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Servomotor Controlled Standard Automated Manual Transmission for Rapid Smooth Shifts
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 24, 2012 by SAE International in United States
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Present day AMT unit uses two high pressure hydraulically operated pistons for select & shift operations which make the unit weigh around 8kg. Besides this it also makes the unit more complex & unreliable with a lot of torque interruption. The use of electrical servo motors steps in here as a better alternative as it provides a more precise and smoother shift. To test this we used a 5 Gear-Manual Transmission. For the selection, a precise 14.5 degree of twisting was required which was easily achieved by the servo motor. Further, shift of 10.5mm could be made possible by using the motor to shift the rack using a pinion on the shaft. This system then essentially eliminates the whole hydraulic circuit, the housing of actuator pack & power pack making it a simpler unit all together. A Motor is attached to the output shaft of the Transmission which drives in power while the AMT unit is making transition from one gear to another. Thus, it offers an uninterrupted torque path from the engine to vehicle which allows for a seamless gearshift. This seminal paper provides an introduction to the technology developed.
This AMT unit is STANDARD for different transmissions as the motor can be programmed for our choice of select twist & the shift travel. A servo motor is controlled using the PIC microcontroller. A great advantage of servo motors is that they are very easy to control in comparison with other types of motors (DC, Stepper) that require an H-Bridge or external circuitry. The servo motor on the other hand has an internal circuitry. Also if the synchronizers are not properly designed and gear slip occurs or due to wear tear of synchronizers, our servo unit can be reprogrammed to further increase in travel. This prime focus of this paper is to present a detailed explanation and working of the Low Interruption Motor technology that helps reduce torque interruption.
CitationSingh, J., Singh, J., and Dhane, M., "Servomotor Controlled Standard Automated Manual Transmission for Rapid Smooth Shifts," SAE Technical Paper 2012-01-1989, 2012, https://doi.org/10.4271/2012-01-1989.
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