Device and method for detecting driving conditions from rotating wheels

Abstract

The sensor assembly may include one or more sensors mountable on a wheel of the vehicle and one or more processors electrically coupled to the one or more sensors for determining a vehicle driving condition based on the first sensor signal and the second sensor signal. A method for determining a vehicle driving condition based on the sensor signals, as well as a wheel assembly including the wheel and the sensor assembly, are also disclosed.

Description

[Technical field]

[0001] This application relates generally to vehicle sensors, and more particularly to vehicle sensors that can be mounted on tires, rims, and wheels of a vehicle. [Background technology]

[0002] Advances in automotive sensing technology are improving the safety and performance of automotive vehicles, which is creating a greater demand for advanced sensing applications to complement existing electronic safety systems. Summary of the Invention

[0003] Such demands call for the measurement of temperature, pressure, acceleration, and forces (static and dynamic) exerted on tires, wheels, and automotive vehicles. However, many of these sensors require power for operation and data transmission. In addition, frequent measurement (and transmission) of data increases the amount of power required for such sensors. Energy storage devices (e.g., lithium-ion batteries) have limited capacity and often suffer from low durability, difficulty in replacement, and poor sustainability. Such energy storage devices are typically subject to accelerated discharge cycles, resulting in frequent or premature replacement of the entire sensor module, thereby increasing the overall cost of ownership and maintenance of the automotive vehicle.

[0004] The devices and methods described herein address the challenges associated with conventional devices and methods for providing power to a sensor module. Utilizing an energy harvesting device (e.g., a generator that converts kinetic, thermal, light, and mechanical energy available from an automotive vehicle, such as wheel rotation, acceleration, deceleration, and / or vibration, into electrical energy) can replace conventional energy storage devices or, when used in conjunction with them, can extend the life expectancy of such energy storage devices. Such energy harvesting devices are typically mounted in locations where an energy source (e.g., kinetic, thermal, light, or mechanical energy) is readily available (e.g., adjacent to the bead area of ​​a tire mounted on a wheel). Additionally, the energy harvesting device can be used as a sensor in its own right, since the electrical signal from the energy harvesting device contains information about the operation of the energy harvesting device and the portion of the tire and / or wheel to which the energy harvesting device is mounted. In particular, if the energy harvesting device is mounted in a location where source energy is readily available, the energy harvesting device can have high sensitivity in detecting changes in source energy (e.g., motion, heat, light, or mechanical energy such as vibration).

[0005] According to some embodiments, a method includes receiving a first sensor signal and a second sensor signal from one or more sensors mounted adjacent wheels of a vehicle, and determining a driving condition of the vehicle based on the first sensor signal and the second sensor signal.

[0006] According to some embodiments, the sensor assembly includes one or more sensors mountable on wheels of a vehicle and one or more processors electrically coupled to the one or more sensors for determining a driving condition of the vehicle based on a first sensor signal and a second sensor signal.

[0007] According to some embodiments, a wheel assembly includes a wheel and any of the sensor assemblies described herein, the sensor assembly being mounted adjacent to the wheel. [Brief description of the drawings]

[0008] The disclosed devices and methods enable electrical connection between an energy harvesting device and other electrical components located inside the tire and / or wheel.

[0009] For a better understanding of the various embodiments described, please refer to the following detailed description taken in conjunction with the following drawings, in which reference numerals refer to corresponding parts throughout the drawings, in which: [Figure 1A] FIG. 1 is a schematic diagram illustrating a component of an automobile, according to some embodiments. [Figure 1B] FIG. 1 is a schematic diagram illustrating an energy harvesting device mounted on a wheel according to some embodiments. [Figure 1C] FIG. 1 is a schematic diagram illustrating a vehicle having energy harvesting devices mounted on its wheels, according to some embodiments. [Figure 1D] 1 illustrates a tire, according to some embodiments. [Figure 1E] FIG. 1E is a cross-sectional view of the tire shown in FIG. 1D according to some embodiments. [Figure 1F] FIG. 1 is a schematic diagram illustrating an energy harvester according to some embodiments. [Figure 2A] 1 illustrates an example signal from an energy harvester according to some embodiments. [Figure 2B] 1 illustrates example electrical components used to process signals from an energy harvester in accordance with some embodiments. [Figure 3A] FIG. 1 is a schematic diagram illustrating an energy harvesting device mounted on a wheel according to some embodiments. [Figure 3B]1 illustrates example electrical components that may be used to process signals from an energy harvester in accordance with some embodiments. [Figure 3C] FIG. 1 is a schematic diagram illustrating an energy harvesting device mounted on a wheel according to some embodiments. [Figure 4A] 1 shows example signals from two energy harvesters along with outputs from an accelerometer indicating acceleration and deceleration of the vehicle in its direction of travel, according to some embodiments. [Figure 4B] 4B illustrates the difference between signals from the two energy harvesters shown in FIG. 4A according to some embodiments. [Figure 4C] FIG. 4C is an expanded view of the difference signal shown in FIG. 4B according to some embodiments. [Figure 4D] 13 illustrates a reference waveform from a sensor module according to some embodiments. [Figure 4E] 4E shows magnified views of different regions of the reference waveform shown in FIG. 4D, according to some embodiments. [Figure 4F] 4 illustrates an example cross-correlation process according to some embodiments. [Figure 4G] 1 illustrates an example correlation mapping according to some embodiments. [Figure 5A] FIG. 2 is a block diagram illustrating active control of a brake actuator according to some embodiments. [Figure 5B] FIG. 1 is a block diagram illustrating active control of a motor according to some embodiments. [Figure 6] FIG. 2 is a flow diagram illustrating a method for processing signals from one or more sensors mounted adjacent wheels of a vehicle, according to some embodiments. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Reference will now be made by way of these examples to the embodiments illustrated in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the various described embodiments. However, it will be apparent to one of ordinary skill in the art that the various described embodiments may be practiced without these specific details. In other instances, methods, procedures, components, circuits, and networks that are well known to those skilled in the art have not been described in detail so as not to unnecessarily obscure aspects of the embodiments.

