JPH0835860A - Sensor controller - Google Patents

Abstract

PURPOSE:To obtain a sensor controller which can stably control an object to be controlled without giving adverse influences to A/D-converted values and can surely cope with insufficient contact of the contacting section between a sensor and controller without using expensive contacting section plated with gold, etc. CONSTITUTION:A sensor 2 which outputs detecting signals D, controller 1 which controls an object 3 to be controlled by A/D-converting the detecting signals D, signal line LD which connects the output terminal (b) of the sensor 2 to the input terminal (e) of the controller 1, power line LP, and grounding line LG are provided. The controller 1 incorporates a short-circuiting means 13 which short-circuits the input terminal (e) to either a power source or ground at prescribed timing and the means 13 destroys an oxide film which increases the contact resistance of the signal line LD by making a prescribed electric current to flow between the output terminal (b) and input terminal (e) respectively connected to both ends of the signal line LD by applying a prescribed voltage across the terminals (b) and (e) through the power line LP or grounding line LG.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sensor control device such as a torque sensor used in, for example, a power steering device of an automobile, and particularly to a defective contact of a connector part between the sensor part and the control part without increasing cost. The present invention relates to a sensor control device that reliably prevents or detects the above and improves reliability.

[0002]

2. Description of the Related Art Conventionally, in steering devices for automobiles and the like, power steering control devices have been developed in which steering torque is assisted by an electric motor. In this type of device, a torque sensor is used as the sensor means, but various proposals have been made to ensure reliability.

As a conventional sensor control device, for example, there is an electric power steering protection device described in JP-A-64-44378. In this case, the torque sensor composed of the variable resistor is connected to the controller via the connector, and the detection signal from the torque sensor is input to the AD converter in the controller.

Further, an adjusting resistor for detecting a poor contact with the torque sensor is provided in the controller so that an abnormality such as a poor contact with the torque sensor via the connector can be quickly detected. ing. Generally, gold plating is often used for connector pins of signal lines used for connecting a controller to a torque sensor or the like in order to prevent contact failure.

The reason for the poor contact through the connector is that the shavings generated by rubbing between the connector pins to be connected and the connector pin are oxidized after being accumulated between the contact surfaces of the connector pins. It occurs because the electrical conductivity decreases (becomes a resistor), and as a countermeasure for such contact failure, it is usually considered that the connector pin is plated with a noble metal (for example, gold) that is difficult to oxidize. Is.

FIG. 20 is a circuit diagram schematically showing an example of a conventional sensor control device. In the figure, 1 is, for example, a control device for electric power steering, 2 is a torque sensor composed of a variable resistor RS, a is a power supply input terminal of the torque sensor 2 (hereinafter referred to as power supply terminal), and b is an output of the torque sensor 2. A terminal, c is a ground terminal of the torque sensor 2, d is a power output terminal (hereinafter, referred to as a power terminal) of the controller 1, e is an input terminal of the controller 1, and f is a ground terminal of the controller 1.

LP is a power supply line connecting between the power supply terminal a of the torque sensor 2 and the power supply terminal d of the control device 1, and LD is between the output terminal b of the torque sensor 2 and the input terminal e of the control device 1. A signal line, LG, which is connected, is a ground line which connects the ground terminal c of the torque sensor 2 and the ground terminal f of the control device 1.

The torque sensor 2 picks up the current flowing from the power supply terminal a to the ground terminal c as a divided voltage of the variable resistor RS and detects a steering signal D applied to a steering system (not shown). Is output.

The control device 1 controls an electric motor (not shown) connected to the steering system according to the detection signal D from the torque sensor 2, so that an AD converter (not shown) is provided.
, A microcomputer 10 having an AD conversion port TS, a sensor detection circuit 12 for waveform-shaping the detection signal D, a sensor power supply circuit and a motor drive circuit (both not shown).

The sensor detection circuit 12 inputs the detection signal D after waveform shaping to the microcomputer 10, and the microcomputer 10 AD-converts and processes the detection signal D. The sensor detection circuit 12 uses the signal line LD to which the detection signal D is input.
1 has a resistor RM for detecting disconnection and a filter including a resistor R and a capacitor C.

The resistor RM has an input terminal e connected to the signal line LD and a ground terminal f connected to the ground line LG.
When the signal line LD between the output terminal b and the input terminal e is disconnected, the voltage input to the AD conversion port TS of the microcomputer 10 is set to the ground level.

Usually, the detection accuracy of the torque sensor 2 is inversely proportional to the current flowing through the signal line LD. For example, the smaller the current flowing through the signal line LD, the smaller the voltage drop, and the higher the detection accuracy of the torque sensor 2. Therefore, conventionally, the sensor control device as shown in FIG. 20 is designed to reduce the current flowing through the signal line LD in order to improve the detection accuracy as a sensor.

For example, the resistor RM for detecting the disconnection is connected in parallel to the variable resistor RS in the torque sensor 2, so that if the resistance value is small, the current flowing through the signal line LD increases, and the sensor resistance. The detection accuracy will be reduced. Therefore, as the resistor RM, the variable resistor RS
A resistor having a resistance value of several hundred times or more, and several μA to several 1 from the output terminal b of the torque sensor 2 to the signal line LD.
Only a current of about 0 μA flows out.

By the way, it is known that the oxide film resulting from the oxidation of the shavings of the connector pin described above is destroyed when a current of a predetermined value (about several mA) or more is applied, and the power supply terminals a and d and the ground terminal. Regarding c and f, the contact resistance value is returned to the original value by the usual energization of several mA or more, so that no contact failure or the like occurs.

However, the input / output terminals b at both ends of the signal line LD
With respect to and e, for the reason of ensuring the detection accuracy described above, the sensor detection circuit 12 connects the signal line LD to several μA to several tens of μA via the resistor RM having a large resistance value (about 1 MΩ).
Only a certain amount of current is flowing. Therefore, the normal detection current cannot destroy the oxide film generated in the connector pin, and the contact failure of the connector portion including both ends of the signal line LD becomes a serious problem. Therefore, it is required to cancel, prevent, or detect the contact failure around the signal line LD.

[0016]

As described above, the conventional sensor control device cannot remove the contact failure generated on the contact surface of each connector pin that connects the control device 1 and the sensor 2, and therefore the contact of the connector pin cannot be eliminated. As a countermeasure against defects, since the connector pins are plated with a noble metal that is difficult to oxidize, for example, the connection point between the sensor 2 and the harness (not shown), the connection point between the harness and the control device 1, etc. As the number increases, the connection circuit becomes expensive.

The present invention has been made in order to solve the above-mentioned problems, and it is a measure against a reliable contact failure of the connection circuit section between the sensor section and the control section without applying gold plating or the like which causes an increase in cost. It is also an object of the present invention to realize a sensor control device by improving the safety and reliability of the system by making a failure determination.

[0018]

According to a first aspect of the present invention, there is provided a sensor control device which outputs a detection signal related to an object to be controlled, and A which converts the detection signal into a digital signal.
A control device that includes a D converter and controls a control target using an AD-converted detection signal, a signal line that connects an output terminal of the sensor and an input terminal of the control device, and a power supply terminal of the sensor and control A power line connecting between the power terminal of the device and
The control device includes a ground wire that connects between the ground terminal of the sensor and the ground terminal of the control device, and the control device includes short-circuiting means for short-circuiting the input terminal of the control device to one of the power supply and the ground at a predetermined timing. Is a device for applying a predetermined voltage between an output terminal and an input terminal connected to both ends of a signal line via a power supply line or a ground line to supply a predetermined current.

According to a second aspect of the present invention, there is provided the sensor control device according to the first aspect, wherein the short-circuit means comprises an opening / closing element having one end connected to the input terminal and the other end grounded. It includes an opening / closing element drive unit for closing and driving the opening / closing element at a predetermined timing.

The sensor control device according to a third aspect of the present invention is the sensor control device according to the first aspect, wherein the short-circuit means comprises an opening / closing element having one end connected to the input terminal and the other end connected to the power supply. Includes an opening / closing element drive unit for closing and driving the opening / closing element at a predetermined timing.

