JP5284837B2 - Optical encoder and method for detecting displacement of linear power transmission member - Google Patents

Description

  The present invention relates to an optical encoder that detects displacement in the longitudinal direction of a linear power transmission member such as a wire, and a displacement detection method of the linear power transmission member using the optical encoder.

  In general, in an operation system such as an endoscope and a manipulator, a drive mechanism is used that bends an operation portion by a linear power transmission member such as a wire. These operation systems need to be provided with detection means for detecting the bending angle of the operating part in order to accurately control the operation of the endoscope and manipulator.

  Patent Document 1 discloses an encoder using an optical fiber. In this encoder, light is incident on a rotating body, which is an object, from a light source via an optical fiber, and the amount of light reflected from the rotating body to the optical fiber is detected. Thereby, the rotation position and rotation direction of the rotating body are detected.

  Patent Document 2 discloses an optical fiber type detection sensor that detects a bending angle of an endoscope. In this detection sensor, a plurality of light absorbing portions are formed in the optical fiber, and the amount of light absorbed by the light absorbing portion is detected. Since the amount of light absorbed by the light absorption unit changes depending on the bending angle of the operation portion of the endoscope, the bending angle of the operation portion of the endoscope is detected by detecting the amount of light absorbed by the light absorption portion. It is like that.

JP 2000-18971 A Japanese Patent No. 4005318

  For example, in the case of an operation system for a treatment apparatus having an outer diameter of 10 mm or less, such as a medical manipulator, it is difficult to dispose angle sensors such as conventional potentiometers and encoders in the operating portion of a thin manipulator.

  Even if the angle sensor can be miniaturized and the angle sensor can be arranged in the operating part, if the manipulator has multiple joints with multiple degrees of freedom, the bending angle is detected for the operating part corresponding to each joint part. It is necessary to provide an angle sensor for this purpose. For this reason, the number of angle sensors increases, and the number of wires connected to each angle sensor also increases. It is difficult to insert many wires into the gaps inside the thin manipulator.

  The medical manipulator is a wire driving mechanism that operates by moving the wire in the longitudinal direction. However, the encoder of Patent Document 1 detects the rotational position and rotational information of the rotating body, and is used for linear power such as a wire. It does not detect the displacement of the transmission member.

  In the detection sensor of Patent Document 2, the amount of light absorbed by the light absorbing portion that changes depending on the bending angle is detected, and the bending angle is calculated from the detected light amount. For this reason, it is greatly affected by variations in the amount of light emitted from the light source.

  The present invention has been made by paying attention to the above-mentioned problems. The object of the present invention is to realize an encoder and a linear device that achieve miniaturization and simplification of the configuration, and have high detection accuracy of the displacement of the linear power transmission member. The object is to provide a displacement detection method for a power transmission member.

In order to achieve the above object, an optical encoder according to an aspect of the present invention includes a linear power transmission member that moves in a longitudinal direction, an outer peripheral surface of the linear power transmission member, and the linear power transmission member. A reflector that can move in the longitudinal direction integrally with the member, has a slit portion in which two kinds of reflecting portions having different reflectivities are arranged in a predetermined pattern in the longitudinal direction, and can be bent integrally with the linear power transmission member A light source that emits light, a linear light transmission body that guides light from the light source to the slit portion and that reflects reflected light from the slit portion, the linear power transmission member, and the reflection The body is held so as to be movable in the longitudinal direction, and light is incident on the slit portion from a direction perpendicular to the longitudinal direction of the linear power transmission member, and the light is reflected from the slit portion. Light is going A holding member having an incident / reflective path formed therein, wherein light can be incident on the slit through the light incident / reflective path, and light reflected from the slit through the light incident / reflected path is guided. A holding member that holds the linear light transmission body at a position where light can be transmitted, and an electric light that receives the reflected light from the slit portion guided from the linear light transmission body, and indicates the displacement and light quantity of the reflection body. A light receiving element for detecting a signal, signal processing means for converting the electric signal into a pulse signal having a predetermined threshold value, and calculating means for calculating a displacement in the longitudinal direction of the reflector from the number of pulses of the pulse signal. It is characterized by providing.
Further, another certain displacement detection method of linear power transmission member of the embodiment of the present invention, is held by a linear power transmission member and the holding member in a movable state in the longitudinal direction together, the linear power transmission Light is incident from a light source through a linear optical transmission body into a slit portion provided in a reflector that can be bent integrally with a member and arranged in a predetermined pattern in the longitudinal direction with two kinds of reflection portions having different reflectivities. The light guided by the linear light transmission body is perpendicular to the slit direction from the direction perpendicular to the longitudinal direction of the linear power transmission member. Including a step of entering the slit portion through a light incident / reflecting passage, and a step of guiding reflected light reflected by the slit portion to the linear optical transmission body and receiving the light by a light receiving element, the slit Reflected light from the front An electric signal indicating a displacement and a light amount of the reflector by the light receiving element, and a step including a step of directing the reflected light passing through the light incident / reflecting path toward the light incident / reflecting path by the linear optical transmission body Detecting the signal, converting the electrical signal into a pulse signal having a predetermined threshold by the signal processing means, calculating the displacement in the longitudinal direction of the reflector from the number of pulses of the pulse signal by the calculating means, It is characterized by providing.