[0011] 1A is a schematic diagram illustrating components of a vehicle 100 (e.g., an automobile) according to some embodiments. In some embodiments, the vehicle 100 includes a wheel 104 and a tire 102 mounted on the wheel 104.

[0012] FIG. 1B is a schematic diagram illustrating an energy harvesting device 106 mounted adjacent to (e.g., mounted on) a wheel 104, according to some embodiments. In FIG. 1B, the energy harvesting device 106 is positioned adjacent to the rim of the wheel 104. Positioning the energy harvesting device 106 adjacent to the rim of the wheel 104 is advantageous for energy harvesting devices that utilize centrifugal force, its deformation, and / or associated vibrations for energy harvesting (e.g., converting kinetic or mechanical energy to electrical energy). Although FIG. 1B shows only one energy harvesting device 106 mounted on the wheel 104, in some embodiments, two or more energy harvesting devices are mounted on the wheel 104. In some embodiments, the energy harvesting device 106 is positioned adjacent to the rim on the side of the wheel facing away from the vehicle. In some embodiments, the energy harvesting device 106 is positioned adjacent to the rim on the side of the wheel facing towards the vehicle.

[0013] 1C is a schematic diagram illustrating a vehicle 100 having energy harvesting devices 106 mounted on wheels 104, according to some embodiments. In some embodiments, each wheel 104 includes one or more energy harvesting devices. In some embodiments, the vehicle 100 includes electrical components (e.g., a controller) in communication (e.g., wireless communication) with the energy harvesting devices 106 and configured to aggregate data from the energy harvesting devices 106. In some embodiments, the electrical components are configured to determine driving conditions, braking conditions, and / or load distribution based on the aggregated data from the energy harvesting devices 106.

[0014] Figure ID illustrates a tire 102, according to some embodiments. The tire 102 has a sidewall 112 and a tread region 194, on which electrical connectors may be mounted to electrically connect an energy harvesting device to one or more electrical components disposed within the tire 102. Figure ID also shows the plane ID from which the cross section shown in Figure IE was taken.

[0015] FIG 1E is a cross-sectional view of the tire 102 shown in FIG 1D according to some embodiments. The tire 102 has a tread region 194 extending between two sidewalls 112-1 and 112-2 (one of which may be referred to as an outer sidewall and the other as an inner sidewall, or vice versa, depending on the orientation of the tire on the wheel). The tire 102 has an outer surface 114 and an inner surface 116, the outer surface 114 including a portion 114-1 of the outer surface 114 on the outer sidewall 112-1 and a portion 114-2 of the outer surface 114 on the inner sidewall 112-2, and the inner surface 116 including a portion 116-2 of the inner surface 116 on the inner sidewall 112-2. The tire 102 also has bead regions 118-1 and 118-2 that contact the rim 192 of the wheel 104 when the tire 102 is mounted on the wheel 104. In Figure 1E, the bead regions 118-1 and 118-2 also include bead wires 122-1 and 122-2. In Figure 1E, the tire also includes one or more belts 124 within the tread region 194.

[0016] Although the tire 102 has an open shape (e.g., air can freely enter the space 120 between the sidewalls 112-1 and 112-2 through an opening toward the center of the tire when the tire is not mounted on a wheel), when the tire 102 is mounted on a wheel, the rim 192 of the wheel seals the opening such that the air in the space 120 is maintained within the space 120. This space 120 is referred to herein as the interior space of the tire 102.

[0017] In some configurations, one or more electrical components 140 are located within the volume 120 of the tire 102 (e.g., one or more sensors measuring rotation, acceleration, deceleration, vibration, temperature, pressure, etc.), while one or more energy harvesting devices are located outside the volume 120 (e.g., the region 130 between the rim 192 or its rim lip and the bead region 118-1 or 118-2). In some embodiments, the electrical connector 142 relays power and / or electrical signals from the one or more energy harvesting devices located outside the volume 120 to the one or more electrical components 140 located within the volume 120. In some embodiments, the vehicle includes one or more processors communicatively coupled to respective electrical components at each wheel of the vehicle. For example, each set of electrical components is configured to process / analyze energy harvester signals for a particular wheel, and the processor is configured to process / analyze (e.g., compare) energy harvester signals between the wheels.

[0018] 1F is a schematic diagram illustrating an energy harvester 400 (also referred to as an energy generator, an energy harvesting module, or an energy harvesting sensor) according to some embodiments. In some embodiments, one or more of the energy harvesters described herein (e.g., energy harvester 106 described with respect to FIG. 1B) have a structure that corresponds to or is similar to the structure of energy harvester 400.

[0019] In FIG. 1F, energy harvester 400 includes a cantilever 402. In some embodiments, cantilever 402 is a protruding beam supported by one end. In some embodiments, cantilever 402 has a uniform width and a uniform thickness along its length, as shown in FIG. 1F. In some embodiments, cantilever 402 (1) has a non-uniform width along its length, but its thickness remains uniform along its length, (2) has a non-uniform thickness along its length, but its width remains uniform along its length, or (3) has a non-uniform width and a non-uniform thickness along its length.