Further, according to a fourth aspect of the present invention, in the sensor control device according to the second or third aspect, the short-circuit means includes a limiting resistor that limits a current flowing through the switching element.

According to a fifth aspect of the present invention, in the sensor control device according to any one of the first to fourth aspects, the predetermined timing is set when the AD converter is not operating.

According to a sixth aspect of the present invention, in the sensor control device according to any one of the first to fourth aspects, the predetermined timing is when the control device is not driving the controlled object. is there.

According to a seventh aspect of the present invention, in the sensor control device according to any one of the first to sixth aspects, the control device turns on the AD converter after a predetermined time has elapsed since the short-circuit means was opened. It includes a timer means for enabling.

The sensor control device according to an eighth aspect of the present invention is the sensor control device according to any one of the first to seventh aspects, wherein the control device performs AD conversion during opening of the short-circuit means at the time of starting the control device. A sensor resistance value calculating means for calculating a resistance value of the sensor from the detected signal and the detection signal AD-converted during the short circuit of the short-circuiting means; and a sensor failure determining means for determining a sensor failure based on the resistance value. And a control stop means for stopping the control of the control target when the sensor is determined to be defective.

Further, a sensor control device according to a ninth aspect of the present invention is the sensor control device according to any one of the first to eighth aspects, wherein the control device is the detection signal AD-converted while the short circuit means is open and the short circuit means. Contact resistance value calculating means for calculating the contact resistance value of the connector part including both ends of the signal line from the detection signal AD-converted during the short circuit of the connector part, and the connector part for determining the defect of the connector part based on the contact resistance value. Defect determination means,
The control unit includes a control stopping unit that stops the control of the control target when the defect of the connector is determined.

According to a tenth aspect of the present invention, in the sensor control device according to any one of the first to ninth aspects, the control device opens the detection signal when the short-circuit means is short-circuited. It includes a detection signal holding unit that holds the detected signal until it is held.

A sensor control device according to an eleventh aspect of the present invention is the sensor control device according to any one of the first to tenth aspects, in which a plurality of sensors are arranged in parallel, and the control device is an AD converter of the plurality of sensors. The short-circuiting means associated with the non-operated sensor is sequentially opened and closed.

[0029]

According to the first aspect of the present invention, a predetermined voltage is applied to the signal line through the power supply line or the ground line at a predetermined timing when the controlled object is not controlled using the AD conversion value, and a predetermined current is supplied. Then, a sufficient current is supplied to destroy the oxide film that causes an increase in the contact resistance of the signal line to prevent the occurrence of contact failure.

According to a second aspect of the present invention, a switching element having one end connected to the input terminal of the control device and the other end grounded is inserted as a short-circuiting means, and the switching element is closed in response to a predetermined timing. The oxide film is destroyed by a current flowing through the switching element via the power supply line and the signal line.

Further, according to a third aspect of the present invention, an opening / closing element having one end connected to the input terminal of the control device and the other end connected to the power source is inserted as a short-circuit means, and the opening / closing element is responsive to a predetermined timing. The oxide film is destroyed by the current flowing from the switching element through the signal line and the ground line.

Further, according to the fourth aspect of the present invention, the current flowing through the switching element is limited by the limiting resistor to prevent the switching element and the transistor element forming the switching element driving section from being destroyed.

Further, in claim 5 of the present invention, A
When the D converter is not operating, the switching element is closed to destroy the oxide film, and noise generated when the switching element is driven and fluctuations in the detection signal are not influenced by the control.

Further, according to a sixth aspect of the present invention, when the controlled object is not controlled, the switching element is closed to destroy the oxide film, and noise generated when the switching element is driven or fluctuation of the detection signal is controlled. Try not to affect.

Further, according to a seventh aspect of the present invention, the object to be controlled is controlled by using the AD conversion value after a lapse of a predetermined time (after stabilization) after stopping (opening) the short-circuiting means and driving the short-circuiting means. The noise generated at the time and the fluctuation of the detection signal are AD
Do not affect the converted value.

In the eighth aspect of the present invention, the AD conversion value when the short-circuit means is stopped (open) and the short-circuit means are short-circuit driven when the control device is activated (first energization). The resistance value of the sensor is calculated from the A / D converted value when the sensor resistance value changes, and if the sensor resistance value changes from the set value by a predetermined amount (for example, several percent or more), it is determined that the sensor is defective and the control is stopped, and safety Improve sex.

According to a ninth aspect of the present invention, the contact resistance value of the connector portion is calculated from the AD conversion value when the short-circuit means is open and the AD conversion value when the short-circuit drive is performed, and the contact resistance value is calculated. If the value changes by a predetermined amount (for example, several percent or more), it is determined that the connector is defective and control is stopped.
Improve safety.

In the tenth aspect of the present invention,
The detection signal when the short-circuit means is short-circuited is held until the short-circuit means is opened so that the detection signal does not change when the short-circuit means is driven. Accordingly, even if the detection signal is AD-converted immediately after the driving of the short-circuiting means, the control is not affected.

In the eleventh aspect of the present invention,
The current consumption is suppressed by sequentially opening and closing the short-circuit means associated with the sensor that is not AD converted.

[0040]

【Example】

Example 1. (Corresponding to Claims 1 to 6) Hereinafter, Embodiment 1 of the present invention will be described with reference to the drawings. FIG.
1 is a circuit configuration diagram showing a first embodiment of the present invention, and shows an electric power steering control device as an example similarly to the above. In the figure, 1, 2, 10, 12, a-
f, D, LP, LD, LG, and TS are the same as those described above, and in this case, the circuit configuration of the control device 1 and the functional configuration of the microcomputer 10 are different.

Reference numeral 3 denotes an electric motor (hereinafter, simply referred to as a motor) which is a control target of the control device 1. For example, the electric motor 3 is connected to a steering system (not shown) to assist the steering operation. There is. The motor 3 has input terminals i and j connected to drive output terminals g and h of the control device 1, and a detection signal D of the torque sensor 2
Controlled according to.

Variable resistor RS constituting the torque sensor 2
Has one end connected to the power supply terminal d of the control device 1 via the power supply terminal a and the power supply line LP, and the other end connected to the ground terminal f of the control device 1 via the ground terminal c and the ground line LG. The tap end is connected to the input terminal e of the control device 1 via the output terminal b and the signal line LD.

The control device 1 includes a microcomputer 10 and a sensor detection circuit 12, as well as a sensor power supply circuit 11 for supplying power to the torque sensor 2 and a motor drive circuit 14 for driving the motor 3. Further, in this case, the control device 1 includes a short circuit 13 that is controlled by the voltage level of the output port TP of the microcomputer 10 and applies a predetermined voltage to both ends of the signal line LD to energize it.

The terminals a to c of the torque sensor 2 are connected to the terminals d to f of the sensor detection circuit 12 in the control device 1, respectively. The terminals g and h of the motor drive circuit 14 in the control device 1 are connected to the terminals i and j of the electric motor 3, respectively. A harness is connected between the terminals a to j, and a connector pin is connected between the harness and the terminals a to j.

The sensor power supply circuit 11 is the sensor detection circuit 1
2, the power is supplied to the torque sensor 2 via the power supply terminal d and the power supply line LP, and the motor drive circuit 14 uses the microcomputer 1
The motor 3 is driven by a drive signal output from 0 through the drive output terminals g and h.

Further, the short circuit 13 is the sensor detection circuit 1
The input terminal e of 2 is short-circuited to the power supply or the ground, and a predetermined voltage is applied to both ends of the signal line LD connected to the input terminal e via the power supply line LP or the ground line LG, and a predetermined current is applied to the signal line LD. Is flowed, the oxide film of the connector portion including the input terminal b and the output terminal e is destroyed.

FIG. 2 is a circuit diagram showing a specific example (corresponding to claim 2) in the case where the short circuit 13 in FIG. 1 is short-circuited to the ground. In this case, the sensor power supply circuit 11 is not shown. And

In FIG. 2, RM, R and C have the same meanings as described above. The resistor RM for detecting disconnection in the sensor detection circuit 12 is connected between the input terminal e and the ground terminal f, and is set to, for example, 1 MΩ so as not to adversely affect the detection signal D from the torque sensor 2. It has a large resistance value.

