JPH04314939A - Controller for number of revolution of prime mover - Google Patents

Abstract

PURPOSE:To open-loop-control the number of revolution of an engine by detecting the out-of-step mode of a stepping motor and returning the stepping motor to a standard position. CONSTITUTION:Calculation is performed in the calculation part 25 of a controller 22, and the number of revolution of an engine 1 is open-loop-controlled, counting the number of pulses of the driving pulse signals outputted from an output part 24 by a counter 26, and the monitor value based on the counting value of the counter 26 and the detection value of a potentiometer 21 are compared, and the out-of-step mode of a stepping motor 6 is detected.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor rotational speed control device which is preferably installed in a construction machine such as a hydraulic excavator and used to control the rotational speed of a motor.

0002

2. Description of the Related Art Generally, construction machines are equipped with a diesel engine as a prime mover, and the diesel engine drives a hydraulic pump or the like.

[0003] For this reason, conventional construction machinery has a control lever installed in the driver's cab, and the control lever and the engine governor mechanism are connected with a control cable, link rod, etc. to control the engine rotation speed. . However, when mechanically connecting the control lever and the governor mechanism using a control cable, link rod, etc., there is a drawback that a large operating force is required due to large mechanical resistance.

[0004] In order to improve these drawbacks and remotely control the governor mechanism electrically, an electric motor is installed near the engine to drive the governor lever of the governor, and a fuel lever or up/down switch, etc. is installed in the driver's cab. and a controller consisting of a microcomputer or the like, the controller outputs a drive signal to the electric motor based on the command signal from the rotation speed command means,
A device is known in which a governor lever of a governor is rotated by an electric motor using open loop control.

[0005] FIG. 7 shows, as an example, a case where this type of prior art engine rotation speed control device is used in a construction machine.

In the figure, reference numeral 1 indicates a diesel engine (hereinafter referred to as "engine") as a prime mover mounted on a construction machine.
), 2 is a governor provided on the engine 1, and the governor 2 is provided with a governor lever 3, and stoppers 4 and 5 that come into contact with the governor lever 3 and restrict the rotation range of the governor lever 3, Move governor lever 3 to increase speed H and decelerate L
The rotational speed of the engine 1 is increased or decreased in accordance with the rotation in the direction. Then, in the governor 2, the governor lever 3 is moved to the stopper 4.
When it comes into contact with the stopper 5, the rotational speed of the engine 1 is set to the minimum rotational speed (idle rotational speed) or zero, and when it comes into contact with the stopper 5, the rotational speed of the engine 1 is set to the maximum rotational speed (full rotational speed).

Reference numeral 6 indicates a stepping motor as an electric motor for rotating the governor lever 3 of the governor 2. A rotating lever 6A is attached to the output shaft of the stepping motor 6, and the rotating lever 6A is connected to the rotating lever 6A via a link 7. and is connected to the governor lever 3. The stepping motor 6 is rotated forward and reverse by outputting a drive pulse signal from a controller 9, which will be described later, and rotates the governor lever 3 in the acceleration H and deceleration L directions via the link 7.

[0008] Reference numeral 8 indicates a command device which is installed in the operator's cab of the construction machine and serves as a rotation speed command means for commanding the rotation speed of the engine 1. A command signal corresponding to the amount is output to the controller 9.

[0009] Reference numeral 9 denotes a controller that is installed in the driver's cab or the like and is constituted by a microcomputer or the like. a calculation unit 12 that calculates a target rotation speed of the engine 1 based on the command signal given, and outputs a drive pulse signal as a drive signal from the output unit 11 to the stepping motor 6; and a drive pulse signal output from the output unit 11. and a counter 13 serving as a monitoring means for counting the number of pulses of The signal is output from the output section 11. Here, the calculation section 12 of the controller 9 constitutes a drive signal output means together with the output section 11, and rotates the stepping motor 6 with the drive pulse signal so that the rotation speed of the engine 1 becomes the target rotation speed. The rotation speed is controlled.

The conventional motor rotation speed control device has the above-described configuration, and when an operator outputs a desired rotation speed command from the command device 8 to the controller 9, the calculation section 12 of the controller 9 outputs a desired rotation speed command from the command device 8. The target rotational speed of the engine 1 is calculated based on the command signal from the engine 8, and the drive pulse signal is outputted from the output section 11 until the count value of the counter 13 becomes a value corresponding to the target rotational speed. By rotating the ping motor 6 in the forward and reverse directions, the governor lever 3 is rotated in the acceleration H and deceleration L directions, and open loop control is performed so that the rotation speed of the engine 1 becomes the target rotation speed corresponding to the command signal. .

