Prototype Development and Flight Controller Implementation of the Sliding-Arm Quadcopter

Abstract

In this paper, the design, development, and flight testing of the technology demonstration prototype for the sliding arm quadcopter are described. Furthermore, details on the hardware component design, machining, and integration of various UAV subsystems are discussed. The sliding arm UAV is a shape changing aerial robot design that has additional servo motor inputs for actuating the length of the quadcopter's arms. The additional servo motors are actively controlled using proportional derivative (PD) control. The PD based control is implemented using an onboard Raspberry Pi computer which utilizes the command and feedback data from the UAV autopilot through the ROS/MAVROS middleware interface. This methodology shows the feasibility of integrating and accommodating the extra servo inputs in the existing Pixhawk firmware. The functionality of the technology demonstration prototype is validated via successful static bench tests paired with indoor and outdoor flight tests. Additionally, the UAV has been flight tested in both manual and semi-autonomous flight modes using an open source ground control station. The flight performance of various flight parameters and the new servo motor parameters have also been presented.