JP4281282B2 - Rudder angle sensor and control unit and their system - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control system that performs control based on an output value from a sensor, and more particularly to a control system that can avoid inconvenience when the sensor and / or the control unit is replaced.
[0002]
[Prior art]
Conventionally, in the case of a system that detects the steering angle of a steering wheel and controls the behavior of the vehicle (vehicle stability) using the detected value or parallel parking, the trajectory of the vehicle is calculated from the steering angle of the steering wheel, There is a system for instructing the user of an appropriate amount of handle operation. In such a system, the steering angle sensor detects that the steering angle at the neutral position detected by the steering angle sensor does not necessarily correspond to the steering angle when the vehicle is traveling straight (hereinafter referred to as “zero steering angle value”). Is corrected using the zero steering angle value, and control is performed using the corrected steering angle (hereinafter referred to as “absolute steering angle”).
[0003]
FIG. 4 is a diagram showing a conventional system 10 ′ using the steering angle sensor 12. This system 10 'is configured by a steering angle sensor 12, an electronic control unit 14 (hereinafter referred to as ECU 14), and a bus 16' for connecting them. The CPU 141 of the ECU 14 determines the straight traveling state of the vehicle (hereinafter referred to as “zero point”) based on the detected value from the vehicle speed sensor 20 or the like, and determines the steering angle value of the steering angle sensor 12 when traveling straight. Is stored in the storage unit 142 as a zero-point steering angle value. The rudder angle sensor 12 sends the detected rudder angle value to the ECU 14 via the bus 16 ′, and the CPU 141 of the ECU 14 corrects the rudder angle value using the zero point rudder angle value of the storage unit 142 to derive the absolute rudder angle. is doing.
[0004]
In this conventional system, when the rudder angle sensor 12 is replaced, the ECU 14 is discontinuous (in order to prevent various controls using the zero-point rudder angle value for the rudder angle sensor 12 before replacement). (Invalid) signal is sent to the ECU 14 from the steering angle sensor 12 after replacement via the bus 16 ', and the ECU 14 reacts to the discontinuity signal to determine the zero point again, and to the replaced steering angle sensor 12 The corresponding new zero-point steering angle value is stored in the storage unit 142, and an operation of sending a trigger signal for turning off the discontinuity signal to the steering angle sensor 12 via the bus 16 ′ has been realized. .
[0005]
[Problems to be solved by the invention]
However, since the discontinuity signal is not transmitted from the steering angle sensor 12 when the ECU 14 itself is replaced, the replaced ECU 14 is transferred to another steering angle sensor 12 already stored in the storage unit 142 of the ECU 14. Various controls may be performed using the corresponding zero steering angle value.
[0006]
On the other hand, the ECU 14 itself may be configured to determine the zero point periodically (e.g., every time the ignition switch is turned ON). There is a problem that various controls cannot be performed until the rudder angle value is determined.
[0007]
Further, as shown in FIG. 4, when the ECU 14 itself is replaced, the stored value 121 of the rudder angle sensor 12 is erased (when the stored value 121 does not exist in the stored value 121 of the rudder angle sensor 12, By connecting the power supply line 123 ′ to the steering angle sensor 12 via the ECU 14, the power of the steering angle sensor 12 is surely turned off when the ECU 14 is replaced. In such a case, the ECU 14 is connected to the power supply line 123 ′ that is essentially unnecessary for the ECU 14, so that an essentially unnecessary space and connection for securing a wiring path for connection are available. There was a problem that a connector for use was required.
[0008]
Therefore, the present invention provides a steering angle sensor, a control unit, and these that can reliably avoid inconveniences that may occur due to replacement of all possible modes of the steering angle sensor and ECU without using the power supply line as described above. The purpose is to provide a system.
