Control method and system of servo driver integrated with programmable logic controller

Abstract

The invention relates to the technical field of motion control, in particular to a control method and system of a servo driver integrated with a programmable logic controller, the working mode of the driver is set as a full closed-loop pressure mode, and a module instruction function is started; configuring functions of a digital quantity input port; receiving a trigger signal input through the user-defined press-fitting instruction trigger port; executing a preset custom press-fitting process; and in the pressure control mode, pressure closed-loop control is executed. The PLC logic processing module, the multi-loop control algorithm and the state machine mechanism are integrated in the driver, the whole-process autonomous control from zero returning, inching and positioning to the multi-section press fitting process is achieved, an external PLC does not need to be relied on, and meanwhile high precision, high response and high safety are ensured.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of motion control, in particular to a control method and system of a servo driver integrated with a programmable logic controller. BACKGROUND

[0002] In a conventional automatic press-fit system, an independent PLC is usually used as the main control unit to control the servo driver through analog quantity or bus, and to realize motion and pressure control in cooperation with external displacement sensors (such as grating rulers) and pressure sensors. This architecture has problems such as complex system, high cost, response lag, poor coordination between control loops, etc. Especially in the case of high-precision and high-response-speed pressure control, the control cycle and communication delay of the external PLC become the performance bottleneck, making it difficult to realize close coupling and fast dynamic switching of the position and pressure loops. Most of the servo drivers in the prior art focus on pure position or pure speed control, and even if torque (current) control is supported, complex host computer programming is usually required to realize pressure holding and other processes. For complex processes such as "first move to position, then hold pressure to position" or "first hold pressure, then slight displacement", the configuration is complicated and lacks an integrated solution. Therefore, there is an urgent need for a driver and method that integrates intelligent control logic, simplifies external wiring and programming, and can realize high-speed and high-precision full-closed-loop pressure servo control. SUMMARY

[0003] The present application provides a control method and system of a servo driver integrated with a programmable logic controller to solve the problems in the prior art. By integrating a PLC logic processing module, a multi-loop control algorithm, and a state machine mechanism inside the driver, full-process autonomous control from zero return, jogging, positioning to multi-segment press-fit processes is realized without relying on an external PLC, while ensuring high precision, high response, and high safety.

[0004] To solve the above technical problems, the present application adopts the following technical solutions: The present application provides a control method of a servo driver integrated with a programmable logic controller, which comprises the following steps: Step S1, set the working mode of the driver to full-closed-loop pressure mode and enable the module instruction function; Step S2, configure the function of the digital input port, and assign at least one port as a custom press-fit instruction trigger port; Step S3, receive the trigger signal input through the custom press-fit instruction trigger port; Step S4, execute the preset custom press-fit process, which includes N process segments executed in sequence, where N is an integer greater than or equal to 1; each process segment is independently configured as a position control mode or a pressure control mode; Step S5, in the pressure control mode, a pressure closed-loop control is performed, specifically: based on the error between the target pressure and the feedback pressure from the pressure sensor, a position correction amount is calculated by a pressure loop controller; the position correction amount is input as a position instruction to a position loop controller, driving the servo motor to move to adjust the pressure.

[0005] In step S4, configuring each process section includes: independently setting control mode parameters, target value parameters and speed parameters for each process section; wherein the control mode parameters are used to select absolute position mode, relative position mode, absolute pressure mode or relative pressure mode.

[0006] In step S5, the pressure closed-loop control has three algorithm modes, which are switched by setting the PID factor parameters of the pressure loop controller, including: Mode one: position following mode, the output of the pressure loop controller is a position correction amount instruction; Mode two: speed following mode, the output of the pressure loop controller is a speed instruction; Mode three: model feedforward mode, based on a preset material stiffness coefficient and a target pressure, a feedforward position amount is calculated, and combined with the fine-tuning output of the pressure loop controller, together as a position instruction.

[0007] In the model feedforward mode, the material stiffness coefficient is automatically obtained by the frequency response test function of the driver and filled into the corresponding parameter.

[0008] Before executing the pressure control section of the self-defined press fitting process, it further includes a pressure exploration step: moving at a preset exploration speed and continuously monitoring the pressure; if the pressure reaches the initial contact pressure threshold within the preset exploration distance and is maintained, it is determined that the contact is successful, the current position is recorded as a pressure holding reference point and enters the pressure closed-loop control stage; otherwise, it is determined that the contact is not successful and the process is stopped.

[0009] In step S5, the position correction amount is limited within a pressure holding window defined by a preset compensation lower limit and a compensation upper limit.

