A multi-mode variable frequency energy-saving drive control system for UV flatbed printer

Abstract

The present application relates to printing equipment energy saving control technical field, disclose a kind of UV flatbed printer multi-mode variable frequency energy-saving drive control system, including host computer, DC bus, power module, servo driver, inverter, servo motor, printing car, curing lamp array and communication bus.The present application enters power generation state when servo motor is in the deceleration action of printing car execution, servo motor converts rotor kinetic energy into regenerative power and along servo driver reverse injection DC bus, inverter will regenerative power be introduced to curing lamp array;Host computer calculates target total energy and generates control instruction compared with first threshold value, servo driver receives control instruction and adjusts speed gain and torque limit to establish high bandwidth response state or low frequency following state;Power module receives compensation power to DC bus and carries out dynamic power compensation, inverter obtains drive duty cycle in combination with target output voltage and real-time bus voltage to adjust the on-pulse width of curing lamp array.

Description

Technical Field

[0001] This invention relates to the field of energy-saving control technology for printing equipment, specifically a multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer. Background Technology

[0002] When a UV flatbed printer is printing, a servo system drives the print carriage to perform reciprocating linear motion within the print area. A curing lamp array mounted on the print carriage performs UV curing on the ejected ink. As the print carriage changes direction at both ends, it accelerates and decelerates. During deceleration, the servo motor enters a regenerative braking state to generate regenerative electrical energy.

[0003] Existing technologies for handling regenerated electrical energy connect a braking resistor to the DC bus side, dissipating the energy through resistor heating. For servo motor drive control, the control system sends fixed speed gain and torque limit parameters to the servo driver, ensuring the motor maintains a single response state. The drive circuit for the curing lamp array supplies power to the light-emitting devices according to a fixed output reference, with all consumed electrical energy supplied by the main power grid.

[0004] Using resistors to dissipate electrical energy results in low system energy utilization and unnecessary energy loss. Maintaining fixed control parameters in different ink-consuming areas is insufficient to withstand reaction force disturbances under heavy inkjet conditions, and triggers mechanical control loop resonance under light loads. When a regenerative energy feedback mechanism is introduced, the injected energy causes dynamic fluctuations in the DC bus voltage. These voltage fluctuations cause a shift in the transient input power of the curing lamp array, resulting in uneven light radiation energy received per unit area and reduced photocuring quality. Summary of the Invention

[0005] The technical problem solved by this invention is that the regenerative electrical energy generated by the servo motor braking during the reciprocating printing process of a UV flatbed printer cannot be recovered and utilized, and energy is wasted by relying solely on resistance heat dissipation; the fixed drive parameters of the printing carriage when running in different ink consumption areas cause mechanical resonance or energy loss; when a braking energy feedback mechanism is introduced, the dynamic fluctuation of the DC bus voltage causes the output light power of the curing lamp array to deviate, affecting the quality of photocuring.

[0006] To solve the technical problem, the present invention provides the following technical solution:

[0007] This invention provides a multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer, including a host computer, a DC bus, a power module, a servo driver, a converter, a servo motor, a printing carriage, a curing lamp array, and a communication bus.

[0008] The DC bus connects the power module, servo driver, and converter; the servo driver connects to the servo motor, and the servo motor drives the printing carriage; the converter connects to the curing lamp array; the host computer connects to the communication bus, and the power module, servo driver, and converter are all connected in parallel to the communication bus.

[0009] The host computer reads image data, generates control commands, deceleration and acceleration, and compensation power. The host computer sends control commands and deceleration and acceleration to the servo driver through the communication bus. The host computer sets the feedforward buck trigger threshold and sends the feedforward buck trigger threshold and compensation power to the power module through the communication bus.

[0010] When the printing carriage decelerates, the servo motor enters the power generation state. The servo motor converts the rotor kinetic energy into regenerative electrical energy and injects it into the DC bus in reverse along the servo driver. The converter directs the regenerative electrical energy to the curing lamp array.

[0011] The DC bus is connected in parallel with a hardware protection module including a voltage Hall sensor, a hardware protection logic circuit, a braking chopper circuit, and a bleeder resistor. The voltage Hall sensor is connected to the hardware protection logic circuit, which is connected to the control terminal of the braking chopper circuit. The output terminal of the braking chopper circuit is connected in series with the bleeder resistor. The hardware protection logic circuit determines the conduction state of the braking chopper circuit based on the signal fed back by the voltage Hall sensor, thereby bleeding regenerated energy.

[0012] The power module uses a PWM active rectifier with controllable duty cycle output characteristics, and the converter is a DC-DC buck chopper converter; the power module receives the feedforward buck trigger threshold reduction to perform bus voltage pre-adjustment on the output duty cycle of the DC bus; the power module receives compensation power to dynamically replenish the DC bus.

[0013] The servo driver integrates a microcontroller, a speed gain register, and a torque limit register. Control commands include high-density commands and economic commands. When the host computer sends a high-density command to the servo driver, the microcontroller writes the target gain value to the speed gain register and the peak current limit value to the torque limit register to establish a high-bandwidth response state. When the host computer sends an economic command to the servo driver, the microcontroller writes the attenuation gain value to the speed gain register and the clamping current limit value to the torque limit register to establish a low-frequency following state.

[0014] The host computer reads the coordinates of the printing vehicle and determines that the printing vehicle has entered the deceleration zone. The host computer calculates the equivalent average deceleration acceleration based on the current running speed and the deceleration buffer distance constant. The host computer also calculates the peak deceleration acceleration based on the smooth transition coefficient. The host computer writes the equivalent average deceleration acceleration and the peak deceleration acceleration into the internal motion planning control block. The host computer extracts the equivalent average deceleration acceleration and the peak deceleration acceleration latched by the motion planning control block to generate a nonlinear deceleration model. The host computer then sends the deceleration acceleration to the servo driver based on the nonlinear deceleration model.

[0015] The host computer divides the two-dimensional spatial coordinate system into a matrix-arranged prediction grid according to a fixed size step; the host computer extracts the set of pixels inside the prediction grid and extracts the ink droplet density and pixel area of ​​each individual pixel; the host computer calculates the total target energy corresponding to the prediction grid by combining the photosensitive response constant; the host computer compares the total target energy with the first threshold input comparator logic unit and generates control commands.

[0016] The host computer extracts transient deceleration and acceleration to construct transient regenerative power; the host computer sets rated constant power based on the target total energy; the host computer obtains transient demand power based on real-time command speed and rated constant power; the host computer uses its internally integrated microprocessor to compare transient demand power and transient regenerative power, the microprocessor calculates the difference to obtain compensation power and sends the compensation power to the power module.

[0017] The host computer calls the internally integrated numerical integration calculation module to perform integral calculation on the transient regenerative power to obtain the predicted total regenerative energy; the host computer combines the predicted total regenerative energy and the expected dynamic total energy consumption to obtain the net charging energy; the host computer obtains the target bus voltage based on the net charging energy and physical capacitance, and sets the target bus voltage as the feedforward step-down trigger threshold of the DC bus.

[0018] The host computer extracts the real-time command speed and the rated constant power dynamic decay to generate the transient demand power; the host computer calculates the transient demand power into the target drive current, and obtains the target output voltage based on the target drive current; the host computer combines the target output voltage and the real-time bus voltage to obtain the drive duty cycle; the host computer sends the drive duty cycle to the converter, and the converter adjusts the conduction pulse width of the solidified lamp array according to the drive duty cycle.

[0019] The host computer calls the internally integrated accumulator module to obtain the average theoretical drive voltage by combining the real-time bus voltage and the drive duty cycle; the host computer obtains the estimated operating current based on the average theoretical drive voltage; the host computer obtains the equivalent power by combining the average theoretical drive voltage and the estimated operating current; the host computer calculates the transient optical power by combining the equivalent electrical power and the photoelectric conversion efficiency; and the host computer accumulates the transient optical power to obtain the equivalent cumulative total optical radiation energy.

[0020] This invention provides a multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer. It has the following beneficial effects:

[0021] 1. This invention enables the servo motor to enter the power generation state when the printing carriage performs deceleration. The servo motor converts the rotor kinetic energy into regenerative electrical energy and injects it into the DC bus in reverse. The converter directs the regenerative electrical energy to the curing lamp array for consumption. The system recovers the energy generated by the motor braking, reducing the energy waste caused by resistive heat dissipation.

