Non-circular gear transmission real-time error compensation and synchronous control system of intermittent paper feeding mechanism

Abstract

The invention discloses a non-circular gear transmission real-time error compensation and synchronous control system of an intermittent paper feeding mechanism. The non-circular gear transmission real-time error compensation and synchronous control system comprises a double non-circular gear transmission assembly, a driving motor, a non-circular gear pitch curve characteristic detection unit, a paper feeding position detection unit, a controller and a servo driver. A motor encoder, a grating code disc and a laser interferometer are used for collecting an active non-circular gear rotation angle position signal, a pitch curve actual rotation angle difference signal and a paper feeding execution mechanism actual displacement signal respectively; the controller calls a theoretical transmission model to calculate a theoretical rotation angle value and a paper feeding theoretical displacement value of the driven non-circular gear, a pitch curve meshing error and a paper feeding displacement error are obtained through comparison, the rotation angle compensation amount is calculated after coupling analysis, a correction motor control signal is generated to drive a servo driver to adjust a driving motor, and error closed-loop compensation is achieved. The system can sense and compensate the transmission dynamic error of the non-circular gear in real time, and the paper feeding position precision and the transmission stability are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of automation production and precision manufacturing, and particularly relates to a real-time error compensation and synchronous control system for a non-circular gear transmission of an intermittent paper feeding mechanism. BACKGROUND

[0002] In the field of automation production and precision manufacturing, an intermittent paper feeding mechanism is a core device for realizing intermittent conveying of paper, film and other flexible materials, and is widely used in printing, packaging, electronic processing and other industries. Its performance directly affects the production efficiency and product quality. In order to meet the high-precision requirements of intermittent motion, double non-circular gear transmission, with its non-uniform transmission characteristics, can flexibly realize specific motion law output through the meshing of a pair of non-circular gear curves, and has become a key transmission component in the intermittent paper feeding mechanism. In actual operation, due to manufacturing and installation errors, material elastic deformation, load fluctuations and other factors, the double non-circular gear transmission is prone to motion errors, resulting in a decrease in paper feeding position accuracy. Therefore, the real-time error compensation and synchronous control system, by dynamically monitoring, analyzing and correcting the errors in the transmission process, and coordinating the synchronization of multi-axis motion, has become an important technical means to improve the overall performance of the intermittent paper feeding mechanism.

[0003] At present, for the transmission control of the intermittent paper feeding mechanism, the existing technology mainly focuses on the optimization design of the geometric parameters of the non-circular gear pair to make its output motion closer to the required intermittent law, and at the same time, mechanical means are used to ensure the smoothness and repeatability of the transmission during the assembly and debugging of the mechanism. Some solutions also introduce sensors and feedback control to monitor the paper feeding position or speed, and make certain degree of synchronization and error correction through conventional motor speed regulation or phase adjustment means.

[0004] In actual application, due to manufacturing tolerances, assembly deviations, material deformation and wear during long-term operation, real-time deviations between actual motion law and ideal design will inevitably occur in the transmission process of the double non-circular gear pair. This deviation will directly affect the timing, position and stability of the paper feeding action, and further affect the processing quality and efficiency of the entire production line. Especially in high-speed or long-time continuous operation conditions, if the real-time transmission error is not compensated effectively, it will cause paper feeding position deviation, unstable stop time and other problems, and even cause equipment failure or product defects. The existing control technology mainly relies on mechanical precision guarantee or simple feedback adjustment in the early stage, and lacks the ability to detect and dynamically compensate the real-time transmission error of the double non-circular gear pair during operation, especially in the case of strict synchronization and coordinated motion between the double non-circular gears. It is difficult to achieve high-precision motion consistency control through traditional methods.

[0005] Therefore, how to construct a set of real-time sensing, analyzing and compensating dynamic error synchronization control scheme for the double non-circular gear transmission system of the intermittent paper feeding mechanism has become a problem to be solved in the industry. SUMMARY

[0006] The present application aims at the deficiencies of the prior art, and provides an intermittent paper feeding mechanism non-circular gear transmission real-time error compensation and synchronization control system to solve the problem that the existing control technology relies on the pre-stage mechanical precision guarantee or simple feedback regulation, and lacks the ability of online detection and dynamic compensation of the transmission error generated by the double non-circular gear pair in the running process.

[0007] The present application provides an intermittent paper feeding mechanism non-circular gear transmission real-time error compensation and synchronization control system, comprising a double non-circular gear transmission assembly, a driving motor, a non-circular gear pitch curve characteristic detection unit, a paper feeding position detection unit, a controller and a servo driver. The double non-circular gear transmission assembly comprises a driving non-circular gear and a driven non-circular gear, the driving non-circular gear is connected with the output shaft of the driving motor, the driven non-circular gear is connected with the paper feeding execution mechanism through a transmission shaft, and the driving non-circular gear and the driven non-circular gear are engaged in transmission. The driving motor is used for driving the driving non-circular gear to rotate, and a motor encoder is built-in, which collects the rotation angle position signal of the driving non-circular gear in real time. The non-circular gear pitch curve characteristic detection unit comprises a first grating code disc fixed on the end face of the driving non-circular gear, a second grating code disc fixed on the end face of the driven non-circular gear, and grating read heads correspondingly arranged with the first grating code disc and the second grating code disc, the grating read heads are electrically connected with the controller through signal lines, and are used for collecting the actual rotation angle difference signal of the driving non-circular gear and the driven non-circular gear in real time. The paper feeding position detection unit comprises a laser interferometer fixed on the end of the movement track of the paper feeding execution mechanism, the detection light path of the laser interferometer is parallel to the displacement direction of the paper feeding execution mechanism, and is used for collecting the actual displacement signal of the paper feeding execution mechanism in real time. The controller is built-in with a non-circular gear theoretical transmission model storage module, the theoretical transmission model storage module pre-stores the pitch curve parameters and the theoretical transmission ratio function of the driving non-circular gear and the driven non-circular gear, the controller is electrically connected with the motor encoder, the grating read head and the laser interferometer through signal lines, and bidirectionally communicates with the servo driver of the driving motor through a control bus. The servo driver is electrically connected with the controller at the input end and electrically connected with the driving motor at the output end, and is used for receiving the control signal and driving the motor to run.

[0008] Further, the real-time error compensation and synchronization control is performed in the following manner: the motor encoder collects the rotation angle position signal of the driving non-circular gear in real time and transmits the rotation angle position signal to the controller; the first grating code disc and the second grating code disc synchronously collect the actual rotation angle difference signal of the pitch curve of the driving non-circular gear and the driven non-circular gear through a grating reader, and transmit the actual rotation angle difference signal of the pitch curve to the controller; the laser interferometer collects the actual displacement signal of the paper feeding actuator in real time, and transmits the actual displacement signal to the controller; the controller calls the built-in non-circular gear theoretical transmission model storage module, calculates the theoretical rotation angle value of the driven non-circular gear and the theoretical displacement value of the paper feeding actuator based on the rotation angle position signal of the driving non-circular gear, and combines the pre-stored pitch curve parameters and the theoretical transmission ratio function; the controller compares the actual rotation angle difference signal of the pitch curve with the theoretical rotation angle difference calculated based on the theoretical rotation angle value of the driven non-circular gear, to obtain the pitch curve meshing error; compares the actual displacement signal of the paper feeding actuator with the theoretical displacement value, to obtain the paper feeding displacement error; based on the periodic meshing characteristics of the non-circular gear pitch curve, the pitch curve meshing error and the paper feeding displacement error are coupled and analyzed, to obtain the rotation angle compensation amount of the driving non-circular gear; the controller superimposes the rotation angle compensation amount to the theoretical rotation angle instruction of the driving non-circular gear, to generate the corrected motor control signal, which is transmitted to the servo driver through the control bus; the servo driver adjusts the output rotation speed and rotation angle of the driving motor according to the corrected motor control signal, to drive the driving non-circular gear to correct the pitch curve meshing phase, and drive the driven non-circular gear to be synchronously adjusted through the double non-circular gear meshing transmission, until the pitch curve meshing error and the paper feeding displacement error are both less than the preset threshold.

