INTERMITTENT DETECTOR FOR RESISTANCE IN DRIVE GRAGUES

Abstract

A method for detecting deterioration intervals in an electrical connection in a vehicle steering system comprises, using a processor configured to execute instructions, receiving an input specifying a plurality of resistance measurements associated with the electrical connection, calculating at least one adaptive control threshold based on the received input, comparing a first measurement of the plurality of measurements with the at least one adaptive control threshold, determining whether the electrical connection exhibits deterioration intervals in response to the comparison between the first measurement and the at least one adaptive control threshold, and performing at least one action in response to the determination that the electrical connection exhibits deterioration intervals.

Description

CROSS REFERENCE TO RELATED APPLICATIONSThis application claims the benefit of U.S. Provisional Application No. 63 / 542,437, filed October 4, 2023. The entire disclosure of the above application is incorporated herein by reference.TECHNICAL FIELDThis disclosure relates to systems and methods for monitoring the health of connections between a power source and an electric power steering (EPS) system.BACKGROUND OF THE INVENTIONA vehicle, such as a car, truck, sport utility vehicle, crossover, mini-van, watercraft, aircraft, sport utility vehicle, recreational vehicle, or other suitable means of transportation, typically includes a steering system, such as an electronic power steering (EPS) system, steer-by-wire (SbW) steering system, hydraulic steering system, or other suitable steering system. The steering system of such a vehicle typically controls various aspects of vehicle steering, including providing a steering assist to the driver of the vehicle, controlling steerable wheels of the vehicle, and the like.SUMMARY OF THE INVENTIONThis disclosure relates generally to determining the state of health of an electrical connection in a steering system of a vehicle.In one example, a method for detecting degradation interferences in an electrical connection in a steering system of a vehicle, using a processor configured to execute instructions, comprises receiving an input indicative of a plurality of resistance measurements associated with the electrical connection, 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 degradation interference in response to the 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 the degradation interference.Other aspects of the disclosed embodiments include systems configured to perform steps and functions of the described methods.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 DRAWINGSThe disclosure will be best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that the various features of the drawings are not to scale according to common practice. On the contrary, the dimensions of the various features are arbitrarily expanded or reduced for clarity. FIG. 1A generally illustrates a vehicle according to the principles of the present disclosure. FIG. 1B generally illustrates a controller according to the principles of the present disclosure. FIG. 2 schematically illustrates, generally, an example electronic power steering (EPS) system according to the principles of the present disclosure. FIG. 3 generally illustrates example degradation of an electrical connection over a lifetime. FIG. 4 generally illustrates example sample measurements or calculations indicative of intermittent and non-intermittent degradation. FIGS. 5A-5F generally illustrate example sample measurements relative to various control thresholds in accordance with the principles of the present disclosure. FIG. 6 is a flow chart generally illustrating steps of an example method for detecting degradation interferences in accordance with the principles of the present disclosure.DETAILED DESCRIPTIONThe following discussion relates to various embodiments of the disclosure. Although one or more of these embodiments may be preferred, the disclosed embodiments should not be interpreted or otherwise used as limiting the scope of the disclosure, including the claims. Moreover, one skilled in the art will understand that the following description has a broad scope of application and the discussion of an embodiment is intended to be exemplary of this embodiment only and does not mean that the scope of the disclosure, including the claims, is limited to this embodiment.As described, a vehicle such as a car, truck, sport utility vehicle, crossover, mini-van, watercraft, aircraft, sport utility vehicle, recreational vehicle, or other suitable means of transport typically includes a steering system such as an electronic power steering (EPS) system, steer-by-wire (SbW) steering system, hydraulic steering system, or other suitable steering system. The steering system of such a vehicle typically controls various aspects of vehicle steering, including providing a steering assist to the driver of the vehicle, controlling steerable wheels of the vehicle, and the like. Although the principles of the present disclosure are described herein with respect to vehicles, they may also be implemented in other types of transportation or non-transportation devices, including steering systems.The vehicle typically includes one or more electric machines, such as electric motors, configured to control various aspects of a steering system of the vehicle. A path for providing power from the vehicle power source (e.g., battery, alternator, power supply) to one or more motors of the steering system may be provided. This path may include one or more wiring harnesses, wires, connectors, terminals, fuses, or other (e.g., non-conventional) paths for conducting current, such as chassis ground, bus bar, through an engine block, etc. All that may provide a low enough impedance path (high power connection) for power transfer may be used to power the or from the engine controller. A high-power electrical harness and connector may supply electrical power from an electrical system of a vehicle (e.g., battery and / or alternator) to a motor controller for one or more motors of the