[0010] The control method further includes a safety protection step, which at least includes one of the following: When the emergency stop is triggered, all movements are immediately stopped, and after resetting, the zero return operation needs to be re-executed; When the zero return operation is not completed, if the press fitting instruction is triggered, an error is reported and execution is prohibited; When the actual pressure exceeds a preset pressure abnormal threshold or a highest pressure protection threshold, an alarm or stop is triggered.

[0011] The application also provides a control system of a control method of a servo driver based on the integrated programmable logic controller, which comprises: a servo driver body with an integrated programmable logic controller; a servo motor electrically connected to the servo driver body; a position feedback device for detecting the actual position of the servo motor and connected to the feedback interface of the servo driver body to form a full-closed loop position loop; a pressure sensor for detecting real-time pressure and with an analog output end connected to the analog input interface of the servo driver body; a plurality of digital input interfaces for receiving external instruction signals, at least one of which is configured to trigger a custom press fitting process; The servo driver body is configured to: work in a full-closed loop pressure mode; execute a press fitting process composed of a plurality of process segments with independently configurable control modes in response to a custom press fitting instruction triggered through the digital input interface; In the pressure control stage, the servo motor is driven for accurate pressure control through a nested position-pressure double loop control structure based on the feedback of the pressure sensor.

[0012] The position feedback device is an external grating scale of the servo motor and the mechanical transmission mechanism.

[0013] The digital input interface is further configured with enable, reset, zero reset trigger, positive / negative limit, emergency stop and light curtain pause function ports, and the positive / negative limit port is connected to a hardware limit switch.

[0014] The application has the following beneficial effects: The application integrates a PLC logic processing module, a multi-loop control algorithm and a state machine mechanism in the driver to realize full-process autonomous control from zero reset, jogging, positioning to multi-segment press fitting process without relying on an external PLC, while ensuring high precision, high response and high safety. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The application provides a flowchart of the control method of the servo driver with an integrated programmable logic controller.

[0016] Figure 2 The application provides a control logic block diagram of the position following mode.

[0017] Figure 3 The application provides a control logic block diagram of the speed following mode.

[0018] Figure 4The control logic block diagram of the model feedforward mode of the application. DETAILED DESCRIPTION

[0019] For the convenience of those skilled in the art, the application will be further described below in conjunction with the embodiments and the accompanying drawings, and the content mentioned in the embodiments is not a limitation on the application. The application will be described in detail below in conjunction with the accompanying drawings.

[0020] Embodiment one In the embodiment one of the application, the control method of the servo driver integrated with the programmable logic controller comprises the following steps: Step S1, setting the working mode of the driver to full-closed-loop pressure mode, and enabling the module instruction function; Step S2, configuring the function of the digital input port, and assigning at least one port as a self-defined press fitting instruction trigger port; Step S3, receiving the trigger signal input through the self-defined press fitting instruction trigger port; Step S4, executing the preset self-defined press fitting process, the self-defined press fitting process comprising N process segments executed in sequence, wherein N is an integer greater than or equal to 1; each process segment is independently configured as a position control mode or a pressure control mode; Step S5, in the pressure control mode, executing pressure closed-loop control, specifically: based on the error between the target pressure and the feedback pressure from the pressure sensor, calculating the position correction amount through the pressure loop controller; inputting the position correction amount as the position instruction to the position loop controller, and driving the servo motor to move to adjust the pressure.

[0021] Specifically, the application sets the servo driver to full-closed-loop pressure mode, and enables the module instruction function, so that it has the ability to execute complex press fitting processes, receives external trigger signals through the digital input port, starts the preset multi-segment self-defined press fitting process, each segment can independently select position or pressure control mode, and adopts "pressure-position" double closed-loop structure in the pressure control segment, that is, the pressure loop controller calculates the position correction amount based on the pressure error, as the instruction input of the position loop, so as to realize high-precision pressure regulation; realizes high flexibility and automation of the press fitting process, supports complex processes of multi-stage and mixed control mode; through the nested double closed-loop structure, the response speed is guaranteed while the pressure control precision is improved, and it is suitable for precise assembly scenes (such as bearing press fitting, motor rotor assembly, etc.) which have strict requirements on press fitting force and displacement.

[0022] The application realizes the full-process autonomous control from zero return, jogging, positioning to multi-segment press fitting process by integrating the PLC logic processing module, multi-loop control algorithm and state machine mechanism in the driver, without relying on external PLC, while ensuring high precision, high response and high safety.

