阅读说明：本技术 基于所识别的道路不平整处调整操作参数 (Adjusting operating parameters based on identified road irregularities ) 是由 约翰·埃里克·罗林杰 泰勒·凯利 斯科特·S·汤普森 于 2021-04-28 设计创作，主要内容包括：本公开提供“基于所识别的道路不平整处调整操作参数”。提供了用于改善车辆速度测量值的方法和系统。车辆可检测道路不平整处对其前轮和后轮的撞击,并且可基于其轴距和所述两次撞击之间经过的时间来计算瞬时车辆速度。然后,可使用该瞬时车辆速度来计算一个或多个校正因素,所述校正因素可用于校正常规获取的车辆速度测量值、此类测量值所依据的所述车辆的操作参数(诸如车轮大小或主减速比)或两者。(The present disclosure provides for "adjusting operating parameters based on identified road irregularities". Methods and systems for improving vehicle speed measurements are provided. The vehicle may detect impacts to its front and rear wheels at road irregularities and may calculate the instantaneous vehicle speed based on its wheelbase and the time elapsed between the impacts. This instantaneous vehicle speed may then be used to calculate one or more correction factors that may be used to correct conventionally acquired vehicle speed measurements, operating parameters of the vehicle (such as wheel size or final drive ratio) from which such measurements are based, or both.)

1. A method, comprising:

detecting, for a vehicle in motion, a first impact on a front suspension and a second impact on a rear suspension to identify a bump;

when the jog is identified, deriving an instantaneous vehicle speed based on a first operating parameter of the vehicle; and

a correction factor for a second operating parameter of the vehicle is calculated based on the instantaneous vehicle speed.

2. The method of claim 1, wherein the first operating parameter of the vehicle is a wheelbase of the vehicle.

3. The method of claim 1, wherein the second operating parameter of the vehicle is one of: wheel size, final drive ratio, and tire pressure.

4. The method of claim 1, further comprising:

subsequent vehicle speed measurements are corrected according to a formula based on the second operating parameter and the correction factor.

5. The method of claim 1, wherein a criterion for detecting at least one of the first impact and the second impact is that a vertical acceleration exceeds a predetermined threshold.

6. The method of claim 1, wherein the criterion for identifying the asperities is that a time duration elapsed between the first impact and the second impact falls within a predetermined range.

7. The method of claim 6, wherein the predetermined range is a function of a vehicle speed measurement.

8. The method of claim 6, wherein the predetermined range is a function of a wheelbase of the vehicle.

9. The method as claimed in claim 1, wherein a criterion for identifying the asperities is that a travel direction of the vehicle remains within a predetermined range between a time of the first impact and a time of the second impact.

10. The method of claim 1, wherein a criterion for identifying the asperities is that a longitudinal acceleration of the vehicle does not exceed a predetermined threshold between a time of the first impact and a time of the second impact.

11. The method of claim 1, wherein a criterion for identifying the asperities is that braking of the vehicle does not exceed a predetermined threshold between a time of the first impact and a time of the second impact.

12. A vehicle speed recalibration system for a vehicle having a set of front wheels and a set of rear wheels, the vehicle speed recalibration system comprising:

a mechanism for detecting a first impact, wherein at least one of the front wheels has passed over a bump;

a mechanism for detecting a second impact, wherein at least one of the rear wheels has passed over a bump;

a timer mechanism to determine a duration of time elapsed between a first time at which the first impact was detected and a second time at which the second impact was detected; and

one or more processors to execute instructions stored in non-transitory memory that cause the one or more processors to perform operations comprising:

calculating an instantaneous vehicle speed from the wheelbase of the vehicle and the elapsed duration; and

subsequent vehicle speed measurements are updated based on the instantaneous vehicle speed.

13. The vehicle speed recalibration system of claim 12, wherein a criterion for detecting at least one of the first impact and the second impact is that a vertical acceleration exceeds a predetermined threshold.

14. The vehicle speed recalibration system of claim 12, the operations further comprising:

updating a value of an operating parameter selected from a wheel size or a final reduction ratio,

wherein the subsequent vehicle speed measurement is a function of an additional operating parameter.

15. The vehicle speed recalibration system of claim 12, the operations further comprising:

aborting the operation in response to detecting any of the following between the first time and the second time: a change in a direction of travel of the vehicle exceeding a predetermined threshold; the longitudinal acceleration of the vehicle exceeds a predetermined threshold; or the braking of the vehicle exceeds a predetermined threshold.

Technical Field

The present description relates generally to methods and systems for accounting for changes in operating parameters of a vehicle.

Background

The measurement of vehicle speed may assist the driver (and the mechanism providing automatic cruise control) in assessing the speed of the vehicle, which in turn may help in cautious driving and compliance with various relevant laws and regulations. The vehicle speed may be determined by measuring other parameters of the vehicle that may be related to the vehicle speed and using the related parameters to derive a vehicle speed measurement. For example, wheel size or final drive ratio may be used along with revolutions per minute to derive a vehicle speed measurement.

However, vehicles may sometimes be retrofitted in a manner that affects their operating parameters. Replacing a tire may change the wheel size (such as by changing the size of the vehicle tire itself, or by changing the air pressure of the tire). Similarly, changing the final reduction ratio may change the relationship between the number of revolutions of the vehicle engine and the number of revolutions of the wheels. Furthermore, due to the general tolerances on the measured values of the operating parameters (such as wheel speed sensors or output shaft speed sensors), the various parameters may not be as accurate as possible. These factors can lead to inaccuracies in the vehicle speed measurement, which can then be reported to the driver and the various electronic controllers in the vehicle that may use such information.

By detecting road irregularities (e.g., bumps) with the front and rear wheels (or front and rear suspensions), technical results of correcting subsequent vehicle speed measurements or correcting basic operating parameters, or both, may be provided. For example, detecting an impact to the front wheels of the vehicle due to bumps or other road irregularities, then detecting a subsequent impact to the rear wheels of the vehicle, and determining the elapsed time between impacts may allow the instantaneous vehicle speed to be calculated based on the wheelbase of the vehicle and the elapsed time. This calculated instantaneous vehicle speed may then be used to determine a correction factor for correcting subsequent vehicle speed measurements.