steering system. Over the life of the vehicle, the characteristics of the high power connection may deteriorate, ultimately resulting in insufficient input power being provided to provide the desired electromechanical output power for providing the steering assist or steering angle function. This degradation is recognizable as an actual increase in the resistance of the power connector or harness. In attempting to supply this electromechanical output power, the current draw through the increased resistance of the high power connection or harness causes a large voltage drop between the vehicle supply and the motor controller, which may result in the total voltage at the input of the motor controller being low enough to cause a "shutdown" or "drop of operating state", which in turn may result in a loss of function, such as loss of support 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 engine controller input is not shut down, reduced available power may result in lower torque assist, delayed response, poor feedback, reduced angle control, and overall reduced steering power.In some embodiments, it is desirable to detect this degraded state and / or limit an electromechanical output power command based on detecting this degraded state to reduce the required input power and prevent loss of function of the steering system, such as loss of assist in an EPS system or loss of angle control in an ADAS or SbW system. Although performance may be reduced, alternatives may be preferred that may include a complete loss of assist or angle control function.Some systems may implement techniques for determining degradation of the input power connection (or the wire harness) using available signals within the existing control module and software. An example system for determining degradation of the power connection is described in more detail in U.S. patent application Ser. No. 17 / 733,434, filed Apr. 29, 2022, the entire disclosure of which is incorporated herein by reference. In this example, electrical power is supplied to the motor phases and the response is measured. The applied power is V*I, where V and I are vector magnitudes of the applied motor voltage and motor current, respectively. In some examples, the applied electric power is selected to generate a zero motor torque. For example, in EPS systems, sinusoidal, non-torque producing current is applied to the motor phases. For ADAS and SbW systems, 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 bridge voltage of the inverter or at an input of a control module) is an indication of degradation and the state of health (SOH) of the input power connection.In some examples, the detectable degradation generally increases with time (e.g., exponential, linear, etc.). For example, measurement of a representative resistance (e.g., a resistance associated with the power connector or harness as described above) may generally increase with increasing degradation over time. However, in some examples, features or behaviors corresponding to degradation occur intermittently. For example, one or more measurements indicative of degradation may not generally increase over time, but may be randomlyhaving with intermittent increasing and decreasing measurements (e.g., due to fretting corrosion, arcing, etc.). Accordingly, a first resistance measurement may indicate that degradation has occurred slightly above a threshold (e.g., a critical resistance), while a subsequent second resistance measurement indicates that the degradation is below the threshold.Accordingly, systems and methods for detecting interference according to the present disclosure are configured to accurately detect degradation interferences, as described in more detail below.Additionally, although the principles of the present disclosure are described with respect to steering systems, they may be implemented in other types of vehicle or non-vehicle systems that include a motor and an actuator (e.g., a windshield wiper system, a propulsion system, a window controller, etc.).FIG. 1A generally illustrates a vehicle 10 according to the principles of the present disclosure. The vehicle 10 may include any suitable vehicle, such as a car, truck, sport utility vehicle, mini-van, crossover, any other passenger vehicle, any suitable utility vehicle, or any other suitable vehicle. While the vehicle 10 is illustrated as a wheeled passenger vehicle and for use on roads, the principles of the present disclosure may be applied to other vehicles, such as aircraft, boats, trains, drones, or other suitable vehicles.The vehicle 10 includes a vehicle body 12 and a hood 14. A passenger compartment 18 is at least partially bounded 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 the hood 14 provides access to the engine compartment 20 when the hood 14 is in a first or open position and the hood 14 covers the engine compartment 20 when the hood 14 is in a second or closed position. In some embodiments, the engine room 20 may be disposed at a portion of the vehicle 10 that is located further rearward than illustrated.The passenger compartment 18 may be disposed behind the engine compartment 20, but may also be disposed in front of the engine compartment 20 in embodiments where the engine compartment 20 is disposed in the rear portion of the vehicle 10. The vehicle 10 may include any suitable propulsion system including an internal combustion engine, one or more electric motors (e.g., an electric vehicle), one or more fuel cells, a hybrid propulsion system (e.g., a hybrid vehicle) including a combination of an internal combustion engine, one or more electric motors, and / or another suitable propulsion system.In some embodiments, the vehicle 10 may include a gasoline engine, such as a gasoline engine. In some embodiments, the vehicle 10 may include a diesel engine, such as a compression ignition engine. The engine compartment 20 houses and / or encloses at least some components of the propulsion system of the vehicle 10. additionally or alternatively, propulsion controls such as an accelerator actuator (e.g., an accelerator pedal), a brake actuator (e.g., a brake pedal), a hand wheel, and other such components are