Vehicle Seat

Abstract

Provided is a vehicle seat that detects an alertness level of the driver, urges the driver to be alert, and permits the transition from autonomous driving to manual driving when the driver is alert enough for the manual driving. A vehicle seat configured to be mounted on a vehicle provided with a vehicle control device that can be selectively switched from autonomous driving to manual driving comprises: a seat body configured to support a driver; a seat control unit configured to communicate with the vehicle control device; an alertness level sensor provided on the seat body for detecting an alertness level of the driver; and a rousing unit provided on the seat body for providing a stimulus for urging the driver to be roused, wherein the seat control unit is configured to detect the alertness level of the driver according to a signal from the alertness level sensor upon receiving a start signal that is produced by the vehicle control device when a transition from the autonomous driving to the manual driving is to be initiated, to activate the rousing unit when the alertness level is lower than a first alertness level threshold value, and to permit the vehicle control device to perform the transition from the autonomous driving to the manual driving when the alertness level is equal to or higher than the first alertness level threshold value.

1 . A vehicle seat configured to be mounted on a vehicle provided with a vehicle control device that can be selectively switched from autonomous driving to manual driving, comprising:
 a seat body configured to support a driver;   a seat control unit configured to communicate with the vehicle control device;   an alertness level sensor provided on the seat body for detecting an alertness level of the driver; and   a rousing unit provided on the seat body for providing a stimulus for urging the driver to be roused;   wherein the seat control unit is configured to detect the alertness level of the driver according to a signal from the alertness level sensor upon receiving a start signal that is produced by the vehicle control device when a transition from the autonomous driving to the manual driving is to be initiated, to activate the rousing unit when the alertness level is lower than a first alertness level threshold value, and to permit the vehicle control device to perform the transition from the autonomous driving to the manual driving when the alertness level is equal to or higher than the first alertness level threshold value.   
     
     
         2 . The vehicle seat according to  claim 1 , wherein the seat control unit is configured to prohibit the transition from the autonomous driving to the manual driving by the vehicle control device and to keep the rousing unit activated when the start signal is received as long as the alertness level is lower than the first alertness level threshold value. 
     
     
         3 . The vehicle seat according to  claim 1 , wherein the seat control unit is configured to change at least one of an intensity, a time duration, a cyclic period and a timing of the stimulus in dependence on the alertness level. 
     
     
         4 . The vehicle seat according to  claim 1 , wherein the alertness level sensor includes a pulse sensor, a respiration sensor or a pressure sensor configured to detect a pressure distribution on a surface of the seat body opposing the driver. 
     
     
         5 . The vehicle seat according to  claim 1 , wherein the alertness level sensor includes a brainwave sensor provided on a part of the seat body opposing a head of the driver. 
     
     
         6 . The vehicle seat according to  claim 1 , wherein the seat control unit is configured to compute a sleep level of the driver including a distinction between a REM sleep and a non-REM sleep based on an output from the alertness level sensor when the alertness level is lower than a second alertness level threshold value which is lower than the first alertness level threshold value, and to change the stimulus provided to the driver according to the computed sleep level. 
     
     
         7 . The vehicle seat according to  claim 1 , wherein the seat control unit is configured to receive a signal predicting a time of the transition from the autonomous driving to the manual driving from the vehicle control device, and to activate the rousing unit in advance of the predicted time of the transition by a prescribed time period. 
     
     
         8 . The vehicle seat according to  claim 1 , wherein the seat control unit is configured to forward a vehicle stop signal to the vehicle control device when the seat control unit detects that the alertness level has continued to be below the first alertness level threshold value for a prescribed time period when the start signal is received. 
     
     
         9 . The vehicle seat according to  claim 1 , wherein the rousing unit includes at least one of a light source configured to irradiate light to the driver, a vibration source configured to provide vibration to the driver, a sound source configured to generate sound, a heat source configured to heat or cool at least a part of the driver's body, and an electrical stimulus generating source configured to apply an electrical stimulus to the driver. 
     
     
         10 . The vehicle seat according to  claim 1 , wherein the seat body is mounted on a vehicle body so as to be moveable between an autonomous driving position and a manual driving position, a drive unit for moving the seat body between the autonomous driving position and the manual driving position is provided between the seat body and the vehicle body, and the rousing unit is configured to cause the drive unit to move the seat body from the autonomous driving position to the manual driving position as the stimulus. 
     
     
         11 . The vehicle seat according to  claim 10 , further including an armrest which is moveable relative to the seat body, the rousing unit causing the armrest to move as the stimulus. 
     
     
         12 . The vehicle seat according to  claim 10 , wherein the seat body is mounted on the vehicle body so as to be rotatable around a vertical axial line, and the seat control unit is configured to allow the seat body to be rotated in the autonomous driving position and to place the seat body relative to the vehicle body to face forward in the manual driving position.