Ink direct writing equipment integrated with high-precision force feedback

Abstract

The invention discloses ink direct writing equipment integrating high-precision force feedback, which comprises a movement mechanism, an extrusion mechanism and a control system, and is characterized in that the movement mechanism is a three-axis gantry platform and is driven by the combination of a stepping motor and a slide rail to realize the movement of a preset track, a preset speed and the like in a space. And the extrusion mechanism is fixed on the Z axis of the motion platform and is formed by coaxially connecting and combining an injector, an actuator for driving a push rod of the injector and a high-precision tension and pressure sensor in series. The force sensor is directly integrated into a transmission path of extrusion thrust, so that direct measurement and closed-loop control of printing force are realized, the problem of unstable extrusion caused by factors such as ink viscosity change, needle blockage or substrate unevenness is solved from the aspect of structural design, and the precision and consistency of printed finished products are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of additive manufacturing technology, in particular to a direct ink writing device integrated with high-precision force feedback and a method thereof. BACKGROUND

[0002] Direct ink writing (DIW) is an important additive manufacturing technology, which builds three-dimensional solid structures by precisely controlling the movement path of the printing nozzle and extruding high-viscosity "ink" (such as ceramic slurry, hydrogel, metal paste, epoxy resin, etc.) from the nozzle in a layer-by-layer manner. This technology has wide application prospects in the fields of biological manufacturing, flexible electronics, microfluidic chips, and structure-function integrated devices.

[0003] The existing direct ink writing device usually uses pneumatic control or mechanical open-loop control for its extrusion mechanism. Pneumatic control pushes the piston in the needle cylinder by adjusting the air pressure to achieve ink extrusion. This method has slow response speed, and the stability and accuracy of air pressure are easily affected by air source fluctuations and pipe length, making it difficult to achieve precise control of extrusion force.

[0004] Mechanical open-loop control, such as using a stepper motor to drive a lead screw to push the needle cylinder piston, is relatively accurate in displacement control, but it is essentially an open-loop control based on displacement or speed. It cannot sense the actual extrusion resistance changes during printing. In actual printing, the viscosity of the ink may change due to temperature, humidity, or curing reaction; the printing nozzle may be partially blocked; and the printing substrate may be uneven. These factors can cause the actual extrusion pressure to fluctuate dramatically. Under open-loop control, this fluctuation cannot be compensated, resulting in uneven printing line width, unstable material deposition, and other problems, which seriously affect the precision, quality, and consistency of the final product.

[0005] Existing direct ink writing devices generally use pneumatic control or mechanical open-loop control. The pneumatic system has slow response and pressure is easily affected by air source fluctuations; the open-loop mechanical system (such as a stepper motor push rod) can accurately control displacement, but cannot sense actual extrusion resistance changes. When the viscosity of the ink changes, the nozzle is blocked, or the substrate is uneven, the extrusion pressure fluctuates dramatically, resulting in uneven printing line width, unstable material deposition, and seriously affecting printing precision and consistency.

[0006] Therefore, there is an urgent need in the art for a direct ink writing technology solution that can overcome the above-mentioned defects and achieve precise, stable, and closed-loop feedback control of the extrusion process. SUMMARY

[0007] To solve the above technical problems, the present application adopts the following technical solutions.

[0008] An ink direct writing device integrated with high-precision force feedback, comprising:

[0009] A three-axis motion platform for driving an extrusion mechanism to move along a predetermined trajectory in a three-dimensional space;

[0010] An extrusion mechanism fixed to the Z-axis of the three-axis motion platform, comprising a syringe, an electric actuator, and a force sensor;

[0011] A control system electrically connected to the three-axis motion platform, the electric actuator, and the force sensor;

[0012] The force sensor is coaxially arranged in series between the output end of the electric actuator and the push rod of the syringe, for real-time measurement of the actual extrusion force applied to the push rod.

[0013] Optionally, the force sensor is a tension and compression force sensor or a strain gauge type force sensor.

[0014] Optionally, the electric actuator is a lead screw actuator, including an internally integrated motor and a lead screw.

[0015] Optionally, one end of the force sensor is rigidly connected to the linear slider of the electric actuator through a fixing member, and the other end is rigidly connected to the tail of the push rod.

[0016] Optionally, the control system comprises:

[0017] A main control unit for arithmetic processing and control instruction generation;

[0018] A force signal acquisition module for acquiring analog or digital signals output by the high-precision force sensor;

[0019] A motion control module for controlling the motor drive of the three-axis motion platform;

[0020] An extrusion control module for independently controlling the motor drive of the electric actuator.

