A nuclear magnetic resonance compatible rotary encoder

Abstract

The invention discloses a nuclear magnetic compatible rotary encoder, comprising a fixed seat, a sensing cylinder, a laser generator, a sensing module and a transmission shaft; a rotating cavity is provided on the fixed seat, and two groups of symmetrically arranged output through holes and input through holes are provided around the axis of the rotating cavity, and the output through holes and the input through holes are communicated with the rotating cavity; a cross groove is provided at one end of the sensing cylinder, and the cross groove comprises a first channel and a second channel which are cross-arranged and communicate with each other with their centers overlapping; the sensing cylinder is rotatably installed in the rotating cavity, and the cross groove extends into a range surrounded by the output through hole and the input through hole; the first channel and the second channel are respectively used for optically connecting the two groups of symmetrically arranged output through holes and the input through holes; the laser generator is optically connected to the output through hole, and the sensing module is optically connected to the input through hole; the sequence of connecting the first channel and the second channel to the two groups of output through holes and the input through hole is used to judge the rotation direction of the sensing cylinder; and the transmission shaft is transmission connected to the other end of the sensing cylinder.

Description

Technical Field

[0001] The present invention relates to the technical field of rotary encoders, and particularly to a nuclear magnetic resonance compatible rotary encoder. Background Art

[0002] In clinical medicine, nuclear magnetic resonance (NMR) and CT (Computed Tomography) are used for the examination of multiple organs. Compared with CT, the principle of NMR is relatively simple. Although the appearance of the equipment is very similar to that of CT, it has no radiation and is very safe for patients, their families and doctors.

[0003] Nuclear magnetic resonance imaging technology has the advantages of no radiation, high resolution, excellent tissue contrast, large imaging space, etc. Therefore, when it is applied in surgery, doctors can comprehensively evaluate the important anatomical relationship between the intervention target and adjacent tissues. During the operation, it can be scanned and monitored at any time, which is convenient for real-time observation of the intraoperative situation and greatly improves the work efficiency. In addition, because NMR has no radiation, it will not cause harm to the physical health of doctors and can effectively protect the surgical staff.

[0004] The motor is a component that provides the required torque and rotational motion in the joints of a surgical robot. However, in the strong magnetic field environment generated by the NMR scanner, motors made of ferromagnetic materials and controlled based on electrical signals cannot be used. Currently, some surgical robots that can be used in the NMR environment use pneumatic motors to perform the functions of motors and provide the required torque and rotational motion for the joints of the surgical robot.

[0005] For a pneumatic motor, its rotational speed and direction are very important state information. Only by accurately monitoring the rotational speed and direction of the pneumatic motor can the motion of the pneumatic motor be accurately controlled, and the surgical robot can be controlled to perform precise surgical operations. Among them, the rotational speed and direction need to be measured by corresponding sensors. Similarly, sensors made of ferromagnetic materials and controlled based on electrical signals cannot be used in the NMR environment due to electromagnetic interference, so the state information of the pneumatic motor cannot be measured.

[0006] Therefore, there is an urgent need for a sensor that can be used in the NMR environment and is highly compatible with the pneumatic motor. Summary of the Invention

[0007] The purpose of the present invention is to provide a nuclear magnetic resonance compatible rotary encoder to solve the problem that sensors made of existing ferromagnetic materials and controlled based on electrical signals cannot be used in the NMR environment.

[0008] To solve the above technical problems, the present invention provides a nuclear magnetic compatible rotary encoder, which includes a fixed seat, an induction cylinder, a laser generator, an induction module and a transmission shaft; a rotating cavity is provided on the fixed seat, and two sets of symmetrically arranged output through holes and input through holes are arranged around the axis of the rotating cavity, and the output through holes and the input through holes communicate with the rotating cavity; one end of the induction cylinder is provided with a cross groove, and the cross groove includes a first channel and a second channel that are cross-arranged and centrally coincident and communicated; the induction cylinder is rotatably installed in the rotating cavity, and the cross groove extends into the range surrounded by the output through holes and the input through holes; the first channel and the second channel are respectively used for optically connecting two sets of symmetrically arranged output through holes and input through holes; the laser generator is optically connected to the output through holes, and the induction module is optically connected to the input through holes; the sequence of connection between the first channel and the second channel and the two sets of output through holes and input through holes is used to judge the rotation direction of the induction cylinder; the periodic change of the connection between the first channel or the second channel and the two sets of output through holes and input through holes is used to measure the rotation speed of the induction cylinder; the transmission shaft is drivingly connected to the other end of the induction cylinder.

[0009] In one embodiment, the included angle between the symmetry center lines of the length directions of the first channel and the second channel is 27°-45°.

[0010] In one embodiment, a retaining wall is provided between the first channel and the second channel on the outer circle of the induction cylinder.

