CN112756743B - Automatic control device and control method for electric spark deposition welding contact force to displacement - Google Patents

Abstract

The invention relates to an automatic control device and a control method for contact force-to-displacement of electric spark deposition surfacing welding. The contact force between them is converted into the displacement of the floating sliding table, and the non-contact displacement sensor is used for detection, which realizes the transformation from tensile pressure measurement to displacement measurement, which not only improves the strength of the mechanical system, but also realizes the measurement of small contact force; according to the floating The displacement of the sliding table determines the contact force between the electrode and the workpiece, and the controller and the feeding mechanism are used to control the movement of the electrode along its axis to realize the closed-loop control of the contact force. The spring damping of the floating elastic mechanism can reduce the contact between the electrode and the workpiece. The vibration between the electrodes significantly improves the stability and reliability of the automatic control of the contact force between the electrode and the workpiece during the deposition process.

Description

Automatic control device and control method for electric spark deposition welding contact force to displacement

technical field

The invention relates to the technical field of electric spark deposition surfacing, in particular to an automatic control device and a control method for contact force-to-displacement of electric spark deposition surfacing.

Background technique

EDM is a processing method for removing materials. EDM deposition surfacing is a surface strengthening technology developed on the basis of EDM. It can deposit and surfacing special materials on the surface of workpiece materials, which can improve the hardness, Wear resistance, heat resistance, corrosion resistance, fatigue strength and service life, etc., can also repair surface defects such as scratches, pitting corrosion, and tolerances on the surface of precision mechanical parts.

Different from the EDM technology, the EDM deposition welding technology requires the electrode to be in constant contact with the workpiece for discharge and deposition welding. The process of EDM automatic deposition is that the electrode moves on the surface of the workpiece along a certain trajectory, and at the same time, it ensures that the electrode and the workpiece are continuously discharged and deposited in the state of contact, and the deposition layer is completed layer by layer. The contact state between the electrode and the workpiece directly affects its discharge mechanism and mass transfer mechanism, thereby affecting the quality and production efficiency of its deposited layer.

In the process of EDM deposition surfacing, the electrode and the workpiece need to be in constant contact. When the contact force between the electrode and the workpiece is different, the contact area between the electrode and the workpiece is also different. The size of the contact area directly affects the deposition process. The current density affects the discharge and mass transfer process, so the contact force has a greater impact on the contact state between the electrode and the workpiece.

EDM deposition welding technology has many advantages, but it is mainly used in the field of repair and has not been used in mass production. The reason is that the automation technology of EDM deposition welding has not been perfected and can only be completed manually; Not only is labor-intensive, but also the control of the contact force has a large randomness, which does not have reliability and stability, and cannot ensure the quality and production efficiency of the deposited layer; therefore, the automation of EDM deposition welding requires not only control electrodes and The relative motion trajectory between the workpieces and the control of the contact force between the electrode and the workpiece are also key.

In order to obtain a high-quality coating, the contact force between the electrode and the workpiece should not be too large, generally around 0.5N-2N; due to the unevenness of the contact surface between the electrode and the workpiece, and short-circuit bonding between the electrode and the workpiece, etc. , the relative movement of the electrode and the workpiece will generate a large vibration, and its impact force is sometimes much greater than its contact force, and the size and rigidity of this tiny force sensor are relatively small, which often leads to the force sensor used for contact force control. failure due to overload. Because the friction force of the sliding parts of the mechanical mechanism required to realize the automatic control of the contact force is greater than the contact force between the electrode and the workpiece, the control accuracy of the contact force is affected, and the control requirements cannot be met.

SUMMARY OF THE INVENTION

In view of the defects of the prior art, the purpose of the present invention is to provide an automatic control device and control method for the contact force to displacement of EDM deposition surfacing welding, which is used to solve the tiny contact between the electrode and the workpiece during the EDM deposition surfacing welding process. The problem of precise force control and electrode vibration can precisely control the contact force between the electrode and the workpiece and has the function of vibration reduction.