[0023] In the step S4, the configuration of each process section includes: setting control mode parameters, target value parameters and speed parameters for each process section independently; wherein the control mode parameters are used to select absolute position mode, relative position mode, absolute pressure mode or relative pressure mode. Specifically, under this setting, each process section can be independently configured with control mode (absolute / relative position, absolute / relative pressure), target value (position or pressure set value) and speed parameters, so that the press assembly process can be flexibly arranged according to actual process requirements.

[0024] The parameter configuration process in the embodiment of the application includes: Stage one: basic setting 1. Hardware wiring: Connect the main power supply (RST), motor (UVW) and encoder (CN2).

[0025] Must be connected: external grating ruler (OA+ / OA-, etc.), pressure sensor (AI1 / AI2), DI signal (enable, origin, limit, etc.).

[0026] Key: Ensure that all shielded wires are grounded, and that strong and weak electric cables are separated.

[0027] 2. Power on and basic parameters: Power on, set the driver address and communication parameters (if necessary).

[0028] Run Fn000 (parameter initialization) and then Fn002 (motor parameter self-learning).

[0029] Set the basic mechanical parameters: P15.10 = lead of screw rod (unit: 0.001mm) / / for example, 10mm lead, set to 10000 P15.12 = reduction ratio (unit: 0.01) / / for example, 10:1, set to 10.00 P15.08 = total mechanical stroke (unit: 0.001mm).

[0030] 3. Switch to special mode: P02.01 = 7 / / full closed-loop pressure mode; P15.06 = 1 / / enable module instruction function.

[0031] After the driver is powered on, parameter initialization (Fn000) and motor parameter self-learning (Fn002) are performed. Mechanical parameters are set: lead screw pitch (P15.10), reduction ratio (P15.12), and total mechanical stroke (P15.08). Subsequently, the working mode is switched to the dedicated full-closed-loop pressure mode: P02.01=7 is set, and the module instruction function P15.06=1 is enabled.

[0032] Phase two: sensor calibration and zeroing: 1. Pressure sensor calibration: `P15.02 = 1` (pressure source is AI1) or `2` (AI2).

[0033] `P15.04 = pressure range` (unit: 0.001kN).

[0034] Zero adjustment: The pressure head is suspended, and `P06.68` (AI zero drift) is adjusted so that `P15.82` (real-time pressure) = 0.

[0035] Gain adjustment: A known standard pressure is applied, and `P06.66` (AI amplification factor) is adjusted so that `P15.82` displays the correct value.

[0036] 2. Zero parameter setting and execution: Configure a DI port as `INFn.52` (trigger zeroing).

[0037] DI10 port is fixed as the origin signal input, and the origin sensor is connected.

[0038] Set the zeroing parameters: P18.80 = 2 / / Reverse speed to find zero point (commonly used) P18.82 = zeroing speed P18.86 = zero point offset Trigger `INFn.52`, and observe the motor zeroing until `OutFn.68` output is valid and `P17.95 BIT0` becomes 1. Zero and range calibration of the pressure sensor: Adjust P06.68 (AI zero drift) to make the zero point accurate, and adjust P06.66 (AI amplification factor) to make the displayed value consistent with the standard pressure. Configure a DI as the zeroing trigger (INFn.52), set the zeroing parameters (e.g., P18.80=2, reverse zero point), and perform the zeroing operation until completion to establish the absolute position coordinate system.

[0039] Phase three: instruction function allocation and basic test 1. DI / DO function distribution (Parameter group `P06.xx`): `P06.01` = `INFn.01` (enable) `P06.02` = `INFn.02` (reset) `P06.03` ~ `P06.08`: distribute as needed, for example, to `INFn.90 / 91` (jog), `INFn.49` (position command), `INFn.51` (hold command), or `INFn.54` (customized press).

[0040] `P06.09` = `INFn.52` (zero reset) / / If not previously assigned.

[0041] Note: `INFn.43 / 44` (forward / reverse limit) must be assigned and connected, and the hardware limit protection takes effect when `P17.98 BIT3=0`.

[0042] 2. Module commissioning (recommended in order): Step A: Jog (`INFn.90 / 91`): Confirm motor direction and smooth mechanical operation. Configure `P16.47` (jog speed).

[0043] Step B: Speed command (`INFn.47`): Test basic motion performance. Configure `P18.02` (speed).

[0044] Step C: Position command (`INFn.49`): Test positioning accuracy. Configure `P18.21` (segment number), `P18.22 / 24` (first segment position / speed).

[0045] Step D: Hold command (`INFn.51`): Core test.

[0046] Set `P18.41=1` (only pressure detection + hold).

