WO2018181473A1 - Rotation control device - Google Patents

Abstract

A rotation control device is provided with a relative position sensor (1) for detecting mechanical displacement in the rotation direction of an operation object shaft in non-contact fashion, and ON/OFF sensors (2_1-2_n) for outputting a sensing signal when the operation object shaft reaches predetermined intermediate positions (Pa, Pm, Pb) in the rotation direction of the operation object shaft, the ON/OFF sensors being provided with: a substrate (20) having principal surfaces (20a, 20b) orthogonal to the axis of the operation object shaft; electrodes (21a, 21b) disposed on the principal surfaces of the substrate; contactors (201a, 201b), other-end sides of which contact a single electrode when the operation object shaft is in a predetermined intermediate position; a detection circuit (23_i) for outputting a sensing signal when the contactors contact the electrode; and a plurality of cam members (24a, 24b) for moving the other ends of the contactors away from the principal surfaces when the operation object shaft is not in a predetermined intermediate position, the cam members (24a, 24b) being disposed on the principal surfaces of the substrate.

Description

Rotation control device

The present invention relates to a rotation control device that controls rotation of an operation target shaft, for example, a rotation control device that uses a valve shaft of a control valve as an operation target shaft.

In general, a rotation control device that controls the rotation of an operation target shaft such as a valve shaft detects a mechanical displacement in the rotation direction of the operation target shaft by a position sensor, and determines an operation amount of the shaft based on the detection result. Yes. For example, in an electric operating device (actuator) that operates a valve shaft of a rotary control valve such as a ball valve, a potentiometer including a variable resistor is used as a position sensor, and the rotational direction of the valve shaft detected by the potentiometer is adjusted. The valve shaft is controlled based on the mechanical displacement amount (see Patent Document 1).

As a position sensor for measuring the amount of mechanical displacement in the rotation direction of the shaft, in addition to a contact type position sensor represented by a potentiometer, the position of the measurement target shaft in the rotation direction, such as a rotary encoder, is used. There is a non-contact type position sensor that detects non-contact. Further, the non-contact position sensor outputs an absolute position sensor that outputs a signal corresponding to the angular position of the detection target axis, and a signal corresponding to the rotation angle of the detection target axis, that is, the amount of change in the angular position. There is a relative position sensor. For example, as a non-contact type absolute position sensor, an absolute rotary encoder that outputs a code signal corresponding to the absolute angular position of the detection target axis is used. As a non-contact type relative position sensor, a detection target is used. Incremental rotary encoders that output pulses corresponding to the rotation angle of the shaft are known (see Patent Document 2).

JP2011-074935A JP 2010-286444 A

Generally, since a potentiometer is a sensor that outputs a change in resistance value by mechanically operating a slider, its durability is low and its product life tends to be short. In addition, when an absolute rotary encoder as an absolute non-contact position sensor is used instead of a potentiometer, the unit price is generally high and a battery for driving the absolute rotary encoder is required. As a result, the product cost increases.

Therefore, the present inventor uses a non-contact type relative position sensor such as a rotary encoder and an ON / OFF sensor that outputs a detection signal when the operation target axis reaches a predetermined position, instead of the potentiometer. Proposed a new rotation control device (Japanese Patent Application No. 2017-0334014). In this rotation control device, for example, as shown in FIG. 18, the ON / OFF sensors 3_1 to 3_5 are provided in the vicinity of the operation target shaft 301, and the main board of the printed circuit board 300 on which the IC chip 302 for performing various arithmetic processes is mounted. An electrode 321 is disposed on the surface 300a. Then, the short plate 303 connected to the operation target shaft 301 is brought into contact with any one of the electrodes 321 to detect the absolute position of the operation target shaft 301 although it is discontinuous. Hereinafter, a position sensor that detects the absolute position of the operation target axis by using such an ON / OFF sensor may be referred to as a “discontinuous absolute position sensor”.

However, in such a configuration, if the short plate 303 is not brought into contact with the printed circuit board 300, fine adjustment of the distance between the short plate 303 and the printed circuit board 300 is required. This not only causes an increase in cost, but is not easy to realize. Further, there is a problem in the reliability of contact resistance due to the secular change of the spring property of the short plate 303. On the contrary, if the short plate 303 slides on the main surface 300a of the printed circuit board 300, the printed circuit board 300 may be adversely affected. As with the potentiometer, problems of durability and product life will occur.

The present invention has been made in view of the above problems, and an object of the present invention is to perform rotation control that measures the position of the operation target shaft in the rotation direction by using a non-contact type relative position sensor and an ON / OFF sensor. The object is to improve the durability and reliability of the apparatus while realizing it at a lower cost.

The rotation control device (100) for controlling the rotation of the operation target shaft (200) according to the present invention includes a relative position sensor (1) for detecting the mechanical displacement in the rotation direction of the operation target shaft in a non-contact manner, and the operation. In a rotatable range (SR) from the first position (Pc) to the second position (Po) in the rotation direction of the target axis, at least one predetermined intermediate position (Pa, excluding the first position and the second position) Pm, Pb) ON / OFF sensors (2_1 to 2_n) that output a detection signal when the operation target axis arrives, and mechanical displacement detected by the relative position sensor after the detection signal is output Based on the integrated value (RP) and a reference value (AP) indicating a predetermined intermediate position corresponding to the ON / OFF sensor that outputs the detection signal, an absolute position in the rotation direction of the operation target shaft is calculated. Position calculator (3 And the operation amount (MV) of the operation target axis based on the information on the target position (SP) in the rotation direction of the operation target axis and the absolute position (PV) of the operation target axis calculated by the position calculation unit. Based on the operation amount calculated by the operation amount calculation unit (4), and the operation amount calculated by the operation amount calculation unit, within the rotatable range from the first position to the second position in the rotation direction of the operation target axis An operation unit (5) for operating the shaft, and the ON / OFF sensor is provided around the operation target axis, and has a main surface (20a, 20b) perpendicular to the axis of the operation target axis, and a substrate (20) The at least one electrode (21a, 21b) arranged on the main surface of the substrate and one end are fixed to the operation target shaft, extend in the radial direction of the operation target shaft, and the operation target shaft is at a predetermined intermediate position. One part of the other end contacts one of the electrodes Contacts (201a, 201b), a detection circuit (23_i) that outputs a detection signal when the contact contacts one of the electrodes, and an operation target axis at a predetermined intermediate position. Cam members (24a, 24b) that move the other end of the contact in a direction away from the main surface when there is no contact.

In the rotation control device, the electrodes (21a, 21b) are arranged at positions corresponding to predetermined intermediate positions on the main surface, and the cam members (24a, 24b) have a circumference around the axis of the operation target shaft. It may be arranged along (C2), and the height from the main surface may decrease as it approaches a position corresponding to a predetermined intermediate position on the main surface along the circumference.

In the rotation control device, the electrodes (21a, 21b) and the cam members (24a, 24b) each have a first circumference (C1) having different radii around the axis of the operation target shaft on the main surface. The opposite end portions of two cam members that are arranged along the second circumference (C2) and are adjacent on the main surface of the cam members may be separated from each other on the main surface.

In the rotation control device, the electrodes (21a, 21b) and the cam members (24a, 24b) are arranged on the same circumference (C1) centering on the axis of the operation target shaft on the main surface, and the cam members (24a, 24b) are each formed of an insulating material, and the opposite end portions of two cam members adjacent to each other on the main surface of the cam member respectively cover a part of the electrode (21) and The electrodes may be separated from each other.

In the rotation control device, the contacts (201a, 201b) are elastically deformable plate-like members, and the width of the portion that contacts the electrode when the operation target shaft is at a predetermined intermediate position is on the main surface. It may be narrower than the interval between the ends of the two adjacent cam members facing each other.

In the rotation control device, the substrate has, as main surfaces, a first main surface (20a) and a second main surface (20b) opposite to the first main surface, and the electrodes are on the first main surface. At least one first electrode (21a) disposed on the second main surface and at least one second electrode (21b) disposed on the second main surface, and one end of the contact is fixed to the operation target shaft, A first contact (201a) that extends in a radial direction of the operation target shaft and has a part on the other end contacting one of the first electrodes when the operation target shaft is at a predetermined intermediate position; While electrically connected to the contact, one end is fixed to the operation target shaft, extends in the radial direction of the operation target shaft, and a part on the other end side is located when the operation target shaft is at a predetermined intermediate position. The second contactor (201b) is in contact with one of the second electrodes, and the cam member is disposed on the first main surface of the substrate. A plurality of first cam members (24a) for moving the other end of the first contact member away from the main surface when the operation target shaft is not at a predetermined intermediate position, and a second main surface of the substrate. A plurality of second cam members (24b) that move the other end of the second contactor away from the main surface when the operation target shaft is not at a predetermined intermediate position, and the detection circuit includes the first contact A detection signal may be output when a part of the other end of the child contacts the first electrode and a part of the other end of the second contact contacts the second electrode.

The rotation control device further includes a reversal number counting unit (6) that counts the number of times the rotation direction of the operation target axis is reversed, and the operation amount calculating unit (4A) counts the number of reversals without outputting a detection signal. Calculating an operation amount for moving the operation target axis to any one of the first position, the second position, and the predetermined intermediate position when the value counted by the unit exceeds a predetermined threshold value; In (5), the operation target axis may be operated based on the operation amount calculated by the operation amount calculation unit.

The rotation control device further includes an absolute value integration unit (7) that integrates the absolute value of the mechanical displacement in the rotation direction of the operation target shaft, and the operation amount calculation unit (4B) does not output a detection signal. When the value accumulated by the absolute value accumulation unit exceeds a predetermined threshold value, an operation amount for moving the operation target axis to any one of the first position, the second position, and the predetermined intermediate position is calculated. The operation unit (5) may operate the operation target axis based on the operation amount calculated by the operation amount calculation unit.

The rotation control device further includes a timer (8) for accumulating the time elapsed without outputting the detection signal, and the operation amount calculation unit (4C) has a predetermined time elapsed without outputting the detection signal. When the threshold value is exceeded, an operation amount for moving the operation target axis to any one of the first position, the second position, and the predetermined intermediate position is calculated, and the operation unit (5) calculates the operation amount. The operation target axis may be operated based on the operation amount calculated by the unit.

The rotation control device further includes an activation number counting unit (9) that counts the number of times the operation target axis starts to move, and the operation amount calculation unit (4D) is counted by the activation number counting unit without outputting a detection signal. When the calculated value exceeds a predetermined threshold, an operation amount for moving the operation target axis to any one of the first position, the second position, and the predetermined intermediate position is calculated, and an operation unit ( In 5), the operation target axis may be operated based on the operation amount calculated by the operation amount calculation unit.

In the rotation control device, the position calculation unit (3) includes a reference value update unit (32) that resets an integrated value of the mechanical displacement detected by the relative position sensor when a detection signal is output. Also good.

In the above description, as an example, reference numerals on the drawing corresponding to the components of the invention are shown in parentheses.

As described above, according to the present invention, while realizing a rotation control device that measures the position of the operation target shaft in the rotation direction by using a non-contact type relative position sensor and an ON / OFF sensor, it can be realized at lower cost. , Its durability and reliability can be improved.

