A control method for a hybrid injection molding machine

Abstract

The application relates to the technical field of injection molding machine control, and provides a control method of a hybrid power injection molding machine, which comprises an injection molding machine control system and two or more servo drivers; each servo driver can control two servo motors, the servo motors are mechanical transmission servo motors or hydraulic oil pump servo motors, each servo driver is internally provided with two independent encoder identification units for measuring the speed feedback and real-time rotating position angle of the servo motor; one servo driver is used for controlling two servo motors, the same main power input is shared, the electrical connection wiring input can be reduced, the production efficiency can be effectively improved, and the cost of the oil-electricity hybrid power injection molding machine is reduced to the maximum extent. In the control of mold opening and closing, the injection molding machine control system and the servo driver can be matched with occasions with various load characteristics.

Description

Technical Field

[0001] This invention relates to the field of injection molding machine control technology, and more specifically to a control method for a hybrid injection molding machine. Background Technology

[0002] Injection molding machines are mainly classified into traditional hydraulic injection molding machines, all-electric injection molding machines, and hybrid electric injection molding machines in terms of structure and control. Compared to the insufficient control precision of traditional hydraulic injection molding machines and the excessively high cost of all-electric injection molding machines, hybrid electric injection molding machines fall between the two, maximizing cost while meeting the requirements of high precision and low cost for different applications.

[0003] Currently, hybrid injection molding machines can be categorized by control method into two types: one uses a hydraulic pump to drive the mold clamping mechanism, while the other uses a screw and belt-driven electric motor for the injection unit; the other can be reversed, with the mold clamping mechanism using a screw and belt-driven electric motor and the injection unit using a hydraulic pump; or a hybrid control method can be selected based on logical actions, such as using a screw and belt-driven electric motor for mold opening / closing and injection / melting actions, while other logical actions are driven by a hydraulic pump. Regardless of the control method, servo control typically uses one servo driver for each servo motor. With multiple power sources, multiple servo drivers are needed to control the servo motors, resulting in higher costs. Furthermore, because hydraulic control and mechanical transmission control are two different structures, their control methods differ. The control methods used by the servo driver controlling the hydraulic pump and the injection molding machine's computer system are not interchangeable with those used for controlling mechanical transmissions. This is especially true for servo drivers, where the algorithms for hydraulic servo control differ significantly from those for mechanical screw transmission. Consequently, the servo controller needs to be adjusted according to the actual situation when controlling different power sources. Summary of the Invention

[0004] This invention proposes a control method for a hybrid injection molding machine, which effectively replaces the technical problems caused by the existing method of controlling a servo motor with a servo drive.

[0005] A control method for a hybrid injection molding machine designed for this purpose includes an injection molding machine control system and two or more servo drives. Each servo drive can control two servo motors, which are either mechanically driven servo motors or hydraulic pump servo motors. Each servo drive has two built-in independent encoder recognition units for measuring the speed feedback and real-time rotational position angle of the servo motors. The control method is as follows: Each servo drive is connected to the injection molding machine control system, enabling the injection molding machine control system to perform real-time data acquisition, parameter adjustment and logic control of the servo drives; Each servo driver switches to the corresponding algorithm according to the actual load of the servo driver to achieve control under different loads; two servo motors controlled by the same servo driver can be controlled by the injection molding machine control system to run independently or synchronously. During the mold opening and closing process, the injection molding machine control system sends the mold opening and closing endpoint and the actual position to the servo driver. The servo driver then calculates and sends the motor acceleration and deceleration time to the injection molding machine control system.

[0006] Each servo driver and the injection molding machine control system are equipped with an Ethercat communication interface, enabling the injection molding machine control system to control multiple servo drivers through the Ethercat communication protocol, thereby achieving hybrid control.