  ADVANTAGE OF THE INVENTION According to this invention, while realizing size reduction and simplification of a structure, the encoder and the displacement detection method of a linear power transmission member with high detection accuracy of the displacement of a linear power transmission member can be provided.

FIG. 1 is a block diagram illustrating a bending operation system for a manipulator including an optical encoder according to a first embodiment of the present invention. FIG. 2 is a perspective view illustrating a configuration of an encoder ring unit according to the first embodiment. FIG. 3 is a perspective view illustrating a configuration of an encoder head unit according to the first embodiment. FIG. 4 is a longitudinal sectional view showing the configuration of the encoder head unit according to the first embodiment. 5 is a cross-sectional view taken along line VV in FIG. FIG. 6 is a perspective view illustrating a configuration of an encoder slit portion according to the first embodiment. FIG. 7 is a cross-sectional view illustrating the configuration of the encoder slit portion according to the first embodiment. 8A is a view of FIG. 7 viewed from the direction of arrow A, FIG. 8B is a view viewed from the direction of arrow B, and FIG. 8C is a view viewed from the direction of arrow Z. FIG. FIG. 9 is a flowchart illustrating the operation of the optical encoder according to the first embodiment. FIG. 10 is a graph showing an electrical signal of the first slit part, (B) is a graph showing an electrical signal of the second slit part, detected by the light receiving element according to the first embodiment. (C) is a graph which shows the electrical signal of a 3rd slit part. 11A is a graph showing the pulse signal of the electrical signal of FIG. 10A, FIG. 11B is a graph showing the pulse signal of the electrical signal of FIG. 10B, and FIG. The graph which shows the pulse signal of the electrical signal of). 12A and 12B are longitudinal sectional views showing a state where the operating portion of the manipulator according to the first embodiment is not bent, and FIG. 12B is a longitudinal sectional view showing a bent state. FIG. 13 is a perspective view illustrating a configuration of an encoder slit portion according to a first modification of the first embodiment. FIG. 14 is a longitudinal sectional view showing a configuration of an encoder slit portion according to a first modification of the first embodiment. FIG. 15 is a perspective view illustrating a configuration of an encoder slit portion according to a second modification of the first embodiment. FIG. 16 is a cross-sectional view showing a configuration of an encoder head unit according to a second modification of the first embodiment. FIG. 17 is a perspective view illustrating a configuration of an encoder slit portion according to a third modification of the first embodiment. FIG. 18 is a cross-sectional view illustrating a configuration of an encoder head unit according to a third modification of the first embodiment. FIG. 19 is a longitudinal sectional view showing a configuration of an encoder head unit according to a fourth modification of the first embodiment. FIG. 20 is a longitudinal sectional view showing a configuration of an encoder head unit according to a fifth modification of the first embodiment. FIG. 21 is a transverse cross-sectional view showing a configuration of an encoder head unit according to a sixth modification of the first embodiment.

  A first embodiment of the present invention will be described with reference to FIGS. 1 to 12A and 12B.

  FIG. 1 is a diagram illustrating a bending operation system of a manipulator 1 including the optical encoder of the present embodiment. As shown in FIG. 1, the manipulator 1 includes an elongated tubular portion 2 and an operation portion 3 provided on the distal end side of the tubular portion 2. Four wires 5, which are linear power transmission members, are inserted into the tubular portion 2 of the manipulator 1 and connected to the operating portion 3. Of the four wires 5, two wires 5 are connected to the upper part and the lower part of the operation unit 3. These two wires 5 are used for the bending operation in the vertical direction. The other two wires 5 are connected to the left part and the right part of the operation part 3. These two wires 5 are used for the bending operation in the left-right direction. The proximal end portion of the wire 5 is connected to driving means 11 provided outside the manipulator 1. The driving means 11 is a combination of a rotary motor and a pulley, or a linear motor, and the wire 5 is connected to each motor, or the upper and lower wires 5 and the left and right wires 5 are integrated into the pulley. It is rolled up. The drive unit 11 is connected to a control unit 12 such as a computer. The control means 12 is connected to an operation means 13 such as a joystick or a handle, and an image display means 14 such as a display. The image display means 14 displays an image of a camera (not shown) provided at the tip of the manipulator.

  When bending the operation unit 3, the surgeon operates the operation unit 13 in a direction in which the operation unit 3 is bent while viewing an image displayed on the image display unit 14. A signal input to the operation means 13 is sent to the control means 12. In the control unit 12, predetermined calculation is performed so as to correspond to the operation of the operation unit 3, and the displacement of the motor of the drive unit 11 that drives the operation unit 3 is calculated. The calculated displacement of the motor of the driving unit 11 is sent to the driving unit 11 as a signal. In the drive means 11, the signal from the control means 12 is converted into a current signal for driving the motor, and the motor is driven. When the motor of the driving unit 11 is driven, the wire 5 connected to the operation unit 3 is pushed out toward the distal end or pulled toward the proximal end. For example, when the operation unit 3 of the manipulator 1 is bent upward, the wire 5 connected to the upper part of the operation unit 3 is pulled toward the proximal end, and the wire 5 connected to the lower part of the operation unit 3 is It is pushed out to the tip side. As described above, the bending angle of the operating portion 3 of the manipulator 1 changes in the vertical direction and the horizontal direction.

