Travel control device

• US 9,045,118 B2
• Filed: 09/01/2008
• Issued: 06/02/2015
• Est. Priority Date: 09/05/2007
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Taguchi, Koji, Nakai, Koji
• Primary Examiner(s): Trammell, James
• Assistant Examiner(s): Stroud, James E
• Application Number:
  US12/673,249
• Publication Number:
  US 20100211235A1
• Time in Patent Office: 2,465 Days
• Field of Search: 701/11, 701/15, 701/13
• US Class Current: 1/1
• CPC Class Codes: B60T 2201/022 Collision avoidance systems
• CPC Class Codes: B60T 7/22 initiated by contact of vehicle, e.g. bumper, with an external object, e.g. another vehicle , or by means of contactless obstacle detectors mounted on the vehicle
• CPC Class Codes: B60T 8/174 characterised by using special control logic, e.g. fuzzy logic , neural computing
• CPC Class Codes: B60T 8/1755 Brake regulation specially adapted to control the stability of the vehicle, e.g. taking into account yaw rate or transverse acceleration in a curve road vehicle drive control systems for control of driving stability otherwise than by controlling a particular sub-unit B60W30/02
• CPC Class Codes: B60T 8/17557 specially adapted for lane departure prevention road vehicle drive control systems for lane keeping otherwise than by controlling a particular sub-unit B60W30/12
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/184 with wheel brakes
• CPC Class Codes: B60W 10/20 including control of steering systems
• CPC Class Codes: B60W 2050/0022 Gains, weighting coefficients or weighting functions
• CPC Class Codes: B60W 2050/0024 Variable gains
• CPC Class Codes: B60W 2520/105 Longitudinal acceleration
• CPC Class Codes: B60W 2520/14 Yaw
• CPC Class Codes: B60W 2556/50 of positioning data, e.g. GPS [Global Positioning System] data
• CPC Class Codes: B60W 2720/103 Speed profile
• CPC Class Codes: B60W 30/09 Taking automatic action to avoid collision, e.g. braking and steering
• CPC Class Codes: B60W 30/10 Path keeping cruise control for automatically following a preceding vehicle B60W30/165
• CPC Class Codes: B60W 50/0097 Predicting future conditions

Abstract

A travel control device which controls vehicle travel by feedback control so that the vehicle travels according to a travel plan is characterized by including: a control item determining unit that determines a prioritized control item for every position of a target locus in the travel plan; a control gain determining unit that sets a control gain of the determined prioritized control item to be higher than those of other control items; and a travel plan correction unit that includes the determined control gain in the travel plan.

Claims

1. A travel control device which controls vehicle travel by feedback control so that the vehicle travels according to a travel plan, wherein a target locus comprises a plurality of positions of the vehicle in a time series which the vehicle needs to pass in a future, the travel plan includes the target locus and vehicle state amount at each point included in the target locus, a plurality of control items are the vehicle state amount of an object of feedback control, a control gain of the feedback control is set in the plurality of control items respectively, the control gain is a level for trying to reduce an error of the actual vehicle state amount with respect to a control target value, the feedback control can be performed such that the error decreases as a value of the control gain increases, and the feedback control is performed such that the error of the actual vehicle state amount with respect to the control target value decreases using the control gain of the plurality of control items, the travel control device comprising:

a control item determining unit that determines a prioritized control item among the plurality of control items for each of the plurality of positions of the vehicle of the target locus in the time series, the plurality of positions includes an early stage and a middle stage;

a control gain determining unit that sets the control gain of the prioritized control item determined by the control item determining unit to be higher than the control gain of other control items among the plurality of control items; and

a travel plan correction unit that includes the control gain determined by the control gain determining unit in the travel plan,

wherein, for each of the plurality of positions of the vehicle of the target locus in the time series, the error with respect to the control target value of the prioritized control item is further decreased than the error with respect to the control target value of the other control items by increasing the control gain while allowing the error with respect to the control target value of other control item to increase due to the decrease of the control gain,

when the vehicle performs emergency avoidance, the control gain determining unit sets the control gain of the prioritized control item regarding a high yaw rate and/or a low speed to be higher than the control gain of other control items in the early stage of the time series from a start of the emergency avoidance to an end of the emergency avoidance and sets the control gain of the prioritized control item regarding a high lateral acceleration and/or a high lateral speed to be higher than the control gain of the other control items in the middle stage of the time series, and

the control item regarding the high yaw rate is the control item for generating a high yaw rate in order to change direction of the vehicle to avoid an obstacle, the control item regarding the low speed is the control item for reducing speed of the vehicle to avoid approaching an obstacle, the control item regarding the high lateral acceleration is for generating a high lateral acceleration for moving the vehicle in a lateral direction to avoid an obstacle without fail, and the control item regarding the lateral speed is for generating a high lateral speed for moving the vehicle in a lateral direction to avoid an obstacle without fail.

2. The travel control device according to claim 1, wherein

the plurality of positions further includes a final stage,

the control gain determining unit sets the control gain of the control item regarding a proper lateral position and/or a proper speed to be higher than the control gain of the other control items in the final stage of the time series from the start of the emergency avoidance to the end of the emergency avoidance, and

the control item regarding the proper lateral position is for setting the vehicle at a proper lateral position required when traveling along an adjacent lane after the movement in the lateral direction to avoid the obstacle and the control item regarding the proper speed is for the vehicle to travel at a proper speed required when travelling along the adjacent lane after the movement in the lateral direction.