In order to achieve the above object, the technical scheme adopted in the present invention is:

An automatic control device for electric spark deposition welding contact force-to-displacement, including a mechanical system and an electric control system, the mechanical system includes a feeding mechanism, a floating elastic mechanism, a clamping gun mechanism and a welding gun; wherein, the feeding mechanism is mainly composed of The feed screw, the feed slide, and the feed base are composed; the floating elastic mechanism is mainly composed of an upper base, an optical axis, a linear bearing, a lower base, a spring, and a floating slide. The upper base and the lower base are parallel to each other. They are connected by an optical axis. The floating sliding table is set between the upper base and the lower base, and is passed through the optical axis through a linear bearing and can move up and down along the optical axis. The spring connects the floating sliding table and the upper base, and the upper base A non-contact displacement sensor is installed on the lower surface of the sliding table to measure the up and down displacement of the floating slide;

The mechanical system also includes an adjustment plate A, an adjustment plate B and an adjustment plate C, the gun clamping mechanism is installed on the side of the floating sliding table of the floating elastic mechanism through the adjustment plate C, and the floating elastic mechanism is installed on the sliding table of the feeding mechanism through the adjustment plate B. On the side of the table, the feeding mechanism is installed on the corresponding part of the EDM deposition welding device through the adjusting plate A, the welding gun is fixed on the clamping gun mechanism, and the electrode is installed on the welding gun; the axis and installation plane of the feeding mechanism and the welding gun are perpendicular to the horizontal plane; when When the angle between the welding torch and the workpiece changes, adjust by rotating the adjusting plate A, adjusting plate B and adjusting plate C, so that the axis of the feeding mechanism and the axis of the welding torch are always kept parallel, and the axis of the floating elastic mechanism is always kept vertical;

The electronic control system includes a controller, an A/D module, a displacement sensor, a stepping motor and a driver. The displacement sensor is connected to the controller through the A/D module. The controller stores the calibrated contact force-displacement table data. There is PID control software inside, the output interface of the controller is connected to the driver of the stepping motor, and the stepping motor is connected to the feeding mechanism.

Further, the included angle between the welding torch and the horizontally placed workpiece can be adjusted by a specific angle, and the specific angle includes: 0°, 15°, 30°, 45°, 60°, 75°, 90°.

Further, in the mechanical system, ignoring the frictional resistance of the optical axis to the floating slide, the relationship between the contact force between the electrode and the workpiece and the displacement of the floating slide is: F _Ni =k(z0-zi), where, z0 represents the displacement of the floating slide at time t0, that is, when the electrode workpiece is not in contact, zi represents the displacement of the floating slide at time ti, F _Ni represents the support force of the workpiece to the electrode at time ti, that is, the contact force between the electrode and the workpiece, k is The spring coefficient of the spring.

Further, when calibrating the contact force-displacement relationship, the supporting force of the workpiece to the electrode, that is, the contact force between the electrode and the workpiece, is directly measured by arranging a weighing sensor under the workpiece, and the displacement of the floating slide is obtained by measuring the displacement sensor. The contact force-displacement correspondence data is thus obtained and stored in the controller.

Using the above-mentioned control method of the automatic control device for the contact force to displacement of EDM deposition welding, the table data of the floating slide table displacement corresponding to the calibrated contact force is stored in the controller of the electronic control system, and the EDM deposition is set at the same time. The contact force required to be automatically maintained in the process; during the EDM deposition process, the controller continuously and periodically detects the input of the displacement sensor, and converts the displacement data into contact force according to the contact force-displacement corresponding data, and then contacts the set contact force. The force value is compared, and the difference value generates an output signal through the PID control software inside the controller. The driver controls the rotation of the stepper motor, and drives the welding torch and the electrode to move along its axis through the feeding mechanism. At this time, the electrode in contact with the workpiece pushes The floating sliding table moves accordingly, so that the contact force between the electrode and the workpiece changes accordingly, so as to realize the automatic closed-loop control of the contact force.

