Design and Joint Control of a Conjoined Biplane and Quadrotor.

The article focuses on the design and joint control of a novel conjoined aerial system combining a hybrid biplane and a quadrotor unmanned aerial vehicle (UAV) capable of cooperative joint hover, joint forward flight, and in-flight separation for independent operation. The study proposes control strategies for the quadrotor that operate without communication with the biplane, relying solely on onboard sensors, and compares three approaches: constant thrust, proportional angular rate damper, and proportional angular acceleration damper. Experimental results demonstrate that the angular rate damper strategy offers improved disturbance rejection with minimal performance degradation and lower control input demands compared to the other strategies, while the in-flight release mechanism reliably enables separation up to a forward pitch angle of 18°. The research highlights the trade-offs of communication-free cooperative control and suggests future work on forward flight dynamics and potential benefits of inter-vehicle communication.