JPH06259140A - Sensor fault discriminating device for control mechanism - Google Patents

Abstract

PURPOSE:To effectively diagnose the fault of an electromotive force generation type sensor which detects the revolving frequency of a rotor, etc., even when the rotor is not rotated. CONSTITUTION:An electromotive force generation type sensor S is provided with a pair of output terminals 31 and 33. Then a controller 12 carries out a prescribed control operation based on the change information on the difference of potentials generated between both terminals 31 and 32 in response to the detecting action of the sensor S. In regard of a sensor fault discriminating device containing such a control mechanism, both terminals 31 and 32 of the sensor S are connected to the controller 12 via the wirings L1 and L2. A voltage detecting circuit 33 is set at the middle part between both wirings L1 and L2 to supply the same DC positive voltage to these wirings L1 and L2 and also ground one of both terminals 31 and 32 for detection of the voltage of the other terminal. Based on the voltage of the other terminal, it is discriminated whether the sensor S is faulty or not.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention detects the number of rotations of a rotating body such as a transmission shaft by counting the number of gear teeth by an electromagnetic induction type rotation number detection sensor, and based on the detected information,
More specifically, the present invention relates to a failure determination device for a detection sensor in a control mechanism that controls the flow rate of an engine-driven hydraulic drive device, and more particularly to a detection sensor that includes a pair of output terminals and is configured to generate electromotive force. The sensor failure determination device in the control mechanism configured so that the control device executes a predetermined control operation according to the change information of the potential difference generated between the output terminals in accordance with the detection operation.

[0002]

2. Description of the Related Art In a sensor failure determination device in the above control mechanism, conventionally, the failure diagnosis of the detection sensor is
The rotating device, which is the object to be detected, is actually rotated, the detection value of the detection sensor is read, and the control device is provided in advance with a failure diagnosis control program that determines whether or not the detection sensor is normal based on the detection result. The composition was considered.

[0003]

However, when the control mechanism as described above is adopted in an agricultural work vehicle or the like, and a rotating body which is an object to be detected by the detection sensor is driven by an engine. Needs to start the on-board engine and execute the failure diagnosis control. However, unlike the normal work control, such a fault diagnosis control operation is a special control mode, which may be dangerous if it is performed with the engine running. There is room for improvement because it requires a troublesome work such as connecting a dedicated inspection device directly to the output terminal of the sensor for inspection. The present invention aims to eliminate the above-mentioned problems.

[0004]

According to a characteristic configuration of the present invention, in the sensor failure determination device in the control mechanism described at the beginning, an output terminal of the detection sensor and an intermediate part of a wiring connecting the control device, The same DC positive voltage is supplied to each wiring, and one of the output terminals of the detection sensor is grounded, and a voltage detection means for detecting the voltage of the other output terminal is provided, and the voltage of the other output terminal. On the basis of the above, a sensor discriminating means for discriminating whether or not the detection sensor is abnormal is provided.

[0005]

[Effect] Even when the object to be detected is not driven and the detection electromotive force is not generated in the detection sensor, the DC positive voltage supplied to each output wiring detects from the output terminal on the side not grounded. A direct current is supplied to the output terminal on the ground side through the sensor. At this time, if the detection sensor is normal, the output terminal on the non-grounded side has a voltage level higher than the ground voltage by the internal impedance of the detection sensor. Then, this voltage is detected by the voltage detecting means, and the sensor determining means can determine that the voltage is normal. Further, if the detection sensor has a disconnection failure, the DC positive voltage is detected as it is in the voltage detection means, so it can be determined that there is a failure, and if the detection sensor has a short circuit failure, the voltage detection means does not. The same potential as that of the output terminal on the other side, that is, the ground voltage is detected, and it can be determined that there is a failure.
Although a voltage different from the detection information is supplied to the output circuit of the detection sensor, since the detection sensor is an electromotive force generation type, it is configured to detect only the change in the potential difference between the output terminals. No support.

