Faulty clutch and transmission configurations generate many driveline motion failures and usually arise from DoF conflicts and errors. Clutches impose conditional or dynamic constraints.
To avoid or solve such problems, pay close attention to the collective state of your clutches, including clutches occurring inside transmission subsystems. The key to avoiding errors with transmissions is to work out and implement a complete and consistent clutch schedule.
Common mistakes include:
Locking too many clutches simultaneously, leading to redundant dynamic constraints and overconstrained (not enough) DoFs.
Locking conflicts among clutches, leading to nonredundant but still conflicting constraints.
Example: Locking one clutch locks one driveline axis to another. You could also lock the first driveline axis simultaneously to a third axis with another clutch. If the second and third axes cannot turn at the same velocity, these DoFs are in conflict.
Locking too few clutches simultaneously. This error does not overconstrain DoFs or put them in conflict. However, it puts a transmission into a neutral state where it cannot transmit any torque or motion.
For information about adjusting simulation for clutches, see Optimize Simulation of Clutches and Transmissions with Gear Ratios and Clutch Schedules.