To improve the flight stability of quadcopters in interference-prone environments, the under actuated strong coupling and nonlinear characteristics of the system were fully considered, and a dual closed-loop control system based on the adaptive super-twisting sliding mode method was proposed. First, the control system was structured into an outer loop for position control and an inner loop for attitude control, both designed using the super-twisting sliding mode control method, effectively reducing the chattering typically caused by conventional sliding mode control approach. Then, an adaptive disturbance compensation law was introduced to counteract unknown external disturbances, enabling the controller to maintain the stability of the closed-loop system with reduced control gain, thereby further minimizing chattering. Finally, the stability of the proposed control system was theoretically validated using Lyapunov stability theory, and its performance was verified through simulations conducted in MATLAB. The simulation results show that the designed control system offers strong robustness, high control accuracy, and effective trajectory tracking performance while significantly suppressing system chattering.

Compared with traditional wheeled and footed robots, spherical tensegrity robots offer advantages such as a high strength-to-mass ratio, excellent cushioning performance, and superior terrain adaptability, making them highly promising for deep space exploration. While cable-driven modes are commonly used for tensegrity robots, the excessive number of actuators requires for walking complicates manufacturing and control. This study proposes a novel driving mode based on the post-buckling deformation of flexible rods. Numerical simulations of the walking process of a spherical tensegrity robot are conducted, and the efficiencies of cable-driven and rod-post-buckling-driven modes are compared. The exact solution for the post-buckling deformation of a single rod is obtained using the elliptic integral method. Based on this, a rigid-flexible coupling dynamics simulation model of the spherical tensegrity robot is established in ADAMS, with considering the post-buckling deformation of the rods, as well as contact and friction. The walking gait of the spherical tensegrity robot is determined through joint simulation using ADAMS and Simulink software, employing a greedy search algorithm. A control system model is established in Simulink to facilitate the robot ’ s walking control to any target points under the rod-post-buckling-driven mode. Compared to the conventional cable-driven mode, the post-buckling-driven mode reduces the number of actuators required for continuous robot walking from 18 to 6 and increases the walking speed by 43.78%. The results provide theoretical guidance for the design and manufacture of new tensegrity robots.

To address the impact of materials with uneven mass distribution on the motion of double pendulum systems in engineering practice, a heterogeneous double pendulum model was established based on the homogeneous physical double pendulum model. This model incorporated variables, such as the position of the center of mass and the moment of inertia of the pendulum. To further explore the chaotic characteristics of the system, the heterogeneous double pendulum system was approximated from a Hamilton system to a quasi-Hamilton system. The dynamics equation of the double pendulum system was obtained using the Euler-Lagrange equation of the second kind. The energy threshold for Smale horseshoe chaos in the quasi-Hamiltonian system was determined using Melnikov method with two degrees of freedom, serving as the chaos condition for the Hamiltonian system. Through programming in Matlab, the correctness of the chaos condition was verified using numerical methods such as maximum Lyapunov exponential diagram, bifurcation diagram and Poincare section diagram. The influence of each parameter on the system’s motion state and action mechanism was analyzed in detail. The results show that the chaos threshold of heterogeneous double pendulums depends on various factors, including the initial energy of the double pendulums, the position of the center of mass of the first pendulums and the ratio of the moment of inertia of the two pendulums. With different values for each parameter, the system changes from a regular motion state with a chaos threshold to an irregular and complex motion state without a chaos threshold. The reasons for the system alternating between chaotic and quasi-periodic states were explained, and theoretical predictions were validated. The differences between the theoretical threshold and actual numerical simulation results were explained when the center of mass of the first pendulum, the mass ratio of the two pendulums, and the ratio of moment of inertia of the two pendulums were set to their limit values. On this basis, the relationship between parameter values and the applicability of Melnikov method were further explored, and the parameters under which Melnikov method was no longer applicable were discussed by numerical simulation classification.