[0047] Set `P18.50` (initial pressure value, e.g., 0.2KN), `P18.53` (target pressure value, e.g., 5KN).

[0048] Set `P18.44` (detection speed, preferably slow), `P18.64` (maximum compensation speed).

[0049] Trigger operation, observe position-pressure waveform with software, and adjust PID parameters (`P18.61~63`).‌ The DI functions in P06.01~P06.09 parameter group must include enable (INFn.01), reset (INFn.02), forward / reverse limit (INFn.43 / 44) and process instructions planned to use, such as custom press (INFn.54). Then test the basic module functions in sequence, such as jog, speed run, single segment positioning, etc. to ensure the machine is running properly.

[0050] Stage Four: Advanced Process Programming and Pressure Ring Commissioning Programming the "Custom Press" process: `P13.02 = N` (Set total segment number, e.g. 4 segments).

[0051] Segment configuration example (a typical 4-segment press): Segment 1 (Fast Down): `P19.01=0` (Absolute position), `P19.02=High Speed`, `P13.10=Fast Down Position`.

[0052] Segment 2 (Slow Approach): `P19.04=2` (Relative position), `P19.05=Low Speed`, `P13.15=Approach Distance`.

[0053] Segment 3 (Pressure Probe + Ramp Up): `P19.07=1` (Absolute pressure), `P19.08=Low Speed`, `P13.20=Transition Pressure Value`, `P13.24=0` (No Hold Pressure).

[0054] Segment 4 (Final Hold Pressure): `P19.10=1` (Absolute pressure), `P19.11=Lower Speed`, `P13.25=Final Target Pressure`, `P13.29=Hold Pressure Time (ms)`.

[0055] Trigger and Monitoring: Trigger `INFn.54`, monitor current segment via `P13.12`, monitor status via `OutFn.85~89`.

[0056] This stage is the core of implementing complex processes. Define the total number of segments by setting P13.02, e.g. set to 4 segments, then configure each segment, e.g.: Segment 1 (Fast Down): Set control mode (P19.01) to absolute position mode, set target position (P13.10) and high speed (P19.02).

[0057] Segment 2 (Slow Approach): Set control mode (P19.04) to relative position mode, set approach distance (P13.15) and low speed (P19.05).

[0058] Third segment (pressure exploration) : Control mode (P19.07) is set to absolute pressure mode, set transition pressure target value (P13.20) and low speed (P19.08). This stage will start the "pressure exploration" logic: the system moves at low speed and monitors the pressure, once the preset initial contact pressure (P18.50) is reached and maintained, it is determined that "contact is successful" and enters the pressure closed loop.

[0059] Fourth segment (final pressure holding) : Control mode (P19.10) is set to absolute pressure mode, set final target pressure (P13.25) and lower speed (P19.11), and set pressure holding time (P13.29).

[0060] After the configuration is completed, the DI signal assigned to INFn.54 is triggered, and the driver starts to execute the complete process arranged.

[0061] In the pressure control segment, the system will work according to the selected algorithm. Take the most typical position driven mode (P17.96=0) as an example, its working principle: the position correction amount calculated by the outer pressure ring PID (P18.61~63) according to the error is sent to the inner position ring for execution. At the same time, the system has a "pressure holding window" (P18.66 / 68) to limit the compensation range. In order to pursue the ultimate performance, the user can first obtain the system stiffness through the frequency response test function, and then switch to the model feedforward mode (P17.96=500), fill in the stiffness value in P16.34, and use feedforward to greatly improve the response speed, at this time the pressure ring PID only plays a fine tuning role.

[0062] Stage five: final confirmation of safety and protection parameters 1. Gain and performance optimization: Use the frequency response test function (`INFn.94`) in Chapter 9 and Section 4.11 to obtain the system lag time and material stiffness (`P16.74`).

[0063] Fill in the stiffness value in `P16.34`, and try to set `P17.96` to `500` (model feedforward mode) to greatly improve the pressure response speed.

[0064] 2. Final review of protection parameters: Confirm that `P16.40` (the highest protection threshold of the press) is set reasonably.

[0065] Confirm that each bit in `P17.98` (such as light curtain processing method, inching limit) meets the safety specifications.

[0066] Confirm that the software limit `P19.51 / P19.53` has been set.

[0067] Make sure all safety parameters are properly set, including pressure protection thresholds at all levels (P16.36 / 38 / 40), software limits (P19.51 / 53), and safety function options (P17.98).

