transitions between the speed ranges. If a smooth
clutch-to-clutch shift were possible, this expensive
mechanical component can be eliminated and
the overall kinematic arrangement can be significantly
simplified. This step offers economic
advantages but presents a challenging control
problem. Two primary objectives in shift control
are smooth transients and fast shift completion.
The shift smoothness is related to the vehicle
acceleration, which is proportional to the torque
of the drive axle shaft. The fast shift completion is
related to the clutch energy dissipation and components'
longevity. Thus, this paper presents
methods for effecting a smooth shift within a
short time period.
Meanwhile, the sensors currently used for
measuring the shaft torque are too expensive to be
used on production vehicles for control purpose,
but magnetic pick-up speed sensors can be widely
applied for speed checking, shift decision, engine
control and anti-skid braking, etc. Thus, indirect
means for regulating shift torque using speed
information is required.
Recalling a long history and wide popularity of
automatic transmission, there are plenty of experimental
results on the shift characteristics and shift