  As shown in FIG. 1, a cylindrical encoder ring portion 20 constituting an optical encoder is disposed in the vicinity of the operation portion 3 inside the tubular portion 2 of the manipulator 1. FIG. 2 is a diagram illustrating a configuration of the encoder ring unit 20. As shown in FIG. 2, the encoder ring portion 20 is provided with a number of cylindrical slot portions 23 penetrating the encoder ring portion 20 in the longitudinal direction corresponding to the number of wires 5 (four in this embodiment). . The four slot portions 23 are disposed substantially concentrically at positions separated from each other by approximately 90 ° in the circumferential direction of the encoder ring portion 20. In each slot part 23, the encoder head part 21 is stored in a fixed state. The encoder head unit 21 detects the displacement amount of each wire 5, the displacement moving direction, and the displacement amount from the reference position.

  3 to 5 are diagrams showing the configuration of one encoder head unit 21. FIG. As shown in FIGS. 3 to 5, a cylindrical center hole 31 penetrating the encoder head portion 21 in the longitudinal direction is formed at the axial center of the encoder head portion 21. A cylindrical encoder slit portion 32 as a reflector is fixed to the outer peripheral surface of the wire 5 with a certain length in the longitudinal direction. That is, the wire 5 is inserted into the encoder slit portion 32 in a state of being fixed to the inner peripheral surface. A wire 5 and an encoder slit portion 32 are inserted into the center hole 31 so as to be reciprocally movable in the longitudinal direction. In the center hole 31 of the encoder head portion 21, the wire 5 and the encoder slit portion 32 are integrally movable in the longitudinal direction with respect to the encoder head portion 21. With such a configuration, the wire 5 and the encoder slit portion 32 are held movably in the longitudinal direction by the encoder head portion 21 which is a holding member.

  6A to 8C are views showing the configuration of the encoder slit portion 32. FIG. As shown by a two-dot chain line in FIG. 7, the circumference of the encoder slit portion 32 is divided into three reading areas every 120 °. As shown in FIGS. 5 and 7, a first slit portion 40A, a second slit portion 40B, and a third slit portion 40Z are formed in the three divided portions, respectively. That is, the slit portions 40A, 40B, and 40Z are formed with a phase difference of 120 ° with the slit portions 40A, 40B, and 40Z adjacent to the outer peripheral surface of the encoder slit portion 32 in the direction around the axis.

  FIG. 8A shows the first slit portion 40A, and FIG. 8B shows the second slit portion 40B. As shown in FIGS. 8A and 8B, in the first slit portion 40A and the second slit portion 40B, two types of reflecting portions 41A and 41B having different reflectances are arranged in a predetermined pattern in the longitudinal direction. A phase and B phase are formed. Of the two types of reflection parts 41A and 41B, one having a high reflectance is a first reflection part 41A, and the other is a second reflection part 41B. In the first slit portion 40 </ b> A, the first reflecting portions 41 </ b> A and the second reflecting portions 41 </ b> B are alternately arranged with a certain width along the longitudinal direction of the encoder slit portion 32. In the second slit portion 40B, the first reflective portion 41A and the second reflective portion 41B have the same width as the first slit portion 40A along the longitudinal direction of the encoder slit portion 32, and the first slit portion 40B The slit portions 40A are alternately arranged with a predetermined distance shifted in the longitudinal direction. The second slit detected by the light receiving element of the optical means 16, which will be described later, by shifting the arrangement of the reflecting portions 41A, 41B in the second slit portion 40B by a predetermined distance from the first slit portion 40A in the longitudinal direction. The electrical signal from the portion 40B and the electrical signal from the first slit portion 40A have a phase difference of 90 °.

  FIG. 8C shows the third slit portion 40Z. As shown in FIG. 8C, in the third slit portion 40Z, the Z-phase in which the first reflecting portion 41A is arranged on one side and the second reflecting portion 41B is arranged on the other side with the reference position 42 as a boundary. Is formed.

  The slit portions 40A, 40B, and 40Z are formed by providing, for example, a portion that is processed by laser processing, cutting, photolithography, coating agent application, laser printing, and the like and a portion that is not processed on the outer peripheral surface of the encoder slit portion 32. Is done. Thereby, since light is scattered in the processed portion, the second reflective portion 41B having a low reflectivity to the optical fiber 22 is formed, and the non-processed portion is the first reflective portion 41A having a high reflectivity to the optical fiber 22. . Moreover, you may form slit part 40A, 40B, 40Z by providing the part printed by printing etc. in the outer peripheral surface of the encoder slit part 32, and the part which is not printed. In this case, the printed portion is the second reflecting portion 41B having a low reflectance to the optical fiber 22, and the non-printing portion is the first reflecting portion 41A having a high reflectance to the optical fiber 22.

  The encoder slit portion 32 is preferably formed of a flexible member such as a SUS pipe. As a result, when the wire 5 is bent, the encoder slit portion 32 can also be bent integrally with the wire.

