Object height determination for automated vehicle steering control system

A steering-system for an automated vehicle is provided. The system includes an object-detector and a controller. The object-detector indicates a height and/or a width of an object approached by a host-vehicle. The controller is configured to steer the host-vehicle and is in communication with the object-detector. The controller steers the host-vehicle to straddle the object when the height of the object is less than a ground-clearance of the host-vehicle, and/or the width of the object is less than a track-width of the host-vehicle.

TECHNICAL FIELD OF INVENTION

This disclosure generally relates to a steering-system for an automated vehicle, and more particularly relates to a system that steers a host-vehicle to straddle the object when the height of the object is less than a ground-clearance of the host-vehicle and/or the width of the object is less than a track-width of the host-vehicle.

BACKGROUND OF INVENTION

It has been observed that an automated vehicle may unnecessarily drive around object that is actually low enough to drive over, i.e. straddle.

SUMMARY OF THE INVENTION

In accordance with one embodiment, a steering-system for an automated vehicle is provided. The system includes an object-detector and a controller. The object-detector indicates a height and/or a width of an object approached by a host-vehicle. The controller is configured to steer the host-vehicle and is in communication with the object-detector. The controller steers the host-vehicle to straddle the object when the height of the object is less than a ground-clearance of the host-vehicle, and/or the width of the object is less than a track-width of the host-vehicle.

DETAILED DESCRIPTION

FIG. 1illustrates a non-limiting example of a steering-system10, hereafter referred to as the system10, which is suitable for use on an automated vehicle, e.g. a host-vehicle12. As used herein, the term automated vehicle may apply to instances when the host-vehicle12is being operated in an automated-mode14, i.e. a fully autonomous mode, where a human-operator (not shown) of the host-vehicle12may do little more than designate a destination in order to operate the host-vehicle12. However, full automation is not a requirement. It is contemplated that the teachings presented herein are useful when the host-vehicle12is operated in a manual-mode16where the degree or level of automation may be little more than providing an audible or visual warning to the human-operator who is generally in control of the steering, accelerator, and brakes of the host-vehicle12. For example, the system10may merely assist the human-operator as needed to change lanes and/or avoid a collision with, for example, an object20in the travel-path22(FIG. 2) of the host-vehicle12.

The system10includes an object-detector24that may be formed of, but not limited to, a camera, a lidar, a radar, an ultrasonic-transducer, or any combination thereof. WhileFIG. 1may be interpreted to suggest that the devices that form the object-detector24are co-located in a unified assembly, this is not a requirement. It is contemplated that the various devices may be mounted at distributed locations on the host-vehicle12. Indeed, it is recognized that different types of devices provide more useful information about the object20when placed at different locations on the host-vehicle12, as will become apparent in the description of the system10that follows.

The system10includes a controller26configured to operate the host-vehicle12using vehicle-controls to steer, brake, and/or accelerate the host-vehicle12. The means by which the controller26is able to control the steering, accelerator, and brakes of the host-vehicle12are well-known to those in the art. The controller26is in communication with the object-detector24. The communication may be by way of wires, optical-cable, a data-buss, or wireless communications, as will be recognized by those in the art. The controller26may include a processor (not specifically shown) such as a microprocessor or other control circuitry such as analog and/or digital control circuitry including an application specific integrated circuit (ASIC) for processing data as should be evident to those in the art. The controller26may include memory (not specifically shown), including non-volatile memory, such as electrically erasable programmable read-only memory (EEPROM) for storing one or more routines, thresholds, and captured data. The one or more routines may be executed by the processor to perform steps for determining how to operate the host-vehicle12with respect to the object20based on signals received by the controller26from the object-detector24as described herein.

FIG. 2illustrates a non-limiting example of an object20present in a travel-path22of the host-vehicle12(not shown inFIG. 2). In this non-limiting example, the object is a partial-section of a log that may have fallen from a logging-truck. As mentioned previously, it has been observed that automated-vehicles may unnecessarily avoid an object that is small enough to straddle28(FIG. 1). As used herein, to straddle the object20means that the host-vehicle drives over the object20in a manner such that the effect is that the object20passes between the wheels (not shown) of the host-vehicle12, and preferably does not make contact with the undercarriage of the host-vehicle12. That is, the controller26steers the host-vehicle12to straddle28the object20when a height30of the object20is less than a ground-clearance32of the host-vehicle12and/or a width34of the object20is less than a track-width36(i.e. lateral distance between tires) of the host-vehicle12.

