This example shows a Simpson transmission with three forward speeds and one reverse speed. Two planetary gear sets are linked with a common sun gear. Two disk friction clutches and two band brakes determine which components can rotate relative to one another which determines the final gear ratio. The Clutch Schedule subsystem shows which clutches and brakes should be locked for each forward or reverse speed.
The plot below shows the speed of the input and output shafts of the Simpson 3-speed transmission. This test cycles through four gear ratios, three for forward and one for reverse. The states of the two clutches and two band brakes are also shown.