Clutch control using dither

摘要

During state transitions, a clutch actuator position command includes an oscillating component called a dither. This dithering helps avoid jumps in the actuator position due to friction when the commanded position is changed gradually. Also, dither during a transition from fully released to slipping causes the natural frequency of the system to change gradually rather than abruptly. This permits use of another slipping clutch for active damping based on a measured oscillation.

主权项

1. A transmission comprising:
an input; an output; a first intermediate shaft; a second intermediate shaft; a first clutch configured to selectively couple the input to the first intermediate shaft; a second clutch configured to selectively couple the input to the second intermediate shaft; a first coupler configured to selectively establish a power flow path between the first intermediate shaft and the output; a second coupler configured to selectively establish a power flow path between the second intermediate shaft and the output, wherein the transmission has a first natural frequency when the first coupler is engaged and the second coupler is disengaged; and a controller programmed to command an oscillating actuator position of the second clutch with a dithering frequency to dampen resonance at the first natural frequency, wherein a ratio of the dithering frequency to the natural frequency is at least 2.5.