JP2006258728A - Measuring device of rotation angle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately measure a rotation angle without an error by a certain and easy method even when waveform of individual rotation sensors is different. <P>SOLUTION: When a first detection signal 400A (voltage value VA) is inputted to a measurement controller 30 from the rotation sensor 100, correspondence relationship on the first detection signal 400A of the rotation sensor 100 is selected from a storage table 36, and rotation angles θA1 and θA2 corresponding to the present detection voltage value VA are read. Similarly, when a second detection signal 400B (voltage value VB) is inputted to the measurement controller 30 from the rotation sensor 100, correspondence relationship on the second detection signal 400B of the rotation sensor 100 is selected from the storage table 36, and rotation angles θB1 and θB2 corresponding to the present detection voltage value VB are read. Based on the first and second rotation angles, a stroke position of a hydraulic cylinder 200 is measured. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a rotation angle measuring device.

  Patent Documents 1 and 2 described later describe an invention in which a rotation angle is detected by configuring a rotation sensor as a magnetic sensor and detecting a magnetic force that changes according to the rotation.

In Patent Documents 1 and 2, the first detection signal and the second detection signal having different phases are output from the magnetic sensor, the waveforms of the first and second detection signals are regarded as sine waveforms, and a function of the sine waveform is obtained. Using the equation, the rotation angle of the output voltage of the rotation sensor is converted into engineering units.
Japanese Patent No. 2977821 JP 2001-241942 A

  When the rotation sensor is constituted by a magnetic sensor, there is a problem that an error is likely to occur in the measured value of the rotation angle. In addition, when applied to a system having a large number of measurement objects (for example, hydraulic cylinders) to which rotation sensors are attached, such as construction machinery, the output signal waveform differs for each rotation sensor, that is, at the same rotation angle. However, there is a problem that the detected voltage value is different for each rotation sensor.

  That is, when the magnetic force is a detection medium, the waveform of the detection signal of the rotation sensor is likely to be distorted due to the accuracy of the magnet to be detected, the magnet mounting error, or the like. Moreover, these distortions differ for each rotation sensor.

  Here, as seen in Patent Documents 1 and 2, the waveform output from each rotation sensor is regarded as a sine wave uniquely, and the output voltage of the rotation sensor is determined by uniformly using a functional expression of the sine waveform. Even if the engineering unit is converted into the rotation angle, the rotation angle measured thereby includes an error in the detection signal due to the distortion of the waveform. Further, since the distortion of the waveform of the detection signal is different for each rotation sensor, the measured value of the rotation angle varies.

  The present invention has been made in view of such a situation, and when performing a process of measuring a rotation angle based on a detection signal of a rotation sensor using magnetic force as a detection medium, it is a reliable and simple method with high accuracy and no error. An object of the present invention is to make it possible to measure the rotation angle.

The first invention is
A rotation sensor that uses magnetic force as a detection medium, the detection physical quantity periodically changing according to the rotation angle, and a rotation sensor that outputs first and second detection signals having different phases;
The correspondence between the physical quantity detected by the rotation sensor in advance and the rotation angle is stored,
Referring to the correspondence relationship, the first and second rotation angles corresponding to the first and second detection signals are obtained, and the rotation angle is determined based on the difference between the first rotation angle and the second rotation angle. And a measuring means for measuring.

The second invention is the first invention,
Selecting a first rotation angle and a second rotation angle at which the difference between the two rotation angles is equal to or less than a predetermined value, and measuring the rotation angle based on the selected first and second rotation angles. Features.

The third invention is
When the difference between the first rotation angle and the second rotation angle does not become a predetermined value or less, the rotation sensor is determined to be abnormal.

  The first invention will be specifically described with reference to FIGS. 9B and 10B.

  According to the first invention, as shown in FIG. 10B, the first detection signal 400A (voltage value VA) is input to the measurement controller 30 from the rotation sensor 100 provided in the boom hydraulic cylinder 200. Then, as shown in FIG. 9B, the correspondence relationship with respect to the first detection signal 400A of the rotation sensor 100 of the boom cylinder 200 is selected from the storage table 36, and the rotation corresponding to the current detection voltage value VA. Angles (hereinafter referred to as first rotation angles) θA1 and θA2 are read out. Similarly, when the second detection signal 400B (voltage value VB) is input to the measurement controller 30 from the rotation sensor 100 provided in the boom hydraulic cylinder 200, as shown in FIG. As shown in FIG. 9B, the correspondence relationship for the second detection signal 400B of the rotation sensor 100 of the boom cylinder 200 is selected from the table 36, and the rotation angle corresponding to the current detection voltage value VB (hereinafter referred to as “the detection angle value”) Second rotation angle) θB1 and θB2 are read out. The stroke position of the hydraulic cylinder 200 is measured based on the first and second rotation angles.

  As described above, the rotation angle is measured for each rotation sensor 100 based on the correspondence relationship between the detected voltage value and the rotation angle. Therefore, even if the waveform of each rotation sensor 100 is different, The rotation angle can be measured with high accuracy and no error by a simple method.

  The second invention and the third invention will be specifically described below.

  As described in the first invention, as shown in FIG. 10B, two values θA1, θA2, θB1, and θB2 are obtained for the first rotation angle and the second rotation angle, respectively.

  Therefore, differences between the first rotation angles θA1 and θA2 and the second rotation angles θB1 and θB2, that is, θA1−θB1, θA2−θB2, θA1−θB2, and θA2−θB1 are calculated. Then, among these combinations of the first and second rotation angles, the combination (θA2−θB1) having the smallest difference between the two rotation angles is selected. Next, it is determined whether or not the difference (θA2−θB1) between the selected combinations of the first and second rotation angles is equal to or less than a predetermined value, that is, whether or not there is an abnormality in both rotation angle differences.

  When the difference between the two rotation angles is less than or equal to a predetermined value, the boom hydraulic cylinder is based on the first rotation angle (θA2) and the second rotation angle (θB1) that are less than or equal to the predetermined value. 200 stroke positions are measured. For example, the stroke position of the boom hydraulic cylinder 200 is measured using the average value of the first rotation angle (θA2) and the second rotation angle (θB1) as the current rotation angle of the rotation roller 110 (second invention).

  On the other hand, when the difference between the first rotation angle and the second rotation angle is not less than the predetermined value, that is, for the combination of both rotation angles with the smallest difference (θA2−θB1), the difference is not less than the predetermined value. In this case, the rotation sensor 100 of the boom hydraulic cylinder 200 determines that an abnormality is currently occurring, and stops the measurement process (third invention).

  Therefore, according to the second aspect of the invention, the rotation angle can be reliably measured only when no abnormality has occurred based on the first and second detection signals 400A and 400B output from the rotation sensor 100. The reliability of measurement results can be improved.

  In addition, according to the third invention, the abnormality of the rotation sensor 100 can be determined based on the first and second detection signals 400A and 400B output from the rotation sensor 100, and the reliability of the measurement result is improved. Can be made.

  The present invention is not limited to the case where the rotation sensor 100 is mounted on a construction machine such as a hydraulic excavator and detects the stroke amount of the hydraulic cylinder. The machine on which the rotation sensor 100 is mounted and the detection target are arbitrary. .

  Embodiments of a rotation angle measuring device according to the present invention will be described below with reference to the drawings. In the following embodiments, a description will be given assuming that the rotation angle is measured in order to measure the stroke position of the hydraulic cylinder in the hydraulic working machine.

  1 and 2 show a hydraulic circuit of the hydraulic working machine according to the embodiment. The hydraulic working machine is assumed to be a construction machine such as a hydraulic excavator.

  FIG. 1 shows a configuration in which the hydraulic cylinder 200 is driven by supplying a hydraulic signal Pp from the hydraulic operation lever device 1 to the control valve 2 for the hydraulic cylinder 200.

  In FIG. 2, an electric signal St is input from the electric operation lever device 3 to the control controller (main controller) 20, and a control electric signal i is supplied from the control controller 20 to the control valve 4 for the hydraulic cylinder 200. Thus, the configuration in which the hydraulic cylinder 200 is driven is shown.

  First, the configuration of FIG. 1 will be described.

  The hydraulic excavator is provided with a plurality of work machines such as a boom, an arm, and a bucket, and each of the plurality of work machines is operated by driving a corresponding work machine hydraulic cylinder 200. In an actual hydraulic excavator, a hydraulic cylinder 200 is provided for each work machine. However, in FIG. 1, for convenience of explanation, one hydraulic cylinder 200 is illustrated and others are omitted.

  The hydraulic cylinder 200 is driven using, for example, a variable displacement hydraulic pump 5 as a drive source. The hydraulic pump 5 is driven by the engine 6.

  The swash plate 5 a of the hydraulic pump 5 is driven by the servo mechanism 7. The servo mechanism 7 operates in accordance with a control signal (electric signal) output from the control controller 20, and the swash plate 5a of the hydraulic pump 5 is changed to a position corresponding to the control signal. Further, the engine drive mechanism 8 (governor, injection pump, injector, etc.) of the engine 6 operates in accordance with a control signal (electric signal) output from the controller 20 for control, and generates a control signal in the cylinder of the engine 6. A corresponding amount of fuel is injected at a timing corresponding to the control signal, and the engine 6 rotates at a rotation speed corresponding to the control signal.

  The discharge port of the hydraulic pump 5 communicates with the inlet port of the control valve 2 through the discharge oil passage 9. The outlet port of the control valve 2 communicates with the oil chambers 204B and 204H of the hydraulic cylinder 200 via the oil passages 11 and 12.

  The pressure oil discharged from the hydraulic pump 5 is supplied to the control valve 2 through the discharge oil passage 9, and the pressure oil that has passed through the control valve 2 passes through the oil passage 11 or 12 to the oil chamber 204B of the hydraulic cylinder 200. Or it is supplied to the oil chamber 204H.

  The operating lever device 1 includes, for example, an operating lever 1a provided in the cab and an operating lever control valve 1b whose valve opening is changed in accordance with the operation of the operating lever 1a. The inlet port of the control lever control valve 1b communicates with, for example, a discharge port of a constant displacement hydraulic pump 14 via an oil passage 13. The hydraulic pump 14 is driven by the engine 6. The oil passage 13 is provided with an accumulator 19 that accumulates the pressure of the pressure oil in the oil passage 13. The oil passage 13 is provided with a pressure sensor 15 that detects the pressure of the pressure in the oil passage 13. A detection signal of the pressure sensor 15 is input to the measurement controller 30.

  The outlet port of the control valve 1b for the operation lever communicates with the pilot ports 2a and 2b of the control valve 2 via the pilot oil passages 16a and 16b.

  When the operation lever 1a is operated, the valve opening degree of the operation lever control valve 1b is changed according to the operation amount of the operation lever 1a, and the hydraulic signal Pp of the pressure corresponding to the operation amount is changed to the pilot port 2a of the control valve 2. Or it supplies to 2b and the opening area of the control valve 2 is changed according to the operation amount. In addition, pilot pressure oil is output to the pilot oil passage corresponding to the operation direction of the operation lever 1a among the pilot oil passages 16a and 16b, and the pilot pressure oil is supplied to the pilot port 2a or 2b of the control valve 2 accordingly. The valve position of the control valve 2 is changed in a direction corresponding to the operation direction of the operation lever 1a.

  For this reason, the pressure oil having a flow rate corresponding to the operation amount of the operation lever 1 a is output to the oil passage corresponding to the operation direction of the operation lever 1 a among the oil passages 11 and 12, and is passed through the oil passage 11 or 12. To the oil chamber 204B or the oil chamber 204H of the hydraulic cylinder 200. For this reason, the hydraulic cylinder 200 is driven at a direction and speed according to the operation of the operation lever 1a, and a boom, an arm, a bucket, and the like are operated at a direction and speed according to the operation.

  The battery 8 (for example, rated voltage 24V) is a power source that activates the measurement controller 30 and the control controller 20.

  A power terminal 31 of the measurement controller 30 is electrically connected to the battery 8. The power terminal 21 of the control controller 20 is electrically connected to the battery 8 via the engine key switch 9.

  When the engine key switch 9 is turned on, the battery 8 is electrically connected to a starter motor (not shown) of the engine 6 to start the engine 6 and to the power terminal 21 of the controller 20 for control. The battery 8 is electrically connected and the control controller 20 is activated. When the engine key switch 9 is turned off, the electrical connection between the power terminal 21 of the control controller 20 and the battery 8 is cut off, the engine 6 is stopped, and the control controller 20 is started and stopped. .

  A switch state signal K indicating the switch state (on / off) of the engine key switch 9 is input to the control terminal 32 of the measurement controller 30.

  A main power supply circuit 33 is provided in the measurement controller 30, and the power of the battery 8 is supplied from the power terminal 31 to the main power supply circuit 33. The measurement controller 30 stores a software timer (internal program) or an internal power supply circuit (hardware timer) as will be described later.

  When the switch state signal K input to the control terminal 32 of the measurement controller 30 is on, the drive of the main power supply circuit 33 is turned on and the measurement controller 30 is activated. When the switch state signal K is turned off, the timer is activated, and after the set time of the timer has elapsed, the drive of the main power supply circuit 33 is turned off, and the measurement controller 30 enters a start / stop state.

