CN109532001B - A leveling method for a three-dimensional printing platform and a leveling system using the same - Google Patents

Abstract

The invention relates to a leveling method of a three-dimensional printing platform and a leveling system using the same, belonging to the technical field of rapid prototyping. The leveling method comprises the following steps: (1) print surface at three support points P based on acquisition of print platform₁、P₂And P₃Coordinate value of (c) determining a normal vector n of the printing platform_p(ii) a (2) Obtaining a normal vector n_pThe smaller of the included angles with the Z axis is greater than a preset threshold value, and the highest point or the lowest point P is used₃Establishing a local coordinate system P for the origin₃‑x₃y₃z₃Obtaining a normal vector n_pAnd x₃P₃z₃Angle α between planes and y₃P₃z₃Angle between planes

And with P₃For fixed point, adjusting another two supporting points around y₃The shaft rotates α degrees and rotates around x₃Rotation of the shaft

An angle; if the smaller one is smaller than or equal to the preset threshold value, the leveling process is ended, and the printing platform is in a horizontal state. The leveling method can well achieve the leveling effect and can be applied to the technical field of three-dimensional printing.

Description

A leveling method for a three-dimensional printing platform and a leveling system using the same

This application is a divisional application for an invention patent with an application number of CN201710461594.X and an invention title of "A leveling system for a three-dimensional printing platform and its distance measuring device and leveling method".

technical field

The invention relates to the technical field of rapid prototyping, in particular to a leveling method for leveling a printing platform of a three-dimensional printing device and a leveling system using the leveling method.

Background technique

A three-dimensional printing device is a device that builds a three-dimensional object by layer-by-layer printing using molding materials based on a digital model of a three-dimensional object.

As shown in FIG. 1 , it is a three-dimensional printing device that supplies forming materials to the print head 05 in the form of forming filaments. The reel 02 is wound with forming filaments 03, and the reel 02 is installed on the reel of the three-dimensional printing device. On the rotating shaft 01 of the mounting frame, the forming wire 03 can be supplied to the print head 05. During use, the forming wire 03 is pulled out from the reel 02, and the straightened forming wire is passed through the flexible conduit 04 made of material with low frictional resistance until the forming wire is supplied to the print head 05 by The feeding driving wheel 053 and the feeding driven wheel 054 driven by the motor 055, under the clamping and driving of the feeding driving wheel 053 and the feeding driven wheel 054, the forming wire 03 enters the electric heater 051, and the forming wire is in the electric heater 051. After heating The molding material in a molten state is extruded from the printing nozzle 052 provided at the end of the electric heater 051 and deposited on the printing platform 06 under the push of the subsequent molding wire; the controller of the three-dimensional printing device controls the printing head 05 in a horizontal It moves in the X-Y plane, and at the same time controls the printing platform 06 to move in the vertical Z direction, so as to print out predetermined three-dimensional objects layer by layer.

In the process of printing three-dimensional objects, the printing quality of the first slice layer is very important, not only to ensure that the distance between the print head and the printing platform 06 during initial printing is less than the layer thickness of the slice layer, usually 0.1 mm to 0.2 mm, but also It should be ensured that the normal direction of the printing surface of the printing platform 06 is arranged along the Z axis of the coordinate system of the printing head 05 .

Therefore, before starting printing, it is necessary to manually level the spatial position of the printing platform 06 relative to the print head 05. Usually, a level is used to measure the horizontal state of the printing platform 06, and by adjusting the adjustment mechanism provided below the printing platform 06 In order to achieve leveling, not only the adjustment process is complicated, but also the manufacturing error and placement relationship lead to a big difference between the X-Y plane and the horizontal plane of the coordinate system formed by the movement of the print head, and it is difficult to obtain the desired leveling effect.

SUMMARY OF THE INVENTION

The main purpose of the present invention is to provide a method for leveling a three-dimensional printing platform, so as to adjust the normal direction of the printing platform to be arranged along the Z-axis direction in the coordinate system of the print head;

Another object of the present invention is to provide a leveling system for a three-dimensional printing platform using the above-mentioned leveling method, so as to improve the leveling precision and the degree of automation.