Disclosure of Invention

In recognition of the above-mentioned problems, various mechanisms and methods disclosed herein have been developed. These mechanisms and methods may: detecting when a front wheel or front suspension of the vehicle hits a road irregularity (e.g., a bump); detecting when a rear wheel or rear suspension of the vehicle hits a road irregularity; identifying the occurrence of road irregularities based on the two impacts; determining the time elapsed between two impacts; and calculating an instantaneous vehicle speed based on the wheelbase of the vehicle and the elapsed time. The mechanisms and methods may then calculate a correction factor based on the instantaneous vehicle speed measurement and the conventionally acquired vehicle speed measurement, and may correct subsequent conventionally acquired vehicle speed measurements based on the correction factor. Thus, the mechanisms and methods disclosed herein may advantageously allow for more accurate measurements of vehicle speed for use by a vehicle operator and/or an automatic vehicle controller (e.g., a cruise control system).

The above advantages and other advantages and features of the present description will become readily apparent from the following detailed description when taken alone or in conjunction with the accompanying drawings.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. This is not intended to identify key or essential features of the claimed subject matter, the scope of which is defined solely by the claims that follow the detailed description. Additionally, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

Drawings

FIG. 1A shows a scene where a vehicle is traversing a road irregularity;

1B-1D show timelines associated with a vehicle traversing road irregularities under various conditions;

FIG. 2 shows a schematic top view of a vehicle incorporating a mechanism for improving vehicle speed measurements according to one or more embodiments of the present disclosure;

FIG. 3 illustrates an exemplary method of identifying road irregularities and correcting operating parameters of a vehicle propulsion system;

FIG. 4 illustrates an exemplary method of calculating an instantaneous vehicle speed based on traversed road irregularities and correcting a vehicle speed measurement of a vehicle propulsion system; and is

FIG. 5 depicts a vehicle propulsion system incorporating a mechanism for improving wheel speed measurements.

Detailed Description

The following description relates to systems and methods for calculating instantaneous vehicle speed based on traversed road irregularities and correcting vehicle speed measurements of a vehicle propulsion system. As depicted and discussed with respect to fig. 1A and 2, the vehicle may traverse and identify road irregularities (e.g., bumps). As depicted and discussed with respect to fig. 1A-4, the vehicle may calculate an instantaneous vehicle speed based on the impact associated with the irregularity, and the instantaneous vehicle speed may be used to correct an operating parameter of the vehicle (such as wheel size or final drive ratio) and/or may correct a subsequent conventionally acquired vehicle speed measurement. As depicted and discussed with respect to fig. 2 and 5, various vehicle configurations may employ these mechanisms and methods.

FIG. 1A shows a scene 100 in which a vehicle 110 is traversing a road 120 having road irregularities 130. The vehicle 110 may include one or more front wheels 112 and one or more rear wheels 114. The wheelbase 118 may be the distance between the centers of the front and rear wheels 112, 114 (e.g., at a neutral steering position of the vehicle 100 where the wheelbase is the same on the left and right sides).

Irregularities 130 are depicted as upwardly extending protrusions. However, in various embodiments, the irregularities 130 may be downwardly extending dimples. Furthermore, the irregularities 130 may be engineered features of the road (such as speed bumps), or may be non-engineered features of the road (such as potholes or rocks or other debris). In various embodiments, the irregularities 130 may be any kind of bump (bump) that causes an impact to the wheels of the vehicle 110. Because vehicle 110 may encounter and traverse a wide variety of irregularities and bumps during typical use, vehicle 110 may have many opportunities to benefit from the advantageous mechanisms and methods disclosed herein.

At a first time 101, the vehicle 110 has not yet reached the irregularity 130, while at a second time 102, the front wheels 112 of the vehicle 110 are crossing the irregularity 130. When the front wheels 112 of the vehicle 110 reach and impact the irregularities 130, the front wheels may be impacted, which, as discussed herein, may be detected by the vehicle 110. Thereafter, at a third time 103, the rear wheels 114 of the vehicle 110 are crossing an irregularity 130, which the vehicle 110 may also detect. At a fourth time 104, the vehicle 110 has completed traversing the irregularity 130.

In the scenario 100, the vehicle 110 crosses the road 120 at a substantially constant speed. The vehicle 110 may travel at a relatively low vehicle speed, such as a speed below about 25 mph. For an impact detection algorithm that operates at a sampling rate of approximately 10 milliseconds (ms), the data collected about an impact at relatively low vehicle speeds may advantageously be very accurate compared to data collected from, for example, wheel speed sensors or drive axle sensors. In some embodiments, the data collected as disclosed herein may be 2 to 10 times accurate. Thus, such collected data may be advantageously independent of some maximum "noise" factor (such as wheel size or tire size and/or final drive ratio) that may lead to inaccurate vehicle speed sensing.

The vehicle 110 may detect the impact of the irregularity 130 in various ways. In some embodiments, vehicle 110 may detect a first impact to a front suspension of vehicle 110 associated with front wheels 112 and/or may detect a second impact to a rear suspension of vehicle 110 associated with rear wheels 114. For some embodiments, vehicle 110 may detect individual impacts to the left and right wheels of front wheels 112, and/or may detect individual impacts to the left and right wheels of rear wheels 114. Then, the vehicle 110 may recognize that it has undergone the asperity by having detected the first impact and the subsequent second impact.

In some embodiments, the vehicle 110 may use one or more accelerometers to detect the impact. For example, in some embodiments, vehicle 110 may use a vertical accelerometer mounted to, connected to, or otherwise coupled to a front suspension of vehicle 110 or a rear suspension of vehicle 110. For some embodiments, the vehicle 110 may use vertical accelerometers mounted to, connected to, or otherwise coupled to one or more of the front wheels 112 and/or the rear wheels 114. In some embodiments, vertical accelerometer data (e.g., the change in road surface height of the road 120 in the Z direction perpendicular to the horizontal plane of the vehicle 110) may be acquired by: processing data from one or more longitudinal accelerometers and one or more transverse accelerometers; calculating an average pitch and average roll associated with the road 120; removing the average pitch and roll from the data; removing transient longitudinal and lateral accelerations from the motive force change; and removing the divert from the data.

In various embodiments, where it has been identified that a bump has been experienced, vehicle 110 may derive an instantaneous vehicle speed based on wheel base 118 (or another operating parameter of the vehicle). The vehicle 110 may derive the instantaneous vehicle speed by dividing the wheel base 118 by the amount of time it takes the vehicle 110 to traverse that length (e.g., the amount of time between the first and second impacts).