[0021] A constant force ink direct writing printing method based on an ink direct writing device integrated with high-precision force feedback, comprising the following steps:

[0022] S1: Set the target extrusion force value in the control system;

[0023] S2: Control the three-axis motion platform to move the printing needle of the extrusion mechanism along a predetermined three-dimensional trajectory;

[0024] S3: Drive the electric actuator to push the push rod to extrude ink, while continuously measuring the actual force applied to the push rod through the high-precision force sensor;

[0025] S4: Real-time comparison of the measured actual thrust with the target extrusion thrust value, obtaining a thrust error;

[0026] S5: According to the thrust error, dynamically adjusting the operating parameters of the electric actuator through a closed-loop feedback control algorithm, minimizing the error between the actual thrust and the target extrusion thrust value, and realizing constant force extrusion printing.

[0027] Optionally, the closed-loop feedback control algorithm is a PID control algorithm, which outputs a control quantity by calculating proportional, integral and differential terms, and the control quantity is mapped to the motor pulse frequency of the electric actuator, and the motor speed is adjusted by adjusting the pulse frequency to adjust the thrust.

[0028] Compared with the prior art, the present application has the following beneficial technical effects:

[0029] 1. High-precision constant force extrusion is realized: the thrust is directly measured by a force sensor and closed-loop feedback, and the control precision is significantly better than that of traditional schemes;

[0030] 2. Improve printing consistency and product quality: uniform line width and height, tight interlayer bonding, suitable for high-precision functional structure manufacturing;

[0031] 3. Compact and reliable structure: coaxial integrated design, good rigidity, easy installation, low maintenance cost, and good engineering practicability. BRIEF DESCRIPTION OF DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description.

[0033] Figure 1 Fig. 1 is a schematic diagram of the overall structure of an ink direct writing device integrated with force feedback in an embodiment of the present application;

[0034] Figure 2 Fig. 2 is an enlarged structural schematic diagram of each component of the extrusion mechanism in an embodiment of the present application;

[0035] Figure 3 Fig. 3 is a front view and a side view of the constant force extrusion mechanism;

[0036] Figure 4 Fig. 4 is an enlarged front view of the constant force extrusion mechanism;

[0037] Figure 5 Fig. 5 is an enlarged side view of the constant force extrusion mechanism;

[0038] Figure 6 Fig. 6 is a comparison diagram of the printing effect of the transmission pneumatic ink direct writing device and the present patent; wherein Figure 6Fig. 1 (a) is a printing effect of a transmission pneumatic ink direct writing device, Figure 6 Fig. 1 (b) is a printing effect comparison chart of the patent;

[0039] Figure 7 Fig. 1 (c) is a logic block diagram of a constant force closed-loop control system in an embodiment of the present application;

[0040] 1, force sensor; 2, syringe push rod; 3, syringe barrel; 4, needle; 5, 6 clamp; 7, fixing piece; 8, bracket; 9, electric actuator; 10, lead screw; 11, linear slide; 12, Z-axis assembly; 13, slide; 14, X-axis assembly; 15, Y-axis assembly; 16, screw. DETAILED DESCRIPTION

[0041] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Figures 1 to 7 The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application.

[0042] In an embodiment, the present application provides an ink direct writing device integrated with high-precision force feedback, comprising:

[0043] A three-axis motion platform for driving the extrusion mechanism to move along a predetermined trajectory in a three-dimensional space;

[0044] An extrusion mechanism fixed to the Z-axis of the three-axis motion platform, comprising a syringe, an electric actuator and a force sensor;

[0045] A control system electrically connected to the three-axis motion platform, the electric actuator and the force sensor;

[0046] The force sensor is coaxially connected in series between the output end of the electric actuator and the push rod of the syringe, for real-time measurement of the actual extrusion thrust applied to the push rod.

[0047] Optionally, the force sensor is a tensile and compressive force sensor or a strain gauge type force sensor.

[0048] Optionally, the electric actuator is a lead screw actuator, including an internally integrated motor and a lead screw.

[0049] Optionally, one end of the force sensor is rigidly connected to the linear slide of the electric actuator through a fixing piece, and the other end is rigidly connected to the tail of the push rod.

[0050] Optionally, the control system comprises:

[0051] A main control unit for arithmetic processing and control instruction generation;

[0052] a force signal collection module for collecting analog or digital signals output by the high-precision force sensor;

[0053] a motion control module for controlling motor driving of the three-axis motion platform;

[0054] an extrusion control module for independently controlling motor driving of the electric actuator.