[0020] In some embodiments, the cantilever 402 includes a piezoelectric material 404. Examples of piezoelectric materials include gallium nitride, indium nitride, aluminum nitride, zinc oxide, barium titanate, lead zirconate titanate, potassium niobate, sodium tungstate, Ba2NaNb5O5, Pb2KNb5O5, single crystal zinc oxide, langasite, gallium orthophosphate, lithium niobate, lithium tantalate, sodium potassium niobate, bismuth ferrite, sodium niobate, bismuth titanate, sodium bismuth titanate, quartz, berlinite, topaz, lead titanate, and piezoelectric polymers such as polyvinylidene fluoride, polyamide, paralym-C, polyimide, and polyvinylidene chloride. Piezoelectric materials are capable of generating an electric charge in response to an applied mechanical strain. Thus, when the cantilever 402 bends, the piezoelectric material provides an electric charge that indicates an amplitude and rate of strain as a result of how much the cantilever 402 bends (e.g., the displacement of the free end of the cantilever 402). Similarly, when the cantilever 402 vibrates, the piezoelectric material within the cantilever 402 provides an (oscillating) electrical signal that corresponds to the vibration of the cantilever 402.

[0021] The length, width, and thickness of the cantilever 402 are selected to obtain the desired performance of the energy harvester 400. In some embodiments, the length is between 1 cm and 30 cm, 1 cm and 10 cm, 5 cm and 15 cm, 10 cm and 20 cm, 15 cm and 25 cm, 20 cm and 30 cm, 1 cm and 5 cm, 5 cm and 10 cm, 10 cm and 15 cm, 15 cm and 20 cm, 20 cm and 25 cm, 25 cm and 30 cm, 1 cm and 3 cm, 2 cm and 4 cm, 3 cm and 5 cm, 4 cm and 6 cm, 5 cm and 7 cm, 6 cm and 8 cm, 7 cm and 9 cm, or 8 cm and 10 cm. In some embodiments, the length is approximately 1 cm, approximately 2 cm, approximately 3 cm, approximately 4 cm, approximately 5 cm, approximately 6 cm, approximately 7 cm, approximately 8 cm, approximately 9 cm, approximately 10 cm, approximately 15 cm, approximately 20 cm, approximately 25 cm, or approximately 30 cm. In some embodiments, the width is between 1 cm and 10 cm, between 5 cm and 15 cm, between 10 cm and 20 cm, between 1 cm and 5 cm, between 5 cm and 10 cm, between 10 cm and 15 cm, between 15 cm and 20 cm, between 1 cm and 4 cm, between 2 cm and 5 cm, between 3 cm and 6 cm, between 4 cm and 7 cm, between 5 cm and 8 cm, between 6 cm and 9 cm, or between 7 cm and 10 cm. In some embodiments, the width is approximately 1 cm, approximately 2 cm, approximately 3 cm, approximately 4 cm, approximately 5 cm, approximately 6 cm, approximately 7 cm, approximately 8 cm, approximately 9 cm, approximately 10 cm, approximately 15 cm, or approximately 20 cm. In some embodiments, the thickness of the cantilever 402 is between 100 μm and 5 mm, between 100 μm and 3 mm, between 1 mm and 4 mm, between 2 mm and 5 mm, between 100 μm and 1 mm, between 500 μm and 1.5 mm, between 1 mm and 2 mm, between 1.5 mm and 2.5 mm, between 2 mm and 3 mm, between 2.5 mm and 3.5 mm, between 3 mm and 4 mm, between 3.5 mm and 4.5 mm, between 4 mm and 5 mm, between 100 μm and 500 μm, between 500 μm and 1 mm, between 1 mm and 1.5 mm, between 1.5 mm and 2 mm, between 2 mm and 2.5 mm, or between 2.5 mm and 3 mm. In some embodiments, the thickness of the cantilever 402 is approximately 100 μm, approximately 200 μm, approximately 300 μm, approximately 400 μm, approximately 500 μm, approximately 600 μm, approximately 1 mm, approximately 2 mm, approximately 3 mm, approximately 4 mm, or approximately 5 mm.In some embodiments, the thickness of the layer of piezoelectric material in the cantilever 402 is between 10 μm and 1 mm, between 100 μm and 500 μm, between 200 μm and 600 μm, between 300 μm and 700 μm, between 400 μm and 800 μm, between 500 μm and 900 μm, between 600 μm and 1 mm, between 50 μm and 150 μm, between 100 μm and 200 μm, between 150 μm and 250 μm, between 200 μm and 300 μm, between 250 μm and 350 μm, between 300 μm and 400 μm, between 350 μm and 450 μm, between 400 μm and 500 μm, between 500 μm and 600 μm, between 600 μm and 700 μm, between 700 μm and 800 μm, or between 800 μm and 900 μm. In some embodiments, the thickness of the layer of piezoelectric material in the cantilever 402 is approximately 100 μm, approximately 200 μm, approximately 300 μm, approximately 400 μm, approximately 500 μm, approximately 600 μm, approximately 700 μm, approximately 800 μm, approximately 900 μm, approximately 1 mm, approximately 2 mm, approximately 3 mm, approximately 4 mm, or approximately 5 mm.

[0022] In some embodiments, the cantilever 402 includes a single layer of piezoelectric material. In some embodiments, the cantilever 402 includes two or more layers of piezoelectric material. In some embodiments, the two or more layers of piezoelectric material are separated by one or more interleaved layers of insulating or conductive material.

[0023] FIG. 1F also shows a clamp 406 configured to support and secure one end of the cantilever 402. In FIG. 1F, the clamp 406 has a plate shape. However, clamps having any other shape may be used. Although FIG. 1F shows the clamp 406 located at the tip of the cantilever 402, the clamp 406 need not be aligned with the tip of the cantilever 402. For example, the clamp 406 may be positioned offset from the tip of the cantilever 402 (e.g., by 1 mm, 2 mm, 3 mm, 4 mm, 5 mm, 7 mm, 10 mm, 15 mm, 20 mm, 25 mm, etc.) so that there is an overhang when the clamp 406 is positioned on the cantilever 402. In some embodiments, the cantilever 402 extends from the clamp 406 in a single direction. In some embodiments, the cantilever 402 extends from the clamp 406 in multiple directions (e.g., two opposite directions).

