The disclosure of Japanese Patent Application No. JP2010-290483 filed on Dec. 27, 2010 including the specification, drawings, claims and abstract is incorporated herein by reference in its entirety.
1. Field of the Invention
The present invention relates to a vehicle mirror control method and device for controlling a motor for electrically displacing a mirror angle of a vehicle mirror, which are arranged so that when the mirror angle is automatically displaced toward a target position (target angle), if the movement is mechanically locked before reaching the target position, power supply to the motor can promptly be halted and even in the case of a low temperature and a low voltage where the operating speed is slow, the vehicle mirror can reach the target position.
2. Description of the Related Art
As a vehicle mirror whose mirror angle is electrically adjusted (hereinafter referred to as “electric mirror”), there is one arranged to set a mirror angle or a mirror angle displacement amount and automatically displace the mirror angle toward the corresponding target position. For example, in the case of an electric mirror called “memory mirror”, a mirror angle (including a vertical angle and a horizontal angle) manually adjusted by a driver is detected and stored in a memory, and when returning the mirror angle to its original mirror angle after being changed to another angle, the mirror angle stored in the memory is read and set as a target value via a one-touch operation of, e.g., a switch to automatically adjust the mirror angle to the read target value (memory operation). Meanwhile, in the case of an electric mirror called “reverse interlock mirror”, a mirror surface of a vehicle outer mirror is rotated downward by the amount of a predetermined angle in relation to gearshift operation means of the vehicle being put into a reverse position so that a driver can view an area around the rear wheel when driving the vehicle back (e.g., making the vehicle enter a parking space), and subsequently, the mirror surface is rotated upward by the amount of the predetermined angle to return to its original mirror angle in relation to the gear shift operation means being switched from the reverse position to another gear position (reverse interlock operation). An example of the memory mirror is disclosed in Japanese Patent Laid-Open No. S59-156842. An example of the reverse interlock mirror is disclosed in Japanese Patent Laid-Open No. H01-314640.
A case where a reverse interlock operation is performed when a mirror angle can be adjusted within the adjustment range illustrated in
A cause of the case where the difference between a target position and a current position is not decreased in a reverse interlock operation or a memory operation may be a failure of the motor, an abnormality of the position sensor or slippage for any cause. In addition, a motion start delay in the case of a low temperature and a low voltage (for example, a case where the voltage of a 12V battery is lowered to 8V at a temperature of −30° C.) can also be considered as a cause. In other words, as illustrated in
The present invention aims to provide a vehicle mirror control method and a vehicle mirror control device, which solve the aforementioned conventional art problems, and are arranged to when automatically displacing a mirror angle toward a target position, promptly halt power supply to a motor when the movement is mechanically locked before the mirror angle reaching the target position, and make the mirror angle reach the target position even in the case of a low temperature and a low voltage where the operating speed is slow.
The present invention provides a vehicle mirror control method for controlling a motor to displace a mirror angle of a vehicle mirror toward a target position while detecting a current position of the mirror angle, the method including: a first time period setting step of setting a first time period as a reference value for monitoring time during which a state where no change in the mirror angle is detected continues from a start of power supply to the motor to displace the mirror angle toward the target position; a second time period setting step of setting a second time period as a reference value for monitoring time during which a state where no decrease in a difference between the target position and the current position is detected continues during the power supply to the motor to displace the mirror angle toward the target position, the second time period being shorter than the first time period; a first halting step of when the time during which a state where no change in the mirror angle is detected continues from a start of power supply to the motor to displace the mirror angle toward the target position exceeds the first time period, halting the power supply to the motor; a second halting step of when a change in the mirror angle is detected before a lapse of the first time period after the start of the power supply to the motor to displace the mirror angle to the target position, continuing the power supply to the motor, and subsequently, when the time during which a state where no decrease in the difference between the target position and the current position is detected continues exceeds the second time period, halting the power supply to the motor; and a third halting step of when none of the first halting step and the second halting step halts the power supply to the motor before the mirror angle reaching the target position, halting the power supply to the motor so as to halt the mirror angle at the target position.