[0055] In another embodiment, referring to Figure 1 The application provides a direct ink writing device integrated with high-precision force feedback, mainly comprising a three-axis motion platform, an extrusion mechanism, and a control system.

[0056] The three-axis motion platform comprises an X-axis assembly, a Y-axis assembly, and a Z-axis assembly.

[0057] Each axis is driven by a stepper motor through coupling, a lead screw, a slide rail, and other transmission components, and can drive the extrusion mechanism to perform high-precision trajectory motion in three-dimensional space under the instruction of the control system.

[0058] Specifically, an X-Y-Z gantry can be used, the X axis and the Y axis form a horizontal moving plane, and the Z axis is vertically installed on the cross beam.

[0059] Each axis uses a NEMA 23 stepper motor (such as 57HS22) in combination with a ball screw (lead 5 mm) and a linear guide rail (such as HIWIN MGN12).

[0060] Positioning accuracy: ±5 μm, repeat positioning accuracy: ±2 μm.

[0061] Stroke range: X: 200 mm, Y: 200 mm, Z: 100 mm.

[0062] Mounting interface: a standard flange (such as Φ30 mm) is arranged on the Z-axis slide table for fixing the extrusion mechanism.

[0063] Referring to Figure 1 and Figure 2 The extrusion mechanism is fixed on the slide block (13) of the Z-axis assembly (12) through a fixing member (7) and a screw (16), and comprises a syringe (2, 3, 4), an electric actuator (9), and a force sensor (1).

[0064] The syringe is a standard syringe, comprising a needle cylinder (such as 3 ml, 5 ml, 10 ml, etc.) (3) for containing printing ink and a push rod (2) that can slide in the needle cylinder; the front end of the needle cylinder is configured with a bayonet type 1 / 4 stainless steel needle (4) with different inner diameters, which can be replaced according to actual printing requirements.

[0065] The electric actuator can adopt a screw actuator (such as a linear module stepping motor, thrust range 0-200 N), an internal integrated motor (step angle 1.8°) and a screw (lead 2 mm), which converts the rotary motion into linear thrust.

[0066] The force sensor is mounted between the actuator output end and the syringe push rod, and the sensor is rigidly connected with the tail of the push rod and the actuator slider through a threaded interface, so as to ensure that the coaxiality deviation is less than 0.1 mm.

[0067] For example, the force sensor is preferably a high-precision tension and compression force sensor or a strain gauge type force sensor, which can accurately measure the actual thrust F_actual applied to the push rod by the screw actuator.

[0068] Model example: HBM U9C or Futek LSB200;

[0069] Range: 0-20 N (0-10 N or 0-50 N can be selected according to the viscosity of the ink);

[0070] Accuracy: ±0.1% FS;

[0071] Output signal: analog voltage (0-5 V) or digital RS485 (analog output is used in this embodiment)

[0072] The assembly relationship is as follows:

[0073] The electric actuator, the force sensor and the syringe push rod are coaxially connected along the thrust action direction.

[0074] Specifically, the force sensor is arranged between the output end of the electric actuator and the syringe push rod, so as to measure the actual thrust applied to the push rod in real time and directly during printing. One end of the force sensor is connected with the linear slider (11) of the screw actuator through a fixing member, and the other end is fixedly connected with the tail of the syringe push rod.

[0075] The control system is electrically connected with the three-axis motion platform, the electric actuator of the extrusion mechanism and the force sensor. The control system is configured to receive the real-time thrust signal from the force sensor, compare the signal with a preset target force value, and according to the deviation generated by the comparison, adjust the operating parameters (such as the rotation speed of the motor) of the electric actuator in real time through a closed-loop feedback control algorithm (such as PID control), so as to make the actual thrust applied to the push rod dynamically approach and stabilize at the preset target force value.

