Absolute position detection device of electric cylinder, control method thereof, and electric cylinder

Abstract

The present invention provides an absolute position detection device for an electric cylinder, a control method thereof, and an electric cylinder. The detection device comprises: multiple gears, each having a different number of teeth and each containing a magnet; multiple encoders for detecting the positions of the magnets; and a microcontroller unit for fitting a curve based on the positions of the magnets, which represents the maximum absolute difference between the magnets and the absolute position of the electric cylinder. When the microcontroller unit is powered off and then powered back on, the maximum absolute difference between the magnets is calculated, and the absolute position of the electric cylinder is determined based on the calculated maximum absolute difference between the magnets and the curve after power is restored. This device can accurately detect the position of the electric cylinder when the microcontroller unit is powered off, without requiring the installation of an additional power supply module, thereby improving the reliability of the electric cylinder.

Description

Technical Field

[0001] The present invention relates to the technical field of industrial control, and in particular to an absolute position detection device for an electric cylinder, a control method for the absolute position detection device for the electric cylinder, and the electric cylinder. Background Art

[0002] An electric cylinder is an electrically driven device that converts the rotational motion of a motor into linear motion of a push rod. It is widely used in industries such as machinery, metallurgy, mining, transportation, and construction. In practical applications, the controller needs to obtain the position of the electric cylinder to achieve relevant control.

[0003] Currently, the position of electric cylinders on the market is generally recorded by Hall sensors. When the controller loses power, only the position of the electric cylinder immediately before the controller loses power can be recorded. If the position of the electric cylinder shifts after the controller loses power, since the Hall sensor can only record the position of the electric cylinder motor for one circle, if the position shift exceeds one circle, the relevant controller will not be able to know the true position of the electric cylinder.

[0004] In the related art, although a button battery is added to the control board to ensure that the controller does not lose power, the battery power is limited, so this method is not reliable enough. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides an absolute position detection device for an electric cylinder.

[0006] The present invention also provides a control method for the absolute position detection device of the electric cylinder.

[0007] The present invention also provides an electric cylinder.

[0008] The technical solution adopted in the present invention is as follows:

[0009] The first aspect of the present invention provides an absolute position detection device for an electric cylinder, comprising: a plurality of gears, each of which is respectively connected to the motor of the electric cylinder, the plurality of gears being superimposed and meshing with each other, and each of the gears having a different number of teeth, each of the gears containing a magnet, and the magnet being a polar axial magnet; a plurality of encoders, each of which is respectively connected to a corresponding gear, and the encoders being used to respectively detect the positions of the magnets; a microcontroller unit, the microcontroller unit being connected to the encoders, the microcontroller unit being used to fit a curve of the maximum absolute difference in position between the magnets and the absolute position of the electric cylinder according to the position of the magnets, calculating the maximum absolute difference in position between the magnets when the microcontroller unit is powered off and powered on again, and obtaining the absolute position of the electric cylinder based on the maximum absolute difference in position between the magnets and the curve calculated when the power is re-on.

[0010] The absolute position detection device for the electric cylinder proposed in the present invention also has the following additional technical features:

[0011] According to one embodiment of the present invention, the gear includes: a first gear and a second gear, the first gear and the second gear are connected to the motor of the electric cylinder, the first gear contains a first magnet, and the second gear contains a second magnet; the encoder includes: a first encoder and a second encoder, the first encoder and the second encoder are respectively connected to the first gear and the second gear, and the first encoder and the second encoder are used to detect the position of the first magnet and the second magnet, respectively.

[0012] According to one embodiment of the present invention, the microcontroller unit is specifically used to: calculate the maximum absolute difference in the positions of the magnets when the electric cylinder is first powered on, so as to obtain the maximum absolute difference in the positions of the magnets at the zero position of the electric cylinder; calculate the maximum absolute difference in the positions of the magnets after controlling the forward and reverse rotation of the electric cylinder motor for a preset number of turns, so as to obtain the maximum absolute difference in the positions of the magnets at the maximum stroke of the electric cylinder; and fit a curve of the maximum absolute difference in the positions of the magnets and the absolute position of the electric cylinder based on the maximum absolute difference in the positions of the magnets at the zero position and the maximum absolute difference in the positions of the magnets at the maximum stroke.

[0013] According to one embodiment of the present invention, the difference in the number of teeth between the first gear and the second gear is 2.

[0014] According to one embodiment of the present invention, the number of teeth of the first gear is 68 and the number of teeth of the second gear is 70.

