A research team from South Korea has introduced the Palletrone Cart, a fully actuated multirotor aerial vehicle designed for direct physical interaction with a human operator during cargo transportation. The system enables the operator to guide the drone by holding a handle attached to its rear, applying motion forces to control its movement.

Design and Control Approach

The Palletrone Cart is designed to maintain a level attitude while moving in three-dimensional space. Instead of using force sensors, it employs an admittance controller combined with a disturbance observer (DOB) to estimate the forces applied by the operator. This allows the drone to interpret human-applied forces and adjust its trajectory accordingly.

Testing and Results

The research team conducted three experiments to evaluate system performance:

1. Directional Movement Control: The drone was moved along specific axes, including yaw rotation, while resisting roll and pitch motions.

2. Controller Parameter Variation: Changes to the virtual inertia and damping parameters in the admittance controller affected the responsiveness and smoothness of the drone’s movements.

3. Cargo Transport Along Arbitrary Paths: With a payload of approximately 3 kg, the drone followed operator-guided paths while maintaining a stable, level orientation.

Potential Applications

The design is aimed at cargo transportation in environments where wheeled systems may not be effective, such as uneven terrain or areas with obstacles.

Limitations and Future Work

The current implementation assumes disturbances originate from the human operator and does not account for environmental factors such as wind. Future work will focus on distinguishing between human intention and environmental interactions, introducing quantitative evaluation methods, and applying optimization-based control strategies.