CN115035752A

CN115035752A - Education and teaching device based on artificial intelligence and use method thereof

Info

Publication number: CN115035752A
Application number: CN202210741679.4A
Authority: CN
Inventors: 张伟国; 王慧
Original assignee: Yantai Nanshan University
Current assignee: Yantai Nanshan University
Priority date: 2022-06-28
Filing date: 2022-06-28
Publication date: 2022-09-09

Abstract

The invention discloses an educational teaching device based on artificial intelligence and a use method thereof, wherein the educational teaching device comprises a frame body, the frame body comprises a projection screen and a writing board, and the upper end of the frame body is connected with a camera; the writing board is fixedly connected with a fixed plate, the fixed plate is arranged in the groove in a sliding mode, a movable hook is connected in the groove in a rotating mode, a sliding groove is formed in the fixed plate, and the movable hook is arranged in the sliding groove in a sliding mode; the frame body is connected with a proximity switch, and the writing board is connected with an induction metal sheet matched with the proximity switch; the desk is internally provided with a student screen which is arranged in the vertical direction in a sliding connection mode, the student screen further comprises a voice recognition mechanism, the student screen is connected with a lifting mechanism, and the upper surface of the student screen is lower than or equal to the upper surface of the desk in the initial state. The invention has convenient operation, can effectively enhance the teaching interaction between students and teachers, is beneficial to the teachers to adjust the teaching progress and teaching methods in time, and improves the teaching quality.

Description

Education and teaching device based on artificial intelligence and use method thereof

Technical Field

The invention relates to the technical field of intelligent education, in particular to an education teaching device based on artificial intelligence and a using method thereof.

Background

Artificial intelligence, abbreviated in english as AI. The method is a new technical science for researching and developing theories, methods, technologies and application systems for simulating, extending and expanding human intelligence. Artificial intelligence is a branch of computer science that attempts to understand the essence of intelligence and produce a new intelligent machine that can react in a manner similar to human intelligence. After artificial intelligence and education are combined, an answering thought and a correction method can be provided; the classroom teaching behavior recognition and interaction capacity is improved; and judging whether the students are willing to accept the learning content. The application of artificial intelligence in the field of education is as follows: personalized learning, education and teaching interaction, virtual instructor, educational robot and scene type education.

The present education and teaching device based on artificial intelligence relies on multimedia such as projecting apparatus mostly to teach among the device, and is not intimate with student's interaction, and the mr is difficult to in time master student's learning level, and the mr is writing the in-process, because of the student position is different, the back row student appears the problem that the mr writes the content clearly very easily, consequently needs an urgent need for an education and teaching device based on artificial intelligence's reinforcing is interactive, timely feedback.

Disclosure of Invention

In order to solve the problems in the prior art, an educational and teaching device based on artificial intelligence and a using method thereof are provided.

The technical scheme adopted by the invention for solving the technical problems is as follows:

the invention provides an educational and teaching device based on artificial intelligence, which comprises,

the writing board is connected with the frame body through a first spring, the upper end of the frame body is connected with a camera, and the camera is arranged above the writing board;

the writing board is fixedly connected with a fixed plate, the fixed plate is arranged in the groove in a sliding mode, a movable hook is connected in the groove in a rotating mode, the fixed plate is provided with a sliding groove, and the other end of the movable hook is arranged in the sliding groove in a sliding mode;

the writing board is connected with an induction metal sheet matched with the proximity switch, and a gap is reserved between the induction metal sheet and the proximity switch in an initial state so that the proximity switch does not work;

the desk comprises a plurality of desks, student screens arranged in the vertical direction are connected in the desks in a sliding mode, the student screens are connected with a lifting mechanism, and in an initial state, the upper surfaces of the student screens are lower than or equal to the upper surfaces of the desks;

and the proximity switch, the camera, the student screen and the driving mechanism are connected with the computer.

Preferably, the fixing plate is provided with a first sliding chute, the frame body is fixedly connected with a guide post, and the guide post is slidably arranged in the first sliding chute; the guide post sleeve is provided with a second spring, one end of the second spring is connected with the frame body, and the other end of the second spring is connected with the fixing plate.