disposed within the passenger compartment 18 of the vehicle 10. The propulsion operators may be actuated or controlled by an operator of the vehicle 10 and may be directly connected to corresponding components of the propulsion system, such as a throttle, a brake, a vehicle axle, a vehicle transmission, and the like. In some embodiments, the propulsion operators may communicate signals to a vehicle computer (e.g., drive by wire), which in turn may control the corresponding propulsion component of the propulsion system. Thus, in some embodiments, the vehicle 10 may be an autonomous vehicle.In some embodiments, the vehicle 10 includes a transmission connected to a crankshaft via a flywheel or clutch or fluid clutch. In some embodiments, the transmission includes a manual transmission. In some embodiments, the transmission includes an automatic transmission. The vehicle 10, in the case of an internal combustion engine or hybrid vehicle, may include one or more pistons that cooperate with the crankshaft to generate a force that is transmitted via the transmission to one or more axles that rotate the wheels 22. When the vehicle 10 includes one or more electric motors, a vehicle battery and / or fuel cell provides power to the electric motors to rotate the wheels 22.The vehicle 10 may include automatic vehicle propulsion systems, such as a cruise controller, an adaptive cruise controller, an automatic brake controller, other automatic vehicle propulsion systems, or a combination thereof. The vehicle 10 may be an autonomous or semi-autonomous vehicle or another suitable type of vehicle. The vehicle 10 may include additional or fewer features than those generally illustrated and / or disclosed herein.In some embodiments, the vehicle 10 may include an Ethernet component 24, a controller area network (CAN) bus 26, a media oriented system transport (MOST) component 28, a FlexRay component 30 (e.g., a brake-by-wire system, and the like), and a local interconnect network (LIN) component 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, for example, sensors inside or outside the vehicle to, for example, various processors or controllers inside or outside the vehicle. The vehicle 10 may include additional or fewer features than those generally illustrated and / or disclosed herein.In some embodiments, although not shown, the vehicle 10 may include a steering system, such as an EPS system, a steering-by-wire steering system (e.g., which may include or communicate with one or more controllers that control components of the steering system without the use of a mechanical connection between the hand 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 another suitable steering system.The steering system may include a control system or mechanism, a control system or mechanism, or a combination thereof. The steering system may be configured to receive various inputs including, but not limited to, a hand wheel position, an input torque, one or more wheel positions, vehicle speed, temperature, other suitable inputs or information such as any available signals on a vehicle communication bus, or a combination thereof.Additionally or alternatively, the inputs may include a hand wheel torque, a hand wheel angle, a motor speed, a vehicle speed, an estimated motor torque command, another suitable input, or a combination thereof. The steering system may be configured to provide a steering function and / or control for the vehicle 10. For example, the steering system may generate an assist torque based on the various inputs. The steering system may be configured to selectively control a motor of the steering system using the assist torque to provide steering assist to the driver of the vehicle 10. The steering system of the present disclosure is configured to implement inter-mean detection systems and methods as described in more detail below.In some embodiments, the vehicle 10 may include a controller, such as the controller 100, as generally illustrated in FIG. 1B. 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, for example, the various functions of the steering system and / or various functions of the vehicle 10. The controller 100 may include a processor 102 and a memory 104. Processor 102 may include any suitable processor, such as those described herein. Additionally or alternatively, the controller 100 may include any number of processors, in addition to or different from the processor 102. The memory 104 may comprise a single disk or a plurality of disks (e.g., hard disks) and includes a memory management module that manages one or more partitions within the memory 104. In some embodiments, the memory 104 may include flash memory, solid state memory (semiconductor memory), or the like. The memory 104 may include random access memory (RAM), 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.The controller 100 may receive one or more signals from various measurement devices or sensors 106 indicative of sensed or measured characteristics of the vehicle 10. The sensors 106 may include any suitable sensors, measurement devices, and / or other suitable mechanisms. The sensors 106 may include, for example, one or more torque sensors or devices, one or more hand wheel position sensor or devices, one or more motor position sensor or devices, one or more position sensors or devices, one or more position sensors or devices, other suitable sensors or devices, or a combination thereof. The one or more signals may indicate a hand wheel torque, a hand wheel angle, a motor speed, a vehicle speed, other suitable information, or a combination thereof. As used herein, "sensors" may correspond to physical sensors or derived signals (e.g., signals derived from algorithms or calculations based on one or more sensor inputs, both of which are either directly input to the controller or which use data conveyed to the controller from sources outside of the immediate controller area).As used herein, the term "controller" may refer to a hardware module or assembly that includes one or more processors or microcontrollers, memories, sensors, one or more actuators, a communication interface, etc., all portions of which may be