Openable and closable member control apparatus

1. An openable and closable member control apparatus comprising:

a drive mechanism that includes an electric motor, which serves as a drive source to open and close an openable and closable member installed to a door of a vehicle; and

a control device that is configured to control the drive mechanism, wherein:

the control device is configured to execute a determination operation, which determines whether a captured foreign object, which is captured between the openable and closable member and a corresponding neighboring member of the door located in vicinity of the openable and closable member, is present based on a change in an operational state of the drive mechanism;

the control device is configured to execute an interrupting process that interrupts a current operation of the drive mechanism in response to determining that the captured foreign object is present at the determination operation;

the control device is configured to disable execution of the determination operation, which determines whether the captured foreign object is present, in a mask period that is a time period from a time point of starting rotation of the electric motor to a time point, at which a rotational speed of the electric motor reaches a stable state; and

the control device is configured to change a length of the mask period based on an operational load of the electric motor.

2. The openable and closable member control apparatus according to claim 1 , wherein the control device is configured to determine the operational load of the electric motor based on a rotational speed of the electric motor.

3. The openable and closable member control apparatus according to claim 1 , wherein the control device is configured to change the length of the mask period in response to determining that the operational load of the electric motor is larger than a predetermined operational load.

4. The openable and closable member control apparatus according to claim 1 , wherein:

the mask period is divided into:

a first mask period that is from the time point of starting the rotation of the electric motor to a relay point; and

a second mask period that is from the relay point to a time point that is equal to or around the time point, at which the rotational speed of the electric motor reaches the stable state;

the first mask period is a fixed value; and

the second mask period is a variable value that is corrected through feedback of a state of the operational load of the electric motor in the first mask period.

5. The openable and closable member control apparatus according to claim 4 , wherein:

the control device is configured to count a pulse edge number, which corresponds to the rotation of the electric motor, and the control device is configured to monitor an elapsed time period with a timer from the time point of starting the rotation of the electric motor;

a time period, which is from the time point of starting the rotation of the electric motor to a time point of counting a first pulse edge number by the control device, is set as the first mask period, while the first pulse edge number is a predetermined pulse edge number that is specific to the electric motor;

in a case where a time period from the time point of starting the rotation of the electric motor to an end of the first mask period does not exceed a predetermined time period, a time period, which is from the relay point to a time point of counting a second pulse edge number by the control device, is set as the second mask period, while the second pulse edge number is another predetermined pulse edge number that is specific to the electric motor; and

in a case where the time period from the time point of starting the rotation of the electric motor to the end of the first mask period exceeds the predetermined time period, a time period, which is from the relay point to a time point of counting a third pulse edge number by the control device, is set as the second mask period, while the third pulse edge number is obtained by adding a pulse edge number, which is computed as a time period correction value, to the second pulse edge number.

6. The openable and closable member control apparatus according to claim 5 , wherein the time period correction value is a value obtained by computing a pulse edge number that corresponds to a difference between:

an actual measured time period from the time point of starting the rotation of the electric motor to the time point of counting the first pulse edge number; and

the predetermined time period.

7. The openable and closable member control apparatus according to claim 1 , wherein:

the drive mechanism includes a rotation sensing device that senses the rotation of the electric motor and outputs a pulse signal, which is synchronous with the rotation of the electric motor;

the control device includes:

a controller that controls the drive mechanism; and

a timer that measures time;

the controller is configured to begin counting of a pulse edge number of the pulse signal in response to starting of the rotation of the electric motor;

the controller determines whether an elapsed time period, which is measured with the timer and is from the time point of starting the rotation of the electric motor to a time point of counting the first pulse edge number, is equal to or less than a predetermined time period in response to determining that the pulse edge number counted by the controller reaches a first pulse edge number in the mask period;

the controller ends the mask period and enables the execution of the determination operation at a time point, at which the pulse edge number counted by the controller reaches a second pulse edge number that is larger than the first pulse edge number in response to determining that the elapsed time period, which is measured with the timer and is from the time point of starting the rotation of the electric motor to the time point of counting the first pulse edge number, is equal to or less than the predetermined time period; and

the controller ends the mask period and enables the execution of the determination operation at a time point, at which the pulse edge number counted by the controller reaches a third pulse edge number that is larger than the second pulse edge number in response to determining that the elapsed time period, which is measured with the timer and is from the time point of starting the rotation of the electric motor to the time point of counting the first pulse edge number, is longer than the predetermined time period.

8. The openable and closable member control apparatus according to claim 7 , wherein the controller increases the third pulse edge number in response to an increase in a difference between:

the elapsed time period, which is measured with the timer and is from the time point of starting the rotation of the electric motor to the time point of counting the first pulse edge number; and

the predetermined time period.

9. The openable and closable member control apparatus according to claim 1 , wherein:

the drive mechanism includes a rotation sensing device that detects a rotation of the electric motor;

the control device is configured to determine whether the operational load of the electric motor is larger than a predetermined value based on an output of the rotation sensing device during the mask period; and

the control device is configured to lengthen the mask period by delaying an end of the mask period in response to determining that the operational load of the electric motor is larger than the predetermined value.