Intermittent detector for power group resistance

Abstract

A method for detecting degeneration intermittency in an electrical connection in a steering system of a vehicle includes using a processor configured to execute instructions: receiving an input indicative of a plurality of measurements of a resistance associated with the electrical connection; calculating at least one adaptive control threshold based on the received input; comparing a first measurement result of the plurality of measurement results with the at least one adaptive control threshold; determining whether the electrical connection has degradation intermittency in response to a comparison between the first measurement and the at least one adaptive control threshold; and performing at least one action in response to determining that the electrical connection has degradation intermittency.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 542,437, filed on October 4, 2023. The entire disclosures of the above-referenced applications are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to systems and methods for monitoring the health of a connection between a power source and an electric power steering (EPS) system. Background Art

[0004] Vehicles (such as cars, trucks, sport utility vehicles, crossovers, minivans, boats, aircraft, all-terrain vehicles, recreational vehicles, or other suitable forms of transportation) typically include a steering system, such as an electric power steering (EPS) system, a steer-by-wire (SbW) steering system, a hydraulic steering system, or other suitable steering system. The steering system of such a vehicle typically controls various aspects of the vehicle's steering, including providing steering assistance to the operator of the vehicle, controlling the vehicle's steering wheel, etc. Summary of the invention

[0005] The present disclosure generally relates to determining the health of electrical connections in a steering system of a vehicle.

[0006] In an example, a method for detecting degradation intermittency in an electrical connection in a steering system of a vehicle includes: using a processor configured to execute instructions; receiving an input indicating multiple measurements of resistance associated with the electrical connection; calculating at least one adaptive control threshold based on the received input; comparing a first measurement of the multiple measurements with the at least one adaptive control threshold; determining whether the electrical connection has degradation intermittency in response to the comparison between the first measurement and the at least one adaptive control threshold; and, in response to determining that the electrical connection has degradation intermittent, performing at least one action.

[0007] Other aspects of the disclosed embodiments include systems configured to perform the steps and functions of the described methods.

[0008] These and other aspects of the present disclosure are disclosed in the following detailed description of the embodiments, the appended claims and the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The present disclosure is best understood from the following detailed description when read in conjunction with the accompanying drawings. It should be emphasized that, in accordance with conventional practice, the various features of the drawings are not drawn to scale. Instead, the sizes of the various features are arbitrarily enlarged or reduced for clarity.

[0010] Figure 1A A vehicle in accordance with the principles of the present disclosure is generally shown.

[0011] Figure 1B A controller according to the principles of the present disclosure is generally shown.

[0012] Figure 2 An example electric power steering (EPS) system according to the principles of the present disclosure is generally shown schematically.

[0013] Figure 3 Example degradation of an electrical connection during its useful life is generally shown.

[0014] Figure 4 Example sample measurements or calculations indicative of intermittent degradation and non-intermittent degradation are generally shown.

[0015] FIG. 5A to FIG. 5F Example sample measurements relative to various control thresholds in accordance with the principles of the present disclosure are generally shown.

[0016] Figure 6 is a flow chart generally illustrating the steps of an example method for detecting degradation intermittency according to the principles of the present disclosure. DETAILED DESCRIPTION

[0017] The following discussion is directed to various embodiments of the present disclosure. Although one or more of these embodiments may be preferred, the disclosed embodiments should not be interpreted or otherwise used to limit the scope of the present disclosure (including the claims). In addition, it will be understood by those skilled in the art that the following description has a wide range of applications, and the discussion of any embodiment is only meant as an example of that embodiment, and is not intended to imply that the scope of the present disclosure (including the claims) is limited to that embodiment.

[0018] As described, a vehicle (such as a car, truck, sport utility vehicle, crossover, minivan, boat, aircraft, all-terrain vehicle, recreational vehicle, or other suitable form of transportation) typically includes a steering system, such as an electric power steering (EPS) system, a steer-by-wire (SbW) steering system, a hydraulic steering system, or other suitable steering system. The steering system of such a vehicle typically controls various aspects of the vehicle's steering, including providing steering assistance to the operator of the vehicle, controlling the vehicle's steering wheel, etc. Although described herein with respect to a vehicle, the principles of the present disclosure may also be implemented in other types of transportation or non-transportation devices that include a steering system.

[0019] Vehicles typically include one or more motors, such as electric motors configured to control various aspects of the steering system of the vehicle. A path for providing power from a vehicle power source (e.g., battery, alternator, power supply) to a motor controller or one or more motors of the steering system can be provided. The path may include one or more wiring harnesses, wires, connectors, terminals, fuses, or other (e.g., non-traditional) paths for conducting current, such as chassis grounding, busbars, through engine blocks, etc. Anything that can provide a sufficiently low impedance path (high power connection) for energy transfer can be used to provide power to or from the motor controller. High-power electrical harnesses and connectors can supply electrical power from the vehicle electrical system (e.g., battery and / or alternator) to the motor controller of one or more motors of the steering system. During the life of the vehicle, the high-power connection properties may degrade, resulting in the eventual inability to provide enough input power to deliver the desired electromechanical output power to provide steering assistance or steering angle functions. This degradation can be observed as an effective increase in the resistance of the power connector or harness. When attempting to deliver this electromechanical output power, the power supply current draw through the increased resistance of the high power connection or wiring harness will result in a large voltage drop between the vehicle power supply and the motor controller, which can cause the total voltage at the motor controller input to be low enough to cause a "shutdown" or "drop from operating state", which can result in loss of functionality, such as loss of assist in an EPS system and / or loss of angle control in an advanced driver assistance system (ADAS) or SbW system. In some examples, even if the motor controller input is not shut down, the reduced available power can result in lower torque assist, laggy response, poor feedback, reduced angle control, and overall reduced steering performance.

