Device parameter inverse operation solving method based on forward formula cycle approximation

Abstract

The application discloses a device parameter inverse operation solving method based on a forward formula cycle approximation, and is used for solving the problem that an operator cannot check real process values due to the fact that only forward calculation is available for industrial equipment and no inverse formula is available. The application automatically inversely solves real process parameters in a cycle trial calculation+forward formula approximation mode, and writes back to HMI display. The method does not need to provide an inverse formula by a manufacturer, does not modify equipment programs, has zero cost implementation, can be widely applied to various electromechanical equipment with only one-way calculation formula such as a disc shear, a rolling mill, a trimming shear and instrument conversion, and greatly improves on-site operability and production safety.

Description

Technical Field

[0001] This invention discloses a method for inverse calculation of equipment parameters based on forward formula cyclic approximation, addressing the problem that industrial equipment only has forward calculations and lacks inverse formulas, making it impossible for operators to view the actual process values. This invention automatically solves for the actual process parameters through cyclic trial calculations and forward formula approximation, and writes them back to the HMI display. This method requires no inverse formulas from the manufacturer, does not modify the equipment program, and is implemented at zero cost. It can be widely applied to various electromechanical equipment with only unidirectional calculation formulas, such as disc shears, rolling mills, edge trimming shears, and instrument conversion devices, significantly improving on-site operability and production safety. Background Technology

[0002] The following pain points are commonly found in equipment widely used in metallurgical production lines, such as shearing machines, disc shears, rolling mills, and deviation correction devices: The equipment control system only encapsulates forward calculation formulas (such as gap → angle, roll gap → position, thickness → current), but does not provide reverse derivation formulas (angle → gap, position → roll gap). Operators can only view intermediate physical quantities (angle, position, count) on the HMI (human-machine interface), and cannot intuitively obtain the real process values, so the operation relies on experience and judgment. Equipment manufacturers often refuse to provide reverse calculation functions, citing reasons such as the lack of inverse calculation source code and program encryption, leaving on-site maintenance personnel with no independent modification capabilities; The inability to directly verify process parameters can easily lead to product quality deviations, affecting production stability and finished product qualification rate.

[0003] Traditional solutions rely heavily on equipment manufacturers to provide reverse engineering formulas or customized modification programs. Without corresponding formulas, reverse engineering cannot be achieved. These solutions have extremely poor versatility, long modification cycles, high costs, and lack on-site self-rescue capabilities. Summary of the Invention

[0004] Purpose of the invention This paper presents a general method that does not rely on the manufacturer's inverse calculation formula, does not modify the original PLC program, and does not add hardware. It can solve the real process parameters from the forward formula by simply approximating the formula through software. Technical solution

[0005] Obtain the existing positive calculation formulas for the equipment (e.g., angle = F (clearance)) and clarify the correspondence between process values ​​and intermediate control quantities; Set the range of process values ​​to be traversed in the system (e.g., gap starts from 0.01mm and increases in increments of 0.001mm) and the accuracy threshold (e.g., 0.006mm). Starting from the minimum value, substitute it into the positive formula in a loop and calculate the corresponding theoretical intermediate control quantity (such as theoretical angle) one by one. Compare the theoretical intermediate control quantity with the intermediate control quantity (such as the actual angle) actually acquired by the PLC; When the difference between the two is less than the set precision threshold, the match is considered successful, and the currently substituted process value is the true value. Exit the loop and write back the calculated actual process values ​​to the PLC / HMI screen for display; The entire process is executed on a timed basis (e.g., once every 1 second) to achieve real-time reverse calculation of intermediate control quantities to process values.

[0006] Core Innovation Points It does not require manufacturers to provide inverse calculation formulas; it only relies on existing forward formulas to achieve inverse solutions through iterative approximation, thus completely eliminating dependence on external technologies. It requires zero hardware modification and no PLC program alteration, and is implemented solely through software algorithms, resulting in low implementation costs and strong compatibility. The accuracy can be freely set to adapt to the process requirements of different equipment; It has high computational efficiency and can complete accurate matching within seconds, meeting the needs of real-time display. Beneficial effects

[0007] This addresses the industry pain point of not being able to view the true process values ​​due to the lack of inverse calculation formulas, allowing operators to intuitively determine whether process parameters are qualified. No changes are required to existing equipment and procedures, implementation risk is zero, and it is compatible with various electromechanical equipment; It is highly versatile and can be widely used in scenarios such as disc shears, rolling mills, edge trimming shears, and instrument conversion. The accuracy is adjustable to meet the accuracy requirements of parameter display for different processes; It has low computational requirements, stable operation, and does not consume excessive system resources, making it suitable for long-term operation in industrial settings. Detailed Implementation

[0008] Obtain the forward formula from the equipment manufacturer, for example: Angle = Clearance × Coefficient (20) + Offset (0.5) (Unit: Angle °, Clearance mm); The PLC's current actual angle value (e.g., actual angle = 10.5°) is collected in real time via the communication interface. The system sets the process value (gap) traversal range to 0.01mm~5.0mm, with a step size of 0.001mm and an allowable error threshold of 0.006mm. Initiate a loop to solve: First cycle: Assuming gap = 0.01mm, substitute into the positive formula to calculate theoretical angle = 0.01×20+0.5=0.7°, the difference between this and the actual angle of 10.5° = 9.8° > threshold, continue; Iterative loop: Gradually increase the gap value, repeatedly calculate the theoretical angle and compare the difference; Match successful: When the gap = 0.5mm, the theoretical angle = 0.5×20+0.5=10.5°, and the difference between the actual angle and the theoretical angle = 0≤th threshold, the gap value (0.5mm) is determined to be the true value; The system writes the actual gap value (0.5mm) into the corresponding register of the PLC, and the HMI screen simultaneously displays: angle (original value: 10.5°) + gap (inverse calculation result: 0.5mm); Operators can visually view the actual gap value through the HMI to determine whether it meets the process requirements (such as the standard gap of 0.45-0.55mm), eliminating the need for blind operation.

Claims

1. A method for solving equipment parameters by inverse operation based on forward formula cyclic approximation, characterized in that, Includes the following steps: (1) Obtain the existing forward calculation formula of the equipment, which is used to calculate intermediate control quantities from process values; (2) Real-time acquisition of actual intermediate control quantities output by PLC, including angle, position, and count; (3) Starting from the set minimum value, the process values ​​are iterated in small steps and substituted into the positive formula one by one to calculate the theoretical control quantity. (4) Compare the difference between the theoretical control quantity and the actual control quantity. When the difference is less than the set accuracy threshold, determine that the process value being traversed is the true process value. (5) Write back the actual process values ​​obtained from the solution to the PLC / HMI interface to realize the visualization of reverse parameters in scenarios without inverse calculation formulas.

2. The method according to claim 1, characterized in that, The process values ​​include disc shear gap, mill roll gap, thickness, width, pressure, and displacement; the intermediate control quantities include motor angle, position value, counter value, and analog output signal.

3. The method according to claim 1, characterized in that, The entire inverse calculation process does not modify the original PLC program, does not add any new hardware equipment, and does not require the equipment manufacturer to provide inverse calculation formulas. It relies purely on the software cyclic approximation algorithm to achieve the inverse calculation.