In some embodiments, the vehicle 110 may have a timer that may be initialized at start-up. When vehicle 110 detects a first impact, it may start a timer, and when vehicle 110 detects a second impact, it may stop the timer. For some embodiments, the vehicle 110 may count a number of samples (obtained at the sampling rate of its impact detection algorithm) between the first impact and the second impact.

The instantaneous vehicle speed may then be used to calculate (and use) one or more correction factors. For example, in some embodiments, the vehicle 110 may calculate a correction factor to apply directly to a conventionally acquired vehicle speed measurement (e.g., a vehicle speed measurement based on a dedicated sensor). Once the instantaneous vehicle speed as discussed herein is derived, the vehicle 110 may calculate a correction factor, which may be multiplied by a conventionally obtained vehicle speed measurement to arrive at the instantaneous vehicle speed as disclosed herein. The vehicle 110 may then correct the subsequent conventionally acquired vehicle speed measurement by multiplying it by the correction factor.

For some embodiments, vehicle 110 may calculate a correction factor to apply indirectly to a conventionally obtained vehicle speed measurement by directly applying to an operating parameter (such as wheel size, final drive ratio, or tire air pressure) from which the conventionally measured vehicle speed is based. For example, vehicle 110 may obtain its regular vehicle speed measurement based on assumed values of basic operating parameters: the vehicle 110 may make assumptions about wheel size to calculate a vehicle speed measurement according to a formula based on wheel speed, or make assumptions about final drive ratio to calculate a vehicle speed measurement according to a formula based on drive axle speed.

Once the instantaneous vehicle speed as discussed herein is derived, the vehicle 110 may calculate a correction factor by which the assumed value of the base operating parameter may be multiplied so that the vehicle speed measurement based on the assumed parameter will match the instantaneous vehicle speed. The calculation will depend on the relationship between the operating parameters and the conventionally acquired vehicle speed measurements. The vehicle 110 may then correct the subsequent conventionally acquired vehicle speed measurement by multiplying the assumed value of the base operating parameter by the correction factor and then calculating the vehicle speed measurement based on the corrected value of the base operating parameter.

1B-1D show timelines associated with a vehicle traversing road irregularities under various conditions. A first timeline 151 depicts desired data collection conditions (which may be substantially similar to the data collection conditions discussed above with respect to fig. 1A). However, for various embodiments, the crash detection algorithm of the vehicle 110 may determine that an undesirable data collection condition exists, and may subsequently abort execution of the algorithm in progress.

For example, after a first impact is detected, if a second impact is not detected within a predetermined time range, which may be a function of the measured vehicle speed and/or wheel base 118 (as depicted in the second timeline 152), the timer may reset (and the impact detection algorithm will begin looking for another first impact). Alternatively, after a first impact is detected, if a second impact is detected before the beginning of the predetermined time range (as depicted in the third timeline 153), the timer may be reset (and the impact detection algorithm will begin looking for another first impact). Thus, one criterion for identifying that the vehicle 110 has encountered irregularities or bumps may be that the time duration elapsed between the first impact and the second impact falls within a predetermined range.

For embodiments in which the vehicle 110 is capable of detecting separate impacts to the left and right wheels, another criterion to identify that the vehicle 110 has encountered irregularities or bumps may be that one or more wheels do not detect an impact detected by another wheel on the same end of the vehicle 110. For example, if vehicle 110 detects an impact associated with one of front wheels 112 but does not detect an impact associated with the other front wheel 112, or if vehicle 110 detects an impact associated with one of rear wheels 114 but does not detect an impact associated with the other rear wheel 114 (as depicted in fourth time line 154), vehicle 110 may be unable to recognize that it has encountered irregularities or bumps for purposes of its impact detection algorithm. Alternatively, the vehicle 110 may recognize that it has encountered irregularities or bumps, but may take into account data relating to the steering condition to correct the condition, such as by changing the wheelbase used for the calculation based on the known steering angle (as depicted in the fifth timeline 155). For example, if the first impact is to a wheel on the side of the vehicle opposite the side the vehicle is turning, the vehicle may increase the used wheelbase value, or if the first impact is to a wheel on the same side of the vehicle as the side the vehicle is turning, the vehicle may decrease the used wheelbase value.

In various embodiments, other criteria for identifying irregularities or bumps may relate to the consistency of the trajectory of vehicle 110 between the time of a first impact and the time of a second impact. For example, in some embodiments, the criteria for identifying irregularities or bumps may be that the direction of travel of the vehicle remains within a predetermined range between the first impact and the second impact (e.g., the vehicle does not significantly turn, unlike the scenario depicted in sixth timeline 156). For some embodiments, the criteria may be that the acceleration of the vehicle does not exceed a predetermined threshold between the first and second impacts (e.g., the vehicle is not accelerating significantly, unlike the scenario depicted in the seventh timeline 157), and/or that the braking of the vehicle does not exceed a predetermined threshold between the first and second impacts (e.g., the vehicle is not decelerating significantly, unlike the scenario depicted in the eighth timeline 158). For example, the predetermined thresholds for acceleration and braking may be set relatively close to zero, such that they may not contribute as significantly to the instantaneous speed calculation as the conventionally acquired vehicle speed measurement may cause. In various embodiments, the acceleration threshold and the braking threshold may be predetermined non-zero values.

In various embodiments, identification of irregularities and bumps may be qualified (or disqualified) or compensated for in various ways. Some embodiments may utilize acceleration or braking during the course of wheel base 118 passing over irregularities 120. Some embodiments may identify irregularities or bumps identified on one or more wheels (e.g., front wheel 112) that have a signed change in pitch (e.g., based on longitudinal accelerometer readings), which may preclude the possibility of slippage at low friction transitions. Some embodiments may utilize the assumed angle of the jog relative to the vehicle by evaluating a time offset between a left side impact and a right side impact, a yaw rate signal, a lateral acceleration signal, or a steering angle.

As disclosed herein, the vehicle 110 may learn one or more correction factors that may be used to correct future conventionally acquired speed measurements. The detected irregularities and bumps as disclosed herein may then be advantageously used to adaptively correct conventionally acquired vehicle speed (e.g., from sensors conventionally used to acquire vehicle speed), and/or assumptions about the underlying operating parameters of vehicle 110.

