To address the strong nonlinearity, high coupling, and time-varying parameters of Unmanned Aerial Vehicle (UAV) all-electric braking systems, this paper proposes a hierarchical PID control strategy. The control parameters are adjusted in different stages according to the slip ratio to improve the aircraft's deceleration performance. First, models of aircraft ground taxiing dynamics, wheel dynamics, tire-runway friction, and all-electric actuators were developed in Simulink. Furthermore, a predictive model for the brake disc friction coefficient is established using a Genetic Algorithm (GA)-optimized BP neural network, accounting for its real-time variations with temperature and braking pressure. A hierarchical PID control system comprising baseline braking, dynamic adjustment braking, and anti-skid braking is then designed. Through simulation analysis, a comparative study was conducted on the control performance of PD+PBM control and hierarchical PID control. Experimental verification of the hierarchical PID control strategy is also carried out on a ground inertia test bench. The results demonstrate that the proposed hierarchical PID method achieves superior control performance. The error between simulation and experimental results is within 11%, validating both the correctness of the simulation model and the effectiveness of the control strategy. The hierarchical PID controller exhibits satisfactory performance, enabling the aircraft to attain high deceleration rates under various operating conditions. Even under the most extreme and adverse condition-a wet runway with wet brake disks-the average deceleration rate of the aircraft in both simulation and experiments exceeds 2 m/s², with an error between them within 5.58%.

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.