Preferably, the frame body is provided with a second sliding groove, the T-shaped column is fixedly connected with the writing board, and the T-shaped column and the first spring are slidably arranged in the second sliding groove; first spring one end with the support body links to each other, the first spring other end with T type post links to each other.

Preferably, the sliding groove comprises a left bending part, a right bending part and a sharp corner part in sequence from left to right, and the sharp corner part and the right bending part are arranged in a staggered mode.

Preferably, when the movable hook is located in the left bending part, the first spring and the second spring are both in a compressed state, and the T-shaped column is in contact with the second sliding groove.

Preferably, in an initial state, the camera is positioned right above the writing board; when the movable hook is positioned in the right bending part, the writing board moves to one side of the camera; the student screen is a touch screen and further comprises a voice recognition mechanism.

Preferably, the lifting mechanism comprises a lifting motor, the desk is fixedly connected with a fixed box, and the student screen and the lifting motor are arranged in the fixed box; student screen fixedly connected with screw rod, fixed case rotates and is connected with the nut, the nut with screw rod threaded connection, elevator motor is used for the drive the nut rotates.

Preferably, the nut fixing sleeve is provided with a first gear, the lifting motor is connected with a second gear, and the first gear is meshed with the second gear; the fixed box is fixedly connected with a plurality of guide sleeves, the student screen is fixedly connected with limiting columns, and the limiting columns are arranged in the guide sleeves in a sliding mode.

The invention also provides a use method of the artificial intelligence-based education teaching device, and the artificial intelligence-based education teaching device comprises the following steps:

s1: the teacher projects courseware on the projection screen, and when needing to write, the teacher presses down the writing board, and the writing board drives the fixing plate and the T-shaped column to move;

s2: along with the movement of the writing board, the movable hook moves in the sliding groove and moves from the left bent part to the right bent part, the T-shaped column slides in the second sliding groove at the moment, the first spring and the second spring are both in a compressed state, the induction metal sheet moves to one side of the proximity switch at the moment, and the proximity switch transmits a corresponding signal to the computer;

s3: the computer controls the lifting mechanism, the lifting mechanism drives the student screen to move upwards so as to move above the desk, meanwhile, the computer controls the camera to work, the content on the writing board is put on the student screen, at the moment, the student can see the content on the writing board through the student screen, and the student can interact with a teacher through the student screen;

s4: after the teaching was accomplished, press the board, the activity hook slides in the sliding tray under the effect of closed angle portion to slide left kink, response sheetmetal this moment to the direction motion of keeping away from proximity switch, and proximity switch transmits corresponding signal and gives the computer, and computer control elevating system, camera and student screen stop work.

Preferably, the working method of the lifting mechanism comprises the following steps: lifting motor passes through the second gear and drives first gear revolve, and first gear drives the nut and rotates, and the nut passes through the screw rod and drives the vertical direction motion of student's screen, and at this moment, spacing post slides in the uide bushing.

Compared with the prior art, the invention has the beneficial effects that:

1. the movable writing board is arranged in the teaching desk, when the writing board moves, the induction metal sheet is matched with the proximity switch, the proximity switch works at the moment, the camera, the lifting mechanism and the student screen can be controlled to work, the student screen is driven to lift by the lifting mechanism, the camera can convey the content written on the writing board by a teacher to the student screen at the moment, the student can observe the content written by the teacher through the student screen and interact with the student screen, the teaching interaction between the student and the teacher can be effectively enhanced, the teaching progress and teaching method can be timely adjusted by the teacher, and the teaching quality is improved.

2. The movable hook is arranged in the pen holder, the movable hook can slide in the sliding groove after the writing board is pressed down, when the movable hook moves to the right bent portion, the induction metal sheet moves to one side of the proximity switch at the moment, the proximity switch works, after the teaching work is finished, the writing board is continuously pressed downwards with force, the movable hook can continuously slide in the sliding groove, and therefore the movable hook slides to the left bent portion, the proximity switch stops working, the operation is convenient, the relative fixing work of the position of the writing board can be achieved only by pressing the writing board, and the interaction effect between teachers and students is effectively enhanced.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

FIG. 1 is a front view of a tablet portion of the present invention;

FIG. 2 is a schematic view of the structure of part A-A in FIG. 1;

FIG. 3 is a schematic view of the fixing plate of FIG. 2;

FIG. 4 is a side view of a portion of the desk of the present invention;

FIG. 5 is a schematic view of the structure of part B-B in FIG. 4;

fig. 6 is an overall flow chart of the present invention.

