Automatic swinging method to get a vehicle out of trouble

Abstract

A method of automatically rocking a stuck vehicle unstuck. The vehicle includes wheels, actuators for controlling rotation of the wheels, sensors for detecting a stuck state of the wheels, and a processor for executing an automatic rocking mode at the vehicle. The automatic rocking mode includes engaging an engine of the vehicle to a first gear, rotating the wheels via the actuators to produce a first motion of the vehicle in a first direction with the engine in the first gear, obtaining a traction indicator of the vehicle with the engine in the first gear, engaging the engine to a second gear when the traction indicator satisfies a traction threshold, and rotating the wheels via the actuators to produce a second motion of the vehicle in a second direction with the engine in the second gear.

Description

Technical Field

[0001] This subject matter relates to the operation of a vehicle, and more specifically, to a method for detaching a vehicle or its wheels from a ditch by automatically swaying the vehicle within the ditch. Background Technology

[0002] In various off-road operations, wheels may get stuck in ditches. Typically, when a vehicle's wheels are stuck, the other wheels have traction with the ground. Unfortunately, this traction is sometimes insufficient to pull the stuck wheel out of the ditch through direct acceleration of the vehicle. Manual application techniques for getting out of a ditch may require assistance from others or a high level of driver skill. Therefore, there is a need for an automated method that can be applied to a vehicle to remove a stuck wheel from a ditch. Summary of the Invention

[0003] In one exemplary embodiment, a method of operating a vehicle is disclosed. The method includes detecting that a wheel of the vehicle is stuck in a ditch and executing an automatic swaying mode at the vehicle. The automatic swaying mode includes engaging the vehicle's engine to a first gear via a processor, rotating the wheel to generate a first movement of the vehicle in a first direction while the engine is in the first gear, obtaining a grip index of the vehicle while the engine is in the first gear, engaging the engine to a second gear via the processor when the grip index meets a grip threshold, and rotating the wheel to generate a second movement of the vehicle in a second direction while the engine is in the second gear.

[0004] In addition to one or more features described herein, the method further includes obtaining the grip index while the engine is in second gear, and engaging the engine to first gear to rotate the wheels in a first direction when the grip index meets the grip threshold.

[0005] In addition to one or more features described herein, obtaining the grip index also includes measuring wheel slippage, wheel torque, and vehicle acceleration, and wherein the grip index satisfies at least one of the following: wheel slippage is greater than a slippage threshold and the ratio of wheel torque to vehicle acceleration is greater than a stall threshold.

[0006] In addition to one or more features described herein, the method also includes measuring the vehicle's speed and exiting the automatic sway mode when the vehicle's speed exceeds a first speed threshold.

[0007] In addition to one or more features described herein, the method also includes entering an automatic sway mode when at least one of the following is detected: the driver attempts to sway the vehicle; slippage is detected at the wheel for a selected duration; a value obtained from an image of the wheel indicates that the wheel is stuck; and a request to enter an automatic sway mode is received.

[0008] In addition to one or more features described in this article, the first gear is a drive gear and the second gear is a reverse gear.

[0009] In addition to one or more features described herein, the method also includes ramping the vehicle's throttle to the peak throttle value when the engine is in first gear, based on the current throttle position and the current vehicle motion.

[0010] In another exemplary embodiment, a system for operating a vehicle is disclosed. The system includes sensors for detecting if a wheel of the vehicle is stuck in a ditch and a processor for executing an automatic swaying mode at the vehicle. The automatic swaying mode includes engaging the vehicle's engine to a first gear, rotating the wheels to generate a first movement of the vehicle in a first direction while the engine is in the first gear, obtaining a grip index of the vehicle while the engine is in the first gear, engaging the engine to a second gear when the grip index meets a grip threshold, and rotating the wheels to generate a second movement of the vehicle in a second direction while the engine is in the second gear.

[0011] In addition to one or more features described herein, the processor is also configured to acquire the grip index when the engine is in second gear, and to engage the engine in first gear to rotate the wheels in a first direction when the grip index meets the grip threshold.