[0022] 2. This invention uses a host computer to calculate and predict the total target energy corresponding to the grid by combining the photosensitive response constant, and compares the total target energy with a first threshold to generate a high-density command or an economic command. The servo driver receives the control command and adjusts the speed gain and torque limit. The system establishes a high-bandwidth response state or a low-frequency following state based on the ink consumption level, reducing the power consumption during light-load operation and preventing mechanical resonance caused by fixed control parameters.

[0023] 3. This invention obtains compensation power by comparing transient demand power and transient regenerated power through a host computer. The power supply module receives the compensation power and supplies power to the DC bus. The converter combines the target output voltage and the real-time bus voltage to obtain the driving duty cycle and adjust the conduction pulse width of the curing lamp array. The system cancels the deviation caused by the dynamic fluctuation of the DC bus voltage and maintains the physical balance of the light radiation energy of the curing lamp array. Attached Figure Description

[0024] Figure 1 The structural framework diagram of the multi-mode frequency conversion energy-saving drive control system for UV flatbed printers provided by the present invention is shown.

[0025] Figure 2 This is a flowchart illustrating the multi-mode frequency conversion energy-saving drive control method for UV flatbed printers provided by the present invention.

[0026] Figure 3 This is a flowchart illustrating the image data parsing, predictive grid division, and target total energy calculation processes in this invention.

[0027] Figure 4 This is a schematic diagram of the process for switching the servo drive state based on the target total energy in this invention.

[0028] Figure 5 This is a flowchart illustrating the deceleration interval identification, deceleration grid queue generation, and nonlinear deceleration trajectory planning processes in this invention.

[0029] Figure 6 This is a flowchart illustrating the process of calculating transient regenerative power, transient demand power, and generating a power compensation feedforward data table in this invention.

[0030] Figure 7This is a flowchart illustrating the target bus voltage generation, DC bus pre-adjustment, curing lamp array drive duty cycle adjustment, and hardware protection processes in this invention.

[0031] Figure 8 This is a comparison diagram of the dynamic changes of the DC bus voltage in the deceleration and braking range of the present invention. Detailed Implementation

[0032] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] See Figure 1 This invention provides a multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer, including a host computer and a DC bus. The DC bus connects a power module, a servo driver, and a converter. The power module uses a PWM active rectifier with controllable duty cycle output characteristics. The converter is a DC-DC buck converter. The power module is connected to an external AC power grid and converts and transmits electrical energy to the DC bus. The servo driver is connected in parallel to the DC bus to extract electrical energy from the DC bus. The converter is connected in parallel to the DC bus to extract electrical energy from the DC bus. The host computer sets the feedforward buck trigger threshold of the DC bus and sends it to the power module. The DC bus collects the electrical energy transmitted by the power module and the regenerated electrical energy flowing inside the system.

[0034] The servo driver connects to the servo motor, which in turn drives the printing carriage. The servo motor drives the printing carriage to perform reciprocating motion and deceleration along the printing surface. The converter connects to the curing lamp array, which adjusts the conduction pulse width of the curing lamp array according to the modulation duty cycle. The curing lamp array moves synchronously with the printing carriage, consuming electrical energy to perform the photocuring operation. When the printing carriage decelerates, the servo motor enters the generator state, converting the rotor kinetic energy into regenerative electrical energy and injecting it into the DC bus in reverse along the servo driver. The converter then directs the regenerative electrical energy to the curing lamp array.

[0035] A hardware protection module, comprising a voltage Hall sensor, hardware protection logic circuit, braking chopper circuit, and bleeder resistor, is also connected in parallel on the DC bus. The voltage Hall sensor is connected to the hardware protection logic circuit, which in turn is connected to the control terminal of the braking chopper circuit. The output terminal of the braking chopper circuit is connected in series with the bleeder resistor. The hardware protection logic circuit determines the conduction state of the braking chopper circuit based on the signal fed back from the voltage Hall sensor, in order to bleed excess regenerative energy.

[0036] The host computer is connected to the communication bus. The power module, servo driver, and converter are all connected in parallel to the communication bus. The host computer reads image data and generates control commands, deceleration acceleration, and compensation power based on the image data. The host computer sends control commands and deceleration acceleration to the servo driver through the communication bus. The host computer also sends the feedforward buck trigger threshold and compensation power to the power module through the communication bus. The servo driver receives the control commands and adjusts the speed gain and torque limit. The servo driver receives the deceleration acceleration and generates a nonlinear deceleration trajectory. The power module receives the feedforward buck trigger threshold and actively reduces the output duty cycle to the DC bus to perform bus voltage pre-adjustment. It also receives the compensation power to dynamically replenish the DC bus. The communication bus establishes a communication data frame transmission and reception channel. The control system relies on the communication bus to integrate all the underlying control nodes and realize closed-loop interleaving of energy flow.

[0037] See Figure 2 Based on the aforementioned multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer, this invention further provides a multi-mode frequency conversion energy-saving drive control method for a UV flatbed printer, which includes the following steps:

[0038] S100: The host computer reads the image data to be printed and performs data parsing to establish a two-dimensional spatial coordinate system for the printing area. The host computer divides the two-dimensional spatial coordinate system into a matrix-arranged prediction grid according to a fixed size step. The host computer extracts the set of pixels inside the prediction grid and extracts the ink droplet density and pixel area of ​​a single pixel. The host computer calculates the total target energy corresponding to the prediction grid by combining the photosensitive reaction constant.

[0039] S200: The host computer extracts the total target energy and compares it with a preset first threshold. When the total target energy is determined to be greater than the first threshold and the preset spatial hysteresis condition is met, the host computer sends a high-density command to the servo driver connected to the DC bus. The servo driver receives the high-density command, increases the speed gain, and expands the torque limit to establish a high-bandwidth response state. When the total target energy is determined to be less than or equal to the first threshold and the preset spatial hysteresis condition is met, the host computer sends an economic command to the servo driver. The servo driver receives the economic command, decreases the speed gain, and compresses the torque limit to establish a low-frequency following state.

[0040] The S300 system reads the coordinates of the printing carriage, which carries the printhead and moves back and forth within the printing area, and determines that the carriage has entered the deceleration zone where the extreme coordinates at both ends are located. The system retrieves the adjacent prediction grids in front of the carriage and extracts the target total energy corresponding to the adjacent prediction grids. The system uses the current running speed and deceleration buffer distance to calculate the deceleration acceleration of the carriage when it performs deceleration. It also sets the rated constant power based on the target total energy as a comparison benchmark for building the subsequent power compensation mechanism. The system sends the deceleration acceleration to the servo driver through the communication bus. The servo driver generates a nonlinear deceleration trajectory according to the deceleration acceleration and drives the servo motor to perform braking action.

[0041] S400: The host computer extracts the transient deceleration acceleration generated by the printing carriage following the deceleration trajectory and uses the transient deceleration acceleration to construct the transient regenerative power of the servo motor rotor kinetic energy converted to the DC bus side. The host computer combines the real-time speed to generate the transient demand power and compares the transient demand power with the transient regenerative power. The host computer calculates the difference to obtain the compensation power and sends the compensation power to the power module.

[0042] Before the printing carriage enters the deceleration zone, the host computer calculates and sends the target bus voltage (i.e., the feedforward buck trigger threshold) of the DC bus. Based on this, the power module actively reduces the output duty cycle to the DC bus to reserve energy storage space. When the printing carriage enters the deceleration zone, it performs a deceleration action, which causes the servo motor to enter the generator state. The rotor kinetic energy of the servo motor is converted into regenerative electrical energy and injected into the DC bus, causing the transient voltage of the DC bus to rise from the starting point of the target bus voltage. During this period, the power module outputs supplementary electrical energy to the DC bus according to the time sequence and the calculated compensation power. The converter obtains the real-time bus voltage reflecting the power balance state of the system in real time and generates a modulation duty cycle that is inversely proportional to the real-time bus voltage. The converter diverts the collected electrical energy to the curing lamp array and adjusts the conduction pulse width of the curing lamp array according to the modulation duty cycle. The curing lamp array consumes the diverted electrical energy to complete the photocuring operation of the adjacent predicted grid.

[0043] The following section provides a detailed explanation of the specific steps involved in the control method.

