Research On CVT Oriented To Small Mobile Robots

Small mobile robots have a wide range of applications on both the military andcivilian. Transmission acts as a key part of small mobile robot drive,which has adecisive impact on speed, efficiency and load capacity. CVT can continuouslychange the transmission ratio，so it has the advantage of making small mobilerobots adjust to complex road conditions. However, a small mobile robot requiresthat the CVT should have small size and light weight, which make most of theexisting CVT not able to be used directly. There is rare study on CVT oriented tosmall mobile robots in either China or other countries. Besides, transmission abroadcosts too much and is uneasy to purchase. So it is meaningful and necessary to doresearch on CVT oriented to small mobile robots. The main purpose of this paper isto designing and doing research on CVT that can be used on small mobile robots andto conducting quasi-static analysis, modal analysis, thermal structure couplinganalysis and performance testing.Firstly, based on the theory of face friction, the structural of CVT was designed,including the main drive, the clamping device, and the speeder. In order to makeface friction drive well used in the CVT, a new ferry was designed, so that thedriving force could be reduced. The rolling friction was analyzed and calculated,and the calculation of time to promote was deduced.Secondly, we conducted quasi-static analysis, modal analysis, and thermalstructure coupling analysis on the face friction of CVT. The qualitative analysisduring friction drive was done and a suitable model for calculating the friction wasfound. The quasi-static analysis of main components was done.Then results of thecontact stress and strain diagram were got, showing that strength and stiffness ofmaterial were enough. The finite element method was used to get ten naturalfrequencies and mode shapes of key components of friction drive. It was proved thatfriction drive can adapt well to complex vibration of small mobile robots.Temperature field was studied. Then a thermal structure coupling analysis wasconducted. It showed that the effect thermal loads have on friction drive was notsignificant. Above analysis provided basis for application of face friction drive.At last, the corresponding test units were designed. The tests of transmissionvolume, weight, speed ratio, speed time, the maximum output torque werecompleted. Besides, the effects that the speed ratio, input speed and drag torquehave on transmission efficiency were analyzed.Theresults proved that theperformance of CVT met the requirements.This paper proved that the CVT based on face friction could be applied to small mobile robot. And it can help the further study of CVT used on small mobile robotand face friction drive.