[0020] In some embodiments, it is desirable to detect the degradation condition and / or limit the electromechanical output power command based on the detection of the degradation condition in order to reduce the required input power and prevent loss of functionality of the steering system, such as loss of assistance in an EPS system or loss of angle control in an ADAS or SbW system. Although performance may be reduced, this is preferable to alternatives, which may include complete loss of assistance or angle control functionality.

[0021] Some systems may implement techniques for determining degradation of an input power connection (or harness) using available signals within existing control modules and software. An example system for determining power connection degradation is described in more detail in U.S. Patent Application No. 17 / 733,434, filed on April 29, 2022, the entire contents of which are incorporated herein by reference. In this example, electric power is applied to the motor phase and the response is measured. The applied power is V*I, where V and I are the vector quantities of the applied motor voltage and the vector quantities of the motor current, respectively. In some examples, the applied electric power is selected to produce zero motor torque. For example, for an EPS system, a sinusoidal, non-torque-producing current is applied to the motor phase. For ADAS and SbW systems, a sinusoidal, non-torque-producing or torque-producing current may be applied. The measurement of the response (e.g., a drop or change in voltage, such as a drop or change in voltage at the bridge voltage of an inverter or the input of a control module) indicates degradation and a state of health (SOH) of the input power connection.

[0022] In some examples, detectable degradation generally increases over time (e.g., exponentially, linearly, etc.). For example, a measurement of a representative resistance (e.g., a resistance associated with a power connector or wiring harness as described above) may generally increase over time as degradation increases. However, in some examples, the characteristic or behavior corresponding to degradation is intermittent. For example, one or more measurements indicating degradation may appear randomly, with the measurements intermittently increasing and decreasing (e.g., due to micro-wear, arcing, etc.) rather than generally increasing over time. Thus, a first resistance measurement may indicate that degradation above a certain threshold (e.g., a critical resistance) has occurred, while a subsequent second resistance measurement indicates that degradation is less than the threshold.

[0023] Thus, intermittency detection systems and methods according to the present disclosure are configured to accurately detect degradation intermittency, as described in more detail below.

[0024] Furthermore, although described with respect to steering systems, the principles of the present disclosure may be implemented in other types of vehicular or non-vehicular systems that include motors and actuators (eg, windshield wiper systems, propulsion systems, window controls, etc.).

[0025] Figure 1AA vehicle 10 in accordance with the principles of the present disclosure is generally shown. The vehicle 10 may include any suitable vehicle, such as a car, a truck, a sport utility vehicle, a minivan, a crossover, any other passenger vehicle, any suitable commercial vehicle, or any other suitable vehicle. Although the vehicle 10 is shown as a passenger vehicle having wheels and for use on roads, the principles of the present disclosure may be applied to other vehicles, such as airplanes, boats, trains, drones, or other suitable vehicles.

[0026] The vehicle 10 includes a vehicle body 12 and a hood 14. A passenger compartment 18 is at least partially defined by the vehicle body 12. Another portion of the vehicle body 12 defines an engine compartment 20. The hood 14 may be movably attached to a portion of the vehicle body 12 such that when the hood 14 is in a first position, or open position, the hood 14 provides access to the engine compartment 20, and when the hood 14 is in a second position, or closed position, the hood 14 covers the engine compartment 20. In some embodiments, the engine compartment 20 may be disposed at the rear of the vehicle 10, rather than as generally shown.

[0027] The passenger compartment 18 may be disposed rearward of the engine compartment 20, but in embodiments where the engine compartment 20 is disposed at the rear of the vehicle 10, the passenger compartment 18 may be disposed forward of the engine compartment 20. The vehicle 10 may include any suitable propulsion system, including: an internal combustion engine; one or more electric motors (e.g., for an electric vehicle); one or more fuel cells; a hybrid propulsion system including a combination of an internal combustion engine and one or more electric motors (e.g., for a hybrid vehicle); and / or any other suitable propulsion system.

[0028] In some embodiments, the vehicle 10 may include a petrol or gasoline fuel engine, such as a spark ignition engine. In some embodiments, the vehicle 10 may include a diesel fuel engine, such as a compression ignition engine. The engine compartment 20 accommodates and / or encloses at least some components of the propulsion system of the vehicle 10. Additionally or alternatively, a propulsion controller (such as an accelerator actuator (e.g., an accelerator pedal), a brake actuator (e.g., a brake pedal), a steering wheel, and other such components) are disposed in the passenger compartment 18 of the vehicle 10. The propulsion controller may be actuated or controlled by an operator of the vehicle 10, and the propulsion controller may be directly connected to corresponding components of the propulsion system, such as a throttle, a brake, a vehicle axle, a vehicle transmission, etc., respectively. In some embodiments, the propulsion controller may transmit a signal to a vehicle computer (e.g., via a drive-by-wire), which in turn may control corresponding propulsion components of the propulsion system. Therefore, in some embodiments, the vehicle 10 may be an autonomous vehicle.