[0015] According to one embodiment of the present invention, the first encoder and the encoder are arranged on a circuit board where the micro control unit is located.

[0016] A second aspect of the present invention provides a method for controlling an absolute position detection device for an electric cylinder, comprising the following steps: obtaining the position of each magnet detected by the encoder respectively; fitting a curve of the maximum absolute difference in position between the magnets and the absolute position of the electric cylinder according to the position of each magnet; calculating the maximum absolute difference in position between the magnets when power is off and on again; and obtaining the absolute position of the electric cylinder based on the maximum absolute difference in position between the magnets calculated when power is on again and the curve.

[0017] The control method of the absolute position detection device of the electric cylinder of the present invention also has the following additional technical features:

[0018] According to one embodiment of the present invention, fitting a curve between the maximum absolute difference between the positions of the magnets and the absolute position of the electric cylinder based on the position of each magnet specifically includes: calculating the maximum absolute difference between the positions of the magnets when the electric cylinder is initially powered on to obtain the maximum absolute difference between the positions of the magnets at the zero position of the electric cylinder; calculating the maximum absolute difference between the positions of the magnets after controlling the forward and reverse rotation of the electric cylinder motor for a preset number of revolutions to obtain the maximum absolute difference between the positions of the magnets at the maximum stroke of the electric cylinder; and fitting a curve between the maximum absolute difference between the positions of the magnets and the absolute position of the electric cylinder based on the maximum absolute difference between the positions of the magnets at the zero position and the maximum absolute difference between the positions of the magnets at the maximum stroke.

[0019] A third embodiment of the present invention provides an electric cylinder, which includes the absolute position detection device of the electric cylinder described in the first embodiment of the present invention.

[0020] The present invention has the following beneficial effects:

[0021] The present invention can accurately detect the position of the electric cylinder when the microcontroller unit loses power, and does not require additional installation of a power supply module, thereby improving the reliability of the operation of the electric cylinder. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is a block diagram of an absolute position detection device for an electric cylinder according to one embodiment of the present invention;

[0023] Figure 2 4 is a flow chart of a control method of an absolute position detection device for an electric cylinder according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] The following describes an absolute position detection device for an electric cylinder, a control method thereof, and an electric cylinder provided in embodiments of the present invention with reference to the accompanying drawings.

[0026] Figure 1 FIG. 1 is a block diagram of an absolute position detection device for an electric cylinder according to an embodiment of the present invention. Figure 1 As shown, the device includes: multiple gears, multiple encoders and a micro control unit 5, wherein Figure 1In the example, two gears (a first gear 1 and a second gear 2) and two encoders (a first encoder 3 and a second encoder 4) are used.

[0027] Each gear is connected to the motor of the electric cylinder respectively, and the multiple gears are superimposed and meshed with each other, and each gear has a different number of teeth. Each gear contains a magnet, which is a polar axial magnet; each encoder is connected to a corresponding gear, and the encoder is used to detect the position of the magnet respectively; the micro control unit 5 is connected to the encoder, and the micro control unit 5 is used to fit the curve of the maximum absolute difference between the positions of the magnets and the absolute position of the electric cylinder according to the position of the magnets, calculate the maximum absolute difference between the positions of the magnets when the micro control unit is powered off and then powered on again, and obtain the absolute position of the electric cylinder based on the maximum absolute difference between the positions of the magnets and the curve calculated when the power is restored.

[0028] Specifically, the encoder can detect the current state of the magnet, and as the magnet rotates, the encoder can obtain a 360° rotational position. The microcontroller unit 5 pre-fits the relationship curve between the maximum absolute difference in the positions of the magnets and the absolute position of the electric cylinder based on the maximum absolute difference in the positions of the magnets. When power is cut off at any position and then re-powered on, the microcontroller unit 5 calculates the absolute difference in the positions of the two magnets by reading the position of the magnets when the power is re-on, and obtains the maximum absolute difference. The absolute position of the electric cylinder can be obtained based on the maximum absolute difference in the positions of the magnets calculated after the power is re-on and the above curve. Thus, the device can accurately detect the position of the electric cylinder when the microcontroller unit loses power, and there is no need to install an additional power supply module, thereby improving the reliability of the electric cylinder.

