Method for precise control of start phase deviation of continuous press line based on wet clutch
By predicting and correcting the clutch early start angle of the press using a linear regression model, the phase angle deviation problem during the start-up phase of the wet clutch was solved, thus improving the stability and failure rate of the continuous stamping line.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- TIANJIN C E ELECTRICAL AUTOMATION CO LTD
- Filing Date
- 2023-11-14
- Publication Date
- 2026-07-24
Smart Images
Figure CN117325502B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of stamping control technology, specifically relating to a precise control method for the starting phase deviation of a continuous stamping line based on a wet clutch. Background Technology
[0002] Continuous stamping lines are high-end products in automated press production lines. Due to their extremely high production efficiency, they are generally used in high-speed automated stamping production lines in the automotive industry. A continuous stamping line mainly consists of automated transfer devices and presses. Automated transfer devices refer to the automated equipment installed before and after the presses, responsible for transferring sheet metal; these are typically composed of robots or robotic arms. The presses in a continuous stamping line can be servo presses or mechanical presses based on wet clutches. Multiple presses are usually connected in series to form multiple stamping processes.
[0003] Currently, continuous stamping lines based on wet clutches are widely used in existing technologies. For the press control system, the core control objective is to maintain synchronous operation of multiple press slides with a constant angular difference (generally referred to as phase difference in the industry). There are several known methods for clutch control and press synchronization control:
[0004] JP2003284951A proposes a control method suitable for synchronous operation of tandem mechanical presses. It primarily proposes dynamically adjusting the speed of the press spindle by monitoring the phase difference between the presses, thereby reducing the problem of increasing phase angle deviation caused by press deceleration due to changes in forming load and other factors during operation. Furthermore, considering the differences in the inertia of the slide, drive mechanism, mold, and main motor capacity of each press, the time it takes for the press spindle to start and reach the predetermined speed will certainly differ. Therefore, a method is proposed to stagger the start-up time by a fixed time td (td being the start-up time difference).
[0005] KR20110058669A describes a continuous operating system for a production line. It is primarily applicable to stamping production lines with multiple units. It proposes maintaining a certain phase difference between each stamping unit for continuous operation, thereby improving production efficiency. It also proposes a method to reduce deviations during operation by adjusting the motor speed using a frequency converter.
[0006] US19830540355A describes a clutch and brake device for presses, punches, etc. Friction clutches / brakes, similar to those described therein, are most commonly used in existing stamping lines and are currently standard equipment on continuous stamping lines.
[0007] US20070523558A describes a method for controlling a wet clutch system. It primarily proposes controlling the brake or outputting diagnostic signals by monitoring clutch system pressure and brake trigger signals. This is mainly used to determine whether the brake's pre-adjustment distance exceeds a safe range and can be used to guide adjustments to this distance, thereby achieving a reliable clutch condition. The purpose of the diagnostics is primarily to identify the impact of problems in the hydraulic connection, such as leaks, air inclusions, elasticity changes, or temperature fluctuations, on the brake's braking effect, preventing premature clutch damage.
[0008] US20080680169A discloses an apparatus and method for reducing press angle control errors caused by variations in press load and preventing changes in the press load of one press from affecting another. The main function is to equip each press with a press angle reference value output unit to output a press angle reference value. A press command unit outputs a command speed value to the motor of the corresponding press based on the press angle reference value and the press angle detection value. The drive unit controls the speed correction unit of the corresponding press motor to correct the command speed value or the press angle reference value based on the command speed value, ensuring that the difference between the angle reference value and the actual angle of each press is within a predetermined value.
[0009] By combining currently known control methods, adjusting the speed setpoint of the main motor of the press during operation can reduce the phase angle deviation (the error between the actual and setpoint values of the angle deviation between presses) during continuous stamping line operation. In fact, in many cases, excessive phase angle deviation between presses in a continuous stamping line is not solely due to load or other variable factors during operation. The phase angle deviation may reach its maximum limit when the wet clutch is activated, leading to abnormal equipment shutdown.