[0009] Further, the motor encoder is an encoder with non-circular gear rotation angle correction function, which pre-stores the pitch curve profile characteristic parameters of the driving non-circular gear inside, can dynamically adjust the sampling frequency according to the actual rotation position of the driving non-circular gear, automatically increases the sampling density of the rotation angle position signal in the area where the pitch curve curvature radius change rate is greater than the preset threshold, and keeps the preset sampling density in the area where the pitch curve curvature radius change rate is less than the preset threshold; the grating line patterns of the first grating code disc and the second grating code disc are one-to-one corresponding to the pitch curve shapes of the driving non-circular gear and the driven non-circular gear respectively, the radial spacing of the grating lines changes synchronously with the curvature radius of the corresponding non-circular gear pitch curve, so that the actual rotation angle difference signal of the pitch curve collected by the grating reader directly contains the instantaneous transmission ratio fluctuation information in the meshing process of the non-circular gear; the measurement light path of the laser interferometer is provided with a dynamic sampling trigger module matched with the non-circular gear transmission period, which can increase the collection frequency of the actual displacement signal when the paper feeding execution mechanism is in the non-uniform speed movement stage, and reduce the collection frequency when the paper feeding execution mechanism is in the intermittent pause stage; the pre-stored pitch curve parameters in the non-circular gear theoretical transmission model storage module include the discretized coordinate point set corresponding to the actual pitch curve equation of the driving non-circular gear and the driven non-circular gear, the theoretical transmission ratio function is a transmission ratio curve varying with the rotation angle of the driving non-circular gear calculated according to the pitch curve parameters of the driving non-circular gear and the driven non-circular gear, and the controller determines the current position of the driving non-circular gear in the pitch curve according to the rotation angle position signal of the driving non-circular gear when calculating the theoretical rotation angle value of the driven non-circular gear, and calculates the theoretical rotation angle value of the driven non-circular gear corresponding to the current rotation angle of the driving non-circular gear by querying the pre-stored discretized coordinate point set and the theoretical transmission ratio curve and using the piecewise linear interpolation algorithm.

[0010] Further, the controller divides the whole rotation angle of the driving non-circular gear into a plurality of rotation angle intervals corresponding to the characteristic points of the pitch curve when determining the current position of the driving non-circular gear in the pitch curve, the start point and the end point of each rotation angle interval correspond to the curvature extreme points or inflection points of the pitch curve, the discrete coordinate point set is stored in segments according to the rotation angle intervals, and the density of the coordinate points in each rotation angle interval increases with the increase of the curvature change rate of the pitch curve; when receiving the rotation angle position signal transmitted by the motor encoder, the controller determines the target rotation angle interval to which the rotation angle position signal belongs through the interval matching algorithm, and then determines the current position of the driving non-circular gear in the pitch curve according to the pre-stored discrete coordinate point set of the pitch curve in the target rotation angle interval through the characteristic point comparison, wherein the controller calls the high-precision interpolation submodule for coordinate point matching in the rotation angle interval in which the curvature radius change rate of the pitch curve is greater than a preset threshold, and calls the conventional matching submodule in the interval in which the curvature radius change rate is less than the preset threshold; when querying the pre-stored discrete coordinate point set and the theoretical transmission ratio curve, the controller adopts a chain query structure corresponding to the meshing sequence of the non-circular gears, calls the pitch curve coordinate data of the driving non-circular gear in the current rotation angle interval from the discrete coordinate point set, and synchronously calls the pitch curve coordinate data of the corresponding meshing interval of the driven non-circular gear and the theoretical transmission ratio curve segment, the theoretical transmission ratio curve segment is stored in segments according to the rotation angle interval of the driving non-circular gear, and each segment of the curve contains a transmission ratio correction coefficient corresponding to the curvature change of the pitch curve; when calculating the theoretical rotation angle value of the driven non-circular gear by using the piecewise linear interpolation algorithm, the controller selects two adjacent discrete coordinate points in the target rotation angle interval as the interpolation base points according to the current rotation angle position signal of the driving non-circular gear, wherein the former base point is the nearest pitch curve characteristic point before the current rotation angle position, and the latter base point is the nearest pitch curve characteristic point after the current rotation angle position, then the instantaneous theoretical transmission ratio of the current position is calculated by weighted interpolation according to the theoretical transmission ratio values corresponding to the two base points and the deviation of the current rotation angle from the base point rotation angle, the rotation angle increment of the driving non-circular gear is multiplied by the instantaneous theoretical transmission ratio, and the result is superimposed on the initial theoretical rotation angle value of the driven non-circular gear to obtain the real-time theoretical rotation angle value of the driven non-circular gear, wherein in the interval in which the curvature change rate of the pitch curve is greater than the preset threshold, the weight coefficient of the interpolation calculation dynamically shifts to the side with the greater curvature change rate.

[0011] Furthermore, when performing non-circular gear meshing error coupling analysis, the controller synchronizes the actual pitch curve angle difference signal and the actual displacement signal of the paper feeding actuator according to the rotation angle position of the active non-circular gear on the time axis; it extracts the periodic variation characteristics of the pitch curve meshing error and paper feeding displacement error during one rotation of the active non-circular gear, identifies the main period and harmonic components of the error variation, wherein the main period is consistent with the meshing period of the non-circular gear; based on the closed characteristics of the non-circular gear pitch curve, the pitch curve meshing error and paper feeding displacement error within one meshing cycle are decomposed into a systematic error component related to the pitch curve profile and a random error component related to the meshing clearance and elastic deformation. A compensation algorithm based on the inverse solution of the pitch curve is used for the systematic error component, and an adaptive filtering algorithm is used for the random error component. Finally, the results of the two algorithms are superimposed to obtain the rotation angle compensation amount of the active non-circular gear.

[0012] Furthermore, when the controller synchronizes the actual pitch curve angle difference signal and the actual displacement signal of the paper feeding actuator according to the angular position of the driving non-circular gear, it uses the angular position signal of the driving non-circular gear as the synchronization reference axis. The scale division of this reference axis corresponds one-to-one with the closed cycle of the pitch curve of the driving non-circular gear, with each rotation corresponding to a complete pitch curve cycle. The controller internally sets up an angle-time mapping table, which pre-stores the theoretical timestamps corresponding to different angular positions of the driving non-circular gear. By comparing the acquisition timestamps of the actual pitch curve angle difference signal and the actual displacement signal with the theoretical timestamps in the mapping table, the time synchronization deviation value is calculated. Based on this deviation value, the sampling points of the two signals are dynamically aligned to ensure that the pitch curve meshing error and paper feeding displacement error at the same angular position can be accurately correlated. Specifically, at the major and minor axis ends of the driving non-circular gear pitch curve... The synchronization accuracy of the point position is set higher than that of other positions. When the controller extracts the periodic variation characteristics of the pitch curve meshing error and paper feeding displacement error during one revolution of the active non-circular gear, it adopts a segmented periodic extraction method based on the feature points of the pitch curve to identify the start and end points of the closed period of the active non-circular gear pitch curve. Taking the point with the maximum radius of curvature of the pitch curve as the start point of the period, the whole revolution of rotation is divided into multiple feature segments corresponding to the change of the pitch curve contour. The length of each feature segment is dynamically adjusted according to the rate of change of the radius of curvature of the pitch curve. The feature segments in areas with a large rate of change of curvature are divided more finely. The error signal in each feature segment is analyzed independently to extract the local periodic components in each feature segment. Then, the local periodic components are coupled with the whole revolution main period to finally identify the main period of error change and each harmonic component. Among them, the extraction weight of the main period is tilted towards the feature segments with a large rate of change of pitch curve curvature.

[0013] Further, the controller calls pre-stored active non-circular gear and driven non-circular gear pitch curve profile data when decomposing error components according to the closed characteristic of the non-circular gear pitch curve, calculates the theoretical meshing gap through the pitch curve profile comparison algorithm, and takes the theoretical meshing gap as the basic threshold of the systematic error component; for the pitch curve meshing error, the part of the error value that is consistent with the deviation trend of the pitch curve profile data and has a regular change in amplitude with the angular position is determined as the systematic error component, and the part of the error value that exceeds the range of the theoretical meshing gap and has no obvious change is determined as the random error component; for the paper feeding displacement error, the part of the displacement error that is linearly related to the change of the pitch curve profile is separated as the systematic error component through the establishment of the pitch curve profile-displacement transfer function, and the remaining part is further decomposed into the random error component combined with the output torque fluctuation data of the driving motor, wherein the decomposition process of the systematic error component needs to introduce the pitch curve closed constraint condition, and the integral sum of the systematic error component in one period is zero; the compensation algorithm based on the inverse solution of the pitch curve realizes the compensation process for the systematic error component by calling the inverse solution model of the non-circular gear pitch curve, which can inversely calculate the profile parameters of the active non-circular gear pitch curve that need to be corrected according to the currently identified systematic error component; the controller calculates the compensation coefficient of the active non-circular gear at each angular position according to the correction amount of the pitch curve profile parameter, which increases with the increase of the pitch curve curvature radius and decreases with the decrease of the pitch curve curvature radius; the adaptive filtering algorithm adopts a variable step-size filtering strategy matched with the non-circular gear meshing frequency for the compensation process of the random error component, the size of the filtering window is dynamically adjusted according to the angular position of the current active non-circular gear, narrow window filtering is used in the area where the pitch curve meshing frequency is higher than the preset threshold, and wide window filtering is used in the area where the meshing frequency is lower than the preset threshold, while the filtering coefficient is set to be positively correlated with the real-time meshing gap of the active non-circular gear and the driven non-circular gear; the final angular compensation amount is obtained by superimposing the compensation value of the systematic error component and the filtering result of the random error component according to a fixed weight of 7:3, wherein the weight proportion of the compensation value of the systematic error component is higher.