[0024] In some embodiments, the clamp 406 and / or the cantilever 402 have one or more through holes for fastening the cantilever 402 and the clamp to a base (e.g., a wheel rim and / or other component). For example, screws may be placed through corresponding through holes to fasten the clamp 406 and the cantilever 402. Alternatively, other mechanisms may be used to fasten the cantilever 402. For example, the clamp 406 and the cantilever 402 may have slits into which clips are inserted to fasten the clamp 406 and the cantilever 402. In another example, the cantilever 402 may be integrated with its base, in which case the clamp 406 is omitted. In some embodiments, the clamp 406 and / or the cantilever 402 include one or more components for attaching the energy harvester 400 to a wheel (e.g., a wheel rim and / or a tire). In some embodiments, the energy harvester 400 is configured to be mounted to the interior space 120 of the tire 102 (e.g., mounted to the rim of the tire such that the cantilever receives strain due to deformation of the inner surface of the tire 102). In some embodiments, the energy harvester 400 is configured to be mounted to the exterior space 130 of the tire 102 (e.g., mounted to the rim of the tire such that the cantilever receives strain due to deformation of the outer surface of the tire 102).

[0025] 2A illustrates an example signal (e.g., an electrical signal) from an energy harvester 106, according to some embodiments. The signal from the energy harvester 106 is generated while the wheel 104 to which the energy harvester 106 is attached is rotating (e.g., while the vehicle having the energy harvester 106 is moving).

[0026] FIG. 2B illustrates exemplary electrical components used to process signals from the energy harvester 106, according to some embodiments. In FIG. 2B, an analog front end (AFE) circuit 202 receives and processes signals generated by the energy harvester 106 at two different times or within two different time windows (t1 and t2 shown in FIG. 2A). In some embodiments, the AFE circuit 202 includes (or is coupled to) a memory for storing signals from the energy harvester 106 such that the signals received from the energy harvester 106 at a first time are compared (or processed) with signals received from the energy harvester 106 at a second time subsequent to the first time. In some embodiments, the AFE circuit 202 includes (or is coupled to) a propagation delay circuit such that the signals received from the energy harvester 106 at a first time are compared (or processed) with signals received from the energy harvester 106 at a second time. In some embodiments, the AFE circuit 202 combines a signal received from the energy harvester 106 at a first time and a signal received from the energy harvester 106 at a second time (e.g., the AFE circuit 202 generates a signal representing a superposition of the signal received from the energy harvester 106 at the first time and the signal received from the energy harvester 106 at the second time, or generates a signal representing the difference between the signal received from the energy harvester 106 at the first time and the signal received from the energy harvester 106 at the second time).

[0027] In FIG. 2B, an analog-to-digital converter (ADC) 204 receives the combined signal from the AFE circuitry 202, and the (digital) output from the ADC 204 is provided to one or more processors 206. In some embodiments, the one or more processors 206 comprise digital logic circuits. In some embodiments, the AFE circuitry 202, the ADC 204, and the one or more processors 206 correspond to or are included in one or more electrical components 140 shown in FIG. 1E. In some embodiments, the AFE circuitry 202, the ADC 204, and the one or more processors 206 are packaged separately. In some embodiments, the AFE circuitry 202, the ADC 204, and the one or more processors 206 are integrated into a single package (e.g., within a single semiconductor package).

[0028] As illustrated in FIG. 2B, the combined signal may be sinusoidal when the vehicle is moving at a steady state (and the wheels are rotating at a steady state). Thus, in some embodiments, the one or more processors 206 determine whether the combined signal is sinusoidal (e.g., by performing a Fourier transform and determining whether the combined signal is sinusoidal based on the number and amplitude of different frequency components). In some embodiments, the vehicle (and / or wheels) are considered to be in a steady state according to the determination that the composite signal is sinusoidal (or substantially sinusoidal). On the other hand, the combined signal may not be sinusoidal while the vehicle is accelerating or decelerating (and / or while other vehicle events such as brake creep, squealing, and jerks are occurring, and / or while road conditions such as bumpy roads, potholes, and slippery roads are experienced by the vehicle and / or wheels, and / or while the vehicle weight distribution on the wheels is uneven). Thus, in some embodiments, the vehicle (and / or wheels) are considered to be not in a steady state according to the determination that the composite signal is not sinusoidal (or substantially not sinusoidal). In some embodiments, a combined signal is received from multiple wheels (e.g., each of the wheels of a vehicle) and differences between the combined signals are used to determine performance differences between the wheels (e.g., due to load distribution, tire inflation, tire wear, etc.).

[0029] FIG. 3A is similar to FIG. 1B, except that in FIG. 3A, according to some embodiments, two energy harvesters 106-1 and 106-2 are positioned adjacent to the wheel 104. In some embodiments, the energy harvester 106-1 and the energy harvester 106-2 are positioned in opposite directions from the center of the wheel 104 (e.g., the angle formed by the direction from the center of the wheel 104 to the energy harvester 106-1 and the direction from the center of the wheel 104 to the energy harvester 106-2 is 180°). In some embodiments, the two energy harvesters are substantially opposite each other (e.g., the angle between them is in the range of 160° to 200°).

