US 4,730,152 AGranted

Vehicle power antenna control with drive stress limiting

AssigneeGeneral Motors Corporation

InventorsJeff A. Foust, Donald E. Graham, Richard E. Wainwright, Gary R. Denton

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Abstract

A power antenna control for a motor vehicle comprises a Hall effect device responsive to motor armature rotation to generate pulses for equal predetermined increments of antenna travel. These pulses are applied to both position and stall counters. In extension, the antenna drive is stopped when the position counter reaches a number corresponding to a predetermined extended position, which may be full extension or some lesser extension. In retraction, the stall counter is used with a clock to indicate stall which, when detected, causes the antenna drive to be stopped. Automatic current limiting for drive torque limitation during stall is activated only when the position counter indicates a limited position range near full retraction. Further during retraction, if the antenna is stopped within a small position range of full rectraction, it is reset to a count indicating full retraction. The system eliminates the need for hard stall sensing reaction switches and thus reduces antenna drive cable fatigue.

Claims6

Dependent claims

A power antenna control for a motor vehicle having antenna drive means effective to extend and retract the antenna relative to the vehicle, the antenna drive means including a DC motor having an armature, the control comprising, in combination:

pulse signal means responsive to movement of the antenna drive means to generate pulses for equal predetermined increments of antenna travel;
a first counter responsive to the pulse signal means while the antenna is extending to change its count in a first direction and while the antenna is retracting to change its count in the opposite direction to thereby maintain a count indicative of antenna position;
a second counter responsive to the pulse signal to count in a first direction;
means responsive to the first counter during antenna extension to deactivate the antenna drive means when the count of the first counter indicates a predetermined extended antenna position;
means effective to periodically monitor the count of the second counter and reset the count to an initial value and, when said monitored count is less than a predetermined count indicating motor stall, to generate a stall signal;
means responsive to the stall signal during antenna retraction to deactivate the antenna drive means and, if the count of the first counter is within a predetermined count of full retraction, to reset the count of the first counter to the count indicating full retraction;
means activatable to limit the current in the motor armature to a predetermined maximum value;
and
means responsive to the first counter to activate the current limiting means only when the count of the first counter is within a range corresponding to a predetermined range of antenna position close to full retraction.

6 more elements

Dependencies are inferred from the claim text.