[0011] In one embodiment, the rotary encoder further includes optical fiber lines; the optical fiber lines are inserted into both sets of the output through holes and the input through holes, and multiple optical fiber lines are respectively optically connected to the laser generator and the induction module.

[0012] In one embodiment, the rotary encoder further includes optical fiber connectors; multiple optical fiber lines are respectively inserted into multiple optical fiber connectors, and multiple optical fiber connectors are respectively optically connected to the corresponding laser generator and induction module.

[0013] In one embodiment, the induction module is a photosensitive resistor module, and the photosensitive resistor module is optically connected to the optical fiber connector.

[0014] In one embodiment, the rotary encoder further includes a housing; the housing is provided with multiple wire holes; the optical fiber connectors, the laser generator and the induction module are all installed in the housing, and the optical fiber lines pass through the wire holes.

[0015] In one embodiment, a plastic bearing is further installed in the rotating cavity; the rotating cavity is in the shape of a stepped cylinder; the induction cylinder and the plastic bearing are installed in the rotating cavity in sequence from the inside to the outside; the outer ring of the plastic bearing is fixedly connected to the rotating cavity, and the induction cylinder is fixedly connected to the inner ring of the plastic bearing.

[0016] In one embodiment, the materials used for manufacturing the fixed seat, the induction cylinder, the optical fiber line and the transmission shaft are all polylactic acid.

[0017] The beneficial effects of the present invention are as follows:

[0018] 1. The sensor can realize displacement-optical-electric conversion-digital conversion; through the laser generator, the induction module and the optical fiber line, the mechanical geometric displacement amount on the induction cylinder can be converted into a pulse digital quantity. By measuring the light passing through the first channel and the second channel, observing the level and phase difference of its output, it can be judged the rotation speed and direction of the induction cylinder, and then the state data of the pneumatic motor connected to the induction cylinder can be obtained.

[0019] 2. One end of the transmission shaft is connected to the induction cylinder through a plastic bearing. The transmission shaft can be connected to any pneumatic motor, with high adaptability to the pneumatic motor and convenient use.

[0020] 3. The induction cylinder, the transmission shaft and the plastic bearing all adopt 3D printing technology, which can be applied to MRI surgery, is not affected by the magnetic field, can accurately measure the rotation speed and direction of the pneumatic motor, and hardly affects the image quality at the same time. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0022] Figure 1 is the overall structural schematic diagram of the present invention;

[0023] Figure 2 is the perspective structural schematic diagram of the fixed seat of the present invention;

[0024] Figure 3 is the structural schematic diagram of the induction cylinder of the present invention;

[0025] Figure 4 is the assembly schematic diagram of the present invention;

[0026] Figure 5 is Figure 4Partial enlarged schematic view of the unassembled fixing base in part A;

[0027] Figure 6 is an exploded view of the overall structure schematic of the present invention;

[0028] Figure 7 is a schematic view of the included angle between the first channel and the second channel of the present invention being 45°;

[0029] Figure 8 is the output signal diagram of the induction cylinder of the present invention rotating clockwise;

[0030] Figure 9 is the output signal diagram of the induction cylinder of the present invention rotating counterclockwise.

[0031] The reference numerals are as follows:

[0032] 1, fixing base; 11, rotating cavity; 12, output through hole; 13, input through hole;

[0033] 2, induction cylinder; 21, cross slot; 211, first channel; 212, second channel; 22, retaining wall;

[0034] 3, laser generator;

[0035] 4, induction module;

[0036] 5, transmission shaft;

[0037] 6, optical fiber cable;

[0038] 7, optical fiber connector;

[0039] 8, plastic bearing;

[0040] 9, housing; 91, wire hole. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention.

[0042] An embodiment of the rotary encoder is as follows Figures 1 to 6As shown, it includes a fixing base 1, a sensing cylinder 2, a laser generator 3, a sensing module 4 and a transmission shaft 5; a rotating cavity 11 is provided on the fixing base 1, and two groups of symmetrically arranged output through holes 12 and input through holes 13 are provided around the axis of the rotating cavity 11, and the output through holes 12 and the input through holes 13 are connected to the rotating cavity 11; a cross groove 21 is provided at one end of the sensing cylinder 2, and the cross groove 21 includes a first channel 211 and a second channel 212 that are cross-arranged and centrally overlapped and communicated; the sensing cylinder 2 is rotatably installed in the rotating cavity 11, and the cross groove 21 extends into the range surrounded by the output through hole 12 and the input through hole 13; the first channel The first channel 211 and the second channel 212 are respectively used to optically connect the two groups of symmetrically arranged output through holes 12 and input through holes 13; the laser generator 3 is optically connected to the output through holes 12, and the sensing module 4 is optically connected to the input through holes 13; the sequence of the first channel 211 and the second channel 212 connecting to the two groups of output through holes 12 and the input through holes 13 is used to determine the rotation direction of the sensing cylinder 2; the periodic change of the first channel 211 or the second channel 212 connecting to the two groups of output through holes 12 and the input through holes 13 is used to measure the rotation speed of the sensing cylinder 2; the transmission shaft 5 is drivingly connected to the other end of the sensing cylinder 2.