Thus, in various embodiments, the vehicle speed recalibration system may have a mechanism for detecting impacts to one or more front wheels and impacts to one or more rear wheels (such as a vertical accelerometer or other mechanism for determining vertical acceleration). The timer mechanism may then determine the duration of time that has elapsed between the time of the first impact and the time of the second impact. The one or more processors may then execute instructions stored in the non-transitory memory that cause the one or more processors to perform operations including calculations and updates. In the calculation, the instantaneous vehicle speed may be calculated from the wheel base of the vehicle and the elapsed duration. In the update, subsequent vehicle speed measurements may be updated based on the instantaneous vehicle speed (e.g., based on a correction factor, as discussed herein).

For some embodiments, the detection criterion of the first impact and/or the second impact may be that the vertical acceleration exceeds a predetermined threshold. The threshold may be set high enough to allow both the front and rear wheels to detect the same impact on a smooth surface. In some embodiments, the operation may include an update in which the value of the operating parameter (e.g., wheel size or final drive ratio) is updated and subsequent vehicle speed measurements are a function of the additional operating parameter. For some embodiments, the operation may include a suspension, wherein the operation is suspended in response to detecting various conditions between the time of the first impact and the time of the second impact, such as a change in the direction of travel of the vehicle exceeding a predetermined threshold, an acceleration of the vehicle exceeding a predetermined threshold, or a braking of the vehicle exceeding a predetermined threshold. In various embodiments, these thresholds may be predetermined non-zero values.

Fig. 2 illustrates an example vehicle 200, which may be substantially similar to vehicle 100. The mechanical connections between the various components are shown as solid lines, while the electrical connections between the various components are shown as dashed lines. The vehicle 200 has a front axle 246 and front wheels located near the front 201 of the vehicle 200. The front wheels include left and right front wheels 241a and 241b, respectively, connected to a front axle 246. The vehicle 200 also has a rear axle 248 and rear wheels located near the rear 203 of the vehicle 200. The rear wheels include left and right rear wheels 243a, 243b that are respectively connected to the rear axle 248. The vehicle 200 has a wheel base 290 that is the distance between the centers of the front wheels 241a and 241b and the centers of the rear wheels 243a and 243b (as discussed herein).

Vehicle 200 includes a suspension system having a front suspension and a rear suspension. The front suspension includes left and right front portions 256a and 256b, and the rear suspension includes left and right rear portions 258a and 258 b. The suspension portions 256a, 256b, 258a, and 258b may include various hydraulic, electrical, and/or mechanical devices (such as coil springs, shock absorbers, etc.). The suspension system may also include one or more active suspension elements that can control vehicle height on an individual corner basis (e.g., a four-corner independently controlled vehicle height), can control vehicle height on an axle-by-axle basis (e.g., front and rear axle vehicle heights), or control vehicle height for a single vehicle height for the entire vehicle.

The vehicle 200 also includes one or more power sources, such as an internal combustion engine and/or one or more electric machines (e.g., motors). The electric machine of the vehicle 200 may be configured to utilize or consume a different energy source than the engine of the vehicle 200. For example, an engine may consume a liquid fuel (e.g., gasoline) to produce an engine output, while an electric machine may consume electrical energy to produce an electric machine output. In various propulsion modes, the front wheels 241a and 241b and/or the rear wheels 243a and 243b may be driven by an engine of the vehicle 200 (e.g., in an engine-only propulsion mode) (e.g., via a driveline, transmission, drive shafts, etc.), by one or more electric machines of the vehicle 200 (e.g., in an electric-only propulsion mode), or both (e.g., in a hybrid manner). In some embodiments where the vehicle 200 has both an internal combustion engine and an electric motor, the vehicle 200 may be referred to as a Hybrid Electric Vehicle (HEV).

The vehicle 200 also has a braking system with front and rear brakes. The front brakes include a left front brake 251a and a right front brake 251b, and the rear brakes include a left rear brake 253a and a right rear brake 253 b. Brakes 251a, 251b, 253a, and 253b may include friction brakes and/or service brakes. When the left front brake 251a, the right front brake 251b, the left rear brake 253a, and the right rear brake 253b are applied, the left front wheel 241a, the right front wheel 241b, the left rear wheel 243a, and the right rear wheel 243b may be slowed down, respectively. The brake system also includes a brake controller 250.

Vehicle 200 includes an onboard electrical energy storage device 212, which may include one or more batteries, one or more capacitors, one or more inductors, and/or one or more other electrical energy storage elements. In some examples, electrical energy storage device 212 may be configured to store electrical energy that may be provided to various electrical loads resident on the vehicle. The electrical energy storage device 212 includes an electrical energy storage device controller 213 and a power distribution module 214. The electrical energy storage device controller 213 may provide charge balancing between various energy storage elements (e.g., battery cells) and communication with other vehicle controllers (e.g., vehicle system controllers, as discussed herein). The power distribution module 214 may control the flow of power into and out of the electrical energy storage device 212.

The vehicle 200 may include a Power Distribution Box (PDB)215 that may be used to route electrical power throughout various circuits and accessories in the vehicle electrical system. The vehicle 200 may also include a High Current Fuse Box (HCFB)245 and may include various fuses (not shown) for protecting the wiring and electrical components of the vehicle 200.

The vehicle control system 260 may communicate with and/or control various portions of the vehicle 200, such as its suspension system, brakes, engine, motors, transmission, electrical energy storage device, etc. The control system 260 may include a vehicle system controller 262, which may in turn include a microcontroller 263 (including, for example, one or more processors), non-transitory memory 264 (e.g., read-only memory), random access memory 265, and analog/digital input/output 266. In some examples, controller 262 may be a single controller of the vehicle. Controller 262 may be programmed with computer-readable data representing instructions executable to perform the methods described below as well as other variations that are contemplated but not specifically listed.

The control system 260 may receive signals and/or information (e.g., sensory feedback) from various sensors 261 coupled to various portions of the vehicle 200. The various sensors may include, for example, temperature sensors, pressure sensors, and air-fuel ratio sensors, as well as other sensors described herein. In response to these signals and/or information, the control system 260 may send control signals to various actuators 267 coupled to various portions of the vehicle 200. The various actuators may include, for example, various valves, throttles, and fuel injectors. The control system 260 may receive information and/or send control signals via one or more vehicle buses, which may extend between various portions of the vehicle 200 in various configurations.

The control system 260 may also receive indications of various operator requested functions of the vehicle 200 (e.g., from the vehicle's human operator 209 or autonomous controller). As an example, the control system 260 may receive sensory feedback from a pedal position sensor 276 in communication with an accelerator pedal 271 depressed by the operator 209. As another example, the control system 260 may receive sensory feedback from a pedal position sensor 277 in communication with a brake pedal 272 depressed by the operator 209. In some embodiments, the brake controller 250 may be responsive to the position of the brake pedal 272 and commands from the controller 262.