[0010] Among the currently known control methods, there is no mention of how to solve the problem of excessive phase angle deviation caused during the clutch start-up phase. They all only propose setting an initial value or set value so that the subsequent press can operate according to this set value. Summary of the Invention
[0011] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a precise control method for the starting phase deviation of a continuous stamping line based on a wet clutch. This method is used in a continuous stamping line consisting of multiple mechanical presses connected in series. A pre-fitted linear regression model is used to predict the clutch advance angle of each press, thereby achieving precise control of the press phase angle deviation during the starting phase of the continuous stamping line.
[0012] This invention is achieved through the following technical solution:
[0013] A precise control method for the starting phase deviation of a continuous stamping line based on a wet clutch includes the following steps:
[0014] Step 1: Collect actual press start-up data from the continuous stamping line; each data set includes: clutch advance start angle, start-up interval time, clutch temperature / clutch oil tank temperature, etc. Among them, the clutch advance start angle refers to the angle of action required for the press to go from a standstill to the end of the start-up phase, which is fed back by the angle encoder installed on the press and calculated by the press control PLC; the start-up interval time refers to the time elapsed from the last complete stop of the press to the current start-up.
[0015] Step 2: Construct a linear regression model using the data from Step 1; the model equation is y = ax1 + bx2 + k, where y is the clutch pre-start angle, x1 is the start interval time, x2 is the clutch temperature / clutch oil tank temperature, and a, b, and k are the parameters to be fitted.
[0016] Step 3: Use the model obtained in Step 2 to predict the clutch advance start angle y of the press, and then use this prediction to correct the clutch advance start angle A of the press. The set phase difference between the slide position angle of this press and its preceding press.
[0017] In the above technical solution, the number of data sets collected in step one should be no less than 300.
[0018] In the above technical solution, the clutch temperature is read by a temperature sensor installed on the clutch bearing or body.
[0019] In the above technical solution, the clutch hydraulic oil temperature is obtained by reading a temperature sensor installed on the clutch hydraulic oil tank.
[0020] In the above technical solution, after predicting the clutch pre-start angle of each press, the present invention uses a limiter to control the output value of the above equation to ensure system stability. When the predicted value exceeds the upper and lower limits of the limiter, the allowed upper and lower limit values will be used instead of the predicted value. The limit value should be within the safe operating range of the equipment, for example, ±5°.
[0021] The advantages and beneficial effects of this invention are as follows:
[0022] This invention can significantly eliminate the premature clutch start-up angle deviation in presses caused by the unstable start-up time of wet clutches. Applying this invention to continuous stamping lines based on wet clutches can significantly reduce the phase angle deviation caused by the clutch start-up phase of the press, lower the failure rate during the start-up phase of the continuous stamping line, and improve system stability. Attached Figure Description
[0023] Figure 1 This is a speed curve diagram of the press during the startup phase.
[0024] Figure 2 This is a flowchart for constructing a linear regression model.
[0025] Figure 3 This is a flowchart of the model's usage.
[0026] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation
[0027] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below with reference to specific embodiments.
[0028] This embodiment designs a precise control method for the starting phase deviation of a continuous stamping line based on a wet clutch. Its basic principle is to use a pre-fitted linear regression model to predict the clutch advance start angle of each press in the continuous stamping line, thereby achieving precise control of the starting phase deviation. The starting phase deviation refers to the error value between the actual phase difference and the set phase difference between the slider positions of the current press and the preceding press during the starting phase of the continuous stamping line. The starting phase refers to the process of the press spindle accelerating from rest to the set speed after the clutch of the press receives the disengagement command, generally not exceeding 1 second. This speed is called the press speed, usually measured in stamping times per minute (spm). The speed curve of the press during the starting phase is shown below. Figure 1 As shown; the clutch early start angle of the press refers to the angle of motion required for the press to go from a standstill to the end of the start-up phase; the prediction of the clutch early start angle of each press refers to predicting the clutch early start angle of each press by using a pre-fitted linear regression model before each press is started.
[0029] The following describes in detail the precise control method for the starting phase deviation of a continuous stamping line based on a wet clutch, which includes the following steps:
[0030] Step 1: Collect the actual start-up data of the presses in the continuous stamping line.