Description of reference numerals:

1, a frame body; 2 a projection screen; 3 a projector; 4, a writing board; 5, a camera; 6 a first spring; 7 a guide post; 8 a second spring; 9 a first module; 10, a movable hook; 11 a proximity switch; 12 fixing the plate; a 13T-shaped column; 14, a desk; 15 fixing the box; 16 a second module; 17 a student screen; 18 a first gear; 19 a screw rod; 20, a nut; 21 a second gear; 22 a lift motor; 23 limiting columns; 24, a guide sleeve; 25 induction metal sheet; 26 sharp corners; 27 right bend; 28 left bent part.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention and are not to be construed as limiting the present invention.

Referring to fig. 1-6, this embodiment provides an educational and teaching device based on artificial intelligence, which includes a frame 1, the frame 1 includes a projection screen 2 and a writing board 4, one side of the projection screen 2 is provided with a projector 3, the projector 3 can put corresponding projection information on the projection screen 2, so as to facilitate the display of teaching materials such as courseware. The writing board 4 is disposed at one side of the projection screen 2, and a teacher can perform corresponding writing work through the writing board 4.

Tablet 4 passes through

T type post

13 and 1 sliding connection of support body, and tablet 4 links to each other with support body 1 through

first spring

6, and 1 upper end of support body is connected with camera 5, and camera 5 sets up in tablet 4 top, and under the initial condition, camera 5 is out of work.

The frame body 1 is provided with a second sliding chute, the T-shaped column 13 is fixedly connected with the writing board 4, and the T-shaped column 13 and the first spring 6 are arranged in the second sliding chute in a sliding manner; one end of the first spring 6 is connected with the frame body 1, and the other end of the first spring 6 is connected with the T-shaped column 13.

The first spring 6 is used for the reset work of the T-shaped column 13, and the first spring 6 is always in a compressed state. The number of the T-shaped posts 13 can be several according to actual needs, in this example, four T-shaped posts 13 are provided, and are respectively disposed at four opposite corners of the tablet 4.

The second spout includes narrow slot and wide groove, and narrow slot and wide groove are linked together, and the left end of T type post 13 slides in the wide groove all the time, and the left end width of T type post 13 is greater than the width of narrow groove to prevent under the effect of first spring 6, T type post 13 shifts out the second spout.

The rack body 1 is provided with a groove, the writing board 4 is fixedly connected with a fixed plate 12, the fixed plate 12 is arranged in the groove in a sliding manner, a movable hook 10 is rotationally connected in the groove, the fixed plate 12 is provided with a sliding groove, and the other end of the movable hook 10 is arranged in the sliding groove in a sliding manner; the fixing plate 12 always slides in the groove.

The frame body 1 is further connected with a proximity switch 11, the writing board 4 is connected with an induction metal sheet 25 matched with the proximity switch 11, and in an initial state, a gap is reserved between the induction metal sheet 25 and the proximity switch 11 so that the proximity switch 11 does not work. When the tablet 4 moves to the left, the tablet 4 can drive the sensing metal plate 25 to move to one side of the proximity switch 11, so that the proximity switch 11 is operated.

The desk comprises a plurality of desks 14, wherein a student screen 17 arranged in the vertical direction is connected in the desks 14 in a sliding mode, the student screen 17 is connected with a lifting mechanism, and in an initial state, the upper surface of the student screen 17 is lower than or equal to the upper surface of the desks 14;

the computer, the proximity switch 11, the camera 5, the student screen 17 and the driving mechanism are all connected with the computer.

The fixing plate 12 is provided with a first sliding chute, the frame body 1 is fixedly connected with a guide post 7, and the guide post 7 is arranged in the first sliding chute in a sliding manner; the guide post 7 cover is equipped with second spring 8, and second spring 8 one end links to each other with support body 1, and the second spring 8 other end links to each other with fixed plate 12.

The fixing plate 12 slides along the length direction of the guide post 7 all the time, and the guide post 7 plays a guiding role for the movement of the fixing plate 12. The second spring 8 is used for the return operation of the fixed plate 12, and the second spring 8 is always in a compressed state.

