Vehicle control apparatus and vehicle control method

• US 8,706,402 B2
• Filed: 04/13/2010
• Issued: 04/22/2014
• Est. Priority Date: 04/13/2009
• Status: Expired due to Fees

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Suzuki, Takashi, Nakai, Koji
• Primary Examiner(s): Black, Thomas
• Assistant Examiner(s): Lewandroski, Sara
• Application Number:
  US12/759,078
• Publication Number:
  US 20100262317A1
• Time in Patent Office: 1,470 Days
• Field of Search: 701/411, 701/400, 701/416, 701/439, 701/80, 701/41, 701/116, 701/23, 700/245, 700/253
• US Class Current: 701/411
• CPC Class Codes: B60W 2552/20 Road profile, i.e. the change in elevation or curvature of a plurality of continuous road segments
• CPC Class Codes: B60W 2552/30 Road curve radius
• CPC Class Codes: B60W 2552/40 Coefficient of friction
• CPC Class Codes: B60W 30/18009 related to particular drive situations
• CPC Class Codes: B60W 30/18145 Cornering
• CPC Class Codes: B60W 50/0097 Predicting future conditions

Abstract

In a vehicle control, a future travel locus of a vehicle is computed by using an evaluation function, and travel road surface information regarding a travel road surface on which the vehicle travels is stored. According to the travel road surface information stored, a convergence criterion for the evaluation function is variably set.

Claims

1. A vehicle control device comprising:

circuitry that computes a future travel locus of a vehicle by using an evaluation function; and

a travel road surface information memory that stores travel road surface information regarding a travel road surface on which the vehicle travels, wherein

the circuitry variably sets a convergence criterion for the evaluation function according to the travel road surface information stored in the travel road surface information memory, the convergence criterion being related to a degree of priority of a computation time of the travel locus and a degree of priority of a computation accuracy of the travel locus, the convergence criterion being a function of an error, and the circuitry setting the error based on a road width of the travel road surface, radius of curve of the travel road surface, a friction coefficient of the travel road surface, and an allowed calculation time that elapses before control of the vehicle starts.

2. The vehicle control apparatus according to claim 1, wherein

the circuitry determines whether the future travel locus satisfies the convergence criterion.

3. A vehicle control method performed by a vehicle control apparatus that includes processing circuitry and a memory, the vehicle control method comprising:

computing, by the processing circuitry, a future travel locus of a vehicle by using an evaluation function;

storing, in the memory, travel road surface information regarding a travel road surface on which the vehicle travels; and

variably setting, by the processing circuitry, a convergence criterion for the evaluation function according to the travel road surface information stored, wherein;

the travel road surface information includes travelable width information regarding a road,

in computation of the travel locus, the computing computes an area of protrusion between a travelable width included in the travelable width information and a travel locus deviating from the travelable width by a Simpson method, and

the evaluation function represents the area of protrusion, and is proportional to a length of one section of a plurality of sections that are divided in the Simpson method.

4. A vehicle control method performed by a vehicle control apparatus that includes processing circuitry and a memory, the vehicle control method comprising:

computing, by the processing circuitry, a future travel locus of a vehicle by using an evaluation function;

storing, in the memory, travel road surface information regarding a travel road surface on which the vehicle travels;

variably setting, by the processing circuitry, a convergence criterion for the evaluation function according to the travel road surface information stored, the convergence criterion being related to a degree of priority of a computation time of the travel locus and a degree of priority of a computation accuracy of the travel locus;

computing, by the processing circuitry, an allowed calculation time that elapses before control of the vehicle starts, based on the travel road surface information stored by the storing in the memory, wherein;

the travel road surface information includes travelable width information regarding a road, and

the evaluation function is a function that evaluates amount by which the travel locus is protruded from the travelable width included in the travelable width information, and is proportional to a permissible error that is a predetermined permissible amount of the amount by which the travel locus is protruded; and

setting, by the processing circuitry, the permissible error greater, as the allowed calculation time becomes shorter.

5. A vehicle control method performed by a vehicle control apparatus that includes processing circuitry and a memory, the vehicle control method comprising:

computing, by the processing circuitry, a future travel locus of a vehicle by using an evaluation function;

storing, in the memory, travel road surface information regarding a travel road surface on which the vehicle travels; and

variably setting, by the processing circuitry, a convergence criterion for the evaluation function according to the travel road surface information stored, the convergence criterion being related to a degree of priority of a computation time of the travel locus and a degree of priority of a computation accuracy of the travel locus, wherein

the variably setting includes

determining the degree of priority of the computation time of the travel locus to be lower in response to the convergence criterion being higher, and

determining the degree of priority of the computation accuracy of the travel locus to be higher in response to the convergence criterion being lower.

