A Discrete Approach to Feedback Linearization, Yaw Control of an Unmanned Helicopter

Mohammadzaheri, Morteza and Khaleghifar, Arman and Ghodsi, Mojtaba and Soltani, Payam and AlSulti, Sami (2022) A Discrete Approach to Feedback Linearization, Yaw Control of an Unmanned Helicopter. Unmanned Systems. ISSN 2301-3850

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Nonlinear control laws often need be implemented with digital hardware. Use of digital control systems leads to communication/processing delays which are widely neglected in control of mechanical systems. This paper proposes a discrete approach to feedback linearization that considers these commonly overlooked delays in design. The proposed approach is shown to both improve the performance and remove the need for continuous derivative terms. In feedback linearization control systems designed in continuous domain, derivative terms are required to speed up the control response of mechanical systems, but disadvantageously cause high sensitivity to noise. The proposed approach was used to design a feedback linearization control system for a common turning manoeuvre of an unmanned helicopter in yaw. At this manoeuvre, the helicopter centroid motion and pitch rotational speed are almost zero. Governing differential equations of the helicopter at this manoeuvre are nonlinear and coupled. A feedback linearization law was proposed to curb nonlinearity and a discrete control system, considering the inevitable delay due to use of digital control systems, was adopted to complete the control law. This innovative approach resulted in less sensitivity to noises and performance boost. Practical limits in terms of control input, rotor speed, sampling frequency and noises of the gyroscope, the tachometer and the acceleration sensor were taken into account in this research. The results show that the proposed control system leads to fast and smooth yaw turns even at a high pitch angle (close to vertical) or in the case of being hit by external objects.

Item Type: Article
Identification Number: https://doi.org/10.1142/S2301385023500012
12 February 2022Accepted
18 April 2022Published Online
Uncontrolled Keywords: Feedback linearization, discrete control systems, delay, noise sensitivity, unmanned helicopters, yaw angle
Subjects: CAH10 - engineering and technology > CAH10-01 - engineering > CAH10-01-01 - engineering (non-specific)
CAH10 - engineering and technology > CAH10-01 - engineering > CAH10-01-02 - mechanical engineering
CAH10 - engineering and technology > CAH10-01 - engineering > CAH10-01-08 - electrical and electronic engineering
Divisions: Faculty of Computing, Engineering and the Built Environment > School of Engineering and the Built Environment
Depositing User: Morteza Mohammadzaheri
Date Deposited: 15 Feb 2022 11:30
Last Modified: 18 Apr 2023 03:00
URI: https://www.open-access.bcu.ac.uk/id/eprint/12843

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