[0012] In addition to one or more features described herein, the processor is also configured to obtain a grip index by measuring wheel slippage, torque at the wheel, and vehicle acceleration, wherein the grip index satisfies a grip threshold when wheel slippage is greater than a slippage threshold and the ratio of torque at the wheel to vehicle acceleration is greater than at least one of a stall threshold.

[0013] In addition to one or more features described herein, the processor is also configured to measure the vehicle’s speed and exit the automatic sway mode when the vehicle’s speed exceeds a first speed threshold.

[0014] In addition to one or more features described herein, the processor is also configured to enter automatic sway mode when at least one of the following is detected: the driver attempts to sway the vehicle; slippage is detected at the wheel for a selected duration; a value obtained from an image of the wheel indicates that the wheel is stuck; and a request to enter automatic sway mode is received.

[0015] In addition to one or more features described in this article, the first gear is a drive gear and the second gear is a reverse gear.

[0016] In addition to one or more features described herein, the processor is also configured to ramp up the vehicle's throttle to the peak throttle value when the engine is in first gear, based on the current throttle position and the current vehicle motion.

[0017] In yet another exemplary embodiment, a vehicle is disclosed. The vehicle includes wheels, actuators for controlling wheel rotation, sensors for detecting wheel jamming, and a processor for executing an automatic swaying mode at the vehicle. The automatic swaying mode includes engaging the vehicle's engine to a first gear, rotating the wheels via the actuators to generate a first movement of the vehicle in a first direction while the engine is in the first gear, obtaining a grip index of the vehicle while the engine is in the first gear, engaging the engine to a second gear when the grip index meets a grip threshold, and rotating the wheels via the actuators to generate a second movement of the vehicle in a second direction while the engine is in the second gear.

[0018] In addition to one or more features described herein, the processor is also configured to acquire the grip index when the engine is in second gear, and to engage the engine in first gear to rotate the wheels in a first direction when the grip index meets the grip threshold.

[0019] In addition to one or more features described herein, the processor is also configured to obtain a grip index by measuring wheel slippage, torque at the wheel, and vehicle acceleration, wherein the grip index satisfies a grip threshold when wheel slippage is greater than a slippage threshold and the ratio of torque at the wheel to vehicle acceleration is greater than at least one of a stall threshold.

[0020] In addition to one or more features described herein, the processor is also configured to measure the vehicle’s speed and exit the automatic sway mode when the vehicle’s speed exceeds a first speed threshold.

[0021] In addition to one or more features described herein, the processor is also configured to enter automatic sway mode when at least one of the following is detected: the driver attempts to sway the vehicle; slippage is detected at the wheel for a selected duration; a value obtained from an image of the wheel indicates that the wheel is stuck; and a request to enter automatic sway mode is received.

[0022] In addition to one or more features described herein, the processor is also configured to ramp up the vehicle’s throttle to the peak throttle value when the engine is in first gear, based on the current throttle position and the current vehicle motion.

[0023] The above-described features and advantages, as well as other features and advantages, of this disclosure will become apparent when taken in conjunction with the accompanying drawings and the following detailed description. Attached Figure Description

[0024] Other features, advantages, and details appear by way of example only in the following detailed description, which is described in detail with reference to the accompanying drawings, in which:

[0025] Figure 1 A vehicle according to an exemplary embodiment is shown;

[0026] Figure 2 It is a perspective view of the rear of the vehicle;

[0027] Figure 3A The vehicle is shown in the first position, with the right rear wheel in the ditch and located at or towards the front surface of the ditch;

[0028] Figure 3B The vehicle is shown in a second position, with its wheels on the rear surface of the ditch;

[0029] Figure 3C This shows that the vehicle has returned from the second position to the first position in the ditch;

[0030] Figure 3D This indicates that the vehicle has left the ditch;

[0031] Figure 4 This is a flowchart of a method for entering the automatic rocking mode of a vehicle; and

[0032] Figure 5A and 5B A flowchart is shown for a method of operating a vehicle in automatic rocking mode. Detailed Implementation

[0033] The following description is exemplary in nature only and is not intended to limit this disclosure, its application, or use. It should be understood that throughout the drawings, corresponding reference numerals denote the same or corresponding parts and features.

