Caltech WAVE

Design, fabrication, and control of a 2-DOF gimbal system for UAV altimetry sensing.

Two-DOF Gimbal for Altimetry Sensing on UAVs

During my WAVE Fellowship at Caltech, I worked in the Amber Lab where I designed, fabricated, and programmed a two-axis gimbal system to support research on safety-critical control for UAVs. This work was completed under the supervision of Professor Aaron Ames.

The gimbal was mounted on the underside of a UAV platform and was actuated through two servos providing its degrees of freedom. I fabricated the components and integrated a custom PCB with LiDAR, ultrasonic, and barometric sensors for altimetry sensing. On a second PCB, a Teensy 3.2, paired with an IMU, provided real-time servo control. The controller was a simple PD controller that adjusts the gimbal’s desired pitch and roll angles to maintain a stable orientation relative to the ground during flight.

Gimbal mounted on the underside of the UAV. The lidar and ultrasonic sensors aim at the ground to compute distance.
Right: the white PCB contains a 1D LiDAR, ultrasonic sensor, barometer, and IMU. Left: the red PCB contains the Teensy 3.2 that interfaces with the servos, sensors, and computes the control action.
The final gimbal design (left) and the control diagram (right) illustrating the simple yet effective state-feedback loop between the sensors and servos.

Video Demonstration