[0030] FIG. 3B is similar to FIG. 2B, except that in FIG. 3B, the AFE circuit 202 receives signals from two separate energy harvesters (e.g., energy harvesters 106-1 and 106-2 shown in FIG. 3A) instead of one energy harvester, according to some embodiments. In some embodiments, the AFE circuit 202 combines the signals received from the energy harvester 106-1 and the signals received from the energy harvester 106-2 (e.g., the AFE circuit 202 generates a signal that represents a superposition of the signals received from the energy harvester 106-1 and the signals received from the energy harvester 106-2, or a difference between the signals received from the energy harvester 106-1 and the signals received from the energy harvester 106-2). In some embodiments, the signals from the two energy harvesters are generated in unison (e.g., simultaneously). Thus, electrical components for storing signals from one or both energy harvesters or delaying signals from one or both energy harvesters may not be required in such a configuration.

[0031] Although Figures 2B and 3B depict certain electrical components, in some embodiments, additional components may be used (e.g., to perform additional operations such as inverting a signal or phase matching a signal). In some embodiments, the operations described with respect to Figures 2B and 3B are performed using additional or fewer components (e.g., a particular operation may be performed by two or more components). In some embodiments, two or more components shown in Figures 2B and 3B may be combined or integrated. For the sake of brevity, such details will not be repeated herein.

[0032] 3C is similar to FIG 3A, except that in FIG 3C, according to some embodiments, the two energy harvesters 106-1 and 106-2 are not arranged in opposite directions. For example, the angle formed by the direction from the center of the wheel 104 to the energy harvester 106-1 and the direction from the center of the wheel 104 to the energy harvester 106-2 is not 180° (e.g., 1°, 5°, 10°, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170°, or 179°, or within an interval between any two of the aforementioned values). Placing two energy harvesters adjacent to each other (e.g., at an angle of less than 45°, 30°, 15°, 10°, or 5°) can make it easier to detect irregularities in road conditions (e.g., bumps) in some scenarios.

[0033] 3C, more than two energy harvesters may be mounted adjacent to the wheel 104. For example, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, or more energy harvesters may be mounted adjacent to the wheel 104. In some embodiments, the energy harvesters are radially symmetrically positioned adjacent to the wheel 104.

[0034] 4A illustrates example signals from two energy harvesters (located on opposite sides as shown in FIG. 3A) along with outputs from an accelerometer indicative of acceleration and deceleration of the vehicle in the direction of travel, according to some embodiments. Specifically, FIG. 4A illustrates example signals from a first energy harvester 402 (Ch0), a second energy harvester 404 (Ch1), and a vehicle accelerometer 406.

[0035] 4B shows an example difference between signals from two energy harvesters along with an output from an accelerometer indicative of acceleration and deceleration of the vehicle in the direction of travel, according to some embodiments. Specifically, FIG. 4B shows an example signal difference 408 between a first energy harvester and a second energy harvester. FIG. 4B also shows a signal from a vehicle accelerometer 410.

[0036] Figure 4C is a close-up of the signal difference shown in Figure 4B along with the output from an accelerometer indicating acceleration and deceleration of the vehicle in the direction of travel. Figure 4C shows that, according to some embodiments, the energy harvester detects (in signal 408) vehicle braking shortly after the braking action is applied (e.g., less than 1 second, 0.9 seconds, 0.8 seconds, 0.7 seconds, 0.6 seconds, 0.5 seconds, 0.4 seconds, 0.3 seconds, 0.2 seconds, etc.).

[0037] FIG. 4D illustrates a reference waveform 411 from a sensor module, according to some embodiments. FIG. 4D illustrates separate portions of the waveform 411, indicated by regions 412, 414, 416, 418, and 420. FIG. 4E illustrates a close-up view of different regions of the waveform illustrated in FIG. 4D, according to some embodiments. In some embodiments, region 412 corresponds to an acceleration of the vehicle. In some embodiments, region 414 corresponds to the vehicle transitioning from an accelerating state to a constant speed state. In some embodiments, region 416 corresponds to the vehicle traveling at a constant speed (e.g., transitioning from an accelerating state to a constant speed state). In some embodiments, region 418 corresponds to the vehicle starting to decelerate from a constant speed (e.g., transitioning from a constant speed state to a decelerating state). In some embodiments, region 420 corresponds to deceleration of the vehicle.

[0038] In some embodiments, a cross-correlation metric (e.g., a measure of similarity of two sequences as a function of displacement of one relative to the other) is used to identify state changes in vehicle movement. FIG. 4F illustrates an exemplary cross-correlation process, according to some embodiments. As shown in FIG. 4F, a reference signal 430 is obtained (e.g., corresponding to a region 416 where the vehicle is traveling at a constant speed). The reference signal 430 is cross-correlated with the input signal 432 to generate an output correlation graph 434. The maximum value of the correlation graph 434 is plotted as shown in graph 436. In some embodiments, the (normalized) cross-correlation is calculated by matching the length of the reference vector and the input vector. In some embodiments, the input signal is sampled to have the same length as the reference signal (e.g., a subset of the input signal is selected based on the number of data plots in the reference signal, or vice versa). In some embodiments, the cross-correlation is calculated by shifting the input signal by samples (e.g., 2 milliseconds (ms), 4 ms, 8 ms, or 16 ms).

[0039] In some embodiments, the (normalized) cross-correlation is calculated for each driving state (e.g., constant speed, acceleration, deceleration, and transition between constant speed and acceleration / deceleration). In some cases, the correlation between the constant speed used as reference data and other data is high in other states. In some embodiments, the timing of the change of driving state is calculated from the cross-correlation. In this way, the sensor module described herein can be used to detect braking timing.