[0034] According to an exemplary embodiment, Figure 1 Vehicle 10 is shown. In various embodiments, vehicle 10 is an autonomous vehicle. The autonomous vehicle may include a trajectory planning system depicted at 100. Typically, trajectory planning system 100 determines a trajectory plan for autonomous driving of vehicle 10. Vehicle 10 typically includes a chassis 12, a body 14, front wheels 16, and rear wheels 18. Body 14 is disposed on chassis 12 and substantially surrounds the components of vehicle 10. Body 14 and chassis 12 may together form a frame. Front wheels 16 and rear wheels 18 are each rotatably coupled to chassis 12 near a corresponding corner of body 14.

[0035] In various embodiments, the trajectory planning system 100 is incorporated into the autonomous vehicle. The autonomous vehicle is, for example, a vehicle automatically controlled to transport passengers from one location to another. The autonomous vehicle is depicted as a passenger car in the illustrated embodiment, but it should be understood that any other vehicle, including motorcycles, trucks, SUVs, RVs, etc., may also be used. At various levels, the autonomous vehicle can assist the driver in a variety of ways, such as by providing warning signals indicating impending risk situations, enhancing the driver's situational awareness by predicting the movement of other agents that warn of potential collisions, etc. The autonomous vehicle has different levels of intervention or control over the vehicle, from coupled assisted vehicle control to complete control of all vehicle functions. The autonomous vehicle can be any of a Level 1 to Level 5 system. A Level 1 system includes driver assistance and performs a single autonomous task at a time, such as steering or braking. A Level 1 system may include cruise control and lane detection. A Level 2 system includes partial driving automation. Such a vehicle can control both steering and speed, but the driver must be prepared to take over in an emergency. A Level 3 system is a conditional driving automation system that includes environmental detection capabilities. Such vehicles can perform most driving tasks, but still require human overdrive. Level 4, indicating "high automation," refers to the driving mode-specific performance of the automated driving system for all aspects of dynamic driving tasks, even if the human driver does not appropriately respond to intervention requests. Level 5, indicating "full automation," refers to the full-time performance of the automated driving system for all aspects of dynamic driving tasks under all road and environmental conditions that can be managed by a human driver.

[0036] As shown, an autonomous vehicle typically includes a propulsion system 20, a transmission system 22, a steering system 24, a braking system 26, a sensor system 28, an actuator system 30, and a controller 34. In various embodiments, the propulsion system 20 may include an internal combustion engine, an electric motor such as a traction motor, and / or a fuel cell propulsion system. The transmission system 22 is configured to transmit power from the propulsion system 20 to the front wheels 16 and the rear wheels 18 according to a selectable speed ratio. According to various embodiments, the transmission system 22 may include a stepped automatic transmission, a continuously variable transmission (CVT), or other suitable transmission. The braking system 26 is configured to provide braking torque to the front wheels 16 and the rear wheels 18. In various embodiments, the braking system 26 may include friction brakes, brake-by-wire brakes, regenerative braking systems (such as electric motors), and / or other suitable braking systems. The steering system 24 influences the position of the front wheels 16 and the rear wheels 18.

[0037] Sensor system 28 includes one or more sensing devices 40a-40n that sense observable conditions of the autonomous vehicle's external and / or internal environment. Sensing devices 40a-40n may include, but are not limited to, radar, lidar, global positioning systems, optical cameras, thermal cameras, ultrasonic sensors, and / or other sensors. Sensing devices 40a-40n acquire measurements or data relating to various objects or agents 50 within the vehicle's environment. Such agents 50 may be, but are not limited to, other vehicles, pedestrians, bicycles, motorcycles, etc., as well as non-moving objects. Sensing devices 40a-40n may also acquire traffic data, such as information about traffic signals and signs.

[0038] The sensor system 28 also includes internal sensing devices 41 that monitor various parts of the vehicle. Internal sensing devices 41 may include cameras, digital cameras, or lidar pointed at the wheels of the vehicle to obtain information about the state of the wheels (i.e., whether a wheel is stuck in a ditch). Internal sensing devices 41 may also include speedometers for measuring vehicle speed, accelerometers for measuring vehicle acceleration, torque sensors for measuring torque at the wheels, etc.