[0007] The control process of the injection molding machine control system for the load power is as follows: Each servo drive communicates with the injection molding machine control system via the Ethercat interface and sends the corresponding station number information. The injection molding machine control system sorts the station numbers to distinguish different servo drives. After each servo driver numbers the motor through the PG encoder card, it sends the relevant motor ID to the injection molding machine control system. The injection molding machine control system then performs the corresponding injection molding machine logic actions based on the different motor IDs. After the injection molding machine control system identifies the load that the servo motor actually needs to drive, it will internally convert the relevant parameters into instructions required by the servo driver. After receiving instructions from the injection molding machine control system, the servo driver drives the relevant servo motors to perform the actions of the injection molding machine.

[0008] The process by which the injection molding machine control system identifies the load power is as follows; The mechanically driven servo motor sends its rotational speed and rotational position angle parameters to the PG1 encoder acquisition card of the servo driver via a 23-bit absolute encoder. The hydraulic oil pump servo motor sends its rotational speed and rotational position angle motor parameters to the PG2 encoder acquisition card of the servo driver via a rotary encoder. The servo drive switches the relevant control method according to the data collected by two different PG encoders through an internal algorithm; the hydraulic oil pump servo motor uses a pressure closed-loop control method, and the mechanical transmission servo motor uses a mechanical transmission control method. The servo drive distinguishes the corresponding load power through two different PG encoders, assigns them numbers, and sends the relevant data to the injection molding machine control system.

[0009] By checking whether the servo motor records its rotation position angle when the power is off, the servo driver can determine the load type based on encoder feedback, and then invoke pressure closed-loop control or mechanical transmission control.

[0010] The control process for opening and closing the mold, driven by a hydraulic oil pump and servo motor, is as follows: The injection molding machine control system continuously detects the actual position during the mold opening and closing process, and sends pressure, speed, and the target end point and actual position of the mold opening and closing to the servo driver. After receiving data from the injection molding machine control system, the servo driver uses an algorithm to calculate the acceleration and deceleration of the servo motor based on the speed and target position, which is used to control the mold opening and closing action. At the same time, the acceleration and deceleration parameters are fed back to the injection molding machine control system. During the mold opening and closing process, the servo drive detects the actual position of the mold opening and closing. When the actual position is close to the target position, it will automatically enter the deceleration stage and send the relevant parameters to the injection molding machine control system.

[0011] When the mold is opened and closed by the hydraulic oil pump servo motor, the injection molding machine control system sends the speed required for the action to the servo driver. The servo driver converts the speed into rotation speed based on the calculation of the area of ​​the mold clamping cylinder. When the injection molding machine control system sends a start command, the servo driver accelerates by sending a set coefficient through the injection molding machine control system. In addition, during the control process of the mold opening endpoint, the injection molding machine control system sends the signal of the actual mold opening position to the servo driver. When there is a deviation between the target endpoint of the mold opening and the actual value, the servo driver causes the hydraulic oil pump servo motor to decelerate at the corresponding stroke position, so as to achieve the accuracy of the endpoint by adjusting the relevant deceleration position.

[0012] During the injection process, the injection molding machine control system sends synchronization instructions for the injection action and the forward movement of the injection unit to each servo driver. When each servo driver receives the synchronization instructions, it controls the servo motor of the relevant load, which drives the servo motor of the mechanical transmission and the servo motor of the hydraulic oil pump, so that the injection unit can also move forward synchronously when the injection action is working, avoiding the plastic from flowing out of the nozzle due to high injection pressure, and effectively preventing glue leakage.