[0031] Each data set includes: clutch pre-start angle, start interval time, clutch temperature / clutch oil tank temperature, etc. The clutch pre-start angle is fed back by an angle encoder installed on the press and calculated by the press control PLC; the start interval time refers to the time elapsed from the last complete stop of the press to the current start, in seconds; the clutch temperature can be read by a temperature sensor installed on the clutch bearing or body, and the clutch hydraulic oil temperature can be read by a temperature sensor installed on the clutch hydraulic oil tank. This invention preferentially uses clutch temperature.
[0032] The aforementioned data sets are used to fit the parameters of the model in step two. The more data sets and the wider the data range, the better the model's predictive performance. In practice, it is recommended to record no fewer than 300 data sets.
[0033] Step Two: Construct a linear regression model using the data from Step One. The process is as follows: Figure 2 As shown.
[0034] The model equation is y = ax1 + bx2 + k, where y is the clutch pre-start angle, x1 is the start interval time, x2 is the clutch temperature / clutch oil tank temperature, and a, b, and k are the parameters to be fitted. The model is fitted using linear regression with the press start data obtained in step one to obtain an accurate model, which is used to predict the clutch pre-start angle.
[0035] Step 3: Use the model obtained in Step 2 to predict the clutch start-up angle of the press.
[0036] The clutch advance angle y predicted by the model is used to correct the clutch advance angle A of the press. For example, the phase difference between the current press and its preceding press slide position angle is set to... At that time, the clutch of the press was engaged at an earlier angle. That is, the current press should start with the slide of its preceding press. Start after adjusting the angle to ensure synchronization. The model's usage flowchart is as follows: Figure 3 As shown.
[0037] Furthermore, after predicting the clutch pre-start angle of each press, this invention uses a limiter to control the output value of the above equation to ensure system stability. When the predicted value exceeds the upper and lower limits of the limiter, the allowed upper and lower limits will be used instead of the predicted value. The limit value should be within the safe operating range of the equipment, for example, ±5°.
[0038] The present invention has been described above by way of example. It should be noted that any simple modifications, alterations or other equivalent substitutions that can be made by those skilled in the art without creative effort without departing from the core of the present invention fall within the protection scope of the present invention.
Claims
1. A precise control method for the starting phase deviation of a continuous stamping line based on a wet clutch, characterized in that, Includes the following steps: Step 1: Collect actual press start-up data from the continuous stamping line; each data set includes: clutch advance start angle, start-up interval time, clutch temperature / clutch oil tank temperature, etc. Among them, the clutch advance start angle refers to the angle of action required for the press to go from a standstill to the end of the start-up phase, which is fed back by the angle encoder installed on the press and calculated by the press control PLC; the start-up interval time refers to the time elapsed from the last complete stop of the press to the current start-up. Step 2: Construct a linear regression model using the data from Step 1; the model equation is y=ax1+bx2+k, where y is the clutch pre-start angle, x1 is the start interval time, x2 is the clutch temperature / clutch oil tank temperature, and a, b, and k are the parameters to be fitted. Step 3: Use the model obtained in Step 2 to predict the clutch advance start angle y of the press and use it to correct the clutch advance start angle A of the press. A = φ - y, where φ is the set phase difference of the slider position angle of the current press relative to its predecessor press. After predicting the clutch start-up angle of the press, a limiter is used to control the output value of the above equation to ensure system stability. When the predicted value exceeds the upper and lower limits of the limiter, the allowed upper and lower limit values will be used instead of the predicted value.
2. The precise control method for the starting phase deviation of a continuous stamping line based on a wet clutch according to claim 1, characterized in that: The number of data sets collected in step one should be no less than 300.
3. The precise control method for the starting phase deviation of a continuous stamping line based on a wet clutch according to claim 1, characterized in that: The clutch temperature is read by a temperature sensor mounted on the clutch bearing or body.
4. The precise control method for the starting phase deviation of a continuous stamping line based on a wet clutch according to claim 1, characterized in that: The clutch hydraulic oil temperature is read by a temperature sensor installed on the clutch hydraulic oil tank.