[0014] Further, the controller dynamically distributes the rotation angle compensation amount according to the current pitch curve position of the driving non-circular gear when generating the corrected motor control signal, increases the adjustment weight of the rotation angle compensation amount when the meshing point of the driving non-circular gear and the driven non-circular gear is close to the long axis end point of the pitch curve, and decreases the adjustment weight of the rotation angle compensation amount when the meshing point is close to the short axis end point of the pitch curve, so as to adapt to the difference in error sensitivity of the non-circular gear at different meshing positions; after the servo driver receives the corrected motor control signal, the non-circular gear driving module inside the servo driver adjusts the dynamic response characteristics of the output current in real time according to the pitch curve parameters and the current rotation angle position of the driving non-circular gear, and automatically increases the proportional gain and integral time constant of the current loop in the area where the pitch curve radius of curvature is small, so as to cause the load torque to suddenly change.

[0015] Further, when the controller dynamically distributes the rotation angle compensation amount according to the current pitch curve position of the driving non-circular gear, the controller calls the pre-stored pitch curve profile data of the driving non-circular gear, identifies the long axis end point, the short axis end point and the feature inflection points of the pitch curve, divides the pitch curve into a plurality of meshing areas corresponding to the profile changes, and the boundary points of each meshing area correspond to the extreme points of the pitch curve curvature; when the meshing point is in the area where the long axis end point is located, the controller sets the adjustment weight of the rotation angle compensation amount to the highest, and the weight value gradually decreases as the meshing point moves towards the short axis end point, and the decreasing trend is consistent with the decreasing trend of the pitch curve radius of curvature; when the meshing point is in the area where the short axis end point is located, the adjustment weight remains the lowest, and when the meshing point passes through the short axis end point, the weight temporary storage mechanism is triggered, so that the compensation amount remains stable at this position; at the same time, the controller tracks the rotation angle change rate of the driving non-circular gear in real time, and when a sudden change in the rotation angle change rate is detected, the adjustment weight is increased to compensate for the dynamic transmission error, and after the sudden change ends, the original weight value is restored.

[0016] Further, the non-circular gear drive module inside the servo driver pre-stores the correspondence relationship data of the curvature radius of the active non-circular gear pitch curve and the load characteristic, which records the theoretical load state and the reference value of the current loop control parameter corresponding to different angular positions; when receiving the corrected motor control signal, the drive module determines the curvature radius range of the pitch curve area according to the current angular position of the active non-circular gear, and if the curvature radius is in a smaller interval, the control parameters of the current loop are automatically adjusted: the proportional gain is increased to improve the response speed, and the integral time constant is prolonged to enhance the anti-load disturbance ability, and the parameter adjustment amplitude increases with the decrease of the curvature radius; when the curvature radius is in a larger interval, the drive module keeps the current loop parameters as the reference value, and enables the load feedforward compensation function, and outputs the current compensation signal in advance according to the pre-stored theoretical load characteristic data, and the output of the compensation signal is synchronized with the angular position of the active non-circular gear; when the meshing point enters another area from one pitch curve area, the drive module adjusts the current loop parameters through the smooth transition algorithm to avoid the motor output fluctuation caused by parameter mutation, and the transition process matches the change rate of the pitch curve profile.

[0017] The beneficial effects of the present application are as follows: the present application effectively solves the problem of relying on the prior mechanical precision or simple feedback regulation and lacking real-time error online compensation ability by constructing a synchronous control system integrating non-circular gear feature detection and dynamic compensation. By setting a grating code disc matched with the pitch curve profile of the non-circular gear and a dynamic sampling trigger module, combined with a customized motor encoder, the instantaneous transmission ratio fluctuation in the non-uniform speed transmission process and the pitch curve meshing phase difference are accurately perceived; the controller can dynamically calculate the theoretical angle of the driven wheel based on the discrete coordinate point set of the pitch curve and the piecewise interpolation algorithm, and separate the system error and the random error through error coupling analysis, combined with the pitch curve inverse solution compensation and the variable step size filtering algorithm, to realize real-time correction of the pitch curve profile error, meshing gap and other multi-source errors. At the same time, the servo driver dynamically adjusts the current loop parameters according to the curvature radius of the pitch curve, and cooperates with the dynamic weight distribution of the angle compensation amount, which significantly improves the transmission stability of the non-circular gear in the curvature mutation area. The system effectively avoids the paper feeding deviation and equipment failure caused by error accumulation, and provides reliable technical support for high-precision intermittent conveying scenes. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 is the intermittent paper feeding mechanism non-circular gear transmission real-time error compensation and synchronous control system principle diagram of the present application. DETAILED DESCRIPTION

[0019] The following non-limiting examples can make the ordinary skilled in the art more comprehensive understanding of the present application, but not in any way limit the present application, it is necessary to point out that the following examples can not be understood as limiting the scope of the present application, if the skilled in the art according to the above content of the present application to make some non-essential improvements and adjustment of the present application, still belongs to the scope of the present application.

[0020] Please refer to Figure 1 The embodiment of the present application provides a kind of intermittent paper feeding mechanism noncircular gear transmission real-time error compensation and synchronization control system, comprising: double noncircular gear transmission assembly, drive motor, noncircular gear pitch curve feature detection unit, paper feeding position detection unit, controller and servo driver;Double noncircular gear transmission assembly, including driving noncircular gear and driven noncircular gear, driving noncircular gear is rigidly connected with the output shaft of drive motor, driven noncircular gear is mechanically coupled with paper feeding execution mechanism by transmission shaft, and driving noncircular gear and driven noncircular gear mesh transmission;Drive motor, for driving driving noncircular gear to rotate, built-in motor encoder, motor encoder real-time acquisition driving noncircular gear's rotation position signal;Noncircular gear pitch curve feature detection unit, including fixed in the first grating scale disc of driving noncircular gear end face, fixed in the second grating scale disc of driven noncircular gear end face, and respectively with the grating scale disc, second grating scale disc corresponding setting grating read head, grating read head is electrically connected with controller by signal line, for real-time acquisition driving noncircular gear and driven noncircular gear's pitch curve actual rotation difference signal;Paper feeding position detection unit, including fixed in the laser interferometer of paper feeding execution mechanism movement track end, the detection light path of laser interferometer is parallel with the displacement direction of paper feeding execution mechanism, for real-time acquisition paper feeding execution mechanism's actual displacement signal;Controller, built-in noncircular gear theoretical transmission model storage module, theoretical transmission model storage module prestore driving noncircular gear and driven noncircular gear's pitch curve parameter and theoretical transmission ratio function, controller is electrically connected with motor encoder, grating read head, laser interferometer by signal line, and by control bus and the servo driver of drive motor bidirectional communication;Servo driver, input end is electrically connected with controller, output end is electrically connected with drive motor, for receiving control signal and driving motor operation.

[0021] The double non-circular gear transmission assembly as a core transmission component, through the meshing of the driving non-circular gear and the driven non-circular gear, realizes the transmission of non-uniform speed movement, the driving non-circular gear is rigidly connected with the driving motor to ensure the power transmission without delay, and the mechanical coupling of the driven non-circular gear and the paper feeding execution mechanism directly determines the precision of the paper feeding action; the motor encoder built in the driving motor provides the driving wheel angular position reference for the system, and the real-time collected signal is the basis for subsequent theoretical model solving and error analysis; the non-circular gear pitch curve feature detection unit directly collects the pitch curve actual angle difference signal of the driving and driven wheels through the cooperation of the double grating code disc and the grating reader, the signal can reflect the phase deviation in the non-circular gear meshing process, and is the key basis for detecting the pitch curve profile error; the paper feeding position detection unit realizes the end displacement feedback by using a laser interferometer, the detection light path parallel to the motion trajectory ensures the high-precision collection of the displacement signal, and provides protection for the final output verification of the transmission error; the controller as the system center, through the integration of multiple source detection signals and theoretical models, realizes error analysis and compensation instruction generation, and the electrical connection with each hardware module and the control bus communication ensure the real-time of signal transmission; the servo driver dynamically adjusts the motor output according to the controller instruction, and realizes error closed-loop compensation by correcting the angle of the driving non-circular gear.

