JPH10221115A - Stroke sensing cylinder load for reference-position detection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a stroke sensing cylinder load, for reference-position detection, which eliminates a displacement error which is generated in a stroke so as to be stored. SOLUTION: In a stroke sensing cylinder, a change in uneven parts 430 as magnetic graduations which are worked at a constant cycle on a cylinder load 400 is detected by a magnetic sensor, a signal is processed, and a displacement amount with reference to a stroke is detected. In the stroke sensing cylinder, the worked section of the magnetic graduations is firmed so as to contain one or more aperiodic unevenness worked parts, or the worked part of the magnetic graduations is formed in such a way that the position of the magnetic sensor is deviated from the worked position of the magnetic graduations in a state that the contraction of the expansion of the cylinder load is completed. Consequently, the cylinder load in which a reference position is designated can detect an errorless precise displacement amount and the reference position in the stroke of a hydraulic or pneumatic cylinder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder load of a stroke sensing cylinder. More specifically, excavators and fill roads (wheels)
hydraulic and pneumatic cylinders (hereinafter abbreviated as "cylinders") used for the automation of heavy construction equipment such as
The present invention relates to a reference position detecting stroke sensing cylinder load for enabling an accurate amount of displacement due to the stroke of the stroke to be understood.

[0002]

2. Description of the Related Art Generally, a cylinder for driving a working device such as a boom, an arm, and a bucket is mounted on a front device such as an excavator, and working oil is supplied or stored in the cylinder. The working device is driven by the cylinder performing a stroke operation by being discharged into a tank or the like.

However, in heavy construction equipment such as an excavator, the demand for a working device capable of accurately and repetitively performing a fixed work regardless of the skill level of a driver has increased with the development of electro-hydraulic servo control technology. It is getting. Therefore, the information on the position of the work equipment required by the control system for automation of the work equipment such as an excavator,
That is, it is desired to detect not only the partner position of the boom, the arm, and the bucket but also the absolute position.

As described in detail, as a means for detecting information on the position of the working device, a position detecting circuit for a cylinder stroke as shown in FIG. 1 and a cylinder stroke as shown in FIG. Only the position of the other party could be detected.

FIG. 1 is a schematic view of such a conventional oil / pneumatic cylinder, which is provided with a cylinder load on which magnetic scales are regularly machined. As shown in the drawing, the conventional hydraulic / pneumatic cylinder has a built-in piston 120 that can move up and down or left and right on the inner wall of the cylinder 110. One side of the piston 120 is a load supporting the movement of the piston 120. 130 is formed integrally with the piston 120.

On one side of the load 130, a plurality of magnetic graduations 140 are formed at predetermined intervals within a space between the top dead center and the bottom dead center of the piston 120. A magnetic sensor unit 150 for detecting a change in the magnetic field of the concave and convex portions of the magnetic scale 140 and performing an electrical signal processing on the load 130 at a predetermined distance from the point where the magnetic sensor unit is formed; In 150, a magnetic sensor 151 such as a hall sensor is
A pair (sensor A and sensor B) is mounted.

Here, the material of the cylinder load 130 is made of iron (Fe), and the portion where the magnetic scale 140 is processed is plated with chromium (Cr). When the generated magnetic field passes through the concave portion and the convex portion, the output of the magnetic sensor unit 150 becomes different, and actually forms a sinusoidal output waveform.

The interval between a pair of magnetic sensors is sufficiently larger than one cycle of the magnetic scale 140. The conventional cylinder 110 having the configuration as described in detail
When the zero reciprocates between the top dead center and the bottom dead center in the cylinder 110, the load 130 integrally mounted on the piston 120 moves, and the magnetic scale 140 formed on the load 130 moves. The state is detected by the magnetic sensor unit 150, and the stroke state of the cylinder 110 can be grasped.