[0068] Implementation details of logical control in the embodiments of the present application: 1. Overall framework of control logic: Working mode: Set to "full closed-loop pressure mode" by `P02.01 = 7`. In this mode, the driver supports switching or compound control between position closed-loop (using a grating ruler) and pressure closed-loop (using a pressure sensor).

[0069] Instruction trigger: All complex actions are executed through the "instruction module". The user triggers it by sending a rising edge or high-level signal to the corresponding input function bit.

[0070] Trigger source: It can be a physical DI terminal (such as a button) or a virtual DI bit written by Modbus communication.

[0071] Modularity: Each module (such as speed, position, pressure holding, custom pressure loading) is an independent "small program". Any new triggered instruction can immediately interrupt the currently running instruction, responding quickly.

[0072] Core logic unit: `Custom pressure loading instruction (INFn.54)` is the highest level logic unit. It allows the user to arrange a "process recipe" of up to 16 steps, each step can be independently selected as "absolute / relative position" or "absolute / relative pressure" mode, and set speed, target value, waiting / pressure holding time.

[0073] 2. Details of pressure closed-loop control logic: This is the core value of the driver, and its logic is much more complex than simple position control.

[0074] Control loop structure: In the pressure control phase, the system forms a "position loop-pressure loop" nested structure.

[0075] ① Outer ring - pressure loop: The PID controller (`P18.61, P18.62, P18.63`) calculates the position correction amount needed to compensate for the error between the target pressure and the feedback pressure.

[0076] ② Inner ring - position loop: Take the above position correction amount as the new position instruction, and move the motor to change the pressure.

[0077] ③ Limit and protection: Position compensation is limited between `P18.66` (lower compensation limit) and `P18.68` (upper compensation limit), forming a "hold pressure window" to prevent over-adjustment. At the same time, there is a pressure over-limit alarm (`P16.40` and others).

[0078] "Pressure exploration" logic: Before entering pressure PID control, the system will advance a certain distance (`P18.42`) at a lower speed (`P18.44`). During this period, the pressure is continuously monitored.

[0079] If the pressure reaches the initial value (`P18.50`) and remains for a certain period of time (`P18.52`), it is determined that "contact is successful", the flag bit `OutFn.65` is set, and the system records the position at this moment as the hold pressure reference point, and then enters the PID hold pressure phase.

[0080] If the initial pressure is not reached after the detection distance is completed, it is determined that "contact is not successful", the flag bit `OutFn.64` is set, and the process stops.

[0081] Three pressure algorithm selection (`P17.96`): 0 - Position following: PID output = position correction. Highest steady-state accuracy, suitable for hard materials or final hold pressure.

[0082] 500 - Model feedforward: Pre-calculate position based on material stiffness (`P16.74`). Fastest response, dependent on accurate model.

[0083] 1000 - Velocity following: PID output = velocity command. Smooth dynamic process, suitable for soft materials or contact processes, but prone to overshooting.

[0084] 3、Safety and protection logic: The system has designed multiple levels of safety logic to ensure the safety of the press and the product.

[0085] Interlock logic: `INFn.13` (emergency stop): Triggered, immediately stop, must be reset to zero before continuing operation.

[0086] `INFn.21` (light curtain pause): Triggered, pause, after resuming, it may re-execute from the beginning of this process, depending on the configuration of `P17.98`.

[0087] When not reset to zero (`P17.95 BIT0=0`), triggering the press fitting command will report an error `Er.205`.

[0088] Over-limit protection: Software limit: Effective after reset, alarm if position exceeds `P19.51 / P19.53`.

[0089] Pressure mode displacement protection: in the pressure control section, if the displacement exceeds the range of `P18.66 / P18.68`, the section can be paused or skipped.

[0090] Pressure overrun protection: in three stages: ① `P16.36`: pressure abnormal threshold in position mode.

[0091] ② `P16.38`: pressure abnormal threshold in pressure mode.

[0092] ③ `P16.40`: maximum pressure threshold of the entire machine (final barrier).

[0093] In the embodiment of the application, the pressure closed-loop control has three algorithm modes in step S5, which are switched by setting the PID factor parameters of the pressure loop controller, including: Mode one: position following mode, the output of the pressure loop controller is a position correction command; Mode two: speed following mode, the output of the pressure loop controller is a speed command; Mode three: model feedforward mode, based on the preset material stiffness coefficient and target pressure, the feedforward position is calculated in advance through a physical model (F=K·ΔX), and the fine-tuning output of the pressure loop controller is combined to serve as a position command.