[0006]

Therefore, even when the detection sensor is used for detecting the rotational driving state of a large-sized apparatus, a troublesome work such as setting the large-sized apparatus into a dangerous state such as actually rotating the apparatus is performed. It is now possible to safely diagnose the failure of the detection sensor without requiring

[0007]

Embodiments will be described below with reference to the drawings. Figure 4
As shown in FIG. 2, a cultivating device 4 [an example of a working device] is provided at the rear part of the riding type traveling body so that it can be freely moved up and down and left and right via a link mechanism 3 including a top link 1 and a pair of left and right lower links 2 and 2. To form a riding-type cultivator. The tip ends of a pair of lift arms 6 that swing up and down by a lift cylinder 5 and the lower links 2,
2 and 2 are linked via lift rods 7, 7, the tilling device 4 is configured to be movable up and down by the lift cylinder 5, and one lift rod 7 is connected to the rolling cylinder 8
Is provided so as to be freely extendable and contractible, and the expanding and contracting operation of the rolling cylinder 8 causes the tilling device 4 to perform left and right rolling operations with respect to the traveling machine body. As shown in FIG. 1, this tiller is provided with a potentiometer-type tillage depth sensor 10 for detecting the amount of up-and-down swing of a rear cover 9 which is provided at the tiller 4 so as to be able to swing up and down.
The control device 12 equipped with a microcomputer switches the electromagnetic hydraulic control valve 13 to the lift cylinder 5 so that the detected value of 0 is maintained at the set plowing depth by the potentiometer type plowing depth setting device 11 provided in the aircraft control section. The stroke sensor 14 configured to control the tilling depth is provided, and the stroke sensor 14 for detecting the expansion and contraction operation amount of the rolling cylinder 8 is provided, and the weight type inclination sensor 15 for detecting the lateral inclination of the traveling machine body is provided. The potentiometer-type rolling setter 16 provided in the control section is used while judging the relative inclination of the tiller 4 with respect to the airframe from the output of
The stroke sensor 14
The electromagnetic hydraulic control valve 17 for the rolling cylinder 8 is controlled to be switched on the basis of the feedback value of 1. Also, the lift arm 6
A lift arm angle sensor 18 for detecting an elevation angle with respect to the aircraft is provided on the rotation pivot support part of the control unit 12 so that the detection value of the lift arm angle sensor 18 is maintained at the set value of the potentiometer-type position setter 19. The electromagnetic hydraulic control valve 13 for the lift cylinder 5 is configured to be switched and controlled to perform position control. In addition, the tiller 4
Position is used to increase the
When the level set by the position setter becomes low enough to reach the ground contact lowering state, the operation is switched to the tilling depth control operation.

The airframe control section is provided with a three-position changeover changeover switch 20 capable of manually driving the tilling device 4 to roll, in preference to the above-described automatic rolling control operation. The change-over switch 20 is biased to return to the neutral position, and the control device 12 is operated by manually operating to either the upward-rightward operation position "" or the upward-leftward operation position "" against the neutral biasing force. The electromagnetic control valve 17 for the rolling cylinder is switched in preference to the automatic rolling control operation. When the switch 20 is released, it is automatically returned to the neutral position by the restoring force.

The engine E mounted on the traveling machine body
Equipped with an engine speed detection sensor S for detecting the output speed of the engine, the engine load is judged from the amount of decrease in the speed of rotation while sequentially reading changes in the speed of the engine E during tilling work. When
For example, the control parameter is configured to be corrected, for example, by correcting the set cultivation depth in the cultivation depth control to be shallow. As shown in FIG. 3, the rotation speed detection sensor S includes an engine E
Is arranged in the vicinity of the starter motor driving gear portion 28 formed on the flywheel, and is configured to be a power generation type based on electromagnetic induction in which a coil is wound around a magnet, and a potential difference generated between both output terminals of the coil is compared by a comparator 29. Detected by
The detection circuit is configured so that the controller 12 receives a pulse output signal of about 5 volts. Then, the same DC positive voltage [5 volts] is applied to the wirings L1 and L2 via pull-up resistors R and R in the middle of the wirings L1 and L2 connecting the output terminals 31 and 32 of the sensor and the comparator 29. And a voltage detection circuit 33 (an example of voltage detection means) for grounding one of the output terminals 31 of the detection sensor S and detecting the voltage of the other output terminal 32. The control device 12 is provided with a sensor discriminating means A for discriminating whether or not the detection sensor S is abnormal based on the voltage of the terminal 32 in a control program format.