The short circuit 13 is composed of a current adjusting resistor RB connected to the input terminal e and an NPN transistor TRN having a collector connected to the resistor RB. The resistor RB limits the current flowing through the NPN transistor TRN and prevents overcurrent breakdown of the NPN transistor TRN. Also, the NPN transistor TRN
Has its emitter grounded and its base connected to the output port TP of the microcomputer 10.
It is designed to be driven and controlled by.

The power supply terminal a of the torque sensor 2 is connected to the power supply terminal d of the sensor detection circuit 12, and further connected to the sensor power supply circuit 11 via the sensor detection circuit 12 to function as a sensor power supply. The ground terminal c of the torque sensor 2 is connected to the ground terminal f of the sensor detection circuit 12, and is also grounded via the sensor detection circuit 12. Further, the output terminal b of the torque sensor 2 is connected to the input terminal e of the sensor detection circuit 12, and further, through the filter composed of the resistor R and the capacitor C in the sensor detection circuit 12, the AD conversion port of the microcomputer 10. It is connected to the TS.

In this case, the short circuit 13 in the control unit 1
When the microcomputer 10 does not control the motor 3 based on the AD conversion value (that is, the AD converter is not operating or the motor 3 is not driving), the input terminal e is supplied with power or ground. And a predetermined voltage is applied to the input / output terminals b and e connected to both ends of the signal line LD via the power supply line LP or the ground line LG to supply a predetermined current.

Therefore, as shown in FIG. 2, the short circuit 13 has an N terminal, one of which is connected to the input terminal e for inputting the detection signal D to the AD converter in the microcomputer 10 and the other of which is grounded.
It is composed of a PN transistor TRN (switching element).
Further, the microcomputer 10 in the control device 1 includes an opening / closing element drive unit (not shown) that drives the NPN transistor TRN.

Next, referring to the flow chart of FIG. 3 showing the processing routine of the microcomputer 10 together with FIG. 1 and FIG. 2, the short circuit 13 is connected to the signal line LD and the input terminal e.
The operation of the first embodiment of the present invention when the circuit is shorted to the ground (corresponding to claim 2) will be described. First, the microcomputer 10 determines whether a flag requesting AD conversion is set (step S1).

If it is determined that the flag is not set (that is, NO), it means that the motor 3 is not controlled based on the AD conversion value.
In order to execute the operation in the contact failure prevention mode, 0 sets the signal level of the output port TP to "H", turns on the NPN transistor TRN, and short-circuits the short circuit 13 (step S2).

As a result, the current adjusted by the current adjusting resistor RB in the short circuit 13 is supplied from the sensor power supply circuit 11 to the power supply terminal d of the sensor detection circuit 12, the power supply line LP, and the power supply terminal of the torque sensor 2. a, resistor RS in torque sensor 2, output terminal b of torque sensor 2, signal line L
D, input terminal e of the sensor detection circuit 12, resistors RB, N
The PN transistor TRN and the ground flow in this order.

At this time, since the sensor power supply circuit 11 applies a sufficient predetermined voltage to the current flowing from the sensor power supply circuit 11 toward the short circuit 13, the signal line LD
Even if there is an oxide film that causes a contact failure in the connector portion including the input / output terminals b and e at both ends of the, the oxide film can be destroyed and a good contact state can be maintained.

Note that the detection signal D is not input to the AD conversion port TS during the processing in the contact failure prevention mode, but since the AD converter in the microcomputer 10 is in the non-operating timing, no trouble occurs. There is no. Also,
At this time, the drive signal from the microcomputer 10 to the motor 3 indicates a non-operation state.

On the other hand, in step S1, the flag requesting AD conversion is set (that is, YE).
If it is determined to be S), the motor 3 can be controlled based on the AD conversion value. Therefore, the microcomputer 10 sets the output port TP to the “L” level in order to execute the operation in the normal control mode. The driving of the short circuit 13 is stopped (step S3).

Then, the value of the AD conversion port TS (the detection value of the torque sensor 2) is AD-converted (step S4).
Here, the AD-converted value is stored in the RAM in the microcomputer 10.
(Not shown). Then, the microcomputer 10
The output value for the motor 3 is determined based on the AD converted value of the torque sensor 2 stored in the RAM, the motor drive signal is output to the motor drive circuit 14, and the motor 3 is controlled (step S5).

Here, in step S1, A
The D conversion flag is determined, and when the AD converter is not operating, the predetermined voltage and the predetermined current are applied to the power supply line LP and the signal line LD, but the motor 3 is not driven. Sometimes, a predetermined current may be supplied.

Although FIG. 2 and FIG. 3 show the case where the short circuit 13 short-circuits the input terminal e to the ground in the contact failure prevention mode, the signal line LD and the input terminal e should be short-circuited to the power source. May be. In this case, the torque sensor 2 is connected via the signal line LD and the ground line LG.
A predetermined voltage is applied to the output terminal b of the.

FIG. 4 is a circuit configuration diagram showing a specific example (corresponding to claim 3) in the case where the short circuit 13 according to the first embodiment of the present invention is short-circuited to the power supply. 1, 2, 10, 12, 1
3, af, D, RS, RM, R, C, RB, LP, L
D and LG are the same as described above.

TRP is a PNP transistor whose collector is connected to the resistor RB for current adjustment, whose emitter is connected to the power supply, that is, the sensor power supply circuit 11 (see FIG. 1), and whose base is connected to the output port TP. Similarly to the NPN transistor TRN described above, the driving is controlled by the microcomputer 10.

Next, the operation of the first embodiment of the present invention when the short circuit 13 short-circuits the input terminal e to the power supply (corresponding to claim 3) will be described with reference to the flowchart of FIG. 5 together with FIG. . In FIG. 5, S1 to S5 are the same steps as in FIG. In this case, the polarity of the PNP transistor TRP has been inverted, so step S2
3 differs only in that S3 and S3 are replaced.

First, it is determined whether or not the AD conversion request flag is set (step S1). If not set, the output port TP is set to "L" level to execute the contact failure prevention mode, and PNP is set. Transistor TR
P is turned on to drive the short circuit 13 (step S
3).

As a result, the resistor RB in the short circuit 13 is
The current adjusted by the sensor power supply circuit 11
PNP transistor TRP, resistor RB, input source terminal e of sensor detection circuit 12, signal line LD, output terminal b of torque sensor 2, resistor RS in torque sensor 2, ground terminal c of torque sensor 2, ground line LG , The ground terminal f of the sensor detection circuit 12 and the ground.

Also in this case, since the sensor power supply circuit 11 applies a sufficient predetermined voltage to the current flowing from the sensor power supply circuit 11 to the ground, the input / output terminal b
Even if an oxide film that causes poor contact exists in the connector portion including and e, the oxide film can be destroyed and a good contact state can be maintained.

On the other hand, in step S1, a flag requesting AD conversion is set (that is, YE).
If it is determined to be S), it means that the motor 3 can be controlled based on the AD conversion value. Therefore, the microcomputer 10 sets the output port TP to the “H” level in order to execute the operation in the normal control mode. The driving of the short circuit 13 is stopped (step S3).

Thereafter, similar to the above, the AD conversion port TS
Is AD-converted (step S4), the output value for the motor 3 is determined based on the AD-converted value, and a motor drive signal is output to the motor drive circuit 14 (step S5).

Example 2. (Corresponding to claim 7) In the first embodiment, the signal delay due to the filter in the sensor detection circuit 12, that is, the resistor R and the capacitor C is not considered, but the signal delay after the short circuit 13 is stopped is compensated. It is desirable to do. Next, with reference to the circuit configuration diagram of FIG. 2 and the flowchart of FIG. 6, a second embodiment of the present invention will be described in which timer means is added to perform signal delay compensation.

First, the input delay of the detection signal D to the AD conversion port TS after the short circuit 13 is stopped will be described. In FIG. 2, the output port TP is from "L" to "H".
Then, the short circuit 13 is driven (the NPN transistor TRN is turned on) and the voltage level of the input terminal e decreases. At this time, the voltage drop timing of the voltage level of the AD conversion port TS is delayed due to the filter action of the resistor R and the capacitor C in the sensor detection circuit 12.