FIG. 1 is a diagram illustrating a configuration of a rotation control device according to the first embodiment. FIG. 2 is a diagram for explaining the concept of a discontinuous absolute position sensor. FIG. 3A is a diagram illustrating an example of a configuration of a discontinuous absolute position sensor. FIG. 3B is a diagram illustrating an example of a configuration of a discontinuous absolute position sensor. FIG. 3C is a diagram illustrating an example of a configuration of a discontinuous absolute position sensor. FIG. 3D is a diagram illustrating an example of a configuration of a discontinuous absolute position sensor. FIG. 3E is a diagram illustrating a relationship between an electrode and a cam member in an example of a configuration of a discontinuous absolute position sensor. FIG. 4 is a flowchart for explaining the operation in the origin return operation mode of the rotation control device according to the first embodiment. FIG. 5 is a flowchart for explaining the operation in the normal operation mode of the rotation control device according to the first embodiment. FIG. 6A is a diagram illustrating another configuration example of a discontinuous absolute position sensor. FIG. 6B is a diagram illustrating the relationship between the electrode and the cam member in another configuration example of the discontinuous absolute position sensor. FIG. 7A is a diagram showing a modification of the discontinuous absolute position sensor. FIG. 7B is a diagram for explaining the relationship between the electrode and the cam member in a modification of the discontinuous absolute position sensor. FIG. 7C is a diagram showing a modification of the discontinuous absolute position sensor. FIG. 7D is a diagram showing a modification of the discontinuous absolute position sensor. FIG. 8 is a diagram illustrating a configuration of the rotation control device according to the second embodiment. FIG. 9A is a flowchart for explaining the operation of the rotation control device according to the second embodiment. FIG. 9B is a flowchart for explaining the operation of the rotation control device according to the second embodiment. FIG. 10 is a diagram illustrating a configuration of the rotation control device according to the third embodiment. FIG. 11A is a flowchart for explaining the operation of the rotation control device according to the third embodiment. FIG. 11B is a flowchart for explaining the operation of the rotation control device according to the third embodiment. FIG. 12 is a diagram illustrating a configuration of the rotation control device according to the fourth embodiment. FIG. 13A is a flowchart for explaining the operation of the rotation control device according to the fourth embodiment. FIG. 13B is a flowchart for explaining the operation of the rotation control device according to the fourth embodiment. FIG. 14 is a diagram illustrating a configuration of the rotation control device according to the fifth embodiment. FIG. 15A is a flowchart for explaining the operation of the rotation control device according to the fifth embodiment. FIG. 15B is a flowchart for explaining the operation of the rotation control device according to the fifth embodiment. FIG. 16A is a diagram illustrating another arrangement example of discontinuous absolute position sensors. FIG. 16B is a diagram illustrating another configuration example of the discontinuous absolute position sensor. FIG. 17A is a diagram illustrating another arrangement example of discontinuous absolute position sensors. FIG. 17B is a diagram illustrating another configuration example of the discontinuous absolute position sensor. FIG. 18 is a diagram for explaining an example of the configuration of a discontinuous absolute position sensor in the prior application.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals are given to components common to the respective embodiments, and repeated description is omitted.

<Embodiment 1>
≪Configuration of rotation control device≫
FIG. 1 is a diagram illustrating a configuration of a rotation control device 100 according to the first embodiment.
The rotation control device 100 shown in the figure is an electric operating device that controls the rotation of a valve shaft (operation target shaft) of a rotary control valve such as a ball valve used for flow rate process control in a plant or the like. It is.

Specifically, the rotation control device 100 includes a target value (set value) SP of the valve opening of the control valve and an actually measured value of the valve opening of the control valve (hereinafter referred to as “actual opening”) given from a host device (not shown). Also referred to as “degree”.) Deviation ΔP from PV is calculated. Then, the rotation control device 100 controls the valve opening of the control valve so as to become the target value SP by driving the valve shaft 200 so that the deviation ΔP becomes zero.

Hereinafter, a specific configuration of the rotation control device 100 will be described.
As shown in FIG. 1, the rotation control device 100 includes a relative position sensor 1, a plurality of ON / OFF sensors 2_1 to 2_n (n is an integer of 2 or more), a position calculation unit 3, an operation amount calculation unit 4, and An operation unit 5 is provided. The plurality of ON / OFF sensors 2_1 to 2_n constitute discontinuous absolute position sensors.

These components are accommodated in a housing made of, for example, a metal material. The rotation control device 100 transmits and receives data to and from a display unit (for example, a liquid crystal display) and an external device for presenting various types of information such as the valve opening of the control valve to the user in addition to the above-described functional unit. A communication circuit or the like may be provided.

First, the discontinuous absolute position sensor including the relative position sensor 1 and the ON / OFF sensors 2_1 to 2_n for measuring the actual opening of the control valve, that is, the position of the valve shaft 200 in the rotation direction will be described.

The relative position sensor 1 is a functional unit that detects a mechanical displacement Md in the rotation direction of the valve shaft 200 as an operation target shaft of the rotation control device 100 in a non-contact manner. An example of the relative position sensor 1 is an incremental rotary encoder that outputs a pulse corresponding to the rotation angle of the detection target shaft (valve shaft 200). In the present embodiment, the relative position sensor 1 will be described as an incremental rotary encoder.

On the other hand, the discontinuous absolute position sensor includes ON / OFF sensors 2_1 to 2_n, and corresponds to the predetermined position when the valve shaft 200 which is the operation target shaft reaches a predetermined position in the rotation direction. The provided ON / OFF sensors 2_1 to 2_n output detection signals P1 to Pn, respectively. The ON / OFF sensors 2_1 to 2_n may be any component that can output an electric signal indicating that the valve shaft 200 has reached a specific position in the rotation direction. Specifically, for example, limit switches can be used as the ON / OFF sensors 2_1 to 2_n. Here, the electrical signal may be a signal indicating that the valve shaft 200 has reached a specific position in the rotation direction, and is, for example, an on / off signal (a signal indicating a state, for example, a digital signal).

The arrangement of the ON / OFF sensors 2_1 to 2_n will be described with reference to FIG. FIG. 2 shows an arrangement example of the ON / OFF sensors 2_1 to 2_5 when n = 5.

As shown in FIG. 2, the ON / OFF sensors 2_1 to 2_5 are provided corresponding to a plurality of different positions within the rotatable range SR of the valve shaft 200, and the valve shaft 200 reaches the corresponding position. Detection signals P1 to Pn are output.

Here, the rotatable range SR is a rotatable range in the rotation direction of the valve shaft 200. For example, from the fully closed position Pc where the valve opening degree as the first position in the rotation direction is 0%, The range up to the fully open position Po where the valve opening as the position is 100% is shown.

In the rotation control device 100, the ON / OFF sensors 2_1 to 2_5 are provided corresponding to any position in the range of the valve opening from 0% to 100%. For example, in the arrangement example shown in FIG. 2, the ON / OFF sensor 2_1 is provided corresponding to the fully closed position Pc where the valve opening degree is 0%. The ON / OFF sensor 2_2 is provided corresponding to the position Pa where the valve opening degree is 20%. The ON / OFF sensor 2_3 is provided corresponding to the position Pm at which the valve opening is 50%. The ON / OFF sensor 2_4 is provided corresponding to the position Pb at which the valve opening is 70%. Furthermore, the ON / OFF sensor 2_5 is provided corresponding to the fully open position Po where the valve opening degree is 100%.
In the valve shaft 200, except for the fully closed position Pc where the valve opening is 0% and the fully opened position Po where the valve opening is 100%, the position Pa where the valve opening is 20% and the valve opening is 50 % Position Pm and the position Pb where the valve opening degree is 70% correspond to the “predetermined intermediate position” in the present invention.

2, the ON / OFF sensor 2_1 outputs the detection signal P1 when the valve shaft 200 reaches the fully closed position Pc. The ON / OFF sensor 2_2 outputs a detection signal P2 when the valve shaft 200 reaches the position Pa (valve opening: 20%). The ON / OFF sensor 2_3 outputs a detection signal P3 when the valve shaft 200 reaches the position Pm (valve opening: 50%). The ON / OFF sensor 2_4 outputs a detection signal P4 when the valve shaft 200 reaches the position Pb (valve opening: 70%). The ON / OFF sensor 2_5 outputs a detection signal P5 when the valve shaft 200 reaches the fully open position Po (valve opening degree: 100%).

Next, a specific structure of the ON / OFF sensors 2_1 to 2_n will be described.
The ON / OFF sensors 2_1 to 2_n are provided around the valve shaft 200. The ON / OFF sensors 2_1 to 2_n include a printed circuit board 20 having a first main surface 20a and a second main surface 20b orthogonal to the axis of the valve shaft 200, and the first main surface 20a and the second main surface 20b of the printed circuit board. A plurality of first electrodes 21 a and second electrodes 21 b respectively disposed on the top, a short plate 201 fixed to the side surface of the valve shaft 200, and a plurality of first contacts 201 a and second contacts 201 b of the short plate 201. A detection circuit 23_i that outputs a detection signal Pi when it contacts one of the first electrode 21a and the second electrode 21b, and a plurality of first cam members 24a disposed on the first main surface 20a of the printed circuit board 20; And a plurality of second cam members 24b disposed on the second main surface 20b.

Hereinafter, the first main surface 20a and the second main surface 20b of the printed circuit board 20 may be collectively referred to as “ main surfaces 20a, 20b”. The first electrode 21a and the second electrode 21b may be collectively referred to as “ electrodes 21a, 21b”. Further, the first contact 201a and the second contact 201b of the short plate 201 may be collectively referred to as “ contacts 201a and 201b”. The first cam member 24a and the second cam member 24b may be collectively referred to as “ cam members 24a, 24b”.

3A to 3E are diagrams showing an example of a specific structure of the ON / OFF sensors 2_1 to 2_n. Here, the case where n = 5 is illustrated.

3A and 3B, the valve shaft 200 is in the fully closed position Pc, position Pa (valve opening: 20%), position Pm (valve opening: 50%), and position Pb (valve opening: 70%) and a fully open position Po (valve opening degree: 100%) in a state where the ON / OFF sensors 2_1 to 2_n have been reached. 3C and 3D are a plan view schematically showing the structure of the ON / OFF sensors 2_1 to 2_n when the valve shaft 200 has not reached any of the predetermined positions, and II-II, respectively. It is line sectional drawing. FIG. 3E is a side view schematically showing the structure of the ON / OFF sensors 2_1 to 2_n.

In this example, each ON / OFF sensor 2_i (1 ≦ i ≦ n) is connected to a resistor R and an electrode 21a on a printed circuit board 20 provided around the valve shaft 200, as shown in FIGS. 3A to 3E. This can be realized by arranging 21b and providing a short plate 201 on the valve shaft 200.

Specifically, the first electrode 21a is formed on the first main surface 20a of the printed circuit board 20, and a resistor R is connected between the first electrode 21a and the power supply line Vcc to which the power supply voltage is supplied. Further, the second electrode 21b is formed on the second main surface 20b of the printed circuit board 20, and the second electrode 21b is connected to a ground line GND to which a ground voltage is supplied. The plurality of electrodes 21 a and 21 b formed on the two main surfaces 20 a and 20 b of the printed circuit board 20 are arranged along a circumference C <b> 1 centering on the axis of the valve shaft 200. Here, the resistor R may be disposed on the first main surface 20a of the printed circuit board 20, for example. The power supply line Vcc may be formed on the first main surface 20a of the printed circuit board 20, for example, and the ground line GND may be formed on the second main surface 20b of the printed circuit board 20, for example.

On the first main surface 20 a of the printed circuit board 20, an IC chip 30 including a program processing device such as a microcontroller or a CPU that functions as a position calculation unit 3 and an operation amount calculation unit 4 described later is disposed. Here, the node na to which the resistor R and the electrode 21 a are connected is connected to one input terminal of the IC chip 30.

The valve shaft 200 is inserted through a through hole 20 c provided in the printed circuit board 20. The axis of the valve shaft 200 and the principal surfaces 20a, 20b of the printed circuit board 20 are orthogonal to each other. A short plate 201 is joined to the outer peripheral surface of the valve shaft 200.

