Camera monitor system wing position controller

Abstract

A vehicle sensor wing position controller monitors current supplied to the motor during deployment and based upon the current determines whether the sensor wing has reached the deployed position. A current spike is generated when the at least one stop is encountered or when another obstacle is encountered. The profile of the current spike is compared to a known slope or profile. If there is a sufficient match, then it is determined that the deployed position was reached. In another example, current ripples generated during operation of the motor are counted. If the number of current ripples counted reaches a threshold, then it is determined that the sensor wing has reached the deployed position. The two techniques can be used in combination.

Description

CAMERA MONITOR SYSTEM WING POSITION CONTROLLERBACKGROUND

[0001] Camera monitor systems on vehicles are becoming an increasingly common substitute for traditional side and rear-view mirrors. One or more cameras mounted on the vehicle provide video to one or more displays visible to the vehicle’s driver. A side view camera, for example, is often mounted at the end of a sensor wing pivotably mounted to a base that is fixed to the vehicle. The wing is pivotable between a retracted, home position adjacent the vehicle and a deployed, use position away from the vehicle. An electric motor may drive the wing between the home position and the use position. Sensors or switches can be used to confirm to a controller whether the wing is in the home position or in the use position; however, additional sensors or switches add cost and complexity to the design.SUMMARY

[0002] A vehicle sensor wing position controller according to one example disclosed herein includes a housing rotatable relative to a base between the retracted position and the deployed position. A motor is coupled to the housing to selectively move the housing between the retracted position and the deployed position. At least one stop resists rotation of the housing past the deployed position. The vehicle sensor wing position controller monitors current supplied to the motor during deployment and based upon the current determines whether the sensor wing has reached the deployed position.

[0003] In one example, a current spike is generated when the at least one stop is encountered. To distinguish the at least one stop from another obstacle (such as a wall), the slope or profile of the current spike is compared to a known slope or profile. If there is a sufficient match, then it is determined that the deployed position was reached. If there is not asufficient match, then it is determined that an obstacle was encountered by the sensor wing. A warning may be generated.

[0004] In another example, current ripples generated during operation of the motor are counted. If the number of current ripples counted reaches a threshold, then it is determined that the sensor wing has reached the deployed position. If the sensor wing stops (e.g. the current spikes) before the threshold number of current ripples has been counted, then it is determined that the sensor wing encountered an obstacle. A warning may be generated.

[0005] In other example, the current spike and current ripple techniques may be used in combination. For example, the motor is stopped when a current spike is detected. If the profile of the current spike sufficiently matches the known profile, then the number of current ripples counted is compared to the threshold. Only if the profile matches sufficiently and the number of current ripples counted reaches the threshold is it determined that the sensor wing has reached the deployed position. Otherwise, it is determined that the sensor wing encountered an obstacle. A warning may be generated.

[0006] The two techniques can be combined in other ways. For example, the motor can be switched off in response to detecting the current spike or in response to the number of current ripples reaching the threshold, whichever occurs first.

[0007] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller including: a base; a housing for supporting a vehicle sensor wing thereon, the housing rotatable relative to the base between a first position and a second position; a motor coupled to the housing to selectively cause rotation of the housing relative to the base; at least one stop resisting rotation of the housing relative to the base past the second position; at least one processor, and at least one storage storing instructions, which when executed by the at leastone processor cause the vehicle sensor wing position controller to: a) monitor current to the motor while the motor is moving the housing between the first position and the second position; b) detect a current spike during step a); c) compare a profile of the current spike to a known profile; and d) determine whether the vehicle sensor wing reached the second position or encountered an obstacle; wherein step d) is performed based upon the comparison of step c).

[0008] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

[0009] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller wherein the instructions further cause the vehicle sensor wing position controller to: e) count ripples in the current supplied to the motor during step a); and f) compare the ripples counted in step e) to a threshold; wherein step d) is performed based upon step f).

[0010] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller wherein step e) is performed until step b).

[0011] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

[0012] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

[0013] In some aspects, the techniques described herein relate to a method for monitoring a position of a vehicle sensor wing movable between a retracted position and a deployed position including: a) supplying power to a motor coupled to the vehicle sensor wing;b) during step a) monitoring a current supplied to the motor; c) detecting a spike in the current supplied to the motor during step b); d) comparing a profile of the spike to a known profile; and e) determining whether the vehicle sensor wing reached the deployed position or encountered an obstacle; wherein step e) is performed based upon step d).