并以P₃为定点，调整点P₁、P₂绕y₃轴旋转α角度及绕x₃轴旋转

角度。In order to achieve the above purpose, the three-dimensional printing platform leveling method provided by the present invention includes an acquisition step and an adjustment step; the acquisition step includes acquiring the coordinate values P ₁ =(x ₁ , y ₁ , z ₁ ), P ₂ =(x ₂ , y ₂ , z ₂ ), P ₃ =(x ₃ , y ₃ , z ₃ ), and the normal vector n _p of the printing platform is determined based on the obtained coordinate values, and the support point is The three lifting mechanisms supported below the printing platform support the hinge points of the printing platform; the adjustment step includes establishing a local coordinate system P ₃ -x ₃ y ₃ z ₃ with the highest point or the lowest point P ₃ as the origin, and obtaining a normal vector The angle α between n _p and the x ₃ P ₃ z ₃ plane and the angle between it and the y ₃ P ₃ z ₃ plane

And take P ₃ as a fixed point, adjust the points P ₁ and P ₂ to rotate α around the y ₃ axis and rotate around the x ₃ axis

angle.

Through the angle adjustment method, the normal direction of the printing surface of the printing platform can be better adjusted to match the Z axis in the printing head coordinate system, so as to achieve a better leveling effect.

The specific solution is that before the adjustment step and after the obtaining step, it further includes a judgment step: obtaining the smaller of the angle between the normal vector n _p and the Z axis, and if the smaller one is greater than the preset threshold, the adjustment step is performed. ; Otherwise, the leveling process is ended, and the printing platform is in a horizontal state. The pre-determination step is used to avoid unnecessary adjustment steps for the printing platform that is already in a leveled state.

角度的步骤包括：The preferred solution is to take P ₃ as the fixed point, and adjust the points P ₁ and P ₂ to rotate around the y ₃ axis by an angle of α and rotate around the x ₃ axis

The angle steps include:

( ₁ ) The adjustment amount of the lifting mechanism at the control point P1 is

And the adjustment amount of the lifting mechanism at the control point _P2 is

to obtain the adjusted points P′ ₁ and P′ ₂ ;

( ₂ ) The adjustment amount of the lifting mechanism at the adjustment point P'1 is:

And the adjustment amount of the lifting mechanism at the adjustment point P' ₂ is

to obtain the leveled printing platform;

in,

Another preferred solution is that, in the obtaining step, the coordinate values of P1, P2 and P3 are obtained based on the distance measuring device, the distance measuring device includes a steering gear, a cam mechanism and a contact trigger unit; the cam of the cam mechanism and the output of the steering gear The shaft is connected by transmission, and the end of the follower in its movable direction is fixedly connected with the contact trigger unit; the contact trigger unit outputs a contact trigger signal to the controller of the steering gear as a trigger signal for controlling the rotation of the motor of the steering gear. The return signal is obtained through the trigger unit, that is, contact measurement, which can effectively improve the ranging accuracy; at the same time, the angle displacement of the cam is obtained through the angle sensor of the steering gear, and the follower is closely attached to the cam under the action of the spring restoring force, which can effectively improve the accuracy of distance measurement. The occurrence and accumulation of backhaul errors in the prior art are effectively avoided.

A more preferred solution is that the contact trigger unit is a travel switch.

A further solution is to use the above-mentioned distance measuring device to measure, and the step of obtaining the coordinate values of the printing surface of the printing platform at the three supporting points includes: controlling the printing head to move to the points P ₁ , P ₂ , and P ₃ in the XY plane. Right above, obtain the x and y values in the coordinate value of the measurement point, drive the steering gear to rotate to drive the travel switch to move down until it is triggered, and obtain the z value in the coordinate value of the measurement point.

Another more preferred solution is that two electromagnets are installed on the frame of the distance measuring device as external connection fixed ports, and the distance between the two electromagnets in the movable direction is adjustable. It is convenient to detachably install the distance measuring device on the print head of the three-dimensional printing device, and at the same time better match the three-dimensional printing devices of different models.

In order to achieve the above-mentioned other object, the three-dimensional printing platform leveling system provided by the present invention uses the leveling method described in any of the above technical solutions, and includes a three-dimensional printing device and a distance measuring device, and the three-dimensional printing device includes a control unit and a stage. ; The stage includes a printing platform and an adjustment unit controlled by the control unit, the adjustment unit includes three lifting mechanisms supported under the printing platform, and the three supporting points are not collinear; the distance measuring device is detachably installed on the print head On the upper part, it includes a steering gear, a contact trigger unit and a displacement conversion mechanism for converting the rotation of the steering gear into a reciprocating movement of the contact trigger unit along the Z axis, and the trigger position of the contact trigger unit is lower than the lower port of the print nozzle of the print head; The control unit outputs a control signal to the steering gear, and the steering gear outputs the detection signal of its angle sensor to the control unit; the contact trigger unit outputs a trigger signal to the controller of the steering gear, which is used as a trigger control signal for controlling the reverse return of the motor of the steering gear.