[0009]
[Means for Solving the Problems]
The object is to provide a steering angle sensor and a control unit including a determining unit for determining a zero-point steering angle value corresponding to a straight ahead of the vehicle from the steering angle values output by the steering angle sensor. A control system comprising:
First storage means of the rudder angle sensor in which a first identification symbol is stored;
Second storage means of the control unit in which a second identification symbol is stored;
It said control unit or the steering angle sensor includes a first identification symbol stored in the first storage means of the upper Kikajikaku sensor, a second identification code is stored in the second storage means of the control unit And is configured to match
The control unit is configured to determine the effectiveness of the steering angle value based on the verification result,
Each of the first and second identification symbols is achieved by a control system, characterized in that it is substantially the same as the zero steering angle value determined by the determining means .
[0018]
According to the said invention, the effectiveness with respect to the steering angle sensor of the zero point steering angle value which the control unit determined can be determined reliably by collation of the identification symbol of a steering angle sensor and a control unit. Specifically, when the control unit and / or the rudder angle sensor are replaced, the identification symbol on the rudder angle sensor side and the identification symbol on the control unit side become inconsistent. An abnormality in the correspondence relationship is reliably detected. In such a case, if the control unit determines the zero-point rudder angle value again, the rudder angle value from the rudder angle sensor can be validated for the control unit, and erroneous control can be reliably prevented. Can do. The verification of the identification symbol may be executed on either the control unit side or the steering angle sensor side.
[0019]
Further, the upper Symbol identification symbol, is substantially the same as the zero point steering angle value above, even if the control unit and / or the steering angle sensor is replaced, even if the identification mark is coincidental, control There is no false control by the unit.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram of a system 10 of the present invention that illustratively uses a steering angle sensor 12. The system 10 according to the present invention can also be applied to sensors other than the steering angle sensor 12 and ECUs.
[0027]
As shown in FIG. 1, the system 10 determines a straight traveling time of the vehicle from a steering angle sensor 12 that detects a steering angle of a steering wheel (not shown) and information such as a vehicle speed and a yaw rate, and an absolute steering angle. ECU 14 that performs various controls based on the above, and a bus (data transmission path) 16 that connects at least the steering angle sensor 12 and the ECU 14 and enables bidirectional communication at least between the steering angle sensor 12 and the ECU 14. Composed.
[0028]
The rudder angle sensor 12 includes a data processing CPU 121 and a volatile sensor storage unit 122 such as a volatile RAM that is backed up by a battery or the like (a property that data disappears when the power is turned off). For this purpose, a power supply line 123 is connected to the rudder angle sensor 12 so that the sensor storage unit 122 stores the stored data unless the power supply is stopped due to replacement of the rudder angle sensor 12 or the like. Can be held. Note that the power supply line 123 is not connected to the ECU 14 unlike the above-described conventional example.
[0029]
The bus 16 includes a transmission path capable of bidirectional communication such as a CAN (Controller Area Network) bus, a bidirectional asynchronous communication circuit such as a UART (Universal Asynchronous Receiver Transmitter), and the like.
[0030]
The ECU 14 includes a CPU 141 and an ECU storage unit 142. The CPU 141 determines the behavior of the vehicle from detection values from various sensors, and determines the steering angle value of the steering angle sensor 12 when the vehicle is traveling straight ahead as the zero steering angle. The value is stored in the storage unit 142 of the ECU 14 as a value. For example, the CPU 141 uses the vehicle speed value from the vehicle speed sensor 20, the rudder angle value from the rudder angle sensor 12, and the yaw rate value from the yaw rate sensor (not shown), and the vehicle speed is equal to or greater than a predetermined amount and the absolute value of the yaw rate. Is learned as a zero point. The CPU 141 calculates an absolute steering angle from the steering angle value of the steering angle sensor 12 based on the zero-point steering angle value stored in the ECU storage unit 142, and is connected to the ECU 14 using the absolute steering angle. Various control contents for an output device (for example, an actuator for braking a wheel) are determined. These output devices may be connected to the ECU 14 via the bus 16.
[0031]
The ECU storage unit 142 of the ECU 14 includes a nonvolatile memory such as an EEPROM (electrically erasable programmable ROM). Therefore, unlike the sensor storage unit 122 of the steering angle sensor 12, the ECU storage unit 142 of the ECU 14 does not require power supply like the power supply line 123. In addition, the ECU 14 can execute various controls using data stored in the nonvolatile ECU storage unit 142 at the same time when the ignition switch is turned on (a state in which current flows through the ignition coil). it can.