[0014] In some aspects, the techniques described herein relate to a method further including: f) detecting ripples in the current supplied to the motor during step a); g) counting the ripples detected in step f); and h) comparing the ripples counted in step g) to a threshold; wherein step e) is performed based upon step h).

[0015] In some aspects, the techniques described herein relate to a method wherein the step of counting the ripples in step g) is performed during step a) until step c).

[0016] In some aspects, the techniques described herein relate to a method further including: i) switching off power supplied to the motor based upon step c); wherein step h) is performed after step i).

[0017] In some aspects, the techniques described herein relate to a method wherein it is determined in step e) that an obstacle was encountered prior to reaching the deployed position based upon the ripples counted being less than the threshold.

[0018] In some aspects, the techniques described herein relate to a method wherein it is determined in step e) that the vehicle sensor wing reached the deployed position based upon the ripples counted reaching the threshold.

[0019] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller including: a base; a housing for supporting a vehicle sensor wing thereon, the housing rotatable relative to the base between a first position and a second position; a motor coupled to the housing to selectively cause rotation of the housing relative to the base; at leastone stop resisting rotation of the housing relative to the base past the second position; at least one processor, and at least one storage storing instructions, which when executed by the at least one processor cause the vehicle sensor wing position controller to: a) monitor current to the motor while the motor is moving the housing between the first position and the second position; b) count ripples in the current supplied to the motor during step a); c) compare the ripples counted in step b) to a threshold; and d) determine whether the vehicle sensor wing reached the second position or encountered an obstacle; wherein step d) is performed based upon the comparison of step c).

[0020] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

[0021] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller wherein step b) is performed until a current spike is detected.

[0022] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

[0023] In some aspects, the techniques described herein relate to a vehicle sensor wing position controller further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

[0024] In some aspects, the techniques described herein relate to a method for monitoring a position of a vehicle sensor wing movable between a retracted position and a deployed position including: a) supplying power to a motor coupled to the vehicle sensor wing; b) during step a) monitoring a current supplied to the motor; c) counting ripples in the currentsupplied to the motor during step a); and d) determining whether the vehicle sensor wing reached the deployed position or encountered an obstacle; wherein step d) is performed based upon step c).

[0025] In some aspects, the techniques described herein relate to a method wherein the step of counting the ripples in step c) is performed until a current spike is detected.

[0026] In some aspects, the techniques described herein relate to a method further including: e) switching off power supplied to the motor based upon step d); wherein step e) is performed after step e).

[0027] In some aspects, the techniques described herein relate to a method wherein it is determined in step d) that an obstacle was encountered prior to reaching the deployed position based upon the ripples counted in step c) being less than a threshold.

[0028] In some aspects, the techniques described herein relate to a method wherein it is determined in step c) that the vehicle sensor wing reached the deployed position based upon the ripples counted in step c) reaching a threshold.BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is an exploded view of a camera monitor system for a vehicle.

[0030] Figure 2 is a graph of the current drawn by the motor of Figure 1 while the wing of Figure 1 is moving to the extending position.

[0031] Figure 3 is a greatly enlarged view of the current signal of Figure 2 during time tnom-

[0032] Figure 4 shows several simplified schematics of the motor of Figure 1 to demonstrate the generation of the ripple current.

[0033] Figure 5 is a flowchart of one possible method for determining whether the vehicle sensor wing of Figure 1 has reached a fully deployed, use position.

[0034] Figure 6 is a flowchart of a method for discontinuing power to the motor of Figure 1 that could be operated in parallel with the method of Figure 5.DETAILED DESCRIPTION

[0035] Figure 1 is an exploded view of a camera monitor system 10 for a vehicle (not shown). The camera monitor system 10 includes a central shaft 12 having a base 13 fixed to the vehicle. A housing 14 is pivotably mounted to the central shaft 12 such that the central shaft 12 passes through the housing 14. A cover 16 is configured to substantially enclose the other components with the housing 14.

[0036] A cam ring 18 is fixed to the central shaft 12 below the housing 14. The central shaft 12 extends through the cam ring 18. The cam ring 18 includes at least one stop 19 that engages one or more complementary stops on an underside of the housing 14 to limit rotation of the housing 14 relative to the central shaft 12.

[0037] A wing 20 (not shown to scale) has at least one camera 22 mounted thereto, typically proximate an outer end thereof. An inner end of the wing 20 is secured to the housing 14. Rotation of the housing 14 relative to the central shaft 12 moves the wing 20 and the at least one camera 22 between a home position (a first or retracted position) adjacent the vehicle and a use position (a second or deployed position) away from the vehicle. When the housing 14 is moved to the use position, at least one stop on the underside of the housing 14 contacts the at least one stop 19 on the cam ring 18.