[0039] The actuator system 30 includes one or more actuator devices 42a-42n that control one or more vehicle features, such as, but not limited to, the propulsion system 20, the transmission system 22, the steering system 24, and the braking system 26. In various embodiments, vehicle features may also include interior and / or exterior vehicle features, such as, but not limited to, doors, trunk, and cabin features, such as ventilation, music, lighting, etc. (not numbered).

[0040] The controller 34 includes a processor 44 and a computer-readable storage device or medium 46. The processor 44 may be any custom or commercially available processor, central processing unit (CPU), graphics processing unit (GPU), auxiliary processor among several processors associated with the controller 34, semiconductor-based microprocessor (in the form of a microchip or chipset), macroprocessor, any combination thereof, or any device typically used for executing instructions. The computer-readable storage device or medium 46 may include volatile and non-volatile storage, such as read-only memory (ROM), random access memory (RAM), and keep-alive memory (KAM). KAM is persistent or non-volatile memory that can be used to store various operational variables when the processor 44 is powered off. The computer-readable storage device or medium 46 may be implemented using any of many known memory devices, such as PROM (programmable read-only memory), EPROM (electrical PROM), EEPROM (electrically erasable PROM), flash memory, or any other electrical, magnetic, optical, or combined memory device capable of storing data, some of which represents executable instructions used by the controller 34 in controlling an autonomous vehicle.

[0041] The instructions may include one or more separate programs, each comprising an ordered list of executable instructions for implementing logical functions. When executed by processor 44, the instructions receive and process signals from sensor system 28, execute logic, calculations, methods, and / or algorithms for automatically controlling components of the autonomous vehicle, and generate control signals to actuator system 30 to automatically control components of the autonomous vehicle based on logic, calculations, methods, and / or algorithms. The instructions may also execute logic, calculations, methods, and / or algorithms for operating the vehicle in an automatic swaying mode using methods disclosed herein to perform actions to move the vehicle (or at least one of its wheels) out of a ditch.

[0042] It should be understood that vehicle 10 does not need to be an autonomous vehicle, but can be a vehicle with a controller for controlling various operations, such as measuring vehicle parameters, automatically shifting gears based on the vehicle's state, controlling the throttle, and other operations disclosed herein.

[0043] Figure 2 This is a perspective view 200 of the rear end of vehicle 10. The right rear wheel 202 is stuck in a ditch 204. The ditch 204 can be a rut, hole, pothole, pit, depression, or depression in the mud. The relative lack of friction between the wheel and the ditch prevents the vehicle from leaving the ditch. The presence of mud in the ditch can further reduce the friction between the wheel and the ditch.

[0044] Figures 3A-3D A method for exiting a ditch is illustrated. The ditch 204 has a front surface 302 and a rear surface 304. The two surfaces are defined relative to the direction of forward movement of the vehicle. Both the front surface 302 and the rear surface 304 are non-horizontal or inclined surfaces. Figure 3A The vehicle 10 is shown in a first position, with the right rear wheel 202 in a ditch and located at or toward the front surface 302 of the ditch. As a first action of the automatic rocking mode, the vehicle 10 is put into reverse to rotate the wheel, causing the vehicle to move toward the rear surface 304 of the ditch.

[0045] Figure 3B The vehicle is shown in the second position, with its wheels positioned at the rear surface 304 of the ditch. As a result of performing the first action when the vehicle 10 was in the first position, the vehicle discovers itself in the second position. Figure 3A With vehicle 10 in the second position and the wheels still stuck in ditch 204, a second action is taken, wherein the vehicle is put into forward gear to rotate the wheels, causing the vehicle to move toward front surface 302.

[0046] Figure 3CThis shows that the vehicle has returned from the second position to the first position in the ditch. As a result of performing the second action while the vehicle was in the second position, the vehicle again finds itself in the first position. Figure 3B Upon returning to the first position, the vehicle exhibits an additional forward motion that it did not have when initially in the first position (i.e., Figure 3A ).

[0047] Figure 3D The diagram shows the vehicle has left the ditch. The forward motion of the vehicle as it returns to the first position allows it to climb out of the ditch. If the vehicle's motion is insufficient to allow it to leave the ditch, the method can be repeated and continued until the vehicle is able to leave through the front or rear of the ditch.