  As shown in FIG. 3, three optical fiber holes 35 are formed around the center hole 31 on the base end surface of the encoder head portion 21. The three optical fiber holes 35 are arranged substantially concentrically from the center hole 31 at positions corresponding to the slit portions 40A, 40B, and 40Z in the direction around the axis. As shown in FIG. 4, the optical fiber hole 35 is formed in parallel with the center hole 31 along the longitudinal direction from the base end face of the encoder head portion 21. Further, as shown in FIG. 5, the encoder head portion 21 has light incident / reflecting holes 37 penetrating from the tip end portion of the optical fiber hole 35 to the center hole 31 as the light transmitting portions, respectively, in the slit portions 40A, 40B, 40Z. It is formed perpendicular to. A prism 36 serving as an optical path conversion member is provided between the optical fiber hole 35 and the light incident / reflecting hole 37. In each optical fiber hole 35, an optical fiber 22, which is a linear optical transmission body that guides light to each slit portion 40 </ b> A, 40 </ b> B, 40 </ b> Z of the encoder slit portion 32, is inserted in parallel with the wire 5. That is, the optical fiber 22 is held in parallel with the wire 5 at a position away from the wire 5 by the encoder head portion 21 which is a holding member.

  The proximal end portion of the optical fiber 22 is connected to the encoder signal processing unit 15 outside the manipulator 1. The encoder signal processing unit 15 includes an optical unit 16 that receives light incident on the optical fiber 22 and receives reflected light from the encoder head unit 21 using an optical element such as a light source, a lens, and a light receiving element, and a signal processing circuit. Signal processing means 17.

  With this configuration, the light emitted from the light source of the optical means 16 is guided to the prism 36 by the optical fiber 22. The prism 36 includes, for example, an incident / exit surface formed at an angle of 90 ° so as to face the slit portion 32 and each optical fiber 22 in parallel as shown in the figure, and passes through these incident / exit surfaces. And a reflecting surface for forming an optical path along which the light beam reciprocating. Then, it is bent by 90 ° by the prism 36 and enters the slit portions 40A, 40B, and 40Z from the light incident / reflecting hole 37. The reflected light reflected by the slit portions 40A, 40B, and 40Z passes through the light incident / reflecting hole 37 and is bent by 90 ° by the prism 36 to be guided to the optical fiber 22. Then, it passes through the optical fiber 22 and is received by the light receiving element of the optical means 16. That is, the optical fiber 22 is held by the encoder head portion 21 at a position where light can be incident on the slit portions 40A, 40B, and 40Z and reflected light from the slit portions 40A, 40B, and 40Z can be guided. . At this time, since the light incident / reflecting holes 37 are formed perpendicular to the slit portions 40A, 40B, 40Z, incident light incident on the slit portions 40A, 40B, 40Z enters the light incident / reflecting holes 37. It is designed to reflect toward you.

  The reflected light received by the light receiving element of the optical means 16 is converted into an electrical signal. The electrical signal converted by the light receiving element is sent to the signal processing means 17. The signal processing means 17 performs signal processing such as waveform processing and signal pulsing. The encoder output signal from the signal processing means 17 is sent to the control means 12. A calculation means (not shown) provided in the control means 12 calculates the displacement amount of the wire 5, the movement direction of the displacement, and the movement amount from the reference position. Based on the calculated information, the difference between the target displacement and the actual displacement is calculated, and the motor of the driving means 11 is driven and controlled.

  Next, the operation of the optical encoder of this embodiment will be described. FIG. 9 is a diagram illustrating the operation of the optical encoder. As shown in FIG. 9, in the optical encoder, the light emitted from the light source of the optical means 16 is guided to the prism 36 by the optical fiber 22. Then, it is bent by 90 ° by the prism 36, and enters the slit portions 40A, 40B, and 40Z from the light incident / reflecting hole 37 (step S101). The reflected light reflected by the slit portions 40A, 40B, and 40Z passes through the light incident / reflecting hole 37 and is bent by 90 ° by the prism 36 to be guided to the optical fiber 22. Then, the light is received by the light receiving element of the optical means 16 through the optical fiber 22 (step S102).

  Moreover, when changing the bending angle of the action | operation part 3 of the manipulator 1, it is performed by moving the wire 5 which is a linear power transmission member to a longitudinal direction. At this time, the encoder slit portion 32 which is a reflector fixed to the outer peripheral surface of the wire 5 also moves in the longitudinal direction integrally with the wire 5. Since the encoder slit portion 32 is provided with two types of reflection portions 41A and 41B having different reflectivities, the first reflection portion 41A and the second reflection portion 41B receive the same amount of light. However, the amount of light received by the light receiving element of the optical means 16 is different. Therefore, by the movement of the encoder slit portion 32 in the longitudinal direction, an electrical signal having a waveform indicating the displacement and the amount of light of the encoder slit portion 32 as shown in FIGS. 10A to 10C is detected (step S103). Here, FIG. 10A shows a waveform detected from the first slit portion 40A. FIG. 10B shows a waveform detected from the second slit portion 40B, and has a 90 ° phase difference from the waveform detected from the first slit portion 40A. FIG. 10C shows a waveform detected from the third slit portion 40Z. Since the wire 5 and the encoder slit portion 32 are held by the encoder head portion 21 that is a holding member, the optical path length from the light source of the optical means 16 to the slit portions 40A, 40B, and 40Z is the longitudinal length of the encoder slit portion 32. It is substantially constant regardless of the displacement in the direction. Thereby, stable detection is possible.