[0044] See Figure 3 Step S100 includes the following sub-steps:

[0045] S101, the host computer receives raster-formatted image data via a network interface. The image data records the dot matrix information of ink droplets and color channel information. The host computer calls a decoding program to unpack the image data. The host computer extracts the dot matrix information and converts it into a pixel feature matrix that is easy to perform mathematical calculations.

[0046] S102, the host computer sends a zero-finding control signal to the servo driver. The servo driver drives the servo motor to move the printing carriage to find the initial boundary. When the printing carriage touches the mechanical boundary, causing the servo motor to output electromagnetic torque that reaches the preset anti-collision resistance threshold, or triggering the underlying photoelectric limit switch, the servo driver reads the scale value of the encoder inside the servo motor and feeds the scale value back to the host computer. The host computer receives the scale value and anchors it as the reference zero point. The host computer retrieves the pre-stored platform width constant and platform length constant. The host computer uses the platform width constant to establish the maximum coordinate extreme value of the horizontal coordinate axis. The host computer uses the platform length constant to establish the maximum coordinate extreme value of the vertical coordinate axis. The host computer orthogonally combines the horizontal and vertical coordinate axes with the reference zero point to finally generate a two-dimensional spatial coordinate system covering the entire printing area. The host computer maps the pixel feature matrix to the corresponding coordinate nodes inside the two-dimensional spatial coordinate system.

[0047] S103, the host computer retrieves the pre-stored horizontal segmentation step size and vertical segmentation step size. The host computer performs equidistant segmentation along the horizontal coordinate axis according to the horizontal segmentation step size, and the host computer performs equidistant segmentation along the vertical coordinate axis according to the vertical segmentation step size. The horizontal segmentation line and the vertical segmentation line intersect each other perpendicularly and generate a matrix-arranged prediction grid within the two-dimensional spatial coordinate system. The matrix arrangement is equivalent to an array structure with interwoven rows and columns.

[0048] S104, the host computer obtains the boundary coordinate range of the prediction grid, the host computer traverses the coordinate nodes existing inside the pixel feature matrix, the host computer compares the coordinate nodes with the boundary coordinate range, when it is determined that the coordinate node falls within the boundary coordinate range, the host computer determines that the pixel corresponding to the coordinate node belongs to the current comparison prediction grid, the host computer packages and classifies all pixels falling within the same prediction grid and generates a pixel set.

[0049] S105, the host computer reads the pixel set, parses the printing process parameters carried within the pixel set, extracts the required ink volume for different color channels from the printing process parameters, converts the required ink volume into ink droplet density, retrieves the resolution parameters of the image data, and directly calculates the physical pixel area occupied by a single pixel using these resolution parameters. Ink droplet density represents the mass of ink ejected per unit area, and pixel area represents the size of the space occupied by a single pixel in a two-dimensional coordinate system. The host computer stores the ink droplet density and pixel area in a buffer register for subsequent mathematical operations.

[0050] S106, the host computer retrieves the ink droplet density and pixel area from the cache register, the host computer counts the total number of pixels in the pixel set, and the host computer establishes a loop accumulation variable to wait for the execution of mathematical multiplication and addition operations.

[0051] S107, the host computer reads the photosensitive reaction parameters pre-stored in the system file. The photosensitive reaction parameters record the energy constant required for the ink to undergo photochemical cross-linking reaction. The energy constant represents the amount of light radiation energy received by a unit mass of ink to complete curing.

[0052] S108, the host computer multiplies the ink droplet density and pixel area to obtain the ink mass corresponding to a single pixel. The host computer then sums the ink masses corresponding to all pixels within the prediction grid using the total number of pixels to obtain the total ink mass of the prediction grid. Finally, the host computer multiplies the total ink mass by the energy constant to obtain the total target energy corresponding to the prediction grid. The formula is as follows:

[0053] ;

[0054] In the formula, Represents the total energy of the target; Represents ink droplet density; Represents pixel area; Represents the total number of pixels; Represents the energy constant.

[0055] S109, the host computer writes the total target energy into the memory address for storage and establishes the mapping relationship between the total target energy and the prediction grid. The host computer traverses all the prediction grids in the two-dimensional spatial coordinate system in the order of matrix arrangement. The host computer performs mathematical multiplication and addition operations in a loop until the total target energy corresponding to each prediction grid is calculated.

[0056] See Figure 4 Step S200 includes the following sub-steps:

[0057] S201, the host computer retrieves the target total energy stored in the memory address through the memory address pointer, and the host computer reads the system parameter file to obtain the preset first threshold. The first threshold represents the scale parameter that distinguishes the ink consumption of different areas of the print area.

[0058] In S202, the host computer uses its integrated microprocessor to perform numerical comparison calculations. The host computer inputs the target total energy and a first threshold into the comparator logic unit. When the microprocessor determines that the target total energy is greater than the first threshold, and that multiple consecutive prediction grids exceed this threshold to meet the preset spatial hysteresis condition, the host computer determines that the prediction grid currently in the comparison state and the subsequent contiguous area belong to a high-ink-consumption area. The host computer then calls internal control library functions to generate a high-density instruction. The system relies on the spatial hysteresis condition to avoid high-frequency switching of underlying parameters that could cause mechanical control loop resonance when crossing small grids. The high-density instruction corresponds to the motor drive parameter setting requirements under heavy-duty inkjet conditions.

[0059] S203, when the microprocessor determines that the total energy of the target is less than or equal to the first threshold and meets the preset spatial hysteresis condition, the host computer determines that the prediction grid and subsequent contiguous areas currently in the comparison state belong to the low ink consumption area. The host computer calls the internal control library function to generate an economic instruction. The economic instruction corresponds to the motor energy-saving drive parameter setting requirements under light-load inkjet conditions.

[0060] S204, the host computer performs packetization operation on high-density instructions or economic instructions according to the data frame format supported by the communication bus. The host computer writes the high-density instructions or economic instructions into the process data object. The host computer pushes the process data object loaded with high-density instructions or economic instructions into the transmission queue to wait for the communication bus cycle to trigger the execution of the distribution operation.

[0061] S205: The host computer sends a data frame containing high-density instructions to the servo driver via the communication bus. The servo driver receives the data frame using its internal communication interface and performs unpacking operations to extract the high-density instructions. The servo driver integrates a microcontroller and multiple sets of control registers. The control registers are specifically divided into a speed gain register that stores the proportional-integral parameters of the control loop and a torque limit register that controls the peak output current.

[0062] S206: The servo driver parses high-density instructions to obtain the target gain value to be adjusted. The microcontroller calls the built-in first-order low-pass filter algorithm or ramp function to smoothly write the target gain value into the speed gain register. Within the set transition period, it gradually approaches the target value to complete the speed gain adjustment operation, avoiding sudden changes in motor torque caused by parameter step jumps. The speed gain adjustment increases the position error compensation amplitude of the servo motor feedback and shortens the speed loop settling time.

[0063] S207, the servo driver parses the high-density instruction to obtain the corresponding expanded target current limit value, the microcontroller writes the peak current limit value to the torque limit register to complete the torque limit expansion operation, the torque limit expansion releases the current clamping state of the servo motor in the heavy load acceleration stage, the servo motor obtains sufficient electromagnetic torque output capability to resist the micro-reaction force disturbance caused by the high frequency action of the piezoelectric ceramic when the printing carriage is fully open for high-frequency inkjet printing, and maintains high-precision trajectory rigidity.

[0064] After the S208 servo driver completes the speed gain increase and torque limit expansion, it establishes a high bandwidth response state. In the high bandwidth response state, the lag error of the control system in following the position command pulse is reduced, and the servo motor drives the printing carriage strictly according to the planned curve to meet the trajectory following accuracy requirements under heavy inkjet conditions.

[0065] S209, the host computer pushes the data frame containing the economic instructions into the transmission queue of the communication bus. The host computer sends the data frame to the servo driver through the communication bus. The servo driver uses its internal communication interface to receive the data frame and performs unpacking operation to extract the economic instructions from the data frame.

[0066] S210: The servo driver parses the economic instruction to obtain the target gain value to be lowered as required. The microcontroller calls the ramp function to write the attenuation gain value to the speed gain register. The original data is gradually overwritten according to the set slope to complete the speed gain reduction operation. The speed gain reduction extends the settling time of the control loop and reduces the drive rigidity of the servo motor. The reduced drive rigidity eliminates the small oscillations generated by the servo motor under light-load inkjet conditions.