collectively referred to as "circuits.". As described herein, the respective functions and steps performed by a given controller, control circuitry, etc. may be performed jointly by multiple controllers, processors, etc. For example, a processor, processing device, controller, control circuitry, 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 one(s) single(s) 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 the vehicle), such as at a controller, processor, circuitry, etc., a remote server, cloud computing system, and / or other remote processing system.In some embodiments, the controller 100 may perform the methods described herein. However, the methods described herein as performed by the controller 100 are not to be considered limiting, and any type of software executing on a controller or processor may perform the methods described herein without departing from the scope of this disclosure. For example, a controller, such as a processor, executing software within a computing device may perform the methods described herein.FIG. 2 schematically illustrates, generally, an example EPS system 200 in accordance with the principles of the present disclosure. Although the principles of the present disclosure are described with respect to an EPS system, they may be implemented with other types of steering systems, such as SbW and ADAS systems, as well as non-steering systems.The EPS system 200 includes a steering system 204. Details of the steering system 204 are omitted for simplicity. For example, the steering system 204 may include a rack and pinion type steering mechanism that responds to an input from the operator (e.g., a steering wheel, a hand wheel, etc.). In some examples, the steering assist may be provided via an electric machine, such as a motor 208 (e.g., a permanent magnet synchronous motor).The motor 208 is responsive to a controller or control circuit 212 that receives power for controlling the motor 208 via a wiring harness 220 from a power supply 216 (which may include a battery, a generator, etc.). Although the use of the wiring harness 220 is described herein, the principles of the present disclosure may be implemented for systems that include other types of paths between the power supply 216 and the respective components, as described above. Although shown for simplicity as a single connection between the power supply 216 and the controller 212, 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 pieces, bus bars, etc. In some examples, the wiring harness 220 includes one or more connectors, such as tabs, sockets, plugs, ears, cable terminals, etc. Further, although the EPS system 200 is described with respect to a single controller 212, it may include a plurality of controllers each having different connections between the controller and the power supply 216, a respective motor, etc., and various function indicators may be obtained (e.g., calculated, measured, etc.) according to the principles of the present disclosure for electrical connections of the respective controllers, motors, etc.The controller 212 receives various measurement signals from respective sensors including, but not limited to, one or more sensors 224 configured to generate measurement signals associated with the steering system 204 along with vehicle state information (vehicle speed, mileage, temperature, etc.) received via a vehicle communication bus. The measurement signals may include a steering angle (e.g., measured by a position sensor) and a motor speed. A motor speed, referred to as ω_m, may be measured, calculated, or a combination thereof. For example, the motor speed ω_m may be calculated as a change in a motor position θ as measured by a position sensor over a prescribed time interval. For example, the motor speed ω_m may be determined as a derivative of the motor position θ from the equation ω_m= Δ / Δt, where Δt is a sampling time and Δθ is a position change during the sampling interval. Alternatively, the motor speed may be derived from the motor position as a time rate of change of position.The controller 212 controls the motor 208 to provide torque assist to the steering system 204 based on various inputs, measurement signals, etc. For example, the controller 212 is configured to supply corresponding voltages to the motor 208 via an inverter (not shown), which may optionally be integrated with the controller 212 to cause the motor 208 to generate a desired torque and / or position.The harness 220 has an associated resistor (e.g., a harness resistor) that represents the resistance of electrical components in a current flow path between the power supply 216 and an input to the controller 212 (including paths to and from the controller 212). For example, the harness resistor has a harness resistance value R harness which is a sum of the resistances of the harness 220, the vehicle ground, and one or more connectors or interconnects. Over time, these connections may erode and / or degrade, leading to an increase in the overall path resistance between the power supply 216 and the controller 212. Accordingly, the deterioration of the connections can be determined based on the harness resistance.FIG. 3 illustrates example degradation of a performance factor P (e.g., for a limit performance factor P(L)) over an electrical connection lifetime t(L). Following a formation period shown at 300, the performance is relatively stable (i.e., relatively flat) for a period 304 before accelerated aging and performance degradation occurs in a period 308. Accordingly, while the resistance may generally indicate degradation, the resistance alone may not be an accurate indicator of the operating state, degradation, etc. Although the performance factor P is generally shown as increasing within the period 300, it may vary (e.g., increase, decrease, etc.) within the period 300. For example, the period 300 may correspond to a "habituation period" during which various components, materials, joints, etc., stabilize after installation.FIG. 4 illustrates example sample measurements or calculations (e.g., measurements or calculations of resistance) indicative of intermittent degradation (at 400) and non-intermittent