[0040] FIG. 4G illustrates an example correlation mapping according to some embodiments. As shown in FIG. 4G, according to some embodiments, input correlation graph 431 is mapped to acceleration state 450, input correlation graph 433 is mapped from acceleration to constant speed state 444, input correlation graph 435 is mapped to constant speed state 448, input correlation graph 437 is mapped from constant speed to deceleration state 442, and input correlation graph 439 is mapped to deceleration state 446. In some embodiments, the constant speed state is used as a reference signal for the correlation mapping. In some embodiments, the boundary of the running state shows a peak where the speed transitions to and from the constant speed state. Graph 460 shows the corresponding waveforms from the sensor module for states 442, 444, 446, 448, and 450.

[0041] FIG. 5A is a block diagram illustrating active control of a brake actuator, according to some embodiments. In FIG. 5A, a brake input signal (e.g., from a brake pedal) is provided to a brake control system, which provides a control signal to activate the brake actuator (to apply the brakes) or deactivate the brake actuator (to release the brakes). In some embodiments, a signal from one or more energy harvesters is provided to the brake control system such that the brake control system provides a modified control signal to the brake actuator. For example, while the brake control system is providing a control signal to the brake actuator (in accordance with a brake input signal indicating that an operator has pressed the brake pedal), the brake control system may receive a signal from one or more energy harvesters indicating that one or more wheels (or tires) are slipping, and modify the control signal provided to the brake actuator to activate anti-lock braking (e.g., provide a pulsed control signal) until the signal indicating slipping is no longer received. In some embodiments, the brake control system receives a signal from each energy harvester at a plurality of wheels (e.g., each wheel) of the vehicle. In some embodiments, the brake control system modifies each wheel individually (eg, applies separate anti-lock braking action at each wheel) based on the corresponding energy harvester signal.

[0042] FIG. 5B is a block diagram illustrating active control of a motor (e.g., an electric motor, a combustion engine, or both), according to some embodiments. In some embodiments, a vehicle driving control system provides a control signal to the motor (e.g., based on a brake input signal and / or an accelerator input signal). In some embodiments, signals from one or more energy harvesters are also provided to the vehicle driving control system, and the vehicle driving control system modifies the control signal provided to the motor based on the signals received from the one or more energy harvesters. For example, the vehicle driving control system adjusts one or more cruise control settings based on the signals received from the one or more energy harvesters. In some embodiments, a vehicle suspension system is adjusted based on signals received from one or more energy harvesters. In some embodiments, a vehicle suspension system is adjusted based on a comparison of respective signals from the energy harvesters on each wheel of the vehicle. For example, vehicle stability and ride comfort are controlled separately based on a particular feedback signal from each wheel. In some embodiments, a vehicle includes multiple motor operations, and each motor operation is adjusted (separately) based on a feedback signal from the wheel. For example, driving control is applied separately to each driving system based on feedback signals from different wheels.

[0043] 6 is a flow diagram illustrating a method 600 for processing signals from one or more sensors mounted adjacent the wheels of a vehicle, according to some embodiments. In some embodiments, method 600 is performed by control circuitry (e.g., one or more processors) mounted to the vehicle. For example, method 600 may be performed by electrical component 140.

[0044] The method 600 includes receiving (610) a first sensor signal and a second sensor signal from one or more sensors (e.g., one or more energy harvesters, vibration sensors, etc.) mounted adjacent to a wheel (e.g., wheel 104) of a vehicle (e.g., vehicle 100).

[0045] In some embodiments, the first sensor signal is from a first sensor of the one or more sensors and the second sensor signal is from a second sensor of the one or more sensors that is different from the first sensor. For example, as described with respect to Figures 3A and 3B, the energy harvesters 106-1 and 106-2 provide separate sensor signals to one or more electrical components 140 (e.g., AFE circuitry 202).

[0046] In some embodiments, the first sensor is located at a first radial direction on the wheel and the second sensor is located at a second radial direction on the wheel that is different from the first radial direction. In some embodiments, the second radial direction is opposite to the first radial direction (e.g., energy harvesters 106-1 and 106-2 of FIG. 3A). In some embodiments, the second radial direction is offset from the first radial direction by an offset angle of at least 15° (e.g., energy harvesters 106-1 and 106-2 of FIG. 3C).

[0047] In some embodiments, the first sensor signal is from a first sensor of the one or more sensors over a first time period and the second sensor signal is from a first sensor of the one or more sensors over a second time period that is different from the first time period. For example, as described with respect to Figures 2A and 2B, the first sensor signal and the second sensor signal are collected by the same sensor (e.g., a single energy harvester 106 shown in Figure 1B) at different times (e.g., t1 and t2).

[0048] The method 600 includes determining 620 a vehicle driving condition (eg, acceleration, deceleration, other vehicle events, road conditions, load distribution, etc.) based on the first sensor signal and the second sensor signal.

[0049] In some embodiments, the method 600 also includes obtaining a superposition of the first sensor signal and the second sensor signal (e.g., the AFE circuitry 202 may be configured to provide the superposition of the first sensor signal and the second sensor signal). Determining the vehicle's running condition based on the first sensor signal and the second sensor signal includes determining the vehicle's running condition based on the superposition of the first sensor signal and the second sensor signal.

[0050] In some embodiments, the method 600 also includes obtaining a difference between the first sensor signal and the second sensor signal (e.g., the AFE circuit 202 may be configured to provide the difference between the first sensor signal and the second sensor signal). Determining the vehicle's running condition based on the first sensor signal and the second sensor signal includes determining the vehicle's running condition based on the difference between the first sensor signal and the second sensor signal.

[0051] In some embodiments, the method 600 also includes providing information indicative of a driving condition of the vehicle. For example, the information indicative of the driving condition may be provided to one or more controllers.

[0052] In some embodiments, the method 600 also includes adjusting operation of the vehicle's brakes according to the determined driving conditions of the vehicle (e.g., by providing information indicative of the driving conditions to a brake control system, as shown in FIG. 5A).