[0032]
The system 10 of the first embodiment according to the present invention has a unique identification symbol for the steering angle sensor 12 and the ECU 14 to recognize each other in order to detect a mismatch when the steering angle sensor 12 and / or the ECU 14 are replaced. Is used.
[0033]
FIG. 2 is a flowchart showing the operation of the system of the first embodiment according to the present invention. When the ignition switch is turned on, in step 100, the ECU 14 determines whether or not an initial setting has already been made. Specifically, the ECU 14 determines whether or not the ECU storage unit 142 has a stored value.
[0034]
If the initial setting has not been made yet, the process proceeds to step 102 where the ECU 14 learns the zero point, stores the zero point steering angle value as a stored value in the ECU storage unit 142, and stores the zero point steering angle value in the steering angle sensor 12. The identification symbol of the ECU 14 is sent via the bus 16. At this time, the rudder angle sensor 12 stores the transmitted identification symbol as its own identification symbol in the sensor storage unit 122 and proceeds to step 108.
[0035]
If the initial setting has already been made, the process proceeds to step 104 where the ECU 14 collates the identification symbol of the ECU 14 with the identification symbol of the steering angle sensor 12. Specifically, the ECU 14 sends its identification symbol to the rudder angle sensor 12 via the bus 16, and the CPU 121 of the rudder angle sensor 12 sends the identification symbol sent from the ECU side to the rudder angle sensor 12. The identification symbol stored in the sensor storage unit 122 is compared, and the result is sent to the ECU 14 via the bus 16. Or ECU14 may compare and collate the identification symbol of the steering angle sensor 12 sent from the sensor side, and its own identification symbol.
[0036]
If the two identification symbols do not match as a result of the verification of the identification symbols, the process proceeds to step 106, where the ECU 14 learns the zero again, stores the new zero-point steering angle value in the ECU storage unit 142, and the steering angle sensor. 12, a signal for requesting updating of the identification symbol of the steering angle sensor 12 is sent via the bus 16 together with the identification symbol of the ECU 14. In response to this signal, the steering angle sensor 12 updates the transmitted identification symbol as its own new identification symbol, and proceeds to step 108.
[0037]
In step 108, the ECU 14 derives the absolute steering angle corresponding to the steering angle value transmitted by the steering angle sensor 12 in response to the request signal, using the zero-point steering angle value of the ECU storage unit 142, as usual. Various controls are performed based on the absolute steering angle.
[0038]
Thus, according to the system 10 of the first embodiment, even when a mismatch occurs between the ECU 14 and the steering angle sensor 12, the mismatch can be reliably detected. Later, since the zero point is learned again, the consistency between the ECU 14 and the steering angle sensor 12 can be ensured. Further, when the inconsistency does not occur, the ECU 14 can quickly shift to the normal control state by using the zero point steering angle value stored in the ECU storage unit 142.
[0039]
For example, if only the rudder angle sensor 12 is replaced, inconsistency is detected at step 104. When only the ECU 14 is replaced and the replaced ECU 14 does not have a stored value (when replaced with a new ECU), the replaced ECU 14 stores the stored value in step 100. If it is replaced (if it is replaced with an ECU used elsewhere), inconsistency is detected at step 104. Further, when both the rudder angle sensor 12 and the ECU 14 are exchanged, the mismatch is detected in the same manner in step 100 or step 104.
[0040]
In the system 10 of the first embodiment, the unique identification symbols for mutual recognition used by the steering angle sensor 12 and the ECU 14 are serial numbers at the time of manufacture of the ECU 14, serial numbers given at the time of factory shipment, random numbers, and the like. However, the zero-point steering angle value that the ECU 14 learns is most preferable. In this case, even if the identification symbol of the exchanged rudder angle sensor 12 (even if the ECU 14 or both of them are exchanged) coincides with the identification symbol of the rudder angle sensor 12 before the exchange accidentally, the ECU 14 Can still effectively use the zero steering angle value stored as the identification symbol. That is, it is not detected that there has been a replacement in Step 100 and Step 102 described above, but the fact that the zero-point steering angle values for the respective steering angle sensors 12 before and after the replacement match in the system 10 after the replacement. This means that the zero steering angle value is still valid, so there is virtually no mismatch and therefore no inconveniences will occur.