[0048] Figure 4 This is a flowchart 400 of a method for entering an automatic rocking mode for a vehicle. The method begins at box 402. The method includes checking various conditions of the vehicle, as shown in boxes 404, 406, 408, and 412. In box 404, one or more sensors (such as an accelerometer and / or an inertial measurement unit) detect motion in the vehicle. If it is determined based on this motion that the driver is attempting to rock the vehicle, the method proceeds to box 410. In box 410, the customer or driver is prompted to enter automatic rocking mode. From box 410, the method proceeds to box 414. Returning to box 404, if it is determined that there is no attempt to rock the vehicle, the method returns to box 402.

[0049] In box 406, a measurement of wheel slippage is obtained. If the measurement indicates that wheel slippage occurred within a selected duration, the method proceeds to box 410. In box 410, the customer or driver is prompted to enter automatic rocking mode. From box 410, the method proceeds to box 414. Returning to box 406, if it is determined that no wheel slippage exists, the method returns to box 402.

[0050] In box 408, an image of the vehicle's wheels is obtained and viewed. This image can be a camera image, a LiDAR image, etc. If the image determines that the wheel is stuck in the ditch, the method proceeds to box 410. In box 410, the customer or driver is prompted to enter automatic rocking mode. From box 410, the method proceeds to box 414. Returning to box 408, if the image determines that the wheel is not stuck in the ditch, the method returns to box 402.

[0051] In box 412, the driver can manually decide to enter automatic rocking mode. From box 412, the method proceeds to box 414. In box 414, the controller checks whether the drive has entered automatic rocking mode. If the driver has not yet entered automatic rocking mode, the method returns to box 402. Otherwise, the method proceeds to box 416. In box 416, automatic rocking mode is entered. In box 418, the driver is instructed to place the vehicle in neutral, with the throttle at full throttle or 100%.

[0052] In box 420, the controller checks whether the driver has followed the instruction to put the vehicle into automatic rocking mode. If the vehicle is not in neutral, the condition "throttle > 0%" is not met (or the throttle is not higher than the selected threshold percentage), and the method returns to box 418. Otherwise (i.e., if the vehicle is in neutral, the throttle is > 0 or higher than the selected threshold percentage), the method proceeds to box 502. Figure 5A ).

[0053] Figure 5A and 5B A flowchart 500 illustrates a method for operating a vehicle in automatic rocking mode. In block 502, the controller places the vehicle in drive (i.e., engages the engine in drive). This maneuver can be warned to the driver using an audible signal (e.g., a bell). In block 504, the controller ramps the vehicle's throttle or acceleration to a peak target throttle value to move the vehicle in a first direction (forward). The peak target throttle value can be a pre-selected value and can be adjusted based on an assessment of power demand, as discussed herein. The rate of throttle ramping can be based on the current vehicle motion and the current throttle position.

[0054] In block 506, the controller performs calculations to determine the effectiveness of the vehicle's swaying mode in drive. Appropriate parameters, such as wheel slippage, wheel torque, and vehicle acceleration, are detected. These parameters are used to determine one or more grip metrics indicating whether the vehicle is able to gain traction. Grip metrics can be wheel slippage and / or vehicle motion stall. Wheel slippage can be determined by determining the rotational rate of the stuck wheel compared to the rotational rates of other wheels. Vehicle motion stall can be a value determined by the ratio of wheel torque (the amount of torque applied to the wheel) to vehicle acceleration (i.e., the acceleration of the vehicle). At constant wheel torque, the ratio increases as vehicle motion decreases. For example, a high vehicle motion stall value occurs when the torque applied to the wheel causes the vehicle to accelerate forward with little or no forward acceleration. The grip metrics are compared to grip thresholds to determine the vehicle's state and thus determine subsequent steps. For example, if wheel slippage is greater than the slippage threshold or motion stall is detected (i.e., ratio > stall threshold), the vehicle is considered no longer effectively moving forward, and the method proceeds to block 520. However, if the wheel slippage is less than the slippage threshold and there is no stall detection (i.e., ratio <= stall threshold), the vehicle still moves forward effectively and the method proceeds to box 508.

