Aluminum material extrusion forming closed-loop control system and method

Abstract

The application relates to the technical field of industrial control systems and discloses an aluminum material extrusion forming closed-loop regulation and control system and method, which comprises the following units: a working condition data synchronous unit for collecting direct-current bus current and current stroke displacement; a discrete state observation unit for constructing resistance drift characteristics through differential operation and analyzing state jump scalar; a dynamic feedback matrix control unit for regulating and reducing control gain component weight according to the state jump scalar and outputting a target regulation and control instruction stream; and an anti-saturation dynamic feedback clamping unit for clearing integral accumulation items and switching to sliding mode variable structure control when the direct-current bus current reaches 95% of the rated value. The application utilizes the monotonicity of current and displacement gradients to solve resistance variation, provides a feedforward hedging capability to eliminate instruction phase misplacement, suppresses loop oscillation and avoids saturation deadlock.

Description

Technical Field

[0001] This invention relates to a closed-loop control system and method for aluminum extrusion molding, belonging to the field of industrial control system technology. Background Technology

[0002] Current industrial control closed-loop circuits typically use physical sensors to acquire the physical state parameters of the controlled object. By using temperature, stress, and rheological rate as feedback signal sources, a continuous correction circuit is constructed to maintain steady-state equilibrium in the process. When the controlled metal material undergoes plastic rheology under load, its internal lattice slip and energy dissipation cause the physical deformation resistance of the material to deflect. This physical deformation resistance is reversed and applied to the power bus of the frequency converter through the transmission mechanism, causing a coordinated shift in the electrical characteristics of the drive motor bus and the stroke displacement sequence.

[0003] When the above architecture is applied to the aluminum extrusion molding process, due to the intense thermal multi-field nonlinear coupling accompanying material rheology, the hysteresis signals collected by external measurement components cannot characterize the transient rheological state inside the die in real time. This leads to accumulated hysteresis delays in conventional loops. Existing adjustment methods mostly rely on external hardware structural dimensions such as the mechanical components at the front end of the extruder or the shape of the rollers for correction. Hardware-level fine-tuning is very prone to touching the physical processing boundaries and cannot fundamentally solve the problem of insufficient dynamic instability at the system software control level. For example, Chinese invention patent with authorization announcement number CN118543693B discloses... An aluminum extrusion forming equipment uses a rigid mechanical gear and rack transmission to convert the propulsion displacement into a rotary cutting drive, controlling the cost of the external power source. However, the solution is based on the ideal physical premise that the material rheology is uniform and undisturbed. In actual processing, the transient rheological resistance of aluminum material caused by strong coupling of multiple thermal fields has time-varying nonlinear characteristics. Pure hardware linkage adjustment completely deprives the flexible adaptive adjustment mechanism of the software control loop. When faced with a sudden change in material hardness, the rigid transmission structure cannot achieve real-time clamping of control gain and feedforward offset, which can easily cause fatigue wear of mechanical structure or system closed-loop divergence deadlock.

[0004] Therefore, the technical problem to be solved by this invention is how to construct a discrete joint differential observation structure by utilizing the electrical characteristics of the drive bus and the displacement sequence, and implement gain adaptive anti-saturation clamping in the state transition to suppress the oscillation overshoot of the feedback loop. Summary of the Invention

[0005] To address the problems in the background art, the technical solution of the present invention is as follows: a closed-loop control system for aluminum extrusion molding, the system comprising: The operating data synchronization unit is used to collect the DC bus current and current travel displacement of the power drive frequency converter; The discrete state observation unit, connected to the working condition data synchronization unit, is used to perform discrete difference matrix operations on the received DC bus current and the current travel displacement to construct the resistance drift characteristics that characterize the deformation resistance of the controlled aluminum material, and to analyze the state jump scalar based on the resistance drift characteristics. The dynamic feedback matrix control unit is connected to the discrete state observation unit. It is used to reduce the weights of each component of the control gain matrix according to the state jump scalar, and to saturate and clamp the control gain matrix and output the target control command stream when the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold. The anti-saturation dynamic feedback clamping unit, connected to the dynamic feedback matrix control unit, is used to clear the integral accumulation term when the DC bus current reaches 95% of the rated operating current value, and switch the control path to sliding mode variable structure control. It constrains the output amplitude range of the target regulation command flow by outputting the sliding mode control quantity.

[0006] Preferably, the system further includes a feedforward hysteresis damping compensation unit; the feedforward hysteresis damping compensation unit is connected to the dynamic feedback matrix control unit and is used to extract historical reverse control residuals and correct the output slope of the target control command flow online; the dynamic feedback matrix control unit has a built-in multi-layer state machine containing multiple discrete state layers, each discrete state layer is monotonically bound to a unique memory address index value, which is used to shut down continuous feedback control and activate the cascaded control branch of the multi-layer state machine when the resistance drift characteristics change abruptly.

[0007] Preferably, the operating condition data synchronization unit includes a sampling pulse generator and a synchronization buffer memory; the operating condition data synchronization unit generates a 10ms sampling period through the sampling pulse generator, and uses the synchronization buffer memory to capture the DC bus current and the current travel displacement in parallel, and outputs operating condition data with time alignment.

[0008] Preferably, when the dynamic feedback matrix control unit activates the cascaded control branch of the multi-level state machine, it calculates the monotonic sag component based on the polarity and magnitude of the state transition scalar, and reduces the weight of each dimension of the control gain matrix according to the monotonic sag component, thereby completing gain oversaturation clamping before the target control command stream is output to the power drive inverter.

[0009] Preferably, the anti-saturation dynamic feedback clamping unit includes an integral cut-off module and a sliding mode calculation module. When the DC bus current reaches 95% of the rated operating current value, the anti-saturation dynamic feedback clamping unit clears the integral accumulation term through the integral cut-off module and switches the calculation path of the target control command flow to the sliding mode calculation module to calculate the sliding mode control quantity using the exponential reaching law, thereby limiting the control gain divergence boundary.