The vehicle 200 may also include one or more inertial sensors 285, which may include various longitudinal sensors, lateral sensors, vertical sensors, yaw sensors, roll sensors, and/or pitch sensors (e.g., accelerometers). (the directions of yaw, pitch, and roll are indicated, as well as the directions of lateral and longitudinal acceleration). The vehicle 200 may also include an accelerometer 283 and/or an inclinometer 284.

Data from inertial sensors 285 (as well as data from accelerometer 283 and/or inclinometer 284) may be communicated to controller 262 in various ways in some embodiments, inertial sensors 285 may be electrically coupled to controller 262. control system 260 may adjust engine output, one or more motor outputs, and/or wheel brakes in response to such sensors to improve vehicle stability.

One or more Wheel Speed Sensors (WSS)281 may be respectively coupled to one or more wheels of the vehicle 200. The wheel speed sensor may detect the rotational speed of each wheel. In some embodiments, WSS 281 may include permanent magnet type sensors. One or more Tire Pressure Monitoring Sensors (TPMS) may also be respectively coupled to one or more tires of a wheel in the vehicle. For example, fig. 2 shows a tire pressure sensor 282 coupled to the left rear wheel 243a, which may be configured to monitor the pressure in the tires of the left rear wheel 243 a. (although not explicitly shown, it is understood that each of the four tires indicated in fig. 2 may include at least one WWS 281 and/or at least one tire pressure sensor 282). Wheel speed sensors 281 and tire pressure monitoring sensors 282 may also provide information to control system 260.

The sensors 261 may also include one or more vertical acceleration sensors 291, which may be respectively coupled to one or more wheels of the vehicle 200. In some embodiments, the vertical acceleration sensor 291 may be an accelerometer and may be operable to directly measure vertical acceleration. In some embodiments, the vertical sensors 291 may include other sensors (such as a longitudinal accelerometer, a lateral accelerometer, an inclinometer, a yaw sensor, a roll sensor, and/or a pitch sensor), whose outputs may be used (either locally at the sensors, or by the control system 260) to determine vertical acceleration, such as discussed herein.

The control system 260 (or another portion of the vehicle 200) may receive an output from the vertical acceleration sensor 291 and may use the output to detect impacts on various suspensions and/or wheels of the vehicle 200. Control system 260 may then correct the vehicle speed measurements obtained by, for example, WSS 281. The corrected vehicle speed measurement may then be communicated to the operator 209, for example, and/or may be used by a cruise control system, such as a cruise control system managed by the control system 260.

The vehicle 200 may also include a dashboard 205 and an operator interface 206 by which an operator 209 may adjust the operating state of the vehicle. For example, the operator interface 206 may be configured to initiate and/or terminate operation of the drive train of the vehicle 200 (e.g., by turning the engine and/or one or more electric machines on and off) based on operator input.

Various examples of operator interface 206 may include an interface that requires a physical device, such as an active key, that may be inserted into operator interface 206 to turn on the vehicle, or may be removed to turn off the vehicle. Other examples may include a passive key communicatively coupled to the operator interface 206. The passive key may be configured as an electronic key fob or smart key that does not have to be inserted into or removed from the operator interface 206. Conversely, a passive key may need to be located inside or near (e.g., within a threshold distance) the vehicle 200 and/or the operator interface 206 to enable operation. Other examples may additionally or optionally use a start/stop button that is manually pressed by the operator 209 to turn the vehicle 200 on or off. In other examples, the engine or motor may be turned on or off by a remote computing device (not shown), such as a cellular telephone, which transmits data to a server and the server communicates with the controller 212 to turn on the vehicle, or by a smartphone-based system.

The dashboard 205 may also include a display system 207 configured to display information to an operator 209. By way of non-limiting example, the display system 207 may include a touch screen or Human Machine Interface (HMI) display that enables the operator 209 to view graphical information and enter commands. In some examples, display system 207 may be wirelessly connected to the internet (not shown) via a controller (e.g., controller 262). Thus, in some examples, the operator 209 may communicate with an internet website or software application (app) via the display system 207.

The dashboard 205 may also include an in-vehicle navigation system 208 (e.g., a Global Positioning System (GPS) based navigation system) with which an operator 209 of the vehicle may interact. Navigation system 208 may include one or more location sensors to assist in estimating the location (e.g., geographic coordinates) of the vehicle. For example, the navigation system 208 may receive signals from GPS satellites (not shown) and may identify the geographic location of the vehicle based on the signals. In some examples, the geographic location coordinates may be communicated to the controller 262.

In some examples, navigation system 208 may be integrated with display system 207. In various embodiments, the operator interface 206, the display system 207, and/or the navigation system 208 may interact with the control system 260 and/or the controller 262 in various ways.

FIG. 3 illustrates an exemplary method 300 of identifying road irregularities and correcting operating parameters of a vehicle propulsion system. The method 300 may include detecting 310, identifying 320, deriving 330, and calculating 340. In various embodiments, the method 300 may also include a correction 350.

In detection 310, a first impact to the front suspension and a second impact to the rear suspension (e.g., portions of the front and rear suspensions of vehicle 110 and/or the front and rear suspensions of vehicle 200) may be detected for a vehicle in motion. In identifying 320, detection of the first impact and the second impact may identify irregularities or asperities (such as irregularities 330). In derivation 330, when irregularities or bumps are identified, an instantaneous vehicle speed may be derived based on a first operating parameter of the vehicle (e.g., wheel base 118 of vehicle 110 and/or wheel base 290 of vehicle 200). In calculation 340, a correction factor for a second operating parameter of the vehicle (e.g., wheel size, final drive ratio, or tire air pressure) may be calculated based on the instantaneous vehicle speed, as disclosed herein.

In some embodiments, in correcting 350, subsequent vehicle speed measurements (as disclosed herein) may be corrected according to a formula based on the second operating parameter and the correction factor. For some embodiments, the criterion for detecting the first impact and/or the second impact may be that a vertical acceleration associated with the impact (e.g., a vertical acceleration associated with the front or rear suspension or with one or more wheels) exceeds a predetermined threshold (which may be a predetermined non-zero value).