[0013] The servo motor of the mechanical transmission is used to drive the lead screw or pulley, and the servo motor of the hydraulic oil pump is used to drive the hydraulic oil pump. During the injection molding process, the drawing action is driven by the lead screw, the melting action is driven by the pulley, and the remaining actions are driven by the oil pump. The control method includes the following steps. Step 1: Each servo drive sends its own station number to the injection molding machine control system via the Ethercat protocol, so that the injection molding machine control system can identify and distinguish different servo drives. Step 2: After the two PG encoder cards built into each servo driver identify the two servo motors, they number them and then convert the numbers into corresponding addresses, which are then sent to the injection molding machine control system via the Ethercat protocol. Step 3: The injection molding machine control system identifies the ID of each servo motor based on the obtained servo driver station number and servo motor PG encoder card number, and then controls each logic action accordingly. Step 4: When injection, extraction, melting, or hydraulic action parameters are input into the human-machine interface (HMI), the injection molding machine control system converts the corresponding parameters into instructions required by the servo drive. Step 5: The injection molding machine control system sends the converted parameters to the corresponding servo driver via the EtherCAT protocol, based on the identified servo motor. Step 6: Based on the instruction parameters obtained in Step 5, the corresponding servo driver uses the relevant load control method to drive the corresponding servo motor, so that the injection molding machine control system can control the corresponding logical actions. Step 7: The servo driver monitors the rotational position angle, speed and temperature of the servo motor in real time through the PG encoder card, and sends the working parameter information of the servo motor to the injection molding machine control system via the Ethercat protocol. Step 8: The injection molding machine control system will obtain the real-time working status of the servo motor based on the received data, and control the start and stop of each logic action.

[0014] The power of each servo motor is less than the power of the servo driver, so the injection and melting actions of the injection molding machine will not work simultaneously. At this time, the two servo motors do not run synchronously. If the mold opening and closing action and the melting action of the injection molding machine are performed simultaneously, when the actual load exceeds the rated power of the servo drive, the servo drive is allowed to operate under overload for a preset time, and the overload capacity is a predetermined percentage of the rated power; if the preset time is exceeded, the servo drive will alarm and stop all actions. If one of the servo motors controlled by the servo driver malfunctions, the servo driver will issue an alarm and stop operating.

[0015] The beneficial technical effects of the present invention are as follows: Compared with existing technologies, traditional servo control involves one servo drive controlling one servo motor. In this invention, one servo driver controls two servo motors, sharing the same main power input. This reduces electrical wiring and effectively improves production efficiency while minimizing the cost of hybrid electric injection molding machines. Furthermore, the coordination between the injection molding machine control system and the servo drive in mold opening and closing control allows for adaptation to various load characteristics, increasing the flexibility of practical applications. Attached Figure Description

[0016] Figure 1 This is a schematic diagram showing the coordination between the injection molding machine control system, servo driver, and various loads in an embodiment of the present invention.

[0017] Figure 2 This is a schematic diagram of the servo driver for different load control methods in an embodiment of the present invention.

[0018] Figure 3 This is a schematic diagram illustrating the switching control of different characteristic loads by the servo driver in an embodiment of the present invention.

[0019] Figure 4 This is a schematic diagram of the structure of the injection molding machine control system controlling the mold opening and closing actions in an embodiment of the present invention.

[0020] Figure 5 This is a schematic diagram of the structure of the injection molding machine control system in an embodiment of the present invention, which converts the corresponding motor parameters into logic control.

[0021] Figure 6 This is a schematic diagram of the acceleration process of the opening and closing mold algorithm servo control in an embodiment of the present invention.

[0022] Figure 7 This is a schematic diagram of the deceleration process of the opening and closing mold algorithm servo control in an embodiment of the present invention. Detailed Implementation

[0023] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. In order to make the above-mentioned objects, features and advantages of this application more apparent and understandable, many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0024] See Figures 1-7 A control method for a hybrid injection molding machine, wherein the hybrid injection molding machine includes an injection molding machine control system and two or more servo drives; each servo drive can control two servo motors, which are either mechanically driven servo motors or hydraulic pump servo motors; each servo drive has two built-in independent encoder recognition units for measuring the speed feedback and real-time rotational position angle of the servo motors; the control method is as follows: Each servo drive is connected to the injection molding machine control system, enabling the injection molding machine control system to perform real-time data acquisition, parameter adjustment and logic control of the servo drives; Each servo driver switches to the corresponding algorithm according to the actual load of the servo driver to achieve control under different loads; two servo motors controlled by the same servo driver can be controlled by the injection molding machine control system to run independently or synchronously. During the mold opening and closing process, the injection molding machine control system sends the mold opening and closing endpoint and the actual position to the servo driver. The servo driver then calculates and sends the motor acceleration and deceleration time to the injection molding machine control system.

