Buffering method of bio-inspired landing gear based on active compliance control

Improving the landing adaptability and buffering capability of low-altitude multirotor aircraft is crucial for ensuring safe landings in complex environments. Traditional landing gear systems are typically rigid and rely on passive damping mechanisms, which limit their ability to adapt to uneven terrain or respond actively to impact forces. This often leads to unstable landings and potential structural damage. To address these challenges, a bio-inspired legged landing gear integrating actuation and damping functions is proposed. A dynamic model encompassing both the landing gear and the aerial vehicle is established. Based on this model, an active compliance control strategy is formulated using impedance control principles, enabling tunable stiffness and damping characteristics. This approach enhances terrain adaptability while significantly improving shock absorption performance during landing. To verify the rationality of the landing gear design and the effectiveness of the control method, studies were conducted under various landing conditions, including a 200 mm height difference terrain, a 15° sloped terrain, and different lateral landing velocities of 0.5, 1.0, 1.5 m/s and 2.0 m/s. The results indicate that, compared to the non-buffered approach and the traditional joint motor-based triple-loop control buffering strategy, the active compliance control strategy reduces the peak body overload by 82.4% and 70%, the peak torque of the hip joint by 78.5% and 58.6%, and the peak torque of the knee joint by 76.7% and 67.8%. Under lateral landing conditions, the proposed method effectively absorbs lateral impact energy and enables rapid recovery of the aircraft’ s attitude.