[0010] Preferably, the feedforward hysteresis damping compensation unit limits the fine-tuning range of the output slope of the target control command stream, constraining the fine-tuning range of the output slope to within 0.8 to 1.2 times the reference output slope, so as to reduce the phase lag of the target control command stream.

[0011] Preferably, the discrete state observation unit is used to perform a second-order difference matrix transformation on the DC bus current in order to filter out high-frequency operating condition interference signals in the discrete logic space, extract the slip component that reflects the trend of rheological state change of aluminum material in the extrusion die, and determine the slip component as resistance drift characteristic.

[0012] Preferably, the system further includes a bus arbitration unit; the bus arbitration unit is connected to the operating condition data synchronization unit, the discrete state observation unit, the dynamic feedback matrix control unit, and the anti-saturation dynamic feedback clamping unit respectively, and is used to construct a fixed priority communication architecture in the closed-loop control loop, and set the sliding mode control quantity output by the anti-saturation dynamic feedback clamping unit to have the highest communication priority, directly covering the target control command stream output by the dynamic feedback matrix control unit.

[0013] Preferably, the entire system is housed inside a distributed industrial control chassis, and the system is interconnected with an external power drive inverter via a shielded industrial Ethernet bus, sending the calculated target control command stream to the power drive inverter in real time.

[0014] A closed-loop control method for aluminum extrusion molding, used to operate an aluminum extrusion molding closed-loop control system, includes the following steps: Step S1: Use the operating condition data synchronization unit to collect the DC bus current and current travel displacement of the power drive frequency converter; Step S2: Use the discrete state observation unit to perform discrete difference matrix operation on the DC bus current and the current travel displacement to construct the resistance drift characteristics that characterize the deformation resistance of the controlled aluminum material, and analyze the state jump scalar based on the resistance drift characteristics. Step S3: The dynamic feedback matrix control unit adjusts the weights of each component of the control gain matrix according to the state jump scalar, and when the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold, the control gain matrix is ​​saturated and clamped and the target control command stream is output. Step S4: When the DC bus current reaches 95% of the rated operating current value, the integral accumulation term is cleared using the anti-saturation dynamic feedback clamping unit, and the control path is switched to sliding mode variable structure control. The output amplitude range of the target regulation command stream is constrained by the output sliding mode control quantity.

[0015] Compared with the prior art, the beneficial effects of the present invention are: 1. In the closed-loop control of aluminum extrusion molding, the working condition data synchronization node high-frequency collects the characteristic quantity of DC bus current and the current stroke displacement sequence of the axial degree of freedom mechanism. The discrete state observation unit constructs a discrete joint differential operator to combine the current change and displacement change to generate a state jump scalar online. This mechanism avoids the traditional physical perception path that relies on heat conduction or mechanical stress transmission. It utilizes the physical monotonicity of electrical characteristics and displacement gradient to directly solve the transient rheological resistance deflection of the controlled entity inside the controller. Since the electrical jump has zero thermal resistance characteristics, the feedback loop obtains forward active feedforward counterbalancing capability, eliminates the phase misalignment between the control command and the physical entity state, and avoids loop divergence oscillation.

[0016] 2. The dynamic feedback matrix control core is pre-configured with a hierarchical state machine containing multiple discrete spatiotemporal topology layers. Each layer is monotonically bound to a unique memory address index value. When the absolute value of the first-order time-domain difference of the DC bus current characteristic quantity exceeds the preset discrete noise hard exclusion boundary, the material rheological resistance undergoes a step change. The control core closes the continuous feedback control path and directly activates the conditional cascaded control branch of the state machine. This branch monotonically reduces the weights of each dimension of the control gain matrix according to the polarity and magnitude of the state jump scalar, completing the gain oversaturation clamping before the instruction is issued, thereby solving the closed-loop control divergence deadlock caused by the oversaturation of control weights.

[0017] 3. The anti-saturation dynamic feedback clamping unit is connected to the dynamic feedback matrix control core and is used to monitor the current characteristics of the power drive frequency converter. When the DC bus current reaches the rigid safety boundary threshold of the rated operating current value, the control unit strips the original integral accumulation term and forces the control law calculation path to switch to the truncated sliding mode variable structure control flow, constraining the output amplitude range of the target control command flow. This switching mechanism generates segmented gain attenuation at the physical boundary point, forcibly locking the control gain divergence boundary, realizing adaptive adjustment of control parameters under extreme conditions, and solving the closed-loop divergence problem caused by integral saturation of the control system. Attached Figure Description

[0018] Figure 1 This is a flowchart of the multi-unit collaborative cascade closed-loop control steps of the present invention; Figure 2 This diagram illustrates the evolution mechanism of continuous feedback to sliding mode variable structure control in this invention.

[0019] The objectives, features, and advantages of this invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0020] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0021] A closed-loop control system for aluminum extrusion molding, the system comprising: The operating data synchronization unit is used to collect the DC bus current and current travel displacement of the power drive frequency converter; The discrete state observation unit, connected to the working condition data synchronization unit, is used to perform discrete difference matrix operations on the received DC bus current and the current travel displacement to construct the resistance drift characteristics that characterize the deformation resistance of the controlled aluminum material, and to analyze the state jump scalar based on the resistance drift characteristics. The dynamic feedback matrix control unit is connected to the discrete state observation unit. It is used to reduce the weights of each component of the control gain matrix according to the state jump scalar, and to saturate and clamp the control gain matrix and output the target control command stream when the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold. The anti-saturation dynamic feedback clamping unit, connected to the dynamic feedback matrix control unit, is used to clear the integral accumulation term when the DC bus current reaches 95% of the rated operating current value, and switch the control path to sliding mode variable structure control. It constrains the output amplitude range of the target regulation command flow by outputting the sliding mode control quantity.

