Parameter Research of UAV Vertical Rope-type Recovery System

Vertical rope-type recovery system is a new accurate recovery method for small fixed-wing unmanned aerial vehicles (UAV). This paper models the recovery system and finishes the simulation of recovery process. The recovery stand model of the recovery system is built by analyzing the physical essence, and the aircraft model is based on dynamics and kinematics equations as well as the mechanical characteristics of arresting rope. Finally the simulation analysis of the recovery process is completed. On the basis of the modeling simulation, the system parameters’ effect on recovery performance such as maximum resistance force, maximum overload and maximum radius has been discussed by varying each key parameter. Eventually, the pattern of how initial conditions when hitting the rope as well as the arresting rope’s stiffness and damping coefficient influence recovery performance has been researched, and the result could provide theoretical reference for the design of UAV using vertical rope-type recovery and the system in the future.

Crystalline Recovery after Activation Annealing of Al Implanted 4H-SiC

Crystalline recovery mechanism in the activation annealing process of Al implanted 4H-SiC crystals were experimentally investigated. Annealing temperature and annealing time dependence of acceptor activation and activated hole’s behavior were examined. Poly-type recovery from the implantation induced lattice disordering during the annealing was investigated. The existence of meta-stable crystalline states for acceptor activation, and related scattering centers due to annealing is reported To achieve 100% acceptor activation and to reduce strain after ion implantation, annealing at 2000°C for 10 min. was required.