Similarly, when the output port TP changes from "H" to "L", the short circuit 13 stops driving (NPN).
Although the transistor TRN is turned off) and the voltage level of the input terminal e is restored, the voltage level of the AD conversion port TS also delays the voltage restoration timing due to the filtering action of the resistor R and the capacitor C at this time.

This is the same not only in the case of FIG. 2 but also in the case of FIG. 4, and immediately after the voltage level of the output port TP is switched, the value of the AD conversion port TS is set to AD.
Even if you convert it, you will not be able to enter the correct value.

Therefore, in the second embodiment of the present invention, timer means is inserted at the input side of the AD converter in the microcomputer 10.
The AD converter is enabled after a normal value can be input. That is, in the processing operation, as shown in FIG. 6, for example, after it is determined in step S1 that the AD conversion request flag is set (that is, YES), the output port TP is set to the “L” level to drive the short circuit 13. At the same time as stopping (step S3), the timer processing step S5 is executed.

In this case, the timer means has a time longer than the filter time constant determined by the resistor R and the capacitor C in the sensor detection circuit 12 (for example, 100 m).
s) is set in advance, and waits for a predetermined time (100 ms) to elapse in step S6. As a result, while waiting for the elapse of a predetermined time, AD
The voltage level of the input value (the detection signal D of the torque sensor 2 via the sensor detection circuit 12) of the conversion port TS becomes stable.

After the elapse of a predetermined time, the input value of the AD conversion port TS is AD-converted as described above (step S
4), the motor output value is determined based on the AD conversion value of the detection signal D, and the motor drive signal is output to the motor drive circuit 14 to control the motor 3 (step S5). As a result,
Further, a stable and highly reliable sensor control device can be realized.

Although the processing routine of FIG. 6 is applied to the device having the circuit configuration of FIG. 2, it is applied to the device of the circuit configuration of FIG. The process routine is the same as that of FIG. 6 except that steps S2 and S3) are reversed as shown in FIG.

As a processing operation for validating the AD converter after the lapse of a predetermined time, the execution of the AD conversion is made to stand by in step S6 and the AD conversion is executed in step S4 after the standby. May be delayed. That is, instead of step S6, AD conversion is constantly executed to store the AD conversion value in the RAM, and instead of step S4, the output port TP is set to "A" from the AD conversion value stored in the RAM. The AD conversion value may be read after 100 ms has elapsed from the L level.

Here, taking the case of the electric power steering controller as an example, the operation relating to the second embodiment of the present invention will be described more specifically with reference to FIGS. 7 and 8 together with FIG.

FIG. 7 is a characteristic diagram showing the relationship between the steering torque TZ generated by the motor 3 and the motor current IM. FIG. 8 is a waveform diagram showing the signal levels of the AD conversion port TS and the output port TP, showing changes in the input value VTS of the AD conversion port TS before and after the operation of the short circuit 13.

The microcomputer 10 in the control device 1 determines the motor drive signal according to the detection signal D (steering torque value) from the torque sensor 2 and supplies the motor current IM corresponding to the motor drive signal to the motor 3. Motor current IM at this time
The relationship between [A] and the generated steering torque TZ [N · m] is as shown in FIG. 7.

From FIG. 7, the motor current IM is fixed to 0 in the range of the steering torque TZ from 0 to TZ1, and the motor current I is maintained when the steering torque TZ is TZ2 (> TZ1) or more.
M is fixed to the maximum current IM2 and the steering torque TZ is TZ.
The motor current IM is 0 to IM2 in the range of 1 to TZ2.
It can be seen that it fluctuates between.

Further, the following can be seen from the time-dependent correlation between the signal level VTP of the output port TP and the signal level of the input value of the AD conversion port TS shown in FIG. That is, the signal level VTP of the output port TP changes during the period TON (short-circuit driving of the short-circuit 13) during the period of "H" and to "L" level (stops the short-circuit driving of the short-circuit 13 and opens).
AD conversion port TS after 100 ms has passed
Signal level VTS is low, and a normal value cannot be obtained even if the input value VTS at this time is AD-converted.

Therefore, the signal level VTP of the output port TP is set to "L" (short circuit 13 is opened), and after a predetermined time (100 ms) has elapsed, the AD conversion port TS.
A normal AD change value can be obtained by AD converting the input value VTS.

From FIGS. 7 and 8, for example, when the short circuit 13 is driven when the steering torque TZ is in the range of TZ1 to TZ2, the steering torque TZ is driven while the short circuit 13 is being driven.
Since the input value VTS corresponding to V cannot be AD-converted, the steering torque equivalent value V
The TS will be input.

As a result, a region where the steering torque equivalent value VTS cannot be input occurs every time the short circuit 13 is driven, and when the steering torque TZ changes in this region, the motor current IM is changed according to the steering torque TZ. Also changes. In the electric power steering device, this change in the motor current IM causes an uncomfortable feeling in the steering feeling of the steering wheel, which is not preferable.

However, if the short circuit 13 is driven when the steering torque TZ is in the range of 0 to TZ1 or TZ2 or more, even if the detected value VTS of the steering torque TZ changes while the short circuit 13 is being driven, the motor current is reduced. IM hardly changes. That is, the AD conversion value of the steering torque TZ is 0 to TZ.
In the range of 1 or TZ2 or more, the motor current IM is fixed to 0 or the maximum current IM2, so that the motor current IM does not change even if the steering torque TZ slightly changes during the driving of the short circuit 13.

As a result, there is no change in the motor current IM,
In the electric power steering system, there is no influence on the steering feeling of the steering. When the steering torque TZ is in the range of 0 to TZ1 or TZ2 or more, the motor current IM is fixed to 0 or the maximum current IM2, and therefore the AD conversion value of the steering torque TZ is not used for control.

Example 3. (Corresponding to claim 8) In the second embodiment, the failure determination of the torque sensor 2 was not taken into consideration, but the failure determination of the torque sensor 2 is performed at the time of connection such as battery replacement or at the time of initial installation of the control device 1. It is desirable to stop the control of the motor 3 when determining a defect. A third embodiment of the present invention will be described below with reference to the circuit configuration diagram of FIG. 2 and the circuit diagram of FIG. 9 and the flowchart of FIG.

In this case, the microcomputer 10 in the control device 1
Is the torque from the detection signal AD-converted (AD conversion value) while the short circuit 13 is open and the detection signal AD-converted (AD conversion value) while the short-circuit means is short-circuited when the control device 1 is activated. Sensor resistance value calculating means for calculating the resistance value RSo of the sensor 2, sensor failure determining means for determining a failure of the torque sensor 2 based on the resistance value RSo, and control of the motor 3 (control target) at the time of sensor failure determination. And a control stopping means for stopping.

First, referring to FIG. 9, the short circuit 13
The detection signal D from the torque sensor 2 when the driving is stopped and when the driving is performed will be described. FIG. 9 is a circuit diagram schematically showing the torque sensor 2, the sensor detection circuit 12, and the short circuit 13, where VS is a power supply voltage and VTS is an AD conversion port T.
It is an input value of S. Further, RS1 and RS2 indicate a variable resistor RS, and a switch SW is an NPN transistor T.
RN is shown.

The variable resistor RS of the torque sensor 2 is RS1.
And RS2, and the power supply voltage VS is applied. Further, when the control device 1 is started, it is assumed that there is no contact resistance between the output terminal b on the torque sensor 2 side of the connector and the input terminal e on the control device 1 side, and each terminal is omitted.

In FIG. 9, the resistance value RMo of the resistor RM for disconnection detection is sufficiently larger than the resistance value RS2o of the resistor RS2 obtained by disassembling the variable resistor RS of the torque sensor 2, for example, RMo = RS2o × 1000. It is set to meet the requirements. Therefore, the combined resistance value of the resistors RS2 and RM can be regarded as almost RS2, ignoring the resistance value RMo.