The sliding groove comprises a left bending part 28, a right bending part 27 and a sharp corner part 26 from left to right in sequence, and the sharp corner part 26 and the right bending part 27 are arranged in a staggered mode.

When the movable hook 10 is located in the left bent portion 28, the first spring 6 and the second spring 8 are both in a compressed state, and the T-shaped pillar 13 is in contact with the second sliding groove. The movable hook 10 may move in the sliding groove as the tablet 4 is pressed.

Since the first spring 6 and the second spring 8 are always in a compressed state, the movable hook 10 can be brought into close contact with the left bent portion 28 or the right bent portion 27 by the action of the springs.

In an initial state, the camera 5 is positioned right above the writing board 4; when activity hook 10 was located right kink 27 in, tablet 4 removed camera 5 one side, camera 5 can record in real time the content of tablet 4 this moment, thereby make student screen 17 show the content of tablet 4 in real time, wherein only when pressing tablet 4, response sheetmetal 25 and proximity switch 11 mutually support, proximity switch 11 transmits corresponding signal, just can work this moment camera 5, just can drive student screen 17 through elevating system this moment and rise.

The elastic force of the first spring 6 and the second spring 8 is suitable enough to prevent the movement of the tablet 4 caused by the teacher pressing the tablet 4 carelessly while writing, and the first spring 6 and the second spring 8 with suitable elastic force can be selected through corresponding tests because excessive force is not required during writing.

The student screen 17 also comprises a voice recognition mechanism, and through the voice recognition structure, the voice of a student can be recognized, when a teacher asks questions, the student can answer the questions through the voice recognition mechanism, and when the student asks questions, the student can ask the teacher questions through the voice recognition mechanism.

Student screen 17 is the touch-sensitive screen, and student's accessible touch student screen 17 carries out corresponding operation of asking for answering, and for example the mr is when the lecture, and the accessible computer sends certain title to student screen 17, and student's accessible touch student screen 17 carries out corresponding answer work, and student's answer condition is looked over in real time to mr's accessible computer, can effectively strengthen the teaching interdynamic between student and the mr, helps the mr in time to adjust the teaching progress and give lessons the method, has improved teaching quality.

The lifting mechanism comprises a lifting motor 22, the desk 14 is fixedly connected with a fixed box 15, and the student screen 17 and the lifting motor 22 are arranged in the fixed box 15; student's screen 17 fixedly connected with screw rod 19, fixed case 15 rotates and is connected with nut 20, and nut 20 and screw rod 19 threaded connection, elevator motor 22 are used for driving nut 20 to rotate. The nut 20 is rotatably connected to the stationary box 15 by means of a bearing, and when the nut 20 is rotated, it drives the screw 19 to move vertically.

The nut 20 is fixedly sleeved with a first gear 18, the lifting motor 22 is connected with a second gear 21, and the first gear 18 is meshed with the second gear 21; the fixed box 15 is fixedly connected with a plurality of guide sleeves 24, the student screen 17 is fixedly connected with a limiting post 23, and the limiting post 23 is arranged in the guide sleeves 24 in a sliding mode.

The limiting column 23 always slides in the guide sleeve 24, the student screen 17 can be prevented from rotating under the action of the limiting column 23, the cross sections of the limiting column 23 and the guide sleeve 24 are rectangular, and the distance between the student screen 17 and students is enough proper so as not to influence the normal use of the students on the desk 14.

Support body 1 is the first module of fixed connection 9 still, and proximity switch 11 links to each other through first module 9 and computer, and fixedly connected with second module 16 in the fixed box 15, elevator motor 22 links to each other through second module 16 and computer. Bluetooth modules are arranged in the first module 9 and the second module 16, wireless communication can be achieved through the Bluetooth modules, and information interaction between the proximity switch 11, the lifting motor 22 and a computer is facilitated.