Beneficial effects:

1. In the present invention, a floating elastic mechanism is set between the feeding mechanism and the welding torch of the electric spark deposition surfacing, which skillfully converts the contact force between the electrode and the workpiece into the displacement of the floating sliding table, and uses a non-contact displacement sensor to detect the floating The displacement of the sliding table realizes the transformation from the tensile pressure measurement to the displacement measurement. After calibration, the contact force between the electrode and the workpiece can be determined according to the displacement of the floating sliding table, and the controller and the feeding mechanism are used to control the electrode to move along its axis. Motion, which realizes the closed-loop control of the contact force.

2. The present invention does not use a force sensor but a non-contact displacement sensor to measure the contact force, which not only improves the strength of the mechanical system, but also realizes the measurement of the tiny contact force, which significantly improves the performance of the automatic control device for the contact force between the electrode and the workpiece. reliability.

3. The floating elastic mechanism of the present invention adopts the ball linear bearing and the optical axis to cooperate, and has a small friction coefficient; the optical axis of the floating elastic mechanism is always in a vertical state, and the positive pressure between the floating sliding table and the optical axis is also small, so that the The friction force between the floating slide and the optical axis is very small, so as to ensure the automatic control of the tiny contact force between the electrode and the workpiece, and the control accuracy of the contact force can reach 0.5N.

4. The floating elastic mechanism of the present invention has a vibration damping function, and its spring damping can reduce the vibration between the electrode and the workpiece and improve the stability of the deposition process.

5. The present invention can stepwise adjust the angle between the electrode and the workpiece. When adjusting the included angle, the optical axis of the floating elastic mechanism is always in a vertical state, and the axis of the feeding mechanism is always parallel to the axis of the welding torch and the electrode. When the electrode is worn out, the controller and the feeding mechanism drive the welding torch to move forward along the axis of the welding torch, which can not only keep the contact force stable, but also keep the contact position between the electrode and the workpiece unchanged, which ensures the movement of the electrode during the automatic deposition process. control precision.

Description of drawings

Fig. 1 is the overall schematic diagram of the present invention;

Figure 2 is the force diagram of the floating elastic mechanism when the welding torch is not in contact with the workpiece;

Fig. 3 is the force diagram of the floating elastic mechanism during the contact force of the present invention--displacement calibration;

Fig. 4 is the contact force closed-loop control principle diagram of the present invention;

5 is a schematic diagram of a mechanical part of a specific embodiment of the present invention;

FIG. 6 is a front view of a specific embodiment of the present invention when the welding torch is vertical to the workpiece.

Reference numerals: 1. Feeding mechanism, 2. Adjusting plate A, 3. Adjusting plate B, 4. Spring, 5. Upper base, 6. Displacement sensor, 7. Clamping mechanism, 8. Adjusting plate C, 9, Floating slide, 10, Lower base, 11, Welding torch, 12, Motor, 13, Work piece, 14, Optical axis, 15, Linear bearing, 16, Electric control system, 17, Stepper motor, 18, Load cell, 19 , column, 20, base, 21, X-axis slide, 22, Y-axis slide, 23, Z-axis slide.

Detailed ways

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

As shown in Fig. 1, an automatic control device for electric spark deposition welding contact force to displacement is mainly composed of a mechanical system and an electronic control system 16, wherein the mechanical system includes a feeding mechanism 1, a floating elastic mechanism, and a clamping gun mechanism 7 and the welding torch 11; the feeding mechanism 1 is mainly composed of a feeding screw, a feeding slide table, and a feeding base. The feeding screw is arranged on the feeding base, and the feeding slide is driven by the rotation of the feeding screw. The platform moves; the floating elastic mechanism is mainly composed of an upper base 5, an optical axis 14, a linear bearing 15, a lower base 10, a spring 4, and a floating slide 9. The upper base 5 and the lower base 10 are parallel to each other, and the left and right The two right optical axes 14 are connected (the optical axis in the present invention refers to an axis with a smooth surface), the floating slide 9 is arranged between the upper base 5 and the lower base 10, and is passed through the optical axis 14 through the linear bearing 15 and can be Moving up and down along the optical axis 14 , the spring 4 connects the floating slide 9 and the upper base 5 .