[0022] The intermittent paper feeding mechanism non-circular gear transmission real-time error compensation and synchronous control system of the application adopts the following mode for real-time error compensation and synchronous control: the motor encoder collects the rotation position signal of the driving non-circular gear in real time and transmits the rotation position signal to the controller; the first grating disc and the second grating disc synchronously collect the actual rotation difference signal of the pitch curve of the driving non-circular gear and the driven non-circular gear through the grating reader and transmit the actual rotation difference signal to the controller; the laser interferometer collects the actual displacement signal of the paper feeding execution mechanism in real time and transmits the actual displacement signal to the controller; the controller calls the built-in non-circular gear theoretical transmission model storage module, calculates the theoretical rotation value of the driven non-circular gear and the theoretical displacement value of the paper feeding execution mechanism based on the rotation position signal of the driving non-circular gear, and in combination with the pre-stored pitch curve parameters and the theoretical transmission ratio function; the controller compares the actual rotation difference signal of the pitch curve with the theoretical rotation difference calculated based on the theoretical rotation value of the driven non-circular gear to obtain the pitch curve meshing error; compares the actual displacement signal of the paper feeding execution mechanism with the theoretical displacement value to obtain the paper feeding displacement error; based on the periodic meshing characteristics of the non-circular gear pitch curve, the pitch curve meshing error and the paper feeding displacement error are coupled and analyzed to obtain the rotation compensation amount of the driving non-circular gear; the controller superimposes the rotation compensation amount to the theoretical rotation instruction of the driving non-circular gear to generate the corrected motor control signal and transmits the corrected motor control signal to the servo driver through the control bus; the servo driver adjusts the output rotation speed and rotation angle of the driving motor according to the corrected motor control signal to drive the driving non-circular gear to correct the pitch curve meshing phase, and drives the driven non-circular gear to be synchronously adjusted through the meshing transmission of the double non-circular gears, until the pitch curve meshing error and the paper feeding displacement error are both less than the preset threshold.

[0023] The real-time error compensation and synchronous control process realizes dynamic correction of the non-circular gear transmission error through the closed-loop design of "signal collection-theoretical calculation-error analysis-compensation execution". The synchronous collection of multiple source signals ensures the comprehensiveness of error analysis, the rotation position signal of the motor encoder provides input reference for the theoretical model, the actual rotation difference signal of the pitch curve reflects the gear meshing phase deviation, and the actual displacement signal verifies the end output accuracy; the calling and solving process of the theoretical transmission model generates the theoretical rotation value and displacement value based on the pitch curve parameters and the transmission ratio function to provide ideal reference for error comparison; the coupling analysis of the pitch curve meshing error and the paper feeding displacement error comprehensively considers the gear meshing deviation and the transmission chain end output error, and realizes the associated compensation of multiple source errors through the periodic characteristics of the non-circular gear; the superposition of the rotation compensation amount and the execution of the servo driver ensure the real-time of the phase correction of the driving non-circular gear, and the synchronous adjustment of the double gears makes the error quickly converge to the threshold range.

[0024] In the embodiment, the motor encoder is an encoder with non-circular gear rotation angle correction function, which pre-stores the pitch curve profile characteristic parameters of the driving non-circular gear inside, can dynamically adjust the sampling frequency according to the actual rotation position of the driving non-circular gear, automatically increases the sampling density of the rotation angle position signal in the area where the pitch curve curvature radius change rate is greater than the preset threshold, and keeps the preset sampling density in the area where the pitch curve curvature radius change rate is less than the preset threshold; the grating line patterns of the first and second grating code discs correspond to the pitch curve shapes of the driving and driven non-circular gears respectively, and the radial spacing of the grating lines changes synchronously with the curvature radius of the corresponding non-circular gear pitch curve, so that the actual rotation angle difference signal of the pitch curve collected by the grating reader directly contains the instantaneous transmission ratio fluctuation information in the meshing process of the non-circular gear; the measurement light path of the laser interferometer is provided with a dynamic sampling trigger module matched with the non-circular gear transmission period, which can increase the collection frequency of the actual displacement signal when the paper feeding execution mechanism is in the non-uniform speed movement stage according to the driving non-circular gear rotation position signal sent by the controller, and reduce the collection frequency when the paper feeding execution mechanism is in the intermittent pause stage; the pre-stored pitch curve parameters in the non-circular gear theoretical transmission model storage module include the discretized coordinate point set corresponding to the actual pitch curve equation of the driving and driven non-circular gears, and the theoretical transmission ratio function is a transmission ratio curve varying with the rotation angle of the driving non-circular gear calculated according to the pitch curve parameters of the driving and driven non-circular gears; when calculating the theoretical rotation angle value of the driven non-circular gear, the controller determines the current position of the driving non-circular gear in the pitch curve according to the rotation angle position signal of the driving non-circular gear, and calculates the theoretical rotation angle value of the driven non-circular gear corresponding to the current rotation angle of the driving non-circular gear by querying the pre-stored discretized coordinate point set and the theoretical transmission ratio curve and using the piecewise linear interpolation algorithm.

[0025] The motor encoder with non-circular gear rotation angle correction function realizes dynamic adjustment of the sampling frequency by pre-storing the pitch curve profile parameters, increases the sampling density in the high curvature change area, ensures accurate capture of non-uniform rotation, and avoids information loss in the nonlinear area caused by fixed sampling; the grating code disc matched with the pitch curve shape changes the radial spacing of the grating lines synchronously with the curvature radius, so that the collected pitch curve actual rotation angle difference signal directly contains the instantaneous transmission ratio fluctuation information, and the transmission characteristics of the non-circular gear can be reflected without additional calculation; the dynamic sampling trigger module of the laser interferometer adjusts the collection frequency according to the rotation angle position of the driving gear, increases the frequency in the non-uniform speed stage to capture the detail error, and reduces the frequency in the pause stage to save resources, achieving a balance between sampling efficiency and accuracy; the combination of the discretized coordinate point set in the theoretical transmission model and the piecewise linear interpolation algorithm enables the calculation of the theoretical rotation angle value of the driven gear to adapt to the nonlinear characteristics of the pitch curve, and quickly generates high-precision theoretical reference values by querying the pre-stored data and interpolation operation, providing a reliable basis for error analysis.

[0026] In the embodiment, the controller divides the whole rotation angle of the driving non-circular gear into a plurality of rotation angle intervals corresponding to the characteristic points of the pitch curve when determining the current position of the driving non-circular gear in the pitch curve, the starting point and the ending point of each rotation angle interval correspond to the curvature extreme points or the inflection points of the pitch curve, the discrete coordinate point set is stored in segments according to the above rotation angle intervals, and the density of the coordinate points in each rotation angle interval increases with the increase of the curvature change rate of the pitch curve; after receiving the rotation angle position signal transmitted by the motor encoder, the controller determines the target rotation angle interval to which the rotation angle position signal belongs through the interval matching algorithm, and then identifies the profile position of the pitch curve in which the driving non-circular gear is currently located according to the pre-stored discrete coordinate point set of the pitch curve in the interval through the characteristic point comparison, wherein the controller calls the high-precision interpolation submodule for coordinate point matching in the rotation angle interval in which the curvature radius change rate is greater than the preset threshold, and calls the regular matching submodule in the interval in which the curvature radius change rate is less than the preset threshold; when querying the pre-stored discrete coordinate point set and the theoretical transmission ratio curve, the controller adopts the chain query structure corresponding to the engagement sequence of the non-circular gears, calls the pitch curve coordinate data of the driving non-circular gear in the current rotation angle interval from the discrete coordinate point set, and synchronously calls the pitch curve coordinate data of the corresponding engagement interval of the driven non-circular gear and the theoretical transmission ratio curve segment, the theoretical transmission ratio curve segment is stored in segments according to the rotation angle interval of the driving non-circular gear, and each segment of the curve contains a transmission ratio correction coefficient corresponding to the curvature change of the pitch curve; when calculating the theoretical rotation angle value of the driven non-circular gear by using the piecewise linear interpolation algorithm, the controller selects two adjacent discrete coordinate points in the target rotation angle interval as the interpolation base points according to the current rotation angle position signal of the driving non-circular gear, wherein the former base point is the nearest pitch curve characteristic point before the current rotation angle position, and the latter base point is the nearest pitch curve characteristic point after the current rotation angle position, then according to the theoretical transmission ratio values corresponding to the two base points and the deviation amount of the current rotation angle from the base point rotation angle, the instantaneous theoretical transmission ratio of the current position is calculated through weighted interpolation, the rotation angle increment of the driving non-circular gear is multiplied by the instantaneous theoretical transmission ratio, and is superimposed to the initial theoretical rotation angle value of the driven non-circular gear to obtain the real-time theoretical rotation angle value of the driven non-circular gear, wherein in the interval in which the curvature change rate of the pitch curve is greater than the preset threshold, the weight coefficient of the interpolation calculation dynamically shifts to the side with the greater curvature change rate.

[0027] The division of the corner interval is bound to the feature point, so that the storage of the discrete coordinate point set of the pitch curve is associated with the geometric feature, and the high-density coordinate points in the high-curvature change interval ensure the fine description of the nonlinear profile; the combination of the interval matching algorithm and the feature point comparison realizes the rapid positioning of the corner position signal to the pitch curve profile position, the calling of the high-precision interpolation submodule and the conventional submodule dynamically adjusts the matching accuracy according to the curvature characteristics, and the efficiency and accuracy are considered; the chain query structure and the segmented storage of the theoretical transmission ratio curve segment synchronize the data retrieval of the meshing interval of the driving and driven wheels, and the introduction of the transmission ratio correction coefficient ensures the real-time adaptation of the transmission ratio function to the curvature change of the pitch curve; the base point selection and weighted calculation in the piecewise linear interpolation dynamically generates the instantaneous theoretical transmission ratio through the theoretical transmission ratio value and the deviation of the feature points before and after the current corner, and the weight offset of the high-curvature interval further improves the interpolation accuracy of the nonlinear region, and the finally obtained real-time theoretical corner value can accurately reflect the ideal motion state of the driven wheel.

