1. Technical Field
This invention relates to vehicle park assist systems used for automatic or semi-automatic control of a vehicle steering system.
2. Background Art
Vehicle park assist systems are used to identify a feasible parking space, e.g., usually a parallel space, a rear perpendicular space, or a garage parking space, and then take over control of the steering of the vehicle to maneuver the vehicle into the identified space hands free. In most such system, during operation of the park assist system the driver retains manual control over the transmission, acceleration, and/or brakes of the vehicle. Thus, while the steering is done automatically, the driver is still responsible for the safe parking of the vehicle.
U.S. patent application Ser. No. 12/574840, assigned to the assignee of the present application, discloses a park assist system and method of the general type described above.
The present application describes various embodiments of a park assist system and a method for operating a park assist system. In one embodiment, a system for aiding in parking a vehicle in a parking space comprises a sensing system detecting objects that define the parking space, and a control module identifying the parking space, controlling a vehicle steering system, and prompting a vehicle driver to park the vehicle in the parking space. The control module further controls the steering system to achieve a centered condition after the vehicle is properly parked. Returning the steering system to the centered condition allows the driver to move the vehicle forward and/or rearward somewhat as desired without disturbing the proper alignment of the vehicle. It also removes the need for the driver to manually turn the steering wheel while the vehicle is stationary. Having the steering wheel in the centered position is also advantageous since it prevents spokes of the steering wheel from obstructing the driver's view of any displays on the instrument panel that are immediately in front of the steering wheel.
According to another embodiment disclosed herein, a park assist system for parking a vehicle in a parking space comprises a control module that receives signals from a sensing system, identifies the parking space, operates a vehicle steering system and prompts a driver to park the vehicle in the parking space, and operates the steering system to a centered condition after a final movement of the vehicle into the parking space.
According to another embodiment, a method for parking a vehicle in a parking space comprises using a park assist system including a sensor to scan neighboring objects and detect the parking space, automatically operating a vehicle steering system and prompting a driver to take actions to park the vehicle in the parking space, and after the vehicle is in a parked condition in the parking space, automatically operating the steering system to a centered condition.
Other features and advantages of the park assist system will become apparent to those skilled in the art from the following detailed description, when read in light of the accompanying drawings.
In the exemplary embodiment shown schematically in
In the illustrated embodiment, the sensing system 26 is operatively connected to the PACM 30 to provide input signal(s) thereto. Sensing system 26 includes sensors for sensing the vehicle environment, such as ultrasonic sensors 27, optical (artificial vision) sensors 29, radar, lidar, thermal sensors, and/or GPS (not shown). As depicted in
Sensing system 26 may also include sensors for detecting the status or mode of operation of various systems on-board the vehicle V, such as odometric sensors (not shown) and/or a steering wheel angle sensor 24. The odometric sensors may be located on one or more of the wheels 22 of the vehicle V and/or in the driveline system 20 of the vehicle. The steering wheel angle sensor 24 is associated with the steering system 18 of the vehicle and may, for example, be located on a steering wheel 31 or steering column. Alternatively, the construction and/or the components of the sensing system 26 of the vehicle V may be other than illustrated and described if so desired.
The vehicle V may also be equipped with a video display screen 40 for the display of various types of information to the driver. The vehicle V may also include an audio interface device 42 such as a speaker, chime, buzzer, or other device for generating sound.
In the embodiment shown in
PACM 30 includes a data processing component that processes the information from the sensor(s) to evaluate whether the vehicle 10 may be successfully parking in parking space 10. The data processing component may, for example, be a micro-computer based device, as is well known. The evaluation by PACM 30 may involve determining if a valid steering trajectory T can be performed to park the vehicle V in the parking space 10. If a valid steering trajectory T exists, the PACM deems the parking space 10 to be a feasible parking space. The calculations performed by the PACM 30 may include a determination of a required slot length 34 depending upon considerations such as a length 36 of the vehicle V, and/or an achievable turning radius of the vehicle, and/or any other geometric considerations related to the vehicle and/or any other objects in the vicinity of parking space 10.
The movement of the vehicle along the steering trajectory T may be performed in one or more parking maneuvers as may be necessary until it is properly parked. As used herein, one parking maneuver is defined as (1) moving the vehicle rearwardly from a stop into the parking space, (2) stopping the vehicle briefly within the parking space, (3) moving the vehicle forward within the parking space, and (4) then stopping and thus parking the vehicle. At least one actuation or movement of the steering system 18 is usually required in association with each of the steps in the parking maneuver to achieve the required trajectory T. A subsequent rearward and/or forward movement of the vehicle, as may be necessary if the parking space is too short relative to the vehicle length and/or turning radius, defines an additional parking maneuver.
