Method for determining vibrational anomalies of a vehicle
11480491 · 2022-10-25
Assignee
Inventors
- Eric L. Canfield (Downingtown, PA, US)
- Robert P. Alston (Exton, PA, US)
- David M. Scribner (Viera, FL, US)
- Melody Gao (Downingtown, PA, US)
- Andrew Babala (Glenmoore, PA, US)
- Kevin Codd (Downingtown, PA, US)
- David A. Fenimore (Coatesville, PA, US)
- Ryan Mendenhall (Coatesville, PA, US)
- Kavish V. Sani (Chester Springs, PA, US)
- Rishi Kumar (Downingtown, PA, US)
- Savar R. Amin (Malvern, PA, US)
- Pablo A. Rodriguez (South Coatesville, PA, US)
Cpc classification
International classification
Abstract
A method is disclosed for determining vibrational anomalies of a vehicle. An object is removably attached to a wheel of the vehicle in a manner that inhibits the object from coming off of the vehicle when the vehicle is in operation. The object includes one or more inertial measurement units (IMU's) mounted to the object and configured to measure parameters that are used for calculating the vibrational anomalies when the vehicle is in operation. Motion data captured by the one or more IMU's is collected. The collected motion data is processed to determine the presence of one or more vibrational anomalies of the vehicle. A recommended corrective action to be taken is determined when the result of the processed data indicates the presence of one or more vibrational anomalies of the vehicle.
Claims
1. A method for determining vibrational anomalies of a vehicle comprising: (a) removably attaching an object to a wheel of the vehicle in a manner that inhibits the object from coming off of the vehicle when the vehicle is in operation, wherein the object is removably attached to a tire/hub assembly of the wheel of the vehicle via lug nuts of the tire/hub assembly by fitting portions of the object over the lug nuts of the tire/hub assembly, thereby removably attaching the object to the tire/hub assembly of the wheel of the vehicle without requiring removal of any lug nuts of the tire/hub assembly, the object including one or more inertial measurement units (IMU's) mounted to the object and configured to measure parameters that are used for calculating the vibrational anomalies when the vehicle is in operation; (b) collecting motion data captured by the one or more IMU's; (c) processing the collected motion data to determine the presence of one or more vibrational anomalies of the vehicle; and (d) determining a recommended corrective action to be taken when the result of the processed data indicates the presence of one or more vibrational anomalies of the vehicle.
2. The method of claim 1 wherein the vehicle is a motor vehicle or an electric vehicle, and the determined vibrational anomaly is caused by lateral force variation, and the recommended corrective action is one or more of (i) resetting lug nuts of the wheel, or (ii) inspecting the wheel's rim for potential bent regions.
3. The method of claim 1 wherein the vehicle is a motor vehicle or an electric vehicle, and the determined vibrational anomaly is caused by radial force variation, and the recommended corrective action is one or more of (i) inspecting the wheel's tire for excessive debris and removing any debris, or (ii) inspecting the wheel's tire for excessive wear in a single location and replacing the tire of the wheel when excessive wear in a single location is located, or (iii) attaching a mass at a predefined location designated by the application of the wheel's tire.
4. The method of claim 1 wherein step (c) further comprises further determining the magnitude and location of the source of the one or more vibrational anomalies of the vehicle.
5. A method for determining vibrational anomalies of a tire/hub assembly that is removably mounted to a spindle of a tire balancing machine, the method comprising: (a) removably attaching an object on the spindle of the tire balancing machine adjacent to the tire/hub assembly that has been previously mounted to the spindle of a tire balancing machine, the object including one or more inertial measurement units (IMU's) mounted to the object and configured to measure parameters that are used for calculating the vibrational anomalies of the tire/hub assembly during operation of the tire balancing machine; (b) collecting motion data captured by the one or more IMU's; (c) processing the collected motion data to determine the presence of one or more vibrational anomalies of the vehicle; and (d) determining a corrective action to be taken when the result of the processed data indicates the presence of one or more vibrational anomalies of the tire/hub assembly.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawings will be provided by the Office upon request and payment of the necessary fee.
(2) Preferred embodiments of the present invention will now be described by way of example with reference to the accompanying drawings:
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DETAILED DESCRIPTION OF THE INVENTION
(18) Certain terminology is used herein for convenience only and is not to be taken as a limitation on the present invention.
(19) The words “a” and “an”, as used in the claims and in the corresponding portions of the specification, mean “at least one.”