[0067] S211, the servo driver parses the economic instruction to obtain the corresponding compression target current limit value, the microcontroller writes the clamp current limit value to the torque limit register to complete the torque limit compression operation. The torque limit compression causes the stator current amplitude of the servo motor to be clamped during operation. The clamp constraint directly limits the peak electromagnetic torque output by the servo motor, thereby reducing power consumption.

[0068] In S212, after the servo driver completes speed gain reduction and torque limiting compression, it establishes a low-frequency following state. In this state, the microcontroller lowers the pulse-width modulation (PWM) carrier frequency of the internal inverter bridge. This reduction decreases the number of switching operations of the power devices within the inverter bridge, thereby reducing switching losses caused by high-frequency motor chopping. The control system achieves energy saving by relying on this low-frequency following state when the predicted grid is in a low-ink-consumption region. To prevent motor jitter caused by sudden changes in the current loop poles due to the dynamic reduction of the PWM carrier frequency, the microcontroller automatically switches the corresponding current loop low-pass filter parameters and dead-time compensation coefficient within the same control cycle as the carrier frequency reduction, achieving a smooth transition of the underlying control logic.

[0069] See Figure 5 Step S300 includes the following sub-steps:

[0070] S301, the host computer sends a position query message to the servo driver via the communication bus. The servo driver parses the position query message and reads the rotor mechanical angle fed back by the absolute encoder inside the servo motor. The servo driver uses the internal microcontroller to multiply the rotor mechanical angle by the mechanical transmission ratio to convert it into the real-time running coordinates of the printing carriage in the two-dimensional spatial coordinate system. The servo driver packages the real-time running coordinates into a response data frame and uploads it to the host computer via the communication bus. The host computer receives the response data frame and stores the real-time running coordinates in the buffer area to wait for position comparison.

[0071] S302, the host computer retrieves the pre-set deceleration buffer distance constant. It extracts the extreme coordinates at both ends of the horizontal axis of the two-dimensional spatial coordinate system. Using these extreme coordinates, the host computer shifts the deceleration buffer distance constant towards the center point of the two-dimensional spatial coordinate system, generating two symmetrically distributed deceleration intervals. The host computer reads the real-time running coordinates from the buffer area and determines the trigger conditions for the real-time running coordinates to fall within the two deceleration intervals. Based on the capacity of the DC bus energy storage capacitor, the target feedforward voltage reduction amplitude, and the maximum permissible power of the power module's inverter feedback to the main grid, the host computer pre-calculates the physical discharge time required for the bus voltage to complete the feedforward voltage reduction. The host computer multiplies this physical discharge time by the current running speed of the printing vehicle and adds a system communication delay constant to establish the look-ahead safety distance for triggering preprocessing. By precisely setting this distance, when the microprocessor determines that the real-time running coordinates have reached the preset look-ahead safety distance ahead of the deceleration interval, the host computer generates a preprocessing trigger signal and performs look-ahead data extraction and trajectory planning operations in advance.

[0072] S303, the host computer reads the real-time running coordinate difference of the printing vehicle in two consecutive communication sampling cycles to calculate the current moving direction of the printing vehicle. Based on the moving direction, the host computer performs spatial index addressing forward, extracts all the predicted grids that fall within the deceleration zone and are continuously arranged along the travel trajectory, calculates the row and column index numbers of these grids, and packages these grids to generate a deceleration grid queue. This deceleration grid queue represents the target working area that the printing vehicle needs to cross and perform photopolymerization operations in sequence during deceleration and braking.

[0073] In step S304, the host computer accesses the data mapping table stored in memory based on the row and column index numbers. The host computer then locates the total target energy corresponding to all predicted grids within the deceleration grid queue. The host computer compares and extracts the maximum total target energy in the queue, using it as the baseline fixed energy threshold for that deceleration interval. The host computer stores and locks this baseline fixed energy threshold in a dedicated feedforward calculation register, using this harsh operating condition as a baseline for reverse engineering the lower limit of energy compensation control.

[0074] S305: The host computer reads the baseline curing energy threshold from the feedforward calculation register via the internal data bus. The host computer extracts the physical length of a single predicted grid in the two-dimensional coordinate system and, combined with the current operating speed of the printing vehicle before entering the deceleration zone, estimates the baseline curing time for the curing lamp array to traverse a single grid at a constant vehicle speed. Photoelectric conversion efficiency characterizes the physical ratio of the electrical energy consumed by the curing lamp array to effective light radiation energy. The host computer calculates the rated constant power for light curing operations that meets the baseline curing energy threshold by dividing the baseline curing time by the photoelectric conversion efficiency, and synchronously stores this rated constant power in the feedforward calculation register for numerical update locking. The formula is as follows:

[0075] ;

[0076] In the formula, Represents rated constant electrical power; Represents the baseline curing energy threshold; The physical length of a single prediction grid; Represents the current running speed; It represents photoelectric conversion efficiency.

[0077] S306: The host computer retrieves the total load mass of the printing carriage and the mechanical transmission efficiency of the transmission mechanism from its internally integrated electromechanical parameter library. The host computer reads the current operating speed uploaded in real-time by the servo driver. When the servo motor enters braking mode, the mechanical kinetic energy of the printing carriage is converted into the rotor kinetic energy of the servo motor through the transmission mechanism, and then converted into regenerative electrical power by the servo motor as a generator. The host computer establishes an equivalent mapping model between regenerative electrical power and mechanical motion parameters, and a forward evolution model between mechanical motion parameters and regenerative electrical power to deduce the actual regenerative electrical energy that the servo motor can provide under a given deceleration trajectory.

[0078] S307: The host computer retrieves the pre-set deceleration buffer distance constant and reads the current operating speed. Using the current operating speed and the deceleration buffer distance constant, the host computer estimates the equivalent average deceleration acceleration required for the printing carriage to complete braking within a set distance. The host computer reads the pre-stored cycloidal trajectory smoothing transition coefficient (this constant is set to 2 based on the cycloidal derivative characteristics). The host computer multiplies the equivalent average deceleration acceleration by this smoothing transition coefficient to deduce the peak deceleration acceleration that the servo motor must provide under the cycloidal trajectory. The formula is as follows:

[0079] ;

[0080] ;

[0081] In the formula, Represents the equivalent average deceleration acceleration; Represents the current running speed; Represents the deceleration buffer distance constant; This represents the peak deceleration acceleration.

[0082] S308: The host computer extracts the maximum peak electromagnetic torque that the servo motor can safely withstand and, combined with the total load mass, deduces the physically permissible safe deceleration limit of the servo motor. The host computer then compares the calculated peak deceleration with the safe deceleration limit.

[0083] If the peak deceleration is determined to be less than or equal to the safe limit deceleration, the host computer determines that the currently set deceleration buffer distance meets the requirements for safe flexible braking. The host computer writes the locked equivalent average deceleration and peak deceleration values ​​into the internal motion planning control block and performs a latching operation on the data. The equivalent average deceleration is retained for calculating the subsequent total deceleration time, while the peak deceleration is used to generate the extreme value of the nonlinear trajectory curve. This judgment logic explicitly eliminates the risk of missing the judgment of the actual mechanical braking peak exceeding the limit due to using only the equivalent average deceleration as a comparison benchmark. It establishes a synchronous trigger association with the current running coordinates, waiting for subsequent links to directly call and generate braking control commands.

[0084] If the peak deceleration is determined to be greater than the safe limit deceleration, the control system determines that conventional flexible deceleration can no longer safely stop the machine within the set distance. The system immediately bypasses the cycloidal trajectory planning logic and directly triggers hardware-level maximum torque emergency braking (dynamic braking) to absorb mechanical kinetic energy to the greatest extent to intercept the current motion. It also issues an over-limit alarm and forcibly interrupts the unsafe trajectory execution logic.

[0085] S309: The host computer retrieves the latched equivalent average deceleration acceleration from the motion planning control block. The host computer extracts the physical limit data of the servo motor's ability to withstand mechanical shock and establishes jerk constraints. Jerk represents the rate of change of acceleration over time. The host computer introduces a smooth transition algorithm to extract the latched peak deceleration acceleration as the core extreme value control parameter of the trajectory curve, constructing a nonlinear deceleration model with continuous derivatives in both the starting and ending phases.

