Development of an Interactive 3-Axis Drone Gimbal Testbench for Simulating Environmental Disturbances via Manual Excitation and Evaluating UAV Control System Parameters

Abstract

Ground testing is essential for evaluating how Unmanned Aerial Vehicles (UAVs) respond to external aerodynamic disturbances prior to deployment. This study presents the design, calibration, and evaluation of a 3-axis gimbal testbench engineered to emulate dynamic environmental disturbances and assess UAV control systems. Structurally, the platform features a dual concentric ring mechanism (1098 mm outer, 898 mm inner diameter) built from 30x30 mm T-slot aluminum, providing independent roll, pitch, and yaw degrees of freedom. A single STM32F103C8T6 microcontroller processes three LPD3806-600BM-G5 rotary encoders via external interrupts using 4x quadrature decoding, achieving a high-precision 0.15° resolution displayed on a shared 16x2 I2C LCD. Multi-axis calibration against a physical protractor validated a highly linear tracking performance, with minor deviations confined to mechanical backlash in the ring bearings. Disturbance-response testing using a manually applied 15° excitation generated peak angular deviations of 14.3°, 15.6°, and 15.3° on the yaw, pitch, and roll axes, which were closely tracked by the attitude estimate of a Pixhawkequipped UAV mounted on the testbench (13.8°, 14.6°, and 14.1° respectively), time-synchronized with the encoder log, with settling times of 2.4 s, 2.1 s, and 2.7 s. The results demonstrate that this single-microcontroller, dual-ring architecture provides precise, repeatable disturbance-response characterization and real-time angular feedback suitable for pre-flight UAV control system optimization.