  Next, the configuration of FIG. 2 will be described. The description of the configuration common to FIG. 1 is omitted.

  The operation lever device 3 includes, for example, an operation lever 3a provided in a cab and a detection unit 3b that detects an operation signal St indicating an operation direction and an operation amount of the operation lever 3a. The operation signal St detected by the detection unit 3b is input to the controller 20 for control.

  The electromagnetic solenoids 4 a and 4 b of the control valve 4 are connected to the control controller 20 via the electric signal line 17.

  When the operation lever 3a is operated, the operation signal St of the operation lever 3a is input to the control controller 20, and the control controller 20 controls the operation direction of the operation lever 3a, the direction according to the operation amount, and the valve opening degree. A control signal i for operating the valve 4 is generated. The control signal i is supplied from the control controller 20 to the electromagnetic solenoid 4a or 4b of the control valve 4 via the electric signal line 17, and corresponds to the operation amount of the operation lever 3a in the direction corresponding to the operation direction of the operation lever 3a. The valve position of the control valve 4 is changed so that the opening degree of the valve is adjusted.

  The power terminal 31 of the measurement controller 30 and the power terminal 21 of the control controller 20 are electrically connected to the battery 8.

  A switch state signal K indicating the switch state (ON / OFF) of the engine key switch 9 is input to the control terminal 22 of the controller 20 for control.

  A main power supply circuit 23 is provided in the control controller 20, and the power of the battery 8 is supplied from the power terminal 21 to the main power supply circuit 23.

  The control terminal 32 of the measurement controller 30 receives information (levels 1 and 0) from the control controller 20 via the electric signal line 18 as to whether or not the hydraulic cylinder 200 described later is in an operable state. The signal J shown is input.

  A main power supply circuit 33 is provided in the measurement controller 30, and the power of the battery 8 is supplied from the power terminal 31 to the main power supply circuit 33.

  As will be described later, the level of the information signal J input to the control terminal 32 of the measurement controller 30 is monitored by software. When the information signal J is “1 level”, the main power supply circuit 33. Is turned on, and the measurement controller 30 is activated. When the information signal J becomes “0 level”, the driving of the main power supply circuit 33 is turned off, and the measurement controller 30 enters a start / stop state.

  Next, the hydraulic cylinder 200, the measurement controller 30, and the control controller 20 will be described with reference to FIG.

  As shown in FIG. 3, a hydraulic cylinder 200 is provided for each boom, arm, and bucket. Each hydraulic cylinder 200 is provided with a rotation sensor 100 that detects the stroke amount of the hydraulic cylinder 200 as a rotation amount, and a reset sensor 300 that detects the origin position of the stroke position of the hydraulic cylinder 200.

  The rotation sensor 100 and the reset sensor 300 are electrically connected to the input terminal 34 of the measurement controller 30 via the electric signal line (harness) 150 and the junction box 42.

  The measurement controller 30 includes an A / D converter 35, a storage table 36, which will be described later, and a CPU 37.

  The detection signals of the rotation sensor 100 and the reset sensor 300 are input to the input terminal 34 of the measurement controller 30 via the electric signal line 150 and the junction box 42, converted into a digital signal by the A / D converter 35, Input to the CPU 37. The CPU 37 measures the stroke position of the hydraulic cylinder 200 based on detection signals from the rotation sensor 100 and the reset sensor 300 while referring to the storage table 36 as will be described later.

  The output terminal 38 of the measurement controller 30 and the control controller 20 are connected by a signal line 43 so as to enable serial communication, and constitute an in-vehicle network. A frame signal of a predetermined protocol is transmitted to the signal line 43.

  The stroke position data of the hydraulic cylinder 200 measured by the measurement controller 30 is described in the frame signal and transmitted from the output terminal 38 to the control controller 20 via the signal line 43.

  The control controller 20 receives the data of the measured stroke position of the hydraulic cylinder 20, and the control controller 20 generates a control signal based on the acquired data of the measured stroke position of the hydraulic cylinder 20, and controls the control target. Output to the actuator (servo mechanism 7 of the hydraulic pump 5, drive mechanism 8 of the engine 6, electromagnetic solenoids 4a and 4b of the control valve 4), and controls the hydraulic pump 5, engine 6 and control valve 4.

  In the present embodiment, the controller 20 for control is shown as a single controller, but it may be divided into controllers for the hydraulic pump 5, the engine 6, and the control valve 4.

  Next, the rotation sensor 100 and the reset sensor 300 provided in the hydraulic cylinder 200 will be described.

  FIG. 4A shows the positional relationship among the hydraulic cylinder 200, the rotation sensor 100, and the magnetic force sensor 300 as a reset sensor in a longitudinal sectional view of the cylinder 200. FIG.

  As shown in FIG. 4A, a piston 201 is slidably provided on a cylinder tube 250 that is a wall of the hydraulic cylinder 200. A rod 202 is attached to the piston 201. The rod 202 is slidably provided on the cylinder head 203. A chamber defined by the cylinder head 203, the piston 201, and the cylinder inner wall constitutes a cylinder head side oil chamber 204H. An oil chamber opposite to the cylinder head side oil chamber 204H via the piston 201 constitutes a cylinder bottom side oil chamber 204B.

  The cylinder head 203 is provided with a rod seal 205a and a dust seal 205b that seal a gap with the rod 202 and prevent contamination such as dust from entering the cylinder head side oil chamber 204H.

  The cylinder tube 250 is formed with hydraulic ports 206H and 206B. Pressure oil is supplied to the cylinder head side oil chamber 204H via the hydraulic port 206H, or pressure oil is discharged from the oil chamber 204H via the hydraulic port 206H. Pressure oil is supplied to the cylinder bottom side oil chamber 204B via the hydraulic port 206B, or pressure oil is discharged from the oil chamber 204B via the hydraulic port 206B.

  When pressure oil is supplied to the cylinder head side oil chamber 204H and pressure oil is discharged from the cylinder bottom side oil chamber 204B, the rod 202 is degenerated, or pressure oil is discharged from the cylinder head side oil chamber 204H, By supplying pressure oil to the cylinder bottom side oil chamber 204B, the rod 202 extends. That is, the rod 202 moves linearly in the left-right direction in the figure.

  A case 207 that covers the rotation sensor 100 and accommodates it inside is formed outside the cylinder head side oil chamber 204H and in close contact with the cylinder head 203. The case 207 is fixed to the cylinder head 203 by being fastened to the cylinder head 203 with a bolt or the like. That is, the case 207 (the rotation sensor 100) can be easily attached to or removed from the cylinder tube 250.

  A rotation roller 110 (to be described later) constituting the rotation sensor 100 has a surface in contact with the surface of the rod 202 and is rotatably provided in accordance with the linear movement of the rod 202. That is, the rotating roller 110 converts the linear motion of the rod 202 into rotational motion.

  The rotation roller 110 is arranged such that the rotation center shaft 110c is orthogonal to the linear movement direction of the rod 202 (the rear direction of the paper, the viewer direction). The case 207 is provided with a dust seal 208 that seals a gap with the rod 202 and prevents contamination such as dust from entering between the rotating roller 110 and the rod 202. As a result, it is possible to avoid a situation in which dust or the like enters between the rotating roller 110 and the rod 202 and the rotating roller 110 malfunctions. That is, the rotation sensor 100 has a dustproof structure by the dust seal 208 provided on the case 207 and the dust seal 205 b provided on the cylinder head 203.

  The rotation sensor 100 includes at least the above-described rotation roller 110 and a rotation sensor unit 130 (FIG. 5), which will be described later, that detects the amount of rotation of the rotation roller 110. A signal indicating the amount of rotation of the rotating roller 110 detected by the rotation sensor unit 130 is sent to the measurement controller 30 via the electric signal line 150, and the position of the rod 202 of the hydraulic cylinder 200 (by the measurement controller 30 ( Stroke).

  It is inevitable that a minute slip (slip) occurs between the rotation roller 110 of the rotation sensor 100 and the rod 202, and the measurement position of the rod 202 obtained from the detection result of the rotation sensor 100 due to this slip and the rod 202. An error (cumulative error due to slipping) occurs between the actual position and the actual position. Therefore, in order to reset the measurement position obtained from the detection result of the rotation sensor 100 to the origin position (reference position), a magnetic force sensor 300 as a reset sensor is provided outside the cylinder tube 250.

  That is, the piston 201 is provided with a magnet 350 that generates lines of magnetic force. The magnet 350 is provided on the piston 201 so that the N pole and the S pole are arranged in the vertical direction in the drawing perpendicular to the linear movement direction of the piston 201 and the rod 202. The magnet 350 may be provided on the piston 201 so that the N pole and the S pole are arranged along a direction parallel to the linear movement direction of the piston 201 and the rod 202.

  The magnetic force sensor 300 includes two magnetic force sensors 301 and 302 that are spaced apart from each other by a predetermined distance along the linear movement direction of the piston 201. The magnetic sensors 301 and 302 are provided at known origin positions. The magnetic sensors 301 and 302 transmit the magnetic lines generated by the magnet 350, detect the magnetic force (magnetic flux density), and output an electric signal (voltage) corresponding to the magnetic force (magnetic flux density). The signals detected by the magnetic sensors 301 and 302 are sent to the measurement controller 30 via the electric signal line 150. The measurement controller 30 uses the rotation sensor 100 based on the detection results of the magnetic sensors 301 and 302. A process of resetting the measurement position obtained from the detection result to the origin position (reference position) is executed.

  Further, the absolute movement distance of the piston 201 and the rod 202 can be measured based on the detection positions of the two magnetic sensors 301 and 302. For example, when the rotation roller 110 of the rotation sensor 100 is consumed due to aging, the movement distance of the rod 202 obtained from the detected rotation amount of the rotation sensor 100 is smaller than the actual movement distance of the rod 202, but the piston 201 is 2 The ratio L / L ′ of the moving distance L ′ obtained from the rotation amount detected by the rotation sensor 100 when moving between the magnetic sensors 301 and 302 and the actual distance L between the two magnetic sensors 301 and 302 Based on the above, the movement distance obtained from the rotation amount detected by the rotation sensor 100 can be corrected.

  As the magnetic sensors 301 and 302, for example, Hall ICs are used.

  The magnetic sensors 301 and 302 are attached to the eaves 310. The eaves 310 are attached to the band 320. The band 320 is fixed to the outer periphery of the cylinder tube 250. The band 320 is made of a magnetic material. As a material of the band 320, a magnetic material that is usually easily available, such as a general structural steel material, can be used.

  FIG. 4B shows a cross-sectional view taken along line AA of FIG. 4A, that is, a cross-sectional view of the cylinder tube 250.

  The band 320 is fixed in pressure contact with the outer periphery of the cylinder tube 250. The band 320 includes a band member 320A having a semicircular cross section corresponding to the outer diameter of the cylinder tube 250, and a band member 320B having a semicircular cross section, and the band member 320A and the band member 320B are The cylinder tube 250 is pressed against the outer periphery by being fastened. The eaves 310 are attached to one band member 320A. For this reason, the magnetic force sensors 301 and 302 can be fixed to the outer periphery of the cylinder tube 250 without forming a screw hole in the cylinder tube 250 or performing processing such as welding the outer periphery of the cylinder tube 250. Moreover, since it is not necessary to process and process the cylinder tube 250, the thickness of the cylinder tube 250 can be maintained at a minimum thickness. That is, if the cylinder tube 250 is processed and processed, in order to maintain the strength, the tube itself must be thickened, but this is not necessary.

  In addition, the fixing position of the band 320 to the cylinder tube 250 can be easily and easily changed, and the magnetic force sensors 301 and 302 can be placed at arbitrary positions in the longitudinal direction of the cylinder tube 250 (the linear movement direction of the piston 201 and the rod 202). Can be easily and easily installed.

  Next, the configuration of the rotation sensor 100 will be described.

  As shown in FIG. 5A, the rotation sensor 100 roughly includes a rotation roller 110 provided to contact the surface of the rod 202 and rotate according to the displacement of the rod 202, as described above. The pressing member 120 presses the rotating roller 110 against the surface of the rod 202, and the rotation sensor unit 130 detects the amount of rotation of the rotating roller 110.

  The pressing member 120 includes a holder 121 and a spring 122. The holder 121 is fitted to the case 207 so as to be slidable in a direction toward the surface of the rod 202 and in a direction away from the surface. Both ends of the spring 122 are disposed between the inner wall of the case 207 and the holder 121 so that a spring force is applied in a direction in which the holder 121 faces the surface of the rod 202. The holder 121 supports the rotating shaft 111 of the rotating roller 110 through bearings 123a and 123b so as to be rotatable. FIG. 5B shows a BB cross section of FIG. As shown in FIG. 5 (b), a pin 124 is attached to the holder 121, and the pin 124 is slidably fitted to the case 207.

  Therefore, the rotating roller 110 is pressed against the surface of the rod 202 by the spring force of the spring 122.

  The rotation sensor unit 130 includes a fixed member 131, a main shaft (rotating shaft) 132, a rotating body 133, a cover 134, and a sensor member 135.

  A screw part 136 is formed around the fixing member 131, and the fixing member 131 is screwed into a screw hole 121 a formed in the holder 121. Further, the fixing member 131 is fastened to the holder 121 by a nut 140 via an O-ring 137 and a washer 138.