[0043] When in use, one end of the transmission shaft 5 can be connected to the power supply using a coupling, and the other end of the transmission shaft 5 is connected to the pin hole at the other end of the induction cylinder 2, such as Figure 6 shown.

[0044] Principle of judging the direction of rotation: By observing the phase difference of the output levels of the two groups of optical fiber lines 6, the direction of rotation of the sensing cylinder 2, that is, the pneumatic motor connected to the transmission shaft 5, can be judged.

[0045] Principle of judging rotation speed: The rotation speed is measured by observing the changes in a set of input and output signals. When the output end of one set of optical fiber lines 6 outputs four high levels and four low levels, that is, the induction cylinder 2 rotates one circle, the rotation speed of the pneumatic motor connected to the transmission shaft 5 can be measured.

[0046] Regarding the angle between the first channel 211 and the second channel 212, the angle between the longitudinal symmetric center lines of the first channel 211 and the second channel 212 is 27°-45°.

[0047] When applied, the first channel 211 and the second channel 212 form a certain angle, the purpose of which is to produce a phase difference between the optical fiber signals passing through the two channels, and the rotation direction can be determined based on the phase difference.

[0048] In addition, as shown in FIG3 , in this embodiment, a retaining wall 22 is provided between the first channel 211 and the second channel 212 on the outer ring of the sensing cylinder 2. The retaining wall 22 is conducive to separating the first channel 211 and the second channel 212, so as to achieve the purpose of measuring the steering.

[0049] Regarding the above-mentioned optical connection between the laser generator 3 and the output through hole 12 and the optical connection between the sensing module 4 and the input through hole 13, this embodiment is as follows: Figures 1 to 6 As shown, the rotary encoder further includes an optical fiber line 6; the optical fiber lines 6 are inserted into both the two groups of output through holes 12 and the input through holes 13, and the multiple optical fiber lines 6 are optically connected to the laser generator 3 and the sensing module 4 respectively. The rotary encoder further includes an optical fiber connector 7; the multiple optical fiber lines 6 are respectively inserted into the multiple optical fiber connectors 7, and the multiple optical fiber connectors 7 are optically connected to the corresponding laser generator 3 and the sensing module 4 respectively.

[0050] When applied, there are two output through holes 12 and two input through holes 13, one output through hole 12 and one input through hole 13 form a group, corresponding to sensing one channel; by setting two groups of output through holes 12 and input through holes 13, corresponding sensing is performed on the first channel 211 and the second channel 212; by installing an optical fiber line 6 on each output through hole 12 and input through hole 13, the optical fiber line 6 provides a channel for light to pass through, and the output through hole 12 and the input through hole 13 are respectively connected to the corresponding laser generator 3 and the sensing module 4 through the optical fiber line 6, thereby completing the optical connection between the output through hole 12 and the input through hole 13 and the corresponding components.

[0051] In order to realize the light sensing function, the sensing module 4 is a photoresistor module, and the photoresistor module is optically connected to the optical fiber connector 7 .

[0052] The light from the laser generator 3 is transmitted to the photoresistor module at the signal processing end through the optical fiber line 6 and the optical fiber connector 7 after passing through the cross slot 21, and the optical signal is converted into an electrical signal.

[0053] Furthermore, in order to protect the optical fiber connector 7, the laser generator 3 and the sensing module 4, this embodiment Figure 1 , Figure 4 and Figure 6 As shown, the rotary encoder further includes a housing 9; the housing 9 is provided with a plurality of wire holes 91;

[0054] The optical fiber connector 7 , the laser generator 3 and the sensing module 4 are all installed in the housing 9 , and the optical fiber line 6 passes through the line hole 91 .

[0055] When in use, the optical fiber connector 7 is assembled with the laser generator 3 and the sensing module 4 and installed in the housing 9. Then the optical fiber connector 7 is connected to the optical fiber line 6. The optical fiber line 6 passes through the wire hole 91 and out of the housing 9. Multiple optical fiber lines 6 are then inserted into the output through hole 12 and the input through hole 13 respectively, thereby completing the connection of the optical transmission link.