The present invention provides a vehicle mirror control device for controlling a motor to displace a mirror angle of a vehicle mirror toward a target position while detecting a current position of the mirror angle, the control device including: a mirror angle detection unit that detects the mirror angle; a first time period setting unit that sets a first time period as a reference value for monitoring time during which a state where no change in the mirror angle is detected continues from a start of power supply to the motor to displace the mirror angle toward the target position; a second time period setting unit that sets a second time period as a reference value for monitoring time during which a state where no decrease in a difference between the target position and the current position is detected continues during the power supply to the motor to displace the mirror angle toward the target position, the second time period being shorter than the first time period; and a control unit that controls the power supply to the motor to displace the mirror angle toward the target position, wherein the control performed by the control unit includes: first halting control for when the time during which a state where no change in the mirror angle is detected continues from a start of power supply to the motor to displace the mirror angle toward the target position exceeds the first time period, halting the power supply to the motor; second halting control for when a change in the mirror angle is detected before a lapse of the first time period after the start of the power supply to the motor to displace the mirror angle to the target position, continuing the power supply to the motor, and subsequently, when the time during which a state where no decrease in the difference between the target position and the current position is detected continues exceeds the second time period, halting the power supply to the motor; and third halting control for when none of the first halting control and the second halting control halts the power supply to the motor before the mirror angle reaching the target position, halting the power supply to the motor so as to halt the mirror angle at the target position.
As described above, a mirror angle adjustment motor may not start rotating immediately after power supply in the case of a low temperature and a low voltage. However, even in such case, the motor gradually starts rotating, and once the motor starts rotating, the motor continues the rotation unless the power supply is discontinued. Accordingly, setting a first time period to a time period sufficient to detect a change in the mirror angle even at a low temperature and a low voltage can prevent the mirror angle from stopping somewhere on the way without reaching the target position and make the mirror angle reach the target position in the case of a low temperature and a low voltage. If a change is detected before a lapse of the first time period, the set time period is switched from the first time period to a second time period that is shorter than the first time period, and time during which a state where no decrease in the difference between the target position and the current position is detected continues is monitored using the second time period. Consequently, upon occurrence of slippage in the clutch, the power supply to the motor can promptly be halted. Furthermore, where no change in the mirror angle is detected because of a failure or an abnormality of, e.g., the motor or a position sensor, the power supply to the motor is halted after a lapse of the first time period, and thus, the motor can be prevented from being continuously driven.
In the present invention, in the first halting control (the first halting step), a change in the mirror angle can be detected when the change in the mirror angle exceeds a predetermined dead zone, and in the second halting control (the second halting step), a decrease in the difference between the target position and the current position can be detected when the difference between the target position and the current position is decreased beyond a predetermined dead zone. Consequently, a false operation due to noise in position detection can be prevented. Furthermore, the time during which a state where no decrease in the difference between the target position and the current position is detected continues can be measured as, for example, time during which a state where a minimum value of the difference between the target position and the current position is not updated continues.
An embodiment of the present invention will be described below. Here, a case where the present invention is applied to reverse interlock control will be described.
A long-term determination period setting unit (first time period setting unit) 16 sets a long-term determination period (first time period) as a reference value for monitoring time during which a state where no change in the mirror angle is detected continues from the start of power supply to the motor 10 to displace the mirror angle toward the target position by means of reverse interlock control. The long-term determination period is a time period sufficient to detect a change in the mirror angle beyond a dead zone (
A short-term determination period setting unit (second time period setting unit) 18 sets a short-term determination period (second time period) as a reference value for monitoring time during which a state where no decrease in a difference between the target position and the current position is detected continues after a change in the mirror angle in the long-term determination period has been detected. Upon occurrence of slippage, as illustrated in
A control unit 20 performs the following control as control for starting a reverse interlock operation, and thus, displacing the mirror angle toward the target position when the gearshift operation means of the vehicle is put into the reverse position.