  A waveform signal indicating the displacement and the amount of light is sent from the light receiving element to the signal processing means 17. The signal processing means 17 performs signal processing such as signal waveform processing and pulsing. 10A to 10C is converted into a pulse signal with a threshold value t1 as shown in FIGS. 11A to 11C by signal processing (step S104), and the calculation means of the control means 12 is sent to the calculation means. Sent. Then, from the number of pulses of the pulse signal from the first slit portion 40A and the dimensions of the first reflecting portion 41A and the second reflecting portion 41B of the known first slit portion 40A, the displacement amount of the encoder slit portion 32 is determined. Calculated (step S105). Further, the displacement moving direction of the encoder slit portion 32 is calculated from the pulse number of the pulse signal from the first slit portion 40A and the pulse number of the pulse signal from the second slit portion 40B (step S105). Further, the amount of movement from the reference position is calculated from the number of pulses of the pulse signal from the third slit portion 40Z (step S105). Since the wire 5 moves integrally with the encoder slit portion 32 in the longitudinal direction, the displacement amount in the longitudinal direction of the encoder slit portion 32, the moving direction of the displacement, and the movement amount from the reference position are caused by this movement. The displacement amount in the direction, the displacement movement direction, and the displacement amount from the reference position.

  Then, the bending displacement, that is, the bending angle of the operating portion 3 is calculated from the calculated displacement amount of the wire 5. There are various methods for calculating the bending angle of the operation unit 3 from the displacement amount of the wire 5, but one method is to actually change the displacement amount of the wire 5 and measure the bending angle of the operation unit 3, and the relationship. An equation is derived or a table is prepared, and when the movement amount of the wire is detected by the optical fiber encoder, the bending angle of the operation unit 3 is calculated by applying the equation to the relational equation or the table.

  Another method will be described with reference to FIG. FIGS. 12A and 12B are cross-sectional views showing the operation unit 3 of the manipulator 1. As shown in FIG. 12A, there is a wire attachment position P1 where the wire 5 is attached near the tip of the operating portion 3. The operating portion 3 has a bending start position P2 that is the most proximal side of the portion that bends when the wire 5 is pulled. Let L be the length on the central axis C between the wire attachment position P1 and the bending start position P2. Further, the length in the radial direction from the central axis C to the wire attachment position P1 is r. As shown in FIG. 1 (B), when one wire 5 is pulled by Δx length and the other wire 5 is pushed by Δx, the curvature of the bent portion is the same at any position. In this case, the length of L is not different from the case of not bending as shown in FIG. At this time, the relationship of the movement amount Δx of the wire 5 with respect to the angle θ between the bending start position P2 and the wire attachment position P1 can be obtained by θ = Δx / r.

  Here, the case of either one of the upper and lower bends or the left and right bends has been described. However, the above equation holds even when the upper and lower and right and left bends are simultaneously bent.

  Therefore, the optical encoder configured as described above has the following effects. That is, in the optical encoder, light is incident on the slit portions 40A, 40B, and 40Z in which two kinds of reflection portions 41A and 41B having different reflectances are arranged in a predetermined pattern in the longitudinal direction (step S101), and the slit portion 40A , 40B and 40Z, the reflected light is received by the light receiving element (step S102). Since the amount of light guided to the optical fiber 22 is different between the first reflecting portion 41A and the second reflecting portion 41B, when the encoder slit portion 32 moves in the longitudinal direction integrally with the wire 5, the light receiving element of the optical means 16 Thus, an electrical signal having a waveform indicating the displacement of the encoder slit portion 32 and the amount of light is detected (step S103). Then, it is converted into a pulse signal having a specific threshold value by the signal processing means 17 (step S104), and the number of pulses of the pulse signal detected by the calculation means of the control means 12 and the first reflection part 41A of the known encoder slit part 32 are detected. The displacement amount of the encoder slit portion 32, the displacement moving direction, and the displacement amount from the reference position are calculated from the dimensions of the second reflecting portion 41B (step S105). Since the wire 5 moves in the longitudinal direction integrally with the encoder slit portion 32, the displacement in the longitudinal direction of the wire 5 is accurately detected from the displacement amount of the encoder slit portion 32, the displacement movement direction, and the movement amount from the reference position. be able to.

  In the optical encoder, since the light is guided to the slit portions 40A, 40B, and 40Z by the optical fiber 22, the optical encoder is reduced in size. Thereby, the encoder head part 21 which hold | maintains the encoder slit part 32 can be accommodated in the small diameter tubular shape of front-end | tip parts, such as a manipulator and an endoscope.

  In addition, since no electrical component is provided in the encoder head portion 21, it is not necessary to provide a plurality of wires connected to the electrical component, and the influence of electrical noise is reduced during detection. Thereby, simplification of the configuration of the optical encoder can be realized, and sterilization, washing, and the like can be easily performed.

  Further, in the optical encoder, the optical fiber 22 is held in parallel with the wire 5 by the encoder head portion 21 that is a holding member, and a prism 36 is provided between the tip of the optical fiber 22 and the light incident reflection hole 37. ing. Light emitted from the light source is guided to the prism 36 by the optical fiber 22. Then, it is bent by 90 ° by the prism 36 and enters the slit portions 40A, 40B, and 40Z from the light incident / reflecting hole 37. The reflected light reflected by the slit portions 40A, 40B, and 40Z passes through the light incident / reflecting hole 37 and is bent by 90 ° by the prism 36 to be guided to the optical fiber 22. Then, it passes through the optical fiber 22 and is received by the light receiving element of the optical means 16. By providing the prism 36, the optical fiber 22 is not curved at a position where light can be incident on the slit portions 40A, 40B, and 40Z and reflected light from the slit portions 40A, 40B, and 40Z can be guided. Be placed. Thereby, the encoder head part 21 can be further reduced in size. At this time, since the light incident / reflecting holes 37 are formed perpendicular to the respective slit portions 40A, 40B, 40Z, incident light incident on the slit portions 40A, 40B, 40Z enters the light incident / reflecting holes 37. It is designed to reflect toward you. For this reason, detection accuracy can be improved.