Here, the detection signal D of the torque sensor 2 when the NPN transistor TRN (switch SW) is off.
Voltage level, that is, input value VTS (OFF) [V]
Is expressed by the following equation (1) using the resistance value RS1o of the resistor RS1.

VTS (OFF) = {RS2o / (RS1o + RS2o)} × VS ... (1)

The input value VTS (ON) [V] when the switch SW is on is represented by the following equation (2) using the resistance value RBo of the resistor RB.

VTS (ON) = [{RS2o.RBo / (RS2o + RBo)} / {RS1o + RS2o.RBo / (RS2o + RBo)}] × VS ... (2)

Using the above equation (1), the resistance value RS2o in the torque sensor 2 can be calculated from the input value VTS (OFF) when the switch SW is off. Also,
Since the resistance value RBo of the resistor RB for current adjustment and the sensor power supply voltage VS are fixed values, the combined resistance value of the resistance values RS2o and RBo can be obtained using the above equation (2).

The resistance value RS1o of the resistor RS1 is
It can be obtained by subtracting the resistance value RS2o from the total resistance value RSo of the torque sensor 2. Therefore, when the switch SW is off, the input value VTS (O
FF), the input value VTS (O
N) can be calculated.

Next, with reference to FIG. 10, the operation of the third embodiment of the present invention for determining the failure of the torque sensor 2 will be described. First, at the time of starting when the control device 1 starts control, for example, when the microcomputer 10 resets and starts, the output port TP is set to the “L” level to turn off the switch SW (NPN transistor TRN),
The driving of the short circuit 13 is stopped (step S10).

Then, the input value VT of the AD conversion port TS
S (detection value of torque sensor 2) is AD-converted, and this AD
The converted value is stored in the RAM in the microcomputer 10 (step S11). Subsequently, using the AD conversion value stored in the RAM, the input value VTS (ON) 1 of the AD conversion port TS when the switch SW is turned on (driving the short circuit 13)
Is calculated by the equation (2) (step S12).

The input value VTS (ON) 1 calculated in step S12 is stored in the RAM in the microcomputer 10. Next, the output port TP is actually set to "H" level to turn on the switch SW to drive the short circuit 13 (step S13). Then, the actual input value VTS (ON) of the AD conversion port TS (detection value of the torque sensor 2)
Is AD-converted and the AD-converted value is stored in the RAM in the microcomputer 10 (step S14).

Subsequently, the AD conversion value stored in step 14 and the AD conversion value of VTS (ON) 1 calculated and stored in step 12 are compared to determine whether or not the comparison result is abnormal. (Step S15). If it is determined that the error between the calculated value VTS (ON) 1 and the AD conversion value is larger than a predetermined value (for example, 10% or more of the total resistance value) (that is, YES), it is considered that there is an error and an error flag is set. Is set (step S16).

On the other hand, if it is determined in step S15 that the error is less than 10% of the total resistance value (that is, NO), it is regarded as normal and the error flag is cleared (step S17). Thus, after operating the error flag in step S16 or S17, the main processing step S18 for controlling the motor 3 is executed.

Since the above steps S10 to S17 are executed only at the time of reset start, steps S10 to S17 are not executed after the main processing step S18 is executed. In addition, step S16 or S1
The error flag operated in 7 is used to determine whether the motor 3 is driven or not in the main processing step S18.

The processing routine of FIG. 10 shows the case where it is applied to the device having the circuit configuration of FIG. 2, but when it is applied to the device of the circuit configuration of FIG. 4, the drive logic of the short circuit 13 (steps S10 and It is the same as FIG. 10 except that S13) is reversed.

Example 4. (Corresponding to Claim 9) In the third embodiment, the control device 1 and the torque sensor 2 are provided.
Although no consideration was given to the defect of the connector portion connecting between and, it is desirable to determine the defect of the connector portion and stop the control of the motor 3 when the defect of the connector portion is determined.
Hereinafter, with reference to the circuit configuration diagram of FIG. 2 and the circuit diagram of FIG. 11 and the flowchart of FIG. 12, a fourth embodiment of the present invention for determining a defect of a connector portion will be described.

In this case, the microcomputer 10 in the control device 1
Is a signal line from the detection signal (AD conversion value) AD-converted while the short circuit 13 is open (non-driving) and the detection signal AD conversion value (AD conversion value) while the short circuit 13 is short-circuit driven. Contact resistance value calculating means for calculating the contact resistance value RCo of the connector portion including both ends of the LD, connector portion failure determining means for determining the failure of the connector portion based on the contact resistance value RCo, and a motor for determining the failure of the connector portion. Control stop means for stopping the control of 3).

First, the means for calculating the contact resistance value RCo will be described with reference to FIG. FIG. 11 schematically shows the torque sensor 2, the sensor detection circuit 12, and the short circuit 13, and in the figure, RS1, RS2, VS,
SW and VTS are the same as those described above, and RC is a resistor corresponding to the connector section including both terminals b and e of the signal line LD (see FIG. 2).

Here, the contact resistance of the input / output terminals b and e of the connector portion when the control device 1 is started is determined by the resistor R.
It is indicated by C. First, when the switch SW is off, the resistance value RMo of the resistor RM is sufficiently larger than the resistance value RS2o obtained by disassembling the torque sensor 2 as described above. Therefore, the combined resistance of the resistor RS2 and the resistors RM and RC value is,
It can be considered as RS2.

Further, the contact resistance value RCo of the connector is
Assuming that the resistance RM of the resistor RM is 1/10 or less of that of the resistor RM,
Torque sensor detection value when the short circuit 13 is off, that is, A
The input value VTS (OFF) of the D conversion port TS is expressed by the following equation (3).

VTS (OFF) = {RS2o / (RS1o + RS2o)} × {RMo · RC o / (RMo + RCo)} × VS ... (3)

Here, the contact resistance value RCo is the resistance value RM.
Since the value is one-tenth or less of o, the above formula (3)
Can be approximated by the following equation (4).

VTS (OFF) = {RS2o / (RS1o + RS2o)} × VS ... (4)

On the other hand, when the switch SW is on, the resistance value RMo is sufficiently larger than the resistance RBo.
The combined resistance value of RM and RM can be regarded as RB.
Therefore, the torque sensor detection value when the switch SW is on, that is, the input value VTS (ON) of the AD conversion port TS.
Is expressed by the following equation (5).

VTS (ON) = [{RS2o · (RBo + RCo) / (RS2o + RBo + RCo)} / {RS1o + RS2o · (RBo + RCo) / (RS2o + RBo + RCo)}] × {RBo · RCo / (RBo + RCo)} × VS ... (5) )

Using the above equation (3), the input value VTS (O
FF), the resistance value RS2o in the torque sensor 2 is estimated, and the input value VTS when the contact resistance value RCo is 0 [Ω]
(ON) 1 can be obtained by calculation, and the difference between the calculated value VTS (ON) 1 and the actual input value VTS (ON) can be obtained. Further, the current value IRB flowing through the resistor RB in the short circuit 13 is calculated from the calculated value VTS (ON) 1 and the calculated value VT
The contact resistance value RCo can be estimated from the current value IRB and the difference between S (ON) 1 and the actual input value VTS (ON).

Next, the operation of the fourth embodiment of the present invention will be described with reference to FIG. In FIG. 12, S
10 to S14 and S18 are the same steps as in FIG. 10, and S15A to S17A are steps S15 to S1.
It corresponds to 7. In this case, the AD conversion step S14
Between the determination step S15A and the determination step S15A, a step S19 for estimating the resistance value RCo is inserted.

First, the output port TP is set to the "L" level (N
The PN transistor TRN is turned off to stop driving the short circuit 13 (step S10), and the AD conversion port TS
The input value VTS (OFF) of is AD-converted (step S1
1), the input value VTS (ON) 1 of the AD conversion port TS when the short circuit 13 is driven using this AD converted value
Is calculated (step S12).

Then, the output port TP is set to "H" level to drive the short circuit 13 (step S13), and the input value VTS (ON) of the AD conversion port TS is AD-converted (step S14). Next, the AD conversion value obtained in step S14 and the input value VTS calculated in step 12
The contact resistance RCo of the connector terminal, that is, the input / output terminals b and e is obtained from the absolute value of the deviation from the AD conversion value of (ON) 1 (step 19).