[0094] Specifically, under the above settings, the control strategy is intelligently switched according to different working conditions, considering response speed, stability and anti-interference ability; especially in the model feedforward mode, the pressure build-up time is greatly shortened, and the pressure assembly efficiency and consistency are improved.

[0095] In the embodiment of the application, the position following mode (`P17.96 = 0`) is the most classic, most stable, and default pressure control algorithm. The core idea is to "regulate pressure with displacement", which completely converts the "pressure control" problem into a high-precision "position fine-tuning" problem. The PID output of the pressure loop is not a force or a speed, but a position correction amount that needs to be compensated, and the control logic diagram is as shown in Figure 2 . Pressure loop: as the outer loop, according to the error between the target pressure and the feedback pressure, the PID operation outputs a `Δ position` command.

[0096] Position loop: as the inner loop, it accepts this `Δ position` command to drive the motor to move the corresponding distance accurately, thereby changing the extrusion amount and ultimately affecting the pressure.

[0097] Key to implementation: The compensation amount is limited within the compensation window (lower limit `P18.66`, upper limit `P18.68`) to prevent infinite accumulation.

[0098] The tuning of the pressure loop PID parameters (`P18.61~63`) is crucial. Excessive integral action (`I`) will cause the system to oscillate at low frequencies near the target point.

[0099] Advantages: Extremely high steady-state accuracy: Due to the high accuracy of the position loop itself, pressure fluctuations are minimal during the final pressure holding stage. Clear structure and good robustness: Low dependence on system models (such as mechanical stiffness) and stronger adaptability. No steady-state error: Integral action can effectively eliminate steady-state pressure errors.

[0100] In this embodiment, the speed-driven mode (`P17.96 = 1000`) is a more intuitive control method with better dynamic performance. Its core idea is "controlling pressure based on trends." The system focuses on the changing trend of pressure. The output of the pressure loop PID directly provides a speed command, controlling how quickly the motor "approaches" or "moves away" from the target pressure. The control logic block diagram is as follows: Figure 3 As shown: Pressure loop: The output is a speed command (`V_cmd`). "If the pressure is too high, it will move backward; if the pressure is too low, it will move forward," and the forward / backward speed is proportional to the pressure error.

[0101] Speed ​​Loop: As the inner loop of execution, it quickly tracks this speed command.

[0102] Advantages: Fast dynamic response and natural process: Pressure changes directly correspond to speed commands, resulting in a more direct response, especially smoother during the contact and pressurization phases. Friendly to soft materials and long-stroke compression: Allows for gentler control of the compression process, reducing impact.

[0103] In this embodiment, the model feedforward mode (`P17.96 = 500`) is the predictive control algorithm with the highest theoretical performance limit. Its core idea is "replacing reaction with calculation." The system no longer passively waits for errors to occur before adjusting; instead, it actively calculates the theoretical displacement required to reach the target pressure based on the physical model (Hooke's Law F = KΔX) and directly provides it as a feedforward command. The control logic block diagram is as follows: Figure 4 As shown: Feedforward path: The core is to use the parameter `P16.34` (material elastic modulus grade coefficient) as stiffness `K`, and instantly calculate the required displacement change `ΔX = F_target / K` based on the target pressure `F_target`, and superimpose it on the position command, which provides the main and rapid output force.

[0104] Feedback path: The pressure loop PID still exists, but its role is weakened to a trimmer, mainly used to compensate for model errors, friction, and other unmodeled factors.

[0105] Advantages: Theoretical response is the fastest, almost no lag: the feedforward instruction is calculated instantaneously, skipping the error accumulation process of the PID; the risk of overshoot is low: based on model-based accurate calculation, not relying on integral "hard top", more stable when approaching the target.

[0106] In the model feedforward mode in the embodiments of the present application, the material stiffness coefficient is automatically obtained by the frequency response test function of the driver and filled into the corresponding parameter. Specifically, under the above setting, the stiffness characteristics of the material to be pressed are automatically identified before pressing by using the built-in frequency response test function of the driver, and the parameter is used for feedforward model calculation; manual calibration error is avoided, self-adaptive pressing is realized; the feedforward control precision is improved, especially suitable for material batch change or unknown stiffness scene, and the system robustness is enhanced.