[0038] An electric motor 24 is mounted to a frame 26 secured to the housing 14. A power supply 28 supplies DC power to the electric motor 24 and is controlled by a controller 30 which may include one or more processors suitably programmed to perform the functions described herein.

[0039] A spacer 32 positions the electric motor 24 within the cover 16. A motor shaft 25 extends through a motor guide 34 and is fixed to a motor worm 36. The motor worm 36 engages a worm gear 38 fixed to a worm gear shaft 40. A worm wheel 42 is positioned at the end of the worm gear shaft 40 and retained by a worm gear washer 44. The camera monitor system 10 further includes a bearing spring 46.

[0040] The worm gear 38 engages a clutch gear 48 that is rotatably received on the central shaft 12. The clutch gear 48 includes at least one projection 49 received in at least one complementary recess 51 in a detent ring 50. The clutch gear 48 and detent ring 50 provide a breakaway function to decouple the clutch gear 48 rotatably from the housing 14, such as in the event of an impact to the wing 20. This decouples the electric motor 24 from the housing 14 and the force of any such impact.

[0041] A stop ring 52 is biased toward the clutch gear 48 by a clutch spring 54, both received on the central shaft 12. A fixing washer 56 retains the clutch spring 54 on the central shaft 12.

[0042] Referring to Figure 2, as the power supply 28 supplies a voltage (V) to the electric motor 24 as shown in the upper graph, the current (A) fluctuates as shown in the lower graph of Figure 2. As shown, the current spikes at startup, then remains substantially constant during the time (tnOm) of travel of the wing 20 (Figure 1), and then spikes again when the housing 14 contacts the at least one stop 19 on the central shaft 12. The power supply 28 and / or controller 30 detects the current spike after time tnOm at the end of travel and switches off the power supply 28. The power supply 28 and / or controller 30 may also monitor the slope of the current spike after time tnOm and compare the slope to a known profile that should be generated when the at least one stop on the housing 14 engages the at least one stop on the central shaft12. If the slope / profile does not match sufficiently, then the controller 30 determines that some other obstacle may have been encountered (other than end of travel stops), and a warning may be generated. An analog-to-digital converter may convert the measured current levels to a digital signal readable by the controller 30.

[0043] Figure 3 is a greatly enlarged view of the current signal of Figure 2 during time tnom. As shown, there are very small-amplitude ripples on top of the DC signal. These current ripples are generated at a constant count per mechanical rotation of the electric motor 24. The ripple count per mechanical rotation is independent of temperature, voltage, engine speed, and manufacturing variations in the electric motor 24 or other components. The power supply 28 and / or controller 30 count the ripples during travel of the wing 20 from the home position to the use position. Suitable ripple counters are known, such as the AN3049 available from Microchip Technology, Inc. After the current spikes and the power supply 28 is switched off, the number of current ripples that were counted during travel is compared to a threshold. If the number of current ripples reached the threshold, then the controller 30 determines that the wing 20 fully reached the fully-deployed, use position. If the number of current ripples did not reach the threshold, then the controller 30 determines that the wing 20 encountered an obstacle prior to fully reaching the fully-deployed, use position.

[0044] It is possible that the housing 14 could contact an obstacle (e.g. a wall) that may generate a slope or profile similar to the known profile of the at least one stop on the housing 14 engaging the at least one stop 19 on the central shaft 12. Counting the current ripples and comparing them to the threshold confirms whether the wing 20 reached the use position or whether it encountered an obstacle that generated a similar current spike.

[0045] The number of current ripples can be compared to the threshold in combination with comparing the slope or profile of the current spike to a known profile. In one example, the number of current ripples counted is only compared to the threshold after the slope or profile of the current spike sufficiently matches the known profile. If the number of current ripples is below the threshold, then it is determined that an obstacle was encountered and a warning is generated to the driver. If the number of current ripples reached the threshold, then the controller 30 determines that the wing 20 and at least one camera 22 are in the use position.

[0046] Alternatively, the power supply 28 may be shut off as soon as either the number of current ripples reaches the threshold or the current spikes with a profile to match the known profile.

[0047] Upon power-up or after a power interruption that occurs during folding or unfolding of the wing 20, or if the wing 20 is moved manually, the controller 30 causes the wing 20 to rehome to the home position and then move back to the use position. The controller 30 may also perform small movements and check the DC current to verify if it is already on the beginning or end of travel.

