Vehicle Driving Aid and Method and Improved Related Device

• US 20080252433A1
• Filed: 09/08/2006
• Published: 10/16/2008
• Est. Priority Date: 09/09/2005
• Status: Abandoned Application

• Current Assignee: Institut National de Recherche en informatique et en Automatique, Probayes Co.
• Original Assignee: Inria Institut National de Recherche EN Informatique et EN Automatique, Probayers
• Inventors: Laugier, Christian, Yguel, Manuel, Mekhnacha, Kamel
• Application Number:
  US12/066,265
• Publication Number:
  US 20080252433A1
• Time in Patent Office: Days
• US Class Current: 340/435
• CPC Class Codes: G08G 1/161 Decentralised systems, e.g. inter-vehicle communication
• CPC Class Codes: G08G 1/164 Centralised systems, e.g. external to vehicles

Abstract

A vehicle driving aid method includes and defining an occupation grid corresponding to discretization into N cells of a field of kinematic parameters of a detected object; acquiring at each time k an observation z^k produced by a sensor and determining a sensor probability modeling the behavior thereof; calculating for each cell X, a predicted occupation probability providing the probability that the cell X is, at time k, in occupied state having knowledge of a density of estimated of occupation of the grid a the preceding time; calculating for each cell X, an estimated probability of occupation providing the sensor probability and predicted occupation probability; the latter at time k determined by supposing that a single cell of the grid constitutes, at time k−1, the antecedent of the cell X concerned; evaluating, for each cell X, a collision probability, based on the estimated probability at time k and emitting a signal to avoid the object.

Claims

1. Method for aiding the driving of a vehicle comprising at least one sensor able to deliver an output signal indicative of the presence of at least one object in a detection zone, said method comprising the steps of:

defining a grid corresponding to discretization into cells of a space of kinematic parameters of said object relative to said vehicle;

and, at each sampling time k;

determining an observation z^k from said output signal of the sensor;

and, for each cell x of the grid;

determining, from said observation z^k, the value of a sensor probability p(z^k|E^k_xX) modeling the behavior of said sensor;

calculating an estimated value of occupancy at time k, based on the probability P(E^k_xX|z<sup>0;

k</sup>=z⁰ . . . z^k) that the cell x is in state E^k_x at time k, given the observation z^k;

said estimated value of occupancy at time k depending on said sensor probability p(z^k|E^k_xX) and on a predicted occupancy value P(E^k_xX|z<sup>0;

k−

1</sup>=z<sup>k−

1</sup>) at time k;

determining said predicted occupancy value P (E^k_xX|z<sup>0;

k−

1</sup>=z⁰ . . . z<sup>k−

1</sup>) at time k, based on the probability that considered cell x is in state E^k_x at time k, by taking into account the observations from an initial time 0 to time k−

1;

said predicted occupancy value at time k being determined by approaching a relation of this type;

$P<br><br>\left(E_X^k,X|z^{0;<br><br>k-1}\right)={\int <br><br>}_{\left(E_X^{k-1},X^{\mathrm{\prime <br><br>}}\right)}<br><br>P<br><br>\left(E_X^k,X|E_{X^{\mathrm{\prime <br><br>}}}^{k-1},X^{\mathrm{\prime <br><br>}}\right)<br><br>P<br><br>\left(E_{X^{\mathrm{\prime <br><br>}}}^k,X^{\mathrm{\prime <br><br>}}|z^{0<br><br>\text{;<br><br>}<br><br>k-1}\right)$

in which intervene the estimated probability of occupancy at time k−

1 for each of cells X′

of the grid, considering that the probability of transition from any cell to the considered cell is not null for only a cell said antecedent to said considered cell;

evaluating, for each cell of the grid, a collision hazard probability from said estimated value of occupancy at time k;

outputting a control signal to an actuator based on the collision hazard probabilities of the cells of the grid in order to avoid said detected object.

2. Method according to claim 1, characterized in that said occupancy value is equal to said probability of occupancy.

3. Method according to claim 1, characterized in that said occupancy value is compatible with a compression transform.

4. Method according to claim 1, characterized in that, being defined an occupancy grid which associates with each cell of the grid a first quantity depending on the probability of occupancy of said cell, a compression transform is applied to said occupancy grid to obtain an equivalent representation of said occupancy grid, said occupancy value being a second occupancy value associated with said equivalent representation of said occupancy grid.

5. Method according to claim 3, characterized in that the first estimated value of occupancy at time k is the logarithm of the ratio between the estimated occupancy probability at time k that the considered cell is occupied and the estimated occupancy probability at time k that the considered cell is empty.

6. Method according to claim 1, characterized in that said grid comprises more than 10 million cells.

7. Method according to claim 1, characterized in that, said grid being a spatial grid obtained by discretization of the space of positions of said object with a predefined pitch, said method comprises an additional step of determining a set of possible speeds, said possible speeds being the ones that enable to pass exactly from a cell of the grid to another cell of the grid in a finite number n of sampling steps.

8. Method according to claim 7, characterized in that a spatial grid is associated with each one of the possible speeds, and in that said steps of said method are executed for each grid taken separately from the others, a constant speed of said detected object being assumed.

9. Method according to claim 7, characterized in that said spatial grid comprises more than 1 million cells.

10. Method according to claim 1, characterized in that said sampling period is smaller than 10 ms.

11. Device for aiding the driving of a vehicle, characterized in that it comprises means able to implement the driving aid method according to claim 1.

12. Device according to claim 11, characterized in that it comprises N processors, N being the number of cells of said grid, each processor working in parallel with the other processors and calculating at each sampling time k the estimated value of occupancy of cell X it represents.

13. Method according to claim 4, characterized in that the first estimated value of occupancy at time k is the logarithm of the ratio between the estimated occupancy probability at time k that the considered cell is occupied and the estimated occupancy probability at time k that the considered cell is empty.

14. Method according to claim 2, characterized in that said grid comprises more than 10 million cells.

15. Method according to claim 2, characterized in that, said grid being a spatial grid obtained by discretization of the space of positions of said object with a predefined pitch, said method comprises an additional step of determining a set of possible speeds, said possible speeds being the ones that enable to pass exactly from a cell of the grid to another cell of the grid in a finite number n of sampling steps.

16. Method according to claim 8, characterized in that said spatial grid comprises more than 1 million cells.