Velocity variation system for mobile robot

Abstract

A wide range of speed or torque is required for some types of machines. It is possible for the motors to realize some range of speed or torque but the range is limited to some degree considering the size, weight and cost of the motors. If the velocity ratio between input and output shaft is changed, a wide range of speed or torque can be realized even if the ability of the motor is limited in speed or torque. Therefore a velocity ratio variation system is an ideal method in this point. Ratio variation devices using gears are widely used in the industrial fields and there are many research reports in terms of device control and mechanisms. Gears have advantages in torque capacity, precise rotation transmission and efficiency and that is the reason why gears are used in a variety of mechanical devices. In a geared transmission, it is necessary to change the working gear pairs to vary the velocity ratio of the transmission. However, the motion transmission from the input shaft to the output shaft is interrupted during this process. Therefore it is impossible to change the velocity ratio while transmitting rotation between the input and output shafts. This leads to an important problem in the field of precise positioning. In order to solve this problem, the velocity ratio variation method that can transmit motion precisely is proposed in this report. This method uses a gear pair that can realize the velocity ratios of two gear pairs to transmit motion precisely. In this report, the principle of this velocity ratio variation method is proposed and its components are considered. In addition, to reveal the geometrical characteristic of the element for this system, the analysis program of the geometry of the element is developed.