[0029] In some embodiments, the vehicle 10 includes a transmission that is connected to the crankshaft via a flywheel or a clutch or a fluid coupling. In some embodiments, the transmission includes a manual transmission. In some embodiments, the transmission includes an automatic transmission. In the case of an internal combustion engine or a hybrid vehicle, the vehicle 10 may include one or more pistons that operate in conjunction with the crankshaft to generate a force that is transmitted through the transmission to rotate one or more shafts of the wheel 22. When the vehicle 10 includes one or more electric motors, the vehicle battery and / or fuel cell provides energy to the electric motor to rotate the wheel 22.

[0030] The vehicle 10 may include an automatic vehicle propulsion system, such as cruise control, adaptive cruise control, automatic braking control, other automatic vehicle propulsion systems, or combinations thereof. The vehicle 10 may be an autonomous or semi-autonomous vehicle, or other suitable type of vehicle. The vehicle 10 may include more or fewer features than generally shown and / or disclosed herein.

[0031] In some embodiments, the vehicle 10 may include an Ethernet component 24, a controller area network (CAN) bus 26, a media oriented system transport component (MOST) 28, a FlexRay component 30 (e.g., a wire control brake system, etc.), and a local interconnect network component (LIN) 32. The vehicle 10 may use the CAN bus 26, the MOST 28, the FlexRay component 30, the LIN 32, other suitable networks or communication systems, or a combination thereof to transmit various information from sensors, such as those inside or outside the vehicle, to various processors or controllers, such as those inside or outside the vehicle. The vehicle 10 may include more or fewer features than those generally shown and / or disclosed herein.

[0032] In some embodiments, although not shown, the vehicle 10 may include a steering system, such as an EPS system, a steer-by-wire steering system (e.g., which may include or communicate with one or more controllers that control components of the steering system without using a mechanical connection between a steering wheel and the wheels 22 of the vehicle 10), a hydraulic steering system (e.g., which may include a magnetic actuator incorporated into a valve assembly of the hydraulic steering system), or other suitable steering systems.

[0033] The steering system may include an open-loop feedback control system or mechanism, a closed-loop feedback control system or mechanism, or a combination thereof. The steering system may be configured to receive various inputs, including, but not limited to, steering wheel position, input torque, one or more road wheel positions, vehicle speed, temperature, other suitable inputs or information (such as any signal available on a vehicle communication bus), or a combination thereof.

[0034] Additionally or alternatively, the input may include steering wheel torque, steering wheel angle, motor speed, vehicle speed, estimated motor torque command, other suitable inputs, or combinations thereof. The steering system may be configured to provide steering functionality and / or control to the vehicle 10. For example, the steering system may generate an assist torque based on various inputs. The steering system may be configured to use the assist torque to selectively control the motor of the steering system to provide steering assistance to the operator of the vehicle 10. The steering system of the present disclosure is configured to implement an intermittent detection system and method, as described in more detail below.

[0035] In some embodiments, vehicle 10 may include a controller, such as Figure 1B100 is generally shown in FIG. 100. The controller 100 may include any suitable controller, such as an electronic control unit or other suitable controller. The controller 100 may be configured to control various functions of, for example, a steering system and / or various functions of the vehicle 10. The controller 100 may include a processor 102 and a memory 104. The processor 102 may include any suitable processor, such as the processor described herein. Additionally or alternatively, the controller 100 may include any suitable number of processors as a supplement or alternative to the processor 102. The memory 104 may include a single disk or multiple disks (e.g., a hard disk drive), and include a storage management module that manages one or more partitions within the memory 104. In some embodiments, the memory 104 may include a flash memory, a semiconductor (solid-state) memory, etc. The memory 104 may include a random access memory (RAM), a read-only memory (ROM), or a combination thereof. The memory 104 may include instructions that, when executed by the processor 102, cause the processor 102 to control at least various aspects of the vehicle 10. Additionally or alternatively, the memory 104 may include instructions that, when executed by the processor 102, cause the processor 102 to perform functions associated with the systems and methods described herein.

[0036] The controller 100 may receive one or more signals indicating the sensed or measured characteristics of the vehicle 10 from various measuring devices or sensors 106. The sensor 106 may include any suitable sensor, measuring device and / or other suitable mechanism. For example, the sensor 106 may include one or more torque sensors or devices, one or more steering wheel position sensors or devices, one or more motor position sensors or devices, one or more position sensors or devices, other suitable sensors or devices, or a combination thereof. One or more signals may indicate steering wheel torque, steering wheel angle, motor speed, vehicle speed, other suitable information, or a combination thereof. As used herein, a "sensor" may correspond to a physical sensor or a derived signal (e.g., a signal derived from an algorithm or calculation based on one or more sensor inputs directly into the controller or using data transmitted to the controller from a source outside the direct controller area).