[0107] In the embodiments of the present application, before the pressure control section of the self-defined pressing process is executed, a pressure exploration step is further included: moving at a preset exploration speed and continuously monitoring the pressure; if the pressure reaches the initial contact pressure threshold and remains within the preset exploration distance, it is determined that the contact is successful, the current position is recorded as the pressure holding reference point and enters the pressure closed loop control stage; otherwise, it is determined that the contact is not successful and the process is stopped. Specifically, under the above setting, before the formal pressure control, the workpiece contact point is found by low-speed exploration movement: when the pressure reaches the preset threshold and is stable, the current position is recorded as the pressure holding reference; otherwise, it is determined that the contact is not successful and the process is stopped; effectively prevent the risk of "empty pressing" or "overshoot", ensure that each pressing starts from the real contact point, and improve the process repeatability; at the same time, it has error prevention ability, avoiding equipment damage or product scrap.

[0108] In the embodiments of the present application, in the step S5, the position correction amount is limited within the pressure holding window defined by the preset compensation lower limit and the compensation upper limit. Specifically, under the above setting, the upper and lower limit constraints (pressure holding window) are applied to the position correction amount of the pressure loop output, preventing the motor from overcompensating due to pressure fluctuations and causing oscillation or overtravel; enhance system stability, avoid mechanical impact or loss of control due to control overshoot; limit the actuator action range while ensuring pressure accuracy, improve safety.

[0109] In the embodiments of the present application, the control method further includes a safety protection step, which at least includes one of the following: When the emergency stop is triggered, all movements are immediately stopped, and after reset, the zero return operation needs to be performed again; When the zero return operation is not completed, if the pressing instruction is triggered, an error is reported and execution is prohibited; When the actual pressure exceeds the preset pressure abnormal threshold or the maximum pressure protection threshold, an alarm is triggered or stopped.

[0110] Specifically, under the above settings, multiple safety logics are integrated: forced zero reset after emergency stop, no zero reset to prohibit press fitting, pressure overrun alarm / stop, etc., forming a complete safety protection chain; effectively preventing personal injury and equipment failure; ensuring reliable shutdown of the system in abnormal state and preventing misoperation restart, improving overall reliability.

[0111] Embodiment two

[0112] In the embodiment two of the application, a control system of a control method of a servo driver based on the integrated programmable logic controller is provided, which comprises: a servo driver main body, which is internally provided with a programmable logic controller; a servo motor, which is electrically connected with the servo driver main body; a position feedback device, which is used for detecting the actual position of the servo motor and is connected with a feedback interface of the servo driver main body to form a full-closed loop position loop; a pressure sensor, which is used for detecting real-time pressure and has an analog output end connected with an analog input interface of the servo driver main body; a plurality of digital input interfaces, which are used for receiving external instruction signals, and at least one of which is configured to trigger a self-defined press fitting process; The servo driver main body is configured to: work in a full-closed loop pressure mode; execute a press fitting process composed of a plurality of process segments with independently configurable control modes in response to a self-defined press fitting instruction triggered through the digital input interface; In the pressure control stage, the servo motor is driven to perform accurate pressure control through a nested position-pressure double-loop control structure based on the feedback of the pressure sensor.

[0113] In the embodiment two of the application, the position feedback device is an external grating scale of the servo motor and the mechanical transmission mechanism. Specifically, under the above settings, the grating scale installed at the mechanical end is used as a position feedback source to directly detect the actual position of the load end, thereby forming a true full-closed loop control system, overcoming the problems that the motor encoder cannot reflect the mechanical deformation, back gap, etc., and significantly improving the press fitting end position accuracy, which is suitable for high-rigidity or long-stroke press fitting equipment.

[0114] In the second embodiment of the present application, the digital input interface is further configured with enable, reset, zero reset trigger, positive / negative limit, emergency stop and light curtain pause function ports; and the positive / negative limit ports are connected with hardware limit switches. Specifically, under the above settings, the multiple digital input ports can be flexibly distributed as pressing trigger, enable, reset, zero reset, limit, emergency stop, light curtain pause and other functions, and connected with hardware limit switches; the embodiment of the present application provides complete local I / O control capability, supports seamless integration with peripheral safety devices such as safety light curtains and mechanical limiters; improves the independent operation capability of the system, and is suitable for single-machine automation scenarios without an upper computer.

[0115] The embodiment of the present application deeply integrates PLC logic, motion control and advanced pressure servo algorithm in a single driver, greatly simplifies system design, debugging and maintenance work through the way of "instruction module" and "process recipe", realizes high-precision, high-response and high-reliability full-closed-loop pressure control, and is particularly suitable for industrial application scenarios with strict requirements on process flexibility, control accuracy and production rhythm.

[0116] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Although the present application is disclosed as above with the preferred embodiment, it is not intended to limit the present application. Any skilled person in the art can make some changes or modifications to the above disclosed technical content without departing from the scope of the technical solution of the present application, and any simple modification, equivalent change and modification made to the above embodiment within the scope of the technical solution of the present application are all within the scope of the technical solution of the present application.