[0056] Regarding the specific structure of the sensing cylinder 2 being rotatably installed in the rotating chamber 11, this embodiment Figure 2 , Figure 5and Figure 6 As shown in the figure, a plastic bearing 8 is also installed in the rotating cavity 11; the shape of the rotating cavity 11 is a stepped cylinder; an induction cylinder 2 and a plastic bearing 8 are installed in the rotating cavity 11 from the inside to the outside in sequence; the outer ring of the plastic bearing 8 is fixedly connected to the rotating cavity 11, and the induction cylinder 2 is fixedly connected to the inner ring of the plastic bearing 8. The materials used for manufacturing the fixed seat 1, the induction cylinder 2, the optical fiber line 6 and the transmission shaft 5 are all polylactic acid.

[0057] Specifically, the plastic bearing 8 adopts 3D printing technology, which can achieve rapid manufacturing; in addition, the induction cylinder 2 and the transmission shaft 5 are also manufactured by 3D printing technology, so as to realize the rapid additive manufacturing of key components, making it possible for rapid deployment during application. And polylactic acid is a new type of biodegradable material, using renewable plant resources, and is a recognized environmentally friendly material, very suitable for 3D printing molding, and it has good mechanical properties, very suitable for manufacturing light-load mechanical parts.

[0058] It should be noted that this rotary encoder innovatively judges the rotation direction of the pneumatic motor by measuring the phase of the output level of the optical fiber line 6. As Figures 7 to 9 shown in the figure, when high levels are received at both output ends, it can be known that the light at the input ends ④ and ⑤ passes through the corresponding channels to ⑥ and ⑦ at the same time. Due to the design of the angle between the channels of the induction cylinder 2, the lengths of time of the low levels output by the optical fiber line 6 are different. If, in the next period of time, for example, the level signal output by the optical fiber line 6 corresponding to the input end ④ presents a long low-level signal, and the level signal output by the optical fiber line 6 corresponding to the input end ⑤ changes from a high-level signal to a short low-level signal and receives the next high-level signal first, it is a clockwise rotation; otherwise, it is a counterclockwise rotation.

[0059] The above is the preferred implementation manner of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present invention.

Claims

1. A nuclear magnetic compatible rotary encoder, characterized in that: It includes a fixing seat, a sensing cylinder, a laser generator, a sensing module, a transmission shaft and a fiber optic connector; The fixed seat is provided with a rotating cavity, and two groups of symmetrically arranged output through holes and input through holes are provided around the axis of the rotating cavity, and the output through holes and the input through holes are connected to the rotating cavity; A cross groove is provided at one end of the sensing cylinder, and the cross groove includes a first channel and a second channel which are cross-arranged and communicate with each other with their centers overlapping; The induction cylinder is rotatably installed in the rotating cavity, and the cross slot extends into the range surrounded by the output through hole and the input through hole; The first channel and the second channel are respectively used to optically connect two groups of symmetrically arranged output through holes and input through holes; The laser generator is optically connected to the output through hole, and the sensing module is optically connected to the input through hole; The order in which the first channel and the second channel are connected to the two groups of the output through holes and the input through holes is used to determine the rotation direction of the sensing cylinder; The periodic change of the connection between the first channel or the second channel and the two groups of the output through holes and the input through holes is used to measure the rotation speed of the induction cylinder; The transmission shaft is in transmission connection with the other end of the induction cylinder; A plastic bearing is also installed in the rotating cavity; The shape of the rotating chamber is a stepped cylinder; The rotating chamber is sequentially installed with the induction cylinder and the plastic bearing from the inside to the outside; The outer ring of the plastic bearing is connected and fixed to the rotating chamber, and the induction cylinder is connected and fixed to the inner ring of the plastic bearing; The sensing module is a photoresistor module, and the photoresistor module is optically connected to the optical fiber connector.

2. The rotary encoder according to claim 1, characterized in that: The intersection angle between the lengthwise symmetric center lines of the first channel and the second channel is 27°-45°.

3. The rotary encoder according to claim 1, characterized in that: A retaining wall is provided between the first channel and the second channel on the outer ring of the sensing cylinder.

4. The rotary encoder according to claim 1, characterized in that: The rotary encoder also includes an optical fiber line; The optical fiber lines are inserted into the two groups of output through holes and the input through holes, and a plurality of the optical fiber lines are optically connected to the laser generator and the sensing module respectively.

5. The rotary encoder according to claim 4, characterized in that: The plurality of optical fiber lines are respectively inserted into the plurality of optical fiber connectors, and the plurality of optical fiber connectors are respectively optically connected with the corresponding laser generators and the sensing modules.

6. The rotary encoder according to claim 5, characterized in that: The rotary encoder also includes a housing; The housing is provided with a plurality of wire holes; The optical fiber connector, the laser generator and the induction module are all installed in the housing, and the optical fiber line passes through the line hole.

7. The rotary encoder according to claim 4, characterized in that: The materials used to make the fixing seat, the sensing cylinder, the optical fiber line and the transmission shaft are all polylactic acid.

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