[0037] As used herein, a "controller" may refer to a hardware module or component including one or more processors or microcontrollers, memory, sensors, one or more actuators, communication interfaces, etc., any portion of which may be collectively referred to as a "circuit". As described herein, the corresponding functions and steps performed by a given controller, control circuit, etc. may be performed by multiple controllers, processors, etc. in common. For example, a processor, processing device, controller, control circuit, etc. "configured to perform" may refer to a single processor, processing device, controller, etc. configured to perform both A and B, or may refer to a first processor, processing device, controller, etc. configured to perform A and a second processor, processing device, controller, etc. configured to perform B. For simplicity, a "control circuit configured to perform A and B" may refer to a single or multiple processors, processing devices, controllers, etc. that are collectively configured to perform A and B. In some examples, one or more functions may be performed remotely (e.g., relative to a vehicle), such as at a controller, processor, circuit, etc. of a remote server, cloud computing system, and / or other remote processing system.

[0038] In some embodiments, the controller 100 may perform the methods described herein. However, the fact that the methods described herein are performed by the controller 100 is not meant to be limiting, and any type of software executed on a controller or processor may perform the methods described herein without departing from the scope of the present disclosure. For example, a controller (such as a processor executing software within a computing device) may perform the methods described herein.

[0039] Figure 2 An example EPS system 200 in accordance with the principles of the present disclosure is generally schematically illustrated. Although described with respect to an EPS system, the principles of the present disclosure may be implemented with other types of steering systems (such as SbW and ADAS systems) as well as non-steering systems.

[0040] EPS system 200 includes a steering system 204. For simplicity, details of steering system 204 are omitted. For example, steering system 204 can include a rack-and-pinion type steering mechanism that responds to operator input (e.g., a steering wheel, a steering wheel, etc.). In some examples, steering assistance can be provided via an electric machine such as motor 208 (e.g., a permanent magnet synchronous motor).

[0041] The motor 208 responds to a controller or control circuit 212, which receives power from a power source 216 (which may include a battery, an alternator, etc.) via a wiring harness 220 to control the motor 208. Although described herein as using a wiring harness 220, the principles of the present disclosure may be implemented for systems that include other types of paths between the power source 216 and the corresponding components as described above. Although shown as a single connection between the power source 216 and the controller 212 for simplicity, the wiring harness 220 may include multiple wired connections to various components of the EPS system 200, such as one or more direct connections to the motor 208. The wiring harness 220 may include one or more conductors, such as wire segments, bus bars, etc. In some examples, the wiring harness 220 includes one or more connectors, such as spade connectors, sockets, plugs, lugs, terminals, etc. In addition, although described with respect to a single controller 212, the EPS system 200 may include multiple controllers, each controller having different connections between the controller and the power source 216, respective motors, etc., and various health status indicators of the electrical connections of the corresponding controllers, motors, etc. may be obtained (e.g., calculated, measured, etc.) according to the principles of the present disclosure.

[0042] The controller 212 receives various measurement signals from various sensors, including but not limited to one or more sensors 224 configured to generate measurement signals associated with the steering system 204, and vehicle status information (vehicle speed, mileage, temperature, etc.) received through the vehicle communication bus. The measurement signals may include a steering angle (e.g., measured by a position sensor) and a motor speed. The motor speed represented as ω_m can be measured and / or calculated. For example, the motor speed ω_m can be calculated as a change in the motor position θ measured by the position sensor within a specified time interval. For example, the motor speed ω_m can be determined as a derivative of the motor position according to the equation ω_m=Δθ / Δt, where Δt is the sampling time and Δθ is the position change during the sampling interval. Alternatively, the motor speed can be derived from the motor position as the time rate of change of the position.

[0043] The controller 212 controls the motor 208 based on various inputs, measurement signals, etc. to provide torque assistance to the steering system 204. For example, the controller 212 is configured to supply a corresponding voltage to the motor 208 via an inverter (not shown) so that the motor 208 generates a desired torque and / or position, and the inverter may optionally be incorporated into the controller 212.

[0044] The wiring harness 220 has an associated resistance (e.g., harness resistance) that represents the resistance of electrical components in the current flow path between the power source 216 and the input of the controller 212 (including the path to and from the controller 212). For example, the harness resistance has a harness resistance value R 线束 , which is the sum of the resistances of the wiring harness 220, the vehicle ground, and one or more connectors or connections. Over time, these connections may corrode and / or degrade and cause the total path resistance between the power source 216 and the controller 212 to increase. Therefore, the degradation of the connection can be determined based on the harness resistance.

[0045] Figure 3 An example degradation of a performance factor P (e.g., for a limiting performance factor P(L)) over the life of an electrical connection t(L) is shown. After the formation period shown at 300, the performance is relatively stable (i.e., relatively flat) for period 304 before experiencing accelerated aging and performance degradation in period 308. Thus, while resistance may generally indicate degradation, resistance itself may not accurately indicate health, degradation, etc. Although shown as generally increasing over period 300, the performance factor P may vary (e.g., increase, decrease, etc.) over period 300. For example, period 300 may correspond to a "settling" period where various components, materials, connections, etc. stabilize after installation.

