Four roller wheel motor load balance control method for stone slab multi-wire sawing equipment

Abstract

The application relates to a four-roller wheel motor load balance control method of a stone material large plate multi-wire cutting equipment, which comprises a PLC controller provided with a median value average filtering processing module and a slope module; one of a plurality of roller traction motors operates in a speed control mode, and the remaining roller traction motors operate in a torque control mode; the speed of the one roller traction motor is used as the contour speed of the remaining roller traction motors; the torque of the one roller traction motor is used as the torque input of the remaining roller traction motors; during the cutting process of the equipment, the actual speed of a main shaft motor is used as the maximum contour speed of a driven shaft motor; and the actual torque value of the main shaft motor is collected in real time, the median value average filtering processing module is used for processing, the output value is given through the slope module, and the output value is used as the torque input of the remaining three driven shaft motors, so that the four roller traction motors of the multi-wire cutting equipment reach load balance.

Description

Technical Field

[0001] This application relates to the field of motor load control technology for multi-wire cutting equipment, and in particular to a load balance control method for the four roller motor of a multi-wire cutting equipment for large stone slabs. Background Technology

[0002] The multi-wire cutting equipment for large stone slabs consists of four servo motors driving four rollers, which are interconnected via diamond cutting wire mesh during the cutting process. During operation, due to differences in roller diameter and friction systems between the cutting wire mesh and roller grooves, the load on the four roller drive motors becomes unbalanced. If the load distribution among the four motors is uneven or significantly different, and all motors are in a speed adjustment phase, it will cause mutual pulling between the cutting wire mesh and the traction motor, making it impossible to maintain stable cutting wire tension. In severe cases, this can lead to cutting wire breakage and overheating / overload alarms in the traction motors, resulting in unstable equipment operation and affecting cutting efficiency and finished product quality. Therefore, to ensure even load distribution, balanced output, and speed matching among the four roller traction motors during stone slab cutting, a load balancing control method needs to be introduced into the four roller speed control system.

[0003] Traditional multi-wire cutting roller load distribution control methods operate with all roller traction motors in speed control mode, coupled to a virtual spindle and following its speed. This method works by real-time acquisition of the actual torque of all roller traction motors, using the maximum torque of each axis as a benchmark. The difference between the actual torque of each axis and the benchmark torque is then calculated using a PI controller. The PI controller outputs a real-time control signal, which serves as the load balancing adjustment signal. This signal is converted into an electronic gear ratio between each axis and the virtual spindle to fine-tune the following speed of each motor, reducing the linear speed difference between the rollers and achieving uniform output and load balance among the roller traction motors.

[0004] Based on practical experience, traditional methods have shortcomings, and the structure also references... Figure 2As shown, if at a certain moment, the actual torque values ​​of roller motors 2 and 4 are higher than those of roller motors 1 and 3 (i.e., roller motors 2 and 4 are under heavier load), then the load balancing signal superimposed on roller motors 1 and 3 will increase their speed (absolute value), while the load balancing signal superimposed on the heavily loaded roller motors 2 and 4 will decrease their speed (absolute value). However, during the entire cutting process, the cutting line and the workpiece being cut cannot be exactly the same and are dynamically changing. The load conditions of the four roller motors are also constantly changing. For example, if at this moment the speed (absolute value) of roller motors 2 and 4 happens to have a decreasing trend (i.e., the load on roller motors 2 and 4 is becoming lighter), then the load balancing signals superimposed on the four roller motors at this moment will exacerbate this trend, making the load balancing effect worse. By using real-time monitoring software (InoProShop software) to monitor the actual torque values ​​of the four roller motors in real time, it can be observed that the phenomenon of each traction motor pulling on each other through the cutting wire mesh is obvious, resulting in large torque fluctuations of each traction motor, making it impossible to achieve load balance. In severe cases, motor overload and overvoltage may even occur. This load balancing method is not ideal. Summary of the Invention

[0005] In view of the above practical problems and the shortcomings of the existing technology, the main technical problem to be solved by the present invention is to provide a load balancing control method for a four-roller motor of a multi-wire cutting equipment for large stone slabs, which can solve the problems of multi-axis synchronous control and load balancing.