For some embodiments, the criteria 312 for identifying irregularities or bumps may be that the time duration elapsed between the first impact and the second impact falls within a predetermined range, which in turn may be a function of a vehicle speed measurement and/or a function of a vehicle wheel base. In some embodiments, the criterion 314 for identifying irregularities or bumps may be that the direction of travel of the vehicle remains within a predetermined range between the first impact and the second impact. In some embodiments, the criteria 316 for identifying irregularities or bumps may be that the longitudinal acceleration of the vehicle does not exceed a predetermined threshold between the first impact and the second impact. In some embodiments, the criteria 318 for identifying irregularities or bumps may be that the braking of the vehicle does not exceed a predetermined threshold between the first impact and the second impact. In various embodiments, the acceleration threshold and the braking threshold may be predetermined non-zero values.

FIG. 4 illustrates an exemplary method 400 of calculating an instantaneous vehicle speed and correcting measurements of a vehicle propulsion system based on traversed road irregularities. Method 400 may include detecting 410, starting 420, detecting 430, stopping 440, calculating 450, and correcting 460. In some embodiments, the method 400 may include aborting 470 and/or correcting 480.

In the detection 410, one or more front wheels of the vehicle (e.g., the front wheels 112 of the vehicle 100 and/or the front wheels 241a and 241b of the vehicle 200) may be detected as having passed over bumps. In start 420, a timer may be started in response to detecting that the front wheel has passed over the irregularity. In some embodiments, the timer may be a dedicated device, and in some embodiments, the timer may be implemented at least in part by the vehicle control system and/or a controller thereof (such as vehicle control system 262 and/or controller 260 thereof). In detection 430, one or more rear wheels of the vehicle may be detected as having passed over the irregularity. In stop 440, the timer may be stopped in response to detecting that the rear wheel has passed over the jog. In calculation 450, the instantaneous vehicle speed may be calculated based on an operating parameter of the vehicle (e.g., wheel base 118) and an elapsed duration recorded by the timer (e.g., between the start of the timer and the stop of the timer). In correction 460, subsequent vehicle speed measurements (e.g., conventionally acquired vehicle speed measurements, which may be based on output from a dedicated sensor) may be corrected based on the instantaneous vehicle speed.

In some embodiments, in aborting 470, the method 400 may be aborted in response to any criteria disclosed herein for identifying irregularities or bumps. For example, method 400 may be aborted in response to detecting that one of the front wheels has not crossed a bump, or that one of the rear wheels has not crossed a bump. For some embodiments, in correcting 480, the value of the additional operating parameter (e.g., wheel size or final drive ratio) may be corrected, and the subsequent vehicle speed measurement may be a function of the additional operating parameter.

At least a portion of the methods 300 and/or 400 may be performed by the vehicle 100 and/or the vehicle 200 as shown in fig. 1A and 2. In some embodiments, methods 300 and/or 400 may be performed in real time in a vehicle traveling on a road.

In some embodiments, at least some portions of methods 300 and/or 400 may be incorporated into a controller of a vehicle control system (such as controller 260 of vehicle control system 262 of fig. 2) as executable instructions stored in a non-transitory memory. For some embodiments, at least some portions of methods 300 and/or 400 may be performed via a controller that transforms the operating state of actuators and/or other devices in the physical world (such as actuator 267 of fig. 2). The instructions for performing the methods 300 and/or 400 may be performed by the controller based on instructions stored in a memory of the controller in conjunction with signals received from sensors and/or other devices in the physical world, such as the sensor 26 in fig. 2. Various instructions may provide a control routine.

Fig. 5 depicts a vehicle 500 (which may be substantially similar to vehicle 100 and/or vehicle 200) having a vehicle propulsion system with an internal combustion engine 501. FIG. 5 shows one cylinder of engine 501, as described herein. However, the engine 501 may have a plurality of cylinders similar to the illustrated cylinders, and a corresponding plurality of pistons, intake valves, exhaust valves, fuel injectors, spark plugs, and the like.

The engine 501 may be controlled at least partially by a control system including a controller 512 and by input from a vehicle operator 582 via various input devices. In this example, the input device 580 includes an accelerator pedal and a pedal position sensor 584 for sensing a force applied (e.g., by a foot of the operator 582) and generating a pedal position signal (e.g., proportional to the sensed force). The controller 512 may be substantially similar to the controller 262 of the control system 260.

The engine 501 includes a combustion chamber 530 and a cylinder formed by cylinder walls 532. Piston 536, located therein, may be coupled to crankshaft 540 such that reciprocating motion of the piston is translated into rotational motion of the crankshaft. Crankshaft 540 may be coupled to at least one drive wheel of vehicle 500 via an intermediate transmission system. Further, a starter motor may be coupled to crankshaft 540 via a flywheel to enable a starting operation of engine 501.

Combustion chamber 530 can receive intake air from intake manifold 544 via intake passage 542 and can exhaust combustion gases via exhaust manifold 548. Intake manifold 544 and exhaust manifold 548 can selectively communicate with combustion chamber 530 via an intake valve 552 and an exhaust valve 554, respectively. In some examples, combustion chamber 530 may include two or more intake valves and/or two or more exhaust valves.

Fuel injector 566 is directly coupled to combustion chamber 530 for injecting fuel directly therein (e.g., via direct injection). Fuel may be injected in proportion to the pulse width of the signal received from the controller 512. For example, the fuel injector may be mounted in the side of the combustion chamber or in the top of the combustion chamber. Fuel may be delivered to fuel injector 566 via a fuel system, which may include a fuel tank, fuel pump, and/or fuel rail. In some examples, a high pressure dual stage fuel system may be used to generate the higher fuel pressure. For some examples, combustion chamber 530 may alternatively or additionally include fuel injectors arranged in intake manifold 544 in a configuration such as: this configuration provides what is referred to as port injection of fuel into the intake port upstream of combustion chamber 530.

Distributorless ignition system 588 (e.g., in response to controller 512) provides ignition spark to combustion chamber 530 via spark plug 592. The ignition system may also include an ignition coil (not shown) for increasing the voltage supplied to spark plug 592. In other examples (such as diesel fuel based examples), spark plug 592 may be omitted.

During operation, each cylinder within the engine 501 typically undergoes a four-stroke cycle, including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke. During the intake stroke, generally, the exhaust valve 554 is closed and the intake valve 552 is opened. Air is introduced into combustion chamber 530 via intake manifold 544 and piston 536 moves to the bottom of the cylinder to increase the volume within combustion chamber 530. The position at which piston 536 is near the bottom of the cylinder and at the end of its stroke (e.g., when combustion chamber 530 is at its largest volume) is typically referred to by those skilled in the art as Bottom Dead Center (BDC).