Then, the judgment value RH of the contact resistance value stored in the RAM is compared with the contact resistance value RCo to judge whether or not the contact resistance value RCo is equal to or larger than the judgment value RH (abnormal) (step S15A). . If it is determined that RCo ≧ RH (that is, YES), the connector section is considered to be abnormal and an error flag is set (step S16A), and R
If it is determined that C <RH (that is, NO), the connector section is regarded as normal and the error flag is cleared (step S17A).

Thus, step S16A or S17
After the error flag is operated in A, the main processing step S18 for controlling the motor 3 is executed, and after the main processing step S18 ends, the process returns to step 10 to repeat the above processing. Step S16A or S
The error flag operated in 17A is used to determine whether to drive or not drive the motor 3 in the main processing step S18. It goes without saying that this case can be applied not only to the device having the circuit configuration shown in FIG. 2 but also to the device having the circuit configuration shown in FIG.

Example 5. (Corresponding to claim 10) In each of the above embodiments, the AD converter is disabled during the short circuit operation of the short circuit 13, but the input value VTS during the short circuit operation of the short circuit 13 may be held. Good. Embodiment 5 of the present invention will now be described with reference to the circuit configuration diagram of FIG.
Will be described.

In this case, the control device 1 includes a detection signal holding section that holds the detection signal D when the short circuit 13 is short-circuited until the short circuit 13 is opened again. FIG. 13 shows a case in which an NPN transistor TRN is used as the short circuit 13, 1, 2, 10, 12 and 13 are the same as those described above. .

AS is an analog switch inserted in the input terminal side of the filter in the sensor detection circuit 12, and IV is analog switch A in response to the signal level of the output port TP.
It is an inverter that turns S on and off. The analog switch AS has a function as a sample hold circuit,
A detection signal holding unit that holds a signal when it is off is configured.

In FIG. 13, the difference from FIG. 2 is that the analog switch AS is inserted in the sensor detection circuit 12 and the drive signal (output port TP) from the microcomputer 10 to the short circuit 13 is at the “L” level (NPN). Transistor TR
The point is that the analog switch AS is turned on by the inverter IV when N is turned off and the short circuit 13 stops driving.

In this way, the short circuit 1
When the "L" level signal for the third switch turns on the analog switch AS via the inverter IV, the torque sensor 2
Detection signal D from AD is passed through filters R and C to AD
It is applied to the conversion port TS.

On the contrary, the drive signal from the microcomputer 10 to the short circuit 13 is at "H" level (NPN transistor TR).
When N is on and the short circuit 13 is short-circuited), the "H" level signal from the microcomputer 10 to the short circuit 13 turns off the analog switch AS via the inverter IV. As a result, the analog switch AS outputs the detection signal D immediately before being turned off to the AD conversion port TS.

Therefore, since the detection signal D from the torque sensor 2 does not change depending on the ON / OFF drive state of the short circuit 13, AD conversion can be performed regardless of the drive state of the short circuit 13.

Although the NPN transistor TRN is used as the switching element in the short circuit 13 here, the PN having the opposite polarity is used.
The P transistor TRP may be used. FIG. 14 is a circuit configuration diagram showing a fifth embodiment of the present invention when a PNP transistor TRP is used as the short circuit 13, 1.
2, 10, 12, 13 and AS are the same as those described above, and the outline of the operation is the same as in the case of FIG.

In FIG. 14, IB is a buffer for driving the analog switch AS on and off. In this case, the difference from FIG. 4 is that the analog switch AS is inserted as in FIG. 13, and the drive signal from the microcomputer 10 to the short circuit 13 is at the “H” level (PNP transistor TRP).
Is off and the short circuit 13 is stopped driving), the analog switch AS is turned on by the buffer IB.

Thus, the short circuit 1
When the "H" level signal for 3 turns on the analog switch AS via the buffer IB, the detection signal D from the torque sensor 2 is directly applied to the AD conversion port TS via the filters R and C.

On the contrary, the drive signal from the microcomputer 10 to the short circuit 13 is at the "L" level (PNP transistor TR
When P is turned on and the short circuit 13 is short-circuited), the "L" level signal from the microcomputer 10 to the short circuit 13 turns off the analog switch AS via the buffer IB.
As a result, the analog switch AS outputs the detection signal D immediately before being turned off to the AD conversion port TS.

Therefore, as described above, the short circuit 13
Since the detection signal D from the torque sensor 2 does not change depending on the ON / OFF driving state of A, AD conversion can be executed regardless of the driving state of the short circuit 13. in this case,
Since the inexpensive analog switch AS can be used, the cost does not increase.

Although the analog switch AS is used as the detection signal holding unit in FIGS. 13 and 14, it can be realized by combining the switching element with the capacitor C which constitutes the filter. Embodiment 5 of the present invention in which a capacitor C is combined with a switching element will be described below with reference to the circuit configuration diagram of FIG.

FIG. 15 shows a case where the NPN transistor TRN is used as the short circuit 13, 1, 2, 10, 1.
Since the outline of the operations regarding 2, 13, and IV is the same as that described above, detailed description thereof will be omitted. TRNH is a grounded NPN
It is a transistor, the collector is connected to the capacitor C, and the base is connected to the output terminal of the inverter IV. The NPN transistor TRNH cooperates with the capacitor C to form a detection signal holding unit.

In this case, the difference from FIG. 2 is that an NPN transistor TRNH is inserted between the capacitor C and the ground, and the inverter I is driven by the drive signal (signal level of the output port TP) from the microcomputer 10 to the short circuit 13.
The point is that the NPN transistor TRNH is driven via V.

That is, when the output port TP is set to the “H” level and the short circuit 13 is short-circuit driven, the NPN transistor TRNH is turned off by the “L” level signal from the inverter IV, and the capacitor C in the sensor detection circuit 12 is turned off. It will float the ground level.

As a result, the electric charge immediately before driving the short circuit 13 is stored in the capacitor C without being discharged as it is. In this case, after driving the short circuit 13,
Even if the driving of the short circuit 13 is stopped again and opened, the input voltage value VTS of the AD conversion port TS corresponding to the detection signal D
Immediately returns to the value immediately before driving the short circuit 13 without delaying the filter by the resistor R and the capacitor C. Therefore, it is not necessary to provide timer means.

Although FIG. 15 shows the case where the NPN transistor TRN is used as the short circuit 13, the PNP transistor TRP may be used. FIG. 16 shows the short circuit 1
FIG. 3 is a circuit configuration diagram when a PNP transistor TRP is used as 3, and the outline of the operation is the same as that described above, and a detailed description thereof will be omitted.

In this case, the difference from FIG. 15 is that the short circuit 13 is formed of the PNP transistor TRP and the inverter IV is removed. Therefore, when the short circuit 13 is driven, the NPN transistor TRNH floats the ground level of the capacitor C in the sensor detection circuit 12 by the “L” level signal from the output port TP.

As a result, similarly to the above, the capacitor C
The electric charge immediately before driving the short-circuit 3 is accumulated and held without being discharged. When the short-circuit 13 is stopped again after that, the input voltage value VTS to the AD conversion port TS is short-circuited without a filter delay. The value immediately before the driving of the circuit 3 is restored.

Example 6. (Corresponding to Claim 11) In each of the above embodiments, the case where the detection signal D from the single torque sensor 2 is detected by the single sensor detection circuit 12 has been described. The signal may be detected by a plurality of sensor detection circuits.

A sixth embodiment of the present invention in which a plurality of torque sensors are arranged in parallel will be described below with reference to FIGS. In FIG. 17, 2a and 2b are a plurality of torque sensors arranged in parallel, 12a and 12b are a plurality of sensor detection circuits arranged in parallel in the control device 1A corresponding to the torque sensors 2a and 2b, 13a and 13b are It is a plurality of short-circuit circuits arranged in parallel corresponding to each sensor detection circuit 12a and 12b. Here, the detailed description is omitted because it is the same as that of FIG. 2 except that each circuit configuration is arranged in parallel.