[0028] In the embodiment, when performing non-circular gear meshing error coupling analysis, the controller synchronizes the pitch curve actual corner difference signal and the paper feeding actuator actual displacement signal on the time axis according to the corner position of the driving non-circular gear; the periodic variation characteristics of the pitch curve meshing error and the paper feeding displacement error in the process of one rotation of the driving non-circular gear are extracted, and the main period and harmonic components of the error variation are identified, wherein the main period is consistent with the meshing period of the non-circular gear; according to the closed characteristic of the pitch curve of the non-circular gear, the pitch curve meshing error and the paper feeding displacement error in one meshing period are decomposed into a system error component related to the pitch curve profile and a random error component related to the meshing gap and elastic deformation, a compensation algorithm based on the inverse solution of the pitch curve is adopted for the system error component, an adaptive filtering algorithm is adopted for the random error component, and finally the results of the two algorithms are superimposed to obtain the corner compensation amount of the driving non-circular gear.

[0029] The time axis synchronization takes the corner position of the driving non-circular gear as the reference, ensures the accurate association of the pitch curve meshing error and the paper feeding displacement error at the same corner, and avoids the error misjudgment caused by different time sampling; the extraction of the periodic variation characteristics of the error identifies the main period and the harmonic components based on the meshing period of the non-circular gear, so that the error analysis focuses on the inherent periodic deviation of the gear transmission; the decomposition of the system error component and the random error component distinguishes the profile-related error and the dynamic interference error based on the closed characteristic of the pitch curve, the compensation algorithm based on the inverse solution of the pitch curve is used for the purpose of correcting the system error, and the adaptive filtering algorithm effectively suppresses the random error, and the superimposed corner compensation amount realizes the collaborative correction of multiple error sources.

[0030] In the embodiment, when the controller time-axis synchronizes the actual angle difference signal of the pitch curve and the actual displacement signal of the paper feeding actuator according to the rotation angle position of the driving non-circular gear, the rotation angle position signal of the driving non-circular gear is taken as the synchronization reference axis, the scale division of the reference axis corresponds to the closed period of the pitch curve of the driving non-circular gear one by one, and one complete pitch curve period corresponds to one rotation; the controller is internally provided with a rotation angle-time mapping table, the mapping table pre-stores the theoretical time stamp corresponding to different rotation angle positions of the driving non-circular gear, the time synchronization deviation value is calculated by comparing the collection time stamp of the actual angle difference signal of the pitch curve and the actual displacement signal with the theoretical time stamp in the mapping table, and the sampling points of the two signals are dynamically aligned according to the deviation value, so as to ensure that the pitch curve meshing error and the paper feeding displacement error at the same rotation angle position can be accurately associated, wherein the synchronization accuracy at the long axis and short axis end positions of the pitch curve of the driving non-circular gear is set to be higher than that at other positions; when the controller extracts the periodic variation characteristics of the pitch curve meshing error and the paper feeding displacement error during one rotation of the driving non-circular gear, a segmented period extraction method based on pitch curve feature points is adopted, the start and end points of the closed period of the pitch curve of the driving non-circular gear are identified, the maximum curvature radius point of the pitch curve is taken as the period start point, the whole rotation process is divided into a plurality of feature segments corresponding to the profile change of the pitch curve, the length of each feature segment is dynamically adjusted according to the curvature radius variation rate of the pitch curve, and the feature segments in the region with large curvature variation rate are divided more finely; the error signals in each feature segment are independently subjected to period analysis, the local period components in each feature segment are extracted, and then the local period components are subjected to coupling operation with the whole period, so as to finally identify the main period and harmonic components of the error variation, wherein the extraction weight of the main period is inclined to the feature segments with large curvature variation rate of the pitch curve.

[0031] The combination of the rotation angle-time mapping table and dynamic alignment, the correction of the sampling time deviation of the actual signal based on the theoretical time stamp of the driving gear, the high-precision synchronization setting of the long axis and short axis end points, and the error association accuracy of the high-sensitivity positions are ensured; the segmented period extraction based on the pitch curve feature points corresponds the whole rotation process to the profile change through feature segment division, the feature segments in the region with large curvature variation rate are finely divided, and the extraction of the local period components is more in line with the details of the error variation; the coupling operation of the local period components with the whole period, in combination with the inclination of the main period extraction weight, highlights the error period characteristics of the high-curvature region, and the identified main period and harmonic components can accurately reflect the periodicity of the non-circular gear meshing error.

[0032] In the embodiment, the controller calls the pre-stored active non-circular gear and driven non-circular gear pitch curve profile data when decomposing the error component according to the closed characteristic of the non-circular gear pitch curve, calculates the theoretical meshing gap through the pitch curve profile comparison algorithm, and takes the theoretical meshing gap as the basic threshold of the system error component; for the pitch curve meshing error, the part of the error value that is consistent with the deviation trend of the pitch curve profile data and has a regular change in amplitude with the angular position is determined as the system error component, and the part of the error value that exceeds the range of the theoretical meshing gap and has no obvious change is determined as the random error component; for the paper feeding displacement error, the part of the displacement error that is linearly related to the change of the pitch curve profile is separated as the system error component through the establishment of the pitch curve profile-displacement transfer function, and the remaining part is further decomposed into the random error component combined with the output torque fluctuation data of the driving motor, wherein the decomposition process of the system error component needs to introduce the pitch curve closed constraint condition, and the integral sum of the system error component in one period is zero; the compensation algorithm based on the inverse solution of the pitch curve realizes the compensation process for the system error component by calling the inverse solution model of the non-circular gear pitch curve, which can inversely calculate the profile parameters of the active non-circular gear pitch curve that need to be corrected according to the currently identified system error component; the controller calculates the compensation coefficient of the active non-circular gear at each angular position according to the correction amount of the pitch curve profile parameter, which increases with the increase of the pitch curve curvature radius and decreases with the decrease of the pitch curve curvature radius; the adaptive filtering algorithm adopts a variable step-size filtering strategy matched with the non-circular gear meshing frequency for the compensation process of the random error component, and the size of the filtering window is dynamically adjusted according to the angular position of the current active non-circular gear, narrow window filtering is used in the area where the pitch curve meshing frequency is higher than the preset threshold, and wide window filtering is used in the area where the meshing frequency is lower than the preset threshold, while the filtering coefficient is set to be positively correlated with the real-time meshing gap of the active non-circular gear and the driven non-circular gear; the final angular compensation amount is obtained by superimposing the compensation value of the system error component and the filtering result of the random error component according to a fixed weight of 7:3, wherein the weight proportion of the compensation value of the system error component is higher.

[0033] The calculation of the theoretical meshing gap and the setting of the system error component threshold value realize the quantitative distinction of the system error and the random error based on the profile curve contour comparison, and the closed constraint condition of the profile curve ensures the periodicity of the system error component; the calling of the profile curve inverse solution model and the calculation of the profile parameter correction quantity make the compensation of the system error component directly act on the profile curve of the driving non-circular gear, and the change law of the compensation coefficient with the curvature radius adapts to the error sensitivity of the non-circular gear at different positions; the matching of the variable step filtering strategy and the meshing frequency makes the random error component suppression effect change with the meshing state through dynamic adjustment of the filtering window size and the filtering coefficient, and the correlation setting of the real-time meshing gap enhances the adaptability of the filtering to the dynamic interference; the weighted superposition of the system error and the random error compensation results gives priority to the system error compensation, ensuring the priority correction of the profile curve inherent error, and the finally generated rotation angle compensation quantity can comprehensively offset the multi-source error.

[0034] In the embodiment, when generating the corrected motor control signal, the controller dynamically allocates the rotation angle compensation quantity according to the current profile curve position of the driving non-circular gear, increases the adjustment weight of the rotation angle compensation quantity when the meshing point of the driving non-circular gear and the driven non-circular gear is close to the long axis endpoint of the profile curve, and reduces the adjustment weight of the rotation angle compensation quantity when the meshing point is close to the short axis endpoint of the profile curve, so as to adapt to the difference in error sensitivity of the non-circular gear at different meshing positions; after the servo driver receives the corrected motor control signal, the non-circular gear driving module inside the servo driver adjusts the dynamic response characteristics of the output current in real time according to the profile curve parameters and the current rotation angle position of the driving non-circular gear, and automatically increases the proportional gain and integral time constant of the current loop in the area where the profile curve radius of curvature is small, resulting in sudden change of the load torque.