[0011]

By the way, in the above-mentioned prior art, a drive pulse signal is output from the output section 11 of the controller 9 to the stepping motor 6, and the governor lever 3 of the governor 2 is rotated by the stepping motor 6. Since the rotation speed of the engine 1 is controlled by open-loop control, there is no need for a rotation angle detector to detect the rotation angle of the governor lever 3, etc., which has the advantage of simplifying the overall configuration. .

However, in the prior art, when the governor lever 3 collides with the stoppers 4 and 5, an overload is applied to the stepping motor 6 through the link 7, etc., so that the stepping motor 6 may suffer from so-called step-out. In this case, there is a problem in that it becomes difficult to control the rotation speed thereafter. In addition, the stepping motor 6
In the out-of-step mode, external noise enters the controller 9, the counter 13 is reset, and the arithmetic unit 12
In some cases, the rotational position of the stepping motor 6 cannot be determined due to a malfunction of the stepping motor 6, and in this case as well, control of the rotational speed becomes difficult as described above.

On the other hand, as another conventional technique, a potentiometer is provided as a rotation angle detector for detecting the rotation angle of a governor lever, etc., and the engine rotational speed is feedback-controlled based on a detection signal from the potentiometer. It has been known.

However, in this case, the potentiometer is exposed to vibrations from the engine, etc., so a certain amount of play is provided in the detection lever, etc. of the potentiometer to prevent the detection signal from the potentiometer from fluctuating due to external vibrations. This causes a problem in that the detection characteristics of the potentiometer deteriorates and it is difficult to feedback control the engine speed with high accuracy.

The present invention has been made in view of the problems of the prior art described above. When an electric motor such as a stepping motor enters a step-out mode, it can be detected early, and open loop control can be performed thereafter. The object of the present invention is to provide a rotational speed control device for a prime mover that can continue to operate and control the rotational speed with high precision.

[0016]

[Means for Solving the Problems] The features of the configuration adopted by the first invention in order to solve the above-mentioned problems include a rotation angle detection means for detecting the rotation angle of the electric motor, and a rotation angle detection means for detecting the rotation angle of the electric motor. The apparatus further comprises a determining means for comparing the rotation angle detection value from the means and a monitor value based on a signal from the monitoring means and determining whether or not the comparison value exceeds a predetermined value.

Further, the features of the configuration adopted by the second invention include: rotation angle detection means for detecting the rotation angle of the electric motor; rotation speed detection means for detecting the actual rotation speed of the prime mover; The present invention includes a determining means for comparing the actual rotational speed detection value from the detecting means and a monitor value based on a signal from the monitoring means and determining whether or not the comparison value exceeds a predetermined value.

In the first and second inventions, when the determination means determines that the comparison value exceeds a predetermined value, the electric motor is adjusted based on the rotation angle detection value from the rotation angle detection means. It is preferable that the electric motor is configured to include a correction signal output means for outputting a correction signal to return the electric motor to the reference position, and an operation selection means for selectively operating the correction signal output means and the drive signal output means. .

[0019]

[Operation] With the above configuration, in the first invention, the out-of-step mode of an electric motor such as a stepping motor can be detected at an early stage based on whether the comparison value between the rotation angle detection value and the monitor value exceeds a predetermined value. When the step-out mode is detected, for example, by returning the electric motor to the reference position, it becomes possible to drive the electric motor again from this reference position and perform open loop control again.

Further, in the second invention, the step-out mode of an electric motor such as a stepping motor can be detected early based on whether or not the comparison value between the actual rotation speed detection value and the monitor value exceeds a predetermined value. It becomes possible to continue open-loop control as in the invention of .

[0021]

Embodiments Hereinafter, embodiments of the present invention will be described with reference to FIGS. 1 to 6. In the embodiment, the same components as those of the prior art shown in FIG.

FIGS. 1 to 3 show a first embodiment of the present invention.

