JPH0478123B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Application of the Invention] The present invention relates to an angle sensor that detects an angle between one member and another member. The present invention relates to a sensor failure detection device.

[Background of the invention]

Angle sensors that detect rotational angles between one member and another are used in many fields. In these fields, necessary calculations and controls are performed based on the detected values of angle sensors, and this allows machines,
Includes the field of implementing automatic control of equipment. If the angle sensor breaks down or its detection accuracy decreases for some reason, it is natural that it will become unusable as an angle sensor, but especially in the above-mentioned field of automatic control, incorrect values may be detected. Automatic control will be implemented based on this, and not only will machines and equipment not operate as expected, but they will also be at great risk.

Conventionally, in order to prevent such a situation, a failure detection device for detecting a failure of an angle sensor has been proposed. This failure detection device is configured to exclusively detect major accidents such as disconnection or short circuit of the angle sensor. However, failures of angle sensors include not only these major accidents, but also cases where, for example, there is a slight misalignment when the angle sensor is attached to the object to be detected, resulting in a slight error in the output. included. Especially when used for the above-mentioned automatic control, even if the output error of the angle sensor is small, the desired operation of the machine or device may not be obtained, and there is a risk that danger will occur if the output error is calculated. be.

[Purpose of the invention]

The purpose of the present invention is to solve the above-mentioned conventional problems,
An object of the present invention is to provide a failure detection device for an angle sensor that can detect the presence of even small detection errors due to installation errors.

[Summary of the invention]

In order to achieve the above object, the present invention provides an angle sensor failure detection device that detects a failure occurring in an angle sensor that detects an angle between a first member and a second member, in which the angle sensor itself a first setting value set near the maximum output value during normal operation;
A second setting value set near the minimum output value during normal operation of the angle sensor itself, and an output value of the angle sensor corresponding to the maximum angle determined by the configuration of the first member and the second member. a third setting value set to a slightly larger predetermined value; and a predetermined value slightly smaller than the output value of the angle sensor corresponding to the minimum angle determined by the configuration of the first member and the second member. and a fourth set value, which compares the detected value of the angle sensor with each of the set values, and an output means that outputs a failure signal in response to the result of this comparison. It is characterized by

When the ground side of the angle sensor is disconnected, the detected value will be higher than the first set value, and when the power side of the angle sensor is disconnected, the detected value will be lower than the second set value, and there may be an error in the installation or adjustment of the angle sensor. When the detected value is greater than or equal to the third set value or less than or equal to the fourth set value. When these situations occur, a failure signal is output and an alarm etc. is activated.

[Embodiments of the invention]

Hereinafter, the present invention will be explained based on illustrated embodiments.

FIG. 1 is a block diagram of an angle sensor failure detection apparatus according to an embodiment of the present invention. In the figure, 1 is the first
The members 2 and 2 are the second members and are rotatably connected to each other. 3 is an angle sensor attached to the center of rotation of the first member 1 and the second member 2;
Outputs a signal s proportional to the angle. 4 is a comparator composed of a microcomputer, etc., which inputs the detected value signal s from the angle sensor, and which will be described later.
Compare with two setting values. e ₁ to _{e 4} indicate failure signals that are output when the detection signal s has a predetermined relationship with each of the set values. 5 is each fault signal e ₁ to e ₄
This is a failure alarm device that operates according to the situation.

Next, the set values set in the comparator 4 will be explained with reference to FIGS. 2 and 3. FIG. 2 is a diagram showing the angular relationship between the first member 1 and the second member 2,
FIG. 3 is an output characteristic diagram of the angle sensor. In FIG. 3, the horizontal axis represents the angle, and the vertical axis represents the output value of the angle sensor. In this embodiment, the angle sensor 3 is composed of a potentiometer that outputs a voltage proportional to the rotation angle of its input shaft, and one end of the potentiometer is connected to a voltage source of voltage s _F. and the other end is grounded. Further, due to the mechanism of both, the rotation between the first member 1 and the second member 2 is assumed to be between the minimum angle Θ ₂ and the maximum angle Θ ₃ as shown in FIG. The angle sensor 3 is configured such that the output voltage s ₂ is output when the angle is Θ ₂ , and the output voltage s ₃ is output when the maximum angle is Θ ₃ .
shall be installed and the amplifier adjusted.