[0055] In box 508, the vehicle's speed is compared to a first threshold speed. The first threshold speed indicates the vehicle's expected speed once the wheels leave the ditch. If the speed is greater than the first threshold speed, the vehicle is considered to have successfully left the ditch, and the method proceeds to box 540.

[0056] In box 540, the controller confirms that the vehicle is not stuck and sends a signal to the driver to suggest that the driver exit the rocking mode by executing an exit sequence. The exit sequence can be a sequence of pressing a single button or a pre-existing sequence of buttons. The method then proceeds to box 542. In box 542, if the controller receives a signal indicating that the driver has executed the exit sequence, the method proceeds to box 546. Otherwise, the method proceeds to box 544. In box 544, the vehicle speed is compared to a second speed threshold. The second speed threshold can be greater than a first speed threshold. The second speed threshold can be a speed that the driver might reach when accelerating on a road with traction. If, in box 544, the speed is less than the second speed threshold, the method returns to box 540. However, if, in box 544, the vehicle speed is greater than the second speed threshold, the method proceeds to box 546. In box 546, the controller exits the rocking mode. The method then proceeds to box 548, where the method terminates.

[0057] Returning to box 508, if the vehicle speed is less than the first speed threshold, the vehicle is considered still stuck, and the method proceeds to box 510.

[0058] In box 510, the controller determines whether the driver has executed an exit sequence. If the driver has executed an exit sequence, the method proceeds to box 546. Otherwise (i.e., the driver has not yet executed an exit sequence), the method proceeds to box 512. In box 512, the throttle is checked. If the throttle is positive (greater than zero), the method returns to box 504, where the throttle adjustment continues. If the throttle is not zero in box 512, the method proceeds to box 514. In box 514, the controller stops applying the throttle and suggests that the driver apply the throttle to maintain the automatic rocking mode.

[0059] In box 516, the throttle is checked again to see if the driver is still keeping the throttle open. If the throttle is less than zero, the method returns to box 504. Otherwise, the method proceeds to box 542.

[0060] Now turning to box 520, the controller puts the vehicle in reverse (i.e., engages the engine in reverse). This maneuver can be warned to the driver using an audible signal (such as a bell). In box 524, the controller ramps the vehicle's throttle or acceleration to a peak target throttle value to move the vehicle in the second direction (rearward). The rate of throttle ramp can be based on the current vehicle motion and the current throttle position.

[0061] In box 526, the controller determines the validity of the sway mode when the vehicle is in reverse. Wheel slippage, wheel torque, and vehicle acceleration are detected to determine grip metrics. If wheel slippage exceeds a slippage threshold or a motion stall is detected, the method proceeds to box 528. In box 528, the peak target throttle is increased by a selected amount. From box 528, the method returns to box 502. Returning to box 526, if wheel slippage is less than the slippage threshold and no stall is detected, the method proceeds to box 530.

[0062] In box 530, the vehicle's speed is compared to a first threshold speed. If the vehicle speed is greater than the first speed threshold, the vehicle is considered to have successfully left the ditch, and the method proceeds to box 540. Otherwise, the method proceeds to box 532.

[0063] In box 532, the controller determines whether the driver has executed an exit sequence. If the driver has executed an exit sequence, the method proceeds to box 546. However, if the driver has not executed an exit sequence, the method proceeds to box 534. In box 534, the throttle is checked. If the throttle is positive (greater than zero), the method returns to box 524, where the throttle adjustment continues. If the throttle is not zero in box 534, the method proceeds to box 536. In box 536, the controller stops applying the throttle and suggests that the driver apply the throttle to maintain the automatic rocking mode.

[0064] In box 538, the throttle valve is checked again. If the throttle is less than zero, the method returns to box 524. Otherwise, the method proceeds to box 542.

[0065] Although the automatic rocking mode has been described in a specific order (i.e., the vehicle is first put into drive and then into reverse), in other embodiments, the first gear may be reverse and the second gear may be drive.