[0086] The S310's host computer generates smooth real-time speed commands using a nonlinear deceleration model. It calculates the total deceleration time by dividing the current operating speed by the equivalent average deceleration acceleration. To eliminate mechanical excitation caused by the printing vehicle's braking, the host computer uses a cycloidal speed planning curve to establish the braking trajectory, ensuring flexible changes in driving torque. The formula is as follows:

[0087] ;

[0088] In the formula, Represents real-time command speed; Represents the current running speed; Represents peak deceleration; This represents the set total deceleration time; This represents the current braking time.

[0089] In S311, the host computer performs discretization interpolation on the real-time command speed according to the control cycle of the communication bus. The host computer packages the periodic position increment generated by interpolation into motion control commands. The host computer writes the motion control commands into the process data object and sends them in advance to the feedforward buffer register of the servo driver for latching, waiting to be called and executed when the printing vehicle triggers the deceleration interval boundary in physical space.

[0090] See Figure 6 Step S400 includes the following sub-steps:

[0091] S401: The host computer extracts real-time command speed from the motion planning control block through the internal data bus. The host computer performs time derivative calculation on the real-time command speed to obtain transient deceleration and acceleration.

[0092] The host computer reads the system settings file to obtain the guide rail friction coefficient. The host computer then multiplies the total load mass, the gravitational acceleration constant, and the guide rail friction coefficient to calculate the total mechanical resistance of the printing carriage.

[0093] S402, the host computer retrieves the pre-stored mechanical transmission efficiency and servo motor power generation efficiency. The host computer multiplies the mechanical transmission efficiency and power generation efficiency to determine the comprehensive energy conversion efficiency. The comprehensive energy conversion efficiency characterizes the retention rate of the printing vehicle's mechanical kinetic energy ultimately converted into DC bus electrical energy.

[0094] S403: The host computer multiplies the absolute value of the transient deceleration acceleration by the total load mass to obtain the total deceleration force required by the printing carriage during braking. The host computer subtracts the total mechanical resistance of the system from the total deceleration force to obtain the actual mechanical load absorbed by the servo motor shaft. The host computer multiplies this mechanical load by the real-time command speed to obtain the mechanical input power of the servo motor. The host computer multiplies the mechanical input power by the overall energy conversion efficiency to construct a transient regenerative power model. The formula is as follows:

[0095] ;

[0096] In the formula, Represents transient regenerative power; Represents the total mass of the load; Represents transient deceleration and acceleration; Represents the total mechanical resistance of the system; Represents real-time command speed; It represents the overall energy conversion efficiency.

[0097] In S404, the host computer compiles the transient regenerative power model into an executable mathematical function, which is then encapsulated in the internal system's control layer call library. The host computer performs discretization by periodically substituting time variables into the mathematical function, obtaining the transient regenerative power values ​​generated by the servo motor at specific time points within the deceleration and braking interval. The host computer establishes a mapping between the calculated time series and the transient regenerative power values, storing the mapping data in an array structure in memory for subsequent power comparison tasks.

[0098] The S405's host computer sequentially reads the transient regenerative power from an array structure in memory via its internal data bus, following a time-series order. It then retrieves the rated constant power previously locked in the feedforward calculation register. Because the printing carriage's speed decreases non-linearly during deceleration, maintaining a constant power would result in excessive accumulated light radiation energy per unit area. The host computer, combining this with the real-time command speed, calculates the transient power demand at each time point (equal to the rated constant power multiplied by the ratio of the real-time command speed to the current operating speed). The host computer then utilizes its integrated microprocessor to perform data alignment and numerical comparison calculations at discrete time points.

[0099] S406: When the microprocessor determines that the transient regenerative power at a certain time point is less than the transient demand power at that time, the host computer determines that the regenerative energy collected on the DC bus side cannot fully meet the dynamic operation requirements of the solidified lamp array. The host computer calls the internally integrated power compensation calculation unit. The power compensation calculation unit subtracts the transient regenerative power at that time point from the transient demand power to calculate the additional transient compensation power that needs to be supplemented by the system power supply. The formula is as follows:

[0100] ;

[0101] In the formula, Represents transient compensation power; Represents rated constant electrical power; Represents real-time command speed; Represents the current running speed; This represents transient regenerative electrical power.

[0102] S407: When the microprocessor determines that the value of the transient regenerative power is greater than or equal to the transient demand power, the host computer determines that the regenerative energy in the current time period is sufficient, and the host computer directly assigns the transient compensation power of the corresponding time node to zero. The host computer writes (enqueues) the calculated total transient compensation power into a dedicated compensation data queue according to the original braking time sequence, waiting for it to be sent.

[0103] In S408, the host computer pre-generates the corresponding power compensation feedforward data table based on the sequence data stored in the compensation data queue. Before the printing vehicle actually triggers the deceleration interval, the host computer sends out the entire power compensation feedforward data table via the communication bus and latches it in the buffer RAM at the bottom layer of the power module. This pre-send mechanism eliminates the interference of real-time bus communication delay during deceleration on the synchronization of transient power compensation.

[0104] In S409, the power module receives and parses the power compensation feedforward data table stored in the buffer RAM. The digital signal processor inside the power module uses this data as a reference for the local voltage control loop. The underlying hardware timer autonomously generates and dynamically adjusts the high-frequency duty cycle of the power switching transistors. The power module precisely injects the main grid's power into the DC bus according to the transient compensation power allowance. The DC bus synchronously aggregates the regenerative power from the servo motor and the compensation power from the power module. This compensation mechanism ensures that the curing lamp array always receives a constant input power matching the target total energy during the nonlinear deceleration phase, avoiding deviations in photocuring quality caused by fluctuations in mechanical deceleration torque.

[0105] See Figure 7 Step S500 includes the following sub-steps:

[0106] S501, the host computer calls the internally integrated numerical integration calculation module to perform time-definite integral calculation on the transient regenerative power model over the entire set deceleration time. The time-definite integral calculation obtains the predicted total regenerative energy that the servo motor will inject into the DC bus side during the nonlinear deceleration phase. The formula is as follows:

[0107] ;

[0108] In the formula, Represents the predicted total renewable energy; This represents the set total deceleration time; Represents transient regenerative power; Represents a time variable.

[0109] S502: The host computer reads the system hardware settings list to obtain the physical capacitance of the energy storage capacitors connected in parallel across the DC bus. The host computer then reads the rated bus voltage of the DC bus under normal power supply conditions. Based on the principle of capacitor energy storage, the host computer constructs an energy conversion balance equation.

[0110] The host computer extracts the rated constant power locked in the feedforward calculation register. Considering that the transient power demand of the curing lamp array decreases linearly with speed, the host computer multiplies the rated constant power by the deceleration buffer distance constant and then divides it by the current operating speed. Through spatial integration, it calculates the expected total dynamic energy consumed by the curing lamp array in the entire deceleration range.

[0111] The host computer subtracts the expected dynamic total energy consumption from the predicted total regeneration energy to calculate the net charging energy expected to be received by the DC bus. When the net charging energy is determined to be greater than zero, the host computer converts this net charging energy into an equivalent electric field energy space that the energy storage capacitor needs to free up, and then calculates the energy based on the capacitor energy formula. The target bus voltage capable of fully absorbing this energy is calculated in reverse. The host computer directly maps this target bus voltage as the feedforward step-down trigger threshold of the DC bus. When the net charging energy is determined to be less than or equal to zero, the host computer determines that no additional energy storage space needs to be reserved for the current DC bus, and directly assigns the target bus voltage to the rated bus voltage. The formula for the reverse calculation of the target bus voltage is as follows:

[0112] ;

[0113] In the formula, Represents the target bus voltage; Represents the rated bus voltage; Represents the predicted total renewable energy; Represents rated constant electrical power; Represents the deceleration buffer distance constant; Represents the current running speed; This represents the physical capacitance of the energy storage capacitor.

[0114] To prevent the servo drive hardware from going offline due to an excessively low calculated target bus voltage, the host computer synchronously retrieves the undervoltage protection safety threshold built into the servo drive. The host computer performs a boundary lower limit comparison on the calculated target bus voltage: when it determines that the target bus voltage is lower than the undervoltage protection safety threshold, the host computer forcibly clamps the target bus voltage to that undervoltage protection safety threshold. The system maintains the weak field excitation capability of the servo motor through the reserved voltage lower limit. The remaining predicted total regenerative energy that cannot be absorbed by the energy storage capacitor is retained until the braking action is triggered and then converted into heat energy by the subsequent braking chopper circuit.