[0076] For example, the control system includes:

[0077] Master unit: embedded controller based on ARM Cortex-M7 (e.g. STM32H743) or industrial PC (running LinuxCNC);

[0078] As a preferred embodiment, esp32 development board is adopted;

[0079] Motion control: three-axis platform motor is controlled by TMC2209 step drive chip, supporting micro-step subdivision (1 / 256);

[0080] Extrusion control: independent control of lead screw actuator motor, also using TMC driver;

[0081] Force signal acquisition: 16-bit ADC (e.g. ADS1115) acquires sensor analog voltage signal, sampling frequency ≥1 kHz;

[0082] Human-machine interface: 7-inch touch screen, running Qt interface, supporting: setting target thrust value (e.g. 8.5 N); uploading G-code file; real-time display of actual thrust curve, motor speed, printing progress;

[0083] Closed-loop algorithm: discrete PID controller, parameters adjustable (Kp=2.0, Ki=0.1, Kd=0.05 as initial value);

[0084] Control logic:

[0085] Controller calculates error e(k) = F_set - F_actual(k);

[0086] Output control variable u(k) = Kp·e(k) + Ki·Σe(i) + Kd·[e(k)-e(k-1)];

[0087] Map u(k) to actuator motor pulse frequency (e.g. 0-10 kHz corresponds to 0-1000 rpm);

[0088] Adjust motor speed dynamically by adjusting pulse frequency, thereby adjusting thrust.

[0089] In another embodiment, the present application provides a direct ink writing device integrated with high-precision force feedback, comprising: a three-axis motion platform, an extrusion mechanism, and a control system;

[0090] Referring to Figure 1 and Figure 3 , the extrusion mechanism is installed on the Z-axis slider (13) of the three-axis gantry platform as an independent module through the fixing piece (7) and the screw (16), as shown in Figure 1The installation mode ensures that the extrusion mechanism can move vertically along the Z axis and cooperates with the X and Y axes to complete the printing path in three-dimensional space.

[0091] The extrusion mechanism coaxially connects the electric actuator (9), the force sensor (1), and the syringe push rod (2) along the direction of the thrust force, which is a key structure for realizing high-precision force feedback.

[0092] The electric actuator (9) is located at the uppermost position, preferably a screw actuator, which integrates a motor and a screw inside to convert rotary motion into linear thrust force, and the output end is connected to a linear slider (11).

[0093] The force sensor (1) is located below the electric actuator, one end of which is rigidly connected to the linear slider (11) of the actuator through a fixing member, and the other end is rigidly connected to the tail of the syringe push rod (2); the force sensor is accurately placed in the thrust transmission path for real-time measurement of the actual thrust force applied to the push rod.

[0094] The syringe push rod (2) is located below the force sensor, the tail of which is connected to the force sensor, and the push rod slides in the syringe barrel (3), and the front end pushes the ink out of the needle (4). The syringe push rod (2) extends downward through the sensor 1, the needle barrel (3) is fixed in the bracket (8) by the clamps (5, 6), and the needle (4) is located at the bottom. The fixing member (7) extends upward from the top of the bracket (8) for connecting the Z axis.

[0095] The syringe barrel (3) is used to contain the printing ink, and the bottom is fixed on the bracket (8) by the clamps (5, 6). The front end of the needle barrel is connected with a bayonet type stainless steel needle (4), which can be replaced according to the requirement of different inner diameter.

[0096] The bracket (8) is the main frame of the entire extrusion mechanism, which is used to fix the syringe barrel (3) and the clamps (5, 6) and provide structural support.

[0097] The fixing member (7) is an L-shaped or similar connecting plate, one end of which is fixed on the Z-axis slider, and the other end is connected to the top of the bracket (8), so as to firmly install the entire extrusion mechanism on the moving platform.

[0098] Referring to Figure 4 and Figure 5 , the syringe push rod (2) passes through the center hole of the force sensor (1) and enters the needle barrel (3); the clamps (5, 6) are fixed on the bracket (8) by screws and clamp the needle barrel (3).

[0099] In another embodiment, the present application provides a constant force ink direct writing printing method based on an integrated high-precision force feedback ink direct writing device, comprising the following steps:

[0100] S1: setting a target extrusion thrust value in the control system;

[0101] S2: controlling the three-axis motion platform to move the printing needle of the extrusion mechanism along a predetermined three-dimensional trajectory;

[0102] S3: driving the electric actuator to push the push rod to extrude ink, while continuously measuring the actual thrust applied to the push rod through the high-precision force sensor;

[0103] S4: comparing the measured actual thrust with the target extrusion thrust value in real time to obtain a thrust error;

[0104] S5: dynamically adjusting the operating parameters of the electric actuator according to the thrust error through a closed-loop feedback control algorithm to minimize the error between the actual thrust and the target extrusion thrust value, and realizing constant force extrusion printing.

[0105] Optionally, the closed-loop feedback control algorithm is a PID control algorithm, which outputs a control quantity by calculating a proportional term, an integral term, and a differential term, the control quantity is mapped to the motor pulse frequency of the electric actuator, and the thrust is adjusted by adjusting the pulse frequency to change the motor speed.

