Method and device for detecting a usability of a control device

Abstract

A method for recognizing a usability of a control device of a safety device in a vehicle includes: applying a voltage to the control device; acquiring a voltage curve or a current curve at the control device; and recognizing a usability of the control device as a function of the acquired voltage curve or of the acquired current curve. In particular, the correct polarity of an inductive actuator having a freewheeling diode is recognized, because in the case of incorrect polarity the inductive actuator is bridged by the freewheeling diode.

Claims

1. A method for recognizing a usability of a control device of a safety device in a vehicle, comprising: applying a voltage to the control device, which has a preferred direction of current flow; acquiring a high-side voltage curve and a low-side voltage curve at the control device; and recognizing a usability of the control device; wherein the recognizing of the usability of the control device includes determining that the control device, which has a preferred direction of current flow, has been installed in a correct direction, so that current can flow in the preferred direction, wherein the control device includes a free-wheeling diode in parallel with a control element, wherein if the high-side voltage curve at a high-side switch, which is coupled on a high side of the control device, rises faster than the low-side voltage curve at a low-side switch, which is coupled on a low side of the control device, it is recognized that the safety device has been connected with a correct polarity, and the usability of the control device is recognized, since the current flows through the control element and not through the free-wheeling diode, wherein if the high-side voltage curve at the high-side switch and the low-side voltage curve at the low-side switch rises with about the same speed, then the safety device has been connected with a reversed or incorrect polarity, and the usability of the control device is not recognized, since the current does not flow through the control element, but instead flows through the freewheeling diode that does not block the current because the control device has been installed or connected with reversed polarity, wherein the high-side switch is coupled to a blocking end of the free-wheeling diode and the low-side switch is coupled to the other end of the free-wheeling diode, the low-side switch being coupled to ground, wherein the high-side switch is situated upstream, in a direction of a current flow, from the control device having the control element, and wherein the low-side switch is situated downstream, in a direction of the current flow, from the control device having the control element.

2. The method as recited in claim 1, wherein the voltage from a first energy source separate from an energy source of the vehicle is applied in the applying of the voltage to the control device, the method further comprising: charging the first energy source.

3. The method as recited in claim 2, wherein the first energy source is connected to the energy source of the vehicle through a first switch, and wherein in the step of charging, the first energy source is charged through the closed first switch.

4. The method as recited in claim 3, wherein the connection to the energy source of the vehicle is disconnected by opening of the first switch after the charging of the first energy source.

5. The method as recited in claim 2, wherein the control device has at least one of a time boundary value and a current boundary value, wherein the control device is not triggered if the voltage is applied to the control device for a time period not greater than the time boundary value, and wherein the control device is not triggered when a current flowing through the control device is not greater than the current boundary value, the method further comprising: disconnecting the applied voltage of one of: (i) after the time period not greater than the time boundary value, and (ii) before the current flowing through the control device reaches the current boundary value.

6. The method as recited in claim 5, wherein the control device is connected to the high-side switch, and wherein the voltage is applied to the control device via the high-side switch in the closed state in the step of applying the voltage to the control device.

7. The method as recited in claim 6, wherein the control device is configured to be selectively triggered by the high-side switch and the low-side switch, and wherein a triggering of the control device is prevented if the the low-side switch is open.

8. The method as recited in claim 2, wherein the usability of the control device is recognized when the acquired voltage curve has a characteristic rise in voltage.

9. The method as recited in claim 8, wherein the acquired voltage curve is compared in the recognizing step to a voltage boundary value.

10. The method as recited in claim 9, wherein the usability of the control device is recognized as not present when the acquired voltage curve does not have the characteristic rise in voltage.

11. The method as recited in claim 9, wherein the usability of the control device is recognized if a correct polarity of the control device is present.

12. A device for recognizing a usability of a control device of a safety device in a vehicle, comprising: a voltage applying arrangement to apply a voltage to the control device, which has a preferred direction of current flow; an acquiring arrangement to acquire a high-side voltage curve and a low-side voltage curve at the control device; and a recognizing arrangement to recognize a usability of the control device; wherein the recognizing of the usability of the control device includes determining that the control device, which has a preferred direction of current flow, has been installed in a correct direction, so that current can flow in the preferred direction, wherein the control device includes a free-wheeling diode in parallel with a control element, wherein if the high-side voltage curve at a high-side switch, which is coupled on a high side of the control device, rises faster than the low-side voltage curve at a low-side switch, which is coupled on a low side of the control device, it is recognized that the safety device has been connected with a correct polarity, and the usability of the control device is recognized, since the current flows through the control element and not through the free-wheeling diode, wherein if the high-side voltage curve at the high-side switch and the low-side voltage curve at the low-side switch rises with about the same speed, then the safety device has been connected with a reversed or incorrect polarity, and the usability of the control device is not recognized, since the current does not flow through the control element, but instead flows through the freewheeling diode that does not block the current because the control device has been installed or connected with reversed polarity, wherein the high-side switch is coupled to a blocking end of the free-wheeling diode and the low-side switch is coupled to the other end of the free-wheeling diode, the low-side switch being coupled to ground, wherein the high-side switch is situated upstream, in a direction of a current flow, from the control device having the control element, and wherein the low-side switch is situated downstream, in a direction of the current flow, from the control device having the control element.