s1: the teacher projects courseware on the projection screen 2, when needing to write, the teacher presses the writing board 4, and the writing board 4 drives the fixing plate 12 and the T-shaped column 13 to move;

s2: along with the movement of the tablet 4, the movable hook 10 moves in the sliding groove, moves from the left bent part 28 to the right bent part 27, at this time, the T-shaped column 13 slides in the second sliding groove, the first spring 6 and the second spring 8 are both in a compressed state, at this time, the sensing metal sheet 25 moves to one side of the proximity switch 11, and the proximity switch 11 transmits a corresponding signal to the computer;

s3: the computer controls the lifting mechanism, the lifting mechanism drives the student screen 17 to move upwards so as to move above the desk 14, meanwhile, the computer controls the camera 5 to work, the content on the writing board 4 is put on the student screen 17, at the moment, the student can see the content on the writing board 4 through the student screen 17, and the student can interact with a teacher through the student screen 17;

s4: after the teaching is completed, the writing board 4 is pressed down, the movable hook 10 slides in the sliding groove under the action of the sharp corner 26, so that the movable hook slides to the left bent part 28, the induction metal sheet 25 moves towards the direction far away from the proximity switch 11 at the moment, the proximity switch 11 transmits a corresponding signal to the computer, and the computer controls the lifting mechanism, the camera 5 and the student screen 17 to stop working.

The working method of the lifting mechanism comprises the following steps: the lifting motor 22 drives the first gear 18 to rotate through the second gear 21, the first gear 18 drives the nut 20 to rotate, the nut 20 drives the student screen 17 to move in the vertical direction through the screw rod 20, and at the moment, the limiting column 23 slides in the guide sleeve 24.

It should be noted that, when board 4 removes, response sheetmetal 25 and proximity switch 11 cooperate, proximity switch 11 work this moment, steerable camera 5, elevating system and student screen 17 work, elevating system drives student screen 17 and rises, camera 5 can carry student screen 17 with the content that mr wrote on board 4 this moment on, student screen 17 is observed to student accessible student screen 17 content that mr wrote, and interact through student screen 17, can effectively strengthen the teaching interdynamic between student and the mr, help mr in time to adjust the teaching progress and the method of giving lessons, the teaching quality has been improved.

In addition, after teacher pressed down tablet 4, movable hook 10 can slide in the sliding tray, when movable hook 10 moved right kink 27, response sheetmetal 25 moved proximity switch 11 one side this moment, proximity switch 11 work, after teaching work, continue to press down tablet 4 hard downwards, movable hook 10 can continue to slide in the sliding tray, thereby slide left kink 28, make proximity switch 11 stop work, and convenient for operation, only need press down tablet 4, can realize the relatively fixed work of tablet 4 positions, the interactive effect between teachers and students has effectively been strengthened.

While embodiments of the invention have been shown and described, it will be understood by those of ordinary skill in the art that: various changes, modifications, substitutions and alterations can be made to the embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. An artificial intelligence-based education and teaching device is characterized by comprising,

the rack body (1) comprises a projection screen (2) and a writing board (4), the writing board (4) is connected with the rack body (1) in a sliding mode through a T-shaped column (13), the writing board (4) is connected with the rack body (1) through a first spring (6), a camera (5) is connected to the upper end of the rack body (1), and the camera (5) is arranged above the writing board (4);

the writing board is characterized in that the frame body (1) is provided with a groove, the writing board (4) is fixedly connected with a fixed plate (12), the fixed plate (12) is arranged in the groove in a sliding mode, a movable hook (10) is connected in the groove in a rotating mode, the fixed plate (12) is provided with a sliding groove, and the other end of the movable hook (10) is arranged in the sliding groove in a sliding mode;

the rack body (1) is further connected with a proximity switch (11), the writing board (4) is connected with an induction metal sheet (25) matched with the proximity switch (11), and in an initial state, a gap is reserved between the induction metal sheet (25) and the proximity switch (11) so that the proximity switch (11) does not work;

the desk comprises a plurality of desks (14), wherein student screens (17) arranged in the vertical direction are connected in the desks (14) in a sliding mode, the student screens (17) are connected with a lifting mechanism, and in an initial state, the upper surfaces of the student screens (17) are lower than or equal to the upper surfaces of the desks (14);

and the proximity switch (11), the camera (5), the student screen (17) and the driving mechanism are all connected with the computer.