[0022] Preferably, the system further includes a feedforward hysteresis damping compensation unit; the feedforward hysteresis damping compensation unit is connected to the dynamic feedback matrix control unit and is used to extract historical reverse control residuals and correct the output slope of the target control command flow online; the dynamic feedback matrix control unit has a built-in multi-layer state machine containing multiple discrete state layers, each discrete state layer is monotonically bound to a unique memory address index value, which is used to shut down continuous feedback control and activate the cascaded control branch of the multi-layer state machine when the resistance drift characteristics change abruptly.

[0023] Preferably, the operating condition data synchronization unit includes a sampling pulse generator and a synchronization buffer memory; the operating condition data synchronization unit generates a 10ms sampling period through the sampling pulse generator, and uses the synchronization buffer memory to capture the DC bus current and the current travel displacement in parallel, and outputs operating condition data with time alignment.

[0024] Preferably, when the dynamic feedback matrix control unit activates the cascaded control branch of the multi-level state machine, it calculates the monotonic sag component based on the polarity and magnitude of the state transition scalar, and reduces the weight of each dimension of the control gain matrix according to the monotonic sag component, thereby completing gain oversaturation clamping before the target control command stream is output to the power drive inverter.

[0025] Preferably, the anti-saturation dynamic feedback clamping unit includes an integral cut-off module and a sliding mode calculation module. When the DC bus current reaches 95% of the rated operating current value, the anti-saturation dynamic feedback clamping unit clears the integral accumulation term through the integral cut-off module and switches the calculation path of the target control command flow to the sliding mode calculation module to calculate the sliding mode control quantity using the exponential reaching law, thereby limiting the control gain divergence boundary.

[0026] Preferably, the feedforward hysteresis damping compensation unit limits the fine-tuning range of the output slope of the target control command stream, constraining the fine-tuning range of the output slope to within 0.8 to 1.2 times the reference output slope, so as to reduce the phase lag of the target control command stream.

[0027] Preferably, the discrete state observation unit is used to perform a second-order difference matrix transformation on the DC bus current in order to filter out high-frequency operating condition interference signals in the discrete logic space, extract the slip component that reflects the trend of rheological state change of aluminum material in the extrusion die, and determine the slip component as resistance drift characteristic.

[0028] Preferably, the system further includes a bus arbitration unit; the bus arbitration unit is connected to the operating condition data synchronization unit, the discrete state observation unit, the dynamic feedback matrix control unit, and the anti-saturation dynamic feedback clamping unit respectively, and is used to construct a fixed priority communication architecture in the closed-loop control loop, and set the sliding mode control quantity output by the anti-saturation dynamic feedback clamping unit to have the highest communication priority, directly covering the target control command stream output by the dynamic feedback matrix control unit.

[0029] Preferably, the entire system is housed inside a distributed industrial control chassis, and the system is interconnected with an external power drive inverter via a shielded industrial Ethernet bus, sending the calculated target control command stream to the power drive inverter in real time.

[0030] A closed-loop control method for aluminum extrusion molding, used to operate an aluminum extrusion molding closed-loop control system, includes the following steps: Step S1: Use the operating condition data synchronization unit to collect the DC bus current and current travel displacement of the power drive frequency converter; Step S2: Use the discrete state observation unit to perform discrete difference matrix operation on the DC bus current and the current travel displacement to construct the resistance drift characteristics that characterize the deformation resistance of the controlled aluminum material, and analyze the state jump scalar based on the resistance drift characteristics. Step S3: The dynamic feedback matrix control unit adjusts the weights of each component of the control gain matrix according to the state jump scalar, and when the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold, the control gain matrix is ​​saturated and clamped and the target control command stream is output. Step S4: When the DC bus current reaches 95% of the rated operating current value, the integral accumulation term is cleared using the anti-saturation dynamic feedback clamping unit, and the control path is switched to sliding mode variable structure control. The output amplitude range of the target regulation command stream is constrained by the output sliding mode control quantity.

[0031] Example 1: The closed-loop control system for aluminum extrusion molding in this example is set in the control link of the aluminum extrusion molding equipment. It is used to perform multivariable nonlinear adaptive adjustment under time-varying disturbance conditions. The system includes a working condition data synchronization unit, a discrete state observation unit, a dynamic feedback matrix control unit, an anti-saturation dynamic feedback clamping unit, and a feedforward hysteresis damping compensation unit. The working condition data synchronization unit is used to collect the DC bus current and current travel displacement of the power drive frequency converter. The output of the working condition data synchronization unit is connected to the discrete state observation unit. The output of the discrete state observation unit is connected to the dynamic feedback matrix control unit. The output of the dynamic feedback matrix control unit is connected to the anti-saturation dynamic feedback clamping unit. The power drive inverter is connected, and the feedforward hysteresis damping compensation unit is connected to the dynamic feedback matrix control unit. The operating condition data synchronization unit includes a sampling pulse generator and a synchronous buffer memory. The sampling pulse generator generates a 10ms sampling period and outputs a sampling trigger signal to the synchronous buffer memory in each sampling period. The synchronous buffer memory captures the DC bus current and the current travel displacement in parallel under the same sampling trigger signal, and outputs the time-aligned operating condition data to the discrete state observation unit. The discrete state observation unit performs discrete difference matrix operations on the DC bus current and the current travel displacement to construct the resistance drift characteristics that characterize the deformation resistance of the controlled aluminum material, and analyzes the state jump scalar based on the resistance drift characteristics.