In this case, the microcomputer 10 in the control device 1A
A is the AD conversion ports TS1 and TS2 corresponding to the sensor detection circuits 12a and 12b, and the short circuit 13
Output ports TP1 and TP corresponding to a and 13b
2 and AD of each torque sensor 2a and 2b
The short-circuit means associated with the unconverted torque sensor is opened and closed sequentially.

FIG. 17 shows, for example, a case where two types of torque sensors 2a and 2b are used, and sensor detection circuits 12a and 12b and short circuit circuits 13a and 13b are provided in the same number as torque sensors 2a and 2b. ing.

FIG. 18 is a timing chart showing the operation timings of AD conversion and short-circuit drive. From FIG. 18, the torque sensors 2a and 2b alternate between short-circuit operation and A
It can be seen that D conversion is being performed. For example, the detection signal equivalent value on the torque sensor 2a side (AD conversion port TS1
Input value) VTS1 is AD-converted, the output port TP1 of the short circuit 13a on the torque sensor 2a side is set to the "L" level to turn off the NPN transistor TRN1 to stop the driving of the short circuit 13a.

On the other hand, at this time, AD conversion is not executed on the torque sensor 2b side, and the short circuit 1 on the torque sensor 2b side is not executed.
The output port TP2 of 3b is set to "H" level to turn on the NPN transistor TRN2, and the short circuit 13b is short-circuit driven. The above operation is periodically executed, for example.

Next, the operation of the sixth embodiment of the present invention will be described with reference to the flowchart of FIG. First, it is determined whether or not a flag requesting AD conversion on the torque sensor 2a side is set (step S20),
If it is determined that it is set (that is, YES), the output port TP1 for the short circuit 13a on the torque sensor 2a side is set to "L" level, and the NPN transistor TRN1 is turned off (step S21).

Further, the short circuit 13 on the side of the torque sensor 2b.
The output port TP2 for b is set to "H" level, and NP
The N-transistor TRN2 is turned on to short-circuit the short-circuit 13b (step S22). Then, the input value (detection value of the torque sensor 2a) of the AD conversion port TS1 on the torque sensor 2a side is AD-converted, and this AD conversion value is stored in the RAM in the microcomputer 10A (step S2).
3). Then, the flag requesting AD conversion on the torque sensor 2a side is cleared (step S24).

On the other hand, if it is determined in step S20 that the flag requesting AD conversion on the torque sensor 2a side is not set (that is, NO), the output port TP1 for the short circuit 13a on the torque sensor 2a side is set to " The "H" level is set, the NPN transistor TRN1 is turned on, and the short circuit 13a is driven (step S25).

The short circuit 13 on the torque sensor 2b side is also provided.
The output port TP2 for b is set to the “L” level and NP
The N-transistor TRN2 is turned off and the short-circuit 13b is short-circuit driven (step S26). Then, the input value (detection value of the torque sensor 2b) of the AD conversion port TS2 on the torque sensor 2b side is AD-converted, and this AD conversion value is stored in the RAM in the microcomputer 10A (step S2).
7). Then, a flag requesting AD conversion on the torque sensor 2a side is set (step S28).

Hereinafter, the motor output value is determined on the basis of the AD conversion values relating to the torque sensors 2a and 2b stored in the RAM, and the motor drive signal is output to the motor drive circuit 14 (see FIG. 1) to drive the motor 3. Control (step S29). Then, the process from step S20 is repeated again. Each time the process of steps S20 to S29 is repeated, the torque sensor to be AD-converted and the driven short circuit are alternately switched as shown in FIG.

Here, the short circuits 13a and 13
Although b is composed of the NPN transistors TRN1 and TRN2, the operation is similar when the short circuits 13a and 13b are composed of PNP transistors, except that the driving logics of the short circuits 13a and 13b are reversed.

In each of the above embodiments, the short circuit 13,
Although a transistor is used as the switching element in 13a and 13b, a relay or the like may be used instead of the transistor. Further, the above embodiments can be combined,
Thereby, a synergistic effect can be obtained.

Further, although the torque sensors 2, 2a and 2b are used as the sensors in the case of being applied to the electric power steering control device as an example, it is needless to say that the present invention can be applied to not only the torque sensor but also any sensor.

[0157]

As described above, according to claim 1 of the present invention, a sensor for outputting a detection signal related to a controlled object,
An AD converter for converting the detection signal into a digital signal,
A control device that controls a control target using the AD-converted detection signal, a signal line that connects between an output terminal of the sensor and an input terminal of the control device, a power supply terminal of the sensor, and a power supply terminal of the control device. The control device is provided with a power supply line connecting between them and a ground line connecting between the ground terminal of the sensor and the ground terminal of the control device, and the control device short-circuits the input terminal of the control device to one of the power supply and the ground at a predetermined timing. Including a short-circuiting means, the short-circuiting means applies a predetermined voltage between the output terminal and the input terminal connected to both ends of the signal line through the power supply line or the ground line to supply a predetermined current,
Since the oxide film that causes an increase in the contact resistance of the signal line is destroyed, it is possible to prevent the occurrence of contact failure without using an expensive contact portion plated with gold or the like. Therefore, stable control is possible without the control AD conversion value fluctuating and adversely affecting the control, and a reliable contact failure countermeasure for the connector portion between the sensor and the control device and cost reduction. The control device can be obtained.

According to a second aspect of the present invention, in the first aspect, the short-circuit means comprises an opening / closing element whose one end is connected to the input terminal and the other end is grounded.
Since the switching element drive unit for closing and driving the switching element at a predetermined timing is included, the oxide film is destroyed by the current flowing through the switching element via the power supply line and the signal line.
It is possible to obtain a sensor control device that realizes a reliable countermeasure against contact failure of the connector portion between the sensor and the control device and cost reduction.

According to a third aspect of the present invention, in the first aspect, the short-circuiting means comprises an opening / closing element whose one end is connected to the input terminal and the other end is connected to the power source, and the control device is a predetermined device. The connector part between the sensor and the control device includes the switching element drive part that closes and drives the switching element at the timing, and the oxide film is destroyed by the current flowing from the switching element through the signal line and the ground line. There is an effect that a sensor control device that realizes reliable contact failure countermeasures and cost reduction can be obtained.

According to a fourth aspect of the present invention, in the second or third aspect, the short-circuiting means includes a limiting resistor that limits a current flowing through the switching element, and the switching element and the switching element driving section are provided. Since the constituent transistor elements are prevented from being destroyed, it is possible to obtain a sensor control device in which failure of the switching element and the switching element driving section is prevented and safety is improved.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, the predetermined timing is when the AD converter is not operating and is generated when the short-circuit means is driven. Since the noise and the fluctuation of the detection signal are not influenced on the AD conversion value, there is an effect that a sensor control device realizing stable control can be obtained.

According to a sixth aspect of the present invention, in the sensor control device according to any one of the first to fourth aspects, the predetermined timing is set when the control device is not driving the controlled object, and the short-circuiting means is provided. Since the noise and the fluctuation of the detection signal generated at the time of driving do not affect the control target, there is an effect that a sensor control device that realizes stable control can be obtained.

Further, a sensor control device according to a seventh aspect of the present invention is the sensor control device according to any one of the first to sixth aspects, wherein the control device turns on the AD converter after a predetermined time has elapsed since the short-circuit means was opened. By controlling the control target by using the AD conversion value after stabilization including the timer means for enabling, the noise generated when driving the short-circuiting means and the fluctuation of the detection signal do not affect the AD conversion value. Therefore, the AD conversion value will not be adversely affected by the noise generated when the short-circuiting means is driven or the delay of the detection voltage due to the filter circuit, and the sensor control device that realizes more stable control can be obtained. .

The sensor control device according to an eighth aspect of the present invention is the sensor control device according to any one of the first to seventh aspects, wherein the control device performs AD conversion during opening of the short-circuit means at the time of starting the control device. A sensor resistance value calculating means for calculating a resistance value of the sensor from the detected signal and the detection signal AD-converted during the short circuit of the short-circuiting means; and a sensor failure determining means for determining a sensor failure based on the resistance value. , Including control stop means for stopping control of the controlled object when the sensor is judged to be defective, and if the sensor resistance value differs from the set value by a predetermined amount, it is judged to be a sensor abnormality including sensor misassembly and the control is stopped. Since this is done, there is an effect that the safety and reliability are further improved and a sensor control device is obtained.