During the working process, the coordinate values of the printing surface of the printing platform at the three supporting points are measured by the distance measuring device detachably installed on the printing head, so as to facilitate the subsequent adjustment of the position of the printing platform by controlling the lifting mechanism, so as to achieve the adjustment of the printing platform. After the leveling is completed, the distance measuring device can be disassembled from the print head to prevent the fixed position of the distance measuring device from changing with the vibration of the print head during the printing process, which will affect the subsequent leveling accuracy, and It can avoid interference with the printed 3D object during the printing process. In addition, the position detection in the Z-axis direction is realized by driving the contact trigger unit by the steering gear, which can effectively improve the ranging accuracy.

The specific scheme is that the displacement conversion mechanism is a cam mechanism, the cam of the cam mechanism is drivingly connected with the output shaft of the steering gear, and the lower end of the follower is fixedly connected with the contact trigger unit. The angle displacement of the cam is obtained by the steering gear angle sensor, and the follower is in close contact with the cam under the action of the spring restoring force. The combination of the two can effectively avoid the occurrence and accumulation of return errors in the prior art.

A preferred solution is that the distance measuring device is detachably and fixedly connected to the print head through an electromagnet fixed on its frame. It is convenient for the fixed connection and removal of the distance measuring device and the print head.

Description of drawings

1 is a schematic structural diagram of an existing three-dimensional printing device;

2 is a perspective view of a distance measuring device in an embodiment of the present invention;

FIG. 3 is an exploded view of the structure of a ranging device in an embodiment of the present invention;

4 is a perspective view of a stage in an embodiment of the present invention;

Fig. 5 is the process schematic diagram of the judging step in the embodiment of the present invention;

FIG. 6 is a schematic process diagram of a leveling step in an embodiment of the present invention.

Detailed ways

The present invention will be further described below with reference to the embodiments and the accompanying drawings.

Example

Referring to FIGS. 2 to 4 , the automatic leveling system of the 3D printing platform includes a 3D printing device and a distance measuring device 10 , the 3D printing device includes a control unit, a printing head and a stage 11 , and the stage 11 includes a printing platform 12 and an adjustment unit controlled by the control unit.

2 and 3 , the distance measuring device 10 includes a frame 2 , a mounting plate 3 , a steering gear 4 , a cam mechanism 5 , a travel switch 6 and two electromagnets 7 .

The frame 2 is a profile structure, and the mounting plate 70 of the electromagnet 7 is fixed on the frame 2 by fixing bolts 71. The fixing bolts 71 can slide along the I-shaped slot 20, so that the distance between the two electromagnets 7 can be adjusted. . And the entire distance measuring device 10 is detachably mounted on the print head through two electromagnets 7 .

The mounting plate 3 is fixed on the frame 2 by two fixing bolts 30 , and the position of the mounting plate 3 can be adjusted by adjusting the positions of the fixing bolts 30 in the I-shaped groove 21 .

The steering gear 4 is fixed on the mounting plate 3 by fixing bolts 40, which includes a casing 41, a motor, an angle sensor, a controller, a small-diameter gear 42 and a steering wheel 43, and the steering wheel 43 and the small-diameter gear 42 are drivingly connected, so as to pass the small-diameter gear Receiving the rotational displacement generated by the motor, the steering wheel 42 constitutes the output shaft of the steering gear 4 in this embodiment. In this embodiment, the parameters of the steering gear 4 used are: dead zone of 4 μs, maximum pulse width of 500-2500 μs, maximum angle of 295°, voltage range of 4.8V-6.6V, and speed of 0.25s/s at 4.8V 60°, 0.21s/60° at 6.6V, torque is 19.9kg·cm at 4.8V, 25.3kg·cm at 6.6V, and the number of output teeth is 25.

The cam mechanism 5 constitutes a displacement conversion mechanism that converts the rotational displacement output by the steering gear 4 into the vertical displacement of the travel switch 6 , and includes a cam 51 , a follower 52 , a return spring 53 and a frame 54 .

The cam 51 is fixed on the steering wheel 42 of the steering gear 4 by fixing screws 510 .