In the figure, reference numeral 21 denotes a potentiometer serving as rotation angle detection means for detecting the rotation angle of the stepping motor 6. The potentiometer 21 has a detection lever 21A, and the detection lever 21A is connected to the governor lever 3 and the stepping motor. It is connected in the middle of the link 7 between the rotating lever 6A of the link 6 and the rotating lever 6A of the link 7. The potentiometer 21 detects the rotation angle of the stepping motor 6 via the detection lever 21A, and outputs the detection signal to a controller 22, which will be described later, as a detected value Ek as a rotation angle detection value. .

Reference numeral 22 denotes a controller constituted by a microcomputer or the like, and the controller 22 has an input section 23 similar to the controller 9 described in the prior art.
, an output section 24, an arithmetic section 25, a counter 26, etc., the controller 22 converts the detection signal from the potentiometer 21 into a digital signal and outputs the detection value Ek.
An A-D converter 27 is attached which outputs the signal to the arithmetic unit 25 as a signal. The controller 22 includes a calculation unit 25
The program shown in FIG. 2 and the like are stored in the memory circuit of the engine 1 to perform rotation speed control processing, rotation speed correction processing, etc. of the engine 1.

Further, the calculation section 25 of the controller 22 stores the monitor value setting map illustrated in FIG. A reference value Ei as a reference position corresponding to the rotation angle of the stepping motor 6 when it rotates, a hysteresis value e as a predetermined value, etc. are stored, and the monitor value setting map is as shown in FIG. The monitor value Er that should correspond to the detected value Ek is set based on the count value C of . Then, the calculation section 25 of the controller 22
outputs a drive pulse signal from the output section 24 to the stepping motor 6 until this monitor value Er reaches a value corresponding to the target rotation speed, and when it reaches a value corresponding to the target rotation speed, outputs the drive pulse signal. Then, the rotating lever 6A of the stepping motor 6 is held at its rotating position.

Furthermore, a flag F as an operation selection means is stored in the storage area 25A.
=0, a drive pulse signal based on a command signal from the command device 8 is output from the output section 24 of the controller 22 to the stepping motor 6. and,
When the out-of-step mode of the stepping motor 6 is detected in step 6 of FIG. A corrected signal is output. Note that this flag F is always initially set as F=0 unless it is set as F=1 in step 8 of FIG.

The rotational speed control device for the engine 1 according to this embodiment has the above-described configuration.Next, the rotational speed correction processing of the engine 1 by the controller 22 will be described with reference to FIG.

First, when the processing operation starts, it is determined in step 1 whether or not the flag F is set to F=1. If the determination is "NO", the flag F is initially set as F=0. Then, proceeding to step 2, the number of pulses of the drive pulse signal outputted from the output section 24 to the stepping motor 6 based on the command signal from the command device 8 is calculated as follows.
Read as count value C from counter 26, step 3
Based on this count value C, the monitor value Er is read from the monitor value setting map shown in FIG.

Next, in step 4, the detected value Ek from the potentiometer 21 is read, and in step 5, a comparison value ΔE between this detected value Ek and the monitor value Er is calculated.

003
0]

[Equation 1] Calculate as ΔE=Ek −Er, move to step 6, determine whether the absolute value |ΔE| of this comparison value ΔE is within the range of a predetermined hysteresis value e, and select "YES". When the determination is made, the comparison value ΔE is substantially zero, and the detected value Ek corresponding to the rotation angle of the stepping motor 6 corresponds to the monitor value Er, so the stepping motor 6 does not go into step-out mode. , it can be determined that the drive state is normal, and the process moves to step 7 to return.

Further, when the determination in step 6 is "NO", the comparison value ΔE exceeds the range of the predetermined hysteresis value e and the stepping motor 6 is in the step-out mode, so the process moves to step 8 and flag F is set. F=1, and in step 9 it is determined whether the detected value Ek is equal to the reference value Ei corresponding to the idle rotation speed. If the determination is "YES", the rotation angle of the stepping motor 6 is equal to that of the engine 1. Since the reference rotation position corresponds to the idle rotation speed, the flag F is set to F=0 in step 10, the count value C of the counter 26 is cleared, and the process returns in step 7.

On the other hand, if the determination in step 9 is "NO", unless the stepping motor 6, which is in the out-of-step mode, is returned to the reference rotation position, the stepping motor 6 is opened by the drive pulse signal as in the case of the prior art. Since loop control becomes difficult, the process moves to step 11 to determine whether the detected value Ek is larger than the reference value Ei. If the determination is "YES", the stepping motor 6 is moved to the reference rotation position in step 12. A correction signal is output so as to reverse the direction toward the direction, and the process returns in step 7. Further, when the determination in step 11 is "NO", the process moves to step 13 and outputs a correction signal to rotate the stepping motor 6 in the normal direction toward the reference rotation position, and returns in step 7.