When the main switch 21 for the control device 12 is turned on and operated while the manual rolling changeover switch 20 is in an operation position and is operated,
It is equipped with a mode switching means B for automatically switching between an output adjustment mode for adjusting the output value of each potentiometer type sensor or each setting device, or a self-diagnosis mode for performing a failure diagnosis of each sensor, and the sensor discrimination The means A is arranged to operate in this self-test mode. More specifically, the mode switching means B is provided in the control device 12 in the form of a control program, and the control device 12 executes control as follows. As a premise for performing such output adjustment control, the traveling machine body is in a horizontal posture, the tiller 4 is raised to the maximum raised position, and the tiller 4 is
The condition is that the robot is in a parallel attitude to the aircraft. Therefore, the position setter 19 is at the maximum raised position, and the rolling setter 16 is set at the horizontal position.
Both the main switch 21 and the changeover switch 20 are arranged on the right side of the control panel 22 of the machine body, and when the operator is seated on the driver's seat 23 on the machine body, the control handle 25 interferes so that both hands cannot be operated simultaneously. . Therefore,
The simultaneous operation of the switches 20 and 21 as described above is performed without getting off the aircraft and starting the engine E from the lateral outside of the aircraft. As shown in FIG. 2, when the main switch 21 is turned on and operated, if the changeover switch 20 is maintained at the neutral position at that time, each of the above-described automatic plowing depth control, automatic rolling control and position control is performed. The control mode is set to the working control mode (steps 1 to 3). If the changeover switch 20 is operated to the operation position "" when the main switch 21 is turned on, the output adjustment mode is set [step 4]. If the operation position is "", the self-diagnosis mode is set [step 5]. When the output adjustment mode is set, when the changeover switch 20 is once returned to the neutral position and then again changed to the operation position "", the outputs of the sensors and the adjusters are output in a predetermined order. Read in order with
The data is written and stored in a non-volatile memory that is electrically writable and erasable, and the stored value is used as a control reference value for each work control as described above. Then, when the main switch 21 is turned off and the main switch 21 is turned on again, the operation control mode described above is entered [step 6]. In the self-diagnosis mode, as soon as the self-diagnosis mode is set, the output of each sensor or the like is read to diagnose whether or not disconnection or short circuit has occurred [step 7]. At this time, for the rotation speed detection sensor S, the output voltage of the output terminal 32 is read through the voltage detection circuit 33, and this voltage V is about 0.
If the voltage is 5 volts or about 5 volts, it can be determined that the coil of the detection sensor S has a disconnection failure or a short circuit failure. At this time, the indicator lamp 27 provided on the control panel 22 detects this. The display is blinked the number of times corresponding to the part number of the sensor S [steps 8 to 10]. Then, if there is an abnormality after the output determination of other sensors is completed,
The display lamps 27 are blinked and displayed for each sensor the number of times corresponding to the part number previously displayed, the operator is informed of which sensor is in failure, and if there is no abnormality, the display lamps 27 are continuously lit [steps 11 to 14]. ]. Then, when the main switch 21 is turned off and the main switch 21 is turned on again, the operation control mode described above is entered [step 15].

It should be noted that reference numerals are added to the claims to facilitate the comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a control block diagram.

[Fig. 2] Control flowchart

[Fig. 3] Electric circuit diagram for failure determination

FIG. 4 is a perspective view of the rear part of the cultivator.

[Explanation of symbols]

 12 control device 31, 32 output terminal 33 voltage detection means A sensor determination means L1, L2 wiring S detection sensor

Claims (1)

[Claims] 1. A detection sensor (S) having a pair of output terminals (31) and (32) and configured to generate electromotive force. The both outputs are accompanied by a detection operation of the detection sensor (S). A sensor failure determination device in a control mechanism configured to cause a control device (12) to perform a predetermined control operation according to change information of a potential difference generated between terminals (31) and (32). Each output terminal (3) of (S)
1), (32) and the control device (12), the wirings (L1), (L2) are connected in the middle of the wirings (L1), (L2).
Voltage detecting means for supplying the same DC positive voltage to (L2), grounding one of the output terminals (32) of the detection sensor (S), and detecting the voltage of the other output terminal (32). (33), and the other output terminal (3
A sensor failure determination device in a control mechanism, which is provided with a sensor determination means (A) that determines whether or not the detection sensor (S) is abnormal based on the voltage of 2).