The follower 52 includes a receiving plate 521 and a T-shaped transmission plate 522. The T-shaped transmission plate 522 includes a vertical plate part 523 and a transverse plate part 524. The vertical plate part 523 is provided with a The vertical guide grooves 525 and the transverse plate part 524 are provided with transverse mounting grooves 526 arranged along the length direction thereof.

The rack 54 includes a mounting seat 540 and a guide seat 541 . The mounting seat 540 is fixed on the rack 2 by fixing bolts 543 , and its vertical position along the profile structure of the rack 2 is adjustable. The guide base 541 is a T-shaped circular truncated structure, and is provided with guide holes arranged vertically and matched with the vertical plate part 523 .

The upper end of the vertical plate part 523 of the T-shaped transmission plate 522 passes through the guide hole on the guide seat 541 and then is inserted into the mounting hole on the lower end of the receiving plate 521 and is fixedly connected with it. The spring 53 is sleeved on the vertical The plate part 523 is outside and pressed between the guide seat 541 and the receiving plate 521 , that is, the elastic restoring force forces the receiving plate 521 away from the guide seat 541 . Of course, the upper end of the guide groove 525 can be set as an open end, and a guide rod matched with the guide groove 525 can be set in the inner hole of the mounting 540 or the guide hole of the guide seat 541 .

The travel switch 6 is fixed on the lateral plate part 524 by screws, and the mounting position of the travel switch 6 in the lateral direction is adjusted by adjusting the position of the screw in the lateral mounting 526 .

Referring to FIG. 4 , the adjusting unit includes three lifting mechanisms 13 on the printing platform 12, one is located at the middle position of one edge portion, and the other two are located at the middle position relative to the other edge portion, and the three supporting points constitute P _1. P ₂ and P ₃ form an isosceles triangle, that is, the three are not collinear. The lifting mechanism 13 includes an adjusting nut 14, an adjusting screw 15, a coupling 16 and a stepping motor 17; in this embodiment, the coupling The device 16 is an Oldham coupling. The adjusting nut 14 is fixedly connected with the printing platform 12, and the stepping motor 17 drives the adjusting screw 15 to rotate through the coupling 16, and drives the adjusting nut 14 to reciprocate vertically along it, thereby driving the supporting point of the printing platform 12 to be in the vertical direction. The adjustment of the position, that is, the displacement along the Z-axis.

Among them, the control unit of the three-dimensional printing device outputs a control signal to the controller of the steering gear 4, and the controller of the steering gear 4 outputs the detection signal of the angle sensor of the steering gear 4 to the control unit, and the travel switch 6 constitutes the Contact the trigger unit, which outputs a trigger signal to the controller of the steering gear 4 , and the trigger signal is used as a trigger control signal for the reverse return of the motor of the steering gear 4 .

The leveling method of the above-mentioned leveling system includes an acquisition step S1, a determination step S2 and an adjustment step S3.

In the acquisition step S1, referring to FIG. 4 and FIG. 5, the coordinates P ₁ =(x ₁ , y ₁ , z ₁ ) of the three vertices of the triangle P ₁ P ₂ P ₃ are measured by the distance measuring device 10 , P ₂ =(x _{2 )} , y ₂ , z ₂ ), P ₃ =(x ₃ , y ₃ , z ₃ ), that is, to obtain the coordinate values of three non-collinear measurement points P ₁ , P ₂ , P ₃ in the print head coordinate system, in In this embodiment, the points P ₁ , P ₂ , and P ₃ are the orthogonal projection positions of the support hinge points of the three lifting mechanisms 13 and the printing platform 12 on the printing plane. In addition, calibration can be set at the three points Raised structures, such as cylinders, to adjust positioning during measurement. The specific acquisition process is: control the print head to move directly above any three points P ₁ , P ₂ , and P ₃ in the xy plane to obtain the x and y axis values in the coordinate values of the three measurement points, and drive the steering gear 4 Turn to drive the travel switch 6 to move downward until it is triggered, and obtain the z-axis value of the coordinate values of the three measurement points. And when the travel switch 6 touches the printing platform, the steering gear continues to rotate until the travel switch 6 is triggered, thereby sending a trigger signal to the controller of the steering gear 4, and the controller receives the trigger signal, controls the motor to rotate and controls the slave. The member 5 is moved back to a predetermined height position, so that the measurement of the coordinate value of the lower point can be performed.