[0025] By controlling two servo motors with a single servo driver, and adaptively switching between them via an internal algorithm, a single servo driver can simultaneously control the hydraulic pump and mechanical transmission, or two servo motors controlling either the hydraulic pump or the mechanical transmission. This control method reduces the number of servo drivers, adapts to different usage requirements, minimizes the cost of hybrid injection molding machines, and increases the flexibility of practical applications. During mold opening and closing, the injection molding machine control system sends the endpoint and actual position to the servo driver. The servo driver calculates the acceleration and deceleration times and sends them back, thus achieving precise control of mold opening and closing.

[0026] Each servo driver and the injection molding machine control system are equipped with an Ethercat communication interface, enabling the injection molding machine control system to control multiple servo drivers through the Ethercat communication protocol, thereby achieving hybrid control.

[0027] By setting up EtherCAT communication interfaces on both the injection molding machine control system and each servo drive, and using the EtherCAT communication protocol to control multiple servo drives, the real-time performance and synchronization of data transmission are significantly improved. EtherCAT communication features high speed and low latency, enabling the injection molding machine control system to simultaneously acquire operating data from multiple servo drives and quickly issue control commands, thereby achieving multi-axis collaborative control.

[0028] The control process of the injection molding machine control system for the load power is as follows: Each servo drive communicates with the injection molding machine control system via the Ethercat interface and sends the corresponding station number information. The injection molding machine control system sorts the station numbers to distinguish different servo drives. After each servo driver numbers the motor through the PG encoder card, it sends the relevant motor ID to the injection molding machine control system. The injection molding machine control system then performs the corresponding injection molding machine logic actions based on the different motor IDs. After the injection molding machine control system identifies the load that the servo motor actually needs to drive, it will internally convert the relevant parameters into instructions required by the servo driver. After receiving instructions from the injection molding machine control system, the servo driver drives the relevant servo motors to perform the actions of the injection molding machine.

[0029] The injection molding machine control system achieves orderly management of multiple servo drives and servo motors by controlling the load power. Specifically, each servo drive sends station number information through the EtherCAT interface, which the injection molding machine control system sorts to distinguish different drives. The servo drive assigns a motor ID to each motor via a PG encoder card, and the injection molding machine control system uses the motor ID to determine the corresponding logical action. After identifying the load, the system converts the parameters into the commands required by the drive, ultimately driving the servo motor to execute the action. This control process is logically clear and hierarchically structured, effectively avoiding confusion and conflicts in multi-motor control, and improving the system's manageability and control accuracy.

[0030] The process by which the injection molding machine control system identifies the load power is as follows; The mechanically driven servo motor sends its rotational speed and rotational position angle parameters to the PG1 encoder acquisition card of the servo driver via a 23-bit absolute encoder. The hydraulic oil pump servo motor sends its rotational speed and rotational position angle motor parameters to the PG2 encoder acquisition card of the servo driver via a rotary encoder. The servo drive switches the relevant control method according to the data collected by two different PG encoders through an internal algorithm; the hydraulic oil pump servo motor uses a pressure closed-loop control method, and the mechanical transmission servo motor uses a mechanical transmission control method. The servo drive distinguishes the corresponding load power through two different PG encoders, assigns them numbers, and sends the relevant data to the injection molding machine control system.

[0031] By identifying the load power in the injection molding machine control system, automatic identification and algorithm switching for different load types are achieved. Specifically, the servo motor of the mechanical drive sends parameters to the PG1 acquisition card via a 23-bit absolute encoder, while the servo motor of the hydraulic pump sends parameters to the PG2 acquisition card via a rotary encoder. Based on the data acquired by the two PG encoders, the servo driver automatically switches the corresponding control method using an internal algorithm; that is, the hydraulic pump uses pressure closed-loop control, and the mechanical drive uses mechanical drive control. This identification process is highly automated and can match the control method according to the actual load type, thereby improving the control adaptability of the injection molding machine.