As long as the determination in step 9 is "NO", the processes from step 1 to steps 8 to 13 are repeated, and by continuing to output a correction signal to the stepping motor 6 in step 12 or step 13, ,
The stepping motor 6 is returned to the standard rotational position, and after performing steps 9, 10 and 7, a negative determination is made in step 1, and steps 2 to 7 are repeated.

Thus, according to this embodiment, the counter 2
It is possible to early detect whether or not the stepping motor 6 is in the step-out mode from the comparison value ΔE between the monitor value Er based on the count value C of 6 and the detected value Ek by the potentiometer 21, and when the step-out mode is detected, the stepping motor 6
can be returned to the reference rotational position corresponding to the idle rotational speed of the engine 1 by the correction signal, and it becomes possible to perform open-loop control of the stepping motor 6 again from this reference rotational position.

Therefore, in this embodiment, by detecting the out-of-step mode of the stepping motor 6 and forcibly returning the stepping motor 6 to the reference rotational position, open loop control can be continued thereafter, and the rotation of the engine 1 can be continued. The calculation can be performed with high precision without depending on the detection signal from the potentiometer 21. Further, by always returning the rotation speed of the engine 1 to the idle rotation speed when an out-of-step mode of the stepping motor 6 is detected, runaway of the engine 1, etc. can be effectively suppressed, and safety can be improved. .

Next, FIGS. 4 to 6 show a first embodiment of the present invention. In this embodiment, the same components as in the first embodiment are designated by the same reference numerals, and their explanations will be omitted. Therefore, the feature of this embodiment is that the engine 1 is provided with a crank angle sensor 31 as a rotation speed detection means for detecting the actual rotation speed, and the actual rotation speed detection is outputted from the crank angle sensor 31 to the controller 32. The present invention is configured to detect an out-of-step mode of the stepping motor 6 based on the actual rotational speed Nk as a value.

Here, the controller 32 is almost the same as the controller 22 described in the second embodiment.
3, output section 34, calculation section 35, counter 36 and A-
Although it is equipped with a D converter 37, the controller 32
is equipped with a converter 38 that converts the actual rotational speed signal from the crank angle sensor 31 into an actual rotational speed Nk that should correspond to a monitor rotational speed Nr to be described later. The arithmetic unit 35 of the controller 32 stores the program shown in FIG.

The storage circuit of the arithmetic unit 35 also stores a hysteresis value e, a reference value E i,
Flag F and monitor rotation speed setting map etc. are stored.
As shown in FIG. 6, this setting map is designed to set a monitor rotation speed Nr as a monitor value that should correspond to the actual rotation speed Nk of the engine 1 based on the count value C of the counter 36.

Next, the controller 32 controls the engine 1.
The rotation speed correction process will be explained with reference to FIG.
In steps 21 and 22, the same processing as steps 1 and 2 in FIG. 2 is performed, and in step 23, the count value C of the counter 36 is
Based on the setting map shown in Figure 6, monitor rotation speed Nr
In step 24, the actual rotational speed Nk is read, and in step 25, the comparison value ΔN between the actual rotational speed Nk and the monitor rotational speed Nr is calculated.

[0040]

[Equation 2] Calculate as ΔN=Nk −Nr, and in step 26, the absolute value of the comparison value ΔN |Δ
It is determined whether N| is within the range of a predetermined hysteresis value e, and if the determination is "YES", the stepping motor 6 is in a normal state, so the process returns to step 27.

Further, when the determination in step 26 is "NO", the stepping motor 6 is in the out-of-step mode, so the process moves to step 28 and sets the flag F to F=1, and in step 29 the output from the potentiometer 21 is The detected value Ek is read, and steps 30 to 34 are performed in the same manner as steps 9 to 13 in FIG.

[0042]Thus, this embodiment configured as described above can also obtain almost the same effects as the first embodiment, but in particular, in this embodiment, as shown in Equation 2, the actual rotational speed Nk Since the out-of-step mode of the stepping motor 6 is detected based on the comparison value ΔN between the monitor rotation speed Nr and the monitor rotation speed Nr, compared to the case where the detected value Ek from the potentiometer 21 is used as in the first embodiment, Out-of-step mode can be detected more accurately.