  The main shaft 132 is inserted into the insertion hole 131 a of the fixing member 131. The main shaft 132 is rotatably inserted into the fixed member 131 via bearings (roller bearings) 141 and 142.

  The main shaft 132 is connected to the rotating roller 110 so that the central axis 132c has the same axis as the rotating central axis of the rotating roller 110 and 110c. The main shaft 132 is coupled to the rotating roller 110 via a joint portion 143 so as to rotate integrally with the rotating roller 110.

  FIG.5 (c) has shown the coupling part 143 with sectional drawing of Fig.5 (a). As shown in FIG. 5C, the joint portion 143 includes a sleeve 144 fitted into the hole 111 a of the rotating shaft 111 of the rotating roller 110 and a tip portion 132 a having a rectangular cross section of the main shaft 132. When the distal end portion 132 a of the main shaft 132 is fitted into the sleeve 144 of the rotating roller 110, the movement of the main shaft 132 relative to the rotating roller 110 is restricted, and the main shaft 132 is integrated with the rotating roller 110. Rotate.

  The rotating body 133 is fixed by being fitted to the other end of the main shaft 132. The rotating body 133 is provided with a magnet 145 that is a detection medium. The magnet 145 rotates in accordance with the rotation of the rotating body 133, that is, the rotation of the rotating roller 110.

  The cover 134 is fixed to the fixing member 131 via the O-ring 146 by caulking so as to accommodate the rotating body 133 therein.

  The sensor member 135 is a magnetic sensor that detects a magnetic force (magnetic flux density) generated by the magnet 145 as an electric signal, and is attached to the cover 134. The sensor member 135 is provided at a position separated from the magnet 145 by a predetermined distance along the axial direction of the main shaft 132.

  The magnet 145 which is a detection medium is a mode in which the magnetic force (magnetic flux density) detected by the sensor member 135 periodically varies with one rotation of the rotating body 133, that is, one rotation of the rotating roller 110 as one cycle. The rotating body 133 is attached. A configuration example of the magnetized surface of the magnet 145 and an arrangement example of the sensor member 135 will be described later.

  A harness 150 is electrically connected to the sensor member 135. The electrical signal detected by the sensor member 135 is sent to the measurement controller 30 via the harness 150, and the electrical signal of the sensor member 135 is transmitted to the rotation amount of the rotating roller 110, that is, the cylinder 200. It is converted into the displacement amount (stroke position) of the rod 202. As the sensor member 135, for example, a Hall IC is used.

  In the present embodiment, a pair of magnets 147 and 148 are provided separately from the magnet 145 that is the detection medium.

  Of the pair of magnets 147 and 148, one magnet 147 is provided on the fixing member 131, and the other magnet 148 is provided on the side of the rotating body 133 facing the magnet 147. In addition, the magnet 145 which is a detection medium is provided on the opposite side to the side where the magnet 147 of the rotating body 133 is provided.

  The pair of magnets 147 and 148 are both formed in an annular shape, and are arranged such that the magnetized surfaces of the magnets are planes orthogonal to the central axis 132 c of the main shaft 132. The magnet 145 that is a detection medium is formed in a disk shape, and is arranged so that the magnetized surface of the magnet is a plane orthogonal to the central axis 132 c of the main shaft 132.

  The pair of magnets 147 and 148 are composed of the same poles (N poles and S poles) that generate a repulsive force. Therefore, the repulsive force between the magnets 147 and 148 having the same polarity acts on the rotating body 133 in the axial direction of the main shaft 132. The repulsive force acts on the rotating body 133 in the right direction in FIG.

  The rotating body 133 is supported by a bearing 142 as a support member against the repulsive force between the magnets 147 and 148.

  The main shaft 132 includes a large-diameter portion 132d on the rotating roller 110 side and a small-diameter portion 132e on the rotating body 133 side, and a bearing (roller bearing) 142 is provided around the small-diameter portion 132e. A repulsive force between the pair of magnets 147 and 148 acts on the rotating body 133 in the right direction in FIG. 5A, but the step between the large diameter portion 132 d and the small diameter portion 132 e of the main shaft 132 is a bearing 142. The movement of the rotating body 133 in the right direction in the figure is restricted, and the rotating body 133 is positioned at a fixed position. For this reason, the distance between the magnet 145 of the detection medium provided on the rotating body 133 and the sensor member 135 is kept constant. That is, by eliminating the backlash between the main shaft 132 and the fixing member 131, the distance between the magnet 145 as the detection medium and the sensor member 135 is kept constant.

  As described above, according to the present embodiment, the distance between the magnet 145 serving as the detection medium and the sensor member 135 is kept constant, so that the detection accuracy of the sensor member 135, that is, the rotation amount of the rotating roller 110, the displacement of the rod 202, and so on. Measurement accuracy of quantity is improved.

  By the way, the rotation sensor 100 of this embodiment is based on the assumption that the displacement of the rod 202 is converted into the rotation amount of the rotation roller 110 and the rotation sensor unit 130 detects the rotation amount. Therefore, the rotation roller 110 is not easily deformed or consumed in the radial direction, and the rotation radius is held at a constant value, so that the detection accuracy of the rotation sensor unit 130 and the displacement amount (stroke) of the rod 202 are maintained. It is necessary to improve the measurement accuracy. Further, it is necessary to increase the detection accuracy of the rotation sensor unit 130 and the measurement accuracy of the displacement amount (stroke) of the rod 202 so that the displacement of the rod 202 is faithfully converted to the rotational motion of the rotating roller 110 and does not slip.

  Therefore, in the present embodiment, as shown in FIG. 5A, at least a part 110 d (convex portion) of the rotating roller 110 that contacts the rod 2 is formed with the rotation center shaft 110 c of the rotating roller 110 and the rod. It is made of a material (e.g., S45C) that is hard enough to maintain the distance to the surface of 202 at a constant value d, and at least the other part 114 of the rotating roller 110 that contacts the rod 2 is rotated. The roller 110 and the rod 202 are made of a material (for example, an elastic member such as NBR) having a friction coefficient that is high enough to prevent slippage.

  In other words, at least a portion 114 of the rotating roller 110 that contacts the rod 2 is made of a material (elastic member such as NBR) having a higher friction coefficient than the other contact portion 110d (S45C) of the rotating roller 110. I am trying to configure it.

  That is, annular grooves 112 and 113 are formed in the circumferential direction of the rotating roller 110. Between the groove 112 and the groove 113, a convex portion 110d in which the distance from the rotation center shaft 110c to the surface of the rotation roller is set to the rotation radius d of the rotation roller 110 is configured. Here, the rotation radius d is regarded as a distance from the surface of the rod 202 to the rotation center axis 110c of the rotation roller 110, and is a parameter serving as an index for converting the rotation amount of the rotation roller 110 into a displacement amount (stroke) of the rod 202. It is. For example, the amount of linear motion of the rod 202 when the rotating roller 110 makes one rotation is calculated as 2πd using the rotation radius d.

  Tube-shaped elastic members 114 and 114 made of NBR or the like are fitted into the grooves 112 and 113 over the entire circumference. In a free state where the rotating roller 110 is not pressed against the surface of the rod 202 by the pressing member 120, the distance d1 from the rotation center shaft 110c to the outermost peripheral surface of the elastic member 114 is slightly smaller than the rotation radius d of the rotating roller 110. A large distance (d1> d) is set.

  The rotating roller 110 is pressed against the surface of the rod 202 by the spring force of the spring 122 of the pressing member 120. For this reason, in the rotating roller 110, the elastic member 114 is deformed and bent on the contact surface with the rod 202, the convex portion 110d contacts the surface of the rod 202, and the distance from the rotation center axis 110c to the surface of the rod 202 is the rotating roller. The distance is substantially the same as the rotation radius d of 110.

  Since the rotating roller 110 is pressed against the surface of the rod 202 by a spring force, a friction force corresponding to the spring force and the friction coefficient of the elastic member 114 is generated on the surface where the elastic member 114 contacts the surface of the rod 202. . Here, since the elastic member 114 has a larger coefficient of friction than the material (S45C) of the rotating roller 110 (rotating roller body), the linear motion of the rod 202 is changed to the rotating motion of the rotating roller 110 without causing a slip. Convert faithfully.

  On the other hand, the convex portion 110d also comes into contact with the surface of the rod 202 by a spring force, but the convex portion 110d is made of the material (S45C) of the rotating roller 110 (rotating roller main body), and thus is a hard and linearly moving rod. Even if pressed against the surface, it is not easily deformed or consumed in the radial direction. For this reason, the distance from the rotation center shaft 110c to the surface of the rotating roller is held at a constant value d, that is, the rotation radius d of the rotating roller 110 that is the original design value.

  For this reason, an error due to slip of the rotating roller 110 is not caused, and an arithmetic error is caused due to the actual rotating radius deviating from the designed rotating radius d due to deformation or wear of the rotating roller 110. Nothing. Thereby, the amount of linear motion (stroke) of the rod 202 is measured with extremely high accuracy.

  Next, a configuration example of the magnetized surface of the detection medium magnet 145 and an arrangement example of the sensor member 135 will be described.

  FIG. 6 shows a configuration example of the magnetized surface of the magnet 145 for the detection medium. FIG. 6 is a view of the rotating body 133 seen from the Z viewing direction (direction seen from the right side of FIG. 5A) in FIG.

  As shown in FIGS. 6A, 6 </ b> B, and 6 </ b> C, the magnet 145 is configured so that the N pole and the S pole are alternately switched according to the rotation angle of the rotating body 133. 6A is a configuration example in which the S pole and the N pole are alternately switched once, and FIG. 6B is a configuration example in which the S pole and the N pole are alternately switched twice. (C) is a configuration example in which the S pole and the N pole are alternately switched three times.

  FIG. 7A shows an arrangement example of the sensor member 135. FIG. 7 is a view of the sensor member 135 seen from the Z viewing direction (direction seen from the right side of FIG. 5A) in FIG. FIG. 7B shows an arrangement example of the sensor members 135A and 135B when the magnet 145 shown in FIG. 6A is provided. The sensor members 135A and 135B are installed so that the phases are shifted by a phase difference of 90 °. is doing. In the case of the magnet 145 shown in FIG. 6B, the sensor members 135A and 135B may be installed so as to be out of phase by a phase difference of 45 °. In the case of the magnet 145 shown in FIG. The sensor members 135A and 135B may be installed so that the phase is shifted by a phase difference of 30 °.

  As shown in FIG. 7A, the sensor member 135 is provided at a position spaced apart from the rotation center shaft 132c by a predetermined distance on the rotation surface of the rotating body 133.

  FIG. 8A illustrates the relationship between the rotation angle of the rotating roller 110 corresponding to FIG. 7A and the electrical signal (voltage) detected by the sensor member 135.

  When the rotating roller 110 rotates and the rotating body 133 mounted with the detection medium magnet 145 rotates accordingly, the magnetic force (magnetic flux density) transmitted through the sensor member 135 periodically changes according to the rotation angle. The electrical signal (voltage) changes periodically.

  The rotation angle of the rotating roller 110 can be measured from the magnitude of the voltage output from the sensor member 135.

  In FIG. 7B, the sensor members 135A and 135B are arranged on the rotation surface of the rotating body 133 at a position separated by a predetermined distance from the rotation center axis 132c with a phase shifted by a predetermined angle (for example, 90 °). Shows the case.

  FIG. 8B is a diagram corresponding to the case where the magnet 145 shown in FIG. 6A is provided and the sensor members 135A and 135B shown in FIG. 7B are provided. The relationship with the electrical signal (voltage) detected by the sensor members 135A and 135B is illustrated.

  When the rotating roller 110 rotates and the rotating body 133 mounted with the detection medium magnet 145 correspondingly rotates, the magnetic force (magnetic flux density) transmitted through the sensor members 135A and 135B changes periodically according to the rotation angle. However, the electric signal (voltage) changes periodically. When two sensor members 135A and 135B are arranged, the detection signals of the sensor members 135A and 135B are out of phase, so that not only the displacement amount of the rotation roller 110 but also the absolute angle of the rotation roller 110 is measured. be able to. Further, the rotational direction of the rotating roller 110 can also be measured.

  Further, as shown in FIG. 8C, by counting the number of times one cycle of the electrical signal (voltage) output from the sensor member 135 or the sensor members 135A and 135B is counted, the rotation number of the rotating roller 110 is set. It can be measured.

  Then, based on the rotation angle of the rotating roller 110 obtained from the detection signal shown in FIG. 8A or 8B, and the rotation number of the rotating roller 110 counted as shown in FIG. 8C. The displacement amount (stroke) of the rod 202 of the cylinder 200 is measured.

  Hereinafter, processing performed by the measurement controller 30 will be described.

(First embodiment)
In the present embodiment, as shown in FIG. 10A, it is assumed that one detection signal 400A is output from the rotation sensor 100, as in FIG. 8A.

  As described above, in this embodiment, the stroke amount sensor of the hydraulic cylinder 200 is configured by the rotation sensor 100, and the rotation sensor 100 is configured by a magnetic force sensor. In this case, there is a problem that an error is likely to occur in the measurement stroke position. In particular, when applied to a system having a large number of hydraulic cylinders 200 to be measured, such as construction machines such as hydraulic excavators, the waveform of the output signal differs for each rotation sensor 100, that is, at the same stroke position. However, there is a problem that the detected voltage value is different for each rotation sensor 100.