The mechanical system also includes an adjustment plate A2, an adjustment plate B3 and an adjustment plate C8, and the adjustment plate A2, the adjustment plate B3, and the adjustment plate C8 are all vertically arranged, wherein the gun clamping mechanism 7 is installed on the floating elastic mechanism through the adjustment plate C8. On the side of the sliding table 9, the angle of the gun clamping mechanism 7 can be adjusted by rotating the adjusting plate C8; the floating elastic mechanism is installed on the side of the feeding sliding table of the feeding mechanism 1 through the adjusting plate B3, and the angle of the floating elastic mechanism can be adjusted by rotating the adjusting plate B3 , the feeding mechanism 1 is installed on the corresponding part of the EDM deposition welding device through the adjusting plate A2, and the angle of the feeding mechanism 1 can be adjusted by rotating the adjusting plate A2; the welding gun 11 is fixed on the clamping gun mechanism 7, and the electrode 12 is installed on the welding gun 11 , the angle between the welding torch 11 and the horizontally placed workpiece 13 can be adjusted by a specific angle, the specific angle includes: 0°, 15°, 30°, 45°, 60°, 75°, 90°.

The axes and installation planes of the feeding mechanism 1 and the welding torch 11 are both perpendicular to the horizontal plane. When the angle between the welding torch 11 and the workpiece 13 changes, adjust by rotating the adjustment plate A2, the adjustment plate B3 and the adjustment plate C8 to make the feeding The axis of the mechanism 1 is always kept parallel to the axis of the welding torch 11, and the optical axis 14 of the floating elastic mechanism is always kept vertical.

The electronic control system 16 is mainly composed of a controller, an A/D module, a displacement sensor 6, a stepping motor 17 and its driver. The displacement sensor 6 is connected to the controller through the A/D module, and the controller stores the calibrated contact force-displacement Table data, PID control software is provided in the controller, the output interface of the controller is connected to the driver of the stepping motor 17, the stepping motor 17 is connected to the feeding mechanism 1, and the feeding screw is driven to drive the feeding slide to move. Communication connection with the host computer.

2 is the force diagram of the floating elastic mechanism when the electrode 12 is not in contact with the workpiece 13 in the present invention. At time t0, the electrode 12 on the welding torch 11 is not in contact with the workpiece 13. Under the action of gravity, the welding torch 11 and the floating slide 9 will move downward. When the elastic force of the spring 4, the friction between the floating slide 9 and the two optical axes 14, and the gravity of the welding torch 11 and the floating slide 9 reach a balance, the force balance formula is:

G=F _p0 +F _fL0 +F _fR0 =kΔx0+F _fL0 +F _fR0 (1)

In formula (1): G is the gravity of the floating parts such as the welding torch and the floating slide, F _p0 is the pulling force of the spring on the floating slide at t0, F _fL0 is the frictional resistance of the left optical axis to the floating slide at t0, F _fR0 is the frictional resistance of the right optical axis to the floating slide at time t0, k is the elastic coefficient of the spring, and Δx0 is the elongation of the spring at time t0.

At this time, the length of the spring under tension is x0, and the displacement of the floating slide detected by the displacement sensor is z0.

3 is the contact force of the present invention—the force diagram of the floating component during displacement calibration; at time ti, the electrode 12 on the welding torch 11 is in contact with the workpiece 13, and the contact force between the electrode 12 and the workpiece 13 is the upward support of the workpiece 13 to the electrode 12 force, the formula to reach the force balance at this time is:

G=F _Ni +F _pi +F _fLi +F _fRi =F _Ni +kΔxi+F _fLi +F _fRi (2)

In formula (2): F _Ni is the support force of the workpiece to the electrode at time ti, F _pi is the pulling force of the spring on the floating slide at time ti, F _fLi is the frictional resistance of the left optical axis to the floating slide at time ti, F _fRi is the frictional resistance of the right optical axis to the floating slide at time ti, and Δxi is the elongation of the spring at time ti.

