Kinematic stability analysis of the tethered unmanned aerial vehicle quadrotor during take-off and landing

During take-off and landing of the tethered unmanned aerial vehicle quadrotor, some uncertain factors (e.g., ground effect and wind gusts) may lead to dynamic unstable. To address these issues, a kinematic stability analysis method for the tethered unmanned aerial vehicle quadrotor is proposed, which is based on Lyapunov exponent. The dynamical model of the tethered unmanned aerial vehicle quadrotor is achieved by Euler-Lagrange equation. The tension equation of tethered cable is deduced by catenary theory. A method is realized based on the stability determination of Lyapunov exponents and constructed the quantitative relationship between the system structure parameters and the motion stability. A physical prototype is established and the physical parameters of the system are determined by direct and indirect methods. Dynamic characteristics of the tethered unmanned aerial vehicle quadrotor are analyzed by simulation and test. Results show that the stability indices of tethered quadrotor during landing are 329.5% and 213.21% higher than those of take-off in simulation and experiment, respectively. Structural parameters of the tethered unmanned aerial vehicle quadrotor are reasonable. © 2020, Science Press. All right reserved.