In context
In 2023, aerial manipulators were expanding from passive inspection to physical contact tasks such as non-destructive testing and surface cleaning. Conventional under-actuated multirotors could not generate lateral thrust without tilting the fuselage, limiting their ability to maintain stable contact while moving along a surface. This paper from Southeast University addressed that gap by designing a fully actuated rotor platform.
What was reported
Researchers built a fully actuated six-rotor aerial manipulator with each power unit tilted by 30° to produce non-parallel thrust directions. A control allocation matrix confirmed full actuation (rank 6), enabling decoupled position and attitude control. The system used a cascaded P-PID controller for both loops.
For contact operations, they proposed a hybrid force/motion controller that splits the task into an approach phase and a moving-contact phase. A laser rangefinder measured distance, and a single-axis force sensor at the end effector fed contact force measurements. The controller achieved force regulation along the surface normal while sliding along the surface.
Outdoor experiments showed the platform maintained attitude within ±1.5° during flight, and position changes did not require attitude changes—a key advantage over under-actuated designs. Contact force control was demonstrated during moving contact at different lateral speeds and desired forces.
Why it mattered
This work advanced aerial manipulation by decoupling position and attitude, enabling more precise and stable physical interaction. The ability to control contact force while moving along a surface is critical for tasks like ultrasonic inspection or cleaning, broadening the practical use of drones in industrial maintenance and infrastructure monitoring.
“The position change during flight doesn't depend on attitude change, and the attitude angle is kept within ±1.5°.”
Source: 《机器人》期刊 (robot.sia.cn) · Published 2023-09-16 · “一种用于接触作业的全驱动旋翼飞行机械臂设计与实现”