[0032] The data flow processing method of discrete difference matrix operations within the controller is as follows: After receiving time-aligned operating condition data in the current control cycle, the discrete state observation unit extracts the DC bus current value and the current travel displacement value at the current sampling moment, and retrieves the historical DC bus current value and travel displacement value from the previous sampling moment. Then, it subtracts the historical current value from the current value to obtain the first-order differential change of the current, and subtracts the historical displacement value from the current displacement value to obtain the first-order differential change of the displacement. Next, it uses preset normalization mapping coefficients to perform dimensionless processing on the first-order differential change of the current and the first-order differential change of the displacement, respectively. The processed current change feature term is used as the first dimension element of a 2D column vector, and the processed displacement change feature term is used as the second dimension element of this 2D column vector, constructing an operating condition state vector. Based on this, the operating condition state vector is compared with the 2D column vector pre-stored within the controller. A matrix multiplication operation is performed on the second-order time-varying state transition matrix to obtain a resistance observation matrix that contains changes in the internal flow characteristics of the material. This resistance observation matrix serves as the mathematical carrier of resistance drift characteristics. Finally, the discrete state observation unit performs trace operation on the resistance observation matrix, that is, calculates the algebraic sum of the elements on the main diagonal of the matrix, thereby compressing and reducing the dimensionality of the multidimensional matrix data, and outputting a scalar value that characterizes the intensity of the sudden change in stress on the controlled aluminum material. This value serves as the state jump scalar for the current period and is used for subsequent adaptive adjustment actions. The second-order time-varying state transition matrix pre-stored in the discrete state observation unit has its initial coefficients obtained offline by recursive least squares algorithm based on the relative change rate sequence of DC bus current and the relative change rate sequence of stroke displacement collected under the test extrusion condition. The two diagonal elements of the initial state transition matrix are set to a constant 1, and the remaining elements are set to the system sampling period value of 0.01 seconds.

[0033] During online adjustment, when the state transition scalar is within the preset fluctuation threshold, the controller introduces a forgetting factor of 0.98 to update the element values ​​of the state transition matrix. When the resistance drift characteristic changes and the state transition scalar exceeds the preset fluctuation threshold, the controller shuts off the forgetting factor update path and directly increases the algebraic multiplication coefficient of the off-diagonal elements with respect to the first-order difference term of the current, thereby improving the sensitivity of the resistance observation matrix to capturing transient deformation resistance changes. The dynamic feedback matrix control unit receives the state transition scalar, adjusts the weights of each component of the control gain matrix according to the state transition scalar, and performs saturation clamping on the control gain matrix and outputs the target control command stream when the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold. The dynamic feedback matrix control unit has a built-in multi-layer state machine containing multiple discrete state layers. Each discrete state layer is monotonically bound to a unique memory address index value. When the resistance drift characteristic changes, the continuous feedback control is turned off and the cascaded control branch of the multi-layer state machine is activated. The feedforward hysteresis damping compensation unit extracts the historical reverse control residual and corrects the output slope of the target control command stream online.

[0034] The anti-saturation dynamic feedback clamping unit receives the target control command stream and continuously monitors the DC bus current. When the DC bus current reaches 95% of the rated operating current, it clears the integral accumulation term and switches the control path to sliding mode variable structure control. It then constrains the output amplitude range of the target control command stream by outputting the sliding mode control quantity before sending it to the power drive inverter. This ensures that the integral accumulation when the DC bus current reaches 95% of the rated operating current is synchronously constrained with the output amplitude of the target control command stream. The determination of the 95% physical switching boundary is primarily based on the combined derivation of the overload thermal protection curve and drain current overshoot margin of the power inverter's insulated gate bipolar transistor module. If the switching threshold is set too low, for example, below 90% of the rated current, when the extruder is operating at full load limit, it will cause problems during normal extrusion. Frequent false triggering of control path switching causes the system to prematurely lose its continuous adaptive fine-tuning capability, resulting in extrusion ripples on the aluminum surface. Conversely, if the threshold is set too high, such as above 98% of the rated current, there is a hardware electrical delay and filtering hysteresis of approximately 15 milliseconds between the control chip detecting overcurrent, executing integral cutoff, and the actual output of the sliding mode control quantity and pulling down the bus current. Within this delay window, the bus current will continue to rise inertia and directly exceed the 100% rated safety red line, which can easily trigger the main drive inverter to trip the hardware overcurrent protection or burn out the power devices. Therefore, after multiple destructive overload tests under extreme conditions, 95% was selected as the rigid critical point. This leaves a 5% current buffer rise dead zone to offset the hardware dead zone delay and ensures that the anti-saturation clamping action can accurately lock the gain divergence boundary before the hardware devices are damaged.

[0035] Example 2: When the DC bus current does not reach 95% of the rated operating current, the target control command stream output by the dynamic feedback matrix control unit is sent to the power drive inverter according to the continuous feedback control path. The feedforward hysteresis damping compensation unit maintains its connection with the dynamic feedback matrix control unit and receives the target control command stream. Multiple discrete state layers maintain the corresponding cascaded control branches in an active state according to their monotonically bound unique memory address index values. When the resistance drift characteristic changes abruptly, the dynamic feedback matrix control unit closes the continuous feedback control and activates the cascaded control branches of the multi-layer state machine. The dynamic feedback matrix control unit calculates the monotonically decreasing component based on the polarity and amplitude of the state change scalar, and reduces the weight of each dimension of the control gain matrix based on the monotonically decreasing component. Gain oversaturation clamping is completed before the target control command stream is output to the power drive inverter. During execution, the controller's central processing core reads the absolute value and polarity of the current state jump scalar. If a negative scalar polarity is detected, the original gain weight remains unchanged, thus achieving unidirectional adaptive gain clamping protection. If a positive scalar polarity is detected and its absolute value exceeds a preset fluctuation threshold, it indicates a step increase in the deformation resistance of the aluminum material. At this time, the system uses an exponential decay function to calculate a proportional factor between 0 and 1, which monotonically decreases as the scalar amplitude increases. Then, the controller multiplies the initial gain coefficients of the three main diagonal dimensions responsible for proportional, integral, and derivative adjustments in the control gain matrix by the same proportional factor, thereby achieving a monotonically proportional reduction in the weights of each dimension component. This causes the controller's output control strength to converge instantaneously, avoiding control overshoot caused by sudden changes in external hardness and ensuring a smooth transition when the deformation resistance changes abruptly.