Obtaining the normal vector of the printing surface of the printing platform based on the coordinate values of the points P ₁ , P ₂ and P ₃ is:

Judging step S2, the z-axis direction vector in the print head coordinate system is n _Z = (0, 0, 1) ^T , then the angle between the two vectors can be expressed as:

That is to say, the angle between the Z axis and the normal direction of the printing plane. When the angle is smaller than the preset threshold, it means that the parallelism of the two is within the acceptable error range. If it is greater than the preset threshold, it means that the leveling process needs to be performed. , that is, the following adjustment step S3 is performed.

调平时，将平台中的点P₁、P₂先绕y₃轴旋转α角度，即图中所示的①方向，获取图中未示出调整后的法向n′_p，使得到n′_p与其在y₃P₃z₃的平面正交投影重合，再绕x₃轴旋转

角，即图中所示②方向，获取图中未示出调整后的法向n″_p，使得n″_p与z₃方向重合就可完成调平。具体过程如下：Adjusting step S3, see Fig. 6, first determine the highest or lowest point P ₃ among the three points, establish a local horizontal coordinate system P ₃ -x ₃ y ₃ z ₃ with the point P ₃ as the origin, and print the normal vector of the platform Orthogonal projection of n _p to the x ₃ P ₃ z ₃ plane and y ₃ P ₃ z ₃ plane, respectively, can obtain the angle α and α of the normal vector n _p of the platform relative to the two coordinate planes

When leveling, first rotate the points P ₁ and P ₂ in the platform by an angle α around the y ₃ axis, that is, the direction ① shown in the figure, and obtain the adjusted normal n′ _p that is not shown in the figure, so that n′ _p coincides with its orthogonal projection on the plane of y ₃ P ₃ z ₃ , and then rotates around the x ₃ axis

The angle, that is, the direction ② shown in the figure, obtains the normal direction n″ _p that is not shown in the figure after adjustment, so that n″ _p coincides with the z ₃ direction to complete the leveling. The specific process is as follows:

The orthogonal projection vector of n _p on y ₃ is:

Similarly, the orthogonal projection vector of n _p at x ₃ is:

n _px3 =n _p x ₃

The orthogonal projection vector at z ₃ is:

n _pz3 =n _p ·z ₃

Among them, x ₃ , y ₃ , and z ₃ are the unit direction vectors of the three coordinate axes, respectively.

It is known that:

In the coordinate system P ₃ -x ₃ y ₃ z ₃ , the coordinates of the three support points are:

P ₁ =(x ₁ -x ₃ , y ₁ -y ₃ , z ₁ -z ₃ ) ^T ,

P ₂ =(x ₂ -x ₃ , y ₂ -y ₃ , z ₂ -z ₃ ) ^T ,

P ₃ = (0, 0, 0) ^T

The adjustment process is:

Step 1: The process of adjusting the platform to rotate α around the y ₃ axis is: take P ₃ as the fixed point, adjust P ₂ and P ₁ to rotate α around the y ₃ axis:

_The distance between point P1 and _y3 axis is:

The screw feed adjustment at point P ₁ is:

At this point, the adjusted coordinates of P' ₁ are:

_The distance between point P2 and _y3 axis is:

Then the screw feed adjustment of P ₂ is:

At this point, the adjusted coordinates of P' ₂ are:

Step 2: The process of adjusting the platform to rotate β around the x ₃ axis is: take P ₃ as the fixed point, and adjust P′ ₂ and P′ ₁ to rotate β around the x ₃ axis:

The distance between the point P' ₁ and the _x3 axis is:

The screw feed adjustment at point P′ ₁ is:

The distance between the point P' ₂ and the x ₃ axis is:

The screw feed adjustment at point P' ₂ is:

The above-mentioned embodiments are only intended to illustrate the technical concept and characteristics of the present invention, and the purpose thereof is to enable those who are familiar with the art to understand the content of the present invention and implement them accordingly, and cannot limit the protection scope of the present invention. All equivalent changes or modifications made according to the spirit of the present invention should be included within the protection scope of the present invention.