3B and 3D, the short plate 201 is formed, for example, in a “U” shape in a side view. The short plate 201 may be formed, for example, by bending a strip-shaped plate member made of a metal such as brass or stainless steel into a “U” shape in a side view. Such a short plate 201 is fixed to the side surface of the valve shaft 200 with a screw or the like. As a result, the short plate 201 is electrically connected to the first contact 201a, one end of which is fixed to the valve shaft 200 and extending in the radial direction of the valve shaft 200, and the first contact 201a. In addition, one end of the short plate 201 is fixed to the valve shaft 200 to provide the second contactor 201b extending in the radial direction of the valve shaft 200. Both the first contact 201a and the second contact 201b are plate-like members that can be elastically deformed. The printed circuit board 20 is disposed between the pair of contacts 201a and 201b. In this state, the contacts 201a 'and 201b' of these contacts 201a and 201b are urged in the direction of the two main surfaces 20a and 20b on the front and back sides of the printed circuit board 20, respectively. Therefore, the short plate 201 fixed to the valve shaft 200 rotates together with the valve shaft 200 in a state where the pair of opposed contacts 201 a and 201 b sandwich the printed circuit board 20.

Here, the valve shaft 200 is in the fully closed position Pc, the position Pa where the valve opening is 20%, the position Pm where the valve opening is 50%, the position Pb where the valve opening is 70%, and the fully opened position Po. Let us consider a case in which any of the positions is reached. In this case, the contacts 201a and 201b of the short plate 201 are in contact with the electrodes 21a and 21b arranged at positions corresponding to these predetermined positions. For example, as shown in FIG. 3A, when the valve shaft 200 rotates and the short plate 201 reaches the position of the ON / OFF sensor 2_3, the contact 201a ′ of the short plate 201 is connected to the electrode 21a of the ON / OFF sensor 2_3. Contact. Further, the contact 201b 'of the short plate 201 is in contact with the electrode 21b of the ON / OFF sensor 2_3. At this time, a current path is formed from the power supply line Vcc to the ground line GND through the resistor R, the electrode 21a, the short plate 201, and the electrode 21b, and the potential of the node na becomes 0 V (ground potential).

On the other hand, as shown in FIG. 3C, consider a case where the short plate 201 is between the ON / OFF sensor 2_1 and the ON / OFF sensor 2_2, that is, the valve shaft 200 is not at a predetermined intermediate position. In this case, the contacts 201a 'and 201b' of the short plate 201 are not in contact with any of the electrodes 21a and 21b of the ON / OFF sensors 2_1 to 2_5. As a result, the potential of the node na of each of the ON / OFF sensors 2_1 to 2_5 becomes Vcc (power supply voltage).

In this way, by detecting the voltage change at the node na of each of the ON / OFF sensors 2_1 to 2_5 as a detection signal to the IC chip 30, it is possible to detect that the valve shaft 200 has reached a predetermined position in the rotation direction. It becomes possible. Therefore, the resistor R having one end connected to the power supply line Vcc, the electrode 21a connected to the other end of the resistor R, and the electrode 21b connected to the ground line GND are contactors 201a and 201b of the short plate 201. The detection circuit 23_i that outputs the detection signal Pi is configured when a part of the other end of the electrode contacts one of the electrodes 21a and 21b.

Further, in the present embodiment, the ON / OFF sensors 2_1 to 2_5 include a cam member 24a disposed on the first main surface 20a of the printed circuit board 20, and a cam member 24b disposed on the second main surface 20b. It has. As shown in FIGS. 3A and 3C, these cam members 24 a and 24 b are arranged on the two principal surfaces 20 a and 20 b of the printed circuit board 20 along a circumference C <b> 2 centering on the axis of the valve shaft 200. Has been.

The cam members 24a and 24b are made of a material such as plastic, and each approach a position corresponding to a predetermined intermediate position on the main surface along the circumference C2, that is, a position where the electrodes 21a and 21b are disposed. It has a shape in which the height from the main surface is reduced. The mutually opposing ends of the two cam members adjacent to each other on the two main surfaces 20a and 20b are separated from each other.
In order to fix the cam members 24a and 24b to the printed circuit board 20 with an adhesive, an adhesive or a screw may be used. Instead of mounting the cam members 24a and 24b on the printed circuit board 20, the cam members 24a and 24b may be formed on a structure such as a resin case (not shown).

3D shows a discontinuous absolute position when the valve shaft 200 is not in a predetermined position, that is, the fully closed position Pc, the position Pa, the position Pm, the position Pb, or the fully opened position Po shown in FIG. It is a figure explaining the mode of a sensor. As shown in FIG. 3D, when the valve shaft 200 is not in any of the predetermined positions, the contacts 201a and 201b of the short plate 201 are cams provided on both main surfaces 20a and 20b of the printed circuit board 20, respectively. It contacts the members 24a and 24b. Then, the other ends of the contacts 201a and 201b move in a direction away from both the main surfaces 20a and 20b of the printed circuit board 20. Therefore, in this case, the contacts 201a ′ and 201b ′ of the contacts 201a and 201b do not contact the main surfaces 20a and 20b of the printed circuit board 20.
On the other hand, when the valve shaft 200 is in one of the predetermined positions, as shown in FIG. 3B, the contacts 201a and 201b of the short plate 201 are in contact with the electrodes 21a and 21b.

Next, the position calculation unit 3, the operation amount calculation unit 4, and the operation unit 5 will be described.

The position calculation unit 3 is a functional unit that calculates the absolute position of the valve shaft 200. The position calculation unit 3 outputs the integrated value RP of the mechanical displacement Md detected by the relative position sensor 1 after the detection signals P1 to Pn of the ON / OFF sensors 2_1 to 2_n are output, and the detection signals P1 to Pn. Based on the reference value AP indicating the position corresponding to the ON / OFF sensors 2_1 to 2_n that output Pn, the absolute position in the rotation direction of the operation target shaft is calculated.

The position calculation unit 3 can be realized by program processing by a program processing device such as a microcontroller or CPU. In the case of the above-described example, this is realized by the IC chip 30 placed on the printed circuit board 20.

More specifically, the position calculation unit 3 includes a reference value update unit 32, a relative position information acquisition unit 31, and a position determination unit 33.

The reference value updating unit 32 is a functional unit that updates the reference value AP and outputs the reset signal RST when the detection signals P1 to Pn are output from the ON / OFF sensors 2_1 to 2_n.

Here, the reference value AP is a value indicating an absolute position within the rotatable range SR, and serves as a reference when calculating the absolute position of the valve shaft 200 in the rotation direction.

Specifically, each time the ON / OFF sensors 2_1 to 2_n output the detection signals P1 to Pn, the reference value update unit 32 corresponds to the reference value AP to the ON / OFF sensors 2_1 to 2_n that output the detection signals. Set to a value that indicates the position to perform. For example, in the example of FIG. 2, first, when the valve shaft 200 rotates and reaches the position Pa where the valve opening degree becomes 20%, and the ON / OFF sensor 2_2 outputs the detection signal P2, the reference value update unit No. 32 sets the reference value AP to a value indicating the position Pa corresponding to the ON / OFF sensor 2_2. Thereafter, when the valve shaft 200 further rotates and the valve shaft 200 reaches the position Pm at which the valve opening degree is 50% and the ON / OFF sensor 2_3 outputs the detection signal P3, the reference value update unit 32 The value AP is changed from a value indicating the position Pa to a value indicating the position Pm corresponding to the ON / OFF sensor 2_3.

The relative position information acquisition unit 31 is a functional unit that acquires the mechanical displacement Md in the rotational direction of the valve shaft 200 detected by the relative position sensor 1 and calculates an integrated value RP of the mechanical displacement Md. For example, the relative position information acquisition unit 31 counts pulses output from an incremental rotary encoder as the relative position sensor 1 and calculates an integrated value RP of the number of pulses.

Further, when the reset signal RST is output from the reference value update unit 32, the relative position information acquisition unit 31 resets the integrated value RP of the number of pulses counted so far. After reset, the relative position information acquisition unit 31 resumes the pulse counting operation.

That is, the relative position information acquisition unit 31 resets the integrated value RP every time a detection signal is output from any of the ON / OFF sensors 2_1 to 2_n. Therefore, the integrated value RP calculated by the relative position information acquisition unit 31 is an accumulation of the number of pulses output from the rotary encoder from when the reference value AP is updated immediately before the reference value AP is updated next time. Value.

The position determination unit 33 is a mechanical displacement amount in the rotational direction of the valve shaft 200 based on the reference value AP generated by the reference value update unit 32 and the integrated value RP of the number of pulses calculated by the relative position information acquisition unit 31. And the absolute position of the valve shaft 200 in the rotatable range SR is calculated. The position determination unit 33 converts the calculated absolute position of the valve shaft 200 into a valve opening, and outputs the converted value as the actual opening PV.

The operation amount calculation unit 4 is based on the target value SP of the valve opening as the target position in the rotation direction of the valve shaft 200 and the actual opening PV calculated by the position calculation unit 3. Is a functional unit for calculating The operation amount calculation unit 4 can be realized, for example, by program processing by a program processing device such as a microcontroller or CPU, similarly to the position calculation unit 3. In the case of the above-described example, this is realized by the IC chip 30 placed on the printed circuit board 20.

Specifically, the operation amount calculation unit 4 includes a target value acquisition unit 41, a deviation calculation unit 42, and an operation amount determination unit 43.

The target value acquisition unit 41 is a functional unit that acquires the target value SP of the valve opening given from, for example, a host device (not shown) in the valve control system. The target value SP is set by communication from an external controller or an analog signal of 4-20 mA, for example.

The deviation calculating unit 42 is a functional unit that calculates a deviation ΔP between the target value SP of the valve opening acquired by the target value acquiring unit 41 and the actual opening PV calculated by the position calculating unit 3.

The operation amount determination unit 43 calculates the operation amount MV necessary until the valve shaft 200 reaches the target position in the rotation direction based on the target value SP, based on the deviation ΔP calculated by the deviation calculation unit 42.

The operation unit 5 is a functional unit that operates the valve shaft 200 within the rotatable range SR based on the operation amount MV calculated by the operation amount calculation unit 4. Specifically, the operation unit 5 includes an electric motor 52, an electric motor drive unit 51, and a speed reducer 53.

The electric motor 52 is a component that generates a rotational force for operating the valve shaft 200. Examples of the electric motor 52 include a brushless motor, a stepping motor, and a synchronous motor.

The electric motor drive unit 51 is a functional unit that drives the electric motor 52. Specifically, the electric motor drive unit 51 rotates the output shaft of the electric motor 52 by applying a current (or voltage) corresponding to the operation amount MV calculated by the operation amount calculation unit 4 to the electric motor 52. .

The speed reducer 53 is a power transmission mechanism that reduces the rotational force generated by the electric motor 52 and transmits it to the valve shaft 200. For example, the speed reducer 53 is configured by various gear mechanisms such as a planetary gear mechanism. By connecting the output shaft of the speed reducer 53 to the valve shaft 200, the valve shaft 200 can be rotated by the rotational force obtained by reducing the rotational force of the electric motor 52 with a predetermined reduction ratio.

<< Operation Principle of Rotation Control Device 100 according to Embodiment 1 >>
Next, the operation principle of the rotation control device 100 according to the first embodiment will be described.
First, the origin return operation by the rotation control device 100 will be described.

FIG. 4 is a diagram showing an operation flow in the origin return operation mode of the rotation control device 100 according to the first embodiment.
Here, the case where the valve shaft 200 has reached the position where the valve opening degree becomes 80% when the power of the rotation control device 100 is turned on will be described as an example.

When the rotation control device 100 is powered on, the rotation control device 100 starts operation in an origin return operation mode in which the origin return process of the relative position sensor 1 is performed. In the origin return operation mode, the rotation control device 100 drives the electric motor 52 in the direction to close the control valve (S11). Specifically, the electric motor drive unit 51 drives the electric motor 52 based on the operation amount MV calculated by the operation amount determination unit 43 so that the valve opening degree becomes 0%.

