Headrest control apparatus and method

• US 20080067841A1
• Filed: 08/23/2007
• Published: 03/20/2008
• Est. Priority Date: 08/23/2006
• Status: Active Grant

• Current Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Aisin Seiki Co., Ltd. (Aisin Corp.), Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Aiyama, Takaya, Iyoda, Motomi, Matsubayashi, Kiyoka, Okawa, Tatsuhiro
• Granted Patent: US 7,614,690 B2
• Time in Patent Office: Days
• US Class Current: 297/216.12
• CPC Class Codes: B60N 2/0276 reaction to emergency situations, e.g. crash
• CPC Class Codes: B60N 2/888 with arrangements for protecting against abnormal g-forces, e.g. by displacement of the head-rest
• CPC Class Codes: B60R 2021/0011 Rear collision or recoiling bounce after frontal collision
• CPC Class Codes: B60R 2021/0048 Head
• CPC Class Codes: B60R 2021/01252 Devices other than bags
• CPC Class Codes: B60R 21/0134 responsive to imminent contact with an obstacle , e.g. using radar systems
• CPC Class Codes: G01S 2013/93272 in the back of the vehicles

Abstract

A headrest control apparatus has a rear radar sensor, a PCS-ECU, a headrest drive mechanism that supports a headrest and drives the headrest relative to the vehicle in its longitudinal direction, a motor, a capacitance sensor, and a headrest control portion that controls the motor. The headrest control portion executes a forward drive control in which the headrest starts to be driven forward in response to a start-up signal from the PCS-ECU and the motor is stopped in response to the positional relation between the occupant'"'"'s head and the headrest reaching a predetermined positional relation. After the forward drive control, the headrest control portion executes a hold control in which the motor is held in a stopped state for a predetermined hold time. After the hold control, the headrest control portion executes a backward drive control in which the headrest is driven backward.

Claims

1. A headrest control apparatus, comprising:

a rear state detection device that detects a following vehicle;

a collision determination device that determines, based on the result of the detection by the rear state detection device, whether the possibility of collision between the following vehicle and a subject vehicle is high and outputs a start-up signal if the possibility of collision is high;

a headrest drive mechanism that supports a headrest and drives the headrest relative to the subject vehicle in the longitudinal direction of the subject vehicle;

a motor that produces a force for driving the headrest in the longitudinal direction;

a head position detection device that detects the position of the bead of an occupant relative to the headrest; and

a headrest control portion that controls the longitudinal position of the headrest by activating the motor in accordance with the output of the collision determination device, wherein

the headrest control portion executes a forward drive control that starts to drive the headrest forward by activating the motor in response to the start-up signal from the collision determination device and then finishes the forward drive of the headrest by stopping the motor when detecting, from the signals from the head position detection device, that the positional relation between the head of the occupant and the headrest has reached a predetermined positional relation,

the headrest control portion, after the forward drive control, executes a hold control that holds the motor in a stopped state for a predetermined hold time, and

the headrest control portion, after the hold control, executes a backward drive control that drives the headrest backward by activating the motor to rotate in a reverse direction.

2. The headrest control apparatus according to claim 1, wherein the headrest control portion stops the motor when the continuous operation time of the motor exceeds a first reference time during the forward drive control.

3. The headrest control apparatus according to claim 2, wherein the headrest control portion sets the first reference time in accordance with the speed at which the headrest is moved forward.

4. The headrest control apparatus according to claim 3, wherein the higher the speed at which the headrest is moved forward, the headrest control portion shortens the first reference time period.

5. The headrest control apparatus according to claim 1, wherein the headrest control portion stops the motor when the continuous operation time of the motor exceeds a second reference time during the backward drive control.

6. The headrest control apparatus according to claim. 5, wherein the headrest control portion sets the second reference time to a time that allows the headrest to return to a retracted position of the headrest.

7. The headrest control apparatus according to claim 1, wherein the headrest control portion continues the hold control by extending the predetermined hold time when receiving the start-up signal again from the collision determination device during the hold control.

8. The headrest control apparatus according to claim 7, wherein when receiving the start-up signal again from the collision determination device during the hold control, the headrest control portion resets the count of the present hold time and starts counting a new hold time.

9. The headrest control apparatus according to claim 7, wherein the headrest control portion continues the hold control until the predetermined hold time passes from when receiving the start-up signal again.

10. The headrest control apparatus according to claim 1, wherein when receiving the start-up signal again from the collision determination device during the backward drive control, the headrest control portion discontinues the backward drive control and starts the forward drive control.

11. A method for controlling an active headrest including a headrest drive mechanism that supports a headrest and drives the headrest relative to a subject vehicle in the longitudinal direction of the subject vehicle and a motor that produces a force for driving the headrest in the longitudinal direction, the method comprising:

detecting a following vehicle;

outputting a start-up signal if the possibility of collision between the following vehicle and the subject vehicle is determined to be high based on the result of the following vehicle detection;

activating, in response to the start-up signal, the motor to drive the headrest forward until the positional relation between the head of an occupant and the headrest reaches a predetermined positional relation;

holding, after driving the headrest forward, the motor in a stopped state for a predetermined hold time; and

activating, after holding the motor in a stopped state for the predetermined hold time, the motor to rotate in a reverse direction to drive the headrest backward.

12. The method according to claim 11, wherein when the start-up signal is output again while the motor is held in the stopped state, the predetermined hold time is extended so that the motor continues to be held in the stopped state.

13. The method according to claim 12, wherein when the start-up signal is output again while the motor is held in the stopped state, the count of the present hold time is reset and a new hold time starts to be counted.

14. The method according to claim 12, wherein when the start-up signal is output again, the motor continues to be held in a stopped state until the predetermined hold time passed form when receiving the start-up signal again.

15. The method according to claim 11, wherein when the start-up signal is output again while the headrest is being driven backward, the backward drive control is discontinued and the forward drive control is then started.