That is, the magnetic scale detected by each magnetic sensor 151 of the magnetic sensor unit 150 when the piston 120 is initially stopped.
By ascertaining the number of magnetic scales 140 detected by the magnetic sensor 151 as the piston 120 moves from the position of 140, the movement distance of the piston 120 with respect to the number of magnetic scales 140 is calculated and the cylinder 11 is moved.
A stroke displacement of 0 can be grasped.

FIG. 2 is a block diagram showing an example of a circuit for detecting displacement of a cylinder stroke.

As shown, a cylinder driving unit 210 driven by an input cylinder driving signal is provided.
Drives the cylinder 220 on which the magnetic scale is machined,
The magnetic sensor unit 230 mounted on the cylinder 220 detects a change in the magnetic scale and applies an output signal from the microcomputer 240.

The microcomputer 240 exchanges necessary information with the internally stored or separately-stored storage device 250, and also exchanges signals with the 1 / N dividing counter 260 to start signal processing. To control the overall operation of the position detection circuit for the stroke of the cylinder.

The operation of the position detecting circuit for the stroke of the cylinder having the above-described structure is as follows. First, the cylinder driving unit 210 drives the cylinder 220 according to the input of the cylinder driving signal by the driver. At this time, the magnetic field generated by the cylinder (the magnetic scale machined on the load of the 220 (see FIG. 1 (140))). The change is detected by a set of magnetic sensors 231 such as a Hall sensor inside the magnetic sensor 230, and the detection signal is sent to the signal processing unit 23.
Apply at 2.

The signal processing section 232 generates a sine wave (sine w).
ave) Amplify and filter detection signals from a set of magnetic sensors 231 in a form
For example, the signal is converted into a signal recognizable by the microcomputer 240 and then output to the microcomputer 240. The microcomputer 240 converts the analog signal from the signal processing unit 232 into a digital signal using a built-in analog / digital converter, and then converts a signal of a sine wave form according to a predetermined algorithm into a set of signals. It is converted to a square-wave.

The 1 / N dividing counter 260 outputs a square wave (square-w) converted from the microcomputer 240.
ave), receives the input, divides the frequency by 1 / N, and outputs the result to the microcomputer 240. Using this, the microcomputer 240 calculates the displacement with respect to the stroke of the cylinder.

At this time, the reason why the detected pulse signal is divided by 1 / N is to increase the precision of detection by N times, and the N value is determined by the desired precision. The computer 240 counts the number of pulses that are N times the number of magnetic graduations processed on the cylinder load 130, calculates the displacement of the cylinder, and stores the value in the storage device 250.
To save.

At this time, the value stored in the storage device 250 may be output to a predetermined display (not shown). on the other hand,
The direction of movement of the cylinder is determined by comparing the phase of a set of generated rectangular waves. When the phase of the magnetic sensor B of the magnetic sensor unit 230 advances, the cylinder load in FIG. (Hereinafter referred to as "forward direction"), and when the phase of the magnetic sensor A advances, the cylinder load is transferred in a contracting direction (hereinafter referred to as "reverse direction").

FIG. 3 is a waveform diagram showing the principle of operation of the 1 / N dividing counter for signal processing when the displacement is detected by the circuit of FIG. If the cylinder moves in the reverse direction, four pulses are generated in one cycle according to the following equation (1), and if the cylinder load moves in the forward direction, the following equation (2) is used.

Here, A and B are rectangular waves converted corresponding to the sine waves detected by the sensors A and B, which are the magnetic sensors of the magnetic sensor unit 230, and A 'and B' are A's and B's.
And B are inverted signals. ΔA and ΔB are the one-shot (One-shot) in which A and B have a 1/4 frequency dividing counter.
shot) and a waveform generated after passing through a circuit (not shown), and ΔA ′ and ΔB ′ are inverted signals of ΔA and ΔB.

(Equation 1) (A × ＡB) + (B ′ × ´A) + (B × △ A ′) + (A
'× △ B') (Equation 2) (A × △ B ') + (B' × △ A ') + (B × △ A) +
(A '× △ B)

However, according to the conventional cylinder stroke position detecting device as described above,
By detecting the pulse generated by the magnetic graduation processed at regular intervals, it is possible to detect only the partner position, and it is not easy to detect the amount of displacement from the initial position of the cylinder load during work There was a problem.