Next, the rotation control device 100 determines whether or not a detection signal is output from the ON / OFF sensors 2_1 to 2_n (S12). If no detection signal is output from the ON / OFF sensors 2_1 to 2_n in step S12, the rotation control device 100 continues to drive the electric motor 52 so that the valve opening degree becomes 0%.

On the other hand, when a detection signal is output from the ON / OFF sensors 2_1 to 2_n in step S12, the rotation control device 100 sets the position corresponding to the ON / OFF sensors 2_1 to 2_n that output the detection signal to the valve shaft. A reference value AP (initial point) for calculating the absolute position of 200 is set (S13).

For example, in the case of the example of FIG. 2, the valve shaft 200 rotates in the direction of 0% from the position where the valve opening degree becomes 80% in step S11, and then the valve shaft moves to the position Pb where the valve opening degree becomes 70%. When 200 reaches, the detection signal P4 is output from the ON / OFF sensor 2_4. At this time, the reference value update unit 32 in the position calculation unit 3 sets a value indicating the position Pb corresponding to the ON / OFF sensor 2_4 that has output the detection signal P4 as the reference value AP, and outputs a reset signal RST.

The relative position information acquisition unit 31 that has received the reset signal RST from the reference value update unit 32 resets the integrated value RP of the number of pulses counted so far (S14).

Thus, the origin return process is completed, and the rotation control device 100 shifts from the origin return operation mode to the normal operation mode.

Next, the operation of the rotation control device 100 in the normal operation mode after returning to the origin will be described.
FIG. 5 is a flowchart showing an operation flow in the normal operation mode of the rotation control device according to the first embodiment.

The rotation control device 100 shifts to the normal operation mode when the origin return operation mode ends. In the normal operation mode, the rotation control device 100 stands by until an instruction to change the target value SP of the valve opening degree is given from the host device (S20). When the change of the target value SP of the valve opening is instructed, the deviation calculating unit 42 of the rotation control device 100 performs the actual opening PV based on the absolute position of the valve shaft 200 calculated by the position calculating unit 3. Is larger than the target value SP instructed from the host device (S21).

In step S21, when the actual opening PV is larger than the target value SP, the rotation control device 100 drives the electric motor 52 in a direction to close the control valve (S22a). Specifically, the operation amount determination unit 43 calculates the operation amount MV so that the valve opening becomes the target value SP based on the deviation ΔP calculated by the deviation calculation unit 42, and the electric motor drive unit 51 The electric motor 52 is driven based on the operation amount MV.

On the other hand, when the actual opening PV is smaller than the target value SP in step S21, the rotation control device 100 drives the electric motor 52 in a direction to open the control valve (S22b). Specifically, the operation amount determination unit 43 calculates the operation amount MV based on the deviation ΔP calculated by the deviation calculation unit 42 so that the valve opening becomes the target value SP. Then, the electric motor drive unit 51 drives the electric motor 52 based on the operation amount MV.

After step S22a or step S22b, the rotation control device 100 determines whether or not a detection signal is output from one of the ON / OFF sensors 2_1 to 2_n (S23).

If no detection signal is output from the ON / OFF sensors 2_1 to 2_n in step S23, the rotation control device 100 acquires the reference value AP set by the reference value update unit 32 immediately before and the relative position information. Based on the mechanical displacement of the valve shaft 200 based on the integrated value RP of the number of output pulses from the relative position sensor 1 calculated by the unit 31, the actual opening PV (the absolute position of the valve shaft 200) is calculated. Calculate (S26).

For example, consider a case where no detection signal has been output from the ON / OFF sensors 2_1 to 2_n after the above-described origin return processing (steps S11 to S14). In this case, the reference value AP (in the above example, the position at which the valve opening is 70%) set in step S13 of the origin return operation mode is based on the integrated value RP calculated by the relative position information acquisition unit 31. The actual opening PV is calculated by adding the mechanical displacement of the valve shaft 200.

On the other hand, when a detection signal is output from the ON / OFF sensors 2_1 to 2_n in step S23, the rotation control device 100 updates the reference value AP (S24). Specifically, the reference value update unit 32 sets the position corresponding to the ON / OFF sensors 2_1 to 2_n that output the detection signal as a new reference value AP. For example, in the above-described origin return operation mode, the detection signal P3 is output from the ON / OFF sensor 2_3 in step S23 immediately after the reference value AP is set to a value indicating the position Pb (valve opening: 70%). To do. In this case, the reference value updating unit 32 changes the reference value AP from a value indicating the position Pb (valve opening: 70%) to a value indicating the position Pm (valve opening: 50%). At this time, the reference value update unit 32 also outputs a reset signal RST.

The relative position information acquisition unit 31 that has received the reset signal RST from the reference value update unit 32 resets the integrated value RP of the number of output pulses of the relative position sensor 1 that has been counted so far (S25).

Next, the rotation control device 100 is based on the reference value AP set by the reference value update unit 32 in step S24 and the integrated value RP counted by the relative position information acquisition unit 31 after being reset in step S25. The actual opening PV (absolute position of the valve shaft 200) is calculated (S26). For example, when the reference value AP is changed to a value indicating the position Pm (valve opening: 50%) in step S24, the reference value AP is counted by the relative position information acquisition unit 31 after step S25. The mechanical displacement amount of the valve shaft 200 based on the integrated value RP is added. Thereby, the rotation control apparatus 100 calculates the absolute position of the valve shaft 200, and calculates the actual opening PV from the position.

Next, rotation control device 100 determines whether or not actual opening PV calculated in step S26 matches target value SP (S27).

In step S27, when the actual opening PV does not coincide with the target value SP, the process returns to step S21, and the rotation control device 100 performs the above-described processing (S21 to S26) again. On the other hand, when the actual opening PV coincides with the target value SP in step S27, the rotation control device 100 ends a series of processes for setting the valve opening to the target value SP.

<< Effect of rotation control device 100 according to Embodiment 1 >>
As described above, in the rotation control device 100 according to the present invention, the valve shaft 200 is fully closed in addition to the non-contact type relative position sensor 1 as a position sensor for measuring the position of the valve shaft 200 in the rotation direction. ON / OFF sensors 2_2 to 2_4 are provided that output detection signals when reaching third positions (Pa, Pm, Pb) excluding the position Pc and the fully open position Po. The rotation control device 100 includes a reference value AP indicating a position corresponding to the ON / OFF sensors 2_2 to 2_4 that output the detection signal, and a mechanical position detected by the relative position sensor 1 after the detection signal is output. Based on the integrated value RP of the displacement Md, the absolute position of the valve shaft 200 in the rotational direction is calculated.

According to this, not only the fully closed position Pc and the fully opened position Po but also the third position can be regarded as a reference point in the position measurement of the valve shaft 200, that is, the “origin”. For this reason, it is possible to reduce the time required for the origin return process compared to the case where only the fully closed position Pc or the fully open position Po is set as the origin.

Specifically, when n ON / OFF sensors 2_1 to 2_n are arranged in the rotatable range SR, it is necessary to return the origin of the valve shaft 200 in the fully open position Po when the rotation control device 100 is turned on. The time T is represented by the following formula (1). Here, Tf is the time (full stroke time) required for the valve shaft 200 to move from the fully open position to the fully closed position.

For example, when five (n = 5) ON / OFF sensors 2_1 to 2_5 are arranged and the full stroke time Tf is 60 [seconds], the time required to return the valve shaft 200 at the fully open position Po to the origin. T is 60 / (5-1) = 15 [seconds].

As described above, according to the rotation control device 100 according to the present invention, the time required for returning the origin of the valve shaft 200 required when the relative position sensor 1 such as the incremental rotary encoder is used can be shortened. Is possible.
That is, in a rotation control device that measures the position of the operation target axis in the rotation direction using a non-contact type relative position sensor, the time required for the return of the origin of the operation target axis is shortened, and the position measurement error of the operation target axis is reduced. Can be reduced.

Further, the rotation control device 100 according to the present invention performs the same process as the return to origin every time the valve shaft 200 passes through the third position excluding the fully closed position Pc and the fully opened position Po. Specifically, when n = 5, the rotation control device 100 outputs the reference value AP as the reference value AP and outputs the detection signal when the detection signal is output from the ON / OFF sensors 2_2 to 2_4. The value is updated to a value indicating a position corresponding to 2_2 to 2_4, and the integrated value RP is reset.

According to this, even when the rotation control device 100 is operated for a long time, the above-described accumulation of backlash of the gears constituting the speed reducer 53 and the like, and the electric motor 52 as an electric motor such as a stepping motor and a synchronous motor. The measurement error of the mechanical displacement amount of the valve shaft 200 by the relative position sensor 1 due to the step-out of the electric motor when the motor is used in an open loop and the fluctuation of the power supply frequency when the synchronous motor is used is reduced. can do. Thereby, it becomes possible to perform the valve opening degree control of the control valve more accurately.

Further, according to the rotation control device 100, by providing a plurality of ON / OFF sensors 2_1 to 2_n, even if one of the ON / OFF sensors 2_1 to 2_n fails, the other ON / OFF sensors 2_1 to 2_n Thus, the valve opening degree control can be continued. Thereby, the reliability as the rotation control apparatus 100 can be improved.

Further, by increasing the number of ON / OFF sensors 2_1 to 2_n installed in the rotatable range SR, the time required for returning to the origin and the measurement error of the mechanical displacement amount of the valve shaft 200 by the relative position sensor 1 can be further reduced. It becomes possible to do.

<Another configuration example of the cam member>
In the first embodiment described above, the example in which the cam members 24a and 24b are arranged on the main surfaces 20a and 20b of the printed circuit board 20 has been described. However, the arrangement of the cam members 24a and 24b is not limited to this. As described below, instead of the cam members 24 a and 24 b, for example, a single plate-like member having a corrugated surface may be disposed on each of the main surfaces 20 a and 20 b of the printed circuit board 20. . An example of the configuration of a discontinuous absolute position sensor using such a cam member will be described with reference to FIGS. 6A and 6B.

FIG. 6A is a diagram showing another configuration example of a discontinuous absolute position sensor. FIG. 6B is a diagram schematically showing a part of a cross section at the circumference C1 in FIG. 6A. 6A and 6B are diagrams illustrating the relationship between the electrode and the cam member in this other configuration example.

As shown in FIG. 6A, in this other configuration example, the electrodes 21a (21b) of the ON / OFF sensors 2_1 to 2_5 are centered on the axis of the valve shaft 200 on the main surface 20a (20b) of the printed circuit board 20. They are arranged on the same circumference C1. In this respect, the configuration example shown in FIG. 6A is in common with the discontinuous absolute position sensor shown in FIGS. 3A to 3E. On the other hand, one cam member 34 a (34 b) formed in an arc shape in plan view is on a circumference C 2 centering on the axis of the valve shaft 200 on the main surface 20 a (20 b) of the printed circuit board 20. Has been placed. In this respect, the configuration example shown in FIG. 6A is different from the discontinuous absolute position sensor shown in FIGS. 3A to 3E.

In other configuration examples, the cam members 34a and 34b are each formed of an insulating material. The surfaces of the cam members 34a and 34b are each formed in a wave shape along the circumference C2. When the cam members 34a and 34b are respectively disposed on the two main surfaces 20a and 20b of the printed circuit board 20, the portions corresponding to the wavy bottoms in the radial direction centered on the valve shaft 200 are the ON / OFF sensors 2_1 to. It corresponds to the electrodes 21a and 21b of 2_5.

