinusoidal. A simple nonlinear control algorithm is proposed and its performance is tested in numerical simulations.

Least Airspeed Reduction Strategy & Flight Recuperation of a Fixed-Wing Drone

Abstract: An energy reduction strategy for a fixed-wing drone with classic configuration is presented in this paper. The strategy is developed using the longitudinal non-linear motion equations of the aircraft, considering the stall effects in the determination of lift and drag forces. Our strategy imposes the aircraft to track a special trajectory allowing the vehicle to perform a curve in ascend, acting against the gravity force. As a consequence of this tracking, the angle of attack of the vehicle is increased arriving to critical values that need to be compensated for avoiding the crash of the vehicle. Therefore, a strategy to avoid the stall stage and recovering the flight stability in the vehicle is proposed. The strategy is evaluated in simulations for validating the performance of the whole system.

PVTOL global stabilisation using a nested saturation control

Abstract: This paper presents how the nested saturation control introduced in Teel (1992) can be modified to stabilise the model of the Planar Vertical Take-Off and Landing (PVTOL) system. A particular choic...