GearDrivingVariables is an option for DefinePlanetaryGear function. It specifies the joint variables of the sun, cage and ring links of the planetary gear.
The option is defined as GearDrivingVariables->{q1,q2,q3} where the first variable(q1) specifies the joint variable of the sun gear, the second variable(q2) the cage gear and finally q3 defines the joint variable of the ring gear.