  That is, when the magnetic force is the detection medium, the detection signal waveform of the rotation sensor 100 is likely to be distorted due to the accuracy of the magnet 145 to be detected, the mounting error of the magnet 145, and the like. Every 100 is different. Here, even if the detected waveform of each rotation sensor 100 is uniquely regarded as a sine waveform and the output voltage of the rotation sensor 100 is converted into an engineering unit to a rotation angle using a functional expression of the sine waveform, measurement is performed by that. The rotation angle to be included includes an error due to the distortion of the waveform of the detection signal. Further, since the distortion of the waveform of the detection signal is different for each rotation sensor 100, the measured value of the rotation angle varies.

  Further, the detection level detected by the magnetic force sensor is due to the magnetization characteristics of the magnet, and is not actually a sine waveform.

  Therefore, in the first embodiment, the correspondence table between the output voltage value VA of the rotation sensor 100 and the rotation angle θA is previously stored in the storage table 36 of the measurement controller 30 as shown in FIG. When the detection signal (voltage value VA) of the rotation sensor 100 is input to the measurement controller 30, the detected voltage value VA is referenced with reference to the correspondence shown in FIG. Is obtained, and the stroke position of the hydraulic cylinder 200 is measured based on the obtained rotation angle θA.

  That is, as shown in FIG. 9A, a correspondence relationship between the output voltage value VA output from the rotation sensor 100 and the rotation angle θA of the rotation roller 110 is obtained in advance and stored in the storage table 36. .

  In this case, a correspondence relationship between the output voltage value VA and the rotation angle θA is obtained in advance for each rotation sensor 100 provided in each hydraulic cylinder 200 for the boom, arm, and bucket, and each rotation sensor for the boom, arm, and bucket is obtained. The correspondence is stored for every 100. This is because the accuracy of the magnet 145 to be detected, the mounting error of the magnet 145, and the like are different for each rotation sensor 100, and therefore the waveform of the detection signal 400A is different.

  When the detection signal 400A (voltage value VA) is input to the measurement controller 30 from the rotation sensor 100 provided in the boom hydraulic cylinder 200, as shown in FIG. As shown in (a), the correspondence relation of the rotation sensor 100 of the boom cylinder 200 is selected, the rotation angle θA corresponding to the current detected voltage value VA is read, and based on the read rotation angle θA. The stroke position of the boom hydraulic cylinder 200 is measured.

  As shown in FIG. 10A, since the waveform of the detection signal 400A of the rotation sensor 100 is sinusoidal, the rotation angle corresponding to the output voltage value VA of the rotation sensor 100 has different values θA1 and θA2. Two are read out. In this case, the rotation angle θA0 obtained last time is compared with the current rotation angle candidates θA1 and θA2, and the rotation angle (θA1) closer to the previous rotation angle θA0 may be selected.

  Similar processing is executed for the rotation sensor 100 provided in the arm hydraulic cylinder 200 and the bucket hydraulic cylinder 200.

(Second embodiment)
In the second embodiment, as shown in FIG. 10B, the two detection signals having different phases, that is, the first detection signal 400A and the second detection signal are output from the rotation sensor 100, as in FIG. 8B. Assume that the detection signal 400B is output.

  FIG. 9B is a diagram showing the storage contents of the storage table 36. A correspondence relationship between the output voltage value VA of the first detection signal 400A output from the rotation sensor 100 and the rotation angle θA of the rotation roller 110 is obtained in advance and stored in the storage table 36. Similarly, a correspondence relationship between the output voltage value VB of the second detection signal 400B output from the rotation sensor 100 and the rotation angle θB of the rotation roller 110 is obtained in advance and stored in the storage table 36.

  In this case, the correspondence relationship between the output voltage value VA and the rotation angle θA and the correspondence relationship between the output voltage value VB and the rotation angle θB are obtained in advance for each rotation sensor 100 provided in each hydraulic cylinder 200 of the boom, arm, and bucket. The correspondence relationship is stored for each rotation sensor 100 for the boom, arm, and bucket.

  When the first detection signal 400A (voltage value VA) is input to the measurement controller 30 from the rotation sensor 100 provided in the boom hydraulic cylinder 200, as shown in FIG. As shown in FIG. 9B, the correspondence relationship with respect to the first detection signal 400A of the rotation sensor 100 of the boom cylinder 200 is selected, and the rotation angle corresponding to the current detection voltage value VA (hereinafter referred to as the first detection signal 400A). (Rotation angle) θA1 and θA2 are read out. Similarly, when the second detection signal 400B (voltage value VB) is input to the measurement controller 30 from the rotation sensor 100 provided in the boom hydraulic cylinder 200, as shown in FIG. As shown in FIG. 9B, the correspondence relationship for the second detection signal 400B of the rotation sensor 100 of the boom cylinder 200 is selected from the table 36, and the rotation angle corresponding to the current detection voltage value VB (hereinafter referred to as “the detection angle value”) Second rotation angle) θB1 and θB2 are read out.

  Next, differences between the first rotation angles θA1 and θA2 and the second rotation angles θB1 and θB2, that is, θA1−θB1, θA2−θB2, θA1−θB2, and θA2−θB1 are calculated.

  Then, among these combinations of the first and second rotation angles, the combination (θA2−θB1) having the smallest difference between the two rotation angles is selected.

  Next, it is determined whether or not the difference (θA2−θB1) between the selected combinations of the first and second rotation angles is equal to or less than a predetermined value, that is, whether or not there is an abnormality in both rotation angle differences.

  When the difference between the two rotation angles is less than or equal to a predetermined value, the boom hydraulic cylinder is based on the first rotation angle (θA2) and the second rotation angle (θB1) that are less than or equal to the predetermined value. 200 stroke positions are measured. For example, the stroke position of the boom hydraulic cylinder 200 is measured using the average value of the first rotation angle (θA2) and the second rotation angle (θB1) as the current rotation angle of the rotation roller 110.

  On the other hand, when the difference between the first rotation angle and the second rotation angle is not less than the predetermined value, that is, for the combination of both rotation angles with the smallest difference (θA2−θB1), the difference is not less than the predetermined value. In this case, the rotation sensor 100 of the boom hydraulic cylinder 200 determines that an abnormality is currently occurring, and stops the measurement process.

  Similar processing is executed for the rotation sensor 100 provided in the arm hydraulic cylinder 200 and the bucket hydraulic cylinder 200.

  As described above, according to the first and second embodiments, the individual rotations input to the controller when performing the measurement process by inputting the detection signal of the rotation sensor 100 using the magnetic force as the detection medium to the controller. Even if the waveform of the sensor 100 is different, the rotation angle can be measured with high accuracy and no error by a reliable and simple method.

  Further, according to the second embodiment, the abnormality of the rotation sensor 100 can be determined based on the first and second detection signals 400A and 400B output from the rotation sensor 100, and the reliability of the measurement result can be improved. Can be improved.

  In the first embodiment and the second embodiment, the case where the rotation sensor 100 is mounted on a construction machine such as a hydraulic excavator and detects the stroke amount of the hydraulic cylinder has been described. The machine on which 100 is mounted and the detection target are arbitrary.

(Third embodiment)
By the way, in a hydraulic working machine such as a hydraulic excavator, when a long time elapses (for example, one month) even after the key switch 9 is turned off and the power is turned off after the work is finished, the working machine such as a bucket is lowered by its own weight The pressure oil remaining in the hydraulic cylinder 200 is gradually discharged, and the stroke position of the hydraulic cylinder 200 may change.

  In the hydraulic working machine, after the operation is finished, the key switch 9 is turned off and the power supply 8 is turned off.

  When the “pressure release” operation is performed, the pressure oil remaining in the hydraulic cylinder 200 is discharged even during the power-off period, and the stroke position of the hydraulic cylinder 200 changes.

  Thus, in the hydraulic working machine, the stroke position of the hydraulic cylinder 200 may change even during the power-off (engine stop) period.

  On the other hand, when the detection signal of the rotation sensor 100 is input to the measurement controller 30 and the stroke position of the hydraulic cylinder 200 is to be measured by the measurement controller 30, the position measurement process is performed when the measurement controller 30 is activated. That is, it is performed only when the power supply 8 is turned on to the measurement controller 30.

  However, if the stroke position of the hydraulic cylinder 200 changes during a power-off period other than when the measurement controller 30 is activated, the measurement controller 30 performs measurement processing based on the detection signal of the rotation sensor 100 during that time. Therefore, even if the power supply 8 is turned on again (the engine 6 is running) and the measurement controller 30 tries to start the measurement process again, the stroke position change amount during the power-off period is not known. There is a risk that it will not be possible.

  Therefore, in the third embodiment, even if the stroke position of the hydraulic cylinder 200 changes during the power-off (engine stop) period, the measurement controller 30 accurately detects the stroke based on the detection signal of the rotation sensor 100. This makes it possible to reliably measure the correct stroke position.

  11 and 12 are flowcharts showing the processing procedure of the third embodiment. FIG. 13 is a diagram for explaining stroke positions before and after power-off and on. FIG. 13 (a) is a diagram corresponding to FIG. 8 (c), showing the relationship between time, rotation angle θ, and rotation speed n, and FIG. 13 (b) is made to correspond to FIG. 13 (a). It is a figure which shows the relationship between time and stroke position S.

  In the third embodiment, as described with reference to FIG. 10A of the first embodiment, one detection signal 400A is output from the rotation sensor 100, and two rotation angles θA1, Description will be made assuming that θA2 is required.

  As shown in step 1001 of FIG. 11A, the measurement controller 30 monitors the level (ON / OFF) of the input switch state signal K, and whether or not the engine key switch 9 has been turned OFF. Is determined (step 1001).

  If it is determined that the level of the input switch state signal K is off and the engine key switch 9 is turned off (determination YES in step 1001), then whether the hydraulic cylinder 200 can be operated is checked. Based on the information on whether or not, it is determined whether or not the hydraulic cylinder 200 can be operated. An example of “information about whether the hydraulic cylinder 200 is operable” is given here, but other examples will be described later.

  For example, assuming the configuration of FIG. 1, when an OFF switch state signal K is input (determination YES in step 1001), an internal timer (software timer or hardware timer) is activated and measures time until a set time. . Here, the set time of the timer is set to a time during which the “pressure release” operation is possible, for example. That is, even if the power is turned off and the constant displacement pump 14 that supplies the original pressure to the hydraulic operation lever device 1 stops operating, the accumulator 19 is not activated for a predetermined time (for example, about 30 seconds) after the power is turned off. The operation lever device 1 is operated to supply the hydraulic pressure signal Pp to the control valve 2 to drive the control valve 2 and the pressure to operate the hydraulic cylinder 200 remains. Is possible (step 1002).

  When the timer finishes measuring the set time, it is determined that the hydraulic cylinder 200 cannot be operated. That is, it is determined that the “pressure releasing” operation is no longer possible, and that the stroke position of the hydraulic cylinder 200 is not changed by the “pressure releasing” operation (YES in step 1002). Next, the current detection signal 400A (current voltage value VA) of the rotation sensor 100 is input, and the current rotation angle candidate values θA1 ′ and θA2 ′ are stored from the storage table 36 as in the first embodiment. The current rotation angle θA0 is obtained based on these values. This rotation angle θA0 is stored in the backup memory as the old rotation angle, that is, the rotation angle θA0 when the power is turned off. If the rotational speed n of the rotating roller 110 is counted, the current rotational speed count value n is stored in the backup memory as the old rotational speed, that is, the rotational speed n when the power is turned off (step 1003).

  Next, the drive of the main power supply circuit 33 of the measurement controller 30 is turned off, and the measurement controller 30 enters a start-stop state, that is, a power-off state (step 1004).

  The main power supply circuit 33 of the measurement controller 30 is activated by the level (ON / OFF) of the switch state signal K. That is, the main power supply circuit 33 includes a logic circuit. When the engine key switch 9 is turned on or when a command signal from the software indicates “power on”, the main power circuit 33 is turned on. Is off and the command signal from the software is not “power on”, the power is turned off.

  When the main power supply circuit 33 is activated (when the power is turned on) (YES at step 1101), the old rotation angle (rotation angle when the power is turned off) θA0, the old rotation speed (the rotation number when the power is turned off) from the backup memory. ) N is read.

  Further, the current detection signal 400A (current voltage value VA) of the rotation sensor 100 is input, and the current rotation angle (θA1 in FIG. 13) is obtained as in the second embodiment (step 1102).

  That is, as illustrated in FIGS. 13A and 13B, the candidate value of the shorter stroke distance from the stroke position SA0 when the power is turned off to the candidate values SA1 and SA2 of the stroke position when the power is turned on this time. SA1 is selected as the current stroke position SA1, and the stroke position S of the hydraulic cylinder 200 is measured (step 1103).

  The stroke position measurement process in step 1103 is shown by a subroutine in FIG.