[0046] Figure 4 Example sample measurements or calculations (e.g., measurements or calculations of resistance) indicating intermittent degradation (at 400) and non-intermittent degradation (at 404) are shown. The sample measurement 404 indicating non-intermittent degradation generally increases over time (e.g., increases exponentially as shown). Thus, the sample measurement 404 reaches and exceeds an example threshold value (such as the critical resistance shown at 408). As used herein, the critical resistance 408 is selected as a resistance value that indicates that significant degradation of the electrical connection has occurred (e.g., degradation sufficient to cause performance degradation that can be noticed by the driver). In addition, when the critical resistance 408 is reached, the measured resistance can begin to increase at a greater rate, indicating accelerated aging and degradation.

[0047] In different examples, the critical resistance can be set based on different metrics, including but not limited to: based on when the resistance begins to increase exponentially; based on when the resistance reaches a calibrable predetermined resistance (e.g., 20 milliohms) that is known to cause significant performance degradation; based on when the resistance is a multiple (e.g., 1.5 times, 2 times, etc.) of the lowest known resistance value (i.e., historically), when significant degradation has occurred from a stable baseline condition; and, based on when the resistance is within a predetermined or variable range of a critical value that requires maintenance. In some examples, the critical resistance can be set to a value that is lower than (and earlier in time) the system performance will be affected. For example, the critical resistance can be determined based on the rate of increase of the resistance change and the fixed time maintained before exceeding the critical resistance to provide the user with sufficient maintenance opportunities before reaching the critical resistance. This lower value can be referred to as a warning resistance level or a notification resistance level, which is derived from the rate of increase of the resistance and the amount of time required for the appropriate maintenance to be scheduled and performed.

[0048] In contrast, sample measurements 400 indicating intermittent degradation do not generally increase over time, but only intermittently exceed critical resistance 408. For example, one or more conditions such as fretting or arcing may result in highly variable measurements. Thus, sample measurements 400 may not accurately indicate the actual resistance at any given time, and therefore the amount of degradation.

[0049] Figure 5A An example sample resistance measurement 500 is shown relative to a critical resistance 502. In this example, the measurements generally follow a "bathtub" curve corresponding to an initial decrease in resistance during a first "stable" period, a generally flat, stable second period, and a generally exponential increase in a third period. Intermittency detection systems and methods according to the present disclosure are configured to generate one or more adaptive control thresholds 504 and detect degradation intermittency based on the control thresholds 504.

[0050] For example, the control threshold 504 corresponds to the average of n previous measurement samples plus a calibrable offset (e.g., m) based on the sample measurement result 500. For example, the offset corresponds to the expected measurement change. In this example, n=6 and m=7, and the control threshold 504 is calculated for the sample measurement result 500. For example, the control threshold C corresponds to the average of n previous samples plus the offset m, as shown below: C=S / n+m, where S corresponds to the sum of the n previous samples.

[0051] A sample measurement corresponding to a more realistic signal (e.g., an example signal with noise) is shown at 506. In this example, variations in sample measurement 506 may be caused by vibration, electrical noise, measurement repeatability, quantization error, and / or other random factors, rather than by fretting, arcing, or other intermittent degradation conditions. Systems and methods according to the present disclosure are configured to compare sample measurement 506 with corresponding adaptive control thresholds to determine whether sample measurement 506 indicates the presence of fretting or other degradation intermittency. Adaptive limits based on real-world noise data will tend to be noisier than control thresholds 504 based on a clean (i.e., noise-free) input signal (as represented by measurement 500).

[0052] Figure 5B An example sample resistance measurement 510 of a noisy signal is shown relative to a critical resistance 512 and an adaptive control threshold 514. In this example, the adaptive control threshold 514 is generated based on the measurement 510 (e.g., based on an average of n previous samples of the measurement 510 plus an offset m). In this example, the noise of the signal does not produce any samples that are greater than the corresponding value of the control threshold 514. Therefore, degradation intermittency is not detected.

[0053] Figure 5C Example resistance measurements 518 corresponding to degradation intermittency, such as that caused by fretting, are shown relative to a critical resistance 520 . Figure 5D An example first adaptive control threshold 524 and a second adaptive control threshold 526 are shown. In this example, the adaptive control thresholds 524 and 526 are generated based on the resistance measurement 518. For example, the first (e.g., upper) control threshold 524 is generated based on the average of n previous samples of the measurement 518 plus an offset m. Conversely, the second (e.g., lower) control threshold 526 is generated based on the average of n previous samples of the measurement 518 minus the offset m. Thus, the control thresholds 524 and 526 define a threshold window 528. In other words, the control thresholds 524 and 526 define a maximum boundary or limit and a minimum boundary or limit of the threshold window 528, respectively.