[0036] The feedforward hysteresis damping compensation unit extracts historical reverse control residuals from the target control command stream retained within the continuous control cycle, and corrects the output slope of the target control command stream online based on the historical reverse control residuals. The fine-tuning range of the output slope is constrained to 0.8 to 1.2 times the reference output slope, ensuring that the target control command stream remains within the output slope fine-tuning range before being output to the anti-saturation dynamic feedback clamping unit. The engineering design basis for constraining the output slope fine-tuning range to 0.8 to 1.2 times the reference output slope is as follows: The reference output slope corresponds to the power drive inverter at standard discharge... Under the process, the dynamic voltage-frequency ratio response speed, when overcoming transmission hysteresis, if the correction slope is less than 0.8 times, the rise or fall speed of the command signal will be slower than the change of the back electromotive force of the drive motor, causing the control system to physically produce phase lag, resulting in crawling or jamming of the extrusion shaft; while if the correction slope is greater than 1.2 times, the step change rate of the command intensity will exceed the communication cycle of the shielded industrial Ethernet bus and the dynamic response limit of the power regulator inside the frequency converter, making the inverter unable to track the high-frequency components of the command, thereby exciting transient high-order harmonics on the power bus and inducing secondary oscillations in the feedback loop.

[0037] Therefore, by using a pre-set dynamic bandwidth test to limit the fine-tuning range to within 0.8 to 1.2 times the linear saturation edge, it is possible to ensure command agility to eliminate phase lag while completely avoiding hardware runaway caused by control gain. The stroke displacement constant table used in the adaptive degradation optimization module embedded in the feedforward hysteresis damping compensation unit is pre-established during system initialization through offline process rheological testing. The complete stroke of the extrusion shaft is divided into 20 sub-intervals according to the axial length. The power drive inverter in each sub-interval is measured and recorded under isothermal and constant speed extrusion conditions. The expected average DC bus current during discharge is used to form a one-dimensional array containing 20 data items and directly written into non-volatile memory. When the transient current jump slope exceeds the rated safe change rate for three consecutive sampling cycles and the weight update chain is forcibly suspended, the controller interrupts all real-time matrix operations and directly reads the expected average DC bus current of the corresponding sub-interval as the address index using the currently collected travel displacement data as the open-loop reference setpoint output of the target control command stream. In extreme interference environments, the algorithm directly enters the segmented setpoint control mode, and the DC bus current reaches the rated operating current. When the flow value reaches 95%, the integral cutoff module in the anti-saturation dynamic feedback clamping unit clears the integral accumulation term. The sliding mode operation module receives the target control command stream and switches the calculation path of the target control command stream to the sliding mode operation module. The sliding mode operation module calculates the sliding mode control quantity using the exponential reaching law and constrains the output amplitude range of the target control command stream through the sliding mode control quantity to limit the control gain divergence boundary. In order to eliminate the discontinuous control step caused by the transient of clearing the integral term and switching the calculation path, a dynamic smooth transition lock is set inside the sliding mode operation module. Its execution logic is as follows: At the moment when the DC bus current first touches 95% of the rated value, although the controller strips the original integral accumulation term, it does not directly clear the integral control quantity to zero. Instead, it uses the last integral accumulation algebraic sum latched in the current control cycle as a constant bias and seamlessly assigns it to the equivalent constant control term in the exponential reaching law of the sliding mode variable structure controller. During the 50-millisecond system transition dead zone, the output of the sliding mode variable structure controller is smoothly algebraically superimposed by this constant bias and the newly calculated exponential reaching term, forcibly constraining the abrupt change slope of the target control command flow to not exceed 3% per millisecond.

[0038] As the bus current gradually moves away from the 95% overload limit and converges towards the steady-state boundary under the constraint of the sliding mode control, the constant bias decreases linearly in the next three sampling periods according to a preset arithmetic progression until it reaches zero. This allows the control loop to smoothly evolve to the pure sliding mode variable structure control state in a non-abrupt manner, avoiding command chattering and mechanical shock in the transition blind zone. The proportional factor used to reduce the weight of each component in the dynamic feedback matrix control unit is calculated by a negative exponential power function of the natural constant base based on the absolute value of the state jump scalar in the current period. The attenuation coefficient of the negative exponential power function is tuned to the range of 0.05 to 0.15 according to the dynamic current overload margin of the power drive inverter. The proportional factor increases with the state jump scalar. The amplitude increases while monotonically decreasing; the sliding mode operation module in the anti-saturation dynamic feedback clamping unit uses the exponential approach law to calculate the sliding mode control quantity, and the exponential approach rate is set to a constant of 0.5. In the switching transient when the DC bus current reaches 95% of the rated operating current value, the dynamic smooth transition lock assigns the last integral cumulative algebraic sum latched in the current control cycle as a constant bias to the equivalent constant control term of the sliding mode operation module. In the following 50 milliseconds, this bias is algebraically superimposed with the newly calculated exponential approach term to limit the sudden change slope of the target control command flow to within 3% per millisecond. After 50 milliseconds, the control quantity decreases linearly to zero in an arithmetic progression for three consecutive sampling cycles, and the control flow smoothly transitions to the pure sliding mode variable structure control state.

