Development of self-propelled vertical transportation mechanism that grips and runs on rail

Abstract

In order to realize a high speed and high space use efficiency transportation system in a vertical plane, authors conceived a concept to compose the system by multiple vertical rails and multiple self-propelled loading platforms so that such platforms can independently move along each rail and transfer between them. This paper focuses on the design of drive mechanism for such a self-propelled loading platform utilizing the friction force between the rail and the driving wheels. In order to enable to generate a large grip force enough to support and move the platform with payload without using additional actuators while flat rails with small unevenness and gaps are used, the following three principles of operation are applied: the friction drive wheels with less vibration and noise, grip force generation using self-servo effect, and wheel load equalizing based on the rocker-bogie. Through the kineto-static analysis of the proposed mechanism, the relationship between the design parameters such as the angle of the self-servo link and the dimensions of the wheel load equalizer link, operating conditions such as the loading weight, the eccentricity of the center of gravity, and the inclination of the body, and the grip force and the wheel load is studied, and the design parameters and their tendency which enable to run vertically have been clarified. Furthermore, based on the knowledge obtained through the analysis, a prototype was designed, and the stable and high-speed vertical running and running over unevenness and gap has been successfully achieved. From the above, it was shown that the design of drive mechanism based on the principle proposed in this paper was effective as the mechanism that can run on flat vertical rail.

Keywords

• mechanism
• vertical transportation
• self-servo effect
• rocker-bogie mechanism
• mechanism design