Automatic braking system
A braking system suitable for use on an automated vehicle includes a ranging-sensor, a braking-actuator, and a controller. The ranging-sensor detects reflections indicative of objects present in a field-of-view proximate to a host-vehicle. The braking-actuator controls movement of the host-vehicle. The controller is in communication with the ranging-sensor and the braking-actuator. The controller determines a region-of-interest within the field-of-view and defines an occupancy-grid that segregates the field-of-view into an array of grid-cells. The controller further determines a repeatability-of-detection of each of the grid-cells based on reflections detected by the ranging-sensor. The controller further determines that a rigid-object is present in the field-of-view when each of a string of the grid-cells are characterized by the repeatability-of-detection greater than a repeatability-threshold. The controller activates the braking-actuator when the string intersects the region-of-interest.
1. A braking system suitable for use on an automated vehicle, said system comprising:
a ranging-sensor that detects reflections indicative of objects present in a field-of-view proximate to a host-vehicle;
a braking-actuator that controls movement of the host-vehicle; and
a controller in communication with the ranging-sensor and the braking-actuator, said controller determines a region-of-interest within the field-of-view, defines an occupancy-grid that segregates the field-of-view into an array of grid-cells, determines a repeatability-of-detection of each of the grid-cells based on reflections detected by the ranging-sensor, determines that a rigid-object is present in the field-of-view when each of a string of the grid-cells are characterized by the repeatability-of-detection greater than a repeatability-threshold, and activates the braking-actuator when the string intersects the region-of-interest; wherein the string includes at least three grid-cells.
2. The system in accordance with claim 1 , wherein the controller includes a memory and a temporal-history of the occupancy-grid is stored in the memory.
3. The system in accordance with claim 2 , wherein the controller further determines an estimated-distance to the rigid-object based on the temporal-history and activates the braking-actuator when the rigid-object has moved out of the field-of-view and the estimated-distance is less than a distance-threshold.
4. The system in accordance with claim 1 , wherein a dimension of the grid-cell is not greater than five centimeters on each side.
5. The system in accordance with claim 4 , wherein the repeatability-threshold is at least two detections in a grid-cell.
6. The system in accordance with claim 1 , wherein the ranging-sensor is a radar-sensor.
7. The system in accordance with claim 1 , wherein the ranging-sensor is a lidar-sensor.
8. A method of operating a braking system suitable for using in an automated vehicle, said method comprising:
detecting, using a ranging-sensor, reflections indicative of objects present in a field-of-view proximate to a host-vehicle;
controlling movement of the host-vehicle using a braking-actuator; and
determining, with a controller in communication with the ranging-sensor and the braking-actuator, a region-of-interest within the field-of-view, defining an occupancy-grid that segregates the field-of-view into an array of grid-cells, determining a repeatability-of-detection of each of the grid-cells based on reflections detected by the ranging-sensor, determining that a rigid-object is present in the field-of-view when each of a string of the grid-cells are characterized by the repeatability-of-detection greater than a repeatability-threshold, and activating the braking-actuator when the string intersects the region-of-interest; wherein the string includes at least three grid-cells.
9. The method in accordance with claim 8 , wherein the controller includes a memory, further comprising the step of storing a temporal-history of the occupancy-grid in the memory.
10. The method in accordance with claim 9 , further comprising the step of determining with the controller an estimated-distance to the rigid-object based on the temporal-history and activating the braking-actuator when the rigid-object has moved out of the field-of-view and the estimated-distance is less than a distance-threshold.
11. The method in accordance with claim 8 , wherein a dimension of the grid-cell is five centimeters or less on each side.
12. The method in accordance with claim 11 , wherein the repeatability-threshold is at least 2 detections in a grid-cell.
13. The method in accordance with claim 8 , wherein the ranging-sensor is a radar-sensor.
14. The method in accordance with claim 8 , wherein the ranging-sensor is a lidar-sensor.
15. An automated vehicular braking system comprising:
a ranging-sensor;
a braking-actuator; and
a controller in communication with the ranging-sensor and the braking-actuator, wherein said controller captures a series of detection-patterns from the ranging-sensor and assigns the detection-patterns into an array of grid-cells to detect a potential obstruction, compares the detection-patterns to determine a rate-of-consistency, and engages the braking-actuator when the rate-of-consistency within a string of at least three grid-cells exceeds a pre-determined threshold.