METHOD FOR CONTROLLING THE PATH OF AN AUTONOMOUS VEHICLE HAVING STEERED WHEELS

• US 20150185734A1
• Filed: 07/01/2013
• Published: 07/02/2015
• Est. Priority Date: 07/12/2012
• Status: Active Grant

• Current Assignee: Renault Sas (Renault)
• Original Assignee: Renault Sas (Renault)
• Inventors: Minoiu-Enache, Nicoleta
• Granted Patent: US 9,535,422 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G01C 21/3415 Dynamic re-routing, e.g. recalculating the route when the user deviates from calculated route or after detecting real-time traffic data or accidents
• CPC Class Codes: G05D 1/0223 involving speed control of the vehicle vehicle fittings for automatically controlling, i.e. preventing speed from exceeding an arbitrarily established velocity or maintaining speed at a particular velocity, as selected by the vehicle operator B60K31/00

Abstract

A method for controlling the position and speed of a vehicle having steered wheels includes, determining an overall path comprising a plurality of points and defining the course of the vehicle between a starting point and an endpoint; determining the current position of the vehicle; if the current position does not correspond to a point on the overall path, generating a local path connecting the current position of the vehicle to a point on the overall path; and generating control signals in order to steer the steered wheels and control the speed of the vehicle so that the vehicle moves along the local path. The control signals are generated by convex optimisation of linear matrix inequalities.

Claims

1. A method for controlling the position and speed of a vehicle capable of moving in an autonomous manner and having at least one steered wheel, said method comprising the following steps:

determining (E1) an overall path defining the course of the vehicle between a starting point and an endpoint, said overall path comprising a plurality of intermediate points between the starting point and the endpoint, a position being defined for each point of the overall path;

determining (E2) the current position of the vehicle;

if the current position does not correspond to a point on the overall path, generating (E3) a local path connecting the current position of the vehicle to a point on the overall path, said local path comprising a plurality of points, a position and a speed being defined for each point of the local path;

generating (E4) a steering control signal for the steered wheel and a speed control signal for the vehicle so that the vehicle moves along said local path;

characterized in that the steering and speed control signals are generated by convex optimization of linear matrix inequalities.

2. The method as claimed in claim 1, characterized in that the generation of the steering control signal and of the speed control signal comprises the following steps:

determining a kinematic model for the vehicle; and

determining the steering and speed control signals on the basis of said kinematic model by convex optimization of linear matrix inequalities.

3. The method as claimed in claim 2, characterized in that the kinematic model of the vehicle is determined on the basis of a kinematic model of a robot having two independent wheels, the kinematic model of the robot being supplemented by a plurality of constraints specific to vehicles having steered wheels.

4. The method as claimed in claim 3, characterized in that said plurality of constraints specific to vehicles having steered wheels comprises:

a stability constraint which is asymptotic with respect to the local path;

a constraint of limitation of curvature of the local path;

a constraint of continuity and derivability of the steering and speed control signals; and

a constraint for the feasibility of transposing the kinematic model from a robot having two independent wheels to a vehicle having at least one steered wheel.

5. The method as claimed in claim 4, characterized in that the kinematic model is supplemented with one or more constraints from among the following:

a constraint of limitation of the variation of the control signals;

a constraint on the starting area of the control signals;

a constraint on the placing of the closed-loop poles of the model.

6. A device for controlling the position and speed of a vehicle capable of moving in an autonomous manner and having at least one steered wheel, said device comprising:

a location and navigation circuit (10) for determining;

an overall path defining the course of the vehicle between a starting point and an endpoint, said overall path comprising a plurality of intermediate points between the starting point and the endpoint, a position being defined for each point of the overall path;

the current position of the vehicle;

if the current position does not correspond to a point on the overall path, generation of a local path connecting the current position of the vehicle to a point on the overall path, said local path comprising a plurality of points, a position and a speed being defined for each point of the local path;

a computer (11) for generating a steering control signal for the steered wheel and a speed control signal for the vehicle so that the vehicle moves along said local path;

characterized in that the computer generates the steering and speed control signals by convex optimization of linear matrix inequalities.