2. The artificial intelligence-based education and teaching device according to claim 1, wherein the fixing plate (12) is provided with a first sliding groove, the frame body (1) is fixedly connected with a guide post (7), and the guide post (7) is slidably arranged in the first sliding groove; guide post (7) cover is equipped with second spring (8), second spring (8) one end with support body (1) links to each other, second spring (8) other end with fixed plate (12) link to each other.

3. The artificial intelligence-based education and teaching device according to claim 2, wherein the frame body (1) is provided with a second sliding groove, the T-shaped column (13) is fixedly connected with the writing board (4), and the T-shaped column (13) and the first spring (6) are slidably arranged in the second sliding groove; one end of the first spring (6) is connected with the frame body (1), and the other end of the first spring (6) is connected with the T-shaped column (13).

4. The artificial intelligence based education and teaching device according to claim 3, wherein the sliding groove comprises a left bending part (28), a right bending part (27) and a sharp corner part (26) from left to right in sequence, and the sharp corner part (26) and the right bending part (27) are arranged in a staggered manner.

5. An artificial intelligence based educational and educational device according to claim 4, wherein when the movable hook (10) is located within the left bent portion (28), the first spring (6) and the second spring (8) are both in a compressed state, when the T-shaped post (13) and the second runner are in contact.

6. An artificial intelligence based educational and teaching apparatus according to claim 5, wherein in the initial state, the camera (5) is positioned right above the tablet (4); when the movable hook (10) is positioned in the right bending part (27), the writing board (4) moves to one side of the camera (5); the student screen (17) is a touch screen, and the student screen (17) further comprises a voice recognition mechanism.

7. An artificial intelligence based educational and educational apparatus according to claim 1, wherein the elevating mechanism comprises an elevating motor (22), a fixed box (15) is fixedly connected to the desk (14), the student screen (17) and the elevating motor (22) are disposed in the fixed box (15); student screen (17) fixedly connected with screw rod (19), fixed case (15) are rotated and are connected with nut (20), nut (20) with screw rod (19) threaded connection, elevator motor (22) are used for the drive nut (20) rotate.

8. An artificial intelligence based education and teaching device according to claim 7, wherein the nut (20) is fixedly sleeved with a first gear (18), the lifting motor (22) is connected with a second gear (21), and the first gear (18) is meshed with the second gear (21); fixed case (15) fixedly connected with a plurality of uide bushing (24), student screen (17) fixedly connected with spacing post (23), spacing post (23) slide to set up in uide bushing (24).

9. A method for using an artificial intelligence-based educational teaching apparatus, wherein an artificial intelligence-based educational teaching apparatus according to any one of claims 6 to 8 is used, comprising the steps of:

s1: a teacher projects courseware on the projection screen (2), when needing to write, the writing board (4) is pressed down, and the writing board (4) drives the fixing plate (12) and the T-shaped column (13) to move;

s2: along with the movement of the writing board (4), the movable hook (10) moves in the sliding groove and moves from the left bent part (28) to the right bent part (27), at the moment, the T-shaped column (13) slides in the second sliding groove, the first spring (6) and the second spring (8) are both in a compressed state, at the moment, the induction metal sheet (25) moves to one side of the proximity switch (11), and the proximity switch (11) transmits a corresponding signal to a computer;

s3: the computer controls a lifting mechanism, the lifting mechanism drives a student screen (17) to move upwards so as to move above the desk (14), the computer controls a camera (5) to work at the same time, the content on the writing board (4) is put on the student screen (17), at the moment, the student can see the content on the writing board (4) through the student screen (17), and the student can interact with a teacher through the student screen (17);

s4: after the teaching is completed, the writing board (4) is pressed, the movable hook (10) slides in the sliding groove under the action of the sharp corner part (26) so as to slide to the left bent part (28), the induction metal sheet (25) moves towards the direction far away from the proximity switch (11), the proximity switch (11) transmits a corresponding signal to the computer, and the computer controls the lifting mechanism, the camera (5) and the student screen (17) to stop working.

10. The use method of an artificial intelligence based educational teaching apparatus according to claim 9, wherein the elevating mechanism working method comprises: lifting motor (22) drive first gear (18) through second gear (21) and rotate, and first gear (18) drive nut (20) and rotate, and nut (20) drive student's screen (17) vertical direction through screw rod (20) and move, and at this moment, spacing post (23) slide in uide bushing (24).