  Next, first to third modifications of the first embodiment of the present invention will be described with reference to FIGS. 13 to 18. In the first to third modifications, the configuration of the first embodiment is modified as follows. In addition, the same code | symbol is attached | subjected about the part same as 1st Embodiment, and the description is abbreviate | omitted.

  13 and 14 are diagrams showing the configuration of the encoder slit portion 61 of the first modification. As shown in FIGS. 13 and 14, the encoder slit 61 is formed in a cylindrical shape. The wire 5 is not inserted into the encoder slit portion 61, and the wire 5 is fixed to both ends of the encoder slit portion 61.

  FIG. 15 is a diagram illustrating a configuration of the encoder slit portion 62 of the second modification. As shown in FIG. 15, the encoder slit portion 62 is formed in a quadrangular prism shape. The encoder slit portion 62 is formed with a wire insertion hole 63 penetrating the encoder slit portion 62 in the longitudinal direction, and the wire 5 is inserted in a fixed state into the wire insertion hole 63. On any three surfaces of the four surfaces parallel to the longitudinal direction of the encoder slit portion 62, A-phase, B-phase, and Z-phase slit portions 40A, 40B, and 40Z are formed.

  FIG. 16 is a diagram illustrating a configuration of the encoder head unit 64 that holds the encoder slit unit 62. As shown in FIG. 16, a square columnar center hole 65 is formed at the axial center of the encoder head portion 64, and the encoder slit portion 62 and the wire 5 are inserted through the center hole 65. Similar to the encoder head portion 21, the encoder head portion 64 is provided with three optical fiber holes 35, a prism 36, and a light incident / reflecting hole 37. The optical fiber hole 35 is disposed at a position corresponding to each of the slit portions 40 </ b> A, 40 </ b> B, 40 </ b> Z in the direction around the axis, and the optical fiber 22 is inserted in parallel with the wire 5. The light incident / reflecting hole 37 is formed perpendicular to the three surfaces on which the slit portions 40A, 40B, and 40Z of the encoder slit portion 62 are formed. With such a configuration, light is incident perpendicular to the surface of the encoder slit portion 62 where the slit portions 40A, 40B, and 40Z are formed.

  FIG. 17 is a diagram illustrating a configuration of the encoder slit portion 66 of the third modification. As shown in FIG. 17, the encoder slit part 66 is formed in a triangular prism shape. The encoder slit portion 66 is formed with a wire insertion hole 67 penetrating the encoder slit portion 66 in the longitudinal direction. The wire insertion hole 67 is inserted in a state where the wire 5 is fixed. A-phase, B-phase, and Z-phase slit portions 40A, 40B, and 40Z are formed on three surfaces parallel to the longitudinal direction of the encoder slit portion 66.

  FIG. 18 is a diagram illustrating a configuration of the encoder head portion 68 that holds the encoder slit portion 66. As shown in FIG. 18, a triangular prism-shaped center hole 69 is formed at the axial center of the encoder head portion 68, and the encoder slit portion 66 and the wire 5 are inserted through the center hole 69. Similar to the encoder head portion 21, the encoder head portion 68 is provided with three optical fiber holes 35, a prism 36, and a light incident / reflecting hole 37. The optical fiber hole 35 is disposed at a position corresponding to each of the slit portions 40 </ b> A, 40 </ b> B, 40 </ b> Z in the direction around the axis, and the optical fiber 22 is inserted in parallel with the wire 5. The light incident / reflecting hole 37 is formed perpendicular to the three surfaces on which the slit portions 40A, 40B, and 40Z of the encoder slit portion 62 are formed. With such a configuration, light is incident perpendicular to the surface of the encoder slit portion 62 where the slit portions 40A, 40B, and 40Z are formed.

  As described above, as shown in the first to third modifications, in this embodiment, the wire 5 and the encoder slit portion are held by the encoder head portion that is a holding member, and the wire 5 and the encoder head portion are integrally formed in the longitudinal direction. Any movable configuration may be used.

  Next, the 4th and 5th modification of the 1st Embodiment of this invention is demonstrated with reference to FIG.19 and FIG.20. In the fourth modification, the configuration of the first embodiment is modified as follows. In addition, the same code | symbol is attached | subjected about the part same as 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 19 is a diagram illustrating a configuration of an encoder head unit 71 according to a fourth modification. As shown in FIG. 19, in the encoder head portion 71, a mirror 72 is used as an optical path conversion member. The light emitted from the light source of the optical means 16 is guided to the mirror 72 by the optical fiber 22. Then, it is bent 90 ° by the mirror 72 and enters the slit portions 40A, 40B, and 40Z from the light incident / reflecting hole 37. The reflected light reflected by the slit portions 40A, 40B, and 40Z passes through the light incident / reflecting hole 37, and is guided to the optical fiber 22 by being bent by 90 ° by the mirror 72. Then, it passes through the optical fiber 22 and is received by the light receiving element of the optical means 16. That is, the optical fiber 22 is held by the encoder head portion 71 at a position where light can be incident on the slit portions 40A, 40B, and 40Z and reflected light from the slit portions 40A, 40B, and 40Z can be guided. . At this time, since the light incident / reflecting holes 37 are formed perpendicular to the slit portions 40A, 40B, 40Z, incident light incident on the slit portions 40A, 40B, 40Z enters the light incident / reflecting holes 37. It is designed to reflect toward you.