During the compression stroke, intake valve 552 and exhaust valve 554 are closed. Piston 536 moves toward the cylinder head to compress air within combustion chamber 530. The point at which piston 536 is at the end of its stroke and closest to the cylinder head (e.g., when combustion chamber 530 is at its smallest volume) is commonly referred to by those skilled in the art as Top Dead Center (TDC). Fuel is introduced into the combustion chamber in a process known as injection. In a process known as ignition, the injected fuel is ignited by a known ignition device, such as spark plug 592, resulting in combustion.

During the expansion stroke, the expanding gases push piston 536 back to BDC, and crankshaft 540 converts the piston movement into rotational torque of the rotating shaft. Finally, during the exhaust stroke, the exhaust valve 554 opens to release the combusted air-fuel mixture to exhaust manifold 548 and the piston returns to TDC.

It should be noted that the above is shown merely as an example, and that intake and exhaust valve opening and/or closing timings may vary (such as to provide positive or negative valve overlap, late intake valve closing, or various other examples).

Exhaust gas sensor 526 is shown coupled to exhaust manifold 548 upstream of catalytic converter 570 in the direction of exhaust gas flow. Sensor 526 may be any suitable sensor for providing an indication of exhaust gas air/fuel ratio such as a linear oxygen sensor or UEGO (universal or wide-range exhaust gas oxygen), a two-state exhaust gas oxygen sensor or EGO, a HEGO (heated EGO), a NO sensor_xA sensor, an HC sensor, or a CO sensor. In one example, upstream exhaust gas sensor 526 is a UEGO configured to provide an output, such as a voltage signal, that is proportional to the amount of oxygen present in the exhaust gas. Controller 512 may convert the oxygen sensor output to an exhaust air-fuel ratio via an oxygen sensor transfer function.

In one example, converter 570 may include a plurality of catalyst bricks. In another example, multiple emission control devices may be used, each having multiple bricks. In one example, converter 570 may be a three-way catalyst.

The controller 512 is illustrated in fig. 3 as a microcomputer that includes a microprocessor unit 502, input/output ports 504, an electronic storage medium for storing executable programs and calibration values, which in this particular example is illustrated as a read-only memory chip 506 (e.g., non-transitory memory), a random access memory 508, and/or a keep-alive memory 510, which may be interconnected by various control and/or data buses. Other controllers mentioned herein may have similar designs and configurations. The storage medium read-only memory 506 may be programmed with computer readable data representing non-transitory instructions executable by the microprocessor unit 502 for performing at least part of the methods described herein as well as other variations of the methods described herein that are anticipated but not specifically listed.

The controller 512 may receive signals from various sensors coupled to the engine 501. The controller 512 may also receive input from an operator/machine interface (e.g., buttons or a touch screen display). In addition to receiving signals from the sensors previously discussed, the controller 512 may also receive signals including: engine Coolant Temperature (ECT) from temperature sensor 523 coupled to cooling sleeve 514; a measurement of engine manifold pressure (MAP) from pressure sensor 522 coupled to intake manifold 544; an engine position signal from a crankshaft position sensor 518 (e.g., a hall effect sensor or another type of sensor) that senses a position of the crankshaft 540; measurements of air mass entering the engine from sensor 520; and/or a manifold pressure signal (which may provide an indication of vacuum or pressure in intake manifold 544). Atmospheric pressure may also be sensed (sensor not shown) for processing by the controller 512.

In one example, the crankshaft position sensor 518 may generate a predetermined number of equally spaced pulses per rotation of the crankshaft from which engine speed (RPM) may be generated or determined (e.g., via the controller 512). Thus, the crankshaft position sensor 518 may also function as an engine speed sensor. During engine operation, engine torque may be inferred from the output of the MAP sensor 522 and engine speed. Further, the sensor, together with the detected engine speed, may be the basis for estimating the charge (including air) drawn into the cylinder.

The vehicle 500 is depicted as having a spark ignition engine. However, in various examples, the vehicle propulsion system of the vehicle 500 may include a diesel engine, a turbine, or an electric machine. In some examples, the vehicle 500 may be a hybrid vehicle (e.g., a hybrid electric vehicle) having multiple torque sources available to one or more wheels 575. In other examples, the vehicle 500 is a conventional vehicle having only an engine or an electric vehicle having only an electric machine.

In the example shown, the vehicle 500 includes an engine 501 and a motor 572. The electric machine 572 may be a motor or a motor/generator. When the one or more clutches 576 are engaged, the crankshaft 540 of the engine 501 and the motor 572 are connected to wheels 575 via a transmission 574. In the depicted example, the first clutch 576 is disposed between the crankshaft 540 and the motor 572, and the second clutch 576 is disposed between the motor 572 and the transmission 574. The controller 512 can signal an actuator of each clutch 576 to engage or disengage the clutch to connect or disconnect the crankshaft 540 from the motor 572 and components connected thereto, and/or to connect or disconnect the motor 572 from the transmission 574 and components connected thereto. The transmission 574 may be a gearbox, a planetary gear system, or another type of transmission. The powertrain may be configured in various ways, including being configured as a parallel, series, or series-parallel hybrid vehicle.

The electric machine 572 receives electrical power from the traction battery 578 to provide torque to the vehicle wheels 575. The electric machine 572 may also operate as a generator to provide electrical power to charge the battery 578, for example, during braking operations. Thus, the methods 300 and 400 may be performed by a hybrid vehicle, such as the vehicle 500.

In this manner, by employing the mechanisms and methods disclosed herein, a vehicle may advantageously account for variations in actual values of operating parameters (such as wheel size and final drive ratio) as compared to assumed or expected values for those operating parameters. By making instantaneous vehicle speed measurements based on a relatively more fixed operating parameter of the vehicle, such as the wheelbase of the vehicle, the actual values of the other operating parameters may be properly accounted for. Thus, a technical effect of the disclosed mechanisms and methods may be to adjust or otherwise improve vehicle speed measurements when the operating parameters upon which those vehicle speed measurements are based have changed.