Accordingly, the contacts 201a and 201b of the short plate 201 move in the circumferential direction while being in contact with the cam members 34a and 34b, and when the valve shaft 200 is not in any of the predetermined positions, the cam members 34a and 34b are contacted. The other end sides of 201a and 201b are moved away from both main surfaces 20a and 20b. In this case, the contacts 201 a ′ and 201 b ′ of the contacts 201 a and 201 b do not contact the main surfaces 20 a and 20 b of the printed circuit board 20. On the other hand, when the valve shaft 200 is in any one of the predetermined positions, the heights of the cam members 34a and 34b from both the main surfaces 20a and 20b of the printed circuit board 20 are reduced. Therefore, the contacts 201a and 201b of the short plate 201 are in contact with the electrodes 21a and 21b.

Further, as shown in FIG. 6B, by devising the surface shape of the cam members 34a and 34b, the range in which the contacts 201a and 201b of the short plate 201 can contact the electrodes 21a and 21b along the circumference C1 is set. W is desirable. More specifically, it is desirable that the distance W be in a range that is slightly wider than the width of the contact portions 201a and 201b that are in contact with the electrodes 21a and 21b, and as close as possible to the width of the contacts 201a and 201b. The reason is as follows.

Since the electrodes 21a and 21b have a width in the direction of the circumference C1, even if the valve shaft 200 reaches the same position, the rotation angle of the valve shaft 200 and the detection circuit 23_i of the detection circuit 23_i depend on the direction when reaching the position. So-called hysteresis occurs in which the relationship with the output is different. On the other hand, as in this other configuration example, the surface shape of the cam members 34a and 34b is devised to limit the range in which the electrodes 21a and 21b and the contacts 201a and 201b can be in electrical contact to the interval W. Thus, the hysteresis can be reduced.

<Modified example of discontinuous absolute position sensor>
As described above, the discontinuous absolute position sensor has hysteresis because the electrodes 21a and 21b of the ON / OFF sensors 2_1 to 2_5 have a width in the circumferential C1 direction. Therefore, a modification of the discontinuous absolute position sensor having a configuration for reducing this hysteresis will be described.

FIG. 7A is a diagram showing a modification of the discontinuous absolute position sensor. FIG. 7B is a diagram schematically showing a part of a cross section at the circumference C1 in FIG. 7A. FIG. 7C is a view showing a cross section taken along line III-III shown in FIG. 7A. 7A to 7C are views for explaining the relationship between the electrode and the cam member in this modification.
As shown in FIG. 7A, the discontinuous absolute position sensor according to this modification includes electrodes 21a and 21b and cam members 44a and 44b on the main surfaces 20a and 20b of the printed circuit board 20, respectively. Are arranged on the same circumference C <b> 1 centered on the axis. In this respect, the discontinuous absolute position sensor according to this modification is different from that shown in FIGS. 3A to 3E.

In this other configuration example, the cam members 44a and 44b are each formed of an insulating material. As shown in FIG. 7B, each of the cam members 44a and 44b extends between the adjacent electrodes 21a and 21b. As shown in FIGS. 7A and 7B, of the cam members 44a and 44b, the two cam members adjacent to each other on the main surfaces 20a and 20b are opposite to each other, respectively, of the electrodes 21a and 21b. Covers the part. End portions of the two cam members adjacent to each other on the main surfaces 20a and 20b are separated from each other on the electrodes 21a and 21b.

FIG. 7B illustrates that two adjacent first cam members 44a arranged on the first main surface 20a are arranged along the circumference C1 with an interval Wg therebetween. Similarly, the second cam members 44b adjacent to each other on the second main surface 20b are also arranged with a gap Wg along the circumference C1. Therefore, the electrodes 21a and 21b are exposed over the interval Wg along the direction in which the contacts 201a and 201b of the short plate 201 move, that is, along the circumference C1, and the other portions are covered by the cam members 44a and 44b. It has been broken.

Therefore, when the valve shaft 200 is not in any of the predetermined positions, the contacts 201a and 201b of the short plate 201 come into contact with the cam members 44a and 44b, respectively, and from both main surfaces 20a and 20b of the printed circuit board 20. Move in the direction of separation. On the other hand, when the valve shaft 200 is in one of the predetermined positions, as shown in FIGS. 7A and 7B, the contacts 201a ′ and 201b ′ of the contacts 201a and 201b of the short plate 201 are in contact with the electrodes 21a and 21b, respectively. Then, a detection signal is output.
At this time, as shown in FIG. 7B, the end portions of the cam members 44a and 44b cover a part of the electrodes 21a and 21b, and the range in which the electrodes 21a and 21b and the contacts 201a and 201b can be electrically contacted is the distance Wg. It is limited to. Therefore, the accuracy of position detection of the valve shaft 200 can be increased and the hysteresis can be reduced.

Further, the cam members 44a and 44b in this modified example have grooves formed along the circumference C1 in a state of being disposed on the main surfaces 20a and 20b of the printed circuit board 20. Therefore, as shown in FIG. 7A, when the valve shaft 200 is not in a predetermined position and the contacts 201a and 201b of the short plate 201 are positioned between the electrodes in plan view, the contacts 201a and 201b are The cam members 44a and 44b are contacted at positions other than the contacts 201a ′ and 201b ′. Therefore, as shown in FIG. 7C, the contacts 201a ′ and 201b ′ do not contact the cam members 44a and 44b by the grooves. Therefore, it is possible to prevent wear of the contacts and contribute to improvement in reliability and durability.
In this modification, as shown in FIG. 7C, an example in which grooves are provided in the cam members 44a and 44b has been described. However, instead of providing a groove, as shown in FIG. 7D, the thickness of the cam members 44a ′ and 44b ′ or the height from the main surfaces 20a and 20b of the printed circuit board 20 is radially outward from the valve shaft 200. The cam members 44 a ′ and 44 b ′ may be formed in a shape that becomes lower as going to.

<Effects of other configuration examples>
Since the electrodes 21a and 21b have a width in the direction of the circumference C1, even if the valve shaft 200 reaches the same position, the rotation angle of the valve shaft 200 and the detection circuit 23_i of the detection circuit 23_i depend on the direction when reaching the position. So-called hysteresis occurs in which the relationship with the output is different. On the other hand, in this other configuration example, as shown in FIG. 7B, the ends of the cam members 44a and 44b cover parts of the electrodes 21a and 21b, and the electrodes 21a and 21b and the contacts 201a and 201b The range in which electrical contact can be made is limited to the interval Wg. Thereby, it is possible to approach the structure in which the contacts 201a and 201b and the electrodes 21a and 21b are in contact only when the valve shaft 200 is in a predetermined position. Therefore, the accuracy of position detection can be improved and the hysteresis can be reduced.

From the viewpoint of reducing hysteresis, the accuracy can be improved by making the interval Wg as narrow as possible.
Further, the cam members 44 a and 44 b may be provided with grooves, or may have surfaces inclined with respect to the main surfaces 20 a and 20 b of the printed circuit board 20. With such a configuration, the contacts 201a ′ and 201b ′ of the contacts 201a and 201b do not come into contact with the cam member or other members other than the electrode 21a. Therefore, the lifetime and reliability of the ON / OFF sensor can be improved.

<Embodiment 2>
When the rotation control device according to the first embodiment is continuously operated without turning off the power, the return-to-origin process is not performed for a long time. Therefore, the accumulated value of the number of output pulses of the rotary encoder and the amount of mechanical displacement in the actual direction of rotation of the valve shaft due to the accumulation of backlash generated in the gears constituting the speed reducer when the rotation direction of the valve shaft is switched. And a difference occurs in the measurement result of the valve opening.
Even when a plurality of ON / OFF sensors are arranged, backlash may accumulate if the valve shaft repeatedly moves between adjacent ON / OFF sensors.

Therefore, the rotation control device according to the second embodiment reduces a measurement error associated with the accumulation of backlash in the rotation control device that measures the position of the operation target shaft in the rotation direction using a non-contact relative position sensor. With the goal.
<< Configuration of Rotation Control Device According to Embodiment 2 >>
FIG. 8 is a diagram illustrating a configuration of the rotation control device according to the second embodiment.
The rotation control device 100A according to the second embodiment counts the number of times that the rotation direction of the valve shaft 200 is reversed, and detects the relative position sensor 31 by operating the valve shaft 200 when the count value exceeds a threshold value. It has a forced reset function based on the so-called number of reversals in the rotational direction of the valve shaft 200, which resets the integrated value RP of the mechanical displacement Md. In this respect, rotation control device 100A is different from rotation control device 100 according to the first embodiment. Since the other configuration including the configuration of the ON / OFF sensor is the same as that of the first embodiment described above, the common components are denoted by the same reference numerals, and detailed description thereof is omitted.

Specifically, the rotation control device 100A further includes a reversal count unit 6. The inversion number counting unit 6 counts the number of times that the rotation direction of the valve shaft 200 as the operation target shaft is inverted, and holds the count value. The inversion number counting unit 6 can be realized by, for example, a counter and a program built in the microcontroller.

For example, the reversal number counting unit 6 stores the direction in which the valve shaft 200 has been rotated immediately before, and then reverses when the direction in which the valve shaft 200 is rotated is different from the direction in which the valve shaft 200 has been rotated immediately before. The number of times Rc is incremented. On the other hand, when the direction in which the valve shaft is rotated next coincides with the direction in which the valve shaft 200 has been rotated immediately before, the inversion number counting unit 6 does not increment the inversion number Rc.

Further, the inversion number counting unit 6 resets the inversion number Rc when the detection signals are output from the ON / OFF sensors 2_1 to 2_n. For example, the inversion number counting unit 6 receives the reset signal RST output from the reference value update unit 32 and resets the inversion number Rc.

The operation amount calculation unit 4A turns on the valve shaft 200 by operating the valve shaft 200 via the operation unit 5 when the number of inversions Rc counted by the inversion number counting unit 6 exceeds a predetermined threshold value Rt. / Rotate to a position corresponding to any one of the OFF sensors 2_1 to 2_n.

Specifically, the operation amount determination unit 43A in the operation amount calculation unit 4A monitors the number of inversions Rc by the inversion number counting unit 6. When the inversion number Rc exceeds the threshold value Rt, the operation amount determination unit 43A rotates the valve shaft 200 to a position corresponding to any one of the ON / OFF sensors 2_1 to 2_n, and resets the integrated value RP. Process (forced reset process).

In the forced reset process, from the viewpoint of time reduction, the position of the valve shaft 200 is turned ON / OFF closest to the position of the valve shaft 200 (short plate 201) at the time when the count value of the inversion counter 6 exceeds the threshold value. It is preferable to move to a position corresponding to the sensors 2_1 to 2_n. On the other hand, when the operation target shaft is a valve shaft, the valve may be moved in a closing direction or an opening direction depending on the use of the valve.

After the forced reset process, the operation amount determination unit 43A determines the operation amount MV based on the deviation ΔP calculated by the deviation calculation unit 42, similarly to the operation amount determination unit 43 according to the first embodiment.

<< Operation Principle of Rotation Control Device 100A according to Embodiment 2 >>
Next, the operation in the normal operation mode of the rotation control device 100A according to the second embodiment will be described.
9A and 9B are flowcharts showing a flow of operations in the normal operation mode of the rotation control device 100A according to the second embodiment.

First, similarly to the rotation control device 100 according to the first embodiment, the rotation control device 100A shifts to the normal operation mode when the origin return operation mode ends. In the normal operation mode, rotation control device 100A waits until a change in target value SP of the valve opening is instructed from the host device (S20).

In step S20, when an instruction to change the valve opening target value SP is given, in the second embodiment, a forced reset process (S3) based on the number of times the rotation direction of the valve shaft 200 is reversed is executed. FIG. 9B shows the procedure of forced reset processing based on the number of times of inversion.
First, the inversion number counting unit 6 of the rotation control device 100A determines whether or not the valve shaft 200 is inverted, that is, whether or not the direction in which the valve shaft 200 is rotated next is opposite to the direction in which the valve shaft 200 is rotated immediately before. It is determined whether or not (S30). When it is determined in step S30 that the valve shaft 200 does not reverse, the rotation control device 100A ends the forced reset process (S3) based on the number of reversals, returns to the main routine, and performs the processes of steps S21 to S27. Execute.
Note that a series of processing from step S21 to S27 is the same as that of the rotation control device 100 according to the first embodiment, and thus detailed description thereof is omitted.