13. The device as recited in claim 12, further comprising: a first energy source for providing the voltage for application to the control device.

14. The device as recited in claim 13, further comprising: a safety switch; wherein the vehicle has a further energy source, and wherein the first energy source is selectively connected to the further energy source of the vehicle through the safety switch in the closed state to charge the first energy source.

15. The device as recited in claim 14, wherein: the control device has at least one of a time boundary value and a current boundary value, and the control device is not triggered if the voltage is applied to the control device for a time period not greater than the time boundary value, and the control device is not triggered when a current flowing through the control device is not greater than the current boundary value; and the first energy source has a capacitor storing at most a predefined amount of energy such that the voltage is able to be applied to the control device at least one of (i) for at most a time period corresponding to the time boundary value, and (ii) for at most a time period until a current which corresponds to the current boundary value flows through the control device.

16. The device as recited in claim 15, wherein the control device has the high-side switch and the low-side switch each configured to be selectively closed to control the safety device, and wherein the voltage applying arrangement to apply the voltage closes the high-side switch and does not close the low-side switch.

17. The device as recited in claim 16, wherein the first energy source is situated between the safety switch and the high-side switch.

18. The device as recited in claim 17, wherein the control device has at least one inductive electrical component.

19. The device as recited in claim 17, wherein the usability of the control device is recognized if a correct polarity of the control device is present.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 shows a diagram of a voltage/current curve.

(2) FIG. 2 shows a further diagram of a voltage/current curve.

(3) FIG. 3 shows a schematic diagram.

(4) FIG. 4 shows a diagram having boundary values for a current.

(5) FIG. 5a shows a further diagram of a voltage/current curve.

(6) FIG. 5b shows an enlarged region of a diagram of a voltage/current curve.

(7) FIG. 6a shows a further diagram of a voltage/current curve.

(8) FIG. 6b shows an enlarged region of a diagram of a voltage/current curve.

(9) FIG. 7 shows a further schematic diagram.

(10) FIG. 8 shows a flow diagram of the method.

DETAILED DESCRIPTION OF THE INVENTION

(11) FIG. 1 shows a diagram of an acquired voltage and current curve during the execution of the method according to the present invention by the device according to the present invention, if the control device or the actuator of the present invention has correct polarity.

(12) In the upper diagram, the curves are plotted over time of the current through the control device, or the actuator, and through the freewheeling diode. The solid line indicates the current curve through the control device or the actuator. The dashed line indicates the current curve through the freewheeling diode.

(13) In the lower diagram, the curves are plotted over time of the voltages at the separate energy source, e.g. an EMV capacitor, and at the second switch (HS), or high-side switch, as well as the voltage curve for the controlling of the second switch (HS), or high-side switch, and the third switch (LS), or low-side switch. Here, the solid line indicates the voltage curve at the separate energy source, e.g. an EMV capacitor, and the dashed line indicates the voltage curve at the second switch (HS), or high-side switch, and the dot-dash line indicates the voltage curve for the controlling of the second switch (HS), or high-side switch, and of the third switch (LS), or low-side switch, by a processing device (C).

(14) It can be seen clearly that at time t1 of the application of a voltage, there takes place a rise in voltage in the voltage curve at the second switch (HS), or high-side switch (lower diagram, dashed line). At the same time, it can be seen that a current begins to flow through the actuator (upper diagram, solid line). The current through the freewheeling diode does not show any significant value (upper diagram, dashed line). From this the usability of the control device, or of the actuator, can be recognized.

(15) FIG. 2 shows a diagram of an acquired voltage and current curve during execution of the method according to the present invention by the device according to the present invention, if the control device or the actuator of the present invention has been installed with wrong or reversed polarity.

(16) In the upper diagram, the curves are plotted over time of the current through the control device, or the actuator, and through the freewheeling diode. The solid line indicates the current curve through the control device or the actuator. The dashed line indicates the current curve through the freewheeling diode.