As described above, when a displacement is detected by using a magnetic sensor, two sensors arranged so as to have a phase difference of 90 degrees are usually used for discriminating the direction and detecting the displacement. In such a case, it is not easy to accurately position the magnetic sensor so as to have a phase difference of 90 degrees due to a problem such as an assembly error.

Therefore, a displacement error may be generated. If such a displacement error is accumulated, not only the detection accuracy of the partner position is lowered, but also the direction of the cylinder stroke is changed. There was also.

In order to solve this problem, there have been cases where the magnetic strength of the magnetic scale is separately set or the magnetic scale for detecting the reference position is separately processed to perform position detection as a reference for displacement. However, it is not only difficult to precisely process such a magnetic scale, but it is difficult to accurately process a detected signal even if the magnetic scale is processed. However, there is a problem that another sensor unit must be added, because of the need to perform overlapping processing.

Therefore, an object of the present invention is to deform the magnetic scale to the cylinder load of the stroke sensing cylinder so that a predetermined reference position is made to correspond to the deformed processed portion, and the displacement amount is changed every time the stroke passes the reference position point. The present invention is to provide a stroke sensing cylinder load for reference position detection, which eliminates displacement errors generated during a stroke by replacing with a corresponding value.

[0025]

In order to achieve the above object, a feature of the stroke sensing cylinder load for detecting a reference position according to the present invention is to detect a change in the unevenness of a magnetic scale machined on the cylinder load at a constant period. In a stroke sensing cylinder that detects the amount of displacement relative to the stroke by detecting the signal with a sensor and processing the signal, the processing section of the magnetic scale may include one or more non-periodic irregularities, or the contraction and expansion of the cylinder load may be reduced. In the completed state, the magnetic scale processing portion is formed so that the position of the magnetic sensor deviates from the magnetic scale processing section.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of a stroke sensing cylinder load for detecting a reference position according to the present invention and the principle of detecting a reference position using the circuit of FIG. 2 will be described in detail with reference to FIGS. I do.

FIG. 4 is an external view schematically showing a reference position detecting stroke sensing cylinder load according to the present invention. The cylinder load 400 is made of iron (Fe).
And a concave / convex processing section 41 with a magnetic scale
0, 420, and 430 are plated with chromium (Cr).

Here, the processing section of the magnetic scale which has been processed to be uneven is formed so as to include one or more non-periodic uneven portions, and the non-periodic uneven portions are processed at a constant period. The period is machined longer than the set magnetic scale.

FIG. 5 is a cross-sectional view showing an example of an uneven processing section formed on the reference position detecting stroke sensing cylinder load according to the present invention. The magnetic graduations are formed one by one at a certain distance from both ends of the processing section of the magnetic graduation and separately from the magnetic graduation cycle.

FIG. 8 shows a case in which FIG. 5 is applied as the reference position detecting stroke cylinder load according to the present invention. In order to detect the reference position when the cylinder load moves in the contracting direction, the signal processing 1/4 frequency division is performed. FIG. 9 is a waveform diagram illustrating the operation principle of the circuit (see FIG. 2), and FIG. 9 is a waveform diagram illustrating a time when the cylinder load moves in the extending direction.

As shown in FIG. 3, FIG. 8 shows the case where the load of the cylinder moves in the contracting direction, that is, in the reverse direction, and the equation for receiving the desired signal is the mathematical formula described above. Equation 1 is as follows. When the stroke is performed in the reverse direction, the phase is counted based on the phase B. First, the phase B is checked while the phase B is at a low level while the phase B is checked.
When the phase is up-triggered, the point is recognized as a reference position. At this time, a more reliable reference point can be found by checking whether the number of pulses obtained from Equation 1 is one in one cycle of the B phase.