[0048] A circuit in the power supply 28 converts the current ripple signal to a digital signal without the use of a direct analog to digital conversion. For example, the circuit may convert the ripples to a square wave signal, and the square waves can easily be counted, such as with an interrupt pin. The use of PCB traces to measure the ripple current avoiding the use of discrete or SMT shunt resistors

[0049] Determining the position of the wing 20 without additional sensors or switches is an advantage in terms of cost, durability and mechanical complexity.

[0050] Every Brushed DC motor when moving generates a so called “ripple current” due to the movement / transition of the commuter plates with its brushes. The number of current pulses generated by the rotation of the motor is deterministic (# of pulses / turn) and can be used to infer the number of turns of a motor while it was powered. The ripple current appears as a millivolt range, AC current over the motor DC current.

[0051] Referring to Figure 4, the small current ripple is produced during motor rotation and defined as the low-amplitude current alternation, riding on the DC voltage supply. This current ripple is a periodic variation in current created by the rotor movement when it connects and disconnects rotor coils to the power supply via the brushes. When the electric motor 24 is turning, the brushes short-out adjacent commutator segments that result in a current circulating between the segments. This causes the Back-EMF of the commutator segments to be shorted out, thus producing short duration high-voltage pulses on the motor terminals. The high-voltage pulses lower the impedance of the wingature, thus causing the overall current to rise and generate a current ripple. The periodic shifting of a brush from one coil to another produces the periodic current ripple. Again, the number of ripples will be proportional the number of rotations of the electric motor 24, independent of temperature, voltage, engine speed, and other variations or tolerances.

[0052] Figure 5 is a flowchart of one possible method for determining whether the vehicle sensor wing 20 of Figure 1 has reached a fully deployed, use position. Referring to Figures 1 and 5, in step 110, the power supply 28 begins supplying power to the electric motor 24. In step 112, the current supplied to the electric motor 24 is monitored. In step 114, the current ripples are counted. In step 116, a current spike is detected in the current supplied to the electric motor 24. Based upon the detection of the current spike (of sufficient magnitudeand / or slope), the profile of the spike (Figure 2) is compared to a known profile in step 120. The known profile could simply be a slope (or slope and magnitude) or could be a more complicated profile including a changing slope over time.

[0053] In step 122, it is determined whether the profile of the current spike sufficiently matches the known profile. If not, it is determined that an obstacle (other than end of travel stop 19) has been contacted and a warning is sent to the driver of the vehicle that the vehicle sensor wing 20 is not in a fully deployed position.

[0054] If in step 122, it is determined that the profile of the current spike sufficiently matches the known profile, then in step 126, the current ripples that have been counted while power was supplied to the electric motor 24 until the current spike was detected is compared to a threshold. If it is determined in step 128 that the threshold number of ripples is not reached, then it is determined again in step 124 that an obstacle (other than end of travel stop 19) has been contacted by wing 20 and a warning is sent to the driver of the vehicle that the vehicle sensor wing 20 is not in a fully deployed position.

[0055] If in step 126 it is determined that the threshold number of ripples was counted between the initiation of power to the electric motor 24 and the current spike detection in step 116, then it is determined in step 130 that the fully deployed, use position has been reached.

[0056] Figure 6 is a flowchart of a method for discontinuing power to the motor 24 of Figure 1 that could be operated in parallel with the method of Figure 5. Again, in step 110, the power supply 28 begins supplying power to the electric motor 24. In step 112, the current supplied to the electric motor 24 is monitored. In step 114, the current ripples are counted. In step 115, which operates in parallel with step 114, occurrence of a current spike is monitored in the current supplied to the electric motor 24.

[0057] Again the number of current ripples is compared to a threshold in step 126. If the threshold is not reached in step 128, then current ripples continue to be counted in step 114. If the threshold is reached in step in step 128, then it is determined that the deployed position has been reached in step 130 and power to the electric motor 24 is discontinued in step 118.

[0058] If, during the performance of steps 114, 126 and 128, a current spike is detected in step 116, then power to the electric motor 24 is discontinued in step 118. The method then returns to step 120 of Figure 5.

[0059] In accordance with the provisions of the patent statutes and jurisprudence, exemplary configurations described above are considered to represent a preferred embodiment of the invention. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope. Alphanumeric identifiers on method claim steps or executed operations are for ease of reference in dependent claims only and do not signify a required sequence unless other explicitly recited in the claims.