degradation (at 404). The sample measurements 404 indicative of non-intermittent degradation generally increase with time (e.g., exponentially as shown). Accordingly, the sample measurements 404 reach and exceed an example threshold, such as a critical resistance shown at 408. As used herein, the critical resistor 408 is selected to indicate a resistance at which significant electrical connection degradation has occurred (e.g., sufficient degradation to cause performance degradation perceptible to the driver). Further, upon reaching the critical resistance 408, the measured resistance may begin to increase faster, indicating accelerated aging and degradation.In various examples, the critical resistance may be set based on different scales, including, but not limited to: based on when the resistance begins to exponentially increase; based on when the resistance reaches a calibrateable predetermined resistance (e.g., 20 milliohms) 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 ever known resistance (i.e., over the course) at which significant degradation occurred from a stable initial state; and based on when the resistance is within a predetermined or variable range of a critical value at which maintenance would be required. In some examples, the critical resistance may be set lower (and earlier in time) than a value at which system performance would be degraded. For example, the critical resistance may be determined based on an increasing rate of change of the resistance and a fixed maintenance time before exceeding the critical resistance to give the user sufficient opportunity to maintain before reaching the critical resistance. This lower value may be referred to as a warning or notification resistance level and is derived from the rate at which the resistance increases as well as the time required until appropriate maintenance can be scheduled and performed.In contrast, rather than generally increasing over time, the sample measurements 400 indicative of intermittent degradation exceed the critical resistance 408 only temporarily. For example, one or more conditions such as fretting corrosion or arcing can result in widely varying measurement results. Accordingly, the sample measurements 400 at a given time may not accurately indicate the actual resistance and, accordingly, the amount of degradation.FIG. 5A illustrates example sample resistance measurements 500 relative to a critical resistance 502. In this example, the measurements generally follow a "bathtub" curve corresponding to an initial resistance drop during a first "habituation" period, a generally flat, stable second period, and a generally exponential increase in a third period. Systems and methods for detecting interference according to the present disclosure are configured to generate one or more adaptive control thresholds 504, and detect degradation interferences based on the control threshold 504.For example, the control threshold 504 corresponds to an average of n previous measurement samples plus a calibrateable offset (e.g., m) based on the sample measurements 500. For example, the offset corresponds to an expected measurement deviation amount. In this example, n=6 and m=7 and the control threshold 504 is calculated for the sample measurements 500. For example, a control threshold C corresponds to an average of n previous samples plus the offset m as follows: C=S / n+m, where S corresponds to the sum of the n previous samples.At 506, sample measurements corresponding to a more realistic signal (e.g., an example signal with noise) are displayed. In this example, the deviations in the sample measurements 506 may be caused by vibration, electrical noise, measurement repeatability, quantization errors, and / or other random factors rather than by fretting corrosion, arcing, or other intermittent degradation conditions. Systems and methods according to the present disclosure are configured to compare the sample measurements 506 to a corresponding adaptive control threshold to determine whether the sample measurements 506 indicate the presence of fretting corrosion or other degradation indivisence. Adaptive thresholds based on real, noisy data tend to have more noise than control threshold 504, which is based on a clean (i.e., noise-free) input signal (as represented by measurements 500).FIG. 5B illustrates example resistance measurements 510 of a noisy signal 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 measurements 510 (e.g., based on an average of n previous samples of the measurements 510 plus an offset m). In this example, the noise of the signal does not result in samples that are greater than a corresponding value of the control threshold 514. Accordingly, deterioration abnormality is not detected.FIG. 5C illustrates example resistance measurements 518 corresponding to degradation inductance, such as frictional corrosion caused interference, relative to a critical resistance 520. FIG. 5D illustrates example first and second adaptive control thresholds 524 and 526. In this example, the adaptive control thresholds 524 and 526 are generated based on the resistance measurements 518. For example, the first (e.g., upper) control threshold 524 is generated based on an average of n previous samples of the measurements 518 plus an offset m. Conversely, the second (e.g., lower) control threshold 526 is generated based on the average of the n previous samples of the measurements 518 minus the offset m. Accordingly, the control thresholds 524 and 526 define a threshold window 528. In other words, the control thresholds 524 and 526 define maximum and minimum limits or boundaries of the threshold window 528, respectively.FIG. 5E illustrates the control thresholds 524 and 526 of FIG. 5D overlaid with the example resistance measurements 518 of FIG. 5C. Systems and methods according to the present disclosure are configured to detect (e.g., diagnose) degradation interferences, such as fretting corrosion, based on a comparison between the resistance measurements 518 and the control thresholds 524 and 526. For example, the resistance measurements 518 are compared to the control thresholds 524 and 526 to determine whether