Abstract:
To understand the decelerating and spinning characteristics of vortex ring parachute, increase the decelerating and spinning efficiency of rotating parachute system, and satisfy the harsh demand of limiting falling speed and rotating speed for some payloads at specific working state, a compound parachute system composed of a circle drag parachute and a vortex ring parachute was designed. The test models of single parachute system and compound parachute system were made out, and then two tower tests were carried out separately. Based on high speed photography of parachute tower test and image processing technology, the trajectory data points of the parachute-payload system were extracted. Combining with the trajectory model, the time and trajectory data was fitted by least square method, the limiting falling speed and the resistance characteristics of the system were obtained. Using attitude memory-measuring technology, the rotating speed changing law of parachute-payload system was gained. The trajectory laws and the decelerating and spinning efficiency of the vortex ring parachute and the compound parachute system were analyzed contrastively, and then the method to increase the ratio of rotating speed and limiting falling speed availably was proposed. The results show that through processing the pictures shot by high-speed camera, the limiting falling speed and resistance characteristics of the parachute-payload system can be extracted quickly and efficiently. The single vortex ring parachute could provide bigger torque so that the rotating accelerating of the payload is higher, which means that the spinning efficiency is better. The compound parachute could bigger resistance so that the limiting falling speed of the payload is lower, which means that the decelerating efficiency is better. The radio of rotating speed and falling speed of compound parachute system is bigger than that of single parachute system, which means that the whole performance of compound parachute system is better.