[0054] Figure 5E Shown with Figure 5C Example resistance measurement results of 518 superimposed Figure 5DThe control thresholds 524 and 526 of FIG. 5A are measured. The systems and methods according to the present disclosure are configured to detect (e.g., diagnose) degradation intermittency, such as fretting wear, based on a comparison between the resistance measurement 518 and the control thresholds 524 and 526. For example, the resistance measurement 518 is compared to the control thresholds 524 and 526 to determine whether the resistance measurement 518 exceeds the control thresholds 524 and 526. As used herein, the term "exceeds" means that the resistance measurement 518 is greater than the control threshold 524 and less than the control threshold 526.

[0055] In response to determining that one or more of the resistance measurements 518 exceed the control thresholds 524 and 526 (i.e., exceed the threshold window 528), degradation intermittency can be detected and identified, and one or more actions can be performed. In one example, fretting wear can be diagnosed based on the frequency or number of times the resistance measurements 518 exceed the control thresholds 524 and 526 (e.g., over a predetermined diagnostic period or number of samples).

[0056] Fig. 5F An example frequency count 532 is shown corresponding to the number of times the resistance measurement 518 (e.g., during the lifetime of the corresponding electrical connection as described above) exceeds the control thresholds 524 and 526. In other words, the frequency count 532 corresponds to the number of times the resistance measurement 518 is greater than the control threshold 524, less than the control threshold 536, and outside of the range defined by both the first control threshold 524 and the second control threshold 526 (i.e., the threshold window 528).

[0057] For example, the first count 534 corresponds to the number of times the resistance measurement 518 is outside of the threshold window 528. The second count 536 corresponds to the number of times the resistance measurement 518 exceeds the control threshold 524. The third count 538 corresponds to the number of times the resistance measurement 518 exceeds the control threshold 526. Thus, the first count 534 may correspond to the sum of the second count 536 and the third count 538.

[0058] In this manner, the systems and methods of the present disclosure are configured to detect and selectively diagnose degradation intermittency, such as fretting, based on a frequency count 532 corresponding to the number of times the resistance measurement 518 is outside of an expected range of variation that is dynamically calculated and adjusted based on the historical behavior of the resistance measurement 518. For example, fretting can be diagnosed based on the first count 534, the second count 536, the third count 536, or a combination thereof.

[0059] In one example, to diagnose degradation intermittency, the first count 534 can be compared to a first count threshold, the second count 536 can be compared to a second count threshold, and the third count 538 can be compared to a third count threshold. The first count threshold can be greater than each of the second count threshold and the third count threshold, but less than the sum of the second count threshold and the third count threshold.

[0060] The second count threshold and the third count threshold may be the same or different. For example, certain intermittencies may be more likely to cause the measurement result 518 to exceed the control threshold 526 than the control threshold 524, or vice versa. Therefore, one of the second count threshold and the third count threshold may be greater than or less than the other of the second count threshold and the third count threshold to increase sensitivity to a particular type of degradation intermittency and facilitate detection of a particular type of degradation intermittency. In some examples, the type of degradation intermittency can be identified based on which of the first threshold and the second threshold is exceeded. For example, a first type of degradation intermittency can be diagnosed in response to the second count 536 exceeding the second count threshold, while a second type of degradation intermittency can be diagnosed in response to the third count 538 exceeding the third count threshold.

[0061] While determining intermittency may be simply based on exceeding a count value corresponding to one of the control thresholds, determining intermittency may be performed using other methods. For example, it may be desirable to detect intermittency in response to any instance below a control threshold or in response to at least two instances above an upper control threshold and one instance below a lower control threshold. As another example, intermittency may be determined in response to a first count above a first control threshold and a second count below a second threshold occurring within a predetermined number of measurements, which may represent a relatively rapidly changing value indicative of intermittency (i.e., a rate of change detection outside of an expected rate of change range).

[0062] In other examples, one or more of the counts 532 may be selectively reset, reduced, or otherwise adjusted. For example, the counts 532 may correspond to only a predetermined subset of the measurements 518, such as the most recent p measurements 518 (where p may be a calibratable value that is different for each of the counts 532), only measurements 518 from a predetermined period (e.g., last month, previous two months, etc.), and the like. In another example, in response to determining that the measurement 518 has not exceeded any of the control thresholds 524 and 526 within a predetermined reset period or number of samples (e.g., the measurement 518 has not exceeded any of the control thresholds 524 and 526 within the last three months, within the last twenty samples, etc.), one or more of the counts 532 may be reset (e.g., set to 0) or reduced. One or more of the counts 532 may also be reset after maintenance or replacement of various components.

[0063] Figure 6 6 is a flow chart generally illustrating the steps of an example method 600 for detecting degradation intermittency according to the principles of the present disclosure. The method 600 may be performed by one or more components of the systems described herein, such as one or more controllers (e.g., controller 100), one or more processors or processing devices (e.g., processor 102), and / or other circuits. In an example, one or more processors are configured to execute instructions stored in a memory to perform the method 600.

[0064] At 604, one or more measurements indicative of the SOH of the electrical connection are generated and received. The measurements may include, but are not limited to, one or more resistances associated with the electrical connection as described herein. In one example, electrical power is applied as a sinusoidal current to a motor associated with an EPS system, a response corresponding to the applied power is measured, and the resistance of the electrical connection is calculated based on the current and the response.