  FIG. 20 is a diagram illustrating a configuration of an encoder head unit 73 according to a fifth modification. As shown in FIG. 20, in the encoder head portion 73, an optical fiber 74 that guides light to the slit portions 40 </ b> A, 40 </ b> B, and 40 </ b> Z passes through the optical fiber hole 35 from the base end surface of the encoder head portion 73. It is curved at the tip of 35 and inserted up to the light incident / reflecting hole 37. The optical fiber 74 is inserted perpendicularly to the slits 40A, 40B, and 40Z into the held portion 75 held in parallel with the wire 5 in the optical fiber hole 35 by the encoder head portion 73 and the light incident / reflecting hole 37. A light incident / reflecting portion 76, and a curved portion 77 provided between the held portion 75 and the light incident / reflecting portion 76. The curved portion 77 of the optical fiber 74 serves as an optical path conversion unit that can convert the optical path of light within the tube. The light emitted from the light source of the optical means 16 passes through the held portion 75 of the optical fiber 74 and is guided to the bending portion 77. Then, the optical path is converted by the bending portion 77 and enters the slit portions 40A, 40B, and 40Z from the light incident / reflecting portion 76. The reflected light reflected by the slit portions 40 </ b> A, 40 </ b> B, and 40 </ b> Z passes through the light incident / reflecting portion 76 and is guided to the held portion 75 by changing the optical path at the bending portion 77. Then, the light is received by the light receiving element of the optical means 16. That is, the optical fiber 74 is held by the encoder head portion 73 at a position where light can be incident on the slit portions 40A, 40B, and 40Z and reflected light from the slit portions 40A, 40B, and 40Z can be guided. .

  By adopting such a configuration, the light incident / reflecting part 76 is formed perpendicular to the respective slit parts 40A, 40B, 40Z, so that incident light incident on the slit parts 40A, 40B, 40Z is The light is reflected toward the light incident / reflecting portion 76. Further, since no optical path conversion member such as the prism 36 and the mirror 72 is used, attenuation of the light amount at the optical path conversion member is prevented. For this reason, detection accuracy can be improved.

  Next, a sixth modification of the first embodiment of the present invention will be described with reference to FIG. In the sixth modification, the configuration of the first embodiment is changed as follows. In addition, the same code | symbol is attached | subjected about the part same as 1st Embodiment, and the description is abbreviate | omitted.

  FIG. 21 is a diagram illustrating a configuration of an encoder head unit 80 according to a sixth modification. As shown in FIG. 21, a cylindrical encoder slit hole 81 is formed in the center of the encoder head 80, and the encoder slit 82 and the wire 5 are inserted into the encoder slit hole 81. . The encoder slit portion 82 is provided with three projecting portions 83 projecting outward from the outer peripheral surface. The cross-sectional shape cut by a cross section perpendicular to the longitudinal direction of the protrusion 83 is a quadrangular shape. In the encoder slit portion hole 81 of the encoder head portion 80, three groove portions 84 having a shape corresponding to the protruding portion 83 of the encoder slit portion 82 are formed at positions corresponding to the protruding portion 83 in the direction around the axis. By engaging the protruding portion 83 as the engaging portion with the groove portion 84 as the engaged portion, movement of the encoder slit portion 82 and the wire 5 in the direction around the axis with respect to the encoder head portion 80 can be restricted. At this time, the encoder slit portion 82 and the wire 5 are movable with respect to the encoder head portion 80 in the longitudinal direction.

In the present embodiment, three protrusions 83 are provided, but one or more protrusions 83 may be formed on the outer peripheral surface of the encoder slit part 82. Moreover, the cross-sectional shape cut | disconnected by the cross section perpendicular | vertical with respect to the longitudinal direction of the protrusion part 83 is not restricted to square shape, For example, triangle shape etc. may be sufficient.
In the above-described embodiment, the encoder slit portion 32 is formed with three types of slit portions 40A, 40B, and 40Z. However, a configuration in which only one type or two types of slit portions are formed may be used. It is good also as four or more types. In this case, the displacement in the longitudinal direction of the wire 5 may be calculated using the pulse signals of one type, two types, or four or more types of slit portions. Further, in the cylindrical encoder slit portion 32, only the circumferential portion corresponding to the portion corresponding to the slit portions 40A, 40B and 40Z and corresponding to the region where the reflected light can be guided to the respective light incident reflection holes 37 is partially provided. As in the second and third modifications, a plane perpendicular to the light incident / reflecting hole 37 may be formed along the longitudinal direction.