Claims

1. A control method for a servo driver integrating a programmable logic controller, characterized in that, Includes the following steps: Step S1: Set the driver's operating mode to full closed-loop pressure mode and enable the module command function; Step S2: Configure the functions of the digital input ports, and assign at least one port as a custom press-fit command trigger port; Step S3: Receive the trigger signal input through the custom pressing instruction trigger port; Step S4: Execute a preset custom pressing process, which includes N process segments executed sequentially, where N is an integer greater than or equal to 1; each process segment is independently configured as a position control mode or a pressure control mode. Step S5: In the pressure control mode, pressure closed-loop control is executed, specifically: based on the error between the target pressure and the feedback pressure from the pressure sensor, the position correction amount is calculated by the pressure loop controller; the position correction amount is input as a position command to the position loop controller to drive the servo motor to move and adjust the pressure.

2. The control method for the servo driver with an integrated programmable logic controller according to claim 1, characterized in that, In step S4, configuring each process segment includes: independently setting control mode parameters, target value parameters, and speed parameters for each process segment; wherein, the control mode parameters are used to select absolute position mode, relative position mode, absolute pressure mode, or relative pressure mode.

3. The control method for the servo driver with an integrated programmable logic controller according to claim 1, characterized in that, In step S5, the pressure closed-loop control has three algorithm modes, which are switched by setting the PID factor parameters of the pressure loop controller. These modes include: Mode 1: Position-driven mode, where the output of the pressure ring controller is a position correction command; Mode 2: Speed-driven mode, where the output of the pressure ring controller is a speed command; Mode 3: Model feedforward mode, which calculates the feedforward position based on the preset material stiffness coefficient and target pressure, and combines it with the fine-tuning output of the pressure ring controller as the position command.

4. The control method for the servo driver with an integrated programmable logic controller according to claim 3, characterized in that, In the model feedforward mode, the material stiffness coefficient is automatically obtained and filled into the corresponding parameters through the frequency response test function of the driver.

5. The control method for a servo driver with an integrated programmable logic controller according to claim 1, characterized in that, Before the pressure control section of the customized press-fitting process is executed, a pressure detection step is also included: moving at a preset detection speed and continuously monitoring the pressure; if the pressure reaches the initial contact pressure threshold within the preset detection distance and is maintained, the contact is determined to be successful, the current position is recorded as the pressure holding reference point and the pressure closed-loop control stage is entered; otherwise, the contact is determined to be unsuccessful and the process is stopped.

6. The control method for the servo driver with an integrated programmable logic controller according to claim 1, characterized in that: In step S5, the position correction amount is limited to the pressure holding window defined by the preset compensation lower limit and compensation upper limit.

7. The control method for the servo driver with an integrated programmable logic controller according to claim 1, characterized in that, The control method further includes a safety protection step, which includes at least one of the following: When an emergency stop is triggered, all movement is immediately stopped, and the zero-return operation must be performed again after resetting. If the zero-return operation is not completed, an error will be reported and execution will be prohibited if a pressing command is triggered. When the actual pressure exceeds the preset pressure abnormality threshold or the maximum pressure protection threshold, an alarm will be triggered or the system will stop.

8. A control system based on a control method for a servo driver with an integrated programmable logic controller as described in any one of claims 1-7, characterized in that, include: The servo drive body has a built-in programmable logic controller. A servo motor is electrically connected to the main body of the servo driver; A position feedback device is used to detect the actual position of the servo motor and is connected to the feedback interface of the servo driver body to form a fully closed-loop position loop. A pressure sensor is used to detect real-time pressure, and its analog output terminal is connected to the analog input interface of the servo drive body. Multiple digital input interfaces are used to receive external command signals, at least one of which is configured to trigger a custom press-fitting process; The servo driver body is configured as follows: It operates in a fully closed-loop pressure mode; In response to a custom pressing command triggered via the digital input interface, a pressing process consisting of multiple process segments with independently configurable control modes is executed. During the pressure control phase, based on the feedback from the pressure sensor, the servo motor is driven to perform precise pressure control through a nested position-pressure dual-loop control structure.

9. The control system according to claim 8, characterized in that: The position feedback device is an external grating ruler mounted on the servo motor and mechanical transmission mechanism.

10. The control system according to claim 8, characterized in that: The digital input interface is also equipped with enable, reset, zero-trigger, forward / reverse limit, emergency stop and light curtain pause function ports; and the forward / reverse limit port is connected to a hardware limit switch.

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