On the other hand, FIG. 9 shows the case in which the cylinder load moves in the direction in which the cylinder load extends, that is, in the forward direction. When a stroke is made in the forward direction, the phase is counted based on the phase A. During the inspection of the phase A, when the phase A is at a low level,
When a phase is up-triggered, that point is recognized as a reference point. At this time, it is possible to find a more reliable reference point by checking whether the number of pulses obtained from the above mathematical expression 1 is four in one cycle of the A phase.

FIG. 10 is a cross-sectional view showing another example of the uneven processing section formed in the stroke sensing cylinder load for detecting the reference position according to the present invention. Are formed so as to include one or more concave processing portions or convex processing portions.

FIG. 10 is a waveform diagram showing a principle of generating a rectangular wave when FIG. 10 is applied as a stroke sensing cylinder load for detecting a reference position according to the present invention.

In FIG. 10, (a) shows the magnetic scale of the cylinder load including the non-periodic uneven portion (440 in FIG. 10), and (b) and (c) show the sensor B and the sensor B by the movement of the cylinder load. A sine wave output from the sensor A is shown, and (d) and (e) show waveforms corresponding to (b) and (c), respectively, which are converted into rectangular waves, and the sensor B
When the waveform generated by the sensor A is normal, the phase difference is 90 degrees.

As shown in the drawing, after a detection signal for a non-periodic uneven portion (440 in FIG. 10) is input from a predetermined sensor with respect to the stroke of the cylinder, a further time is required for another one. When the detection signal of the non-periodic uneven portion by the sensor is input, the microcomputer 240 in FIG. 2 determines the reference position.

That is, when the two magnetic sensors (sensors A and B) detect the waveforms described in detail at predetermined time intervals, the displacement due to the stroke of the cylinder is reset (Reset), A fixed reference position value is specified for the displacement value.

FIG. 11 is a cross-sectional view showing still another example of the concavo-convex section formed in the stroke sensing cylinder load for reference position detection according to the present invention. Unlike FIG. 4 and FIG. 5 in which the contraction and expansion of the cylinder load are completed, the processed portion of the magnetic scale is formed so that the position of the magnetic sensor is out of the processed section of the magnetic scale.

As shown in the figure, the sensors A and B indicated by solid lines and the sensors A and B indicated by dotted lines deviate from the concavo-convex section when the cylinder load has been completely contracted and expanded. It shows the opponent's position.

FIG. 11 is a waveform diagram showing the principle of generating a rectangular wave when FIG. 11 is applied to the reference position detecting stroke sensing cylinder load according to the present invention.

In FIG. 11, (a) shows a magnetic scale of a cylinder load including a regular concave-convex processing section (430 in FIG. 10), and (b) and (c) show a sensor B and a sensor A by movement of the cylinder load. (D) and (e) respectively correspond to (b) and (c), and are generated by the sensor B and the sensor A as representing the waveforms converted into rectangular waves. When the waveform is normal, the phase difference is 90 degrees.

As shown in the drawing, after a sine wave is output from one of the sensors for the stroke of the cylinder, another sensor outputs a sine wave due to a change in the magnetic scale within a predetermined period of the magnetic scale. If not, the microcomputer 240 in FIG. 2 determines the reference position.

That is, if the two magnetic sensors (sensors A and B) do not simultaneously generate a regular magnetic scale detection waveform, the displacement due to the stroke of the cylinder is reset (Reset) or the displacement value at this time is kept constant. Will be specified.

[0044]

As described in detail, according to the stroke sensing cylinder load for detecting the reference position according to the present invention, the cylinder load of the present invention in which the reference position is designated can be used in the stroke of the hydraulic / pneumatic cylinder without any error. There is an effect that the displacement amount and the reference position can be detected.

[0045]

[Brief description of the drawings]

FIG. 1 is a schematic view of a conventional oil / pneumatic stroke sensing cylinder.

FIG. 2 is a block diagram showing an example of a cylinder stroke displacement detection circuit.

FIG. 3 shows a signal processing 1 /
FIG. 4 is a waveform chart showing the operation principle of the 分 frequency divider circuit.