[0115] In S503, the host computer calculates the feedforward buck offset by subtracting the rated bus voltage from the target bus voltage. The host computer encapsulates this feedforward buck offset into a voltage bias control frame and sends it to the power module in advance via the communication bus. The voltage closed-loop controller inside the power module parses the voltage bias control frame, and the power module adjusts the voltage feedback reference of its internal pulse width modulation logic downwards, establishing that the system has entered constant voltage pre-adjustment mode.

[0116] The power module actively reduces the energy injection from the main grid and uses the bidirectional energy flow characteristics of the internal PWM active rectifier to invert and feed excess power from the DC bus back to the main grid, or coordinates with the natural energy consumption of the system's normal operating loads to cause the DC bus voltage to drop smoothly to the target bus voltage. The system completes the pre-construction of the energy buffer space before the physical braking action occurs.

[0117] The S504 system retrieves the ultimate physical withstand voltage of the energy storage capacitors connected in parallel across the DC bus from the host computer. Simultaneously, the host computer extracts the safe breakdown voltage of the power devices in the inverter bridge within the servo driver. The host computer selects the lower of the two values ​​and multiplies it by a safety factor to calculate the bus overvoltage trigger threshold. The host computer writes the bus overvoltage trigger threshold into the threshold register of the hardware protection logic circuit. When subsequent absorption of regenerated energy causes an abnormal voltage increase, the hardware protection logic circuit triggers the discharge protection action based on this threshold.

[0118] In the S505, when the real-time running coordinates of the printing carriage trigger the preset deceleration interval boundary, the servo driver matches the coordinate position pre-locked in its internal feedforward buffer register and autonomously triggers an internal braking command. The servo motor switches to generator operation mode, and the servo driver maintains closed-loop control of position and speed. The power switching transistors of its internal inverter bridge actively perform four-quadrant chopping according to the pulse width modulation signal, actively rectifying / inverting the regenerated AC power output by the servo motor and injecting it into the DC bus. The energy storage capacitors connected in parallel across the DC bus absorb the regenerated charge, and the bus voltage begins to rise from the target bus voltage starting point established by the feedforward step-down mechanism. Simultaneously, the curing lamp array continuously draws power from the DC bus to perform photocuring operations, consuming the energy accumulated on the DC bus side.

[0119] During the synchronous operation of braking energy feedback and photopolymerization, the host computer maintains high-frequency distributed clock synchronization with the underlying control node. The digital signal processor inside the power module synchronizes the braking timing of the printing vehicle based on the local high-frequency timer interrupt and directly reads the transient compensation power from the local buffer RAM according to the time sequence to perform high-speed local closed-loop control.

[0120] In the S507, when the power module triggers braking, it parses the power compensation feedforward data table in its local RAM to extract transient compensation power. The digital signal processor (DSP) immediately switches the underlying control logic from the previous constant voltage pre-adjustment mode to the feedforward power compensation mode, releasing the rigid constraint on the DC bus voltage. Specifically, when switching to the feedforward power compensation mode, the DSP pauses the PI regulator in the outer loop of the DC voltage, directly divides the parsed transient compensation power by the current AC grid voltage, generates a reference command for the active component of the grid-side AC current, and forces the corresponding power current output through the underlying current inner loop and space vector pulse width modulation. By releasing the rigid constraint on the DC bus voltage, the system allows the voltage across the energy storage capacitor to fluctuate naturally with the actual energy throughput, avoiding the power module actively drawing away or offsetting the regenerative energy injected by the servo motor to forcibly maintain a constant bus voltage, thus ensuring the maximum reuse of internal regenerative energy at the physical level. The DSP, combined with its local closed-loop PID algorithm, autonomously generates and adjusts the duty cycle of the high-frequency drive signal of the internal power switching transistors. The power module rectifies the AC power from the main grid and injects it into the DC bus according to the transient compensation power limit. The system constructs a real-time power balance model that includes the dynamic characteristics of the charging and discharging of the energy storage capacitor to ensure energy matching.

[0121] Meanwhile, to prevent feedforward model mismatch caused by external physical disturbances such as sudden changes in the mechanical friction coefficient, the power module retains a voltage outer-loop protection logic with a wide hysteresis band while relaxing rigid constraints. When the real-time bus voltage abnormally approaches the preset undervoltage protection safety threshold or the bus overvoltage trigger threshold, the power module automatically takes over and restores the rigid closed-loop voltage regulation to ensure the safe operation and uninterrupted power supply of the underlying system hardware. The formula is as follows:

[0122] ;

[0123] In the formula, The physical capacitance of a storage capacitor; Represents the real-time bus voltage; The time derivative of the real-time bus voltage; Represents transient regenerative power; Represents transient compensation power; Represents rated constant electrical power; Represents real-time command speed; This represents the current operating speed.

[0124] The S508 system connects a voltage Hall sensor between the positive and negative terminals of the DC bus. The Hall sensor acquires the actual voltage signal of the DC bus in real time and sends it to the hardware protection logic circuit. When the actual regenerative energy exceeds the predicted total regenerative energy due to a sudden change in mechanical friction resistance or a deviation in system calculation parameters, the actual voltage signal exceeds the overvoltage trigger threshold locked in the register. The internal comparator of the hardware protection logic circuit then flips and outputs a high-level trigger signal.

[0125] The S509, with its high-level trigger signal, drives the braking chopper circuit connected in parallel with the DC bus. Upon receiving the signal, the insulated-gate bipolar transistor inside the braking chopper circuit is forcibly turned on, forming a low-impedance loop. Excess electrical energy collected on the DC bus is rapidly diverted into an externally mounted high-power bleeder resistor and dissipated as heat. The bleeder action rigidly clamps the actual voltage signal below the bus overvoltage trigger threshold, and the system utilizes this mechanism to completely prevent the risk of physical breakdown of the servo driver inverter bridge and the solid-state lamp array light-emitting devices caused by overvoltage conditions.

[0126] The S510 host computer reads real-time bus voltage data collected by the voltage Hall sensor through a hardware communication interface. During the deceleration and braking phase of the printing carriage, the voltage on the real DC bus side fluctuates dynamically due to the continuous injection of regenerative power and the dynamic replenishment action of the power module. When the curing lamp array is driven by a direct buck chopper topology, if the system maintains fixed switching drive parameters, the fluctuations in the bus voltage will directly cause a shift in the transient input power of the curing lamp array.

[0127] S511, the host computer extracts the pre-locked rated constant power and retrieves the nonlinear driving characteristic model of the curing lamp array obtained through offline calibration. Because the LEDs inside the curing lamp array exhibit exponential semiconductor nonlinear current-voltage characteristics, their equivalent impedance manifests as a dynamic small-signal resistance. Therefore, the conventional linear Ohm's law (i.e.,...) is strictly prohibited. Power extrapolation was performed.

[0128] Therefore, the host computer extracts the real-time command speed of the current communication cycle, multiplies the rated constant power by the ratio of the real-time command speed to the current operating speed, and dynamically attenuates to generate the transient power demand.

[0129] Subsequently, the host computer retrieves the nonlinear electrical characteristic curves of the curing lamp array (including the power-current mapping table and the volt-ampere characteristic curve) obtained through offline calibration. The host computer first uses the power-current mapping table to inversely calculate the transient demand power into the target drive current; then, the host computer substitutes the target drive current into the volt-ampere characteristic curve, looks up the table to obtain the corresponding forward voltage drop at the current operating point, and uses it as the target output voltage.

[0130] Finally, based on the principle of DC buck chopping, the host computer calculates the drive duty cycle that the curing lamp array must execute within the current control cycle by dividing the target output voltage by the real-time bus voltage. The formula is as follows:

[0131] ;

[0132] ;

[0133] ;

[0134] ;

[0135] In the formula, Represents transient electrical power demand; Represents rated constant electrical power; Represents real-time command speed; This represents the current operating speed of the printing vehicle before it enters the deceleration zone; Represents the target drive current; Represents the power-current mapping function; Represents the target output voltage; The mapping function representing the current-voltage characteristic of a light-emitting diode; Represents the drive duty cycle; This represents the real-time bus voltage.