the resistance measurements 518 exceed the control thresholds 524 and 526. As used herein, the term "exceed" refers to the resistance measurements 518 being greater than the control threshold 524 and less than the control threshold 526.The degradation interferences may be detected and identified, and one or more actions may be performed in response to a determination that one or more of the resistance measurements 518 exceed the control thresholds 524 and 526 (i.e., exceed the threshold window 528). In one example, fretting corrosion may be diagnosed based on the frequency or number of times that the resistance measurements 518 exceed the control thresholds 524 and 526 (e.g., over a predetermined diagnostic period or number of samples).FIG. 5F illustrates example frequency counts 532 corresponding to a number of times that the resistance measurements 518 have exceeded the control thresholds 524 and 526 (e.g., over a lifetime of a corresponding electrical connection, as described above). In other words, the frequency counts 532 correspond to the number of times the resistance measurements 518 were greater than the control threshold 524, less than the control threshold 536, and outside a range defined by both the first and second control thresholds 524 and 526 (i.e., threshold window 528).For example, a first count 534 corresponds to the times at which the resistance measurements 518 were outside the threshold window 528. A second count 536 corresponds to the number of times the resistance measurements 518 have exceeded the control threshold 524. A third count 538 corresponds to a number of times the resistance measurements 518 have exceeded the control threshold 526. Accordingly, the first count 534 may correspond to a sum of the second count 536 and the third count 538.In this way, the systems and methods of the present disclosure are configured to detect and selectively diagnose deterioration interferences (such as fretting corrosion) based on the frequency counts 532 corresponding to a number of times the resistance measurements 518 were outside an expected range of deviation that is dynamically calculated and adjusted based on the history of the resistance measurements 518. For example, fretting corrosion may be diagnosed based on the first count 534, the second count 536, the third count 536, or combinations thereof.In one example, to diagnose degradation abnormality, the first count 534 may be compared to a first count threshold, the second count 536 may be compared to a second count threshold, and the third count 538 may be compared to a third count threshold. The first count threshold may be greater than the second and third count thresholds, but less than the sum of the second and third count thresholds.The second and third count threshold values may be the same or different. For example, at certain intersections, the measurements 518 may be more likely to exceed the control threshold 526 than the control threshold 524, or vice versa. Accordingly, one of the second and third count threshold values may be greater or less than the other of the second and third count threshold values to increase sensitivity to and facilitate detection of a specific type of degradation abnormality. In some examples, a type of degradation abnormality may be identified based on which of the first and second thresholds has been exceeded. For example, a first type of degradation abnormality may be diagnosed in response to the second count 536 exceeding the second count threshold while a second type of degradation abnormality is diagnosed in response to the third count 538 exceeding the third count threshold.While determining intermitencies may be based on simply exceeding a count corresponding to one of the control thresholds, determining intermitencies may also be accomplished using other methods. For example, it may be desirable to detect an intermittant in response to any instances that are 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, an intermittant 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 indicate a relatively rapidly changing value indicative of an intermittant (i.e., detecting a rate of change outside an expected range of rates of change).In still other examples, one or more of the count values 532 may be selectively reset, reduced, or otherwise adjusted. For example, the count values 532 may correspond to only a predetermined subset of the measurements 518, such as the most recent p measurements 518 (where p is a calibrateable value that may be different for each of the count values 532), only the measurements 518 from a predetermined period of time (e.g., the previous month, the previous two month period, etc.), and so forth. In another example, one or more of the counts 532 may be reset (e.g., set to 0) or reduced in response to a determination that the measurements 518 for a predetermined reset period or number of samples have not exceeded any of the control thresholds 524 and 526 (e.g., the measurements 518 in the last three months, during the last twenty samples, etc., have not exceeded any of the control thresholds 524 and 526). One or more of the count values 532 may also be reset after maintenance or replacement of various parts.FIG. 6 is a flow chart generally illustrating steps of an example method 600 for detecting degradation interferences in accordance with 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., the controller 100), one or more processors, or one or more processing devices (e.g., the processor 102), and / or other circuitry. In an example, one or more processors are configured to execute instructions stored in memory to perform methods 600.At 604, one or more measurements indicative of an electrical connection SOH are generated and received. Measurements may include, but are not limited to, one or more resistors associated with the electrical connection 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 a resistance of the electrical connection is calculated based on the current and the response.At 608, one or more adaptive control thresholds are calculated based on the measurements. In one example, an upper and a lower control threshold are