[0041]
The system 10 of the second embodiment according to the present invention prevents inconvenience when the rudder angle sensor 12 and / or the ECU 14 is replaced without using the unique identification symbol as described above.
[0042]
FIG. 3 is a flowchart showing the operation of the system of the second embodiment according to the present invention. When the ignition switch is turned on, in step 200, the ECU 14 determines whether or not a replacement completion flag is set in the ECU storage unit 142.
[0043]
When the replacement completion flag is not set, the process proceeds to step 210, where the ECU 14 learns the zero point as described above, and sends the zero point steering angle value to the steering angle sensor 12 via the bus 16. In step 212, the steering angle sensor 12 resets the zero steering angle value to 0 in order to replace the output steering angle value with the absolute steering angle, and notifies the ECU 14 that the replacement with the absolute steering angle value has been completed. This is done via the bus 16. Thereafter, the rudder angle sensor 12 communicates with the ECU 14 by an absolute rudder angle.
[0044]
In step 214, the ECU 14 receives a notification from the steering angle sensor 12, sets a replacement completion flag in the ECU storage unit 142, and proceeds to step 208.
[0045]
In step 202, the ECU 14 determines whether or not a discontinuity signal is sent from the steering angle sensor 12. For this purpose, the rudder angle sensor 12 of the present embodiment is used when the stored value of the sensor storage unit 122 of the rudder angle sensor 12 is erased (therefore, the rudder angle value to be output is not an absolute rudder angle). ), And is configured to generate a discontinuous signal. In other words, the discontinuous signal is generated when the power is first turned on in the sensor storage unit 122 of the steering angle sensor 12.
[0046]
If the discontinuous signal is sent, the ECU 14 learns the zero point as described above in step 204, and causes the steering angle sensor 12 to set the zero point steering angle value to the bus 16 together with a trigger signal for canceling the discontinuous signal. Send through. In step 206, the steering angle sensor 12 resets the transmitted zero steering angle value to 0, cancels the discontinuity signal, and proceeds to step 208. Thereafter, the steering angle sensor 12 communicates with the ECU 14 by the absolute steering angle because the zero-point steering angle value is reset to zero.
[0047]
In step 208, the ECU 14 performs various controls based on the absolute steering angle that the steering angle sensor 12 transmits in response to the request signal, as usual. Therefore, the ECU 14 of the system 10 of the second embodiment uses the absolute steering angle sent from the steering angle sensor 12 without calculating the absolute steering angle itself.
[0048]
Thus, according to the system 10 of the second embodiment, even if the rudder angle sensor 12 is replaced, the mismatch can be reliably detected by the step 202, and after the detection, the zero point is again detected. Therefore, the consistency between the ECU 14 and the steering angle sensor 12 can be ensured.
[0049]
Further, when the ECU 14 is replaced, the replacement completion flag is not set, so that the replacement can be reliably detected at step 200. Furthermore, even if the replacement completion flag remains in the ECU storage unit 142 of the ECU 14 after replacement, the replacement ECU 14 must not detect the detected value from the steering angle sensor 12 because the replacement completion flag is set. Although used as a rudder angle, the absolute rudder angle itself is still effective in the system 10, so that no inconvenience occurs.
[0050]
The “first storage means of the steering angle sensor” and the “second storage means of the control unit” described in the claims are the “sensor storage unit 122”, “ECU” described in the detailed description of the invention. Each corresponds to the storage unit 142 " .
