Design and control of autonomous quad tilt rotor unmanned convertiplane

Abstract

Advancements in sensors, microcontrollers, and control technologies have led to the design and development of Unmanned Aerial Vehicles (UAV) with more complex and inherently unstable configurations in recent years. The two types of conventional UAV configurations, fixed wing and Vertical Takeoff and Landing (VTOL) UAVs, dominate the commercial and miniature UAV segments. These two types have their own merits and demerits in terms of endurance, cruising speed, payload, takeoff, and landing capability. A new type, the hybrid convertible UAV, is getting popular recently as it integrates the beneficial features of both fixed wing and VTOL configurations. The challenging task in the design of a Vertical Takeoff Horizontal Transition (VTHT) type convertible vehicle is the smooth transition from rotary wing to tandem wing flight during takeoff and vice-versa during landing. Hence, the research proposes a Quad Tilt Rotor Unmanned Convertiplane (QTR-UC) design with a simple and dedicated quad-tilt mechanism, a smooth transition control scheme, a modified PID (model-free) controller, and an Augmented LQI (model-based) controller for autonomous control. newlineThe proposed QTR-UC combines both the tandem wing configuration and the quadcopter configuration with a tilt mechanism. Most commercial flight controllers use PID controllers for stabilisation and control of UAVs, so the PID controller is modified and proposed as a PIR controller. The modification is made in the derivative part of the PID controller by replacing the derivative part with rate control, and a fraction of the error is considered as the desired rate. A similar rate control scheme is augmented with the conventional LQI controller. newline