Electricity: motive power systems – Automatic and/or with time-delay means
Reexamination Certificate
2000-07-27
2002-06-11
Fletcher, Marlon T. (Department: 2816)
Electricity: motive power systems
Automatic and/or with time-delay means
C318S432000, C318S453000, C318S466000, C318S264000, C318S286000
Reexamination Certificate
active
06404157
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to techniques for reducing power consumption in a motor driven system, and more specifically to circuitry for generating a system wake up signal as a function of manual motor actuation in a motor driven system having a power conserving sleep function.
BACKGROUND OF THE INVENTION
Passenger vehicles are typically equipped with a rear vehicle compartment for storing a spare tire and/or for transporting items such as groceries, luggage, tools, and the like. Some such vehicles, commonly known as sport utility vehicles, include a hatch or lift gate for accessing such a compartment. Passenger vans, on the other hand, typically include one or more sliding doors for accessing a rear passenger and/or storage compartment.
In vehicles of the foregoing type, control systems are known and currently available for automatically opening and/or closing lift gates and sliding doors. So-called “power lift gate” and “power sliding door” systems may be physically or remotely actuated whereby a dedicated control circuit is operable to control one or electrically driven motors to drive the lift gate or door to either an open or closed position. Referring to
FIG. 1
, an example of one known motor control system
10
of the foregoing type is shown. System
10
includes a control circuit
12
, such as a known microprocessor-based control unit, electrically connected to a motor actuation circuit
14
via a number, N, of signal paths
16
, wherein N may be any positive integer. The motor actuation circuit
14
is of known construction and is electrically connected to an electrical motor
18
via a number, M, of signal paths
20
, wherein M may be any positive integer. Motor
18
is typically a direct drive motor and includes a motor drive shaft L that is connected to an automotive door or lift gate
22
either directly or via mechanical linkage. A motor position determining circuit
24
of known construction is typically electrically connected to motor
18
, or alternatively to motor actuator circuit
14
, via a number, J, of signal paths
26
, wherein J may be any positive integer. The motor position detection circuit is electrically connected to control circuit
12
via a number, K, of signal paths
28
, wherein K may be any integer.
In operation, control circuit is operable to produce one or more motor control signals on signal paths
16
, wherein motor actuation circuit
14
is responsive to the one or more motor control signals to produce one or more motor drive signals on signal paths
20
. The motor
18
is, in turn, responsive to the one or more motor drive signals to correspondingly rotate its drive shaft L and thereby automatically drive movement of the door or lift gate
22
. The control circuit
12
is typically operable to track the position of the door or lift gate
22
via one or more signals produced by the motor position circuit
24
.
Currently, known power lift gate and power sliding door systems of the foregoing type operate in a stand-by mode of operation wherein electrical power is constantly applied to the system. This arrangement ensures that such systems are readily operable and that the control circuit may therefore instantaneously control the present gate/door position. However, such systems have a drawback in that electrical power is needlessly consumed thereby. It would accordingly be advantageous in such systems to provide for “sleep” and “wake-up” modes of operation, wherein the system enters a low power consumption sleep mode after expiration of some predefined time period following gate/door actuation, and wherein the system wakes up to a full power operational mode upon manual gate/door actuation. Presently, however, no such systems are known that include the ability to wake up from sleep mode in response to manual gate/door actuation.
What is therefore needed is an improved power door/lift gate system operable in sleep and wake-up operational modes, wherein such a system includes a reliable mechanism for waking up from sleep mode operation in response to manual door/lift gate movement.
SUMMARY OF THE INVENTION
The foregoing shortcomings of the prior art are addressed by the present invention. In accordance with one aspect of the present invention, circuitry for producing a wakeup signal based on back electromotive force (EMF) of a motor comprises a motor having a drive shaft and at least one input for receiving a motor drive signal, wherein the motor is responsive to the motor drive signal to rotate the drive shaft, wherein the motor produces a back EMF signal at the at least one input in the absence of the motor drive signal and in response to rotational movement of the drive shaft, and a wakeup circuit having an input connected to the at least one input of the motor and an output, wherein the wakeup circuit is responsive to the back EMF signal at the input thereof to produce a wakeup signal at the output thereof.
In accordance with another aspect of the present invention, a method for producing a wakeup signal in a motor control system based on back electromotive force (EMF) of an electrically driven motor comprises the steps of monitoring an electrical input of a motor having a drive shaft, wherein the motor is responsive to a motor drive signal to rotate the drive shaft, and wherein the motor produces a back EMF signal in response to movement of the drive shaft in the absence of the motor drive signal, and producing a wakeup signal is response to detection of the back EMF signal.
One object of the present invention is to provide an electrical circuit for producing a wakeup signal as a function of back electromotive force (EMF) of a motor.
Another object of the present invention is to utilize such a circuit in an electrical motor control system operable to drive a power sliding door or power lift gate assembly in an automotive environment.
Another object of the present invention is to utilize such a circuit in such an electrical motor control system that is operable in a reduced-function, reduced-power consumption sleep mode of operation and in a full-function, full-power consumption wakeup mode of operation, for waking up the system from sleep mode in response to manual actuation of the door or lift gate.
These and other objects of the present invention will become more apparent from the following description of the preferred embodiments.
REFERENCES:
patent: 4529920 (1985-07-01), Yoshida et al.
patent: 5793174 (1998-08-01), Kovach et al.
patent: 5869940 (1999-02-01), Prsadayan
patent: 6081091 (2000-06-01), Mitchell et al.
patent: 6184645 (2001-02-01), Brito et al.
Fletcher Marlon T.
Funke Jimmy L.
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