[0066] The terms “a” and “an” do not indicate a limitation of quantity, but rather that at least one of the referenced items is present. Unless the context clearly indicates otherwise, the term “or” means “and / or”. Throughout the specification, the reference to “aspect” means that a particular element described in connection with that aspect (e.g., a feature, structure, step, or characteristic) is included in at least one aspect described herein and may or may not be present in other aspects. Furthermore, it should be understood that the described elements may be combined in any suitable manner in the aspects.

[0067] When an element, such as a layer, film, region, or substrate, is referred to as being “on” another element, it can be directly on the other element, or there may be intermediate elements present. Conversely, when an element is referred to as being “directly” on another element, there are no intermediate elements present.

[0068] Unless otherwise stated herein, all test standards are the most recent standards in force up to the date of filing of this application, or, if priority is claimed, the date of filing of the earliest priority application in which a test standard appears.

[0069] Unless otherwise defined, the technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains.

[0070] While the foregoing disclosure has been described with reference to exemplary embodiments, those skilled in the art will understand that various changes can be made and elements can be substituted with equivalents without departing from its scope. Furthermore, many modifications can be made to adapt particular situations or materials to the teachings of this disclosure without departing from the basic scope of this disclosure. Therefore, it is intended that this disclosure be limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

[0071] List of reference numerals Figure 4 5A, 5BY - Yes; N - No.

Claims

1. A method of operating a vehicle, comprising: The vehicle being inspected had one wheel stuck in a ditch; An automatic swaying mode is executed at the vehicle, wherein the automatic swaying mode includes: The processor engages the vehicle's engine in first gear; With the engine in first gear, the wheels are rotated to generate the first motion of the vehicle in the first direction; The vehicle's grip index is obtained when the engine is in first gear; When the grip index meets the grip threshold, the processor engages the engine in second gear; and With the engine in second gear, the wheels are rotated to generate a second movement of the vehicle in a second direction.

2. The method of claim 1, further comprising obtaining the grip index while the engine is in second gear, and engaging the engine to first gear to rotate the wheels in a first direction when the grip index meets the grip threshold.

3. The method of claim 1, wherein obtaining the grip index further comprises measuring wheel slippage, torque at the wheel, and vehicle acceleration, and wherein the grip index satisfies the grip threshold when at least one of the following occurs: (i) wheel slippage is greater than a slippage threshold; and (ii) the ratio of torque at the wheel to vehicle acceleration is greater than a stall threshold.

4. The method of claim 1 further includes measuring the speed of the vehicle, and exiting the automatic rocking mode when the speed of the vehicle is greater than a first speed threshold.

5. The method according to claim 1 further includes, based on the current throttle position and the current vehicle movement, when the engine is in first gear, increasing the vehicle's throttle to the peak throttle value.

6. A system for operating a vehicle, comprising: Sensors are used to detect if a vehicle's wheels are stuck in a ditch; A processor is configured to execute an automatic swaying mode at the vehicle, wherein the automatic swaying mode includes: Engage the vehicle's engine in first gear; With the engine in first gear, the wheels are rotated to generate the first motion of the vehicle in the first direction; The vehicle's grip index is obtained when the engine is in first gear; When the grip index meets the grip threshold, engage the engine in second gear; and With the engine in second gear, the wheels are rotated to generate a second movement of the vehicle in a second direction.

7. The system of claim 6, wherein the processor is further configured to obtain the grip index when the engine is in second gear, and to engage the engine in first gear to rotate the wheels in a first direction when the grip index meets the grip threshold.

8. The system of claim 6, wherein the processor is further configured to obtain the grip index by measuring wheel slippage, torque at the wheel, and vehicle acceleration, and wherein the grip index satisfies the grip threshold when at least one of the following occurs: (i) wheel slippage is greater than a slippage threshold; and (ii) the ratio of torque at the wheel to vehicle acceleration is greater than a stall threshold.

9. The system of claim 6, wherein the processor is further configured to measure the speed of the vehicle and exit the automatic sway mode when the speed of the vehicle is greater than a first speed threshold.

10. The system of claim 6, wherein the processor is further configured to ramp up the vehicle's throttle to a peak throttle value when the engine is in first gear, based on the current throttle position and the current vehicle motion.

Images