[0053] In some embodiments, the method 600 also includes adjusting operation of the vehicle's motor according to the determined driving condition of the vehicle (e.g., by providing information indicative of the driving condition to a vehicle driving control system, as shown in FIG. 5B).

[0054] (A1) In one aspect, some embodiments include a method (e.g., method 600) for determining a driving state (e.g., driving state and / or road condition) of a vehicle. In some embodiments, the method is performed in a sensor module, a control circuit, and / or one or more processors (e.g., electrical component 140). The method includes (1) receiving a first sensor signal and a second sensor signal from one or more energy harvesting sensors (e.g., energy harvesting device 106) mounted adjacent a wheel (e.g., wheel 104) of the vehicle, and (2) determining the driving state of the vehicle based on the first sensor signal and the second sensor signal.

[0055] (A2) In some embodiments of A1, (i) the first sensor signal is from a first energy harvester (e.g., energy harvesting device 106-1) of the one or more energy harvesting sensors, and (ii) the second sensor signal is from a second energy harvester (e.g., energy harvesting device 106-2) of the one or more energy harvesting sensors, where the second energy harvester is different from the first energy harvester.

[0056] (A3) In some embodiments of A2, (i) the first energy harvester is located in a first radial direction on the wheel, and (ii) the second energy harvester is located in a second radial direction on the wheel, the second radial direction being offset from the first radial direction by an offset angle of at least 15 degrees (e.g., offset by an angle of 180 degrees as illustrated in FIG. 3A).

[0057] (A4) In some embodiments of A1, (i) the first sensor signal is from a first sensor of the one or more energy harvesting sensors over a first period of time, and (ii) the second sensor signal is from the first sensor over a second period of time that is different from the first period of time.

[0058] (A5) In some embodiments of any of A1-A4, the method further includes obtaining a superposition of the first sensor signal and the second sensor signal, and determining the vehicle's running state based on the first sensor signal and the second sensor signal includes determining the vehicle's running state based on the superposition of the first sensor signal and the second sensor signal.

[0059] (A6) In some embodiments of any of A1-A4, the method further includes obtaining a difference between the first sensor signal and the second sensor signal, and determining the running state of the vehicle based on the first sensor signal and the second sensor signal includes determining the running state of the vehicle based on the difference between the first sensor signal and the second sensor signal.

[0060] (A7) In some embodiments of any of A1-A6, the method further includes adjusting operation of brakes of the vehicle depending on the determined driving condition of the vehicle, for example, activation or adjustment of operation of an anti-lock braking system.

[0061] (A8) In some embodiments of any of A1-A7, the method further includes adjusting operation of a motor of the vehicle according to the determined driving conditions of the vehicle, e.g., adjusting operation of a cruise control system based on the determined driving conditions.

[0062] (A9) In some embodiments of any of A1-A8, the method further includes adjusting a vehicle suspension system of the vehicle according to the determined driving condition of the vehicle.

[0063] (A10) In some embodiments of any of A1-A9, the one or more energy harvesting sensors include an energy harvester that includes a cantilever made of a piezoelectric material.

[0064] (A11) In some embodiments of any of A1-A10, determining the vehicle driving state includes identifying one or more of vehicle acceleration, vehicle deceleration, vehicle turning, or vehicle braking.

[0065] (A12) In some embodiments of any of A1-A11, the method further includes (i) receiving a third sensor signal and a fourth sensor signal from one or more energy harvesting sensors mounted adjacent a second wheel of the vehicle, and (ii) determining a second driving state of the vehicle based on a comparison between the first and second sensor signals and the third and fourth sensor signals.

[0066] (A13) In some embodiments of any of A1-A12, the method further includes adjusting operation of a braking system, a motor system, and / or a vehicle suspension system of the vehicle according to a second driving condition of the vehicle.

[0067] In some embodiments, the methods described herein (e.g., methods 600 and A1-A13 above) are performed by a sensor assembly. According to some embodiments, the sensor assembly includes one or more sensors (e.g., one or more energy harvesters 106) mountable adjacent to (e.g., mountable on) the wheels of the vehicle, and one or more processors (e.g., one or more processors 206) electrically coupled to the one or more sensors to determine a driving condition of the vehicle based on the first sensor signal and the second sensor signal.

[0068] In some embodiments, the one or more sensors include an energy harvesting module.

[0069] In some embodiments, the one or more sensors are positioned between the tire bead area and the wheel rim.

[0070] In some embodiments, the one or more sensors include a first sensor for providing a first sensor signal and a second sensor, different from the first sensor, for providing a second sensor signal.

[0071] In some embodiments, the first sensor is located in a first radial direction on the wheel and the second sensor is located in a second radial direction on the wheel, different from the first radial direction.

[0072] In some embodiments, the second radial direction is opposite to the first radial direction.

[0073] In some embodiments, the second radial direction is offset from the first radial direction by an offset angle of at least 15°.

[0074] In some embodiments, the first sensor is disposed adjacent to the first wheel and the second sensor is disposed adjacent to the second wheel, for example, the first sensor is attached (e.g., via clamp 406) to the rim of the first wheel and the second sensor is attached (e.g., via clamp 406) to the rim of the second wheel.

[0075] In some embodiments, the one or more sensors include a first sensor for providing a first sensor signal over a first period of time and a second sensor signal over a second period of time that is different from the first period of time.

[0076] In some embodiments, the sensor assembly also includes a memory for storing at least one of the first sensor signal or the second sensor signal.

[0077] In some embodiments, the one or more processors are configured to obtain a superposition of the first sensor signal and the second sensor signal and determine a driving state of the vehicle based on the superposition of the first sensor signal and the second sensor signal.