Once it is determined that the vehicle 10 is properly parked in a desired parked condition, the PACM 30 operates the steering system 18 to return it to a centered condition. In the disclosed embodiment, this involves actuating the electric motor 24 to move the steering wheel 31 and associated components of the steering system 18 so that the steerable road wheels of the vehicle are aligned parallel with the longitudinal (front-to-rear) axis of the vehicle. In this condition, the steering wheel 31 will be oriented in a centered condition, so that any spokes or similar structure of the steering wheel are not blocking the driver's view of displays on the instrument panel.
Referring now to
If the parking space is determined at step 100 to be feasible for parking, the driver is notified or alerted at step 110 that a feasible parking space is available. The notification may be delivered via a visual and/or audible signal interface. One example of a visual interface that may be used is a text message displayed in a message center in the vehicle instrument panel. Alternatively, the visual interface may be a graphic image, icon, or other non-text representation on a video display screen. Such a visual interface may be located at any appropriate location in the vehicle, such as an overhead console.
Next, at step 120 the driver is instructed to stop the vehicle and to accept the system assistance to park. This instruction may be delivered visually and/or audibly, and may be accomplished by the same interface(s) used in step 110. Once the driver has stopped the vehicle, at step 130 the driver is prompted to remove his or her hands from a steering control device of the steering system (a steering wheel, for example) and to actuate a brake control device (such as a brake pedal) and a transmission control device (such as a gear select lever or button) to engage or shift the transmission of the powertrain system 28 into reverse gear.
At step 140, the park assist system takes over control of the steering system 24 to execute the calculated steering trajectory T. The park assist system generates signals to prompt the driver to take actions necessary to drive the vehicle backwards and pull forward (in one or more parking maneuvers) to achieve a parked condition of the vehicle V in the parking space 10. The parked condition may be defined, depending upon the nature and dimensions of the parking space, as when the vehicle is within a certain distance of one or more of the objects or features that define the space and/or within a certain angular measure of being parallel with the appropriate objects/features.
The driver actions prompted at step 140 may include actions such as actuating a brake control device to control the speed of the vehicle and/or actuating a transmission control device to engage or shift the transmission of the powertrain system 28 between forward and reverse gears.
As indicated at step 150, the method may optionally include displaying to the driver an image of the vehicle and/or parking space environment. For example, an image from a rear view camera 29 may be displayed on a video display screen. In another example, a simulated or virtual top view showing the vehicle and its location relative to the parking space may be displayed. Either of these images may be overlaid with lines and/or other symbols depicting the desired steering trajectory T.
When the park assist system has determined that the vehicle is properly parked and the final movement of the parking maneuver is complete, the method progresses to step 160 where the steering system is operated to place it in a centered condition. This may involve actuating an electric motor that provides power boost to the steering system so as to move the steering wheel along with associated components of the steering system until the steerable vehicle wheels are parallel with the longitudinal axis of the vehicle. Ending the park assist sequence with the steering system centered allows the driver to make any desired forward and/or rearward adjustments to the vehicle's position without concern about whether the steering system is turned to the left or right in a manner that would disturb the alignment of the vehicle. Also, the driver is saved from having to turn the steering wheel manually to achieve the centered condition.
When the steering system is in the centered condition, the steering wheel will be oriented in a centered or upright condition so that any spokes or similar structure of the steering wheel are not blocking the driver's view of displays on the instrument panel.
Although the parking space 10 has been described as a parallel parking space between a forward first object and a rearward second object, the parking space may alternatively be a rear perpendicular parking space, such as found in typical multi-vehicle parking lots and garages. Additionally, the parking space 10 has been described as being on the right side of the vehicle V and the obstacle or vehicle V3 has been described as being on the left side of the vehicle V. Alternatively, the park assist system may be used to identify a parking space on the left side of the vehicle V and identify an obstacle or vehicle V3 on the right side of the vehicle V.
In accordance with the provisions of the patent statutes, the principle and mode of operation of this invention have been described and illustrated in its preferred embodiments. However, it must be understood that this invention may be practiced otherwise than as specifically explained and illustrated without departing from its spirit or scope.