[0035] The dynamic weight allocation of the rotation angle compensation quantity adjusts the weight based on the position of the meshing point at the long axis and the short axis endpoint of the profile curve, adapts to the difference in error sensitivity of the non-circular gear at different meshing positions, the high weight at the long axis endpoint ensures effective correction of the error in the high sensitivity area, and the low weight at the short axis endpoint avoids overcompensation; the non-circular gear driving module of the servo driver adjusts the current loop parameters according to the profile curve parameters and the current rotation angle position, the proportional gain is increased and the integral time constant is prolonged in the area where the load torque suddenly changes, the response speed and anti-disturbance ability of the motor output are improved, and the accuracy of the rotation angle correction of the driving non-circular gear is ensured.

[0036] In the embodiment, the controller calls the pre-stored profile data of the active non-circular gear, identifies the long axis end point, the short axis end point and the feature inflection point of the profile curve, divides the profile curve into a plurality of meshing regions corresponding to the profile change, and the boundary points of each meshing region correspond to the extreme points of the curvature of the profile curve. When the meshing point is in the region where the long axis end point is located, the controller sets the adjustment weight of the rotation angle compensation amount to the highest, and the weight value gradually decreases as the meshing point moves towards the short axis end point, and the decreasing trend is consistent with the decreasing trend of the curvature radius of the profile curve. When the meshing point is in the region where the short axis end point is located, the adjustment weight remains the lowest, and when the meshing point passes through the short axis end point, the weight temporary storage mechanism is triggered to keep the compensation amount stable at this position. At the same time, the controller tracks the rotation angle change rate of the active non-circular gear in real time, and when a sudden change in the rotation angle change rate is detected, the adjustment weight is increased to compensate for the dynamic transmission error, and the original weight value is restored after the sudden change ends.

[0037] The calling of the profile curve data and the division of the meshing region divide the profile curve into regions corresponding to the profile change based on the long axis end point, the short axis end point and the feature inflection point, and the boundary points correspond to the curvature extreme points to ensure the accuracy of the region division. The highest adjustment weight in the long axis region and the gradual decrease towards the short axis direction ensure that the weight change trend is consistent with the decrease of the curvature radius, realizing the dynamic matching of the compensation intensity and the error sensitivity. The lowest weight in the short axis region and the weight temporary storage mechanism avoid the sudden change of the compensation amount near the transmission dead zone and ensure the system stability. The increase of the weight when the rotation angle change rate suddenly changes provides additional compensation for the dynamic transmission error caused by the sudden change of the curvature of the profile curve, and the weight recovery after the sudden change balances the dynamic correction and the system stability.

[0038] In the embodiment, the non-circular gear driving module in the servo driver pre-stores the correspondence data of the curvature radius of the profile curve of the active non-circular gear and the load characteristic, which records the theoretical load state and the reference value of the current loop control parameter corresponding to different rotation angle positions. When receiving the corrected motor control signal, the driving module determines the curvature radius range of the profile curve region according to the current rotation angle position of the active non-circular gear. If it is detected that the curvature radius is in a smaller interval, the control parameters of the current loop are automatically adjusted: the proportional gain is increased to improve the response speed, and the integral time constant is prolonged to enhance the anti-load disturbance ability, and the parameter adjustment amplitude increases with the decrease of the curvature radius. When the curvature radius is in a larger interval, the driving module keeps the current loop parameters at the reference value, and enables the load feedforward compensation function to output the current compensation signal in advance according to the pre-stored theoretical load characteristic data, and the output of the compensation signal is synchronized with the rotation angle position of the active non-circular gear. When the meshing point enters another region from one profile curve region, the driving module adjusts the current loop parameters through a smooth transition algorithm to avoid the motor output fluctuation caused by parameter mutation, and the transition process matches the change rate of the profile curve contour.

[0039] The pre-storage of the correspondence data between the radius of curvature and the load characteristics enables the driving module to predict the load state and the current loop parameter demand according to the rotation angle position; the current loop parameter adjustment in the small radius of curvature interval, the proportional gain increase and the integral time constant extension, specifically improve the motor response and the anti-disturbance ability in the load torque mutation region, and the parameter adjustment amplitude is positively correlated with the decrease of the radius of curvature, so that the accurate adaptation of the dynamic parameters is realized; the reference parameter maintenance and the load feedforward compensation in the large radius of curvature interval, through the pre-storage of the theoretical load data, the current compensation signal is output in advance, and the real-time of the feedforward is ensured through the synchronization of the compensation and the rotation angle position; the smooth transition algorithm during the meshing region switching, the current loop parameter adjustment process and the pitch curve profile change rate are matched, the motor output fluctuation caused by the parameter mutation is avoided, and the smoothness of the transmission process is ensured.

[0040] To further improve the signal synchronization accuracy and the anti-interference ability of the system, a distributed clock synchronization architecture can be adopted at the hardware level, a high-precision crystal oscillator built-in the controller is used to provide a unified time base signal for the motor encoder, the grating reader and the laser interferometer, and an optical fiber transmission link is added between each detection unit and the controller to reduce the signal transmission delay. For the time synchronization deviation problem caused by the motor speed fluctuation, the controller collects the rotation angle acceleration signal of the driving non-circular gear in real time, corrects the theoretical time stamp by establishing a rotation angle-time dynamic mapping model, and dynamically compensates the pre-stored theoretical time stamp according to the current rotation angle change rate in each sampling period. At the key positions such as the long axis and the short axis endpoints of the pitch curve, a high-precision time stamp calibration mechanism is triggered synchronously, the system clock is corrected by microseconds through the external trigger signal of the laser interferometer, and the accurate association of multiple source error signals at the same rotation angle position is ensured.

[0041] To enhance the robustness of error component separation, an online meshing gap monitoring module can be introduced, which is composed of a micro-torque sensor installed on the driven non-circular gear transmission shaft and a gap calculation unit. The controller collects the torque fluctuation signal in real time, combines with the pre-stored pitch curve profile data, establishes a dynamic calculation model of the meshing gap, and dynamically adjusts the basic threshold of the system error component according to the real-time meshing gap. When the detected meshing gap exceeds the preset wear threshold, the pitch curve profile parameter update process is automatically triggered, and the corrected pitch curve discrete coordinate point set is obtained by calling the historical error data and the current gap value. For the decomposition of the paper feeding displacement error, a transmission chain stiffness compensation term is further introduced, a three-dimensional transfer function of “pitch curve profile-torque-displacement” is established, the displacement deviation caused by elastic deformation is separated from the random error component, and the stiffness coefficient matrix varying with the rotation angle is obtained through the combination of finite element simulation and experimental calibration.

[0042] To meet the real-time requirement of the compensation algorithm, the controller can use a heterogeneous computing architecture: the main CPU is responsible for error coupling analysis and compensation instruction generation, and the coprocessor is responsible for multi-source signal acquisition, piecewise linear interpolation and other parallel computing tasks. A special hardware acceleration module is implemented inside the coprocessor, including a fast query engine for pitch curve coordinate point set and parallel logic for dynamic allocation of corner compensation amount. To reduce the complexity of the algorithm, the number of interpolation base points in the high-curvature area is dynamically adjusted according to the curvature rate of change. When the curvature rate of change is large, the number of interpolation base points is increased and a high-order interpolation algorithm is used to improve accuracy. When the curvature rate of change is small, linear interpolation with fewer base points is maintained. The controller also has a built-in computing resource monitoring module that automatically enables a simplified algorithm to ensure that the core control period is not affected when the CPU load rate is too high.

[0043] To cover the end error of the transmission chain, the system can add multiple stages of grating position feedback in the transmission shaft system of the paper feeding actuator. The cumulative error of the transmission chain is calculated by comparing the rotation angle difference signals of each stage of transmission shaft, and it is introduced as an additional error component into the compensation model, using a feedforward-feedback composite control strategy. The feedforward channel outputs the compensation amount in advance according to the pre-stored transmission chain stiffness data, and the feedback channel corrects the residual error in real time through the last stage grating signal. For nonlinear errors caused by guide rail clearance, a clearance compensation term is added to the displacement signal of the laser interferometer, and a "displacement-velocity-clearance" dynamic model is established to automatically trigger a clearance compensation pulse when the paper feeding actuator reverses, with the width of the compensation pulse being negatively related to the current movement speed.

[0044] The system also has self-diagnosis and health management functions, which monitor the running state of each module in real time, establish a performance degradation evaluation model, and automatically generate maintenance recommendations when key parameters exceed the warning threshold and upload them to the upper computer monitoring system through industrial Ethernet. At the software level, a modular design architecture is used to support OTA upgrade to update the control algorithm and theoretical model parameters, adapt to the application requirements of different specifications of non-circular gears, and extend the time to replace the pitch curve parameter file and error compensation coefficient matrix without modifying the underlying control logic.