[0136] In the actual hardware driving circuit, the driving duty cycle is used as the feedforward basis setpoint of the converter control loop. The converter is also supplemented by a high-frequency current closed loop for fine-tuning to eliminate the tiny power fluctuations caused by the LED temperature drift effect on the voltage mapping model.

[0137] The S512, the host computer sends the calculated drive duty cycle value to the converter via the communication bus. The converter integrates a microcontroller responsible for the underlying hardware I / O.

[0138] IO stands for Input / Output.

[0139] The microcontroller receives the drive duty cycle value and writes it into its internal high-level timer compare register. Based on hardware timer overflow interrupts and compare-match events, the microcontroller generates a high-frequency control waveform with the corresponding pulse width. The power switches inside the converter directly perform high-frequency turn-on and turn-off actions according to the duty cycle of this high-frequency control waveform.

[0140] The S513 employs inverse proportional modulation logic to establish a negative correlation compensation mapping mechanism between the drive duty cycle and the real-time bus voltage. When the host computer detects an increase in the real-time bus voltage, it proportionally reduces the drive duty cycle to decrease energy injection during a single conduction time; conversely, when the host computer detects a decrease in the real-time bus voltage, it correspondingly increases the drive duty cycle to increase energy injection during a single conduction time. Relying on this closed-loop calculation and dynamic writing mechanism, the system ensures that the actual output power of the curing lamp array strictly follows the transient power demand during any voltage fluctuation cycle, thereby maintaining the physical balance of the light radiation intensity received per unit area within the nonlinear deceleration range of the printing carriage.

[0141] In the S514 converter, the internal microcontroller converts the drive duty cycle into a low-level pulse-width modulation (PWM) waveform. The power switches within the converter then perform high-frequency on / off switching based on this PWM waveform. The curing lamp array subsequently draws transient electrical energy from the DC bus side, matching the drive duty cycle, through the converter. The LEDs within the curing lamp array convert this transient electrical energy into effective light radiation energy and project it onto the corresponding adjacent prediction grid surfaces.

[0142] In S515, to achieve closed-loop control of the photopolymerization operation, the control system performs integral control on the irradiation area of ​​the curing lamp array at the physical level. The host computer retrieves the physical irradiation length of the curing lamp array along the printing carriage's running direction and constructs a virtual illumination sliding window that moves synchronously with the printing carriage based on real-time running coordinates. Within each control cycle, the host computer extracts all predicted grids falling within the range of this virtual illumination sliding window. The host computer synchronously sets the discretized control cycle duration and calculates the exposure area percentage of each predicted grid within the current virtual illumination sliding window through geometric intersection operations.

[0143] The S516, through its integrated accumulator module, utilizes the ideal output characteristics of the buck converter to multiply the real-time bus voltage by the drive duty cycle, calculating the average theoretical drive voltage applied across the curing lamp array. Since the system does not directly collect the high-frequency pulsating current at the lamp array's end, to adhere to the semiconductor's nonlinear characteristics, the host computer substitutes this average theoretical drive voltage into the inverse function of the volt-ampere characteristic curve to obtain an estimated operating current from a table. This average theoretical drive voltage is then multiplied by the estimated operating current, using this nonlinear digital twin to replace calculation and obtain an accurate equivalent power, thus fundamentally avoiding the use of conventional linear power formulas (…). This calculation addresses the inherent deviation in optical radiation energy caused by nonlinear light-emitting devices. The host computer calculates the transient optical power based on the photoelectric conversion efficiency and then discretizes and accumulates this transient optical power over time to obtain the additional optical radiation energy in each control cycle. The host computer then evenly distributes this additional optical radiation energy to the equivalent cumulative total optical radiation energy of the corresponding grid according to the area ratio of the predicted grid within the sliding window. The formula is as follows:

[0144] ;

[0145] In the formula, Represents the equivalent cumulative total energy of light radiation from the grid; Representing the Real-time bus voltage for each control cycle; Representing the The drive duty cycle of each control cycle; The inverse mapping function representing the current-voltage characteristic of a light-emitting diode (i.e., looking up the current from the voltage); The duration of the control cycle representing the discretization; Represents photoelectric conversion efficiency; This represents the percentage of the exposed area of ​​the corresponding grid within the virtual lighting sliding window.

[0146] In the S517, the software comparison logic unit inside the host computer traverses the deceleration grid queue. When it determines that the equivalent cumulative total light radiation energy of a specific predicted grid is greater than or equal to its target total energy, it marks it as solidified. However, due to the large physical size of the lamp array, the host computer does not immediately shut down the lamp array. Instead, it continuously compares whether there are any predicted grids within the sliding window that have not yet reached the target total energy. Only when the sliding window completely crosses the physical boundary of the deceleration grid queue with the printing carriage, and all grids in the queue are marked as solidified, does the converter drive the internal power switch to enter a continuous off state, and the solidified lamp array stops emitting light. Subsequently, the host computer sends a control recovery command to the power module, and the digital signal processor exits the feedforward power compensation mode, resuming rigid closed-loop regulation of the rated bus voltage.

[0147] Specific application examples are as follows:

[0148] To verify the engineering feasibility of the above specific implementation method and to quantify the cost reduction and efficiency improvement results of the multi-mode variable frequency energy-saving drive control system on the actual hardware base, a detailed specific application example is provided below based on the physical parameters of a mainstream industrial-grade UV flatbed printer.

[0149] The hardware base in this embodiment is configured as follows: the total load mass of the printing carriage is 50kg; the servo motor is driven by a synchronous belt with a mechanical transmission efficiency of 0.9; the power generation efficiency of the servo motor is 0.9 (i.e., the overall energy conversion efficiency is 0.81); and the guide rail friction coefficient is 0.02. The physical capacitance of the energy storage capacitor connected in parallel across the DC bus is 0.0047F (4700μF); the rated bus voltage under normal power supply conditions is 310V. The overvoltage trigger threshold of the bus set by the hardware protection logic circuit is 340V. The photoelectric conversion efficiency of the curing lamp array is 0.4.

[0150] In a specific printing task, after performing spatial analysis, the host computer determined that the printing vehicle was about to enter the deceleration zone at its current speed of 1.5 m / s. The deceleration buffer distance constant was set to 0.15 m. Through look-ahead data extraction, the host computer found that the baseline solidification energy threshold within the deceleration grid queue was 0.3 J, and the physical length of a single predicted grid in the two-dimensional spatial coordinate system was 0.01 m.

[0151] The host computer first calculates the rated constant power for photocuring operations that meets the baseline curing energy threshold using the formula:

[0152] Substitute the physical data: The host computer stores 112.5W as the rated constant power in the feedforward calculation register and locks it.

[0153] Subsequently, the host computer performs deceleration trajectory planning and derives the equivalent average deceleration acceleration and peak deceleration acceleration:

[0154] Substituting the data, we get: Therefore, the total deceleration time is calculated as follows: Peak deceleration This value does not exceed the safe deceleration limit of the servo motor, therefore the host computer uses a nonlinear deceleration model to generate a cycloidal speed command:

[0155] ;

[0156] In the power extrapolation and feedforward voltage reduction stage, the host computer uses transient deceleration acceleration and real-time command speed to construct a transient regenerative power model:

[0157] ;

[0158] Among them, the total mechanical resistance of the system The host computer performs a time definite integral calculation on the model over a total deceleration time of 0.2 seconds:

[0159] ;

[0160] The calculated total regenerative energy to be injected into the DC bus during the nonlinear deceleration phase of the servo motor is approximately 28.5 J. Meanwhile, the expected total dynamic energy consumed by the curing lamp array is... Since the predicted total regeneration energy is greater than the expected dynamic total energy consumption, the net charging energy is 17.25 J. Based on this, the host computer calculates the target bus voltage (i.e., the feedforward step-down trigger threshold) in reverse:

[0161] ;

[0162] Substitute the data: The host computer forcibly rounds the target bus voltage to 298V and sends it as a voltage bias control frame. After receiving the frame, the power module actively reduces the output duty cycle, so that the DC bus voltage smoothly drops to 298V before the physical braking action occurs, reserving sufficient electric field energy space.