[0051]
As mentioned above, although the preferable Example of this invention was explained in full detail, it is clear that this invention is not limited to the Example mentioned above. For example, in the system of the first embodiment, the sensor storage unit 122 of the steering angle sensor 12 may be a non-volatile memory instead of a volatile memory. This is based on the fact that the ECU 14 of the first embodiment does not require a discontinuous signal from the steering angle sensor 12 as in the conventional system and can determine inconsistencies. Therefore, the steering angle sensor 12 does not need to be constantly supplied with power by the power supply line 123, and may be configured to be supplied with power from when the ignition switch is turned on.
[0052]
In the system of the first embodiment, the ECU 14 is configured to set its own identification symbol in the steering angle sensor 12, but the ECU 14 uses the identification symbol of the steering angle sensor 12 as its own identification symbol. May be stored in the ECU storage unit 142. In such a case, the ECU 14 collates the identification symbol sent from the sensor side with the identification symbol stored in the ECU storage unit 142. If the identification symbol does not match, the ECU 14 learns the zero point again, together with the new zero point steering angle value. A new identification symbol is stored in the ECU storage unit 142. In the system 10 of this embodiment, if the steering angle sensor 12 transmits its own identification symbol to the ECU 14 when the ignition switch is turned on, the bus 16 is connected to the ECU 14 from the steering angle sensor 12. It may be a unidirectional transmission path capable of serial communication.
[0053]
In addition, although the above-described embodiments have been described with respect to a system using the rudder angle sensor 12, the system of the present invention can be applied to a system using a sensor other than the rudder angle sensor 12. is there. For example, in a versatile system using a sensor, when executing a process for compensating for the temperature nonlinearity inherent in the sensor, the processing side executes a compensation program for the sensor, but the sensor or the like is replaced. In such a case, since a compensation program for different sensors is used, inappropriate processing is executed. The system of the present invention can also be applied to avoid such inconvenience.
[0054]
Moreover, although the Example mentioned above was a system for ensuring the consistency between one sensor and ECU, it is applied also to the system for ensuring the consistency between several sensors and ECU. Of course, it is possible.
[0055]
【The invention's effect】
Since the present invention is as described above, the following effects can be obtained. According to the first aspect of the present invention, inconvenience that may occur due to replacement of all possible modes of the steering angle sensor and the control unit can be reliably avoided by using the identification symbol, and unnecessary power supply can be performed. Unnecessary cost and weight can be reduced by eliminating wires. Further, since the zero-point rudder angle value is used as the identification symbol, the control of the control unit is not affected even if the identification code coincides accidentally at the time of collation after replacement.
[Brief description of the drawings]
FIG. 1 is a block diagram of a system 10 of the present invention that illustratively uses a steering angle sensor 12;
FIG. 2 is a flowchart showing the operation of the system of the first embodiment according to the present invention.
FIG. 3 is a flowchart showing the operation of the system of the second embodiment according to the present invention.
FIG. 4 is a diagram showing a conventional system using a steering angle sensor.
[Explanation of symbols]
12 Rudder angle sensor 121 Sensor side CPU
122 Sensor side storage unit 123 Power supply line 14 Electronic control unit 141 Electronic control unit side CPU
142 Electronic Control Unit Side Storage Unit 16 Bus 20 Vehicle Speed Sensor

Claims (2)

A control system including a rudder angle sensor and a control unit including a determining unit for determining a zero point rudder angle value corresponding to when the vehicle goes straight from the rudder angle value output by the rudder angle sensor,
First storage means of the rudder angle sensor in which a first identification symbol is stored;
Second storage means of the control unit in which a second identification symbol is stored;
It said control unit or the steering angle sensor includes a first identification symbol stored in the first storage means of the upper Kikajikaku sensor, a second identification code is stored in the second storage means of the control unit And is configured to match
The control unit is configured to determine the effectiveness of the steering angle value based on the verification result,
Each of said 1st and 2nd identification symbol is substantially the same as the zero steering angle value determined by the said determination means , The control system characterized by the above-mentioned . When the first identification symbol stored in the first storage means of the rudder angle sensor does not match the second identification symbol stored in the second storage means of the control unit, the control unit 2. The control system according to claim 1, wherein the zero point rudder angle value is re-determined, and the respective identification symbols in the first and second storage means are updated based on the re-determined zero point rudder angle value.

Images