(17) In the lower diagram, the curves are plotted over time of the voltages at the separate energy source, e.g. an EMV capacitor, and at the second switch (HS), or high-side switch, as well as the voltage curve for the controlling of the second switch (HS), or high-side switch, and the third switch (LS), or low-side switch. Here, the solid line indicates the voltage curve at the separate energy source, e.g. an EMV capacitor, and the dashed line indicates the voltage curve at the second switch (HS), or high-side switch, and the dot-dash line indicates the voltage curve for the controlling of the second switch (HS), or high-side switch, and of the third switch (LS), or low-side switch, by a processing device (C).

(18) It can be seen clearly that at time t1 of the application of a voltage, there takes place no rise in voltage in the voltage curve at the second switch (HS), or high-side switch (lower diagram, dashed line). At the same time, it can be seen that a current begins to flow through the freewheeling diode (upper diagram, dashed line). The current through the control device, or the actuator, does not show any significant value (upper diagram, solid line). From this, it can be recognized that the control device, or the actuator, is not usable.

(19) FIG. 3 shows a schematic diagram of a device 300 according to the present invention that has been connected with correct polarity.

(20) Reference character 330 designates an energy reserve (ER), reference character 350 designates a first switch or safety switch (SVS), reference character 370 designates a separate energy source, here a capacitor for electromagnetic compatibility (EMV-C) of device 300, reference character 390 designates an assembly having a microcontroller (C) and a safety controller (SCON), and the required external wiring, reference character 320 designates a second switch, or high-side switch (HS), reference character 340 designates a third switch, or low-side switch (LS), reference character 360 designates a control device or actuator, and reference character 380 designates a ground potential.

(21) Control device or actuator 360 has at least one coil 361 and a freewheeling diode 362, as well as further mechanical elements necessary for controlling the safety devices.

(22) Assembly 390 is fashioned to control the first switch, or safety switch (SVS), 350, the second switch, or high-side switch, 320, and the third switch, or low-side switch, 340.

(23) In an embodiment of the method according to the present invention, first the first switch or safety switch (SVS) 350 is closed by assembly 390 in order to charge separate energy source 370, e.g. an EMV capacitor. When separate energy source 370, e.g. the EMV capacitor, has been charged, first switch or safety switch (SVS) 350 is opened. As a result, the control device, or actuator 360, can then be supplied with voltage only via separate energy source 370, e.g. the EMV capacitor. Subsequently, second switch 320 is closed by assembly 390. As a result, a voltage, provided by separate energy source 370, e.g. the EMV capacitor, is applied to actuator 360. At the same time, using a suitable method known from the existing art, voltage curves are acquired at high-side switch 320 and at low-side switch 340. The required measurement values of the voltage curves are forwarded to the microcontroller (C). The evaluation takes place in the microcontroller (C) in assembly 390 using suitable software or hardware circuitry. If the voltage curve at high-side switch 320 rises faster than the voltage curve at low-side switch 340, it can then be recognized that actuator 360 has been installed or connected with the correct polarity, and usability of actuator 360 can be recognized. If this is not the case, and the voltage curves at high-side switch 320 and at low-side switch 340 rise with the same speed, then actuator 360 has been installed or connected with reversed polarity. The current then flows not through coil 361, but rather through freewheeling diode 362. In this case, freewheeling diode 362 does not block, because the actuator has been installed or connected with reversed polarity.

(24) In the schematic diagram, it can be seen that freewheeling diode 362 is opposed to the direction of current flow. If, as the result of an applied voltage, current flows through control device or actuator 360, the current then flows through coil 361. Freewheeling diode 362 blocks the flow of current.

(25) FIG. 4 shows a diagram having current boundary values for a control device 360 of the present invention.

(26) Time t is plotted on the abscissa; current I on the ordinate. On the abscissa, time boundary values are plotted. On the ordinate, current boundary values are plotted.

(27) First boundary value t.sub.MaxNoFire on the abscissa designates a maximum time duration before a triggering is ensured not to take place even if a current flows through actuator 360 that would be minimally required for a triggering. Second boundary value t.sub.MinFire designates a minimum time duration for a minimum current that has to flow through actuator 360 in order for a triggering to occur. Third boundary value t.sub.MaxFire designates a maximum time duration for which a minimum current may flow through actuator 360 without it being possible for destruction of actuator 360 to occur.

