The present disclosure relates to a method for defining a clutch slipping point position (X.sub.sp) of a clutch in a gearbox comprising an input shaft arranged to be braked by a braking means. The method includes determining if the clutch is dragging when the clutch is fully disengaged. The method includes when it is determined that the clutch is dragging, applying the braking means with a predetermined brake torque (T.sub.b) and so that the input shaft is not rotating; and thereafter: moving the clutch from the fully disengaged position towards an engaged position; determining when the input shaft starts to rotate with a predetermined rotation value indicative of a rotational speed of the input shaft; registering a clutch position (X.sub.b) in which the clutch is positioned when the predetermined rotation value is reached; using a clutch transfer characteristics of the clutch, T.sub.b, and X.sub.b to define the clutch slipping point position (X.sub.sp).

A method for determining reference values of a sensor corresponding to a disengaged operating condition or to an engaged operating condition of a hydraulically actuatable, form-locking shift element (A, F), where at least one operating parameter of the form-locking shift element (A, F) is detected with the sensor during a disengagement and during an engagement of the form-locking shift element (A, F). The method may include subdividing an operating range of the shift form-locking element (A, F) into temperature and pressure classes. The method may further include determining a deviation between a current reference value for a temperature and pressure class of the temperature and pressure classes and an adapted reference value previously determined for the temperature and pressure class. Additionally, the method may include increasing or decreasing the adapted reference value by a predefined increment based on the deviation.

Methods for automated calibration and adaption of a gearshift controller (39) are disclosed. In one aspect, the method automates calibration a gearshift controller (39) for controlling a sequence of gearshifts in either a stepped automatic transmission equipped with at least one speed sensor mounted on a dynamometer (42) or an automotive vehicle mounted on a dynamometer (42), where the dynamometer (42) is electronically controlled by a dynamometer controller (43). Each gearshift in the sequence includes a first phase, a second phase, . . . and an N.sup.th phase. The gearshift controller (39) includes (initial values of) a first phase control parameters set, a second phase control parameters set, . . . and an N.sup.th phase control parameters set for each gearshift in the sequence that are updated using a first phase learning controller, a second phase learning controller, . . . and an N*11 phase learning controller respectively.

A transmission combination includes a hydrostatic transmission and a mechanical transmission having a clutch and a control device for calibrating a grinding point of the clutch. A traction drive includes the transmission combination. A method includes calibrating the clutch.

Methods for automated calibration and adaption of a gearshift controller (39) are disclosed. In one aspect, the method automates calibration a gearshift controller (39) for controlling a sequence of gearshifts in either a stepped automatic transmission equipped with at least one speed sensor mounted on a dynamometer (42) or an automotive vehicle mounted on a dynamometer (42), where the dynamometer (42) is electronically controlled by a dynamometer controller (43). Each gearshift in the sequence includes a first phase, a second phase, . . . and an N.sup.th phase. The gearshift controller (39) includes (initial values of) a first phase control parameters set, a second phase control parameters set, . . . and an N.sup.th phase control parameters set for each gearshift in the sequence that are updated using a first phase learning controller, a second phase learning controller, . . . and an N*11 phase learning controller respectively.

A calibration method for a slip control arrangement of a driveline including a continuously variable transmission is described herein. The driveline includes a clutch that is so controlled as to slip when a torque higher than the usable torque attempts to pass through. Accordingly, the clutch prevents the prime mover from stalling. A calibration method to link a valve command value and a torque allowed to pass through the clutch includes preventing the vehicle from moving and increasing the pressure applied in the clutch while noting the torque % value developed by the prime mover.

The present disclosure relates to a method for defining a clutch slipping point position (X.sub.sp) of a clutch in a gearbox comprising an input shaft arranged to be braked by a braking means. The method includes determining if the clutch is dragging when the clutch is fully disengaged. The method includes when it is determined that the clutch is dragging, applying the braking means with a predetermined brake torque (T.sub.b) and so that the input shaft is not rotating; and thereafter: moving the clutch from the fully disengaged position towards an engaged position; determining when the input shaft starts to rotate with a predetermined rotation value indicative of a rotational speed of the input shaft; registering a clutch position (X.sub.b) in which the clutch is positioned when the predetermined rotation value is reached; using a clutch transfer characteristics of the clutch, T.sub.b, and X.sub.b to define the clutch slipping point position (X.sub.sp).

A calibration method for a slip control arrangement of a driveline including a continuously variable transmission is described herein. The driveline includes a clutch that is so controlled as to slip when a torque higher than the usable torque attempts to pass through. Accordingly, the clutch prevents the prime mover from stalling. A calibration method to link a valve command value and a torque allowed to pass through the clutch includes preventing the vehicle from moving and increasing the pressure applied in the clutch while noting the torque % value developed by the prime mover.

A method of controlling a dual clutch transmission, may include releasing a pressure of a non-driveshaft clutch and engaging a gear of a non-driveshaft; applying a first pressure to the non-driveshaft clutch and disengaging the gear of the non-driveshaft; determining a drag torque on the basis of a first rotation speed change rate of the non-driveshaft; releasing the first pressure and engaging the gear of the non-driveshaft; applying a second pressure to the non-driveshaft clutch and disengaging the gear of the non-driveshaft; determining a touch point torque on the basis of a second rotation speed change rate of the non-driveshaft; and adjusting a touch point of the non-driveshaft clutch on the basis of a net torque which is a difference between the touch point torque and the drag torque.

A calibration method for a slip control arrangement of a driveline including a continuously variable transmission is described herein. The driveline includes a clutch that is so controlled as to slip when a torque higher than the usable torque attempts to pass through. Accordingly, the clutch prevents the prime mover from stalling. A calibration method to link a valve command value and a torque allowed to pass through the clutch includes preventing the vehicle from moving and increasing the pressure applied in the clutch while noting the torque % value developed by the prime mover.