Long-term determination is performed when the power supply to the motor 10 to displace the mirror angle to the target position is started. That is, time during which no change in the mirror angle is detected is measured, and when such time exceeds the long-term determination period, the power supply to the motor 10 is halted.
If a change in the mirror angle is detected before a lapse of the long-term determination period after the start of the power supply to the motor 10, the short-term determination is performed in place of the long-term determination. That is, the power supply to the motor 10 continues and time during which a state where no decrease in the difference between the target position and the current position is detected continues is measured, and if such time exceeds the short-term determination period, the power supply to the motor 10 is halted.
If none of the long-term determination and the short-term determination halts the power supply to the motor 10 and the mirror angle reaches the target position, the power supply to the motor 10 is halted at the target position.
As a result of controlling the motor 10 as described above, the following operations are performed.
(a) If, e.g., a failure of the motor 10 or an abnormality of the mirror angle detection unit 12 has occurred from the beginning of the reverse interlock control, the power supply to the motor 10 is halted after a lapse of the long-term determination period.
(b) If slippage occurs in the clutch as a result of the displacement of the mirror angle being mechanically locked before the mirror angle reaching the target position, the power supply to the motor 10 is halted after a lapse of the short-term determination period.
(c) Even at a low temperature and a low voltage, the mirror angle reaches the target position as in the case of a non-low temperature and/or a non-low voltage unless a failure of the motor 10, an abnormality of the mirror angle detection unit 12 or slippage in the clutch Occurs.
Accordingly, if the movement is mechanically locked before the mirror angle reaching the target position, the power supply to the motor 10 can promptly be halted, and even in the case of a low temperature and a low voltage where the operating speed is slow, it can be ensured that the mirror angle reaches the target position, and furthermore, upon occurrence of, e.g., a failure of the motor 10 or an abnormality of the mirror angle detection unit 12, the power supply can also be halted.
When the gearshift operation means is switched from the reverse position into another gear position, the control unit 20 performs control to drive the motor 10 in the opposite direction to return the mirror angle to the position θ1 of the mirror angle immediately before the start of the reverse interlock control, which is stored in the mirror angle storage unit 13.
Upon a change exceeding the prescribed value being detected in the long-term determination period after the start of the reverse interlock operation (“YES” in S7), the long-term determination is ended and the control transitions to short-term determination (S10). In the short-term determination, time during which a state of a difference between the target position and the current position being not decreased beyond the prescribed value (dead zone in
(1) A difference between the target position and the current position is obtained and stored.
(2) A difference between the stored difference and a difference obtained later (amount of change in the difference between the target position and the current position) is obtained (S11).
(3) If the amount of change exceeds the prescribed value (dead zone in
(4) If the amount of change does not exceed the prescribed value (the difference between the target position and the current position is not decreased) (“NO” in S12), the stored difference is not updated.
(5) The above-described operation is repeated for every repetition period of the flow in
(6) Time during which a state of the amount of change not exceeding the prescribed value continues is measured in terms of the number of times determination of “NO” is successively made in step S12 (that is, the number of times where the minimum value is successively not updated) is measured (S13), and when such time exceeds the short-term determination period (for example 5 msec×200 times=1 second) (“YES” in S13), the power supply to the motor 10 is halted (S14). Consequently, upon occurrence of slippage in the clutch, the motor 10 can be stopped in a short time to prevent the slippage from continuing for a long time.
If after detection of a displacement in the long-term determination, approach of the mirror angle to the target position is detected in the short-term determination (“YES” in S12), the power supply to the motor 10 to displace the mirror angle toward the target position is continued, and if the mirror angle reaches the target position (“YES” in S5), the power supply to the motor 10 is halted (S16). Consequently, a driver can drive his/her vehicle back while viewing an area around the rear wheel through the mirror. When the gearshift operation means of the vehicle is returned from the reverse position to another gear position, the mirror angle is returned to its original position stored in step S3.
Although in the above embodiment, the dead zones (
Number | Date | Country | Kind |
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2010-290483 | Dec 2010 | JP | national |