calculated based on the average of a subset of the measurements and an offset that is added to and subtracted from the average, respectively, as described herein. The upper and lower control thresholds define an adaptive threshold window.At 612, a measurement (e.g., a current or most recent measurement) is compared to the upper and lower control thresholds. At 616, one or more frequency counts are updated in response to the comparison between the measurement and the upper and lower control thresholds. At 620, the one or more frequency counts are compared to respective count thresholds.At 624, one or more actions are taken in response to one or more of the frequency counts exceeding a respective count threshold. In one example, one or more flags or other indicators are stored, generated, etc. For example, a notification or other indicator may be provided to a driver or user, a manufacturer, a dealer, a service facility, etc. In one example, the notification is provided to the driver or user via a display or interface in the vehicle (e.g., a display of an infotainment system or other display on the dashboard), a mobile device, etc. For example, the notification (e.g., an engine light or other indicators) may indicate that the vehicle is to be serviced, recommending the driver or user to plan service to review and replace or repair components of the electrical connection, electrical power system, etc.In another example, the notification may indicate that one or more predicted values for the electrical connection SOH (e.g., a cumulative state calculation, a remaining useful life calculation, etc.) are inaccurate due to degradation intelligence. In examples where a driver or other entity is provided with different SOH values or indicators, such value or indicator may be retained (e.g., not provided to the driver) in response to one or more of the frequency counts exceeding the respective count threshold. Because the accurate determination of the SOH (and prediction of the future SOH) may be difficult in the presence of various intersections, in some examples, 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 state cannot be reliably predicted. Corresponding data may be sent to a remote server or cloud computing system, diagnostic tools (e.g., OBDII readers or other diagnostic devices) locally attached to the vehicle, etc. for remote analysis.In another example, control of one or more vehicle operating parameters (e.g., current provided to the engine or controller, etc.) may be adjusted under various conditions (e.g., when a measured temperature of the vehicle or vehicle system is above a threshold). For example, in response to detecting degradation abnormality, various parameters may be controlled (e.g., the current provided to the motor) to minimize additional wear of the electrical system and avoid failure.The above is intended to illustrate the principles and various embodiments of the present invention. Numerous variations and modifications will be apparent to those skilled in the art once having fully understood the above disclosure. It is intended to interpret the following claims as including all such variations and modifications.The word "example" is used herein to serve as an example, instance, or illustration. Any aspect or design described herein as an "example" is not necessarily to be considered preferred or advantageous over other aspects or designs. Rather, the use of the word "example" is intended to represent concepts in a concrete manner. As used in this application, the term "or" is intended to mean an inclusive "or" rather than an exclusive "or.". That is, unless otherwise stated or clear from context, "X includes A or B" is intended to mean any of the natural inclusive permutations. That is, when X includes A; X includes B; or X includes both A and B, then "X includes A or B" is satisfied in each of the above cases. Moreover, the articles "a" and "an" as used in this application and the appended claims should generally be construed to mean "one or more" unless otherwise stated or clearly understood from the context to refer to a singular form. Moreover, the use of the term "implementation" or "an implementation" does not mean that it is the same embodiment or implementation unless described as such.Implementations 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, computers, intellectual property (IP) cores, application specific integrated circuits (ASICs), programmable logic arrays, optical processors, programmable logic controllers, microcode, microcontrollers, servers, microprocessors, digital signal processors, or any other suitable circuit. In the claims, the term "processor" is to be understood to include any of the foregoing hardware, either alone or in combination. The terms "signal" and "data" are used interchangeably.As used herein, the term module may include a packaged functional hardware unit designed for use with other components, a series of instructions executable by a controller (e.g., a processor executing software or firmware), processing circuitry configured to perform a particular function, and a self-contained hardware or software component interfacing with a larger system. A module may include, for example, an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), a circuit, a digital logic circuit, an analog circuit, a combination of discrete circuits, gates, and other types of hardware, or a combination thereof. In other embodiments, a module may include a memory storing instructions executable by a controller to implement a feature of the module.Further, in one aspect, the systems described herein may be implemented, for example, using a general purpose computer or a general purpose processor having a computer program that, when executed, executes any of the methods, algorithms, and / or instructions described herein. Additionally or alternatively, for example, a dedicated computer / processor may be used that includes other hardware for executing the methods, algorithms, or instructions described herein.Further, all or part of the implementations of the present disclosure may take the form of a computer program product accessible from, for example, a computer-usable or computer-readable medium. A computer-usable or computer-readable medium may be any device that can, for example, tangibly contain, store, communicate, or transport the program for use by or in connection with any processor. The medium may be, for example, an electronic, magnetic, optical, electromagnetic, or semiconductor device. Other suitable media are also available.The above-described embodiments, implementations, and aspects have been described in order to allow easy understanding of the present invention and do not limit the present invention. Rather, the invention is intended to cover various modifications and equivalent arrangements included within the scope of the appended claims, which scope is to be construed as broadly as possible to include all modifications and equivalent structures which are legally permitted.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedUS 63 / 542,437