[0045] From the above embodiments, the application constructs a full-link real-time error compensation and synchronization control scheme for the double non-circular gear transmission of the intermittent paper feeding mechanism, and realizes precise correction of the transmission error unique to the non-circular gear. The dynamic sampling encoder, grating code disc and laser interferometer matched with the pitch curve profile are used in combination with the controller to realize multi-dimensional high-precision sensing of the rotation angle, phase and displacement in the non-uniform speed transmission process. Based on the customized methods of pitch curve discretization modeling and piecewise interpolation, error period coupling analysis, system-random error separation compensation and the like, the dependence of the general control on the uniform speed transmission is broken, and real-time calculation and compensation of the pitch curve profile error, meshing gap, dynamic deformation and other errors unique to the non-circular gear are realized. Through dynamic weight distribution of the rotation angle compensation amount and adaptive adjustment of the servo drive parameters, the compensation strategy is dynamically matched with the error sensitivity and load characteristics of the non-circular gear at different meshing positions. The scheme deeply integrates the geometric characteristics, motion characteristics and control algorithm of the non-circular gear, effectively solves the problem of the prior art that relies on the mechanical precision in the early stage or simple feedback regulation and lacks real-time error online compensation capability, and significantly improves the transmission accuracy and stability of the intermittent paper feeding mechanism.

[0046] The above-mentioned embodiments of the application do not constitute a limitation on the protection scope of the application.

Claims

1. A real-time error compensation and synchronization control system for an intermittent paper feed mechanism non-circular gear drive, characterized in that, The application relates to a double non-circular gear transmission assembly, a driving motor, a non-circular gear pitch curve characteristic detection unit, a paper feeding position detection unit, a controller and a servo driver. The double non-circular gear transmission assembly comprises a driving non-circular gear and a driven non-circular gear, the driving non-circular gear is connected with an output shaft of the driving motor, the driven non-circular gear is connected with a paper feeding execution mechanism through a transmission shaft, and the driving non-circular gear and the driven non-circular gear are in mesh transmission. The driving motor is used for driving the driving non-circular gear to rotate, and a motor encoder is arranged in the driving motor. The non-circular gear pitch curve characteristic detection unit comprises a first grating code disc fixed to an end surface of the driving non-circular gear, a second grating code disc fixed to an end surface of the driven non-circular gear and grating readers correspondingly arranged with the first grating code disc and the second grating code disc. The paper feeding position detection unit comprises a laser interferometer fixed to the end of a movement track of the paper feeding execution mechanism. The controller is internally provided with a non-circular gear theoretical transmission model storage module, the theoretical transmission model storage module pre-stores pitch curve parameters and a theoretical transmission ratio function of the driving non-circular gear and the driven non-circular gear. The servo driver is electrically connected with the controller at the input end and electrically connected with the driving motor at the output end, and is used for receiving a control signal and driving the motor to operate. The motor encoder collects the rotation angle position signal of the driving non-circular gear in real time and transmits the rotation angle position signal to the controller.

2. The real-time error compensation and synchronization control system for the non-circular gear transmission of the intermittent paper feed mechanism according to claim 1, characterized in that, The controller calls the built-in non-circular gear theoretical transmission model storage module, calculates the theoretical rotation angle value of the driven non-circular gear and the theoretical displacement value of the paper feeding execution mechanism based on the rotation angle position signal of the driving non-circular gear and in combination with the pre-stored pitch curve parameters and the theoretical transmission ratio function. The controller compares the pitch curve actual rotation angle difference signal with the theoretical rotation angle difference calculated based on the theoretical rotation angle value of the driven non-circular gear, obtains the pitch curve meshing error, compares the actual displacement signal of the paper feeding execution mechanism with the theoretical displacement value, obtains the paper feeding displacement error, and based on the periodic meshing characteristics of the non-circular gear pitch curve, analyzes the pitch curve meshing error and the paper feeding displacement error, and calculates the rotation angle compensation amount of the driving non-circular gear. ​ ​ The controller superimposes the rotation angle compensation amount to the theoretical rotation angle instruction of the driving non-circular gear, generates a corrected motor control signal, and transmits the signal to the servo driver through a control bus; The servo driver adjusts the output rotation speed and rotation angle of the driving motor according to the corrected motor control signal, corrects the meshing phase of the non-circular gear pair, and drives the driven non-circular gear to adjust synchronously through the meshing transmission of the double non-circular gears, until the meshing error of the pitch curve and the paper feeding displacement error are both less than a preset threshold.

3. The real-time error compensation and synchronization control system for the non-circular gear transmission of the intermittent paper feed mechanism according to claim 2, wherein, The motor encoder is an encoder with a non-circular gear rotation angle correction function, which pre-stores the characteristic parameters of the pitch curve profile of the driving non-circular gear, can dynamically adjust the sampling frequency according to the actual rotation position of the driving non-circular gear, and automatically increases the sampling density of the rotation angle position signal in the area where the change rate of the pitch curve radius of curvature is greater than a preset threshold, and maintains a preset sampling density in the area where the change rate of the pitch curve radius of curvature is less than the preset threshold. The grating line patterns of the first and second grating code discs correspond one-to-one to the shapes of the pitch curves of the driving and driven non-circular gears, respectively, and the radial spacing of the grating lines changes synchronously with the curvature radius of the corresponding non-circular gear pitch curve, so that the actual rotation angle difference signal of the pitch curve collected by the grating reader directly contains the instantaneous transmission ratio fluctuation information in the meshing process of the non-circular gears; The measurement light path of the laser interferometer is provided with a dynamic sampling trigger module matched with the transmission period of the non-circular gears, which can increase the collection frequency of the actual displacement signal when the paper feeding actuator is in a non-uniform speed motion stage, and decrease the collection frequency when the paper feeding actuator is in an intermittent pause stage, according to the rotation angle position signal of the driving non-circular gear sent by the controller. The pitch curve parameters pre-stored in the non-circular gear theoretical transmission model storage module include a discrete coordinate point set corresponding to the actual pitch curve equation of the driving and driven non-circular gears, the theoretical transmission ratio function is a transmission ratio curve varying with the rotation angle of the driving non-circular gear calculated according to the pitch curve parameters of the driving and driven non-circular gears, and when calculating the theoretical rotation angle value of the driven non-circular gear, the controller determines the current position of the driving non-circular gear in the pitch curve according to the rotation angle position signal of the driving non-circular gear, queries the pre-stored discrete coordinate point set and the theoretical transmission ratio curve, and calculates the theoretical rotation angle value of the driven non-circular gear corresponding to the current rotation angle of the driving non-circular gear by using a piecewise linear interpolation algorithm.

4. The system for real-time error compensation and synchronization control of the non-circular gear transmission of the intermittent paper feed mechanism according to claim 3, wherein, When determining the current position of the driving non-circular gear in the pitch curve according to the rotation angle position signal of the driving non-circular gear, the controller divides the whole rotation angle of the driving non-circular gear into a plurality of rotation angle intervals corresponding one-to-one to the characteristic points of the pitch curve, the starting point and the ending point of each rotation angle interval correspond to the curvature extreme points or inflection points of the pitch curve, the discrete coordinate point set is stored in segments according to the above rotation angle intervals, and the density of the coordinate points in each rotation angle interval increases with the increase of the change rate of the curvature of the pitch curve. When receiving the rotation angle position signal transmitted by the motor encoder, the controller determines the target rotation angle interval to which the rotation angle position signal belongs through interval matching algorithm, and then identifies the current profile position of the active non-circular gear on the basis of the pre-stored discrete coordinate point set of the pitch curve in the interval through feature point comparison, wherein in the rotation angle interval in which the change rate of the curvature radius of the pitch curve is greater than a preset threshold, the controller calls the high-precision interpolation submodule to perform coordinate point matching, and in the interval in which the change rate of the curvature radius is less than the preset threshold, the controller calls the regular matching submodule; When querying the pre-stored discrete coordinate point set and the theoretical transmission ratio curve, the controller adopts a chain query structure corresponding to the engagement sequence of the non-circular gears, and according to the current rotation angle interval of the active non-circular gear, the controller calls the pitch curve coordinate data of the active non-circular gear in the interval from the discrete coordinate point set, and synchronously calls the pitch curve coordinate data of the corresponding engagement interval of the driven non-circular gear and the theoretical transmission ratio curve segment, wherein the theoretical transmission ratio curve segment is stored in segments according to the rotation angle interval of the active non-circular gear, and each segment of the curve contains a transmission ratio correction coefficient corresponding to the change of the pitch curve curvature; When the segmented linear interpolation algorithm is used to calculate the theoretical rotation angle value of the driven non-circular gear, the controller selects two adjacent discrete coordinate points in the target rotation angle interval as interpolation base points according to the current rotation angle position signal of the active non-circular gear, wherein the former base point is the nearest pitch curve feature point before the current rotation angle position, and the latter base point is the nearest pitch curve feature point after the current rotation angle position, and then according to the theoretical transmission ratio values corresponding to the two base points and the deviation between the current rotation angle and the base point rotation angle, the instantaneous theoretical transmission ratio at the current position is calculated through weighted interpolation, the rotation angle increment of the active non-circular gear is multiplied by the instantaneous theoretical transmission ratio, and the result is added to the initial theoretical rotation angle value of the driven non-circular gear to obtain the real-time theoretical rotation angle value of the driven non-circular gear, wherein in the interval in which the change rate of the pitch curve curvature is greater than the preset threshold, the weight coefficient of the interpolation calculation dynamically deviates to the side with a greater change rate of the curvature.