[0078] In some embodiments, the one or more processors are configured to obtain a difference between the first sensor signal and the second sensor signal and determine a driving state of the vehicle based on the difference between the first sensor signal and the second sensor signal.

[0079] In some embodiments, the one or more processors are configured to adjust operation of brakes of the vehicle depending on the determined driving conditions of the vehicle.

[0080] In some embodiments, the one or more processors are configured to regulate operation of a motor of the vehicle according to the determined driving condition of the vehicle.

[0081] According to some embodiments, the wheel assembly includes a wheel and any sensor assembly described herein, where the sensor assembly is mounted adjacent to the wheel (e.g., the sensor assembly is mounted on the wheel).

[0082] It will also be understood that, although terms such as first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first cantilever can be referred to as a second cantilever, and similarly, a second cantilever can be referred to as a first cantilever, without departing from the scope of the various described embodiments. The first cantilever and the second cantilever are both cantilevers, but are not the same cantilever.

[0083] The terminology used in the description of the embodiments herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of the claims. As used in the description and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly dictates otherwise. It will also be understood that the term "and / or" as used herein refers to and includes any and all possible combinations of one or more of the associated listed items. It will also be understood that the terms "comprises" and / or "comprising" as used herein specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0084] For purposes of explanation, the foregoing description has been described with reference to specific embodiments. However, the illustrative discussion above is not intended to be exhaustive or to limit the scope of the claims to the precise forms disclosed. Many modifications and variations are possible in light of the above teachings. The embodiments have been selected and described in order to best explain the principles and practical applications of the various described embodiments, so as to enable others skilled in the art to best utilize the principles and various modifications suited to the particular applications contemplated.

Claims

Receiving a first sensor signal and a second sensor signal from one or more energy harvesting sensors attached adjacent to a wheel of a vehicle; Generating a differential waveform by superimposing the first sensor signal and the second sensor signal; Generating a cross-correlation by cross-correlating the differential waveform with a reference waveform corresponding to a steady driving state; Determining a driving state of the vehicle based on a maximum value of the cross-correlation; Generating a signal indicating the determined driving state based on the determined driving state, the method comprising:

2. The first sensor signal is from a first energy harvester among the one or more energy harvesting sensors, The second sensor signal is from a second energy harvester among the one or more energy harvesting sensors, and the second energy harvester is different from the first energy harvester, the method according to claim 1.

3. The first energy harvester is located in a first radial direction on the wheel, The second energy harvester is located in a second radial direction on the wheel, and the second radial direction is offset from the first radial direction by an offset angle of at least 15°, the method according to claim 2.

4. The first sensor signal is from a first sensor among the one or more energy harvesting sensors over a first period, The second sensor signal is from the first sensor over a second period different from the first period, the method according to claim 1.

5. The method according to claim 1, further comprising adjusting an operation of a brake of the vehicle by receiving the signal indicating the determined driving state of the vehicle.

6. The method according to claim 1, further comprising adjusting an operation of a motor of the vehicle by receiving the signal indicating the determined driving state of the vehicle.

7. The method according to claim 1, wherein the one or more energy harvesting sensors comprise an energy harvester comprising a cantilever made of a piezoelectric material.

8. The method according to claim 1, wherein determining the driving state of the vehicle includes identifying one or more of acceleration of the vehicle, deceleration of the vehicle, turning of the vehicle, or braking of the vehicle. **Claim 9** The method according to claim 1, wherein the cross-correlation is generated based on a driving state of the vehicle. **Claim 10** The method according to claim 1, wherein determining the driving state includes identifying a change in state in the driving state of the vehicle. **Claim 11** One or more energy harvesting sensors attachable to a wheel of a vehicle, an electrical component disposed inside the wheel of the vehicle or a tire on the wheel and electrically connected to the one or more energy harvesting sensors, a sensor assembly comprising: the electrical component is for obtaining the first sensor signal and the second sensor signal from one or more energy harvesting sensors for providing a first sensor signal over a first period and a second sensor signal over a second period different from the first period; generating a differential waveform by superimposing the first sensor signal and the second sensor signal; generating a cross-correlation by cross-correlating the differential waveform with a reference waveform corresponding to a steady driving state; determining the driving state of the vehicle based on a maximum value of the cross-correlation; generating a signal indicating the determined driving state based on the determined driving state; and comprising a circuit configured for the sensor assembly. **Claim 12** The sensor assembly according to claim 11, wherein the one or more energy harvesting sensors are attachable between a tire bead area and a rim of the wheel. **Claim 13** The sensor assembly according to claim 11, wherein the one or more energy harvesting sensors include a first sensor for providing the first sensor signal and a second sensor different from the first sensor for providing the second sensor signal. **Claim 14** The sensor assembly according to claim 13, wherein the sensor assembly is configured to have the first sensor located in a first radial direction on the wheel and the second sensor located in a second radial direction, and the second radial direction is offset from the first radial direction by an offset angle of at least 15°.

15. The sensor assembly according to claim 11, further comprising a memory for storing at least one of the first sensor signal or the second sensor signal.

16. The sensor assembly according to claim 11, wherein the circuit is further configured to adjust the operation of the brake of the vehicle by receiving the signal indicating the determined driving state of the vehicle.

17. The sensor assembly according to claim 11, wherein the circuit is further configured to adjust the operation of the motor of the vehicle by receiving the signal indicating the determined driving state of the vehicle.

18. The sensor assembly according to claim 11, wherein the cross-correlation is generated based on a driving state of the vehicle.

19. The sensor assembly according to claim 11, wherein determining the driving state includes identifying a change in state in the driving state of the vehicle.

20. The sensor assembly according to claim 11, wherein the circuit includes an analog front end (AFE) circuit configured to acquire the first sensor signal and the second sensor signal and generate the differential waveform.

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