[0106] In another embodiment, the present application also provides a constant force ink direct writing printing method based on the above-mentioned device, comprising the following steps:

[0107] Step S1: device preparation: install the syringe into the extrusion mechanism, connect the tail of the push rod to the force sensor to ensure that there is no looseness; fix the extrusion mechanism to the Z-axis sliding table, adjust the height of the Z-axis to adjust the distance between the needle tip and the substrate;

[0108] Step S2: setting the parameters of the printing device: set the target thrust F_set on the touch screen interface; set the three-axis platform motion speed; load the G code file, the path is a straight line (X: 0→20 mm, Y=0, Z constant); start the PID controller and set the sampling period;

[0109] Step S3: printing execution: the control system starts the three-axis platform, and the nozzle moves uniformly along the X-axis; at the same time, the actuator motor starts at an initial frequency (such as 2 kHz) to push the push rod to extrude ink; the force sensor outputs a voltage signal in real time, which is converted to F_actual through ADC;

[0110] During the extrusion process, the force sensor feeds back the measured actual thrust F_actual to the control system in real time as an electrical signal (such as a voltage signal). The closed-loop control algorithm inside the control system (such as a PID controller) compares F_actual with the preset F_set to obtain the error e = F_set - F_actual. Then, the controller adjusts the output to the drive motor in real time (e.g., increases or decreases the frequency of the drive pulse) according to the magnitude and sign of the error e, thereby changing the thrust of the lead screw actuator so that F_actual is quickly adjusted to be equal to F_set.

[0111] During the printing process, if the ink solidifies locally, causing increased resistance, the system automatically reduces the frequency, causing the thrust to drop; it maintains constant force throughout the process, ensuring stable extrusion flow and forming uniform lines.

[0112] Reference Figure 6 A comparison of printing results between the pneumatic ink direct writing device and this method; among them... Figure 6 Image (a) shows the printing effect of the pneumatic ink direct writing device. Figure 6 Image (b) shows the printed effect of this patent. Figure 6 (a) has problems with broken lines and uneven height and thickness during the printing process, and the printed height is much higher than expected and there are sudden changes in thickness; Figure 6 (b) By integrating a force sensor, constant force can be achieved, which can effectively alleviate the problems of wire breakage and uneven thickness.

[0113] In another embodiment, see Figure 6 The present invention provides an ink direct writing device with integrated high-precision force feedback, which mainly includes: a three-axis motion platform, an extrusion mechanism mounted thereon, and a control system.

[0114] The three-axis motion platform includes an X-axis assembly (14), a Y-axis assembly (15), and a Z-axis assembly (12). Each axis is driven by a stepper motor through a coupling, lead screw, slide rail, and other transmission components, enabling the extrusion mechanism to perform high-precision trajectory movements in three-dimensional space under the command of the control system.

[0115] Reference Figure 1 The extrusion mechanism is fixed on the slider of the Z-axis assembly and mainly includes: an injector (2, 3, 4), a lead screw actuator (9) and a force sensor (1).

[0116] The syringe is a standard syringe, including a syringe (such as 3ml, 5ml, 10ml, etc.) (3) for containing printing ink and a push rod (2) that can slide inside the syringe; the front end of the syringe can be connected to bayonet-type 1 / 4 stainless steel needles (4) with different inner diameters, and different inner diameters can be changed according to actual printing needs.

[0117] The lead screw actuator 9 is an electric actuator used to generate thrust.

[0118] The assembly relationship is as follows:

[0119] The lead screw actuator, force sensor, and syringe plunger are connected in series coaxially along the direction of the thrust. Specifically, one end of the force sensor is connected to the linear slider (11) of the lead screw actuator via a fixing member, and the other end is fixedly connected to the tail of the syringe plunger.

[0120] For example, the force sensor is preferably a high-precision tension / compression sensor or a strain gauge force sensor, which can accurately measure the actual thrust F_actual applied to the push rod by the lead screw actuator.

[0121] Reference Figure 2 Figure 7 Before printing begins, the operator sets a target thrust value F_set in the control system through the human-machine interface.

[0122] Once printing begins, the control system, based on path planning files such as G-codes, controls the motors of the three-axis motion platform to move the extrusion mechanism along a preset trajectory. Simultaneously, it sends an initial drive signal to the drive motor of the lead screw actuator, causing it to push the push rod to extrude ink.