At this time, the length of the spring under tension is xi, and the displacement of the floating slide detected by the displacement sensor is zi.

Subtracting equation (2) from equation (1) can get:

F _Ni =k(Δx0-Δxi)+(F _fL0 +F _fR0 )-(F _fLi +F _fRi ) (3)

=k(x0-xi)+(F _fL0 +F _fR0 )-(F _fLi +F _fRi )

=k(z0-zi)+(F _fL0 +F _fR0 )-(F _fLi +F _fRi )

A ball linear bearing is used between the floating sliding table 9 and the optical axis 14 of the floating elastic mechanism of the present invention, and the friction coefficient between the floating sliding table 9 and the optical axis 14 is small, about 0.002-0.003; considering the assembly problem, the two optical axes 14 The friction coefficient to the floating slide 9 is about 0.01; since the optical axis 14 of the floating elastic mechanism is vertically arranged, the positive pressure between the linear bearing 15 and the optical axis 14 is also very small (less than 10N), so the two optical axes are The frictional resistance of 14 to the floating slide 9 is not greater than 0.1N, which can be ignored, then formula (3) can be simplified as:

F _Ni = k(z0-zi) (4)

That is, the supporting force F _Ni of the workpiece 13 to the electrode 12 depends on the displacement zi of the floating slide 9 , and the contact force between the workpiece 13 and the electrode 12 corresponds to the displacement of the floating slide 9 one-to-one.

As shown in Fig. 3, when calibrating, the load cell 18 is installed under the workpiece 13 where the electrode 12 and the workpiece 13 are in contact, and the supporting force of the workpiece 13 to the electrode 12 is directly measured, that is, the contact force between the electrode 12 and the workpiece 13, and the displacement is at the same time. The sensor 6 measures the displacement of the floating slide 9, and the corresponding relationship between the contact force and the displacement of the floating slide 9 can be obtained, as shown in Table 1 below.

Table 1 Displacement of floating slide 9 corresponding to different contact forces

Fig. 4 is the contact force closed-loop control principle diagram of the present invention, and the automatic control method of the contact force in the process of EDM deposition surfacing by using the automatic control device of the present invention is as follows: the displacement table of the floating slide corresponding to the calibrated contact force The data is stored in the controller while setting the contact force required to automatically maintain the EDM process. During the EDM deposition process, the controller continuously and periodically detects the input of the displacement sensor, converts the displacement into the contact force according to the contact force-displacement correspondence table data, and then compares it with the set contact force value, and the difference is passed through the PID The control software generates an output signal, the driver controls the rotation of the stepper motor, and drives the welding torch and the electrode to move along its axis through the feeding mechanism. At this time, the workpiece in contact with the electrode pushes the elastic slide table to move accordingly, resulting in The contact force between the workpieces changes accordingly, thereby realizing the automatic closed-loop control of the contact force.

For example, the controller obtains the displacement of the floating slide table in real time through the non-contact displacement sensor, and the contact force between the electrode and the workpiece can be obtained through the corresponding relationship between the contact force and the displacement. During the process of EDM deposition surfacing, the floating slide moves down due to the loss of the electrode or the drop of the surface of the workpiece, so that the contact force decreases and is less than the set value, the controller generates an output signal through the driver and the stepper. The feeding motor drives the feeding sliding table of the feeding mechanism, the floating elastic mechanism and the welding gun installed on it to move forward along the axis of the feeding mechanism and the welding gun, which will cause the floating sliding table to move up and reduce the displacement of the floating sliding table. That is, the contact force between the electrode and the workpiece is increased to reach the set contact force value, and the automatic closed-loop control of the contact force is realized.