On the other hand, if it is determined in step S30 that the valve shaft 200 is reversed, the reversal number counting unit 6 increments the reversal number Rc (S31).

Next, the operation amount determination unit 43A determines whether or not the number of inversions Rc counted by the inversion number counting unit 6 is larger than the threshold value Rt (S32). In step S32, when the number of inversions Rc does not exceed the threshold value Rt, the rotation control device 100A ends the forced reset process (S3) based on the number of inversions, returns to the main routine, and rotates according to the first embodiment. Similar to the control device 100, the processes of steps S21 to S27 are executed.

On the other hand, when the number of inversions Rc is larger than the threshold value Rt in step S32, the operation amount calculation unit 4A calculates (φh−φ) and (φ−φl), respectively, and (φ−φl) ≦ (φh It is determined whether or not −φ) (S33). Here, φh indicates an opening corresponding to any of the ON / OFF sensors 2_1 to 2_n that is larger than the current valve opening φ and closest to the current valve opening φ. For example, if the current valve opening φ is 60%, φh is 70% (Pb, 2_4). Φl indicates an opening corresponding to any of the ON / OFF sensors 2_1 to 2_n that is smaller than the current valve opening φ and closest to the current valve opening φ. For example, if the current valve opening φ is 60%, φl is 50% (Pm, 2_3).

If the result of determination in step S33 is (φ−φ1) ≦ (φh−φ), the operation amount calculation unit 4A moves the valve shaft 200 in the direction to close the control valve (S34a). On the other hand, when (φ−φl)> (φh−φ), the operation amount calculation unit 4A moves the valve shaft 200 in the direction to open the control valve (S34b).

After step S34a or step S34b, the rotation control device 100 determines whether a detection signal is output from the ON / OFF sensors 2_1 to 2_n (S35). If no detection signal is output from the ON / OFF sensors 2_1 to 2_n in step S35, the rotation control device 100 returns to step S33 and performs the above-described processing (S33 to S35) again.

On the other hand, when a detection signal is output from any one of the ON / OFF sensors 2_1 to 2_n in step S35, the rotation control device 100 stops the electric motor (S36) and updates the reference value AP. (S37). Specifically, the reference value update unit 32 sets the position corresponding to the ON / OFF sensors 2_1 to 2_n that output the detection signal as a new reference value AP. At this time, the reference value update unit 32 also outputs a reset signal RST.

The relative position information acquisition unit 31 receives the reset signal RST from the reference value update unit 32, and resets the integrated value RP of the number of output pulses from the relative position sensor 1 counted so far (S38). .

Further, the inversion number counting unit 6 receives the reset signal RST from the reference value updating unit 32 and resets the inversion number Rc that has been counted so far (S39).

The forced reset process (S3) based on the number of inversions is completed as described above, and the process returns to the main routine. Thereafter, rotation control apparatus 100A executes the processes of steps S21 to S27, as with rotation control apparatus 100 according to the first embodiment.
In step S25, when the integrated value RP is reset, the inversion number Rc by the inversion number counting unit 6 is similarly reset (step S39 in FIG. 9A).

<< Effect of rotation control apparatus 100A according to Embodiment 2 >>
In a general control valve control system, the valve shaft 200 may not reach the position corresponding to the ON / OFF sensors 2_1 to 2_n for a long time. For example, the situation where the valve shaft 200 moves back and forth between the position corresponding to the ON / OFF sensor 2_2 (valve opening: 20%) and the position corresponding to the ON / OFF sensor 2_3 (valve opening: 50%) is long. May last for hours. In this case, backlash accumulates, and an error may occur in the measurement result by the relative position sensor 1 (for example, an incremental rotary encoder).

On the other hand, according to rotation control device 100A according to the second embodiment, integrated value RP is forcibly reset when the number of inversions Rc exceeds a predetermined number (threshold value Rt). It becomes possible to suppress measurement errors caused by rush accumulation.

As described above, according to the rotation control device 100A according to the second embodiment, it is possible to further reduce the error in the position measurement of the operation target axis.

<Embodiment 3>
The rotation control device 100B according to the third embodiment aims to reduce a measurement error associated with the accumulation of backlash similarly to the rotation control device 100A according to the second embodiment. The rotation control device 100A according to the second embodiment integrates the mechanical displacement Md detected by the relative position sensor 31 by forcibly operating the valve shaft 200 based on the number of reversals in the rotation direction of the valve shaft 200. Configured to reset the value RP. In contrast, the rotation control device 100B according to the third embodiment forcibly operates the valve shaft 200 based on the integrated value of the movement distance of the valve shaft 200, and detects the machine detected by the relative position sensor 31. The rotation control device 100A according to the second embodiment is different from the rotation control device 100A according to the second embodiment in that the integrated value RP of the mechanical displacement Md is reset.
<< Configuration of Rotation Control Device According to Embodiment 3 >>
FIG. 10 is a diagram illustrating a configuration of a rotation control device 100B according to the third embodiment.
The rotation control device 100B according to the third embodiment integrates the movement distance of the valve shaft 200 when the valve shaft 200 does not reach the position corresponding to the ON / OFF sensors 2_1 to 2_n for a long time. Then, when the integrated value exceeds the threshold value, the valve shaft 200 is operated to reset the integrated value RP of the mechanical displacement Md detected by the relative position sensor 31, so-called integrated value of the movement distance of the valve shaft 200. A forced reset function based on In this respect, the rotation control device 100B according to the third embodiment is different from the rotation control device 100 according to the first embodiment and the rotation control device 100A according to the second embodiment. The configuration including the configurations of the ON / OFF sensors 2_1 to 2_n other than the forced reset process is the same as that in the first embodiment and the second embodiment described above. Therefore, in the following, common constituent elements are denoted by the same reference numerals, and detailed description thereof is omitted.

Specifically, the rotation control device 100B further includes an absolute value integration unit 7. The absolute value integration unit 7 integrates the movement distance in the rotation direction of the valve shaft 200 as the operation target shaft, and holds the integrated value. More specifically, the absolute value integration unit 7 integrates the absolute value | ΔP | of the mechanical displacement Md in the rotation direction of the valve shaft 200. For example, the absolute value integrating unit 7 integrates the absolute value | ΔP | of the mechanical displacement Md detected by the relative position sensor 1 and stores the integrated value RP. Such an absolute value integration unit 7 can be realized by, for example, a counter and a program built in the microcontroller.

The absolute value integration unit 7 resets the integrated value of the movement distance of the valve shaft 200 when detection signals are output from the ON / OFF sensors 2_1 to 2_n. For example, the absolute value integrating unit 7 receives the reset signal RST output from the reference value updating unit 32 and resets the integrated value of the movement distance of the valve shaft 200 in the rotation direction.

The operation amount calculation unit 4B operates the valve shaft 200 via the operation unit 5 when the integrated value of the movement distance in the rotational direction of the valve shaft 200 accumulated by the absolute value accumulation unit 7 exceeds a predetermined threshold value. Thus, the valve shaft 200 is rotated to a position corresponding to any one of the ON / OFF sensors 2_1 to 2_n.

Specifically, the operation amount determination unit 43B in the operation amount calculation unit 4B monitors the integrated value of the movement distance of the valve shaft 200, which is stored in the absolute value integration unit 7. When the integrated value of the movement distance of the valve shaft 200 exceeds a predetermined threshold, the operation amount determination unit 43B moves the valve shaft 200 to a position corresponding to any one of the ON / OFF sensors 2_1 to 2_n. A process of rotating and resetting the integrated value RP (forced reset process) is performed.

After the forced reset process, the operation amount determination unit 43B determines the operation amount MV based on the deviation ΔP calculated by the deviation calculation unit 42, similarly to the operation amount determination unit 43 according to the first embodiment.

<< Operation Principle of Rotation Control Device 100B according to Embodiment 3 >>
Next, the operation in the normal operation mode of the rotation control device 100B according to the third embodiment will be described.
FIG. 11A and FIG. 11B are flowcharts showing an operation flow in the normal operation mode of rotation control device 100B according to the third embodiment.

First, similarly to the rotation control device 100 according to the first embodiment, the rotation control device 100B shifts to the normal operation mode when the origin return operation mode ends. In the normal operation mode, steps S20 to S22a and S22b for driving the electric motor are the same as those in the first embodiment, and thus description thereof is omitted.

When the operation unit 5 drives the electric motor 52 to rotate the valve shaft 200 (step S22a or S22b), the rotation control device 100B executes a forced reset process (S4) based on the integrated value of the movement distance. The procedure of the forced reset process based on the integrated value of the movement distance of the valve shaft 200 is shown in FIG. 11B.
As shown in FIG. 11B, first, the absolute value of the mechanical displacement Md caused by the rotation of the valve shaft 200 by the operation unit 5, that is, the moving distance is integrated (S41).
Next, it is determined whether or not the integrated value of the movement distance integrated by the absolute value integrating unit 7 is larger than a predetermined threshold (S42). In step S42, when the integrated value of the movement distance does not exceed the threshold value, the rotation control device 100B ends the forced reset process (S4) based on the integrated value of the movement distance and returns to the main routine. Thereafter, similarly to the rotation control device 100 according to the first embodiment, the processes of steps S23 to S27 are executed.

On the other hand, when the integrated value of the movement distance is larger than the threshold value in step S42, the operation amount calculation unit 4B performs the forced reset process according to steps S33 to S38, similarly to the operation amount calculation unit 4A in the second embodiment. Execute. Since the procedure steps S33 to S38 of the forced reset process are the same as those in the second embodiment, description thereof is omitted.

When the detection signal is output from any of the ON / OFF sensors 2_1 to 2_n, the absolute value integrating unit 7 receives the reset signal RST from the reference value updating unit 32, and the valve shaft 200 up to that time is received. The integrated value of the movement distance is reset (S49).

Thus, the forced reset process (S4) based on the moving distance is completed, and the process returns to the main routine. Thereafter, the rotation control device 100B performs the processing of steps S23 to S27, similar to the rotation control device 100 according to the first embodiment. Execute.
When the integrated value RP is reset in step S25, the integrated value of the movement distance stored in the absolute value integrating unit 7 is similarly reset (step S49 in FIG. 11A).

<< Effect of rotation control device 100B according to Embodiment 3 >>
If the valve shaft 200 does not reach the position corresponding to the ON / OFF sensors 2_1 to 2_n for a long time, backlash accumulates, and the measurement result by the relative position sensor 1 (for example, an incremental rotary encoder). There is a risk of errors.

On the other hand, according to the rotation control device 100B according to the third embodiment, the integrated value of the movement distance of the valve shaft 200 is obtained in a situation where the valve shaft 200 does not reach the position corresponding to the ON / OFF sensors 2_1 to 2_n for a long time. When the threshold value is exceeded, the integrated value RP is forcibly reset. For this reason, it is possible to suppress measurement errors caused by the accumulation of backlash.

Therefore, according to the rotation control device 100B according to the third embodiment, it is possible to further reduce the error in the position measurement of the operation target axis.