[0006] To solve the above-mentioned technical problems, this application provides a load balancing control method for a four-roller motor in a multi-wire cutting equipment for large stone slabs, adopting the following technical solution:

[0007] A load balancing control method for a four-roller motor of a multi-wire cutting equipment for large stone slabs, including a PLC control system, wherein the PLC control system includes a median average filtering module and a ramp module.

[0008] One of the roller traction motors operates in speed control mode, while the remaining roller traction motors operate in torque control mode.

[0009] The speed of one of the roller traction motors is used as the profile speed of the remaining roller traction motors.

[0010] The torque of one of the roller traction motors is used as the torque input of the remaining roller traction motors.

[0011] In a preferred embodiment, one of the roller traction motors includes a multi-turn absolute encoder, which reads the actual speed of the one of the roller traction motors and feeds it back to the PLC control system.

[0012] In a preferred embodiment, the actual speed of one of the roller traction motors is used as the maximum profile speed of the remaining roller traction motors.

[0013] In a preferred embodiment, the maximum profile speed is the maximum speed limit value of one of the roller traction motors operating in both forward and reverse directions, and does not exceed the maximum allowable operating speed of the motor.

[0014] In a preferred embodiment, the PLC control system acquires the actual torque of one of the roller traction motors in real time and inputs it to the median average filtering module;

[0015] The output value of the median average filtering module is given by the ramp module, and the output value of the ramp module is used as the torque input of the remaining roller traction motor.

[0016] In a preferred embodiment, the median average filtering module includes two preset values: the number of consecutive samples and the number of scan cycles.

[0017] In a preferred embodiment, the median average filtering processing module continuously samples and sorts the actual torque value of one of the roller traction motors collected in real time according to the preset value to obtain the average value as the output value.

[0018] In a preferred embodiment, the ramp module includes three preset values: maximum positive slope, maximum negative slope, and reference time.

[0019] In a preferred embodiment, the ramp module performs ramp processing on the input value obtained by the median average filtering module according to the preset value and then outputs it.

[0020] In a preferred embodiment, one of the roller traction motors includes a Hall element, which reads the actual torque of the roller traction motor and feeds it back to the PLC control system.

[0021] In summary, this application has the following beneficial effects:

[0022] 1. This invention further improves the load balancing control method among the four roller traction motors of a multi-wire cutting equipment. Using the load and maximum contour speed of one of the four roller traction motors as a benchmark, the loads and maximum contour speeds of the other three motors are continuously adjusted and controlled to ensure they always follow the load changes of the benchmark motor during the cutting process, achieving constant load balance among the four roller traction motors. In practical use, the load balancing control method of this invention achieves good load balancing effect among the four roller traction motors, simplifying the load balancing control method while significantly improving load performance, thus ensuring cutting efficiency and quality during the cutting process. Attached Figure Description

[0023] Figure 1 This is a schematic flowchart of a motor load balancing control method provided in an embodiment of the present invention.

[0024] Figure 2 A schematic diagram of the four-roller structure of the multi-wire cutting equipment provided in an embodiment of the present invention;

[0025] Figure 3 The network topology diagram of the four-roller control system for a multi-wire cutting equipment provided in an embodiment of the present invention.

[0026] Explanation of reference numerals in the attached drawings: 1. First roller; 2. Second roller; 3. Third roller; 4. Fourth roller; 5. Traction motor for the first roller; 6. Traction motor for the second roller; 7. Traction motor for the third roller; 8. Traction motor for the fourth roller; 9. Pay-off roller; 10. Take-up roller; 11. Cutting wire mesh; 12. Workpiece to be cut. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "top / bottom," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed", "equipped", "sleeved / connected", "connected", etc., should be interpreted broadly. For example, "connection" can be a wall-mounted connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood according to the specific circumstances.