Fig. 5 is a schematic diagram of a mechanical part of a specific embodiment of the present invention, wherein Fig. 5(b) is a right side view of Fig. 5(a). Control device, among which, the three-dimensional numerical control device is mainly composed of X-axis slide table 21, Y-axis slide table 22, Z-axis slide table 23, column 19, base 20 and numerical control system, etc. The workpiece 13 is installed on X-axis slide table 21 and Y-axis slide table 21 On the XY-axis cross sliding table composed of the axis sliding table 22, the automatic control device for the contact force and displacement of the EDM deposition welding of the present invention is installed on the Z-axis sliding table 23 of the three-dimensional numerical control device through the adjusting plate A2; The electrical parameters of the deposition are set on the surfacing welding power source, and the three-dimensional numerical control device is responsible for controlling the start and stop of the electric spark discharge and the movement track of the electrode 12 relative to the surface of the workpiece 13 during the automatic spark deposition surfacing process. The automatic control device of the present invention is responsible for Controls the contact force between the electrode 12 and the workpiece 13 during automated deposition.

Among them, the displacement sensor 6 is an Omron Z4W-V25 laser displacement sensor, and the measurement accuracy can reach 10 μm. The non-contact displacement sensor is installed on the upper base 5 of the floating elastic mechanism through the sensor bracket, which can realize the non-contact displacement of the elastic sliding table. Measurement; select an electronic scale with an accuracy of 0.001g to measure the supporting force between the electrode 12 and the workpiece 13, calibrate the corresponding relationship between the contact force and the displacement of the floating slide 9, and obtain the floating slide 9 corresponding to different contact forces Displacement table data.

Feed mechanism 1 selects Shangyin KK50 lead screw slide module, stepper motor 17 selects Lexay 42CM08 stepper motor, and its driver selects Lexel DM422S driver; the controller selects domestic LK-32MT type PLC, the PLC It has 10 AD inputs, which can be connected to the output of the displacement sensor 6 to obtain the displacement data of the floating slide 9; the PLC has 4 high-speed outputs, which can output pulse signals and connect to the input of the stepping motor 17 driver to control the feeding mechanism 1 Rotation of the stepping motor 17.

Under the control of the three-dimensional numerical control system, the Z-axis slide table 23 controls the welding torch 11 to move down, so that the electrode 12 is in contact with the surface of the workpiece 13, and the spark discharge pulse is turned on. Movement, point by line, layer by layer deposition surfacing to form a deposition layer, so as to realize automatic EDM deposition surfacing. In the process of automatic spark deposition, when the electrode 12 is consumed or the surface of the workpiece 13 is uneven and the contact force changes, the device of the present invention can control the automatic feeding of the electrode 12 and automatically control the contact force between the electrode 12 and the workpiece 13 The setting value is always maintained, and the specific control process is shown in FIG. 4 . FIG. 6 is a front view of the welding torch 11 when the workpiece 13 is vertical, that is, the angle between the welding torch 11 and the horizontally placed workpiece 13 is 90°.

The automatic control device of the present invention is a system that can work independently. In actual use, it can be installed on other mechanical devices (such as robots) in addition to the three-dimensional numerical control device.

The invention adopts a floating elastic mechanism, and the change of the contact force between the electrode and the workpiece corresponds to the displacement change of the floating sliding table one-to-one. The contact force is indirectly measured by measuring the displacement of the floating sliding table, and the movement of the floating elastic mechanism is controlled by the feeding mechanism. To adjust the contact force between the electrode and the workpiece, so as to realize the closed-loop control of the contact force, and realize the precise control of the tiny contact force (0.5N-2N) between the electrode and the workpiece, and the floating elastic mechanism can damp the vibration of the electrode. Vibration reduction, the feeding mechanism compensates for the change of the contact force after the electrode is consumed to ensure the stability of the contact force and the unchanged deposition position, thereby ensuring the quality of the automatic spark deposition.

The above are only preferred embodiments of the present invention, and do not limit the present invention in any form. Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. The technical personnel, within the scope of the technical solution of the present invention, can make some changes or modifications by using the technical content disclosed above to be equivalent examples of equivalent changes, but if they do not depart from the technical solution content of the present invention, according to the present invention Any simple modifications, equivalent changes and modifications made to the above embodiments still fall within the scope of the technical solutions of the present invention.