[0039] Example 3: This example combines Figures 1 to 2 This document describes a closed-loop control system and method for aluminum extrusion molding, such as... Figure 1 As shown, step S1 uses the operating condition data synchronization unit to collect the DC bus current and current travel displacement of the power drive frequency converter. Step S2 uses the discrete state observation unit to perform discrete difference matrix operation on the DC bus current and current travel displacement to construct the resistance drift characteristic that characterizes the deformation resistance of the controlled aluminum material, and analyzes the state jump scalar based on the resistance drift characteristic. Step S3 uses the dynamic feedback matrix control unit to reduce the weight of each component of the control gain matrix according to the state jump scalar, and performs saturation clamping on the control gain matrix and outputs the target control command stream when the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold. Step S4 uses the anti-saturation dynamic feedback clamping unit to clear the integral accumulation term when the DC bus current reaches 95% of the rated operating current value, and switches the control path to sliding mode variable structure control, and constrains the output amplitude range of the target control command stream by outputting the sliding mode control quantity.

[0040] like Figure 2As shown, continuous feedback control flows to sliding mode variable structure control through three paths. The first path is when the resistance drift characteristic causes a jump, shutting down continuous feedback control and flowing to the cascaded control branch of the multi-layer state machine. When the DC bus current reaches 95% of the rated operating current, the control path switches to sliding mode variable structure control and merges into it. The second path is when the DC bus current reaches 95% of the rated operating current, clearing the integral accumulation term and directly merging into sliding mode variable structure control. The third path is when the transient current jump slope exceeds the rated safe change rate for three consecutive sampling periods, forcibly suspending the weight update chain of the discrete state observation unit and flowing to the segmented setpoint control mode. When the DC bus current reaches 95% of the rated operating current, the control path switches to sliding mode variable structure control and merges into it.

[0041] Example 4: The current operating condition data synchronization unit outputs time-aligned operating condition data according to a 10ms sampling period. The discrete state observation unit performs a second-order difference matrix transformation on the DC bus current to filter out high-frequency operating condition interference signals in the discrete logic space, extract the slip component reflecting the rheological state change trend of the aluminum material in the extrusion die, and determine the slip component as the resistance drift characteristic. The specific implementation steps of the second-order difference matrix transformation are as follows: After the discrete state observation unit obtains the current first-order difference value of the DC bus current in the current cycle, it performs an algebraic subtraction with the previous first-order difference value cached in the previous control cycle to calculate the second-order difference rate of change of the current. This second-order difference rate of change is substituted into a preset time-domain discrete low-pass filter operator. This low-pass filter operator adopts a third-order moving average window structure to perform a weighted average operation on the second-order difference values ​​of three consecutive cycles, thereby directly filtering out the strong current caused by the high-frequency switching of the frequency converter in the digital logic space without relying on physical capacitor hardware. The magnetic interference signal; the current variation residual sequence extracted after this digital filtering can accurately correspond to the micro-flow shear stress step of the aluminum lattice at the mold exit. This high-purity digital residual characteristic is defined as the slip component. When performing objective characterization and test procedure judgment, if the sign of the slip component reverses within two consecutive cycles and the absolute value exceeds 10 amperes per square millisecond, it is confirmed that the aluminum material is in an unstable nonlinear rheological state. Based on this, the system directly determines it as the resistance drift characteristic of the current cycle, which is used to trigger the flow of subsequent adaptive control modes. The working condition data synchronization unit, discrete state observation unit, dynamic feedback matrix control unit and anti-saturation dynamic feedback clamping unit are respectively connected to the bus arbitration unit. The bus arbitration unit constructs a fixed priority communication architecture in the closed-loop control loop and sets the sliding mode control quantity output by the anti-saturation dynamic feedback clamping unit to have the highest communication priority, directly covering the target control command flow output by the dynamic feedback matrix control unit.

[0042] The entire system is housed within a distributed industrial control chassis. The operating condition data synchronization unit, discrete state observation unit, dynamic feedback matrix control unit, anti-saturation dynamic feedback clamping unit, and bus arbitration unit are interconnected with an external power drive inverter via a shielded industrial Ethernet bus. The system sends the target control command stream to the power drive inverter in real time. During the operation of the aluminum extrusion forming closed-loop control method, the operating condition data synchronization unit collects the DC bus current and current travel displacement of the power drive inverter. The discrete state observation unit performs discrete difference matrix operations on the DC bus current and current travel displacement to construct a characterization of the controlled aluminum... The resistance drift characteristics of the material deformation resistance are analyzed, and the state jump scalar is derived based on the resistance drift characteristics. The dynamic feedback matrix control unit adjusts the weight of each component of the control gain matrix according to the state jump scalar. When the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold, the control gain matrix is ​​saturated and clamped, and the target control command stream is output. The anti-saturation dynamic feedback clamping unit clears the integral accumulation term and switches the control path to sliding mode variable structure control when the DC bus current reaches 95% of the rated operating current value. The output amplitude range of the target control command stream is constrained by the output sliding mode control quantity.

[0043] Example 5: The current system is set up inside a distributed industrial control chassis and interconnected with an external power drive inverter via a shielded industrial Ethernet bus. The sampling pulse generator generates a synchronous sampling trigger signal according to a 10ms sampling period. The synchronous buffer memory writes the DC bus current and the current travel displacement in parallel at the control moment corresponding to each sampling trigger signal, so that the DC bus current and the current travel displacement in the same control cycle form time-aligned operating condition data and inputs it into the discrete state observation unit. The discrete state observation unit reads the time-aligned operating condition data according to the time order of adjacent sampling cycles, performs discrete difference matrix operations on the DC bus current and the current travel displacement, and performs a second-order difference matrix transformation on the DC bus current to filter out high-frequency operating condition interference signals in the discrete logic space, extracts the slip component reflecting the rheological state change trend of the aluminum material in the extrusion die, and analyzes the state jump scalar after determining the slip component as the resistance drift characteristic. In the above physical evolution process, the energy dissipation caused by the lattice slip inside the controlled aluminum material at the microscale will directly cause the macroscopic mechanical extrusion resistance on the die contact surface to deflect instantaneously.