(20) The discussion below refers to “vibrations” and “translational vibrations.” Some vibrations are the result of translational forces, whereas other vibrations are not the result of translational forces. One type of translational vibration is “imbalance forces.” The present invention determines the presence of one or more “vibrational anomalies.” In one embodiment, the vibrational anomaly or anomalies are those of a vehicle. In another embodiment, the vibrational anomaly or anomalies are those of a tire/hub assembly.
(21) The discussion below also refers to a vehicle being “in operation.” For a passenger vehicle or truck (e.g., a motor vehicle, an electric vehicle (EV)), “in operation” includes having the vehicle in motion or having the vehicle's engine on (in the case of a motor vehicle), but not necessarily having the vehicle in motion. For other types of vehicles, such as railcars, being “in operation” requires having the vehicle in motion.
(22) The various embodiments described below each make use of one or more IMU's. Any IMU may be used that has a form factor and durability suitable for the environment described herein. One suitable IMU is the IMU described in U.S. Pat. No. 10,284,752 (Canfield et al.), which is incorporated herein by reference. Sample measured parameters, which are used for calculating the imbalance forces during motion of the vehicle, are captured by one or more IMU's. These parameters include, but are not limited to, linear acceleration and angular velocity.
(23) I. Determination of Vibrational Anomalies of a Vehicle
(24) One preferred embodiment of the present invention determines vibrational anomalies of a vehicle using the following process:
(25) 1. An object is removably attached to a wheel of the vehicle in a manner that inhibits the object from coming off the vehicle when the vehicle is in operation. The object includes one or more IMU's mounted to the object and configured to measure parameters that are used for calculating the vibrational anomalies when the vehicle is in operation. One suitable object is any one of the apparatuses shown in U.S. Pat. No. 10,969,292. In these embodiments, the object is removably attached to a tire/hub assembly of the wheel of the vehicle via lug nuts of the tire/hub assembly. However, other objects and attachment mechanisms are within the scope of the present invention. The object is also interchangeably referred to herein as “device.”
(26) 2. Collect motion data captured by the one or more IMU's. One example of collected motion data is shown in
(27) i. linear acceleration (measured by an accelerometer) in all three axes (x, y, and z),
(28) ii. angular velocity (measured by a gyroscope) in all three axes (interchangeably referred to herein as “AngVel” and “gyro”),
(29) iii. magnetic field strength (measured by a magnetometer) in all three axes.
(30) The motion data is originally displayed in bit count (a value from 0-65536) in 9 columns, as shown in
(31) 3. The collected motion data is processed to determine the presence of one or more vibrational anomalies of the vehicle. In one embodiment, this involves determining the magnitude and location of the one or more vibrational anomalies of the vehicle.
(32) 4. A recommended corrective action to be taken is determined when the result of the processed data indicates the presence of one or more vibrational anomalies of the vehicle.
(33) A. Vibrational Anomaly is Caused by Lateral Force Variation
(34) In one preferred embodiment wherein, the vehicle is a motor vehicle or an electric vehicle, the determined vibrational anomaly may be caused by lateral force variation. If so, examples of the recommended corrective action include resetting lug nuts of the wheel or inspecting the wheel's rim for potential bent regions.
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(36) 205 Run Test according to Steps in the Data Collection Process
(37) 1) Locate a road that allows the vehicle to attain the top speed needed for the trial and slow to a stop safely. 2) Prepare Device with trial parameters. These parameters include data collection rate, sensor sensitivity and filter cutoff. 3) Insert Device into Platen. 4) Affix Platen to tire. 5) Pull vehicle into its starting position and come to rest. 6) Begin Data Acquisition. 7) Accelerate steadily to a speed of 15 mph. 8) Maintain that speed for 4 seconds. 9) Accelerate to the speed at which the quality of ride issue arises. 10) Release the accelerator and continue in a straight line on a level, smooth road for at least 4 seconds. 11) Slow to a stop. 12) Stop Data Acquisition. 13) Download data onto computer.
210 Format Data—Create a one-to-one relationship between time and the corresponding data. For an application such as Excel, this would involve formatting the data into columns (time, accel x, accel y, . . . gyro x . . . ). For an application such as a Python script this returns a Pandas DataFrame.
215 Set parameters for filters a. Period is equal to 1/sample rate b. Cutoff frequency for low-pass filter used in Step 225 c. Find data range to be used i. Load data into Dashboard graph (from BFA website) ii. View AngVelX (angular velocity along the x-axis) iii. Find section where AngVelX is relatively constant
220 Apply moving average (smoothing)
225 Apply low pass filter—One example utilizes scipy.signal in Python
230 Do Peak Analysis a. Find peaks—One example utilizes scipy.signal.find_peaks( ) with a distance parameter multiplied by 0.7 This locates the peaks of the signal. The same can be done for the relative minimum values. These values are stored in a max/min array. b. Returns location (time/data point−x only) of peaks c. Repeat a and b for the troughs
(38) The result of this process returns the data points for each peak and each trough that are marked by small x's in
(39) 235 Period analysis—This determines the period between each pair of peaks and each pair of troughs. This array can be used to find the period by determining the difference in time (x distance) between adjacent relative maxima and relative minima.