Claims (3)

1. An automatic control device for contact force-to-displacement conversion of electric spark deposition surfacing welding comprises a mechanical system and an electric control system, and is characterized in that the mechanical system comprises a feeding mechanism, a floating elastic mechanism, a gun clamping mechanism and a welding gun; the feeding mechanism mainly comprises a feeding screw rod, a feeding sliding table and a feeding base; the floating elastic mechanism mainly comprises an upper base, an optical axis, a linear bearing, a lower base, a spring and a floating sliding table, wherein the upper base and the lower base are parallel to each other and are connected through the optical axis;

the mechanical system further comprises an adjusting plate A, an adjusting plate B and an adjusting plate C, the gun clamping mechanism is installed on the side face of a floating sliding table of the floating elastic mechanism through the adjusting plate C, the floating elastic mechanism is installed on the side face of a feeding sliding table of the feeding mechanism through the adjusting plate B, the feeding mechanism is installed on the corresponding position of the electric spark deposition surfacing welding device through the adjusting plate A, the welding gun is fixed on the gun clamping mechanism, and an electrode is installed on the welding gun; when the included angle between the welding gun and the workpiece is changed, the axis of the feeding mechanism and the axis of the welding gun are always kept parallel by rotating the adjusting plate A, the adjusting plate B and the adjusting plate C for adjustment, and the axis of the floating elastic mechanism is always kept vertical;

in the mechanical system, neglecting the frictional resistance of the optical axis to the floating sliding table, the relation between the contact force of the electrode and the workpiece and the displacement of the floating sliding table is as follows:

wherein, in the step (A), z0 represents the displacement of the floating slide at time t0 when the electrode workpiece is not in contact,zi denotes the displacement of the floating ramp at time ti,F _Nithe support force of the workpiece on the electrode at the moment ti, namely the contact force between the electrode and the workpiece, is represented, and k is the elastic coefficient of the spring;

when the relation of contact force-displacement is calibrated, a weighing sensor is arranged below a workpiece to directly measure the supporting force of the workpiece to an electrode, namely the contact force between the electrode and the workpiece, and the displacement of a floating sliding table is obtained through measurement of a displacement sensor, so that contact force-displacement corresponding data is obtained and stored in a controller;

the electric control system comprises a controller, an A/D module, a displacement sensor, a stepping motor and a driver, wherein the displacement sensor is connected with the controller through the A/D module, calibrated contact force-displacement table data are stored in the controller, PID control software is arranged in the controller, an output interface of the controller is connected with the driver of the stepping motor, and the stepping motor is connected with a feeding mechanism.

2. An automatic control device for contact force-to-displacement of electric spark deposition overlaying welding according to claim 1, wherein an included angle between a welding gun and a horizontally placed workpiece can be adjusted by a specific angle, and the specific angle comprises: 0 °, 15 °, 30 °, 45 °, 60 °, 75 °, 90 °.

3. The control method of the automatic control device for the contact force-to-displacement rotation of the electric spark deposition overlaying welding according to claim 1, characterized by comprising the following steps of: storing the displacement table data of the floating sliding table corresponding to the calibrated contact force in a controller of an electric control system, and setting the contact force required to be automatically maintained in the electric spark deposition process; in the electric spark deposition process, a controller continuously and periodically detects the input of a displacement sensor, the displacement data is converted into contact force according to contact force-displacement corresponding data, the contact force is compared with a set contact force value, the difference value of the contact force and the displacement is compared with an output signal generated by PID control software in the controller, a driver controls the rotation of a stepping motor, a feeding mechanism drives a welding gun and an electrode to move along the axis of the welding gun and the electrode, the electrode in contact with a workpiece pushes a floating sliding table to move correspondingly at the moment, so that the contact force between the electrode and the workpiece is changed correspondingly, and the automatic closed-loop control of the contact force is realized.

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