[0029] In a specific embodiment of the present invention, Figure 1 As shown, the gears may include: a first gear 1 and a second gear 2, and the encoders may include: a first encoder 3 and a second encoder 4. The first gear 1 and the second gear 2 are connected to the motor of the electric cylinder, meshing with each other, and having different numbers of teeth. The first gear 1 contains a first magnet, and the second gear 2 contains a second magnet, and the first magnet and the second magnet are polar axial magnets. The first encoder 3 and the second encoder 4 are connected to the first gear 1 and the second gear 2, respectively, and are used to detect the position of the first magnet and the second magnet, respectively. The microcontroller unit 5 is connected to the first encoder 3 and the second encoder 4, and is used to fit a curve between the absolute difference between the positions of the first magnet and the second magnet and the absolute position of the electric cylinder based on the positions of the first magnet and the second magnet. When the microcontroller unit 5 is powered off and then powered on again, the absolute difference between the positions of the first magnet and the second magnet is calculated, and the absolute position of the electric cylinder is obtained based on the absolute difference between the positions of the first magnet and the second magnet and the curve calculated after the power is turned on again.

[0030] Specifically, the first encoder 3 and the second encoder 4 respectively detect the current states of the first and second magnets. As the magnets rotate, the encoders can obtain a 360° rotational position. The microcontroller unit 5 pre-fits a relationship curve between the absolute difference between the positions of the two magnets and the absolute position of the electric cylinder based on the positions of the first and second magnets. When power is lost at any position and then restored to power, the microcontroller unit 5 reads the absolute difference between the positions of the first and second magnets at the time of restoration, and the absolute difference between the positions of the two magnets calculated upon restoration and the aforementioned curve can be used to obtain the absolute position of the electric cylinder. Thus, the device can accurately detect the position of the electric cylinder when the microcontroller unit loses power, without the need for an additional power supply module, thereby improving the reliability of the electric cylinder.

[0031] During the power-on process, the micro control unit 5 can also obtain the absolute position of the electric cylinder in real time according to the absolute difference between the positions of the two magnetic steels and the above curve.

[0032] According to one embodiment of the present invention, the microcontroller unit 5 is specifically configured to: calculate the maximum absolute difference in the positions of the magnets when the electric cylinder is initially powered on, so as to obtain the maximum absolute difference in the positions of the magnets at the zero position of the electric cylinder; calculate the maximum absolute difference in the positions of the magnets after controlling the forward and reverse rotation of the electric cylinder motor for a preset number of turns, so as to obtain the maximum absolute difference in the positions of the magnets at the maximum stroke of the electric cylinder; and fit a curve of the maximum absolute difference in the positions of the magnets and the absolute position of the electric cylinder based on the maximum absolute difference in the positions of the magnets at the zero position and the maximum absolute difference in the positions of the magnets at the maximum stroke.

[0033] Specifically, when the electric cylinder is powered on for the first time, the absolute difference in the position between each pair of magnets is calculated to obtain the maximum absolute difference at the zero position of the electric cylinder. Then, the maximum absolute difference in the position between each pair of magnets at the maximum stroke of the electric cylinder is obtained. Thus, a curve of the maximum absolute difference between the position of the electric cylinder and the position of the magnets can be fitted based on the coordinates of these two points.

[0034] After obtaining the maximum absolute difference between the magnet positions at the electric cylinder's zero point, you can also record the maximum absolute difference between the two magnet positions and the absolute position of the electric cylinder by controlling the motor's forward and reverse rotation for verification. After verification, run the motor and record the maximum absolute difference between the magnet positions at maximum travel.

[0035] for Figure 1The middle gear includes two detection devices and the encoder includes two detection devices. When the electric cylinder is first powered on, the absolute difference between the positions of the first magnet and the second magnet is calculated to obtain the absolute difference between the positions of the first magnet and the second magnet at the zero position of the electric cylinder; the absolute difference between the positions of the first magnet and the second magnet is calculated after controlling the forward and reverse rotation of the electric cylinder motor for a preset number of turns to obtain the absolute difference between the positions of the first magnet and the second magnet at the maximum stroke of the electric cylinder; according to the absolute difference between the positions of the first magnet and the second magnet at the zero position and the absolute difference between the positions of the first magnet and the second magnet at the maximum stroke, a curve of the absolute difference between the positions of the first magnet and the second magnet and the absolute position of the electric cylinder is fitted.

[0036] In a specific embodiment of the present invention, the difference in the number of teeth between the first gear 1 and the second gear 2 may be 2. For example, the number of teeth of the first gear is 68 and the number of teeth of the second gear is 70.

[0037] In one embodiment of the present invention, the first encoder 3 and the second encoder 4 may be arranged on a circuit board where the micro control unit 5 is located.