First, the first set value will be explained. Now, if a disconnection occurs on the ground side of the potentiometer,
The output voltage from the angle sensor 3 is approximately equal to the applied voltage s _F regardless of the angle between the first member 1 and the second member 2. Therefore, a value s ₄ close to this applied voltage s _F (for example, 95% of the applied voltage S _F ) is set as the first set value, and the angle sensor 3
If the output signal s exceeds the first set value _s4 , it can be determined that a disconnection accident has occurred on the ground side of the angle sensor 3.

Next, the second set value will be explained. This time, conversely, if a disconnection accident occurs on the voltage source side of the potentiometer, the output voltage from the angle sensor 3 will be the same regardless of the angle between the first member 1 and the second member 2. It becomes almost 0 (ground voltage). Therefore,
A value _s1 close to 0 voltage (for example, a voltage of 5% of the applied voltage _sF ) is set as the second set value, and even if the output signal s of the angle sensor 3 is less than the second set value _s1 . For example, it can be determined that a disconnection accident has occurred on the voltage source side of the angle sensor 3.

Furthermore, the third set value will be explained. now,
For example, when installing an angle sensor, if a deviation occurs in the installation, when the angle between the first member 1 and the second member 2 is Θ ₃ , a signal exceeding the electrical value s ₃ will be output. or, when the angle between them is Θ ₂ , a signal less than said value s ₂ is output. Therefore, the value s ₃ may be selected as the third set value, but in reality, due to the temperature characteristics of the angle sensor 3, etc., the signal s ₃ is accurately set at the angle Θ ₃ .
is not output, but the signal _s3 changes slightly.
For this reason, the signal s ₃ is given a certain tolerance value _ΔS determined based on various elements of the angle sensor 3, and the value s ₃₃ determined by s ₃₃ =s ₃ +Δs is set as the third set value.

Based on the same idea, the fourth setting value is set to the value s ₂₂ determined by s ₂₂ = s ₂ −Δs.

The relationship between the above set values is clear from the graph in FIG. In the graph of FIG. 3, a broken line indicates a state in which there is a failure due to the above-mentioned mounting misalignment, and the mounting misalignment is such that a signal larger than a predetermined signal is output. That is, in this case, when the angle between the first member 1 and the second member 2 reaches an angle Θ _E that is close to the angle Θ ₃ , the output signal s of the angle sensor 3 becomes the value s ₃₃ , which is Angle sensor 3 by comparing with the setting value of 3.
It can be determined that a failure exists in the If the mounting misalignment is such that a signal smaller than the predetermined signal is output, a failure can be determined based on the fourth set value s ₂₂ when the actual angle becomes close to the angle Θ ₂ . I can do it.

Next, the operation of this embodiment will be explained with reference to the flowchart shown in FIG. Incorporate the output signal s from the angle sensor 3 into the comparator 4 (procedure
s ₁ ) and compare whether the signal s is less than the second set value s ₁ (step s ₂ ). If the second set value s is less than ₁ , it is determined that a disconnection fault has occurred on the voltage source side of the potentiometer, and a failure signal e ₁ is output (procedure
s ₃ ), causing the failure alarm device 5 to take a corresponding action. When the signal s is greater than or equal to the second set value s ₁ , the signal s is compared with the fourth set value s ₂₂ (step s ₄ ). If the fourth set value s is less than ₂₂ , it is determined that there is an error in the installation or adjustment of the angle sensor 3, and a failure signal e ₂ is output (step s ₅ ), and the failure alarm device 5 is activated accordingly. .

When the signal s is greater than or equal to the fourth set value s ₂₂ , the signal s is then compared with the first set value s ₄ (step s ₆ ).
If the value exceeds the first set value _s4 , it is determined that a disconnection has occurred on the ground side of the potentiometer, and a failure signal _e4 is output (step _s7 ), and the The failure alarm device 5 is activated. When the signal s is determined to be less than or equal to the first set value s ₄ , the signal s is finally compared with the third set value s ₃₃ (procedure
_s8 ). If the value exceeds the third set value _s33 , it is determined that there has been an error in the installation or adjustment of the angle sensor 3, and a failure signal _e3 is output (step _s9 ), and a failure alarm is issued accordingly. Activate the device 5.