[0065] At 608, based on the measurements, one or more adaptive control thresholds are calculated. In one example, as described herein, an upper control threshold and a lower control threshold are calculated based on an average of a subset of the measurements and an offset that is added to and subtracted from the average, respectively. The upper control threshold and the lower control threshold define an adaptive threshold window.

[0066] At 612, a measurement (e.g., a current or most recent measurement) is compared to an upper control threshold and a lower control threshold. At 616, one or more frequency counts are updated in response to the comparison between the measurement and the upper control threshold and the lower control threshold. At 620, one or more frequency counts are compared to corresponding count thresholds.

[0067] At 624, in response to one or more of the frequency counts exceeding a corresponding count threshold, one or more actions are performed. In one example, one or more flags or other indicators are stored, generated, etc. For example, a notification or other indicator can be provided to a driver or user, a manufacturer, a dealer, a maintenance facility, etc. As an example, a notification is provided to a driver or user via an in-vehicle display or interface (e.g., a display of an infotainment system or other dashboard indicator), a mobile device, etc. For example, a notification (e.g., a check engine light or other indicator) can indicate that the vehicle requires maintenance, recommending that the driver or user schedule maintenance to check and replace or repair components of an electrical connection, an electrical power system, etc.

[0068] In another example, the notification may indicate that one or more predicted values ​​of the SOH of the electrical connection (e.g., cumulative health calculations, remaining usable life calculations, etc.) are inaccurate due to degradation intermittency. In examples where various SOH values ​​or indicators are provided to a driver or other entity, such values ​​or indicators may not be given (e.g., not provided to the driver) in response to one or more of the frequency counts exceeding corresponding count thresholds. In some examples, since it may be difficult to accurately determine the SOH (and predict future SOH) when various intermittencies are present, the SOH may be set to 0 or another relatively low value to indicate that the current and / or future SOH is in an unpredictable state and the system health cannot be reliably predicted. The corresponding data may be sent to a remote server or cloud computing system for remote analysis, to a local diagnostic tool attached to a vehicle (e.g., an OBDII reader or other diagnostic device), etc.

[0069] In another example, control of one or more vehicle operating parameters (e.g., current provided to a motor, controller, etc.) may be adjusted under various conditions (e.g., when a measured temperature of the vehicle or a vehicle system is above a threshold). For example, in response to detecting degradation intermittency, various parameters (e.g., current provided to the motor) may be controlled to minimize additional wear on the electrical system and avoid failure.

[0070] The above discussion is intended to illustrate the principles and various embodiments of the present invention. Once the above disclosure is fully understood, many changes and modifications will become apparent to those skilled in the art. The appended claims are intended to be interpreted as covering all such changes and modifications.

[0071] The word "example" is used herein to mean used as an example, instance or illustration. Any aspect or design described as an "example" herein is not necessarily to be interpreted as being preferred or advantageous over other aspects or designs. On the contrary, the use of the word "example" is intended to present the concept in a specific way. As used in this application, the term "or" is intended to represent an inclusive "or" rather than an exclusive "or". That is, unless otherwise specified or clear from the context, "X includes A or B" is intended to represent any one of the natural inclusive arrangements. That is, if X includes A; X includes B; or X includes both A and B, "X includes A or B" is satisfied under any of the aforementioned examples. In addition, the articles "one" and "a" as used in this application and the appended claims should generally be interpreted as meaning "one or more", unless otherwise specified or clear from the context to refer to the singular form. In addition, the use of the term "a specific implementation" or "a specific embodiment" throughout the text is not intended to represent the same embodiment or specific implementation, unless so described.

[0072] The specific implementation of the systems, algorithms, methods, instructions, etc. described herein may be implemented in hardware, software, or any combination thereof. The hardware may include, for example, a computer, an intellectual property (IP) core, an application specific integrated circuit (ASIC), a programmable logic array, an optical processor, a programmable logic controller, microcode, a microcontroller, a server, a microprocessor, a digital signal processor, or any other suitable circuit. In the claims, the term "processor" should be understood to include any of the foregoing hardware, either alone or in combination. The terms "signal" and "data" are used interchangeably.

[0073] As used herein, the term module may include: a packaged functional hardware unit designed for use with other components; a set of instructions executable by a controller (e.g., a processor executing software or firmware); a processing circuit configured to perform a specific function; and an independent hardware or software component that interfaces with a larger system. For example, a module may include an application specific integrated circuit (ASIC); a field programmable gate array (FPGA); an electrical circuit; a digital logic circuit; an analog circuit; a combination of discrete circuits; a gate; and other types of hardware; or a combination thereof. In other embodiments, a module may include a memory that stores instructions that are executable by a controller to implement the features of the module.

[0074] Furthermore, in one aspect, for example, a general purpose computer or general purpose processor with a computer program can be used to implement the system described herein, which when executed implements any of the corresponding methods, algorithms and / or instructions described herein. Additionally or alternatively, for example, a special purpose computer / processor can be utilized, which may include other hardware for implementing any of the methods, algorithms or instructions described herein.

[0075] In addition, all or part of the specific implementation of the present disclosure may take the form of a computer program product accessible from, for example, a computer usable medium or a computer readable medium. A computer usable medium or a computer readable medium may be any device capable of, for example, tangibly containing, storing, transmitting or transporting a program for use by or in conjunction with any processor. The medium may be, for example, an electronic, magnetic, optical, electromagnetic or semiconductor device. Other suitable media are also available.

[0076] The above embodiments, specific implementations and aspects have been described to allow easy understanding of the present invention and do not limit the present invention. On the contrary, the present invention is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, and its scope should be given the broadest interpretation to cover all such modifications and equivalent structures permitted under the law.

Claims

1. A method for detecting degraded intermittency in an electrical connection in a steering system of a vehicle, the method comprising using a processor configured to execute instructions: receiving an input indicative of a resistance associated with the electrical connection, wherein the input is indicative of a plurality of measurements of the resistance; calculating at least one adaptive control threshold based on the received input; comparing a first measurement of the plurality of measurements to the at least one adaptive control threshold; determining whether the electrical connection has degraded intermittent properties in response to a comparison between the first measurement and the at least one adaptive control threshold; as well as In response to determining that the electrical connection has the degraded intermittent nature, at least one action is performed.

2. The method according to claim 1, wherein: Calculating the at least one adaptive control threshold includes calculating a first adaptive control threshold and a second adaptive control threshold, the first adaptive control threshold and the second adaptive control threshold defining a threshold window.

3. The method according to claim 2, wherein: Comparing the first measurement result includes comparing the first measurement result with the first adaptive control threshold and the second adaptive control threshold.

4. The method according to claim 3, further comprising: In response to the first measurement result being greater than the first adaptive control threshold or less than the second adaptive control threshold, it is determined that the electrical connection has the degradation intermittent nature.

5. The method according to claim 4, further comprising: The number of times that one of the plurality of measurement results is greater than the first adaptive control threshold or less than the second adaptive control threshold is counted, and the electrical connection is determined to have the degradation intermittent property based on the counted number of times.

6. The method according to claim 5, further comprising: In response to a comparison between the counted number of times and at least one count threshold, it is determined that the electrical connection has the degradation intermittent nature.

7. The method according to claim 1, further comprising: The at least one adaptive control threshold is calculated based on (i) an average value of a predetermined number of the plurality of measurements and (ii) an offset.

8. The method according to claim 1, further comprising: The resistance is obtained by supplying a sinusoidal current to a motor of the steering system, measuring a response of the motor and calculating the resistance based on the sinusoidal current and the measured response.

9. The method according to claim 8, wherein: The sinusoidal current is a current that does not generate torque.

10. The method according to claim 1, wherein: The steering system is an electric power steering system, and the electrical connection is an electrical connection between a motor of the electric power steering system and a power source.

11. The method according to claim 1, wherein: Performing the at least one action includes at least one of the following: In response to determining that the electrical connection has the degraded intermittent nature, generating and displaying an indicator; and In response to determining that the electrical connection has the degraded intermittent nature, at least one operating parameter of the vehicle is controlled.

12. A system for detecting degraded intermittency in an electrical connection in a steering system of a vehicle, the system comprising: at least one sensor configured to generate an output indicative of a resistance associated with the electrical connection, wherein the input is indicative of a plurality of measurements of the resistance; and The controller is configured as: calculating at least one adaptive control threshold based on the received input; comparing a first measurement of the plurality of measurements to the at least one adaptive control threshold; determining whether the electrical connection has degraded intermittent properties in response to a comparison between the first measurement and the at least one adaptive control threshold; and In response to determining that the electrical connection has the degraded intermittent nature, at least one action is performed.

13. The system according to claim 12, wherein: Calculating the at least one adaptive control threshold includes calculating a first adaptive control threshold and a second adaptive control threshold, the first adaptive control threshold and the second adaptive control threshold defining a threshold window.

14. The system according to claim 13, wherein: Comparing the first measurement result includes comparing the first measurement result with the first adaptive control threshold and the second adaptive control threshold.

15. The system of claim 14, wherein: The controller is further configured to determine that the electrical connection has the degradation intermittent nature in response to the first measurement result being greater than the first adaptive control threshold or less than the second adaptive control threshold.

16. The system of claim 15, wherein: The controller is further configured to count the number of times a measurement result among the plurality of measurement results is greater than the first adaptive control threshold or less than the second adaptive control threshold, and determine that the electrical connection has the degradation intermittent nature based on the counted number of times.

17. The system of claim 16, wherein: The controller is further configured to determine that the electrical connection has the degraded intermittent nature in response to a comparison between the counted number of times and at least one count threshold.

18. The system of claim 12, wherein: The controller is further configured to calculate the at least one adaptive control threshold based on (i) an average value of a predetermined number of the plurality of measurements and (ii) an offset.

19. The system of claim 12, wherein: The controller is further configured to obtain the resistance by supplying a sinusoidal current to a motor of the steering system, measuring a response of the motor, and calculating the resistance based on the sinusoidal current and the measured response.

20. The system of claim 12, wherein: The steering system is an electric power steering system, and the electrical connection is an electrical connection between a motor of the electric power steering system and a power source.

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