[0030] The following is in conjunction with the appendix Figure 1 -3 provides further details regarding this application.

[0031] This application discloses a load balancing control method for a four-roller motor in a multi-wire cutting equipment for large stone slabs. As shown in the figure, the multi-wire cutting equipment for large stone slabs includes four rollers, namely a first roller 1, a second roller 2, a third roller 3, and a fourth roller 4; the four rollers are correspondingly equipped with a first roller traction motor 5, a second roller traction motor 6, a third roller traction motor 7, and a fourth roller traction motor 8.

[0032] Four rollers are wound with a cutting wire mesh 11 for cutting the workpiece 12 to be cut. The cutting wire mesh 11 is provided with a wire feeding roller 9 and a wire taking roller 10 on the left and right. The multi-wire cutting equipment for large stone slabs is driven by four traction motors, which drive the four rollers respectively. During the cutting of the stone block, the four rollers are connected to each other by the diamond cutting wire mesh 11, so that the cutting wire on the cutting wire mesh 11 maintains a certain tension, thereby achieving the function of cutting the workpiece 12 to be cut.

[0033] like Figure 2 The diagram shows the structure of the four rollers and traction motor device of the multi-wire cutting equipment provided in this embodiment of the invention. The four rollers are driven by four permanent magnet synchronous servo motors connected by rigid couplings. The cutting wire is led out by the feed roller 9, wound onto the four rollers to form a cutting wire mesh 11, and then introduced onto the take-up roller 10. The cutting wire mesh 11 is driven to rotate by the rollers, thus completing the workpiece cutting action.

[0034] Therefore, in order to ensure that the load distribution, output balance, and speed matching of the four roller traction motors are uniform during the stone cutting process, this invention provides a load balancing method among the four roller motors of a multi-wire cutting equipment.

[0035] In this embodiment of the invention, a multi-wire cutting equipment using four permanent magnet synchronous servo motors as the traction motors for the four rollers of a multi-wire cutting machine, and employing four sets of Huichuan SV660N servo drivers and one AM400 series general-purpose medium-sized PLC to form the traction motor servo control system, is used as an example to illustrate the method for implementing the load balancing function of the four roller traction motors in the multi-wire cutting equipment of the present invention. Furthermore, the PLC control system is programmed using InoProShop programming software, using various function blocks. The PLC control system includes a median average filtering processing module and a ramp module.

[0036] like Figure 1 The diagram shown is a schematic flow chart of a load balancing method among four roller motors in a multi-wire cutting equipment according to an embodiment of the present invention, including the following steps:

[0037] Step 101: Switch the control mode of each axis motor.

[0038] Specifically, one of the four roller traction motors is first used as the main shaft (hereinafter referred to as the main shaft motor), and the remaining three roller traction motors are used as driven shafts (hereinafter referred to as driven shaft motors). The main shaft motor is modified to SMC_Velocity (speed) control mode and the driven shaft motor is modified to SMC_Torque (torque) control mode through the SMC_SetControllerMode function block and the process data object PDO.

[0039] Step 102: Convert the cutting line speed setting into the spindle motor speed, and use it as the spindle motor speed input.

[0040] Step 103: The actual rotational speed (actual speed) of the main spindle motor is collected and used as the maximum profile speed input for the three driven shaft motors.

[0041] In step 103, specifically, during the equipment cutting process, the PLC controller reads the actual rotational speed value of the spindle motor collected by the 23-bit multi-turn absolute encoder installed on the spindle motor through the fieldbus, and uses the read actual rotational speed value of the spindle motor as the maximum profile speed input of the other three driven shaft motors through the process data object PDO.

[0042] The maximum profile speed is the maximum speed limit of the traction spindle motor in both forward and reverse directions, but it must never exceed the maximum allowable operating speed of the motor.

