Browse Publications Technical Papers 2013-01-2605
2013-10-14

Servomotor Controlled Standard Automated Manual Transmission for Rapid Smooth Shifts 2013-01-2605

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-MT 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.
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 together. 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 paper also presents a detailed explanation and working of the technology that helps reduce torque interruption.
The lag in AMT shift can be easily reduced by using an external motor which comes in play as and when the clutch signal is initiated to disengage the clutch for the shifting of gear. To minimize the lag in shifting in AMT units we have developed external motor controlled low torque interruption AMT system. This paper also presents a detailed explanation and working of the technology that helps reduce torque interruption. We have reduced the timing of shifting from 600 mS to 40 mS. Thus this AMT can be a breakthrough in increasing the market of AMT in the world.

SAE MOBILUS

Subscribers can view annotate, and download all of SAE's content. Learn More »

Access SAE MOBILUS »

Members save up to 43% off list price.
Login to see discount.
Special Offer: With TechSelect, you decide what SAE Technical Papers you need, when you need them, and how much you want to pay.
X