5. The system for real-time error compensation and synchronization control of the non-circular gear transmission of the intermittent paper feed mechanism according to claim 3, wherein, When the non-circular gear engagement error coupling analysis is performed, the controller synchronizes the pitch curve actual rotation angle difference signal and the actual displacement signal of the paper feeding execution mechanism on the time axis according to the rotation angle position of the active non-circular gear; The periodic variation characteristics of the pitch curve engagement error and the paper feeding displacement error during one rotation of the active non-circular gear are extracted, and the main period and the harmonic components of the error variation are identified, wherein the main period is consistent with the engagement period of the non-circular gear; According to the closed characteristic of the pitch curve of the non-circular gear, the pitch curve engagement error and the paper feeding displacement error in one engagement period are decomposed into a systematic error component related to the pitch curve profile and a random error component related to the engagement gap and elastic deformation, a compensation algorithm based on the inverse solution of the pitch curve is adopted for the systematic error component, and an adaptive filtering algorithm is adopted for the random error component, and finally the results of the two algorithms are superimposed to obtain the rotation angle compensation amount of the active non-circular gear.

6. The system for real-time error compensation and synchronization control of the non-circular gear transmission of the intermittent paper feed mechanism according to claim 5, wherein, The controller takes the rotation angle position signal of the driving non-circular gear as the synchronous reference axis, the scale division of the reference axis corresponds to the closed period of the driving non-circular gear, and one complete period corresponds to one complete period of the gear curve; The controller is internally provided with a rotation angle-time mapping table, which pre-stores the theoretical time stamps corresponding to different rotation angle positions of the driving non-circular gear, the time synchronization deviation value is calculated by comparing the collection time stamps of the actual rotation angle difference signal and the actual displacement signal with the theoretical time stamps in the mapping table, and the sampling points of the two signals are dynamically aligned according to the deviation value, so that the gear curve engagement error and the paper feeding displacement error at the same rotation angle position can be accurately associated, and the synchronization accuracy at the long axis and short axis end positions of the driving non-circular gear is set to be higher than that at other positions; When the controller extracts the periodic variation characteristics of the gear curve engagement error and the paper feeding displacement error during one rotation of the driving non-circular gear, a segmented period extraction method based on gear curve feature points is adopted to identify the start and end points of the closed period of the driving non-circular gear, and the maximum curvature radius point of the gear curve is taken as the start point of the period, so that the whole rotation process is divided into a plurality of characteristic segments corresponding to the change of the gear curve profile, and the length of each characteristic segment is dynamically adjusted according to the change rate of the curvature radius of the gear curve, and the characteristic segments in the regions with large change rate of curvature are divided more finely. The error signals in each characteristic segment are independently analyzed to extract the local period components in each characteristic segment, and then the local period components are coupled with the whole period to finally identify the main period and harmonic components of the error variation, wherein the extraction weight of the main period is inclined to the characteristic segments with large change rate of curvature of the gear curve.

7. The system for real-time error compensation and synchronization control of the non-circular gear transmission of the intermittent paper feed mechanism according to claim 6, wherein, When the controller decomposes the error components according to the closed characteristics of the non-circular gear curve, the pre-stored gear curve profile data of the driving non-circular gear and the driven non-circular gear are called, the theoretical engagement gap is calculated through the gear curve profile comparison algorithm, and the theoretical engagement gap is taken as the basic threshold of the systematic error component; For the gear curve engagement error, the part of the error value that is consistent with the deviation trend of the gear curve profile data and has a regular change in amplitude with the rotation angle position is determined as the systematic error component, and the part of the error value that exceeds the range of the theoretical engagement gap and has no obvious change is determined as the random error component; For the paper feeding displacement error, the displacement error part that is linearly related to the change of the gear curve profile is separated as the systematic error component through the establishment of the gear curve profile-displacement transfer function, and the remaining part is combined with the output torque fluctuation data of the driving motor to further decompose the random error component, wherein the decomposition process of the systematic error component needs to introduce the closed constraint condition of the gear curve, and the integral sum of the systematic error component in one period is zero. The compensation algorithm based on the inverse solution of the pitch curve is used to compensate the system error component by calling the inverse solution model of the pitch curve of the non-circular gear, which can inversely calculate the profile parameters of the driving non-circular gear that need to be corrected according to the current identified system error component; the controller calculates the compensation coefficient of the driving non-circular gear at each angular position according to the correction amount of the pitch curve profile parameter, and the compensation coefficient increases with the increase of the curvature radius of the pitch curve and decreases with the decrease of the curvature radius of the pitch curve; The adaptive filtering algorithm is used to compensate the random error component, and a variable step size filtering strategy matching the meshing frequency of the non-circular gear is adopted, the size of the filtering window is dynamically adjusted according to the angular position of the driving non-circular gear, a narrow window filtering is used in the area where the pitch curve meshing frequency is higher than the preset threshold, a wide window filtering is used in the area where the meshing frequency is lower than the preset threshold, and the filtering coefficient is set to be positively correlated with the real-time meshing gap of the driving non-circular gear and the driven non-circular gear; the final angular compensation value is obtained by superimposing the compensation value of the system error component and the filtering result of the random error component according to a fixed weight of 7:3, and the weight of the system error component is higher.

8. The system for real-time error compensation and synchronization control of the non-circular gear transmission of the intermittent paper feed mechanism according to claim 3, wherein, When generating the corrected motor control signal, the controller dynamically allocates the angular compensation value according to the current pitch curve position of the driving non-circular gear, increases the adjustment weight of the angular compensation value when the meshing point of the driving non-circular gear and the driven non-circular gear is close to the long axis endpoint of the pitch curve, and reduces the adjustment weight of the angular compensation value when the meshing point is close to the short axis endpoint of the pitch curve, so as to adapt to the difference in error sensitivity of the non-circular gear at different meshing positions. After receiving the corrected motor control signal, the non-circular gear driving module in the servo driver adjusts the dynamic response characteristics of the output current in real time according to the pitch curve parameters and the current angular position of the driving non-circular gear, and automatically increases the proportional gain and integral time constant of the current loop in the area where the small curvature radius of the pitch curve leads to sudden change of the load torque.

9. The system for real-time error compensation and synchronization control of the non-circular gear transmission of the intermittent paper feed mechanism according to claim 8, wherein, When the controller dynamically allocates the angular compensation value according to the current pitch curve position of the driving non-circular gear, the pre-stored pitch curve profile data of the driving non-circular gear is called to identify the long axis endpoint, the short axis endpoint and the feature inflection points of the pitch curve, and the pitch curve is divided into multiple meshing areas corresponding to the profile change, and the boundary points of each meshing area correspond to the extreme points of the pitch curve curvature; When the meshing point is in the area where the long axis endpoint is located, the controller sets the adjustment weight of the angular compensation value to the highest, and the weight value gradually decreases as the meshing point moves towards the short axis endpoint, and the decreasing trend is consistent with the decreasing trend of the pitch curve curvature radius; When the meshing point is in the area where the short axis endpoint is located, the adjustment weight remains the lowest, and when the meshing point passes through the short axis endpoint, the weight temporary storage mechanism is triggered to keep the compensation value stable at this position; at the same time, the controller tracks the angular change rate of the driving non-circular gear in real time, and increases the adjustment weight to compensate the dynamic transmission error when the sudden change of the angular change rate is detected, and restores to the original weight value after the sudden change ends.

10. The system for real-time error compensation and synchronization control of the non-circular gear transmission of the intermittent paper feed mechanism according to claim 9, wherein, The non-circular gear drive module inside the servo driver pre-stores the correspondence data of the curvature radius of the active non-circular gear pitch curve and the load characteristic, which records the theoretical load state and the reference value of the current loop control parameter corresponding to different angular positions; When receiving the corrected motor control signal, the drive module determines the curvature radius range of the current pitch curve area according to the current angular position of the active non-circular gear, and if it is detected that the curvature radius is in a smaller interval, the control parameters of the current loop are automatically adjusted: the proportional gain is increased to improve the response speed, and the integral time constant is prolonged to enhance the anti-load disturbance ability, and the parameter adjustment amplitude increases with the decrease of the curvature radius; When the curvature radius is in a larger interval, the drive module keeps the current loop parameters as the reference value, and enables the load feedforward compensation function, and outputs the current compensation signal in advance according to the pre-stored theoretical load characteristic data, and the output of the compensation signal is synchronized with the angular position of the active non-circular gear; When the meshing point enters another area from one pitch curve area, the drive module adjusts the current loop parameters through a smooth transition algorithm to avoid motor output fluctuations caused by parameter mutations, and the transition process matches the change rate of the pitch curve profile.

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