<Embodiment 4>
Similarly to the rotation control devices according to the second and third embodiments, the rotation control device according to the fourth embodiment also measures the position of the operation target shaft in the rotation direction using a non-contact type relative position sensor. An object of the rotation control device is to reduce measurement errors due to accumulation of backlash.
<< Configuration of Rotation Control Device According to Embodiment 4 >>
FIG. 12 is a diagram illustrating a configuration of a rotation control device 100C according to the fourth embodiment.
The rotation control device 100C according to the second embodiment is configured when the valve shaft 200 does not reach the position corresponding to the ON / OFF sensors 2_1 to 2_n and the elapsed time without outputting the detection signal exceeds the threshold value. Then, the integrated value RP of the mechanical displacement Md detected by the relative position sensor 31 is reset by forcibly operating the valve shaft 200. In this regard, the rotation control device 100C according to the fourth embodiment is different from the rotation control device according to the first to third embodiments. In the following, the configuration including the configuration of the ON / OFF sensors 2_1 to 2_n other than the forced reset processing is the same as that of the first, second, and third embodiments described above, and thus the same components are denoted by the same reference numerals. Detailed description thereof will be omitted. The time that has elapsed without the valve shaft 200 reaching the position corresponding to the ON / OFF sensors 2_1 to 2_n and the detection signal being output may be referred to as “dwell time”.

Specifically, the rotation control device 100 </ b> C has a timer 8. The timer 8 counts the time that the valve shaft 200 as the operation target shaft has not reached the position corresponding to the ON / OFF sensors 2_1 to 2_n and the detection signal is not output, that is, the residence time, and the count Holds the value. The timer 8 can be realized by, for example, a clock circuit, a counter, and a program built in the microcontroller.

For example, when the valve shaft 200 reaches a position corresponding to the ON / OFF sensors 2_1 to 2_n and a detection signal is detected, the timer 8 is reset once and counts the time elapsed from that time as the residence time.

The operation amount calculation unit 4C operates the valve shaft 200 via the operation unit 5 when the residence time counted by the timer 8 exceeds a predetermined threshold value, thereby turning the valve shaft 200 on / off sensor 2_1˜. Rotate to a position corresponding to any one of 2_n.

Specifically, the operation amount determination unit 43C in the operation amount calculation unit 4C monitors the residence time counted by the timer 8. When the residence time exceeds a predetermined threshold value, the operation amount determination unit 43C rotates the valve shaft 200 to a position corresponding to any one of the ON / OFF sensors 2_1 to 2_n, and the integrated value RP Performs processing to reset (forced reset processing).

After the forced reset process, the operation amount determination unit 43A determines the operation amount MV based on the deviation ΔP calculated by the deviation calculation unit 42, similarly to the operation amount determination unit 43 according to the first embodiment.

<< Operation Principle of Rotation Control Device 100C according to Embodiment 4 >>
Next, the operation in the normal operation mode of the rotation control device 100C according to the fourth embodiment will be described.
FIG. 13A and FIG. 13B are flowcharts showing the operation flow in the normal operation mode of rotation control apparatus 100C according to the fourth embodiment.

Furthermore, similarly to the rotation control device 100 according to the first embodiment, the rotation control device 100C shifts to the normal operation mode when the origin return operation mode ends. In the normal operation mode, rotation control device 100C waits until a change in target value SP of the valve opening is instructed from the host device (S20).

In step S20, when the change of the target value SP of the valve opening degree is instructed, in the fourth embodiment, the forced reset process (S5) based on the residence time is executed. FIG. 13B shows a procedure for forced reset processing based on the residence time.
First, the operation amount determination unit 43C reads the residence time stored in the timer 8 (S51), and determines whether or not the residence time is greater than a threshold value (S52). In step S52, when the residence time does not exceed the threshold value, rotation control device 100C ends the forced reset process (S5), returns to the main routine, and is similar to rotation control device 100 according to the first embodiment. Then, the processes of steps S21 to S27 are executed.

On the other hand, when the residence time is larger than the threshold value in step S52, the operation amount calculation unit 4C executes the forced reset process according to steps S33 to S38, as in the operation amount calculation unit 4A in the second embodiment. . Since the procedure steps S33 to S38 of the forced reset process are the same as those in the second embodiment, description thereof is omitted.

In addition, when a detection signal is output from any of the ON / OFF sensors 2_1 to 2_n, the timer 8 receives the reset signal RST from the reference value update unit 32 and calculates the residence time counted so far. Reset (S59).

The forced reset process (S3) based on the number of inversions is completed as described above, and the process returns to the main routine. After that, the rotation control device 100C performs steps S21 to S27 in the same manner as the rotation control device 100 according to the first embodiment. Execute.
When the integrated value RP is reset in step S25, the dwell time that the timer 8 has counted so far is similarly reset (step S59 in FIG. 13A).

<< Effect of rotation control apparatus 100C according to Embodiment 4 >>
On the other hand, according to the rotation control device 100C according to the fourth embodiment, the integrated value RP is forcibly reset when the number of inversions Rc exceeds a predetermined number (threshold value Rt). It becomes possible to suppress measurement errors caused by rush accumulation.

As described above, according to the rotation control device 100C according to the fourth embodiment, it is possible to further reduce the error in the position measurement of the operation target axis.

<Embodiment 5>
Similar to the rotation control device 100A according to the second embodiment, the rotation control device 100D according to the fifth embodiment aims to reduce a measurement error due to the accumulation of backlash. The rotation control device 100A according to the second embodiment is configured to perform a forced reset process based on the number of reversals in the rotation direction of the valve shaft 200. On the other hand, the rotation control device 100D according to the fifth embodiment is compulsory based on the number of times the valve shaft 200 starts moving (hereinafter also referred to as “the number of times of activation”) regardless of the rotation direction of the valve shaft 200. It differs from rotation control apparatus 100A of the second embodiment in that it is configured to perform reset processing.

<< Configuration of Rotation Control Device According to Embodiment 5 >>
FIG. 14 is a diagram illustrating a configuration of a rotation control device 100D according to the fifth embodiment. The rotation control device 100D further includes an activation number counting unit 9, and when the activation number counted by the activation number counting unit 9 exceeds a predetermined threshold Rt, an operation amount calculation unit 4D that executes a forced reset process. Prepare.
Since the other configuration including the configuration of the ON / OFF sensor is the same as that of the above-described first embodiment, the same components are denoted by the same reference numerals, and detailed description thereof is omitted. .

The activation number counting unit 9 counts the number of times that the valve shaft 200 as the operation target shaft starts to move, and holds the value Rs. Specifically, since the valve shaft 200 rotates each time the target value SP is changed, the number of times the target value SP is changed may be counted as the number of activations. Such an activation number counting unit 9 can be realized by a counter and a program built in the microcontroller, for example.
When the detection signal is output from any of the ON / OFF sensors 2_1 to 2_n, the activation number counting unit 9 is reset by the reset signal RST output from the reference value update unit 32 of the position calculation unit 3.

In the normal mode, the operation amount calculation unit 4D is configured to control the valve opening based on the target value SP of the valve opening as the target position in the rotation direction of the valve shaft 200 and the actual opening PV calculated by the position calculation unit 3. An operation amount MV of the shaft 200 is calculated. On the other hand, when the forced reset process is executed, the valve shaft 200 is rotated to the position corresponding to any one of the ON / OFF sensors 2_1 to 2_n by operating the valve shaft 200 via the operation unit 5.

More specifically, the operation amount determination unit 43D monitors the number of activations counted by the activation number counting unit 9. When the number of activations exceeds the threshold, the operation amount determination unit 43D resets the integrated value RP by rotating the valve shaft 200 to a position corresponding to any one of the ON / OFF sensors 2_1 to 2_n. Processing (forced reset processing) is performed.

In the forced reset process, from the viewpoint of time saving, the position of the valve shaft 200 is turned ON / OFF closest to the position of the valve shaft 200 (short plate 201) when the count value of the activation number counting unit 9 exceeds the threshold value. It is preferable to move to a position corresponding to the sensors 2_1 to 2_n. On the other hand, when the operation target shaft is a valve shaft, the valve may be moved in a closing direction or an opening direction depending on the use of the valve.

After the forced reset process, the operation amount determination unit 43D determines the operation amount MV based on the deviation ΔP calculated by the deviation calculation unit 42, similarly to the operation amount determination unit 43 according to the first embodiment.

<< Operation Principle of Rotation Control Device 100D according to Embodiment 5 >>
Next, the operation in the normal operation mode of the rotation control device 100D according to the fifth embodiment will be described.
FIG. 15A and FIG. 15B are flowcharts showing an operation flow in the normal operation mode of rotation control device 100D according to the fifth embodiment.

First, similarly to the rotation control device 100 according to the first embodiment, the rotation control device 100D shifts to the normal operation mode when the origin return operation mode ends. In the normal operation mode, the rotation control device 100D stands by until a change in the target value SP of the valve opening is instructed from the host device (S20).

In Step S20, when an instruction to change the target value SP of the valve opening degree is given, a forced reset process (S6) based on the number of activations of the valve shaft 200 is executed.

FIG. 15B shows the procedure of forced reset processing based on the number of activations.
First, the activation number counting unit 9 of the rotation control device 100D increments the activation number (S61).

Next, the operation amount determination unit 43D determines whether or not the number of activations counted by the activation number counting unit 9 is greater than a preset threshold value (S62). In step S62, when the number of activations does not exceed the threshold value, rotation control device 100D ends the forced reset process (S6) based on the number of inversions and returns to the main routine.

On the other hand, when the number of activations is larger than the threshold value in step S62, the operation amount calculation unit 4B executes the forced reset process according to steps S33 to S38, similarly to the operation amount calculation unit 4A in the second embodiment. . Since the procedure steps S33 to S38 of the forced reset process are the same as those in the second embodiment, description thereof is omitted.

Further, when a detection signal is output from any of the ON / OFF sensors 2_1 to 2_n, the activation number counting unit 9 receives the reset signal RST from the reference value update unit 32 and resets the activation number up to that time. (S69).

The forced reset process (S6) based on the number of activations is thus completed, and the process returns to the main routine. Thereafter, rotation control apparatus 100D executes the processes of steps S23 to S27, as in rotation control apparatus 100 according to the first embodiment.
Note that a series of processing from step S21 to S27 is the same as that of the rotation control device 100 according to the first embodiment, and thus detailed description thereof is omitted.
Further, when the integrated value RP is reset in step S25, the number of activations stored in the activation number counting unit 9 is similarly reset (step S69 in FIG. 15A).

<< Effect of rotation control apparatus 100D according to Embodiment 5 >>
According to rotation control device 100D according to the fifth embodiment, integrated value RP is forcibly reset when the number of activations exceeds a predetermined number (threshold), so that measurement errors due to backlash accumulation can be suppressed. It becomes possible.

As described above, according to the rotation control device 100D according to the fifth embodiment, it is possible to further reduce the error in the position measurement of the operation target axis.

<Extension of Embodiment>
Although the invention made by the present inventors has been specifically described based on the embodiments, it is needless to say that the present invention is not limited thereto and can be variously modified without departing from the gist thereof. Yes.

For example, in the first embodiment described above, since the short plate 201 having a substantially “U” shape in side view is used, the electrodes 21 a and 21 b and the cam member 24 a are respectively provided on the two main surfaces 20 a and 20 b of the printed board 20. , 24b has been described. However, the electrode 21 and the cam member 24 may be disposed only on the printed circuit board 20, for example, only on the first main surface 20 a.

Further, for example, in the above embodiment, the valve shaft 200 is in the fully closed position Pc, the position Pa at which the valve opening is 20%, the position Pm at which the valve opening is 50%, and the valve opening is 70%. The case where the five ON / OFF sensors 2_1 to 2_5 are respectively installed at the five positions Pb and the fully opened position Po is shown. However, the position and number of the ON / OFF sensors 2_1 to 2_n to be installed are not limited to this. Hereinafter, another arrangement example of the ON / OFF sensors 2_1 to 2_n will be described.