(28) First boundary value I.sub.MaxNoFire on the ordinate designates a maximum current that may flow permanently through actuator 360 without the occurrence of a triggering. Second boundary value I.sub.MinFire designates a minimum current that has to flow through actuator 360 in order for a triggering to be able to occur. Third boundary value I.sub.MaxFire designates a maximum current that may flow through actuator 360 without it being possible for destruction of actuator 360 to occur.

(29) The six boundary values span regions. Region 410, hatched from the upper left to the lower right, designates a working region (non-triggering region) of the actuator, in which a triggering cannot occur. Cross-hatched region 420 designates a working region (gray region) in which it is not certain that a triggering will occur nor is it certain that no triggering will occur. Non-continuously hatched region 430 designates a working region (triggering region) in which it is certain that a triggering of actuator 360 will occur. Region 440, hatched from lower left to upper right, designates a working region (overload region) in which a destruction of actuator 360 can occur. Non-triggering region 410 also has a subregion 410a. In this region, the method according to the present invention is executed, or device 300 according to the present invention operates during the execution of the method according to the present invention.

(30) The method according to the present invention is executed in subregion 410a of working region 410. In this way, it is ensured that during execution of the method according to the present invention, an undesired triggering of actuator 360 cannot occur. For this purpose, for example separate energy source 370 is correspondingly dimensioned. The energy source cannot provide enough energy, or voltage, or current, to operate actuator 360 in a region other than subregion 410a of working region 410.

(31) FIG. 5a shows a diagram of an acquired voltage and current curve during execution of the method according to the present invention by the device according to the present invention, if the control device, or the actuator, of the present invention has been connected with correct polarity.

(32) In the upper diagram, the curves are plotted over time of the current through the control device, or the actuator, and through the freewheeling diode. The solid line indicates the current curve through the control device or the actuator. The dashed line indicates the current curve through the freewheeling diode.

(33) In the lower diagram, the curves are plotted over time of the voltage measured at the separate energy source, e.g. an EMV capacitor, and at the second switch (HS), or the high-side switch, as well as the voltage curve required for the controlling only of the second switch (HS), or high-side switch, as well as the voltage curve measured at the third switch (LS), or low-side switch. The thick solid line here indicates the voltage curve at the separate energy source, e.g. an EMV capacitor, and the dashed line indicates the voltage curve at the second switch (HS), or high-side switch, and the dot-dash line indicates the voltage curve for the controlling of only the second switch (HS), or high-side switch, by a processing device (C). The thin solid line indicates the voltage curve measured at the third switch (LS), or low-side switch.

(34) It can be seen clearly that at time t1 of the application of a voltage, a rise in voltage takes place in the voltage curve at the high-side switch (HS). A rise in voltage in the voltage curve at the low-side switch (LS) takes place more slowly. At the same time, it can be seen that a current begins to flow through the actuator. The current through the freewheeling diode does not have any significant value. From this, the usability of the control device, or actuator, is recognized.

(35) FIG. 5b shows an enlarged segment around the region around times t1 and t2. Here, the rises in voltage in the voltage curves at the high-side switch (HS) and low-side switch (LS) can be seen still more clearly.

(36) In FIG. 5b, it can be seen clearly that the rise in voltage at the low-side switch (LS) takes place more slowly than at the high-side switch (HS). Accordingly, the actuator is ready for use, because the current can flow through the coil of the actuator.

(37) FIG. 6a shows a diagram of an acquired voltage and current curve during execution of the method according to the present invention by the device according to the present invention, if the control device, or actuator, of the present invention has been connected with wrong polarity, or reversed polarity.

(38) In the upper diagram, the curves are plotted over time of the current through the control device, or actuator, and through the freewheeling diode. The solid line here indicates the current curve through the control device, or actuator. The dashed line indicates the current curve through the freewheeling diode.

(39) In the lower diagram, the curves are plotted over time of the voltage measured at the separate energy source, for example an EMV capacitor, at the second switch (HS), or high-side switch, as well as the voltage curve required for the controlling only of the second switch (HS), or high-side switch, as well as the voltage curve measured at the third switch (LS), or low-side switch. The thick solid line here indicates the voltage curve at the separate energy source, e.g. an EMV capacitor, and the dashed line indicates the voltage curve at the second switch (HS), or high-side switch, and the dot-dash line indicates the voltage curve for controlling only the second switch (HS), or high-side switch, by a processing device (C). The thin solid line indicates the voltage curve measured at the third switch (LS), or low-side switch.