  This position measurement process is based on the premise that the rotation roller 110 of the rotation sensor 100 does not rotate from half rotation to one rotation (180 ° + α) or more before the rotation angle θA0 reaches the new rotation angle θA1. Is to be done. In step 1002 described above, the rotation angle when the “pressure release” operation that may rotate the rotating roller 110 one or more times is no longer possible is the old rotation angle θA0, and then the power is turned on. This is because the rotating roller 110 does not rotate more than one rotation until then. If the rotation roller 110 is rotated one or more times between the time when the power is turned off and the time when the power is turned off, the measurement controller 30 does not perform the process of counting the rotation speed n during that time, so the rotation speed becomes indefinite and the position measurement process is performed. Can't do it. This situation is eliminated by the processing in step 1002.

  In the following, the rightward rotation direction in FIG. 13 is the forward rotation direction, and the left rotation direction in the drawing is the reverse rotation direction.

As shown in FIG. 12, first, whether or not the value obtained by subtracting the old rotation angle θA0 from the new rotation angle θA1 is 0 ° or more, that is,
It is determined whether or not new rotation angle (θA1) −old rotation angle (θA0) ≧ 0 ° (step 1201).

If the determination in step 1201 is YES, then whether or not the value obtained by subtracting the old rotation angle θA0 from the new rotation angle θA1 is smaller than 180 ° + α, that is,
New rotation angle (θA1)-Old rotation angle (θA0) <180 ° + α
Is determined. Here, α is 0 ° <α <when the rotating roller 110 is expected to rotate in the forward rotation direction, for example, when a work machine such as a boom, an arm, or a bucket is dropped by gravity. If it is set in the range of 180 ° and reverse rotation is expected, α is set in the range of 180 ° <α <0 ° (step 1202).

  If the determination in step 1202 is YES, it is determined that the rotating roller 110 has rotated in the forward direction (step 1203).

  On the other hand, if the determination in step 1202 is NO, it is determined that the rotating roller 110 has rotated in the reverse direction (step 1204).

If the determination in step 1201 is NO, then whether or not the value obtained by subtracting the old rotation angle θA0 from the new rotation angle θA1 is larger than − (180 ° −α), that is,
New rotation angle (θA1)-Old rotation angle (θA0)>-(180 °-α)
Is determined (step 1205).

  If the determination in step 1205 is YES, it is determined that the rotating roller 110 has rotated in the reverse direction (step 1206).

  On the other hand, if the determination in step 1205 is NO, it is determined that the rotating roller 110 has rotated in the forward rotation direction (step 1207).

  Next, as a result of the above determination, the rotating roller 110 is rotated in the forward direction, the new rotation angle θA1 is smaller than 180 ° (new rotation angle (θA1) <180 °), and the old rotation angle θA0 is 180. It is determined whether or not the angle is larger than the angle (old rotation angle (θA0)> 180 °) (step 1208).

  If the determination in step 1208 is YES, it is determined that switching from 360 ° to 0 ° has occurred during the transition from the old rotation angle θA0 to the new rotation angle θA1 (FIG. 13A). The old rotation number n is incremented by +1 (assuming one rotation in the forward rotation direction) to obtain a new rotation number n (n + 1 → n) (step 1209).

  On the other hand, if the determination in step 1208 is NO, then the rotating roller 110 is rotated in the reverse direction, and the new rotation angle θA1 is greater than 180 ° (new rotation angle (θA1)> 180 °). Further, it is determined whether or not the old rotation angle θA0 is smaller than 180 ° (old rotation angle (θA0) <180 °) (step 1210).

  If the determination in step 1210 is YES, it is determined that a change from 0 ° to 360 ° occurred before the transition from the old rotation angle θA0 to the new rotation angle θA1, and the old rotation speed n is set to Incremented by −1 (assuming one rotation in the reverse direction) and set to a new number of rotations n (n−1 → n) (step 1211).

  If the determination in step 1210 is NO, the process proceeds to the next step 1212 without updating the rotation speed n. In addition, after updating the rotation speed n in steps 1209 and 1211, the process proceeds to step 1212.

  In step 1212, the stroke position S of the hydraulic cylinder 200 is calculated by the following calculation formula based on the current rotation speed n of the rotating roller 110 and the new rotation angle θA1.

S = (rotation speed n + new rotation angle (θA1) / 360 °) × rotation radius d × 2π
Here, as described above, the rotation radius d is the distance from the surface of the rod 202 to the rotation center axis 110c of the rotation roller 110 (step 1212).

  As described above, according to the third embodiment, even if the stroke position of the hydraulic cylinder 200 changes during the power-off (engine stop) period, the hydraulic cylinder 200 cannot be operated. Since the rotation speed and rotation angle are the old rotation angle and old rotation speed, the stroke position when the power is turned on again is measured based on the old rotation speed and old rotation speed. It is possible to reliably measure the stroke position without becoming unstable.

(Fourth embodiment)
In the third embodiment described above, information on whether or not the set time has elapsed since the engine key switch 9 was turned off is used as information on whether or not the operation of the hydraulic cylinder 200 has become impossible. (Step 1002), this is an example, and various other implementations are possible as listed below. In the following, with respect to the flowcharts of FIGS. 11 and 12, only portions relating to steps 1001, 1002, and 1101 will be described, and the other processing is the same as in the third embodiment, and detailed description thereof is omitted. To do.

(Another embodiment 1 of the fourth embodiment)
In the configuration of FIG. 1, information on whether or not the pressure detected by the pressure sensor 15 has become a predetermined threshold value or less may be used as information on whether or not the operation of the hydraulic cylinder 200 has become impossible. .

  That is, when the OFF switch state signal K is input (determination YES in step 1001), the detection signal of the pressure sensor 15 is input, whether or not the detected pressure has become a predetermined threshold value or less, that is, in the accumulator 19 It is determined whether or not the pressure has decreased to a pressure at which the “pressure release” operation becomes impossible (step 1002).

  If it is determined that the pressure detected by the pressure sensor 15 has become equal to or lower than a predetermined threshold value, it is determined that the hydraulic cylinder 200 can no longer operate (YES in step 1002), and the rotation at that time is determined. The rotation angle and the rotation number of the roller 110 are obtained, stored as the old rotation angle and the old rotation number (step 1003), and the measurement controller 30 is turned off (step 1004).

(Other embodiment 2 of the fourth embodiment)
In the configuration of FIG. 2, a signal J indicating whether or not the hydraulic cylinder 200 cannot be operated is input from the control controller 20 to the measurement controller 30, and the input signal J Based on the above, it may be determined whether the operation of the hydraulic cylinder 200 has become impossible.

  That is, the switch state signal K is input to the control controller 20, the level (on / off) of the switch state signal K is constantly monitored, and whether or not the engine key switch 9 is turned on / off. Is always judged.

  If it is determined by the control controller 20 that the switch state signal K has been turned off, whether a set time (a time during which a “pressure release” operation may be performed by the operation lever 3a) has elapsed from the off state. It is determined whether or not. Alternatively, the operation electric signal St input from the electric operation lever device 3 may be monitored to determine whether or not the operation lever 3a is continuously operated after being turned off.

  As described above, the control controller 20 determines whether or not the hydraulic cylinder 200 can be operated after the engine key switch 9 is turned off, and a signal indicating the determination contents (1 level, 0 level). J is generated.

  When the signal J changes to 1 level, the control controller 20 determines that the “pressure release” operation is no longer performed, and the drive of the main power supply circuit 23 of the control controller 20 is turned off, and the control controller 20 is activated. It becomes a stop state, that is, a power-off state. If the engine key switch 9 is on, the signal J is at 0 level.

  Thus, the signal J is 0 level if the hydraulic cylinder 200 can be operated regardless of whether the engine key switch 9 is on or off, that is, if the control electric signal i can be supplied to the control valve 4. When the engine key switch 9 is OFF and the hydraulic cylinder 200 cannot be operated, that is, when the control electric signal i cannot be supplied to the control valve 4, the level becomes 1 level.

In the measurement controller 30, the following processing is executed instead of steps 1001 and 1002 in FIG.
A signal J indicating whether or not the operation of the hydraulic cylinder 200 has become impossible is input from the control controller 20, and it is determined whether the level of the input signal J is 1 or 0 (step 1001). ', 1002').

  If it is determined that the level of the signal J has reached 1 level, it is determined that the operation of the hydraulic cylinder 200 has become impossible (YES in Steps 1001 ′ and 1002 ′), and the rotation angle of the rotating roller 110 at that time The rotation speed is obtained, stored as the old rotation angle and the old rotation speed (step 1003), and the measurement controller 30 is turned off (step 1004).

In the measurement controller 30, the following processing is executed instead of step 1101 in FIG.
A signal J indicating whether or not the operation of the hydraulic cylinder 200 has become impossible is input from the control controller 20, and it is determined whether the level of the input signal J is 0 or 1 (step 1101). ′).

  If it is determined that the level of the input signal J is 0 and the engine key switch 9 has been turned on (YES at step 1101 ′), the routine proceeds to the next step 1101, where the old rotation angle and the old rotation speed are determined. And a process for obtaining a new rotation angle is executed (step 1101).

  By the way, a hydraulic working machine such as a hydraulic excavator usually has a large number of work machines (boom, arm, bucket), and when each work machine is controlled based on a detection signal from a stroke position sensor, a large number of stroke positions are detected. A sensor is required. Moreover, as in each of the embodiments described above, when the stroke position is to be measured based on the detection signals of the rotation sensor 100 and the reset sensor 300, the number of sensors becomes even larger, and the calculation process is complicated and enormous. It will take a long time. Further, if it is attempted to perform complicated measurement processing based on these enormous number of sensors in the control controller 20 that must also perform processing for generating a control signal, the calculation load on the control controller 20 is as follows. , Become enormous. For this reason, it is necessary to newly develop a large-capacity control controller 20 having a high processing capacity. When a large-capacity control controller 20 having a high arithmetic processing capacity is newly developed, there arises a problem that the cost of the control system in the vehicle increases.

  In this regard, according to the present embodiment, as shown in FIG. 3, a measurement controller 30 is provided independently of the control controller 20 that generates and outputs a control signal, and the rotation sensor 100 is provided in the measurement controller 30. The detection signal of the reset sensor 300 is input, the stroke position measurement process is performed, and the measurement result is sent to the control controller 20. The control controller 20 does not need to perform the stroke position measurement process. .

  This eliminates the need to newly develop a large-capacity control controller 20 having a high processing capacity, allowing the existing control controller 20 to be used as it is, and increasing the cost of the control system inside the hydraulic work machine. Can be reduced.

  In the third and fourth embodiments, the case where the rotation sensor 100 is mounted on a construction machine such as a hydraulic excavator and detects the stroke amount of the hydraulic cylinder has been described. The machine on which 100 is mounted and the detection target are arbitrary.

(5th Example)
By the way, when the rotation sensor 100 is configured by a magnetic sensor as in the present embodiment, the signal level (voltage value) detected by the rotation sensor 100 is the temperature, other magnetic field generation source (noise), or the magnet to be detected. It may be affected by the mounting error of 145, the backlash of the rotating roller 110, and the like. For example, as shown in FIG. 14, as the temperature changes from low to high, the magnetic force is weakened, and the signal level detected by the rotation sensor 100 decreases. Therefore, if the output voltage V of the rotation sensor 100 is converted into the rotation angle θ as it is according to the data in the storage table 36, the calculated rotation is low and high, although the true rotation angle is actually the same. The angle is different, and an error occurs in the measured value of the rotation angle.

  Therefore, in the fifth embodiment, even if the detection signal level of the rotation sensor 100 using the magnetic force as a detection medium fluctuates due to the temperature or the like, the rotation angle can be measured with high accuracy and no error by a reliable and simple method. To do.

  21, 22, and 23 are flowcharts showing the processing procedure of the fifth embodiment, and FIG. 16 is an explanatory diagram of FIGS. 21, 22, and 23, and the rotation sensor 100 as in FIG. The 1st and 2nd detection signal 400A, 400B from which a phase mutually differs is output. However, in FIG. 16, for convenience of explanation, the first and second detection signals 400A and 400B shown in FIG.

  In the fifth embodiment, the reference values of the maximum peak voltage value and the minimum peak voltage value of the first and second detection signals 400A and 400B are stored in advance, and the first and second output from the rotation sensor 100 are stored. The maximum peak voltage value and the minimum peak voltage value are obtained from the respective voltage values when the detection signals 400A and 400B of the signal change for one cycle, and the obtained maximum peak voltage value, minimum peak voltage value, and stored maximum Compare the peak reference voltage value and the minimum peak reference voltage value, and the calculated maximum peak voltage value matches the stored maximum peak reference voltage value and the minimum peak voltage stored is stored The measurement controller 30 performs a process of correcting the first and second detection signals 400A and 400B output from the rotation sensor 400 so as to match the reference voltage value.

  In describing FIGS. 21, 22, 23, and 16, the meanings of symbols used in arithmetic processing are defined as follows.