(40) 240 Determine the standard deviation of the periods found in step 235.
(41) a. If std(period)≥0.035, 245 there is no Lateral Force Variation. “std(period)” is the standard deviation of all of the periods found during Period analysis (step 235) b. If std(period)<0.035, 250 determine corrective action
255 Amplitude analysis a. Find the amplitude of each peak/trough pair using:
(crest y value−following trough y value)/2 b. Find average and standard deviation. In one embodiment the Python Functions .mean( ) and .std( ) are used.
260 Eliminate outliers using z-score
(42) a.
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265 Calculate angle offset using
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280 Determine if lug nuts are seated properly a. If not, 285 reset lug nuts b. If yes, go to next step
290 Determine if the rim is bent a. If not, 295 see professional b. If yes, 297 straighten rim
(45) Referring to 230 Peak Analysis of
(46) Referring to
(47) As shown in
(48) Referring to 255 Amplitude Analysis in
(49) B. Vibrational Anomaly is Caused by Radial Force Variation
(50) In one preferred embodiment wherein the vehicle is a motor vehicle or an electric vehicle, the determined vibrational anomaly may be caused by radial force variation. If so, examples of the recommended corrective action include inspecting the wheel's tire for excessive debris and removing any debris or inspecting the wheel's tire for excessive wear in a single location and replacing the tire of the wheel when excessive wear in a single location is located or attaching a mass at a predefined location designated by the application of the wheel's tire.
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(52) 305 Run Test according to Steps in the Data Collection Process
(53) 1) Locate a road that allows the vehicle to attain the top speed needed for the trial and slow to a stop safely. 2) Prepare Device with trial parameters. These parameters include data collection rate, sensor sensitivity and filter cutoff. 3) Insert Device into Platen. 4) Affix Platen to tire. 5) Pull vehicle into its starting position and come to rest. 6) Begin Data Acquisition. 7) Accelerate steadily to a speed of 15 mph. 8) Maintain that speed for 4 seconds. 9) Accelerate to the speed at which the quality of ride issue arises. 10) Release the accelerator and continue in a straight line on a level, smooth road for at least 4 seconds. 11) Slow to a stop. 12) Stop Data Acquisition. 13) Download data onto computer.
310 Format Data—Create a one-to-one relationship between time and the corresponding data. For an application such as Excel, this would involve formatting the data into columns (time, accel x, accel y, . . . gyro x . . . ), and returning a data frame. This adds a time column.
315 Set parameters for filters—Period is equal to 1/sample rate
320 Perform a Spectrogram of AccelX—Use a Short-Time Fourier Transformation to determine the range of data to be used for further analysis which is all accomplished by a script a. Convert Spectrogram to a computer readable greyscale image. An example of the image produced in this step is shown in
335 Utilize an EMD function a. Import selected data from the Spectrogram. b. Run EMD script—this script will output the standard deviation between the first mode and the original data. (Each mode represents a component of the signal. The first mode will be the normal oscillation of the x-axis without radial force variation.)
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(56) 340 Determine the difference in standard deviation between the original data and the first mode
(57) a. If the difference ≤0.3, 345 there is no imbalance. Check road surface or vehicle for other issues. b. If the difference >0.3, 350 determine corrective action
355 Utilize a CEEMDAN Function (CEEMDAN: Complete Ensemble Empirical Mode Decomposition with Adaptive Noise)
360 Analyze location of deviation within the cycle a. Take second derivative of filtered data to identify inflection points. b. Find inflection points which differ from main signal inflection points. These additional inflection points come from the anomaly and are circled in
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365 Determine expected waveform according to tire specifications—Period is determined by tire circumference and vehicle speed.