[0038] In summary, according to the absolute position detection device for an electric cylinder according to the embodiment of the present invention, a curve is pre-fitted to the relationship between the maximum absolute difference between the positions of the magnets and the absolute position of the electric cylinder based on the maximum absolute difference between the positions of the magnets. When power is lost at any position and then restored, the microcontroller reads the positions of the magnets at the time of restoration, calculates the absolute differences between the positions of each pair of magnets, and obtains the maximum absolute difference. The absolute position of the electric cylinder can be determined based on the maximum absolute difference between the positions of the magnets calculated upon restoration and the curve. Thus, the device can accurately detect the position of the electric cylinder when the microcontroller loses power, without requiring the installation of an additional power supply module, thereby improving the reliability of the electric cylinder.

[0039] Based on the above-mentioned absolute position detection device for an electric cylinder, the present invention further provides a control method for the absolute position detection device for an electric cylinder.

[0040] Figure 2 FIG. 1 is a flow chart of a control method of an absolute position detection device for an electric cylinder according to an embodiment of the present invention. Figure 2 As shown, the method includes the following steps:

[0041] S1, respectively obtain the position of each magnetic steel detected by the encoder.

[0042] S2, based on the position of each magnet, fit the curve of the maximum absolute difference between the positions of the magnets and the absolute position of the electric cylinder.

[0043] S3, calculates the maximum absolute difference in position between the magnets when power is off and then on again.

[0044] S4, obtaining the absolute position of the electric cylinder according to the maximum absolute difference between the positions of the magnetic steels calculated after power-on and the curve.

[0045] According to one embodiment of the present invention, fitting a curve of the maximum absolute difference in positions between the magnets and the absolute position of the electric cylinder based on the position of each magnet specifically includes: calculating the maximum absolute difference in positions between the magnets when the electric cylinder is first powered on to obtain the maximum absolute difference in positions between the magnets at the zero position of the electric cylinder; calculating the maximum absolute difference in positions between the magnets after controlling the forward and reverse rotation of the electric cylinder motor for a preset number of turns to obtain the maximum absolute difference in positions between the magnets at the maximum stroke of the electric cylinder; fitting a curve of the maximum absolute difference in positions between the magnets and the absolute position of the electric cylinder based on the maximum absolute difference in positions between the magnets at the zero position and the maximum absolute difference in positions between the magnets at the maximum stroke.

[0046] In summary, according to the control method for an absolute position detection device for an electric cylinder according to an embodiment of the present invention, a curve is pre-fitted based on the maximum absolute difference between the positions of the magnets and the absolute position of the electric cylinder. When power is lost at any position and then restored, the position of the magnets at the time of restoration is read to calculate the absolute differences between the positions of each pair of magnets, obtaining the maximum absolute difference. The absolute position of the electric cylinder can be determined based on the maximum absolute difference between the positions of the magnets calculated upon restoration and the curve. This allows accurate detection of the position of the electric cylinder when the microcontroller loses power, without requiring the installation of an additional power supply module, and thus improves the reliability of the electric cylinder.

[0047] In addition, the present invention also provides an electric cylinder, which includes the absolute position detection device of the electric cylinder described above.

[0048] In the description of the present invention, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, a feature specified as "first" or "second" may explicitly or implicitly include one or more of such features. "Multiple" means two or more, unless otherwise specifically defined.

[0049] In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connect," "fixed," etc. should be understood broadly. For example, they may refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0050] In the description of this specification, the reference terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and features of different embodiments or examples without contradiction.

[0051] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, segment or portion of code comprising one or more executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present invention includes alternative implementations in which functions may be performed out of the order shown or discussed, including performing functions in a substantially simultaneous manner or in the reverse order depending on the functions involved, which should be understood by those skilled in the art to which the embodiments of the present invention pertain.

[0052] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device. More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic device), random access memory (RAM), read-only memory (ROM), erasable and programmable read-only memory (EPROM or flash memory), fiber optic devices, and a portable compact disc read-only memory (CDROM). Furthermore, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium and then editing, interpreting or processing it in another suitable manner if necessary, and then storing it in a computer memory.

[0053] It should be understood that various parts of the present invention can be implemented using hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods can be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one of the following technologies known in the art or a combination thereof can be used: a discrete logic circuit having a logic gate circuit for implementing a logic function on a data signal, an application-specific integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0054] Those skilled in the art will understand that all or part of the steps in the method of the above embodiment can be completed by instructing related hardware through a program, and the program can be stored in a computer-readable storage medium. When the program is executed, it includes one or a combination of the steps of the method embodiment.