The sensor control device according to a ninth aspect of the present invention is the sensor control device according to any one of the first to eighth aspects, wherein the control device is the detection signal AD-converted while the short circuit means is open and the short circuit means. Contact resistance value calculating means for calculating the contact resistance value of the connector part including both ends of the signal line from the detection signal AD-converted during the short circuit of the connector part, and the connector part for determining the defect of the connector part based on the contact resistance value. Defect determination means,
A control stop means for stopping control of the controlled object when the connector section is judged to be defective, and if the contact resistance value of the connector section is different from the judgment value by a predetermined amount, it is judged that the connector section is defective and the control is stopped. Therefore, there is an effect that the safety and reliability are further improved and the sensor control device is obtained.

According to a tenth aspect of the present invention, in the sensor control device according to any one of the first to ninth aspects, the control device opens the detection signal when the short-circuit means is short-circuited. Since the detection signal holding unit that holds the detection signal is held until the short-circuiting unit is driven to prevent the detection signal from being changed when the short-circuiting unit is driven, even if the detection signal is AD-converted immediately after the driving of the short-circuiting unit, the control is affected. There is no problem, and the AD conversion can be performed by returning to the detection signal immediately before the driving of the short-circuiting means, and there is an effect that a sensor control device that realizes stable control without the influence of noise or the like generated when the short-circuiting means is driven can be obtained. .

Further, a sensor control device according to an eleventh aspect of the present invention is the sensor control device according to any one of the first to tenth aspects, in which a plurality of sensors are arranged in parallel, and the control device is an AD converter of the plurality of sensors. Since the short-circuiting means associated with the non-operated sensor is sequentially opened and closed to suppress the current consumption, there is an effect that a sensor control device in which deterioration of the control device and the sensor is delayed can be obtained.

[Brief description of drawings]

FIG. 1 is a circuit configuration diagram showing a first embodiment (corresponding to claims 1 to 6) of the present invention.

FIG. 2 is a circuit diagram showing a specific example (corresponding to claim 2) of the first embodiment of the present invention.

FIG. 3 is a flowchart showing an operation of the first embodiment shown in FIG.

FIG. 4 is another specific example of the first embodiment of the present invention (claim 3).
FIG.

FIG. 5 is a flowchart showing an operation of the first embodiment shown in FIG.

FIG. 6 is a flowchart showing the operation of the second embodiment (corresponding to claim 7) of the present invention.

FIG. 7 is a characteristic diagram showing the relationship between steering torque and motor current related to the operation of the second embodiment of the present invention.

FIG. 8 is a waveform diagram showing signal levels of an AD conversion port and an output port related to the operation of the second embodiment of the present invention.

FIG. 9 is a circuit diagram for explaining a sensor resistance value detecting operation according to a third embodiment (corresponding to claim 8) of the present invention.

FIG. 10 is a flowchart showing the operation of the third embodiment of the present invention.

FIG. 11 is a circuit diagram for explaining a contact resistance value detecting operation according to a fourth embodiment (corresponding to claim 9) of the present invention.

FIG. 12 is a flowchart showing the operation of the fourth embodiment of the present invention.

FIG. 13 is a fifth embodiment of the present invention (corresponding to claim 10).
3 is a circuit configuration diagram showing a case where an analog switch is used in FIG.

FIG. 14 is a circuit configuration diagram showing another example when an analog switch is used in the fifth embodiment of the present invention.

FIG. 15 is a fifth embodiment of the present invention (corresponding to claim 10).
3 is a circuit configuration diagram showing a case where an NPN transistor is used in FIG.

FIG. 16 is a circuit configuration diagram showing another example in which an NPN transistor is used in the fifth embodiment of the present invention.

FIG. 17 is a sixth embodiment of the present invention (corresponding to claim 11).
It is a circuit block diagram showing.

FIG. 18 is a timing chart for explaining the operation of the sixth embodiment of the present invention.

FIG. 19 is a flowchart showing the operation of the sixth embodiment of the present invention.

FIG. 20 is a circuit configuration diagram showing a conventional sensor control device.

[Explanation of symbols]

1 control device, 2 torque sensor, 3 motor (control target), 10 microcomputer, 11 sensor power supply circuit, 12
Sensor detection circuit, 13 short-circuit circuit, 14 motor drive circuit, AS analog switch (detection signal holding unit), D
Detection signal, LD signal line, LG ground line, LP power supply line, a, d power supply terminal, b output terminal, c, f ground terminal, e input terminal, RB limiting resistor, RS variable resistor, TRN NPN transistor, TRNH NP
N transistor (detection signal holding unit), TRP PNP transistor, TS AD conversion port, TP output port, step of determining during AD conversion, S2, S3 step of opening / closing short-circuit means, step of S4 AD conversion, step of S5 motor control Step, S6 step for elapse of a predetermined time (timer means), S15 step for determining defective sensor, S15A step for determining defective connector portion, S21, S22, S25, S26.
Steps to open and close sequentially.

Claims (11)

[Claims] 1. A control that includes a sensor that outputs a detection signal related to a control target and an AD converter that converts the detection signal into a digital signal, and controls the control target using the AD-converted detection signal. A device, a signal line connecting between an output terminal of the sensor and an input terminal of the control device, a power supply line connecting between a power supply terminal of the sensor and a power supply terminal of the control device, and the sensor In a sensor control device including a ground line connecting a ground terminal and a ground terminal of the control device, the control device short-circuits an input terminal of the control device to one of a power supply and a ground at a predetermined timing. A short circuit means between the output terminal and the input terminal connected to both ends of the signal line via the power supply line or the ground line. A sensor control device characterized in that a predetermined voltage is applied to the sensor to supply a predetermined current. 2. The short-circuiting device comprises an opening / closing element having one end connected to the input terminal and the other end grounded, and the control device drives the opening / closing element to close-drive the opening / closing element at the predetermined timing. The sensor control device according to claim 1, further comprising a unit. 3. The short-circuit means is composed of an opening / closing element having one end connected to the input terminal and the other end connected to a power source, and the control device is an opening / closing element for closing and driving the opening / closing element at the predetermined timing. The sensor control device according to claim 1, further comprising an element driving unit. 4. The sensor control device according to claim 2, wherein the short-circuit means includes a limiting resistor that limits a current flowing through the switching element. 5. The predetermined timing is when the AD converter is not operating.
5. The sensor control device according to claim 4. 6. The sensor control device according to claim 1, wherein the predetermined timing is when the control device is not driving the controlled object. 7. The control device according to claim 1, further comprising timer means for enabling the AD converter after a lapse of a predetermined time from the opening of the short-circuit means. Sensor controller. 8. The control device is configured such that, when the control device is started, the detection signal AD-converted while the short-circuiting device is open and the A-signal during the short-circuiting of the short-circuiting device.
A sensor resistance value calculation unit that calculates a resistance value of the sensor from the D-converted detection signal; a sensor failure determination unit that determines a failure of the sensor based on the resistance value; 8. The sensor control device according to claim 1, further comprising a control stop means for stopping control of a controlled object. 9. The control device, based on a detection signal AD-converted while the short-circuiting device is open and a detection signal AD-converted while the short-circuiting device is short-circuited, Contact resistance value calculating means for calculating a contact resistance value, connector portion defect determining means for determining a defect in the connector portion based on the contact resistance value, and stopping control of the control target when determining a defect in the connector portion A control stop means is included.
9. The sensor control device according to claim 8. 10. The control device according to claim 1, further comprising a detection signal holding unit that holds a detection signal when the short-circuit means is short-circuited until the short-circuit means is opened. Up to any sensor control device. 11. A plurality of the sensors are arranged in parallel, and the control device sequentially opens and closes a short-circuit means associated with a sensor which is not AD converted among the plurality of sensors. The sensor control device according to claim 10.