6. A vehicle control apparatus comprising:

circuitry that computes a future travel locus of a vehicle by using an evaluation function; and

a travel road surface information memory that stores travel road surface information regarding a travel road surface on which the vehicle travels, wherein;

the circuitry variably sets a convergence criterion for the evaluation function according to the travel road surface information stored in the travel road surface information memory, the convergence criterion being related to a degree of priority of a computation time of the travel locus and a degree of priority of a computation accuracy of the travel locus, and

the circuitry computes an allowed calculation time that elapses before control of the vehicle starts, based on the travel road surface information stored in the travel road surface information memory, and variably sets the convergence criterion according to the allowed calculation time.

7. The vehicle control apparatus according to claim 6, wherein

the circuitry sets the convergence criterion greater, as the allowed calculation time becomes longer.

8. The vehicle control apparatus according to claim 6, wherein

in the control of the vehicle, motion of the vehicle is controlled.

9. The vehicle control apparatus according to claim 6, wherein

the control of the vehicle is performed based on the travel locus computed.

10. A vehicle control apparatus comprising:

circuitry that computes a future travel locus of a vehicle by using an evaluation function; and

a travel road surface information memory that stores travel road surface information regarding a travel road surface on which the vehicle travels, wherein;

the circuitry variably sets a convergence criterion for the evaluation function according to the travel road surface information stored in the travel road surface information memory,

the travel road surface information includes travelable width information regarding a road,

in computation of the travel locus, an area of protrusion between a travelable width included in the travelable width information and a travel locus deviating from the travelable width is computed by a Simpson method, and

the evaluation function represents the area of protrusion, and is proportional to a length of one section of a plurality of sections that are divided in the Simpson method.

11. A vehicle control apparatus comprising:

circuitry that computes a future travel locus of a vehicle by using an evaluation function; and

a travel road surface information memory that stores travel road surface information regarding a travel road surface on which the vehicle travels, wherein

the circuitry

variably sets a convergence criterion for the evaluation function according to the travel road surface information stored in the travel road surface information memory, the convergence criterion being related to a degree of priority of a computation time of the travel locus and a degree of priority of a computation accuracy of the travel locus,

determines the degree of priority of the computation time of the travel locus to be lower in response to the convergence criterion being higher, and

determines the degree of priority of the computation accuracy of the travel locus to be higher in response to the convergence criterion being lower.

12. The vehicle control apparatus according to claim 11, wherein

the circuitry repeatedly computes the future travel locus, the circuitry performing a lower number of repetitions of computation of the future travel locus in response to the degree of priority of the computation time of the travel locus being lower, and performing a higher number of repetitions of computation of the future travel locus in response to the degree of priority of the computation accuracy of the travel locus being higher.

13. A vehicle control apparatus comprising:

circuitry that computes a future travel locus of a vehicle by using an evaluation function; and

a travel road surface information memory that stores travel road surface information regarding a travel road surface on which the vehicle travels, wherein;

the circuitry variably sets a convergence criterion for the evaluation function according to the travel road surface information stored in the travel road surface information memory, the convergence criterion being related to a degree of priority of a computation time of the travel locus and a degree of priority of a computation accuracy of the travel locus,

the circuitry computes an allowed calculation time that elapses before control of the vehicle starts, based on the travel road surface information stored in the travel road surface information storage portion memory,

the travel road surface information includes travelable width information regarding a road,

the evaluation function is a function that evaluates amount by which the travel locus is protruded from the travelable width included in the travelable width information, and is proportional to a permissible error that is a predetermined permissible amount of the amount by which the travel locus is protruded, and

the permissible error is set greater, as the allowed calculation time becomes shorter.

14. A vehicle control method performed by a vehicle control apparatus that includes processing circuitry and a memory, the vehicle control method comprising:

computing, by the processing circuitry, a future travel locus of a vehicle by using an evaluation function;

storing, in the memory, travel road surface information regarding a travel road surface on which the vehicle travels;

variably setting, by the processing circuitry, a convergence criterion for the evaluation function according to the travel road surface information stored, the convergence criterion being related to a degree of priority of a computation time of the travel locus and a degree of priority of a computation accuracy of the travel locus, and the convergence criterion being a function of an error; and

setting, by the processing circuitry, the error based on a road width of the travel road surface, radius of curve of the travel road surface, a friction coefficient of the travel road surface, and an allowed calculation time that elapses before control of the vehicle starts.

15. A vehicle control method performed by a vehicle control apparatus that includes processing circuitry and a memory, the vehicle control method comprising:

computing, by the processing circuitry, a future travel locus of a vehicle by using an evaluation function;

storing, in the memory, travel road surface information regarding a travel road surface on which the vehicle travels;

variably setting, by the processing circuitry, a convergence criterion for the evaluation function according to the travel road surface information stored, the convergence criterion being related to a degree of priority of a computation time of the travel locus and a degree of priority of a computation accuracy of the travel locus;

computing an allowed calculation time preceding start of control of motion of the vehicle based on the travel road surface information stored; and

variably setting the convergence criterion according to the allowed calculation time.

16. The vehicle control method according to claim 15, wherein

the convergence criterion is set greater, as the allowed calculation time becomes longer.