[0001] US 17 / 733,434

[0013]

Claims

A method for detecting degradation interferences 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, the input 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; in response to the comparison between the first measurement and the at least one adaptive control threshold, determining whether the electrical connection has a degradation interference; and performing at least one action in response to determining that the electrical connection has the degradation interference.The method of claim 1, wherein calculating the at least one adaptive control threshold includes calculating a first adaptive control threshold and a second adaptive control threshold defining a threshold window.The method of claim 2, wherein comparing the first measurement includes comparing the first measurement to the first adaptive control threshold and the second adaptive control threshold.The method of claim 3, further comprising determining that the electrical connection has the degradation inductance in response to the first measurement being greater than the first adaptive control threshold or less than the second adaptive control threshold.The method of claim 4, further comprising counting a number of times at which one of the plurality of measurements is either greater than the first adaptive control threshold or less than the second adaptive control threshold, and determining that the electrical connection has the degradation inductance based on the counted number of times.The method of claim 5, further comprising determining that the electrical connection has degradation inductance in response to a comparison between the counted number of times and at least one count threshold.The method of claim 1, further comprising calculating the at least one adaptive control threshold based on (i) an average of a predetermined number of the plurality of measurements and (ii) an offset.The method of claim 1, further comprising obtaining the resistance by applying 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.The method of claim 8, wherein the sinusoidal current is a non-torque producing current.The method of claim 1, wherein the steering system is an electronic power steering (EPS) system and the electrical connection is an electrical connection between a power supply and a motor of the EPS system.The method of claim 1, wherein performing the at least one action includes at least one of: generating and displaying an indicator in response to determining that the electrical connection has the degradation inductance; and controlling at least one operating parameter of the vehicle in response to determining that the electrical connection has the degradation inductance.A system for detecting degradation interferences 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, the input indicative of a plurality of measurements of the resistance; and a controller configured to calculate, based on the received input, at least one adaptive control threshold, compare a first measurement of the plurality of measurements to the at least one adaptive control threshold, in response to the comparison between the first measurement and the at least one adaptive control threshold, determine whether the electrical connection has degradation interference, and perform at least one action in response to determining that the electrical connection has degradation interference.The system of claim 12, wherein calculating the at least one adaptive control threshold includes calculating a first adaptive control threshold and a second adaptive control threshold defining a threshold window.The system of claim 13, wherein comparing the first measurement includes comparing the first measurement to the first adaptive control threshold and the second adaptive control threshold.The system of claim 14, wherein the controller is further configured to determine that the electrical connection has the degradation discontinuity in response to the first measurement being greater than the first adaptive control threshold or less than the second adaptive control threshold.The system of claim 15, wherein the controller is further configured to count a number of times at which one of the plurality of measurements is either greater than the first adaptive control threshold or less than the second adaptive control threshold, and determine that the electrical connection has the degradation abnormality based on the counted number of times.The system of claim 16, wherein the controller is further configured to determine that the electrical connection has the degradation inductance in response to a comparison between the counted number of times and at least one count threshold.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 of a predetermined number of the plurality of measurements and (ii) an offset.The system of claim 12, wherein the controller is further configured to obtain the resistance by applying 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.The system of claim 12, wherein the steering system is an electronic steering (EPS) system and the electrical connection is an electrical connection between a power supply and a motor of the EPS system.

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