In each of the embodiments described above, step 6 (step 26) shown in FIG. ) shows a specific example of the correction signal output means, and steps 1, 8, 10 (steps 21, 28, 31)
shows a specific example of the operation selection means. Further, the calculation section 25 (35) of the controller 22 (32) is connected to the output section 24 (
34) constitutes a drive signal output means, and the counter 26
(36) constitutes a monitor means.

[0044]

As described in detail above, according to the present invention, the rotation angle detection value from the rotation angle detection means or the actual rotation speed detection value from the rotation speed detection means and the monitor value based on the signal from the monitor means Since it is determined whether or not this comparison value exceeds a predetermined value, it is possible to reliably detect the out-of-step mode of the electric motor based on this comparison value. By once returning to the reference position, open loop control becomes possible again, and the rotation speed of the prime mover can be controlled with high precision without feedback control.
It suppresses runaway of the prime mover and greatly improves safety.

[Brief explanation of the drawing]

FIG. 1 is an overall configuration diagram showing an engine rotation speed control device according to a first embodiment of the present invention.

FIG. 2 is a flow chart showing engine rotation speed correction processing according to the first embodiment.

FIG. 3 is an explanatory diagram of a monitor value setting map stored in a storage area of the controller.

FIG. 4 is an overall configuration diagram showing an engine rotation speed control device according to a second embodiment.

FIG. 5 is a flow chart showing engine rotation speed correction processing according to a second embodiment.

FIG. 6 is an explanatory diagram of a monitor rotation speed setting map stored in the storage area of the controller.

FIG. 7 is an overall configuration diagram showing an engine rotation speed control device according to the prior art.

[Explanation of symbols]

1 Engine (prime mover) 2 Governor 3 Governor lever 4, 5 Stopper 6 Stepping motor (electric motor) 7 Link 8 Command device (rotation speed command means) 21 Potentiometer (rotation angle detection means) 22, 3
2 Controller

Claims (4)

[Claims] 1. A prime mover, a governor attached to the prime mover that increases or decreases the rotation speed of the prime mover according to a rotation angle of a governor lever, an electric motor that rotates a governor lever of the governor, and a rotation speed of the prime mover. a rotation speed command means for commanding the rotation speed command means, a drive signal output means for outputting a drive signal to the electric motor based on a command signal from the rotation speed command means, and a monitor for monitoring the drive signal output from the drive signal output means. a rotation angle detection means for detecting a rotation angle of the electric motor; and a rotation angle detection value from the rotation angle detection means and a signal from the monitor means. 1. A rotational speed control device for a prime mover, comprising: determination means for comparing the comparison value with a monitor value based on the reference value and determining whether or not the comparison value exceeds a predetermined value. 2. When the determination means determines that the comparison value exceeds a predetermined value, a correction signal is output to the electric motor based on the rotation angle detection value from the rotation angle detection means, and the electric motor correction signal output means for returning the to the reference position;
2. The rotational speed control device for a prime mover according to claim 1, further comprising operation selection means for selectively operating said correction signal output means and said drive signal output means. 3. A prime mover, a governor attached to the prime mover that increases or decreases the rotation speed of the prime mover according to a rotation angle of a governor lever, an electric motor that rotates the governor lever of the governor, and a rotation speed of the prime mover. a rotation speed command means for commanding the rotation speed command means, a drive signal output means for outputting a drive signal to the electric motor based on a command signal from the rotation speed command means, and a monitor for monitoring the drive signal output from the drive signal output means. A rotation angle detection means for detecting a rotation angle of the electric motor; a rotation speed detection means for detecting an actual rotation speed of the prime mover;
and determining means for comparing the actual rotational speed detection value from the rotational speed detection means and a monitor value based on the signal from the monitoring means and determining whether or not the comparison value exceeds a predetermined value. Features a prime mover rotation speed control device. 4. When the determination means determines that the comparison value exceeds a predetermined value, a correction signal is output to the electric motor based on the rotation angle detection value from the rotation angle detection means, and the electric motor correction signal output means for returning the to the reference position;
4. The rotational speed control device for a prime mover according to claim 3, further comprising operation selection means for selectively operating said correction signal output means and said drive signal output means.