370 Compare to raw data
375 Determine if the difference in amplitude is significant a. If not, 280 not correction is needed b. If yes, 385 use difference to calculate mass i. The magnitude of the imbalance will be related to the amplitude of the signal created by the imbalance. The greater the imbalance, the greater the amplitude of the signal. Therefore, the mass needed to correct the imbalance can be found using this amplitude. ii. The difference in amplitude multiplied by the mass of wheel assembly is equal to the centripetal force acting on the corrective mass. iii. The mass of the corrective weight is equal to
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390 Place mass on tire at calculated angle
II. Determination of Vibrational Anomalies of a Tire/Hub Assembly Using a Tire Balancing Machine
(61) In another preferred embodiment of the present invention, which is described with respect to
(62) 1. An object (device) is attached on a spindle of a tire balancing machine adjacent to the tire/hub assembly that has been previously mounted to the spindle of a tire balancing machine. The object includes one or more IMU's mounted to the object and configured to measure parameters that are used for calculating the vibrational anomalies of the tire/hub assembly during operation of the tire balancing machine. The object in this embodiment differs from the object in the previous embodiment, except for the IMU-related structure.
(63) 2. Motion data captured by the one or more IMU's are collected.
(64) 3. The collected motion data are processed to determine the presence of one or more vibrational anomalies of the vehicle.
(65) 4. A determination is made of a corrective action to be taken when the result of the processed data indicates the presence of one or more vibrational anomalies of the tire/hub assembly.
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(70) One suitable wheel balancer is a Hunter Road Force® Elite Wheel Balancer. However, other wheel balancers may be used.
(71) Referring to
(72) 100—machine screws
(73) 1. In one suitable application, 10-32×1 inch screws may be used. 2. The screws pass through module holder 110 and adapter 120 to go into T-handle 130. a. The holes 140 in the module holder 110 and the holes 150 in the adapter 120 are large enough for the screw 100 to pass through without turning the screw 100. b. The holes 160 in the T-handle 130 are large enough so that the screw 100 must be turned in order to insert the screw 100 into the hole 160.
110—module holder. In one suitable embodiment, this part is similar to the corresponding part in U.S. Pat. No. 10,969,292, shown in
120—adapter 1. This part acts as an interface between the module holder 110 and the T-handle 130. 2. Flat on top to fit the bottom of the module holder 3. Contoured on the bottom to match the top of the T-handle 130. 4.
530—T-handle 130 1. In one suitable embodiment, this element may be a Yosoo Wheel Balancer Kit (Amazon ASIN #B08R9PCHZT) having the following dimensions: Size (L×W×H): Approx. 28×12×14.5 cm/11.0×4.7×5.7 in The Top Head Diameter: 8.5 cm/3.3″ Thread Diameter: 38 mm/1.5″ Screw Pitch: 3 mm/0.12″ 2. Holes drilled to match holes in adapter 120
This assembly is used to attach an IMU to the spindle of the wheel balancer. The wheel 400 (interchangeably referred to herein as a “tire/hub assembly”) is secured to the spindle 410 on the wheel balancer as it is normally done with the collet 405 and provided T-handle 420. Device 430 is then threaded onto the spindle 410 as shown in
(74) When fully assembled, all the components appear as shown in
(75) The procedure used to balance a wheel is followed while the IMU collects data. That data can then be used to verify the information provided by the wheel balancer.
(76) Referring again to
(77) The tire balancing machine is then operated in its normal manner, and motion data captured by the IMU is collected and processed as described above.
(78) III. Additional Considerations
(79) A. IMU Calculation
(80) Depending upon processing capacity and software/hardware architecture considerations, calculations of data collected by the IMU may be processed internally within the IMU, external to the IMU (e.g., exported to a cloud service such as AWS), or a combination thereof.
(81) B. Feedback During Testing
(82) In one embodiment, the operator of the vehicle in motion is provided with real-time information that improves the quality of the data collection. For example, at a certain point in the testing process, the operator may be informed to drive at a constant speed for a particular duration of time. The IMU may perform internal calculations which are used for the feedback.
(83) C. Vehicle Speed Data One suitable method for obtaining vehicle speed data is via the On-board diagnostics (OBD) port of the vehicle.
(84) D. Deployment Implementation Features
(85) The use of the device, when deployed as a product, may differ from what is disclosed by way of example herein. For example, data collection preferably begins automatically once the vehicle is determined to be in operation; data collection may occur for an indefinite period of time; later data analysis may be used to determine such parameters as constant speed, acceleration, travel direction (e.g., straight, rounding a curve, uphill, downhill); sequential or analytic determination can be made of one or more vibrational anomalies; feedback to the driver may occur to request certain maneuvers, speeds, and the like.
(86) E. Other Vibrational Anomalies
(87) One skilled in the art would recognize that vibrational anomalies caused by other sources including, but not limited to back firing and worn bearings could be detected by this apparatus.
(88) It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments disclosed, but it is intended to cover modifications within the spirit and scope of the present invention.