Claims (8)

1. A leveling method of a three-dimensional printing platform is characterized by comprising the following steps:

an acquisition step of acquiring coordinate values P of the printing surface of the printing platform at three supporting points₁＝(x₁，y₁，z₁)，P₂＝(x₂，y₂，z₂)，P₃＝(x₃，y₃，z₃) And determining a normal vector n of the printing platform based on the obtained coordinate value_pThe supporting points are supporting hinge points of three lifting mechanisms supported below the printing platform to the printing platform;

adjusting step to obtain the highest point or the lowest point P₃Establishing a local coordinate system P for the origin₃-x₃y₃z₃Obtaining a normal vector n_pAnd x₃P₃z₃Angle α between planes and y₃P₃z₃Angle between planes

And with P₃To set point, adjust point P₁、P₂Around y₃The shaft rotates α degrees and rotates around x₃Rotation of the shaft

An angle;

with P₃To set point, adjust point P₁、P₂Around y₃The shaft rotates α degrees and rotates around x₃Rotation of the shaft

The angle step includes:

(1) control point P₁The adjustment amount of the lifting mechanism is

And a control point P₂The adjustment amount of the lifting mechanism is

To obtain adjusted point P'₁And P'₂；

(2) Adjusting point P'₁The adjustment amount of the lifting mechanism is

And adjusting point P'₂The adjustment amount of the lifting mechanism is

Obtaining a leveled printing platform;

wherein,

2. the leveling method according to claim 1, further comprising, before the adjusting step and after the obtaining step, a judging step of:

obtaining a normal vector n_pIf the smaller included angle between the Z axis and the Z axis is larger than a preset threshold value, the adjusting step is carried out; otherwise, the leveling process is finished, and the printing platform is in a horizontal state.

3. The leveling method according to claim 2, wherein:

in the acquiring step, coordinate values of P1, P2 and P3 are acquired based on a distance measuring device, and the distance measuring device comprises a steering engine, a cam mechanism and a contact triggering unit;

the cam of the cam mechanism is in transmission connection with an output shaft of the steering engine, and the tail end of the driven piece in the movable direction is fixedly connected with the contact triggering unit;

the contact trigger unit outputs a contact trigger signal to a controller of the steering engine to be used as a trigger signal for controlling the rotation of a motor of the steering engine;

the steering engine comprises a shell, a motor, an angle sensor, a controller, a small-diameter gear and a steering wheel; the rudder disc is in transmission connection with the small-diameter gear so as to receive the rotary displacement generated by the motor through the small-diameter gear; the steering wheel is composed of an output shaft of the steering engine.

4. Leveling method according to claim 3, characterized in that:

the contact trigger unit is a travel switch.

5. The leveling method according to claim 4, wherein the step of acquiring coordinate values of the printing surface of the printing platform at three support points comprises:

controlling the print head to move to a point P in the X-Y plane₁、P₂、P₃And (3) acquiring x and y values in the coordinate values of the measuring points, driving the steering engine to rotate so as to drive the travel switch to move downwards until the travel switch is triggered, and acquiring a z value in the coordinate values of the measuring points.

6. Leveling method according to claim 3, characterized in that:

two electromagnets serving as external fixed ports are mounted on a frame of the distance measuring device, and the distance between the two electromagnets in the movable direction is adjustable.

7. A leveling system of a three-dimensional printing platform, which uses the leveling method of claim 1 or 2, comprises a three-dimensional printing device and a distance measuring device, wherein the three-dimensional printing device comprises a control unit, a printing head and an object stage;

the object stage comprises a printing platform and an adjusting unit controlled by the control unit, the adjusting unit comprises three lifting mechanisms supported below the printing platform, and three supporting points are not collinear;

the method is characterized in that:

the distance measuring device is detachably arranged on the printing head and comprises a steering engine, a contact triggering unit and a displacement conversion mechanism for converting the rotation of the steering engine into driving the contact triggering unit to reciprocate along a Z axis, and the triggering position of the contact triggering unit is lower than the lower port of a printing nozzle of the printing head; the steering engine comprises a shell, a motor, an angle sensor, a controller, a small-diameter gear and a steering wheel; the rudder disc is in transmission connection with the small-diameter gear so as to receive the rotary displacement generated by the motor through the small-diameter gear; the rudder disc forms an output shaft of the steering engine;

the displacement conversion mechanism is a cam mechanism, a cam of the cam mechanism is in transmission connection with the output shaft, and the lower end of the driven piece is fixedly connected with the contact triggering unit;

the control unit outputs a control signal to the steering engine, and the steering engine outputs a detection signal of an angle sensor of the steering engine to the control unit; the contact trigger unit outputs a trigger signal to a controller of the steering engine to be used as a trigger control signal for controlling the reverse rotation return stroke of a motor of the steering engine.

8. The leveling system of claim 7, wherein:

the distance measuring device is detachably and fixedly connected with the printing head through an electromagnet fixedly arranged on a rack of the distance measuring device.

Images