FIG. 16A is a diagram illustrating another arrangement example of the ON / OFF sensors 2_1 to 2_n.
In this example, assuming that n = 3, the valve shaft 200 has a fully closed position Pc at which the valve opening degree is 0%, an intermediate point between the fully closed position Pc and the fully open position Po, that is, an intermediate position at which the valve opening degree is 50%. The case where three ON / OFF sensors 2_1, 2_2, 2_3 for detecting that the position Pm and the fully open position Po at which the valve opening degree is 100% is reached is shown. FIG. 16B is a diagram showing an arrangement example of the electrode 21 and the cam member 24 of the absolute position sensor corresponding to the arrangement example shown in FIG. 16A. As shown in FIG. 16B, a cam member 24 is provided between the electrodes 21 constituting the ON / OFF sensors 2_1, 2_2, and 2_3 in the circumferential direction.

According to this, when the valve shaft 200 reaches the fully closed position Pc, the fully opened position Po, and the intermediate position Pm between the fully closed position Pc and the fully opened position Po, the origin return (update of the reference value AP) is performed. Is done. Therefore, compared with the case where only the fully closed position Pc or the fully open position Po is set as the origin of the valve shaft 200, it is possible to reduce the time required for returning to the origin and the measurement error of the mechanical displacement amount by the relative position sensor 1. It becomes. Moreover, it becomes possible to suppress the additional cost by installing the ON / OFF sensor.

In FIG. 16A and FIG. 16B, the ON / OFF sensors 2_1 to 2_n are not both the fully closed position Pc where the valve opening degree is 0% and the fully open position Po where the valve opening degree is 100%. You may arrange in.

FIG. 17A is a diagram showing still another arrangement example of the ON / OFF sensors 2_1 to 2_n.
In this example, a case where one ON / OFF sensor 2 for detecting that the valve shaft 200 has reached the intermediate position Pm at which the valve opening degree is 50% is provided is shown. At this time, as shown in FIG. 17B, cam members 24 are arranged on both sides of the electrode 21 constituting the ON / OFF sensor 2. These cam members 24 are arranged along the track of the contact point of the short plate 201 between the fully closed position Pc and the intermediate position Pm and between the intermediate position Pm and the fully open position Po.

According to this, the origin return is performed at the position Pm which is an intermediate point between the fully closed position Pc and the fully opened position Po. Therefore, compared with the case where only the fully closed position Pc or the fully open position Po is set as the origin, it is possible to reduce the time required for the origin return and the measurement error of the mechanical displacement amount by the relative position sensor 1. In addition, since only one ON / OFF sensor is required, it is possible to further suppress the additional cost due to the installation of the ON / OFF sensor.

In the above embodiment, the case where an incremental rotary encoder is used as the relative position sensor 1 is exemplified. However, it can be used as the relative position sensor 1 as long as it can detect the mechanical displacement Md in the rotation direction of the operation target shaft without contact. For example, when a brushless motor is used as the electric motor 52, a signal output from a Hall element (Hall IC) constituting the brushless motor can be used as the relative position sensor 1.

Further, when a stepping motor is used as the electric motor 52, the position calculation unit 3 counts the pulse signal for driving the stepping motor without providing the relative position sensor 1 separately. It is also possible to calculate the mechanical displacement amount in the rotation direction.

Further, when a synchronous motor is used as the electric motor 52, the mechanical displacement amount in the rotation direction of the operation target shaft can be calculated without providing the relative position sensor 1 separately. For example, when the driving time for driving the synchronous motor is T [s], the rotation speed is N [rpm], and the reduction ratio of the speed reducer 53 is 1 / G, the rotation angle Φ [°] is (T × N × 360) / (60 × G). Therefore, the position calculation unit 3 can calculate the mechanical displacement amount in the rotation direction of the operation target shaft by performing the above calculation.

Further, in the above embodiment, the case where the rotation control device 100 is applied as an electric operating device that operates the valve shaft 200 of the control valve is illustrated. However, the operation target shaft operated by the rotation control device 100 is not limited to the valve shaft, and can be applied to any opening degree measurement system that uses a relative position sensor in the rotation control device. For example, the rotation control device 100 can be applied as a damper operating device that operates the damper shaft.

In the above embodiment, the case where the valve shaft 200 is inserted through the through hole 20c formed in the printed circuit board 20 is illustrated, but the present invention is not limited to the illustrated configuration. For example, as shown in FIG. 18, a cutout portion 20d having a semicircular shape in plan view may be provided on one side of the printed circuit board 20, and the valve shaft 200 may be disposed in the cutout portion 20d. In this case, the electrode 21a may be disposed around the notch 20d in the main surface 20a of the printed circuit board 20.

DESCRIPTION OF SYMBOLS 100 ... Rotation control apparatus (operator), 200 ... Valve shaft, 1 ... Relative position sensor, 2, 2_1 to 2_n ... ON / OFF sensor, 3 ... Position calculation part, 4, 4A ... Manipulation amount calculation part, 5 ... Operation unit, 6 ... Inversion count counting unit, 7 ... Absolute value integration unit, 8 ... Timer, 9 ... Activation count counting unit, 20 ... Printed circuit board, 20a, 20b ... Main surface, 21a, 21b ... Electrode, 201 ... Short plate , 201a, 201b ... contact, 23_i ... detection circuit, 24a, 24b ... cam member, 31 ... relative position information acquisition unit, 32 ... reference value update unit, 33 ... position determination unit, 41 ... target value acquisition unit, 42 ... Deviation calculation unit, 43 ... Operation amount determination unit, 51 ... Electric motor drive unit, 52 ... Electric motor, 53 ... Reduction gear, SP ... Target value, PV ... Actual opening, ΔP ... Deviation, MV ... Operation amount, RP ... integrated value, AP ... reference value, ST ... reset signal.

Claims (11)

1. A rotation control device for controlling rotation of an operation target shaft,
   A relative position sensor for detecting the mechanical displacement in the rotational direction of the operation target shaft in a non-contact manner;
   When the operation target shaft reaches at least one predetermined intermediate position excluding the first position and the second position in a rotatable range from the first position to the second position in the rotation direction of the operation target shaft. An ON / OFF sensor that outputs a detection signal to
   An integrated value of the mechanical displacement detected by the relative position sensor after the detection signal is output, and a reference indicating the predetermined intermediate position corresponding to the ON / OFF sensor that has output the detection signal A position calculation unit that calculates an absolute position in the rotation direction of the operation target axis based on the value;
   An operation amount calculation unit that calculates an operation amount of the operation target axis based on information on a target position in the rotation direction of the operation target axis and an absolute position of the operation target axis calculated by the position calculation unit. When,
   An operation unit that operates the operation target shaft within a rotatable range from the first position to the second position in the rotation direction of the operation target shaft based on the operation amount calculated by the operation amount calculation unit. And
   The ON / OFF sensor
   A substrate provided around the operation target axis and having a main surface orthogonal to the axis of the operation target axis;
   At least one electrode disposed on a major surface of the substrate;
   One end is fixed to the operation target shaft, extends in the radial direction of the operation target shaft, and a part of the other end side contacts one of the electrodes when the operation target shaft is at the predetermined intermediate position. A contactor,
   A detection circuit that outputs the detection signal when the contact contacts one of the electrodes;
   A cam member that is disposed on the main surface of the substrate and moves the other end of the contact member away from the main surface when the operation target shaft is not at the predetermined intermediate position;
   A rotation control device.
2. In the rotation control device according to claim 1,
   The electrode is disposed at a position corresponding to the predetermined intermediate position on the main surface,
   The cam member is disposed along a circumference centered on an axis of the operation target shaft, and the main surface as it approaches a position corresponding to the predetermined intermediate position on the main surface along the circumference. The height from
   Rotation control device.
3. In the rotation control device according to claim 2,
   The electrode and the cam member are respectively disposed along a first circumference and a second circumference having different radii around the axis of the operation target shaft on the main surface,
   End portions of the two cam members adjacent to each other on the main surface among the cam members are separated from each other on the main surface.
   Rotation control device.
4. In the rotation control device according to claim 2,
   The electrode and the cam member are disposed on the same circumference around the axis of the operation target shaft on the main surface,
   The cam members are each formed of an insulating material,
   The opposite end portions of the two cam members adjacent to each other on the main surface of the cam member respectively cover a part of the electrode and are separated from each other on the electrode.
   Rotation control device.
5. In the rotation control device according to claim 4,
   The contact is a plate-like member that can be elastically deformed,
   The width of the portion that contacts the electrode when the operation target shaft is at the predetermined intermediate position is narrower than the interval between the opposing ends of the two cam members adjacent on the main surface,
   Rotation control device.
6. In the rotation control device according to any one of claims 1 to 5,
   The substrate has, as the main surface, a first main surface and a second main surface opposite to the first main surface,
   The electrode comprises at least one first electrode disposed on the first main surface and at least one second electrode disposed on the second main surface,
   One end of the contact is fixed to the operation target shaft, extends in a radial direction of the operation target shaft, and a part of the other end side is the first when the operation target shaft is at the predetermined intermediate position. A first contact that contacts one of the electrodes, and is electrically connected to the first contact, one end of which is fixed to the operation target shaft, and extends in a radial direction of the operation target shaft; When the operation target shaft is at the predetermined intermediate position, a part of the other end side is composed of a second contact that contacts one of the second electrodes,
   The cam member is disposed on the first main surface of the substrate and moves in a direction to separate the other end of the first contact from the main surface when the operation target shaft is not at the predetermined intermediate position. A plurality of first cam members that are arranged on the second main surface of the substrate, and the other end of the second contact is separated from the main surface when the operation target shaft is not at the predetermined intermediate position. A plurality of second cam members that are moved in the direction of movement,
   The detection circuit detects the detection signal when a part of the other end side of the first contactor contacts the first electrode and a part of the other end side of the second contactor contacts the second electrode. Output,
   Rotation control device.
7. In the rotation control device according to any one of claims 1 to 6,
   A reversal number counting unit that counts the number of times the rotation direction of the operation target shaft is reversed;
   The operation amount calculation unit moves the operation target axis to the first position and the second position when a value counted by the inversion number counting unit exceeds a predetermined threshold without outputting the detection signal. And calculating the operation amount for moving to any one of the predetermined intermediate positions,
   The operation unit operates the operation target axis based on the operation amount calculated by the operation amount calculation unit.
   Rotation control device.
8. In the rotation control device according to any one of claims 1 to 6,
   An absolute value accumulating unit for accumulating the absolute value of the mechanical displacement in the rotation direction of the operation target shaft;
   The operation amount calculation unit moves the operation target axis to the first position and the second position when a value accumulated by the absolute value accumulation unit exceeds a predetermined threshold without outputting the detection signal. And calculating the operation amount for moving to any one of the predetermined intermediate positions,
   The operation unit operates the operation target axis based on the operation amount calculated by the operation amount calculation unit.
   Rotation control device.
9. In the rotation control device according to any one of claims 1 to 6,
   A timer for accumulating the elapsed time without the detection signal being output;
   The operation amount calculation unit moves the operation target axis between the first position, the second position, and the predetermined intermediate position when a time elapsed without outputting the detection signal exceeds a predetermined threshold. Calculate the operation amount to move to any one of them,
   The operation unit operates the operation target axis based on the operation amount calculated by the operation amount calculation unit.
   Rotation control device.
10. In the rotation control device according to any one of claims 1 to 6,
    An activation number counting unit that counts the number of times the operation target axis starts to move;
    The operation amount calculation unit moves the operation target axis to the first position and the second position when a value counted by the activation number counting unit exceeds a predetermined threshold without outputting the detection signal. And calculating the operation amount for moving to any one of the predetermined intermediate positions,
    The operation unit operates the operation target axis based on the operation amount calculated by the operation amount calculation unit.
    Rotation control device.
11. In the rotation control device according to any one of claims 1 to 10,
    The position calculation unit
    A reference value updating unit that resets an integrated value of the mechanical displacement detected by the relative position sensor when the detection signal is output from the ON / OFF sensor;
    Rotation control device.

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