Assuming 1-2 upshift case, uon is set to Tc2, and uof f is  set to Tc1 Since two intermediate shafts for clutch 1 and 2 are coupled with each other, TJ   is bounded as some value   with

respect to the inertia and the shaft   acceleration。

Therefore, uon and uof f are constrained as a nondecreasing function and a nonincreasing function, respectively。 Also, this makes a system to be constrained into the admissible set A。

In this formulation, the control input u(t) is bounded   and

Fig。 6。    Block diagram of the engine speed/torque   control

time, it is assumed that the engine speed changes linearly with time。 In 1-2 upshift case, the target speed is defined  as:

∂ ωc1a(t) 。 it2 。

the admissible set A is defined to represent the constrained state-space for gear shifting management system。 The convex

ωc2d (t)= ωc2a(t)+ ∂t

it1

(ti − tc) (22)

combination of two control inputs can be thought of as weighted average transmission torque to a vehicle during gearshift。

In other words, the constraints of the off-going clutch  can

be applied in compensation for the oncoming clutch, and vice

where,  the  time  derivative  of  the  ωc1a(t)  is  numerically

obtained from the measurement signal in t ∈ [tc, ti] to avoid

noise problem。 Accordingly, the engine torque controller is simply designed as

¸ ti

versa。 Therefore, the transmitted torque quantity on the shaft remains within a certain amount of torque。 These are mainly

Te = −KPe (ωc2(t) − ωc2d (t)) −

KIe (ωc2(τ) − ωc2d (τ)) dt

from the unique feature of dual clutch transmissions that have two clutches as multiple inputs。 A gearshift  operation is simultaneously performed with the engagement of the on- coming clutch and the disengagement of the off-going clutch。 Thus, this strategy aims at maximizing such an advantage of DCTs in conjunction with the control formulation。 Fig。 5 shows the schematic of the control concept of the proposed strategy。

C。 Engine Control

During gearshift process, there is abrupt change of vehicle driveline speed so that the drive shaft torque is also dropped unexpectedly (i。e。 torque phase)。 This is mainly due to interrupting transferred torque in a moment。 When the gear shifting is completed, the drive shaft torque is recovered to its desired value corresponding to the gear ratio of newly engaged speed (i。e。 inertia phase)。 Generally, some overshoot can occur because of  variation  in  transferring  torque  in the inertia phase。 It may lead to a vehicle jerk, which is recognized as drivers discomfort。

To solve this problem, engine torque reduction must be considered incorporating with gear shifting control consid- ered in the preceding subsection。 For example, when the clutch is controlled in order to achieve an upshift process, the engine torque controller defines the target engine speed at which the clutch engagement is completed。 If the target engine speed is too low compared with the nominal value, it is possible that the engine is stalled。 On the other hand, too high target engine speed may deteriorate the shift quality。 Therefore, the target engine speed for engine torque reduc- tion must be chosen appropriately。

The target engine speed can be determined by two clutch speed measurements and the desired gear shifting duration。 Since  the  gear  shifting  is  performed  in  a  short  period of