[0044] Because the main drive shaft of the extruder is rigidly mechanically coupled to the power bus of the variable frequency drive inverter, the deflection of this macroscopic resistance is reversed and applied to the rotor of the drive motor through the transmission linkage. This causes the electromagnetic torque required by the motor to overcome the load to undergo a coordinated abrupt change within 1 millisecond, which is directly reflected as a step fluctuation in the characteristic quantity of the DC bus current of the frequency converter. This invention directly collects this DC bus current and the current travel displacement. Since the transmission and collection of electrical characteristics eliminates the medium heat conduction or material strain wave propagation time required by traditional temperature or mechanical stress sensors, its response speed is at the microsecond level, thus constructing a direct observation path without signal delay within the controller. Through this high-speed transmission and data mapping of microscopic lattice deformation mechanical quantities to macroscopic electrical quantities, the feedback loop can use this electrical abrupt change to calculate the counter-offsetting command in advance before the large time delay of mechanical transmission is fully manifested, thereby eliminating the phase misalignment between the control action and the physical state.

[0045] After the state transition scalar output is sent to the dynamic feedback matrix control unit, multiple discrete state layers correspond to cascaded control branches through their monotonically bound unique memory address index values. When the resistance drift characteristic changes, continuous feedback control is turned off and cascaded control branches are activated. The dynamic feedback matrix control unit calculates the monotonically decreasing component based on the polarity and amplitude of the state transition scalar and reduces the weights of each dimension of the control gain matrix. When the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold, the control gain matrix is ​​saturated and clamped before the target control command stream is output. The feedforward hysteresis damping compensation unit extracts the historical reverse control residual and corrects the output slope of the target control command stream online based on the historical reverse control residual, thus fine-tuning the output slope. After the range constraint is within 0.8 to 1.2 times the reference output slope, it is sent to the anti-saturation dynamic feedback clamping unit. The anti-saturation dynamic feedback clamping unit continuously monitors the DC bus current. When the DC bus current reaches 95% of the rated operating current value, the integral cut-off module clears the integral accumulation term. The sliding mode calculation module receives the target control command stream and switches the control path to sliding mode variable structure control. The sliding mode calculation module uses the exponential reaching law to calculate the sliding mode control quantity. The bus arbitration unit sets the sliding mode control quantity as the highest communication priority in the fixed priority communication architecture and directly overrides the target control command stream output by the dynamic feedback matrix control unit, so that the power drive inverter receives the target control command stream after the output amplitude range is constrained by the sliding mode control quantity.

[0046] Example 6: Under the same aluminum extrusion molding verification condition, the rated operating current value of the power drive inverter is used as the detection reference for the DC bus current. The operating condition data synchronization unit collects the DC bus current and the current travel displacement according to a sampling period of 10ms. The synchronization buffer memory outputs the timing-aligned operating condition data under the same sampling trigger signal. The distributed industrial control chassis sends the target control command stream to the power drive inverter through the shielded industrial Ethernet bus. The verification group adopts a combination configuration of operating condition data synchronization unit, discrete state observation unit, dynamic feedback matrix control unit, feedforward hysteresis damping compensation unit, anti-saturation dynamic feedback clamping unit and bus arbitration unit. The comparison group maintains the same DC bus current acquisition conditions, current travel displacement acquisition conditions and 10ms sampling period, and maintains a continuous feedback control path before the DC bus current reaches 95% of the rated operating current value. The DC bus current, current travel displacement, state jump scalar and the output state of the target control command stream are recorded in each control cycle.

[0047] When the DC bus current changes within a continuous sampling period, the discrete state observation unit performs discrete difference matrix operations on the time-aligned operating condition data and performs a second-order difference matrix transformation on the DC bus current to filter out high-frequency operating condition interference signals. It extracts the slip component reflecting the rheological state change trend of the aluminum material within the extrusion die and determines it as the resistance drift characteristic. The dynamic feedback matrix control unit, based on the state jump scalar analyzed from the resistance drift characteristic, shuts down the continuous feedback control and activates the cascaded control branch of the multi-layer state machine. This ensures that the weights of each dimension of the control gain matrix are monotonically reduced before the target control command stream is output. To eliminate the fundamental difference in physical dimensions between current and displacement parameters, a unified normalized bridging interface is configured in the system before performing discrete difference matrix operations. Specifically, the discrete state observation unit obtains the original increment of the DC bus current and the original increment of the current travel displacement for the current cycle, and calls the preset rated operating current value and maximum rated travel value in the memory as the reference denominator, respectively. Then, the original current increment is divided by the rated operating current value to obtain the dimensionless relative rate of change of current, and the original displacement increment is divided by the maximum rated travel value to obtain the dimensionless... The relative rate of change of displacement; through this transformation, the originally incompatible units of ampere and meter are completely separated and unified into pure digital quantities between 0 and 1. This enables the two physical parameters to have the operational basis for digital matrix fusion and algebraic superposition under the same logical dimension, eliminating the limitation that cross-dimensional data cannot be directly calculated. The feedforward hysteresis damping compensation unit extracts historical reverse control residuals and corrects the output slope of the target control command flow online, constraining the fine-tuning range of the output slope to within 0.8 to 1.2 times the baseline output slope, and records the target control command under different output slope fine-tuning ranges. The output slope of the command flow changes and its corresponding state with the current travel displacement change. When the DC bus current reaches 95% of the rated operating current value, the integral cut-off module clears the integral accumulation term. The sliding mode calculation module switches the calculation path of the target control command flow to sliding mode variable structure control and uses the exponential approach law to calculate the sliding mode control quantity. The bus arbitration unit sets the sliding mode control quantity as the highest communication priority in the fixed priority communication architecture and directly covers the target control command flow output by the dynamic feedback matrix control unit, so that the power drive inverter receives the target control command flow after the output amplitude range is constrained by the sliding mode control quantity.