[0123] During the extrusion process, the force sensor feeds back the measured actual thrust F_actual to the control system in real time as an electrical signal (such as a voltage signal).

[0124] Closed-loop control algorithms (such as PID controllers) compare F_actual with a preset F_set to obtain the error e = F_set - F_actual. The controller adjusts the output to the drive motor in real time (e.g., increases or decreases the frequency of the drive pulse) based on the magnitude and sign of the error e, thereby changing the thrust of the lead screw actuator so that F_actual is quickly adjusted to be equal to F_set.

[0125] For example, when an increase in ink viscosity is detected, causing F_actual to rise and exceed F_set, the control system immediately reduces the motor speed, lowering the thrust to the set value. Conversely, when nozzle patency improves or ink thins, causing F_actual to decrease, the system increases the motor output to maintain a constant thrust. This process is continuous and high-frequency, ensuring that the extrusion thrust remains stable near the target value throughout the printing process.

[0126] The present invention also provides a constant force ink direct writing printing method based on the above-mentioned device, comprising the following steps:

[0127] a) Set a target extrusion thrust value in the control system;

[0128] b) Control the three-axis motion platform to make the nozzle of the extrusion mechanism move along a predetermined three-dimensional trajectory;

[0129] c) While moving, the electric actuator of the extrusion mechanism is driven to extrude ink, and the actual thrust applied to the syringe plunger is continuously measured by a force sensor;

[0130] d) Compare the measured actual thrust with the target thrust value set in step a) in real time;

[0131] e) Based on the comparison results, the operation of the electric actuator is dynamically adjusted to minimize the error between the actual thrust and the target thrust value, thereby achieving constant force printing.

[0132] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An ink direct writing device integrated with high-precision force feedback, characterized in that, The utility model relates to a three-axis motion platform for driving an extrusion mechanism to move along a predetermined trajectory in three-dimensional space, an extrusion mechanism fixed on the Z-axis of the three-axis motion platform, including a syringe, an electric actuator and a force sensor, a control system electrically connected to the three-axis motion platform, the electric actuator and the force sensor, wherein the force sensor is coaxially connected in series between the output end of the electric actuator and the push rod of the syringe for real-time measurement of the actual extrusion force applied to the push rod. Preferably, the force sensor is a tension and compression force sensor or a strain gauge force sensor. The electric actuator is a lead screw actuator including an integrated motor and a lead screw. One end of the force sensor is rigidly connected to the linear slider of the electric actuator through a fixing member, and the other end is rigidly connected to the tail of the push rod of the syringe. The control system adopts a PID control algorithm for closed-loop feedback control, which dynamically adjusts the actual force by adjusting the motor speed of the electric actuator.

2. The ink direct writing device integrated with high precision force feedback according to claim 1, characterized in that, The control system includes:

3. The ink direct writing device integrated with high precision force feedback according to claim 1, wherein, a main control unit for arithmetic processing and control instruction generation, 4. The ink direct writing device integrated with high precision force feedback according to claim 1, wherein, a force signal acquisition module for acquiring analog or digital signals output by the high-precision force sensor, 5. The ink direct writing device integrated with high precision force feedback according to claim 1, wherein, a motion control module for controlling the motor drive of the three-axis motion platform, 6. The ink direct writing device integrated with high precision force feedback according to claim 1, wherein, an extrusion control module for independently controlling the motor drive of the electric actuator. The method includes the following steps: S1: setting a target extrusion force value in the control system; S2: controlling the three-axis motion platform to move the printing needle of the extrusion mechanism along a predetermined three-dimensional trajectory; S3: driving the electric actuator to push the push rod to extrude ink, while continuously measuring the actual force applied to the push rod by the high-precision force sensor; 7. A constant force ink direct writing printing method based on an integrated high-precision force feedback ink direct writing device, characterized in that, S4: comparing the measured actual force with the target extrusion force value in real time to obtain a force error; S5: dynamically adjusting the operating parameters of the electric actuator according to the force error through a closed-loop feedback control algorithm to minimize the error between the actual force and the target extrusion force value, thereby achieving constant force extrusion printing. The closed-loop feedback control algorithm is a PID control algorithm that outputs a control quantity by calculating a proportional term, an integral term and a differential term. The control quantity is mapped to the motor pulse frequency of the electric actuator, and the motor speed is changed by adjusting the pulse frequency to adjust the force. ​ ​ ​ 8. The constant force ink direct write printing method of claim 7, wherein, ​

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