[0055] In addition, the functional units in the various embodiments of the present invention may be integrated into a single processing module, or each unit may exist physically separately, or two or more units may be integrated into a single module. The aforementioned integrated modules may be implemented in the form of hardware or in the form of software functional modules. If the integrated modules are implemented in the form of software functional modules and sold or used as independent products, they may also be stored in a computer-readable storage medium.

[0056] The storage medium mentioned above may be a read-only memory, a magnetic disk, or an optical disk, etc. Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and are not to be construed as limiting the present invention. Persons skilled in the art may make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

[0057] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An absolute position detection device for an electric cylinder, characterized in that: include: A plurality of gears, each of which is connected to the motor of the electric cylinder, the plurality of gears are superimposed and meshed with each other, and each of the gears has a different number of teeth, and each of the gears contains a magnet, which is a polar axial magnet; A plurality of encoders, each encoder being connected to a corresponding gear, and the encoders being used to detect the position of the magnetic steel respectively; a microcontrol unit connected to the encoder, configured to fit a curve of a maximum absolute difference between the positions of the magnetic steels and the absolute position of the electric cylinder according to the positions of the magnetic steels, calculate the maximum absolute difference between the positions of the magnetic steels when the microcontrol unit is powered off and then powered on again, and obtain the absolute position of the electric cylinder based on the maximum absolute difference between the positions of the magnetic steels calculated when the power is turned on again and the curve; The micro control unit is specifically used for: Calculating the maximum absolute difference between the positions of the magnetic steels when the electric cylinder is powered on for the first time to obtain the maximum absolute difference between the positions of the magnetic steels at the zero position of the electric cylinder; The maximum absolute difference between the positions of the magnetic steels is calculated by controlling the forward and reverse rotation of the electric cylinder motor for a preset number of turns, so as to obtain the maximum absolute difference between the positions of the magnetic steels at the maximum stroke of the electric cylinder; According to the maximum absolute difference between the positions of the magnetic steels at the zero position and the maximum absolute difference between the positions of the magnetic steels at the maximum stroke, a curve of the maximum absolute difference between the positions of the magnetic steels and the absolute position of the electric cylinder is fitted.

2. The absolute position detection device of the electric cylinder according to claim 1, characterized in that: The gears include: a first gear and a second gear, the first gear and the second gear are connected to the motor of the electric cylinder, the first gear contains a first magnetic steel, and the second gear contains a second magnetic steel; The encoder includes: a first encoder and a second encoder, the first encoder and the second encoder are connected to the first gear and the second gear respectively, and the first encoder and the second encoder are used to detect the position of the first magnetic steel and the position of the second magnetic steel respectively.

3. The absolute position detection device for an electric cylinder according to claim 2, characterized in that: The difference in the number of teeth between the first gear and the second gear is 2.

4. The absolute position detection device for an electric cylinder according to claim 3, characterized in that: The number of teeth of the first gear is 68 and the number of teeth of the second gear is 70.

5. The absolute position detection device for an electric cylinder according to claim 1, characterized in that: The encoder is arranged on the circuit board where the micro control unit is located.

6. A control method for an absolute position detection device of an electric cylinder according to any one of claims 1 to 5, characterized in that: The following steps are involved: respectively obtaining the position of each magnetic steel detected by the encoder; Fitting a curve of the maximum absolute difference between the positions of the magnetic steels and the absolute position of the electric cylinder according to the position of each magnetic steel; Calculate the maximum absolute difference between the positions of the magnets when power is off and on again; Obtaining the absolute position of the electric cylinder according to the maximum absolute difference between the positions of the magnetic steels calculated when power is turned on again and the curve; The method of fitting a curve of the maximum absolute difference between the positions of the magnetic steels and the absolute position of the electric cylinder according to the position of each magnetic steel specifically includes: Calculating the maximum absolute difference between the positions of the magnetic steels when the electric cylinder is powered on for the first time to obtain the maximum absolute difference between the positions of the magnetic steels at the zero position of the electric cylinder; The maximum absolute difference between the positions of the magnetic steels is calculated by controlling the forward and reverse rotation of the electric cylinder motor for a preset number of turns, so as to obtain the maximum absolute difference between the positions of the magnetic steels at the maximum stroke of the electric cylinder; According to the maximum absolute difference between the positions of the magnetic steels at the zero position and the maximum absolute difference between the positions of the magnetic steels at the maximum stroke, a curve of the maximum absolute difference between the positions of the magnetic steels and the absolute position of the electric cylinder is fitted.

7. An electric cylinder, characterized in that: An absolute position detection device comprising the electric cylinder according to any one of claims 1-5.

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