A1: Address where the maximum value of the detection signal level (detection voltage value) of the first detection signal 400A is stored (hereinafter referred to as first signal maximum value variable A1)
A2: Address where the minimum value of the detection signal level (detection voltage value) of the first detection signal 400A is stored (hereinafter referred to as the first signal minimum value variable A2).
B1: Address where the maximum value of the detection signal level (detection voltage value) of the second detection signal 400B is stored (hereinafter referred to as second signal maximum value variable B1)
B2: Address where the minimum value of the detection signal level (detection voltage value) of the second detection signal 400B is stored (hereinafter referred to as second signal minimum value variable B2).
posi [0]: The address where the type of the peak that was judged to have passed this time is stored (hereinafter peak type posi [0]).
posi [1]: The address where the type of peak that was previously passed is stored (hereinafter referred to as the previous peak type posi [1])
posi [2]: Address that stores the type of peak that was determined to have passed the previous time (hereinafter referred to as the previous peak type posi [2])
AMAX; a memory for storing the maximum peak value when the value stored in the first signal maximum value variable A1 is determined to be a true maximum peak value (hereinafter referred to as a first signal maximum peak value memory AMAX). )
AMIN: Memory in which the minimum peak value is stored when it is determined that the value stored in the first signal minimum value variable A2 is the true minimum peak value (hereinafter, the first signal minimum peak value memory AMIN). )
BMAX; a memory for storing the maximum peak value when the value stored in the second signal maximum value variable B1 is determined to be the true maximum peak value (hereinafter, the second signal maximum peak value memory BMAX). )
BMIN: Memory in which the minimum peak value is stored when it is determined that the value stored in the second signal minimum value variable B2 is the true minimum peak value (hereinafter, the second signal minimum peak value memory BMIN). )

Here, the peak type is whether the peak value is the maximum peak value or the minimum peak value, and the signal having the peak value is the first detection signal 400A or the second detection signal 400B. As shown in FIG. 16, the second detection signal 400B has a maximum peak value (2), and the first detection signal 400A has a maximum peak value, as shown in FIG. There are a type (3), a peak type (4) in which the second detection signal 400B has a minimum value, and a peak type (1) in which the first detection signal 400A has a minimum value.

  Each memory AMAX, AMIN, BMAX, BMIN stores data for 10 rotations of the rotating roller 110.

  The initial values stored in the first signal maximum value variable A1 and the second signal maximum value variable B1 are set to 0V, and the first signal minimum value variable A2 and the second signal minimum value variable B2 The initial value of the stored value is set to 5V.

  When it is determined that the value stored in the first signal maximum value variable A1 is the true maximum peak value, the value stored in the first signal maximum value variable A1 is cleared to the initial value (0 V). When it is determined that the value stored in the first signal minimum value variable A2 is the true minimum peak value, the value stored in the first signal minimum variable A2 is cleared to the initial value (5V). The second signal maximum value variable B1 and the second signal minimum value variable B2 are similarly cleared.

  As shown in FIG. 21, when the process is started, it is determined whether or not the current detection voltage value of the first detection signal 400A is larger than the stored value of the first signal maximum value variable A1 (step). 1301) If the determination in step 1301 is YES, the stored value of the first signal maximum value variable A1 is updated with the current detection voltage value of the first detection signal 400A (step 1302). Control goes to step 1303. Even when the determination in step 1301 is NO, the process proceeds to step 1303.

  In step 1303, it is determined whether or not the current detection voltage value of the second detection signal 400B is larger than the stored value of the second signal maximum value variable B1 (step 1303). The determination in step 1303 is YES. In this case, the stored value of the second signal maximum value variable B1 is updated with the current detection voltage value of the second detection signal 400B (step 1304), and the process proceeds to the next step 1305. Even when the determination in step 1303 is NO, the process proceeds to step 1305.

  It is determined whether or not the current detection voltage value of the first detection signal 400A is smaller than the stored value of the first signal minimum value variable A2 (step 1305). If the determination in step 1305 is YES, The stored value of the first signal minimum value variable A2 is updated with the current detection voltage value of the first detection signal 400A (step 1306), and the process proceeds to the next step 1307. Even when the determination in step 1305 is NO, the process proceeds to step 1307.

  In step 1307, it is determined whether or not the current detection voltage value of the second detection signal 400B is smaller than the stored value of the second signal minimum value variable B2 (step 1307). The determination in step 1307 is YES. In this case, the stored value of the second signal minimum value variable B2 is updated with the current detection voltage value of the second detection signal 400B (step 1308), and the process proceeds to the next step 1309 shown in FIG. Even when the determination in step 1307 is NO, the process proceeds to step 1309.

  In step 1309, it is determined whether or not the current detection voltage value of the first detection signal 400A is the minimum peak value. For example, as shown in FIG. 16, the current detection voltage value of the first detection signal 400A is smaller than the current detection voltage value of the second detection signal 400B, and the current detection voltage of the first detection signal 400A. The above determination is made by determining whether or not the value is smaller than the threshold value C1 (step 1309).

  Next, the peak types stored in the previous peak type posi [2], the previous peak type posi [1], and the current peak type posi [0] are read out, and the previous peak type posi [2] and the previous peak type posi [ 1] and whether the contents of the current peak type posi [0] are (2), (3), (4) or (4), (3), (2), respectively (step 1310). ).

  If the determination in step 1310 is YES, as shown in FIG. 16, forward rotation ((2) → (3) → (4)) or reverse rotation (before and after the maximum peak value (peak type (3))) (4) → (3) → (2)), it is determined that the first detection signal 400A has changed by one cycle, and the value currently stored in the first signal maximum value variable A1 is true. And the current stored value of the first signal maximum value variable A1 is stored in the first signal maximum peak value memory AMAX. Further, as the stored value of the first signal maximum value variable A1 is determined to be the true maximum peak value, the stored value of the first signal maximum value variable A1 is cleared to the initial value (0V) (step S1). 1311).

  Next, it is determined whether or not the measurement controller 30 has just been turned on. Alternatively, the peak types stored in the previous peak type posi [1] and the current peak type posi [0] are read, and the contents of the previous peak type posi [1] and current peak type posi [0] are (3 ), (4) or (3), (2) is determined (step 1312).

  If it is determined that the measurement controller 30 has just been turned on, or the contents of the previous peak type posi [1] and current peak type posi [0] are (3), (4) or ( 3), if it is determined that (2), as shown in FIG. 16, the maximum peak value (peak type (3)) of the first detection signal 400A and the minimum peak of the second detection signal 400B Whether the first detection signal 400A has reached the minimum peak value (peak type (1)) via the value (peak type (4)) (in the case of normal rotation), the maximum peak value of the first detection signal 400A The first detection signal 400A becomes the minimum peak value (peak type (1)) via the (peak type (3)) and the maximum peak value (peak type (2)) of the second detection signal 400B. Judge that it is (in case of reverse) , The contents of this peak type posi [0], is updated to the peak type (3). The contents of the previous peak type posi [2] and the previous peak type posi [1] are updated by the peak types currently stored in the previous peak type posi [1] and the current peak type posi [0], respectively. (Step 1313).

  If the process in step 1313 is completed or if the determination in step 1309 is NO, the process proceeds to step 1314.

  In step 1314, it is determined whether or not the current detection voltage value of the second detection signal 400B is the minimum peak value. For example, the current detection voltage value of the second detection signal 400B is smaller than the current detection voltage value of the first detection signal 400A, and the current detection voltage value of the second detection signal 400B is the threshold value C1. The above determination is made by determining whether it is smaller than (step 1314).

  Next, the peak types stored in the previous peak type posi [2], the previous peak type posi [1], and the current peak type posi [0] are read out, and the previous peak type posi [2] and the previous peak type posi [ 1], it is determined whether the contents of the current peak type posi [0] are (1), (2), (3) or (3), (2), (1), respectively (step 1315). ).

  If the determination in step 1315 is YES, forward rotation ((1) → (2) → (3)) or reverse rotation ((3) → (2) before and after the maximum peak value (peak type (2)). (1)), it is determined that the second detection signal 400B has changed by one period, and the value currently stored in the second signal maximum value variable B1 is the true maximum peak value. Then, the current stored value of the second signal maximum value variable B1 is stored in the second signal maximum peak value memory BMAX. Further, as the stored value of the second signal maximum value variable B1 is determined to be the true maximum peak value, the stored value of the second signal maximum value variable B1 is cleared to the initial value (0V) (step S1). 1316).

  Next, it is determined whether or not the measurement controller 30 has just been turned on. Alternatively, the peak types stored in the previous peak type posi [1] and the current peak type posi [0] are read, and the contents of the previous peak type posi [1] and current peak type posi [0] are (2 ), (3) or (2), (1) is determined (step 1317).

  If it is determined that the measurement controller 30 has just been turned on, or the contents of the previous peak type posi [1] and current peak type posi [0] are (2), (3) or ( 2) When it is determined that (1), the maximum peak value of the second detection signal 400B (peak type (2)), the maximum peak value of the first detection signal 400A (peak type (3)) ), Whether the second detection signal 400B has reached the minimum peak value (peak type (4)) (in the case of normal rotation), or the maximum peak value of the second detection signal 400B (peak type (2)) The second detection signal 400B becomes the minimum peak value (peak type (4)) via the minimum peak value (peak type (1)) of the first detection signal 400A (in the case of reverse rotation). Judgment, this time peak type po The content of si [0] is updated to the peak type (4). The contents of the previous peak type posi [2] and the previous peak type posi [1] are updated by the current peak type stored in the previous peak type posi [1] and the current peak type posi [0], respectively. (Step 1318).

  If the process in step 1318 is completed or if the determination in step 1314 is NO, the process proceeds to step 1319.

  In step 1319, it is determined whether or not the current detection voltage value of the first detection signal 400A is the maximum peak value. For example, the current detection voltage value of the first detection signal 400A is larger than the current detection voltage value of the second detection signal 400A, and the current detection voltage value of the first detection signal 400A is the threshold value C2. The above determination is made by determining whether it is greater than (step 1319; see FIG. 16).

  Next, the peak types stored in the previous peak type posi [2], the previous peak type posi [1], and the current peak type posi [0] are read out, and the previous peak type posi [2] and the previous peak type posi [ 1] and whether the contents of the current peak type posi [0] are (4), (1), (2) or (2), (1), (4), respectively (step 1320). ).

  If the determination in step 1320 is YES, forward rotation ((4) → (1) → (2)) or reverse rotation ((2) → (1) before and after the minimum peak value (peak type (1)). (4)), it is determined that the first detection signal 400A has changed by one cycle, and the value currently stored in the first signal minimum value variable A2 is the true minimum peak value. Then, the current stored value of the first signal minimum value variable A2 is stored in the first signal minimum peak value memory AMIN. Further, as the stored value of the first signal minimum value variable A2 is determined to be the true minimum peak value, the stored value of the first signal minimum value variable A2 is cleared to the initial value (5V) (step S1). 1321).

  Next, it is determined whether or not the measurement controller 30 has just been turned on. Alternatively, the peak types stored in the previous peak type posi [1] and the current peak type posi [0] are read, and the contents of the previous peak type posi [1] and current peak type posi [0] are (1), respectively. ), (2) or (1), (4) is determined (step 1322).

  If it is determined that the measurement controller 30 has just been turned on, or the contents of the previous peak type posi [1] and current peak type posi [0] are (1), (2) or ( 1) When it is determined that they are (4), the minimum peak value of the first detection signal 400A (peak type (1)) and the maximum peak value of the second detection signal 400B (peak type (2)) ), Whether the first detection signal 400A has reached the maximum peak value (peak type (3)) (in the case of normal rotation), or the minimum peak value of the first detection signal 400A (peak type (1)) The first detection signal 400A becomes the maximum peak value (peak type (3)) via the minimum peak value (peak type (4)) of the second detection signal 400B (in the case of reverse rotation). Judgment, this time the peak type posi The content of [0] is updated to the peak type (3). The contents of the previous peak type posi [2] and the previous peak type posi [1] are updated by the current peak type stored in the previous peak type posi [1] and the current peak type posi [0], respectively. (Step 1323).

  If the processing in step 1323 is completed or if the determination in step 1319 is NO, the process proceeds to step 1324.

  In step 1324, it is determined whether or not the current detection voltage value of the second detection signal 400B is the maximum peak value. For example, the current detection voltage value of the second detection signal 400B is larger than the current detection voltage value of the first detection signal 400A, and the current detection voltage value of the second detection signal 400B is the threshold value C2. The above determination is made by determining whether it is greater than (step 1324; see FIG. 16).

  Next, the peak types stored in the previous peak type posi [2], the previous peak type posi [1], and the current peak type posi [0] are read out, and the previous peak type posi [2] and the previous peak type posi [ 1], it is determined whether the contents of the current peak type posi [0] are (3), (4), (1) or (1), (4), (3), respectively (step 1325). ).

  If the determination in step 1325 is YES, forward rotation ((3) → (4) → (1)) or reverse rotation ((1) → (4) before and after the minimum peak value (peak type (4)). (3)), it is determined that the second detection signal 400B has changed by one cycle, and the value currently stored in the second signal minimum value variable B2 is the true minimum peak value. Then, the current stored value of the second signal minimum value variable B2 is stored in the second signal minimum peak value memory BMIN. Further, as the stored value of the second signal minimum value variable B2 is determined to be the true minimum peak value, the stored value of the second signal minimum value variable B2 is cleared to the initial value (5V) (step S1). 1326).

  Next, it is determined whether or not the measurement controller 30 has just been turned on. Alternatively, the peak types stored in the previous peak type posi [1] and the current peak type posi [0] are read, and the contents of the previous peak type posi [1] and current peak type posi [0] are (4 ), (1) or (4), (3) is determined (step 1327).