Claims

CLAIMSWHAT IS CLAIMED IS:

1. A vehicle sensor wing position controller comprising: a base; a housing for supporting a vehicle sensor wing thereon, the housing rotatable relative to the base between a first position and a second position; a motor coupled to the housing to selectively cause rotation of the housing relative to the base; at least one stop resisting rotation of the housing relative to the base past the second position; at least one processor, and at least one storage storing instructions, which when executed by the at least one processor cause the vehicle sensor wing position controller to: a) monitor current to the motor while the motor is moving the housing between the first position and the second position; b) detect a current spike during step a); c) compare a profile of the current spike to a known profile; and d) determine whether the vehicle sensor wing reached the second position or encountered an obstacle; wherein step d) is performed based upon the comparison of step c).

2. The vehicle sensor wing position controller of claim 1, further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

3. The vehicle sensor wing position controller of claim 2, wherein the instructions further cause the vehicle sensor wing position controller to: e) count ripples in the current supplied to the motor during step a); andf) compare the ripples counted in step e) to a threshold; wherein step d) is performed based upon step f).

4. The vehicle sensor wing position controller of claim 3 wherein step e) is performed until step b).

5. The vehicle sensor wing position controller of claim 3 or 4, further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

6. The vehicle sensor wing position controller of any preceding claim, further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

7. A method for monitoring a position of a vehicle sensor wing movable between a retracted position and a deployed position including: a) supplying power to a motor coupled to the vehicle sensor wing; b) during step a) monitoring a current supplied to the motor; c) detecting a spike in the current supplied to the motor during step b); d) comparing a profile of the spike to a known profile; and e) determining whether the vehicle sensor wing reached the deployed position or encountered an obstacle; wherein step e) is performed based upon step d).

8. The method of claim 7, further including: f) detecting ripples in the current supplied to the motor during step a); g) counting the ripples detected in step f); and h) comparing the ripples counted in step g) to a threshold; wherein step e) is performed based upon step h).

9. The method of claim 8, wherein the step of counting the ripples in step g) is performed during step a) until step c).

10. The method of claim 8 or 9, further including: i) switching off power supplied to the motor based upon step c); wherein step h) is performed after step i).

11. The method of any one of claims 8 to 10, wherein it is determined in step e) that an obstacle was encountered prior to reaching the deployed position based upon the ripples counted being less than the threshold.

12. The method of any one of claims 8 to 11, wherein it is determined in step e) that the vehicle sensor wing reached the deployed position based upon the ripples counted reaching the threshold.

13. A vehicle sensor wing position controller comprising: a base; a housing for supporting a vehicle sensor wing thereon, the housing rotatable relative to the base between a first position and a second position; a motor coupled to the housing to selectively cause rotation of the housing relative to the base; at least one stop resisting rotation of the housing relative to the base past the second position; at least one processor, and at least one storage storing instructions, which when executed by the at least one processor cause the vehicle sensor wing position controller to: a) monitor current to the motor while the motor is moving the housing between the first position and the second position;b) count ripples in the current supplied to the motor during step a); c) compare the ripples counted in step b) to a threshold; and d) determine whether the vehicle sensor wing reached the second position or encountered an obstacle; wherein step d) is performed based upon the comparison of step c).

14. The vehicle sensor wing position controller of claim 13, further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

15. The vehicle sensor wing position controller of claim 13 or 14, wherein step b) is performed until a current spike is detected.

16. The vehicle sensor wing position controller of claim 15, further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

17. The vehicle sensor wing position controller of any one of claims 13 to 16, further including the vehicle sensor wing mounted to the housing, a camera mounted to the vehicle sensor wing.

18. A method for monitoring a position of a vehicle sensor wing movable between a retracted position and a deployed position including: a) supplying power to a motor coupled to the vehicle sensor wing; b) during step a) monitoring a current supplied to the motor; c) counting ripples in the current supplied to the motor during step a); and d) determining whether the vehicle sensor wing reached the deployed position or encountered an obstacle; wherein step d) is performed based upon step c).

19. The method of claim 18, wherein the step of counting the ripples in step c) is performed until a current spike is detected.

20. The method of claim 18 or 19, further including: e) switching off power supplied to the motor based upon step d); wherein step e) is performed after step e).

21. The method of any one of claims 18 to20, wherein it is determined in step d) that an obstacle was encountered prior to reaching the deployed position based upon the ripples counted in step c) being less than a threshold.

22. The method of any one of claims 18 to 21, wherein it is determined in step c) that the vehicle sensor wing reached the deployed position based upon the ripples counted in step c) reaching a threshold.

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