FIG. 4 is an outline view schematically showing a reference position detecting stroke sensing cylinder load according to the present invention.

FIG. 5 is a cross-sectional view illustrating an example of a concavo-convex processing section formed on a stroke sensing cylinder load for reference position detection according to the present invention.

FIG. 6 is a cross-sectional view illustrating another example of a concavo-convex processing section formed on a reference position detecting stroke sensing cylinder load according to the present invention.

FIG. 7 is a cross-sectional view showing still another example of the concavo-convex processing section formed on the reference position detecting stroke sensing cylinder load according to the present invention.

FIG. 8 is a circuit diagram of a signal processing 1/4 frequency dividing circuit for detecting a reference position when the cylinder load moves in a contracting direction in the case where FIG. 7 is applied to the stroke sensing cylinder load for reference position detection according to the present invention; FIG. 4 is a waveform diagram illustrating an operation principle.

FIG. 9 is a circuit diagram of a signal processing 1/4 frequency dividing circuit for detecting a reference position when the cylinder load moves in a direction in which the cylinder load extends in a case where FIG. 5 is applied to the stroke sensing cylinder load for reference position detection according to the present invention. FIG. 4 is a waveform diagram illustrating an operation principle.

FIG. 10 is a waveform diagram illustrating a principle of generating a rectangular wave when FIG. 6 is applied to a stroke sensing cylinder load for reference position detection according to the present invention.

FIG. 11 is a waveform diagram illustrating a principle of generating a rectangular wave when FIG. 7 is applied to a reference position detecting stroke sensing cylinder load according to the present invention.

[Explanation of symbols]

400 Cylinder load 410, 420 Magnetic scale with long concave section 430 Magnetic scale with the same concave and convex intervals 440 Magnetic scale with long convex section

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Jin Han Lee South Korea Kwangsangnam-de-Changwon-City Sinchon-Dong Samsung Apartment 2-201 (72) Inventor San Taejan South Korea Kungsangnam-de-Changwon- City Shinwal-Dong 93 Euna Apartment 206-409 (72) Inventor Tae Jang Kim South Korea Kungsangnam-do Changwon-city Daebang-Dongsanwon Third Apartment 302-204 (72) Inventor Soon Yong Yang South Korea Kungsangnam -Do Chanwon-City Sapajung-Dongsanwon Apartment 206-405 Nam - de Cha N'won - City Dogae - Don family apartment 903 (72) inventor Ming Ceol of Wessex Lee Korea Busan Khumjung - click favorite phrase O - Don 166-1 Buyondakusan A part 101-506

Claims (5)

[Claims] In a stroke sensing cylinder, a magnetic sensor detects a change in unevenness of a magnetic scale machined on a cylinder load at a constant cycle by a magnetic sensor and detects a displacement amount with respect to a stroke by performing signal processing. A stroke sensing cylinder load for detecting a reference position, wherein the stroke sensing cylinder load is formed to include at least one part having a rough surface. 2. The method according to claim 1, wherein the non-periodic uneven portions are formed one by one at a predetermined distance from both ends of a magnetic scale processing section and independently of a magnetic scale period. 2. A stroke sensing cylinder load for detecting a reference position according to claim 1. 3. The stroke sensing cylinder load for detecting a reference position according to claim 1, wherein the non-periodic uneven portion is formed so as to include one or more concave portions or convex portions having different intervals. 4. The stroke sensing cylinder load for detecting a reference position according to claim 1, wherein the non-periodic uneven portion has a longer period than a magnetic scale processed at a constant period. . 5. A stroke sensing cylinder which detects an amount of displacement with respect to a stroke by detecting a change in unevenness of a magnetic scale machined on a cylinder load at regular intervals by a magnetic sensor and performing signal processing to complete the contraction and expansion of the cylinder load. A stroke sensing cylinder load for detecting a reference position, wherein a magnetic scale processing portion is formed so that the position of the magnetic sensor deviates from a magnetic scale processing section in a state where the magnetic sensor is set.