  When it is determined that the measurement controller 30 has just been turned on, or the contents of the previous peak type posi [1] and current peak type posi [0] are (4), (1) or ( 4) When it is determined that (3), the minimum peak value of the second detection signal 400B (peak type (4)) and the minimum peak value of the first detection signal 400A (peak type (1)) ), Whether the second detection signal 400B has reached the maximum peak value (peak type (2)) (in the case of normal rotation), or the minimum peak value of the second detection signal 400B (peak type (4)) The second detection signal 400B becomes the maximum peak value (peak type (2)) via the maximum peak value (peak type (3)) of the first detection signal 400A (in the case of reverse rotation). Judgment, this time peak type po The content of si [0] is updated to the peak type (2). The contents of the previous peak type posi [2] and the previous peak type posi [1] are updated by the current peak type stored in the previous peak type posi [1] and the current peak type posi [0], respectively. (Step 1328).

  Next, from the first signal maximum peak value memory AMAX, the first signal minimum peak value memory AMIN, the second signal maximum peak value memory BMAX, and the second signal minimum peak value memory BMIN, respectively, for example, the latest 10 The stored peak value of (the latest 10 rotations of the rotating roller 110) is read out. Based on the read storage peak values, the maximum peak value and the minimum peak value of the first detection signal 400A and the maximum peak value and the minimum peak value of the second detection signal 400B are calculated. For example, the maximum peak value of the first detection signal 400 </ b> A is obtained by performing an arithmetic process that averages the last 10 stored maximum peak values stored in the first signal maximum peak value memory AMAX. The minimum peak value of the first detection signal 400A and the maximum peak value and the minimum peak value of the second detection signal 400B are obtained in the same manner (step 1329).

  Next, the maximum peak value (hereinafter referred to as the maximum peak reference voltage value) and the minimum peak value (hereinafter referred to as the minimum peak reference voltage value) of the output voltage values stored in the storage table 36 are determined in the above step 1329. The waveforms of the first and second detection signals 400A and 400B are corrected so that the peak value (hereinafter referred to as the input maximum peak value) and the minimum peak value (hereinafter referred to as the input minimum peak value) match. Specifically, the output voltage value V of the first and second detection signals 400A and 400B is corrected and converted into the output voltage value V ′ by the following arithmetic expression (1).

V ′ = (V−input minimum peak value) × (maximum peak reference value−minimum peak reference value) / (input maximum peak value−input minimum peak value) + minimum peak reference value
... (1)
The first detection signal 400A will be described as an example with reference to FIG. It is assumed that the output voltage value VA of the first detection signal 400A (at high temperature) in FIG. 14 is corrected to the output voltage value VA 'of the first detection signal 400A ′ (at low temperature). When the temperature is low, the correspondence relationship between the output voltage value VA ′ of the first detection signal 400A ′ and the rotation angle θA of the rotating roller 110 is obtained in advance and stored in the storage table 36 as in FIG. 9B. It is burned.

  The maximum peak reference value VAM ′ and the minimum peak reference value VAN ′ are read out from the output voltage value VA ′ stored in the storage table 36. Then, the above equation (1) is set so that the maximum input peak value VAM and the minimum input peak value VAN obtained in step 1329 coincide with the maximum peak reference value VAM ′ and the minimum peak reference value VAN ′. In use, the waveform of the first detection signal 400A is corrected to 400A ′. That is, in FIG. 14, the scale conversion is performed so that the waveform of the first detection signal 400A at the high temperature matches the waveform of the first detection signal 400A ′ at the low temperature.

  FIG. 15 shows the relationship between the output voltage value VA before correction and the output voltage value VA ′ after correction in the equation (1).

  As indicated by a solid line 410 in FIG. 15, the output voltage value VA is corrected to a corrected output voltage value VA ′. A straight line 420 indicated by a broken line shows an ideal relationship in which the output voltage value VA before correction matches the output voltage value VA ′ after correction.

  Although the case of correcting the first detection signal 400A has been described, the second detection signal 400B is corrected in the same manner (step 1330).

  When the corrected output voltage values VA 'and VB' are obtained as described above, the corrected output voltage value VA is stored from the storage table 36 in the same manner as described in FIG. 9B (second embodiment). ′, VB ′ (represented as VA and VB in FIG. 9B) are read out rotation angles θA and θB, and the second embodiment will be described based on the read rotation angles θA and θB. In the same manner as described above, the stroke position of the hydraulic cylinder 200 is measured.

  As described above, according to the present embodiment, even if the magnetic force is weakened as the temperature changes from low to high, and the signal level detected by the rotation sensor 100 decreases, the output voltage value V of the rotation sensor 100 is stored in the storage table. Since the correction is made so as to coincide with the output voltage value V ′ stored in 36, the rotation angle θ can be obtained equally at the low temperature and the high temperature, and the rotation angle θ can be obtained without error, and as a result, the stroke position of the hydraulic cylinder 200. Can be measured without error. As described above, according to the fifth embodiment, even if the detection signal level of the rotation sensor 100 using the magnetic force as a detection medium fluctuates due to temperature or the like, the rotation angle, The stroke position can be measured.

  In the fifth embodiment, according to the algorithm shown in FIGS. 21, 22, and 23, the first and second detection signals 400A and 400B output from the rotation sensor 100 are included in the respective voltage values when they change for one cycle. The maximum peak voltage value and the minimum peak voltage value are obtained from the above, but the algorithms shown in FIGS. 21, 22, and 23 are examples, and the present invention is not limited to these. For example, according to the positive / negative state of the other detection signal when one of the first and second detection signals 400A and 400B is at the zero cross point, the above-described peak type is (1), (2), ( The maximum peak voltage value and the minimum peak voltage value may be obtained while determining which type is 3) or (4).

  In the fifth embodiment, the voltage value at the peak point is obtained from each voltage value when the first and second detection signals 400A and 400B change by one cycle, and the obtained voltage value at the peak point is obtained. The output voltage values VA and VB of the first and second detection signals 400A and 400B are corrected so as to coincide with the reference voltage value at the peak point stored in the storage table 36. The same may be implemented by replacing the “peak point” of the first and second detection signals 400A and 400B with a “cross point”.

  That is, as shown in FIG. 16, among the cross points of the first and second detection signals 400A and 400B, the voltage value at the cross point with the positive voltage value is defined as the positive cross voltage value, and the voltage value is the negative side. If the voltage value at the cross point is a negative cross voltage value, the positive cross reference voltage value and the negative cross reference voltage value are stored in advance in the storage table 36, and the first and second detection signals of the rotation sensor 100 are stored. The positive cross voltage value and the negative cross voltage value are obtained from each voltage value when 400A and 400B change by one cycle, and the obtained positive cross voltage value and negative cross voltage value and the stored positive cross reference voltage value are obtained. The negative cross reference voltage value is compared with each other, and the first and second of the rotation sensor 100 are set so that the positive cross voltage value and the negative cross voltage value coincide with the positive cross reference voltage value and the negative cross reference voltage value, respectively. Detection signal 00A, implementation is also possible to correct the 400B.

  In the fifth embodiment, it is assumed that the first and second detection signals 400A and 400B having different phases are output from the rotation sensor 100 as shown in FIG. As shown in a), even when one type of detection signal 400A is output, correction may be performed in the same manner as in this embodiment.

  That is, as in FIG. 9A, the maximum peak reference voltage value and the minimum peak reference voltage value of the detection signal 400A are stored in advance in the storage table 36, and the detection signal 400A of the rotation sensor 100 changes by one cycle. The maximum peak voltage value and the minimum peak voltage value are obtained from the respective voltage values, and the maximum peak voltage value and the minimum peak voltage value are respectively compared with the obtained maximum peak voltage value and the minimum peak voltage value. It is also possible to correct the detection signal 400A of the rotation sensor 100 so as to match the peak reference voltage value and the minimum peak reference voltage value, respectively.

  In this embodiment, one storage table is associated with one sensor member 135 to obtain the output voltage value VA and the rotation angle θA. However, with respect to one sensor member 135, A plurality of storage tables corresponding to the maximum peak voltage and the minimum peak voltage may be associated. In this case, the storage table is selected according to the maximum peak voltage and the minimum peak voltage. An output voltage value VA and a rotation angle θA are obtained. Thereby, the correction accuracy can be further improved.

  Further, in the fifth embodiment, as shown in FIG. 15, the relationship between the output voltage value VA of the first detection signal 400A and the corrected output voltage value VA ′ is assumed to be linear, and is expressed by the above equation (1). Although correction is performed using an arithmetic expression, as shown in FIG. 17B, it is assumed that the relationship between the output voltage value VA of the first detection signal 400A and the corrected output voltage value VA 'is nonlinear. You may correct | amend using the arithmetic formula mentioned later.

  FIGS. 17A and 17B correspond to FIGS. 14 and 15, respectively.

  Assume that the waveform of the first detection signal 400A at a high temperature shown in FIG. 17A is corrected to the waveform of the first detection signal 400A ′ at a low temperature.

  The correction coefficients at the minimum peak point Pmin and the maximum peak point Pmax of the first detection signal 400A shown in FIG. 17A are obtained by the following arithmetic expressions (2) and (3).

Correction coefficient at Pmin: αmin = VAN '/ VAN (2)
Correction coefficient at Pmax; αmax = VAM ′ / VAM (3)
The voltage value VA is corrected to the voltage value VA ′ by an arithmetic expression shown in the following expression (4) using the expressions (2) and (3).

VA '= αmin + (αmax−αmin) × (VA−VAN) / (VAM−VAN)
(4)
Although the first detection signal 400A has been described, the second detection signal 400B can be similarly corrected.

  In the fifth embodiment, the rotation sensor 100 is mounted on a construction machine such as a hydraulic excavator and the stroke amount of the hydraulic cylinder is detected. However, in the present invention, the rotation sensor 100 is mounted. The machine and the detection target are arbitrary.

(Sixth embodiment)
By the way, as shown in FIG. 18A, when using the rotation sensor 100 that outputs two types of first and second detection signals 400A and 400B having different phases, different output voltages at the same time. Based on the value, the same rotation angle can be obtained.

  Since the waveforms of the first and second detection signals 400A and 400B are sinusoidal, the change in the output voltage V is small (the change in magnetic force is small) and the resolution is low with respect to the change in the rotation angle θ. In addition, there is a section in which the change in the output voltage V is large (the change in magnetic force is large) and the resolution is high with respect to the change in the rotation angle θ.

  Therefore, in this embodiment, at each time, a detection signal in a section having a high resolution is selected from the two types of first and second detection signals 400A and 400B having different phases, and a section in which the selected resolution is high. By sequentially acquiring the rotation angle θ based on the detection signal in the above, the rotation angle θ is measured accurately without error.

  FIG. 18B is a diagram illustrating processing for selecting a detection signal in a section with high resolution.

  As shown in FIG. 18B, the voltage value of the cross point where the output voltage takes a positive value at the cross point of the first and second detection signals 400A and 400B is set as the threshold value D1. .

  Then, as described below, the output voltage values of the first and second detection signals 400A and 400B are compared with the threshold value D1, and the output voltage value of the first detection signal 400A and the second detection signal are compared. The output voltage value of the signal 400B is compared, and a detection signal in a section with high resolution is selected according to the comparison result.

When the output voltage value of the second detection signal 400B is greater than or equal to the threshold value D1, and the output voltage value of the second detection signal 400B is in the section E1 greater than or equal to the output voltage value of the first detection signal 400A; One detection signal 400A is selected as a detection signal in a section with high resolution.

When the output voltage value of the first detection signal 400A exceeds the threshold value D1 and the output voltage value of the first detection signal 400A exceeds the output voltage value of the second detection signal 400B; The second detection signal 400B is selected as a detection signal in a section with high resolution.

When the output voltage value of the first detection signal 400A is equal to or less than the threshold value D1, and the output voltage value of the first detection signal 400A is in the section E3 that is equal to or greater than the output voltage value of the second detection signal 400B; One detection signal 400A is selected as a detection signal in a section with high resolution.

When the output voltage value of the second detection signal 400B is below the threshold value D1 and the output voltage value of the second detection signal 400B exceeds the output voltage value of the first detection signal 400A; The second detection signal 400B is selected as a detection signal in a section with high resolution.

  The rotation angle θ corresponding to the output voltage value V of the detection signal 400A or 400B selected as described above is read from the storage table 36 shown in FIG. 9B, and is based on the read rotation angle θ. Thus, the stroke position of the hydraulic cylinder 200 is measured.

(Seventh embodiment)
In the sixth embodiment, the detection signal is alternatively selected for each of the sections E1 to E4. For this reason, at the boundary (boundary between the section E1 and the section 2) for switching the selection from one detection signal (for example, the first detection signal 400A) to the other detection signal (the second detection signal 400B), the rotation angle θ and the stroke The position measurement value may change discontinuously.

  Therefore, weighting is performed near the boundary as shown below so that the measured values of the rotation angle θ and stroke position do not change discontinuously but change smoothly and continuously at the boundary of the section where the detection signal selection is switched. May be performed.

