Abstract A dry clutch induces judder phenomenon which is caused by variations in the vehicle load condition and frictional material properties. Such a problem may lead to the stick-slip limit cycle that results in undesired longitudinal vibrations of vehicles. To solve this problem, a vibration suppression control is proposed. The amplitude of vibrations is detected by the signal conditioning from the measurements with the transmission input shaft speed and the wheel speed sensors. Based upon this, a perturbation torque is applied additionally on the nominal launch controller to make the drive shaft oscillation vanish. It can be achieved by the control design without any extra hardware cost. Finally, experimental results confirm the effectiveness of the proposed mechanism. Introduction A dry clutch has been widely used in automotive transmissions such as Automated Manual Transmissions (AMT) and Dual Clutch Transmissions (DCT) due to higher torque transmission efficiency [1]. There are some difficulties in clutch control to satisfy the control performance corresponding to a torque converter-based automatic transmission. In the case of the wet clutch system, it is advantageous to vibration suppressions as well as lubrication and cooling effect of the disk. However, the higher pressure needs to be applied for having higher level of the torque capacity. On the other hands, a dry friction clutch could have higher efficiency , but abrupt change of the controlled torque may lead to the undesired acceleration variations. It is originated from the mechanical connection between the engine flywheel and the clutch disk without damping. In control perspective, one of the critical problems is judder phenomenon particularly for a dry-clutch system. Judder is a friction induced self-excitation when the clutch makes contact with. This excitation on the clutch disk may lead to the driveline oscillations so that it should be suppressed for production vehicles [ 2, 3].Judder means driveline oscillations generated from applied force on a frictional clutch disk. This undesirable behavior mainly comes from the following causes: 1. Dynamic variations on a disk friction coefficient 2. Clutch facing material quality 3. Self-excitation by load changes during the slip phase 4. Eccentricity and misalignment of the drive shaft Also, judder possibly occurs under the condition that the driving conditions are varies with external disturbances. Such a disturbance along the longitudinal direction induces driveline oscillations, which makes drivers and passengers discomfort. Accordingly, drive-ability will be getting worse. Therefore, it should be effectively suppressed by hardware design improvement. It would be helpful that the use of the advanced materials and increasing stiffness of the driveshaft are fundamental ways to solve this problem. However, it is quite difficult to be achieved due to the fact that hardware modification is expensive and time consuming for automotive manufacturers. When the hardware cannot easily be modified due to time limitation in the development process and some reasons mentioned above, the control approach needs to be considered as an alternative to solve this problem. Since this is achieved only by software development, it is cost effective for production vehicles. Some clutch manufacturers make an effort to develop a control approach for judder suppression [4]. However, the detailed method has not been discussed. In this paper, a clutch controller is proposed to suppress input shaft oscillations caused by self-excited vibrations. The proposed controller is designed as an add-on type and easily implemented to predefined launch control that has been in operation for a nominal launch control. Our clutch controller for vibration suppression is particularly for natural frequency with a range from 6 to 8 Hz. Note that the higher frequency more than 10Hz is not taken into account because the gi