  Further, in the above-described embodiment, the first slit portion is set so that the phase difference between the electrical signal detected from the second slit portion 40B and the electrical signal detected from the first slit portion 40A is 90 °. In 40A and the second slit portion 40B, the arrangement patterns in the longitudinal direction of the first reflecting portion 41A and the second reflecting portion 41B are different, but the first slit portion 40A and the second slit portion 40B are different in the first slit portion 40B. The arrangement pattern in the longitudinal direction of the first reflecting portion 41A and the second reflecting portion 41B may be the same, and the light incident / reflecting holes 37 that allow light to enter the slit portions 40A and 40B may be shifted in the longitudinal direction. .

  Further, an optical means such as a convex lens or a ball lens that makes light incident on the slit portions 40A, 40B, and 40Z parallel to the light incident / reflecting hole 37 may be disposed.

  Furthermore, although this embodiment demonstrated the manipulator 1 using an optical encoder, if it is a case where the displacement to the longitudinal direction of a linear power transmission member is detected, it will not restrict to this.

  The embodiments of the present invention have been described above. However, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Manipulator, 2 ... Tubular part, 3 ... Operation | movement part, 5 ... Wire, 11 ... Driving means, 12 ... Control means, 15 ... Encoder signal processing part, 16 ... Optical means, 17 ... Signal processing means, 20 ... Encoder ring Reference numeral 21: Encoder head part 22: Optical fiber 32: Encoder slit part 36: Prism 37: Light incident / reflection hole 40A, 40B, 40Z: Slit part 41A, 41B: Reflector part

Claims (6)

A linear power transmission member that moves in the longitudinal direction;
The linear power transmission member is fixed to the outer peripheral surface, and can be moved integrally with the linear power transmission member in the longitudinal direction, and two kinds of reflecting portions having different reflectances are arranged in a predetermined pattern in the longitudinal direction. A reflector that can be bent integrally with the linear power transmission member ;
A light source that emits light;
A linear optical transmission body that guides light from the light source to the slit portion and guides reflected light reflected from the slit portion;
The linear power transmission member and the reflector are held movably in the longitudinal direction, and light is incident on the slit portion from a direction perpendicular to the longitudinal direction of the linear power transmission member. In addition, a holding member in which an incident / reflection path to which reflected light from the slit portion is directed is formed, and light can be incident on the slit portion through the light incident / reflection path, and the light incident / reflection path. A holding member that holds the linear optical transmission body at a position where the reflected light from the slit portion that has passed through can be guided;
A light receiving element that receives reflected light at the slit portion guided from the linear light transmission body and detects an electrical signal indicating the displacement and the amount of light of the reflector;
Signal processing means for converting the electrical signal into a pulse signal having a predetermined threshold;
Calculating means for calculating displacement in the longitudinal direction of the reflector from the number of pulses of the pulse signal;
An optical encoder comprising: In the reflector, a plurality of types of the slit portions are arranged in parallel along the circumferential direction of the outer peripheral surface,
Each of the slit portions is set in a state in which the arrangement pattern in the longitudinal direction of the two types of the reflection portions is different,
The optical encoder according to claim 1, wherein the linear optical transmission body and the light incident / reflection path are provided for each of the slit portions. The plurality of types of slit portions are
Two types of the reflection portions, the first slit portions alternately arranged with a certain width along the longitudinal direction,
The two types of the reflective portions are alternately arranged along the longitudinal direction with the same width as the first slit portion and shifted from the first slit portion by a predetermined distance in the longitudinal direction. 2 slits,
A third slit portion in which one of the two types of the reflection portion is disposed on the distal end side with the predetermined reference position as a boundary, and the other is disposed on the proximal end side;
The optical encoder according to claim 2, wherein: The reflector is provided with an engaging portion of at least one of a concave portion and a convex portion in a part of the outer peripheral surface in the circumferential direction,
Wherein the holding member is configured to engage with the engaging portion, the optical according to claim 1, characterized in that the engaged portion that restricts the movement in the axial direction around the reflector is provided Type encoder. The holding member is disposed in an axial center portion, and is formed perpendicular to the center hole into which the reflector is inserted, and the slit portion of the reflector, and is provided with the light incident / reflection passage. And comprising
The linear optical transmission body is held in parallel with the linear power transmission member by the holding member,
2. The optical encoder according to claim 1, wherein an optical path conversion unit that converts an optical path of light is provided between a tip of the linear optical transmission body and the light transmission unit. Two types of reflections with different reflectivities , which are held by a holding member while being movable in the longitudinal direction integrally with the linear power transmission member and provided on a reflector that can be bent integrally with the linear power transmission member. The light is incident from the light source through the linear light transmitter to the slit portion in which the portions are arranged in a predetermined pattern in the longitudinal direction, and the light guided by the linear light transmitter is And entering the slit part through a light incident / reflection path inside the holding member perpendicularly to the slit part from a direction perpendicular to the longitudinal direction of the power transmission member;
The step of guiding the reflected light reflected by the slit part to the linear optical transmission body and receiving it by a light receiving element, wherein the reflected light from the slit part goes to the light incident / reflecting path, and the light incident / reflected A step including the reflected light passing through the passage is guided by the linear light transmitter;
Detecting an electrical signal indicating the displacement and light quantity of the reflector with the light receiving element;
Converting the electrical signal into a pulse signal having a predetermined threshold by a signal processing means;
Calculating a displacement in the longitudinal direction of the reflector from the number of pulses of the pulse signal by a calculating means;
A displacement detection method for a linear power transmission member.

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