(40) It can be seen clearly that at time t1 of the application of a voltage, a rise in voltage takes place in the voltage curve at the high-side switch (HS). At the same time, a rise in voltage in the voltage curve at the low-side switch (LS) takes place with the same speed, or substantially the same speed. At the same time, it can be seen that a current begins to flow through the freewheeling diode. The current through the control device, or actuator, does not have any significant value. From this it can be inferred that the control device, or actuator, is not usable.

(41) FIG. 6b shows an enlarged segment around the region around times t1 and t2. Here, the rises in voltage in the voltage curves at the high-side switch (HS) and low-side switch (LS) can be seen still more clearly.

(42) In FIG. 6b, it can be seen clearly that the rise in voltage at the low-side switch (LS) and at the high-side switch (HS) take place equally quickly, or substantially equally quickly. Accordingly, the actuator is not ready for use, because the current can flow through the freewheeling diode of the actuator.

(43) FIG. 7 shows a schematic diagram of an alternative specific embodiment of a device 700 according to the present invention that has been connected with correct polarity.

(44) Reference character 705 designates an energy reserve (ER), reference character 710 designates a first switch, or safety switch (SVS), reference character 715 designates a further switch for a further optional energy source, reference character 720 designates a further optional energy source, reference character 725 designates a capacitor for realizing an EMV compatibility of device 700, a so-called EMV capacitor, reference character 730 designates a second switch or high-side switch, reference character 731 designates a capacitor of the high-side switch, reference character 740 designates an actuator, reference character 741 designates a coil of the actuator, reference character 742 designates a freewheeling diode of the actuator, reference character 751 designates a capacitor of the low-side switch, reference character 750 designates a third switch or low-side switch, reference character 755 designates a ground potential, and reference character 760 designates an assembly having at least one microcontroller (C) and a safety controller (SCON), as well as the required external circuitry.

(45) Although the capacitors of high-side switch 731 and of low-side switch 751 are shown separately, the capacitors can be part of the respective switch, or part of device 700, if switches 730, 750, or device 700, are for example fashioned as integrated circuits (ASIC).

(46) Assembly 760 is fashioned to control first switch or safety switch (SVS) 710, further switch 715 for a further optional energy source 720, high-side switch 730, and low-side switch 750.

(47) In the alternative specific embodiment of device 700 according to the present invention according to FIG. 7, the separate energy source has been realized via a further optional energy source 715. In order to carry out the method according to the present invention, energy is provided or voltage is applied to actuator 740 by assembly 760, i.e. by the microcontroller (C) or by the safety controller (SCON), via switch 715.

(48) The voltage curve can then be acquired at the capacitors of high-side switch 731 and low-side switch 751.

(49) In a specific embodiment that is not explicitly shown of the device according to the present invention, the separate energy source is realized exclusively by the capacitor for EMV compatibility 370, 725. In such a specific embodiment, the device according to the present invention does not have an optional further energy source 330, 720, and also does not have a switch for optional further energy source 715.

(50) The controlling for the switchable elements safety switch (SVS), high-side switch (HS), and low-side switch (LS), as well as for optional further energy reserve 720, can take place both through the microcontroller (C), with the aid of software, i.e. a suitable program stored on a suitable data carrier, as well as in a completely hardware-controlled manner using suitable hardware logic, for example using the safety controller (SCON), a second (safety) microcontroller, FPGA, PAL, GAL, etc.

(51) A mixed controlling is also possible. Here, the microcontroller (C) controls for example safety switch (SVS) 710 and optional further energy reserve 330, 720 using software. High-side switch (HS) 320, 730 and low-side switch (LS) 340, 750 are controlled via a separate hardware path, for example via the safety controller (SCON).

(52) FIG. 8 shows a flow diagram of the method according to the present invention.

(53) In step 810, a voltage is applied to control device 360, 740.

(54) In step 820, a voltage curve or current curve is acquired at control device 360, 740, for example through the acquisition of a voltage curve at high-side switch (HS) 320, 730 and at low-side switch 340, 750.

(55) In step 830 a usability of control device 360, 740 is recognized as a function of the acquired voltage curve or current curve. For example, through the course of the voltage curve, in particular a rise in voltage at high-side switch (HS) 320, 730 that takes place more quickly than a voltage curve, in particular a rise in voltage, at low-side switch (LS) 340, 750, it can be recognized that control device 360, 740 has been installed or put into place with the correct polarity and is therefore usable.

(56) If the method according to the present invention yields the result that the control device, or actuator, is not usable, then the method can be multiply repeated up to error qualification. In the present context, an error qualification can be understood as meaning that an error entry is made to an error storage device, or a warning lamp is controlled in order to signal to the driver that the safety devices in the vehicle are not completely usable.