[0163] When the printing vehicle enters the deceleration zone and performs a deceleration action, the transient compensation power calculation formula is simultaneously activated:

[0164] ;

[0165] When regenerative energy is in surplus (i.e., transient demand power is less than transient regenerative power), the host computer sets the transient compensation power to zero; when regenerative energy is insufficient, the power module accurately injects main grid power according to the power compensation feedforward data table. Throughout the energy interleaving process, the converter generates the drive duty cycle based on the target output voltage and the real-time bus voltage.

[0166] ;

[0167] The converter uses the drive duty cycle for inverse proportional modulation to ensure that the transient optical power of the curing lamp array strictly matches the target total energy of adjacent prediction grids. The host computer ultimately determines the equivalent cumulative total optical radiation energy using an integral formula, and shuts off the lamp array after the curing conditions are met.

[0168] ;

[0169] In the experimental verification and effect comparison phase, we built a dual-sided control test platform. The traditional drive control system did not employ feedforward buck and inverse proportional modulation logic. Under the same operating conditions, during braking, the regenerative energy pumped by the servo motor had nowhere to be released instantly, causing the real-time bus voltage to surge to 340V within 0.08 seconds. The hardware protection logic circuit was forced to trigger the braking chopper circuit at high frequency, and a large amount of regenerative energy was converted into heat by the bleeder resistor and wasted.

[0170] Meanwhile, due to the lack of decoupling mapping based on nonlinear current-voltage characteristics, the output optical power of the curing lamp array in the traditional system exhibits significant distortion when the voltage fluctuates drastically, resulting in over-curing or uneven curing of ink droplets in the deceleration range.

[0171] In contrast, the control system of this invention, thanks to its accurate feedforward buck trigger threshold setting and transient power compensation mechanism, ensures that the regenerative electrical energy generated by the printing carriage during deceleration is completely absorbed into the energy storage capacitor of the DC bus and seamlessly diverted by the converter to the curing lamp array for consumption. Throughout the braking cycle, the real-time bus voltage smoothly rises from 298V but only reaches a maximum of around 315V, never touching the 340V bus overvoltage trigger threshold, thus preventing heat loss from the bleeder resistor. The system achieves 100% lossless cross-boundary transfer of mechanical kinetic energy to light radiation energy and maintains extremely stable transient power demand tracking through digital twin calculations.

[0172] The conclusions are as follows:

[0173] See Figure 8 , Figure 8 The comparison of solid and dashed lines in the diagram visually demonstrates that during the nonlinear deceleration of the printing vehicle, this invention successfully clamps the real-time bus voltage within a safe and efficient fluctuation range by utilizing the energy buffer space constructed by the feedforward voltage reduction trigger threshold. This effectively avoids hardware-level energy leakage caused by voltage exceeding limits in traditional solutions. While ensuring the safe operation of the underlying servo driver and the curing lamp array, it also achieves the maximum closed-loop reuse of the system's regenerated electrical energy.

Claims

1. A multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer, characterized in that, It includes a host computer, DC bus, power module, servo driver, converter, servo motor, printing carriage, curing lamp array and communication bus; The DC bus connects the power module, the servo driver, and the converter; the servo driver connects to the servo motor, and the servo motor drives the printing carriage. The converter is connected to the curing lamp array; the host computer is connected to the communication bus, and the power module, the servo driver and the converter are all connected in parallel to the communication bus; The host computer reads image data, generates control commands, deceleration and acceleration, and compensation power. The host computer sends the control commands and deceleration and acceleration to the servo driver through the communication bus. The host computer sets the feedforward buck trigger threshold, and the host computer sends the feedforward buck trigger threshold and the compensation power to the power module through the communication bus; The servo motor enters the power generation state when the printing carriage performs a deceleration action. The servo motor converts the rotor kinetic energy into regenerative electrical energy and injects it into the DC bus in reverse along the servo driver. The converter directs the regenerative electrical energy to the curing lamp array.

2. The multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer according to claim 1, characterized in that, The DC bus is connected in parallel with a hardware protection module that includes a voltage Hall sensor, hardware protection logic circuit, braking chopper circuit and bleeder resistor. The voltage Hall sensor is connected to the hardware protection logic circuit, the hardware protection logic circuit is connected to the control terminal of the braking chopper circuit, and the output terminal of the braking chopper circuit is connected in series with the discharge resistor. The hardware protection logic circuit determines the conduction state of the braking chopper circuit based on the signal fed back by the voltage Hall sensor, thereby releasing the regenerated electrical energy.

3. The multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer according to claim 1, characterized in that, The power module uses a PWM active rectifier with controllable duty cycle output characteristics, and the converter is a DC-DC buck chopper converter. The power module receives the feedforward buck trigger threshold reduction and performs bus voltage pre-adjustment on the output duty cycle of the DC bus; The power module receives the compensation power and dynamically replenishes the DC bus.

4. The multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer according to claim 1, characterized in that, The servo driver integrates a microcontroller, a speed gain register, and a torque limit register. The control commands include high-density commands and economic commands; The host computer sends the high-density command to the servo driver, the microcontroller writes the target gain value to the speed gain register, and the microcontroller writes the peak current limit value to the torque limit register to establish a high-bandwidth response state. The host computer sends the economic command to the servo driver, the microcontroller writes the attenuation gain value to the speed gain register, and the microcontroller writes the clamping current limit value to the torque limit register to establish a low-frequency following state.

5. The multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer according to claim 1, characterized in that, The host computer reads the coordinates of the printing vehicle and determines that the printing vehicle has entered the deceleration zone; The host computer calculates the equivalent average deceleration acceleration by combining the current running speed and the deceleration buffer distance constant, and the host computer deduces the peak deceleration acceleration by combining the smooth transition coefficient. The host computer writes the equivalent average deceleration acceleration and the peak deceleration acceleration into the internal motion planning control block. The host computer extracts the equivalent average deceleration and the peak deceleration latched by the motion planning control block to generate a nonlinear deceleration trajectory, and the host computer sends the deceleration acceleration to the servo driver according to the deceleration trajectory.

6. The multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer according to claim 1, characterized in that, The host computer divides the two-dimensional spatial coordinate system into a matrix-arranged prediction grid according to a fixed size step. The host computer extracts the set of pixels inside the prediction grid and extracts the ink droplet density and pixel area of ​​a single pixel; The host computer calculates the total target energy corresponding to the predicted grid by combining the photosensitive response constant; The host computer compares the target total energy with the first threshold input comparator logic unit and generates the control command.

7. A multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer according to claim 6, characterized in that, The host computer extracts transient deceleration and acceleration to construct transient regenerative power; The host computer sets a rated constant power based on the target total energy; The host computer combines the real-time command speed and the rated constant power to obtain the transient power demand. The host computer uses its integrated microprocessor to compare the transient demand power and the transient regenerative power. The microprocessor calculates the difference to obtain the compensation power and sends the compensation power to the power module.

8. The multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer according to claim 7, characterized in that, The host computer calls the internally integrated numerical integration calculation module to perform integral calculation on the transient regenerative power to obtain the predicted total regenerative energy; The host computer combines the predicted total regeneration energy and the expected dynamic total energy consumption to obtain the net charging energy; The host computer obtains the target bus voltage based on the net charging energy and physical capacitance, and sets the target bus voltage as the feedforward buck trigger threshold of the DC bus.

9. A multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer according to claim 8, characterized in that, The host computer extracts the real-time command speed and the rated constant power dynamic decay to generate the transient demand power. The host computer calculates the transient power demand into a target drive current, and the host computer obtains the target output voltage based on the target drive current. The host computer combines the target output voltage and the real-time bus voltage to obtain the drive duty cycle; The host computer sends the driving duty cycle to the converter, and the converter adjusts the conduction pulse width of the curing lamp array according to the driving duty cycle.

10. A multi-mode frequency conversion energy-saving drive control system for a UV flatbed printer according to claim 9, characterized in that, The host computer calls the internally integrated accumulator module to obtain the average theoretical drive voltage by combining the real-time bus voltage with the drive duty cycle; The host computer obtains the estimated operating current based on the average theoretical drive voltage; The host computer combines the average theoretical driving voltage and the estimated operating current to obtain the equivalent electrical power. The host computer combines the equivalent electrical power and the photoelectric conversion efficiency to calculate the transient optical power. The host computer accumulates the transient optical power to obtain the equivalent cumulative total optical radiation energy.

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