The object-detector24may be particularly configured to indicate the height30of the object20approached by a host-vehicle12. For example, the object-detector24may include a lidar and/or a camera mounted at a relatively low location on the host-vehicle12, at bumper-height for example. From this location, data from the lidar and/or images from the camera can be readily used by the controller26determine if the height30of the object20is greater than or less than the ground-clearance32of the host-vehicle12. However, a relatively low location is not a requirement as those in the art will recognize that data/images from various devices mounted at a relatively high position can be fused and analyzed using known geometry techniques that consider distance from the host-vehicle12to the object20to determine the height30of the object20.

Alternatively, one or more instance of ultrasonic-transducers may also be mounted on the front bumper of the host-vehicle and oriented to ‘look-down’ towards the surface of the travel-path22. While this configuration may not provide much in the way of advance warning, it may be helpful to determine if the host-vehicle12can straddle the object20when the height30of the object20is very close to the ground-clearance32of the host-vehicle12.

It is recognized that the ground-clearance32is not necessarily a fixed value for the entire area that is inside of the track-width36. Accordingly, the ground-clearance32may be represented by an end-view profile of the undercarriage of the host-vehicle12. For example, the host-vehicle12may be able to straddle an object with a greater peak height if the object20passes under the center of the host-vehicle12rather than off-center and near a tire. It is recognized that the object20does not actually pass under the host-vehicle12, but rather the host-vehicle12passes over the object20when the host-vehicle12straddles the object20. However, conceptually, the object20can be described as passing under the host-vehicle12.

The object-detector24may also be particularly configured to indicate the width34of the object20approached by the host-vehicle12. By way of a non-limiting example, the lidar may include a lateral array of laser emitters arranged across the width of the host-vehicle12so each of the emitters emits a laser-beam parallel to each other and aligned with the straight-ahead travel-direction of the host-vehicle12. Each of the beams may be scanned vertically so the width34of the object20can be determined regardless of the height30and the distance to the object20. However, this configuration is not a requirement as those in the art will recognize that data/images from various devices mounted elsewhere on the host-vehicle can be fused and analyzed using known geometry techniques that consider distance from the host-vehicle12to the object20to determine the width34of the object20.

It may also be advantageous for the object-detector24to be configured to determine a length38of the object20. Knowing the length38may be useful to provide a confidence level to the determination of the height30and the width34. For example, if the object20is relatively long, more than two meters for example, the height30and/or the width34may change over the length38of the object20. It is contemplated that certain configurations of the object-detector24may do well at detecting the height30and width34of the forward-face or leading-edge of the object20closest to the host-vehicle12, but be unable to reliably detect the height30and/or width34trailing-edge of the object farthest from the host-vehicle12. Accordingly, the controller26may limit the use of information from the object-detector24that is gathered from a distance that exceeds a detector-range40. The value of the detector-range40may be determined empirically and/or analytically, and will likely be different for different configurations of the object-detector24and different models of the host-vehicle12.

The length38may be determined using a camera, a lidar, a radar, or any combination thereof mounted at a relatively high location on the host-vehicle12, on the roof of the host-vehicle12for example. Given an elevated perspective view, data from one or more of these devices can be fused and analyzed using known geometry techniques that consider distance from the host-vehicle12to the object20to determine the length38of the object20.

Referring again toFIG. 2, if the height30and the width34of the object20are such the host-vehicle12is able to straddle28the object20, then the controller26may elect to do so. That is, the controller26may steer the host-vehicle12to straddle28the object20when the height30of the object20is less than the ground-clearance21of the host-vehicle12, and the width34of the object20is less than the track-width36of the host-vehicle. However, the controller26may elect to steer-around42if the length38of the object20puts the trailing edge of the object20past the detector-range40. The controller26may also steer-around the object20when the height30of the object20is not less than the ground-clearance21of the host-vehicle12or the width34of the object20is not less than the track-width36of the host-vehicle.

FIG. 2shows an approaching-vehicle44and road-markers46that will prevent, at least temporarily, the host-vehicle12being operated to steer-around42the object20. Until the approaching-vehicle44passes, and no other vehicles are approaching, the controller26may be configured to stop48the host-vehicle12until the situation is such that the host-vehicle12can steer-around42the host-vehicle.

Accordingly, a steering-system (the system10), a controller26for the system10, and a method of operating the system10is provided. The system10provides the means for an automated vehicle to determine if an object20in the travel-path22of the host-vehicle12can either straddle28, or steer-around42the object20, or if the host-vehicle12must stop48and wait for an opportunity to steer-around42the host-vehicle12.