In a first method of the methods and systems discussed herein, a first example of a method comprises: detecting, for a vehicle in motion, a first impact on a front suspension and a second impact on a rear suspension to identify a bump; when the irregularity is identified, deriving an instantaneous vehicle speed based on a first operating parameter of the vehicle; and calculating a correction factor for a second operating parameter of the vehicle based on the instantaneous vehicle speed. In a second example of the method, based on the first example, the first operating parameter of the vehicle is a wheel base of the vehicle. In a third example of the method, based on the first or second example, the second operating parameter of the vehicle is one of: wheel size, final drive ratio, and tire pressure. On the basis of any of the first to third examples, a fourth example of the method further includes: subsequent vehicle speed measurements are corrected according to a formula based on the second operating parameter and the correction factor. In a fifth example of the method, based on any of the first to fourth examples, the criterion for detecting at least one of the first impact and the second impact is that a vertical acceleration exceeds a predetermined threshold. On the basis of any one of the first to fifth examples, in a sixth example of the method, the criterion for identifying the asperity is that a duration of time elapsed between the first impact and the second impact falls within a predetermined range. In a seventh example of the method, the predetermined range is a function of a vehicle speed measurement, based on the sixth example. In an eighth example of the method, based on the sixth or seventh example, the predetermined range is a function of a vehicle wheel base. On the basis of any one of the first to eighth examples, in a ninth example of the method, the criterion for identifying the concavo-convex portion is that a traveling direction of the vehicle is kept within a predetermined range between a time of the first impact and a time of the second impact. On the basis of any one of the first to ninth examples, in a tenth example of the method, the criterion for identifying the asperity is that a longitudinal acceleration of the vehicle does not exceed a predetermined threshold between a time of the first impact and a time of the second impact. On the basis of any one of the first to tenth examples, in an eleventh example of the method, the criterion for identifying the asperity is that braking of the vehicle does not exceed a predetermined threshold between a time of the first impact and a time of the second impact.

In a second method of the methods and systems discussed herein, a first example of a method of correcting a vehicle speed measurement includes: detecting that one or more front wheels of the vehicle have passed over the irregularity; starting a timer in response to detecting that one or more front wheels have passed over the jog; detecting that one or more rear wheels of the vehicle have passed over the reliefs; stopping the timer in response to detecting that one or more rear wheels have passed over the jog; calculating an instantaneous vehicle speed based on operating parameters of the vehicle and an elapsed duration recorded by a timer; and correcting subsequent vehicle speed measurements based on the instantaneous vehicle speed. In a second example of the method, on the basis of the first example, the operating parameter of the vehicle is a wheelbase of the vehicle. On the basis of the first example or the second example, a third example of the method further includes: the method is aborted in response to detecting that one of the front wheels has not crossed the relief, or one of the rear wheels has not crossed the relief. In a fourth example of the method, based on any of the first to third examples, the subsequent vehicle speed measurement is based on an output from a dedicated sensor. On the basis of any of the first to fourth examples, a fifth example of the method further includes: the value of an additional operating parameter selected from wheel size or final reduction ratio is corrected and the subsequent vehicle speed measurement is a function of the additional operating parameter.

In a third method of the methods and systems discussed herein, a first example of a vehicle speed recalibration system for a vehicle having a set of front wheels and a set of rear wheels comprises: a mechanism for detecting a first impact in which at least one of the front wheels has passed over the asperity; a mechanism for detecting a second impact in which at least one of the rear wheels has passed over the asperity; a timer mechanism for determining a duration of time elapsed between a first time at which a first impact is detected and a second time at which a second impact is detected; and one or more processors to execute instructions stored in the non-transitory memory, the instructions to cause the one or more processors to perform operations comprising: calculating an instantaneous vehicle speed from the wheelbase of the vehicle and the elapsed duration; and updating subsequent vehicle speed measurements based on the instantaneous vehicle speed. In a second example of the vehicle speed recalibration system, based on the first example, the criterion for detecting at least one of the first impact and the second impact is that the vertical acceleration exceeds a predetermined threshold. In a third example of the vehicle speed recalibration system based on the first example or the second example, the operations further comprise: the value of an operating parameter selected from wheel size or final reduction ratio is updated, and subsequent vehicle speed measurements are a function of the additional operating parameter. In a fourth example of the vehicle speed recalibration system based on any of the first to third examples, the operations further comprise: suspending operation in response to detecting any of the following between the first time and the second time: the change in the direction of travel of the vehicle exceeds a predetermined threshold; the longitudinal acceleration of the vehicle exceeds a predetermined threshold; or the braking of the vehicle exceeds a predetermined threshold.

It should be noted that the example control and estimation routines included herein may be used with various engine and/or vehicle system configurations. The control methods and routines disclosed herein may be stored as executable instructions in a non-transitory memory and may be executed by a control system, including a controller, in conjunction with various sensors, actuators, and other engine hardware. The specific routines described herein may represent one or more of any number of processing strategies such as event-driven, interrupt-driven, multi-tasking, multi-threading, and the like. As such, various acts, operations, and/or functions illustrated may be performed in the sequence illustrated, in parallel, or in some cases omitted. Likewise, the order of processing is not necessarily required to achieve the features and advantages of the example embodiments described herein, but is provided for ease of illustration and description. One or more of the illustrated acts, operations, and/or functions may be repeatedly performed depending on the particular strategy being used. Additionally, the described acts, operations, and/or functions may graphically represent code to be programmed into the non-transitory memory of the computer readable storage medium in the engine control system, with the described acts being implemented by execution of instructions in combination with the electronic controller in the system including the various engine hardware components.

It will be appreciated that the configurations and routines disclosed herein are exemplary in nature, and that these specific embodiments are not to be considered in a limiting sense, because numerous variations are possible. For example, the above techniques may be applied to V-6, I-4, I-6, V-12, opposed 4, and other engine types. Furthermore, unless explicitly stated to the contrary, the terms "first," "second," "third," and the like do not denote any order, position, quantity, or importance, but rather are used merely as labels to distinguish one element from another. The subject matter of the present disclosure includes all novel and non-obvious combinations and subcombinations of the various systems and configurations, and other features, functions, and/or properties disclosed herein.

As used herein, the term "about" is to be construed as meaning ± 5% of the range, unless otherwise specified.

The following claims particularly point out certain combinations and subcombinations regarded as novel and nonobvious. These claims may refer to "an" element or "a first" element or the equivalent thereof. Such claims should be understood to include incorporation of one or more such elements, neither requiring nor excluding two or more such elements. Other combinations and subcombinations of the disclosed features, functions, elements, and/or properties may be claimed through amendment of the present claims or through presentation of new claims in this or a related application. Such claims, whether broader, narrower, equal, or different in scope to the original claims, also are regarded as included within the subject matter of the present disclosure.