Systems, methods, and devices for control of actuators are provided. In aspects, the systems, methods, and devices provided herein enable the generation of sharp cutoff haptic effects of both limited and extended duration. The systems, methods, and devices use open loop braking signals to generate the sharp cutoff haptic effects. The braking signals are determined based on predictions of system response made according to driving signals used to cause the haptic effects in the actuators. Numerous other aspects are provided.

Systems, methods, and devices for control of actuators are provided. In aspects, the systems, methods, and devices provided herein enable the generation of sharp cutoff haptic effects of both limited and extended duration. The systems, methods, and devices use open loop braking signals to generate the sharp cutoff haptic effects. The braking signals are determined based on predictions of system response made according to driving signals used to cause the haptic effects in the actuators. Numerous other aspects are provided.

A method of controlling an all-wheel-drive system connect event including providing a power transmission apparatus having a clutch, a propeller shaft, and a rear drive unit with a clutch pack assembly. The rear drive unit clutch pack is actuated by creating a model of the propeller shaft rotational speed, adapting the model parameters to compensate for temperature and vehicle wheel speed, storing the model, adapting the model utilizing information collected during a previous all-wheel-drive system connect event, and developing a set point for the clutch driving element utilizing the model and a multi-loop control architecture. The power transmission apparatus clutch is then engaged.

A method of controlling an all-wheel-drive system connect event including providing a power transmission apparatus having a clutch, a propeller shaft, and a rear drive unit with a clutch pack assembly. The rear drive unit clutch pack is actuated by creating a model of the propeller shaft rotational speed, adapting the model parameters to compensate for temperature and vehicle wheel speed, storing the model, adapting the model utilizing information collected during a previous all-wheel-drive system connect event, and developing a set point for the clutch driving element utilizing the model and a multi-loop control architecture. The power transmission apparatus clutch is then engaged.

During the inertia phase of a shift, the oncoming clutch is controlled to alleviate shift quality degradation due variability of clutch friction coefficient. The friction coefficient sometimes increases as the slip speed nears zero. The commanded clutch pressure is a sum of an open loop term and a closed loop term. The open loop term decreases as the clutch slip decreases. Thus, when the friction coefficient increases at the end of the inertia phase, the clutch torque remains nearly constant. When the friction coefficient does not increase at the end of the inertia phase, the closed loop term responds to the resulting decreasing rate of slip speed reduction.

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.