[0048] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the present invention.

[0049] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

Claims

1. A closed-loop control system for aluminum extrusion molding, characterized in that the system... include: The operating data synchronization unit is used to collect the DC bus current and current travel displacement of the power drive frequency converter; The discrete state observation unit, connected to the working condition data synchronization unit, is used to perform discrete difference matrix operations on the received DC bus current and the current travel displacement to construct the resistance drift characteristics that characterize the deformation resistance of the controlled aluminum material, and to analyze the state jump scalar based on the resistance drift characteristics. The dynamic feedback matrix control unit is connected to the discrete state observation unit. It is used to reduce the weights of each component of the control gain matrix according to the state jump scalar, and to saturate and clamp the control gain matrix and output the target control command stream when the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold. The anti-saturation dynamic feedback clamping unit, connected to the dynamic feedback matrix control unit, is used to clear the integral accumulation term when the DC bus current reaches 95% of the rated operating current value, and switch the control path to sliding mode variable structure control. It constrains the output amplitude range of the target regulation command flow by outputting the sliding mode control quantity.

2. The closed-loop control system for aluminum extrusion molding according to claim 1, characterized in that, The system also includes a feedforward hysteresis damping compensation unit; the feedforward hysteresis damping compensation unit is connected to the dynamic feedback matrix control unit and is used to extract historical reverse control residuals and correct the output slope of the target control command flow online; the dynamic feedback matrix control unit has a built-in multi-layer state machine containing multiple discrete state layers, each discrete state layer is monotonically bound to a unique memory address index value, which is used to shut down continuous feedback control and activate the cascaded control branch of the multi-layer state machine when the drag drift characteristics change abruptly.

3. The closed-loop control system for aluminum extrusion molding according to claim 1, characterized in that, The operating condition data synchronization unit includes a sampling pulse generator and a synchronization buffer memory; The operating condition data synchronization unit generates a 10ms sampling period through a sampling pulse generator and uses a synchronous buffer memory to capture the DC bus current and the current travel displacement in parallel, and outputs operating condition data with timing alignment.

4. The closed-loop control system for aluminum extrusion molding according to claim 2, characterized in that, When the dynamic feedback matrix control unit activates the cascaded control branch of the multi-level state machine, it calculates the monotonically decreasing component based on the polarity and magnitude of the state transition scalar, and reduces the weight of each dimension of the control gain matrix according to the monotonically decreasing component, thus completing the gain oversaturation clamping before the target control command stream is output to the power drive inverter.

5. The closed-loop control system for aluminum extrusion molding according to claim 1, characterized in that, The anti-saturation dynamic feedback clamping unit includes an integral cut-off module and a sliding mode calculation module. When the DC bus current reaches 95% of the rated operating current, the anti-saturation dynamic feedback clamping unit clears the integral accumulation term through the integral cut-off module and switches the calculation path of the target control command flow to the sliding mode calculation module to calculate the sliding mode control quantity using the exponential reaching law and limit the control gain divergence boundary.

6. The closed-loop control system for aluminum extrusion molding according to claim 2, characterized in that, The feedforward hysteresis damping compensation unit limits the fine-tuning range of the output slope of the target control command stream, confining it to 0.8 to 1.2 times the reference output slope, in order to reduce the phase lag of the target control command stream.

7. The closed-loop control system for aluminum extrusion molding according to claim 1, characterized in that, The discrete state observation unit is used to perform second-order difference matrix transformation on the DC bus current in order to filter out high-frequency operating condition interference signals in the discrete logic space, extract the slip component that reflects the rheological state change trend of aluminum material in the extrusion die, and determine the slip component as the resistance drift characteristic.

8. The closed-loop control system for aluminum extrusion molding according to claim 1, characterized in that, The system also includes a bus arbitration unit; the bus arbitration unit is connected to the operating condition data synchronization unit, the discrete state observation unit, the dynamic feedback matrix control unit and the anti-saturation dynamic feedback clamping unit respectively, and is used to construct a fixed priority communication architecture in the closed-loop control loop, and set the sliding mode control quantity output by the anti-saturation dynamic feedback clamping unit to have the highest communication priority, directly covering the target control command stream output by the dynamic feedback matrix control unit.

9. The closed-loop control system for aluminum extrusion molding according to claim 1, characterized in that, The system is housed within a distributed industrial control chassis and interconnected with an external power drive inverter via a shielded industrial Ethernet bus, sending the calculated target control command stream to the power drive inverter in real time.

10. A closed-loop control method for aluminum extrusion molding, used to operate the closed-loop control system for aluminum extrusion molding as described in claim 1, characterized in that, Includes the following steps: Step S1: Use the operating condition data synchronization unit to collect the DC bus current and current travel displacement of the power drive frequency converter; Step S2: Use the discrete state observation unit to perform discrete difference matrix operation on the DC bus current and the current travel displacement to construct the resistance drift characteristics that characterize the deformation resistance of the controlled aluminum material, and analyze the state jump scalar based on the resistance drift characteristics. Step S3: The dynamic feedback matrix control unit adjusts the weights of each component of the control gain matrix according to the state jump scalar, and when the absolute value of the difference between adjacent sampling periods of the DC bus current exceeds the discrete noise filtering threshold, the control gain matrix is ​​saturated and clamped and the target control command stream is output. Step S4: When the DC bus current reaches 95% of the rated operating current value, the integral accumulation term is cleared using the anti-saturation dynamic feedback clamping unit, and the control path is switched to sliding mode variable structure control. The output amplitude range of the target regulation command stream is constrained by the output sliding mode control quantity.

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