If it is determined that the signal s is less than the third set value _s33 , it is determined that there is no disconnection accident in the angle sensor 3, and the process returns to step _S1 , takes in a new output signal s, and repeats the same process again. Repeat the steps. During operation of the machine or device, when the angle between the first member 1 and the second member 2 approaches the angle Θ ₂ or the angle Θ ₃ , a failure due to incorrect installation or adjustment of the angle sensor 3 may occur. If so, this will be detected.

The failure detection device 5 can change the tone, the length of the intermittent signal, etc. according to the failure signal, and can distinguish between failures and issue an alarm. Moreover, a display device or an automatic stop device can be used in place of the failure alarm device 5, or they can be used together.

As described above, in this embodiment, the comparator is set with a first set value that is slightly lower than the maximum output value of the angle sensor itself and a second set value that is slightly higher than the minimum output value, so that the output signal of the angle sensor and Since the angle sensor is compared with these set values, accidents such as disconnection of the angle sensor can be immediately detected. Also, in the same comparison device, a third set value that is higher by a predetermined tolerance value than the detected value corresponding to the maximum angle that the first member and the second member can take, and a detected value that corresponds to the minimum angle that can be taken. By setting a fourth set value that is lower by the relevant tolerance value and comparing the output signal of the angle sensor with these set values, relatively small detection errors caused by installation errors and adjustment errors of the angle sensor can be avoided. It is also possible to detect the presence of the signal, and also to determine whether the error is shifting toward the higher or lower output signal side.

In addition, in the description of the above embodiment, an example was explained in which the output signals of the angle sensors are compared, but it is also possible to adopt a method in which the output signals are converted into angles and compared. Furthermore, it is clear that the present invention can also be applied to angle sensors whose output is not proportional to the rotation angle. Furthermore, in the description of the above embodiments, the angle sensor is composed of a potentiometer, but the present invention is also applicable to other types of angle sensors, such as rotary encoders.

〔Effect of the invention〕

As described above, in the present invention, the comparison device includes
The first set value and the second set value are set near the maximum output value and minimum output value of the angle sensor, and the output signal of the angle sensor is compared with these set values, so wire breakage etc. A major accident can be detected immediately, and the third setting value and the fourth setting value are set near the maximum output value and minimum output value corresponding to the maximum angle and minimum angle that the angle detection target can take. Since the output signal of the angle sensor is compared with the third set value and the fourth set value, it is possible to detect the presence of small detection errors caused by installation errors, adjustment errors, etc. of the angle sensor. It is also possible to determine the direction of the error shift.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a failure detection device for an angle sensor according to an embodiment of the present invention, and FIG. 2 is a side view showing the mutual angular relationship of the angle detection target members shown in FIG. 1.
Figure 3 is an output characteristic diagram of the angle sensor shown in Figure 1;
FIG. 4 is a flowchart illustrating the operation of the angle sensor failure detection device shown in FIG. 1...first member, 2...second member, 3...
Angle sensor, 4... Comparison device, 5... Failure alarm device.

Claims (1)

[Claims] 1 In an angle sensor failure detection device that detects a failure occurring in an angle sensor that detects an angle between a first member and a second member, the angle sensor itself is set to a maximum output value during normal operation. The first
a second setting value set near the minimum output value during normal operation of the angle sensor itself, and a maximum angle determined by the configuration of the first member and the second member of the angle sensor. and a third set value set to a predetermined value slightly larger than the output value of the angle sensor, and slightly smaller than the output value of the angle sensor corresponding to the minimum angle determined by the configuration of the first member and the second member. Comparing means having a fourth set value set to a predetermined value and comparing the detected value of the angle sensor with each of the set values; and output means outputting a failure signal in response to the result of this comparison. A failure detection device for an angle sensor, characterized in that it is provided with: