A control device for a clutch, which is provided between an operation machine and a drive shaft of an engine, controls an operation of a valve member for opening and closing an oil supply port through which an oil reservoir chamber and a torque transmission chamber communicate. The control device refers to a desired rotation speed of a rotating body of the operation machine and to an acquired rotation speed of the rotating body of the operation machine, calculates a proportional term manipulated variable based on a deviation between an angular acceleration of the rotating body and a desired angular acceleration, and controls the operation of the valve member on the basis of this calculated proportional term manipulated variable.

A control device for a dutch, which is provided between an operating machine and a drive shaft of an engine, controls the operation of a valve member for opening and closing an oil supply hole through which an oil reservoir chamber and a torque transmission chamber communicate. The control device refers to a target rotational speed of a rotational solid of the operating machine and to the acquired rotational speed of the rotational solid of the operating machine, calculates a proportional manipulated variable based on the deviation between the angular acceleration of the rotational solid and a target angular acceleration, and controls the operation of the valve member on the basis of this calculated proportional manipulated variable.

In order to reduce torsional vibrations in a drive including a torque converter with a turbine and impeller, clutch slip speed of the drive is adjusted by manipulation of clutch pressure. This may be done in either closed loop mode or open loop mode by setting the clutch pressure to a predetermined value or continuously adjusting clutch pressure. Pressure is adjusted to produce a positively sloped function of sensed total torque of the clutch and turbine over the clutch slip speed. This produces extended service life of the drive train components, greater efficiency of the torque converter, and smoother operation of the drive.