FIG. 19 (a) is a diagram corresponding to FIG. 18 (b), and shows the voltage values of the first and second detection signals 400A and 400B at the cross point where the output voltage takes a positive value. The threshold value D1 is set, and the voltage value at the cross point at which the output voltage takes a negative value is set as the threshold value D2. Then, in the same manner as in the sixth embodiment, the first and second detection signals The output voltage values of 400A and 400B are compared with the threshold value D1, and the output voltage value of the first detection signal 400A is compared with the output voltage value of the second detection signal 400B. Accordingly, the detection signal in the section with high resolution is selected.

  However, in the vicinity of the boundaries between the sections E1 to E4, the weighting process is performed as follows.

  FIG. 19B shows a change in the rotation angle θA measured based on the first detection signal 400A (shown by a broken line 430) and the rotation angle θB measured based on the second detection signal 400B. The change (this is indicated by the solid line 440) is shown in contrast. In FIG. 19B, there is a deviation between the rotation angles θA and θB.

  For this reason, if the second detection signal 400B is switched to the first detection signal 400B, for example, when shifting from the section E4 to the section 1 as in the sixth embodiment, the rotation angles θA and θB are The measurement value of the rotation angle θ changes discontinuously due to the deviation.

  Therefore, in the present embodiment, as shown in FIG. 19A, a transition region having a predetermined voltage width D1−ΔV to D1 + ΔV is set before and after the threshold value D1, and the transition region D1−ΔV to D1 + ΔV Thus, weighting processing is performed according to the following equation (5) to obtain the rotation angle θ.

θ = WA · θA + WB · θB (5)
However,
θA: rotation angle θB obtained from the output voltage value VA of the first detection signal 400A; rotation angle WA obtained from the output voltage value VB of the second detection signal 400B; weight of the first detection signal 400A (0% to 100%)
WB: Weight of second detection signal 400B (0% to 100%)
For example, a case where the second detection signal 400B is switched to the first detection signal 400A as in the case of shifting from the section E4 to the section E1 will be described.

  When switching from the second detection signal 400B to the first detection signal 400A, in the transition region D1-ΔV to D1 + ΔV, as the voltage value changes from D1-ΔV to D1 + ΔV, the weight WA of the first detection signal 400A. Is continuously changed from 0% to 100%. When the output voltage value is D1-ΔV, the weight WA of the first detection signal 400A is 0%, and when the output voltage value is D1 (threshold), the weight WA of the first detection signal 400A is 50%. When the output voltage value is D1 + ΔV, the weight WA of the first detection signal 400A is 100%. On the other hand, the weight WB of the second detection signal 400B is continuously changed from 100% to 0%. When the output voltage value is D1-ΔV, the weight WB of the second detection signal 400B is 100%, and when the output voltage value is D1 (threshold), the weight WB of the second detection signal 400B is 50%. When the output voltage value is D1 + ΔV, the weight WB of the second detection signal 400B is 0%.

  As a result, as shown in an enlarged view in FIG. 19 (c), when switching from the second detection signal 400B to the first detection signal 400A, the transition regions D1-ΔV to D1 + ΔV are as shown by the alternate long and short dash line 450. The rotation angle θ changes continuously. For this reason, the stroke position also changes continuously in the transition region.

  Next, a case will be described in which the first detection signal 400A is switched to the second detection signal 400B, for example, as in the case of shifting from the section E3 to the section E4.

  When switching from the first detection signal 400A to the second detection signal 400B, in the transition region D1-ΔV to D1 + ΔV, the weight WA of the first detection signal 400A increases as the voltage value changes from D1-ΔV to D1 + ΔV. Is continuously changed from 100% to 0%. When the output voltage value is D1−ΔV, the weight WA of the first detection signal 400A is 100%, and when the output voltage value is D1 (threshold), the weight WA of the first detection signal 400A is 50%. When the output voltage value is D1 + ΔV, the weight WA of the first detection signal 400A is 0%. On the other hand, the weight WB of the second detection signal 400B is continuously changed from 0% to 100%. When the output voltage value is D1-ΔV, the weight WB of the second detection signal 400B is 0%, and when the output voltage value is D1 (threshold value), the weight WB of the second detection signal 400B is 50%. When the output voltage value is D1 + ΔV, the weight WB of the second detection signal 400B is 100%.

  As a result, as shown in an enlarged view in FIG. 19D, when switching from the first detection signal 400B to the second detection signal 400B, the transition regions D1-ΔV to D1 + ΔV are as shown by the alternate long and short dash line 460. The rotation angle θ changes continuously. For this reason, the stroke position also changes continuously in the transition region.

(Eighth embodiment)
In the seventh embodiment described above, weighting processing is performed only in the vicinity of the boundary where one detection signal is switched to the other detection signal, and the measurement values of the rotation angle θ and the stroke position are continuously changed. The weighting process may be performed in all sections.

  FIGS. 20A, 20B, 20C, and 20D are diagrams illustrating arithmetic processing for obtaining weight functions wait1 and wait2 for the first and second detection signals 400A and 400B, respectively. In the following description, for convenience of explanation, the output voltage value of the first detection signal 400A is v1, the maximum peak voltage value of the first detection signal 400A is maxv1, and the minimum peak voltage of the first detection signal 400A. The value is minv1, the output voltage value of the second detection signal 400B is v2, the maximum peak voltage value of the second detection signal 400B is maxv2, and the minimum peak voltage value of the second detection signal 400B is minv2.

  That is, as shown in FIG. 20A, when the output voltage value v1 of the first detection signal 400A and the output voltage value v2 of the second detection signal 400B are input to the measurement controller 30, the following (6 ) And (7) are performed, and for each of the first and second detection signals 400A and 400B, an intermediate value in a section with high resolution, that is, an intermediate value between the maximum peak voltage value and the minimum peak voltage value. Thus, as shown in FIG. 20 (b), the first and second intermediate signals t1 and t2 that are the maximum level and have the lowest resolution, that is, the minimum level at the peak point, are obtained.

t1 = (maxv1-minv1) / 2-abs (v1- (maxv1 + minv1) / 2)
(6)
t2 = (maxv2-minv2) / 2-abs (v2- (maxv2 + minv2) / 2)
... (7)
Next, using the first and second intermediate signals t1, t2, the arithmetic processing shown in the following equations (8), (9) is performed, and for each of the first and second detection signals 400A, 400B, An intermediate value in a section with high resolution, that is, an intermediate value between the maximum peak voltage value and the minimum peak voltage value, has a maximum level of 1, and an intermediate value in a section with low resolution, that is, has a minimum level of 0 at a peak point. Second weight signals wait1 and wait2 are obtained as shown in FIG. The first and second weight signals wait1 and wait2 are adjusted to be 1 by adding both.

wait1 = t1 / (t1 + t2) (8)
wait2 = t2 / (t1 + t2) (9)
Then, as described in the seventh embodiment, the weighting process is performed according to the following equation (10), and the rotation angle θ is obtained.

θ = wait1, θA + wait2, θB (10)
However,
θA: rotation angle obtained from the output voltage value v1 of the first detection signal 400A θB: rotation angle obtained from the output voltage value v2 of the second detection signal 400B The solid line 470 shown in FIG. ) Shows the change in the rotation angle θ obtained by the equation. Further, a broken line 480 shown in FIG. 20D shows a change in the rotation angle θA obtained based only on the first detection signal 400A for comparison. The horizontal axis in FIG. 20D is the reference rotation angle, that is, the true value of the rotation angle, and the vertical axis is the measured value of the rotation angle θ.

  When the two are compared in FIG. 20D, when the rotation angle θA is obtained based only on the first detection signal 400A (broken line 480), the reference rotation angle is measured near the peak point with low resolution. When the rotation angle θ is calculated from the above equation (10) (solid line 470), the rotation angle θ is high over the entire section. It can be seen that the measurement is accurate.

  In each of the above-described embodiments, the case where a physical quantity called a voltage value is detected from the rotation sensor 100 has been described as an example. However, any physical quantity other than voltage may be used as the detected physical quantity of the rotation sensor 100.

  Further, in each of the embodiments described above, the rotation sensor 100 is provided with the rotation roller 110, and the rotation sensor 100 is mounted so that the rotation roller 110 is pressed against the rod 202 of the hydraulic cylinder 200. Although the description has been made assuming that the linear displacement of 202 is converted into a rotation amount and output as a voltage value, the configuration and mounting mode of the rotation sensor 100 are arbitrary in the present invention. For example, the rotation sensor 100 is configured such that parts necessary for pressing the rotation sensor 100 against the rod 202 such as the rotation roller 110 are omitted, and the rotation shaft 132 of the rotation sensor 100 is a rotation shaft of a boom, an arm, or a bucket of a hydraulic excavator. The present invention can also be applied to the case where the rotation sensor 100 is mounted so as to rotate together with the rotation amount of the pivot shafts of the boom, arm, and bucket and is directly output as a voltage value.

  In the third and fourth embodiments, the description has been made on the assumption that the detection medium is a magnet (magnetic force). However, the detection medium is not necessarily a magnet (magnetic force), and the stroke position of the hydraulic cylinder is determined. The detection medium is arbitrary as long as the rotation sensor detects the rotation amount. For example, the present invention according to the third and fourth embodiments can also be applied to the case where the detection medium is light and the light is detected by an optical sensor.

FIG. 1 is a diagram illustrating a hydraulic circuit of a hydraulic working machine according to an embodiment. FIG. 2 is a diagram illustrating a hydraulic circuit of the hydraulic working machine according to the embodiment. FIG. 3 is a block diagram showing the relationship between the cylinder and the controller. 4A and 4B are cross-sectional views of a cylinder tube used for explaining the relationship among the cylinder, the rotation sensor, and the reset sensor. 5A, 5B, and 5C are diagrams showing the configuration of the rotation sensor. FIGS. 6A, 6 </ b> B, and 6 </ b> C are diagrams illustrating the configuration of a magnet to be detected. 7A and 7B are diagrams illustrating the configuration of the sensor member of the rotation sensor. FIGS. 8A and 8B are graphs illustrating detection signals output from the rotation sensor. FIG. 8C is a graph corresponding to FIGS. 8A and 8B. It is the graph which showed this relationship. FIGS. 9A and 9B are diagrams illustrating the storage contents of the storage table. FIGS. 10A and 10B are diagrams corresponding to FIGS. 8A and 8B, and are diagrams for explaining processing for obtaining a rotation angle based on a storage table. FIGS. 11A and 11B are flowcharts for explaining the contents of processing performed by the measurement controller shown in FIG. 1 or FIG. FIG. 12 is a flowchart showing the subroutine processing of FIG. FIGS. 13A and 13B are diagrams used for explaining the processing shown in FIGS. 11 to 12, and are graphs showing the relationship between time and rotation angle and the relationship between time and stroke, respectively. FIG. 14 is a graph for explaining how the voltage (magnetic force) level detected by the rotation sensor changes due to a temperature change. FIG. 15 is a graph showing the relationship between the output voltage value of the rotation sensor and the corrected output voltage value. FIG. 16 is a graph used for explaining the processing contents of FIGS. 21 to 23, and is a graph showing first and second detection signals having different phases output from the rotation sensor. FIGS. 17A and 17B are diagrams corresponding to FIGS. 14 and 15 and are diagrams for explaining processing when the output voltage value and the corrected output voltage value are in a non-linear relationship. FIG. 18 (a) is a diagram pointing out a section with high resolution and a section with low resolution for the first and second detection signals output from the rotation sensor, and FIG. 18 (b). It is a figure explaining the Example which selects the detection signal in the area with high resolution among the 1st and 2nd detection signals corresponding to Fig.18 (a). 19 (a), (b), (c), and (d) are implementations in which weighting processing is performed in a transition region in which one of the first and second detection signals is switched from one detection signal to the other detection signal. It is a figure explaining an example. FIGS. 20A, 20 </ b> B, 20 </ b> C, and 20 </ b> D are diagrams illustrating an example in which weighting processing is performed in all sections. FIG. 21 is a flowchart showing a processing procedure for correcting the output voltage value of the rotation sensor to obtain the corrected output voltage value. FIG. 22 is a flowchart showing a procedure of processing for obtaining a corrected output voltage value by correcting the output voltage value of the rotation sensor. FIG. 23 is a flowchart illustrating a procedure of processing for obtaining a corrected output voltage value by correcting the output voltage value of the rotation sensor.

Explanation of symbols

  20 controller 30 measurement controller 36 storage table 100 rotation sensor 200 hydraulic cylinder 300 301, 302 magnetic force sensor (reset sensor)

Claims (3)

A rotation sensor that uses magnetic force as a detection medium, the detection physical quantity periodically changing according to the rotation angle, and a rotation sensor that outputs first and second detection signals having different phases;
The correspondence between the physical quantity detected by the rotation sensor in advance and the rotation angle is stored,
Referring to the correspondence relationship, the first and second rotation angles corresponding to the first and second detection signals are obtained, and the rotation angle is determined based on the difference between the first rotation angle and the second rotation angle. A measuring device for measuring a rotation angle. Selecting a first rotation angle and a second rotation angle at which the difference between the two rotation angles is equal to or less than a predetermined value, and measuring the rotation angle based on the selected first and second rotation angles The rotation angle measuring device according to claim 1. The rotation angle measuring device according to claim 1, wherein if the difference between the first rotation angle and the second rotation angle does not become a predetermined value or less, the rotation sensor is determined to be abnormal.

Images