[0043] In contour speed mode, the PLC controller sends the actual rotational speed (actual speed) of the main spindle motor, including the target speed, acceleration, and deceleration, to the servo driver of the driven axis motor. Speed ​​adjustment is performed internally by the servo.

[0044] Step 104: The actual torque of the spindle motor is collected in real time, processed by the median average filtering module, and then given by the ramp module. The output value of the ramp module is used as the torque input of the remaining roller traction motor.

[0045] In step 104, specifically, the current of the roller traction motor is linearly related to its torque. Therefore, the change in the motor armature current during operation reflects the change in the motor torque. The PLC control system reads the motor armature current value collected by the Hall element installed on the main spindle motor through the fieldbus, and then performs proportional conversion to obtain the actual torque of the main spindle motor. After the actual torque of the main spindle motor is processed by the median average filtering module, and then passed through the ramp module, its output is used as the torque input of the other three driven shaft motors.

[0046] The median average filtering module includes two preset values: the number of consecutive samples and the number of scanning cycles. It continuously samples the actual torque value of the spindle motor collected in real time according to the preset parameters, sorts the data, removes the maximum and minimum values, takes the average value, and finally obtains the output value.

[0047] The ramp module includes three preset values: maximum positive ramp, maximum negative ramp, and reference time. It performs ramp processing on the input values ​​according to the preset parameters and outputs them as the real-time torque input for the other three driven shaft motors.

[0048] Figure 3 The network topology diagram of the four-roller control system for multi-wire cutting equipment provided in this embodiment of the invention is shown. Four roller motors are connected to four servo motor drivers through power lines and encoder cables. The four servo motor drivers are then connected to a PLC controller through a fieldbus, thus forming the four-roller control system for multi-wire cutting equipment.

[0049] The above are all preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A load balancing control method for a four-roller motor in a multi-wire cutting equipment for large stone slabs, including a PLC control system, characterized in that: The PLC control system includes a median average filtering module and a ramp module. One of the roller traction motors operates in speed control mode, while the remaining roller traction motors operate in torque control mode. The speed of one of the roller traction motors is used as the profile speed of the remaining roller traction motors. The torque of one of the roller traction motors is used as the torque input of the remaining roller traction motors; wherein, the PLC control system collects the actual torque of one of the roller traction motors in real time and inputs it to the median average filtering processing module; The output value of the median average filtering module is given by the ramp module, and the output value of the ramp module is used as the torque input of the remaining roller traction motors. The median average filtering module includes two preset values: the number of consecutive samples and the number of scan cycles. It continuously samples the actual torque value of the main spindle motor collected in real time according to the preset parameters, sorts the data, removes the maximum and minimum values, takes the average value, and finally obtains the output value. The ramp module includes three preset values: the maximum positive slope, the maximum negative slope, and the reference time. It ramps the input value according to the preset parameters and outputs it as the real-time torque input of the other three driven shaft motors.

2. The load balancing control method for the four-roller motor of the multi-wire cutting equipment for large stone slabs according to claim 1, characterized in that: One of the roller traction motors includes a multi-turn absolute encoder, which reads the actual speed of the roller traction motor and feeds it back to the PLC control system.

3. The load balancing control method for the four-roller motor of the multi-wire cutting equipment for large stone slabs according to claim 1, characterized in that: The actual speed of one of the roller traction motors is taken as the maximum profile speed of the remaining roller traction motors.

4. The load balancing control method for the four-roller motor of the multi-wire stone slab cutting equipment according to claim 3, characterized in that: The maximum profile speed is the maximum speed limit value of one of the roller traction motors in both forward and reverse operation, and does not exceed the maximum allowable operating speed of the motor.

5. The load balancing control method for the four-roller motor of the multi-wire stone slab cutting equipment according to claim 1, characterized in that: One of the roller traction motors includes a Hall element, which reads the actual torque of the roller traction motor and feeds it back to the PLC control system.

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