[0032] By checking whether the servo motor records its rotation position angle when the power is off, the servo driver can determine the load type based on encoder feedback, and then invoke pressure closed-loop control or mechanical transmission control.

[0033] By utilizing the encoder's ability to record the servo motor's rotational angle when power is off, the servo drive can quickly determine the load type based on encoder feedback, and then automatically invoke pressure closed-loop control or mechanical transmission control. Specifically, the encoder on the mechanical transmission load side has a lithium battery and records the motor angle when power is off, used to calculate the actual position of the lead screw; the encoder on the hydraulic pump load side does not have a lithium battery. This load identification method based on the encoder's power-off memory function is simple in structure, reliable in judgment, and can achieve accurate identification of load type without additional sensors, further simplifying the system structure and reducing manufacturing costs.

[0034] In this embodiment, the encoder controlling the "mechanical transmission (lead screw)" has a lithium battery on one side. This battery records the actual position angle of the motor when power is off, and then sends the data to the injection molding machine computer (injection molding machine control system) to calculate the actual position of the lead screw. The encoder controlling the "pressure closed loop (hydraulic pump)" does not require power off to record the actual position angle of the motor, so it does not have a lithium battery on one side.

[0035] The control process for opening and closing the mold, driven by a hydraulic oil pump and servo motor, is as follows: The injection molding machine control system continuously detects the actual position during the mold opening and closing process, and sends pressure, speed, and the target end point and actual position of the mold opening and closing to the servo driver. After receiving data from the injection molding machine control system, the servo driver uses an algorithm to calculate the acceleration and deceleration of the servo motor based on the speed and target position, which is used to control the mold opening and closing action. At the same time, the acceleration and deceleration parameters are fed back to the injection molding machine control system. During the mold opening and closing process, the servo drive detects the actual position of the mold opening and closing. When the actual position is close to the target position, it will automatically enter the deceleration stage and send the relevant parameters to the injection molding machine control system.

[0036] When the mold is opened and closed by the hydraulic oil pump servo motor, the injection molding machine control system sends the speed required for the action to the servo driver. The servo driver converts the speed into rotation speed based on the calculation of the area of ​​the mold clamping cylinder. When the injection molding machine control system sends a start command, the servo driver accelerates by sending a set coefficient through the injection molding machine control system. In addition, during the control process of the mold opening endpoint, the injection molding machine control system sends the signal of the actual mold opening position to the servo driver. When there is a deviation between the target endpoint of the mold opening and the actual value, the servo driver causes the hydraulic oil pump servo motor to decelerate at the corresponding stroke position, so as to achieve the accuracy of the endpoint by adjusting the relevant deceleration position.

[0037] During the mold opening and closing process driven by the hydraulic pump servo motor, the injection molding machine control system monitors the actual position in real time and synchronously sends pressure, speed, target endpoint, and actual position data to the servo driver. Upon receiving the data, the servo driver calculates the motor's acceleration and deceleration parameters using an algorithm to control the mold opening and closing actions, and feeds these parameters back to the injection molding machine control system. When the actual position approaches the target position, the system automatically enters the deceleration phase. This control method achieves real-time position monitoring and intelligent deceleration during the mold opening and closing process, effectively avoiding overshoot and significantly improving the positioning accuracy and repeatability of the mold opening and closing, achieving a control level approaching that of a lead screw drive.

[0038] When the hydraulic pump servo motor drives the mold opening and closing, the injection molding machine control system sends a speed command to the servo driver. The servo driver converts the speed into motor speed based on the area of ​​the clamping cylinder and accelerates the motor using a set coefficient upon receiving the start command. In the mold opening endpoint control, the injection molding machine control system sends the actual mold opening position signal to the servo driver. When there is a deviation between the target endpoint and the actual value, the servo driver controls the motor to decelerate at the corresponding stroke position, achieving accurate stopping at the endpoint by adjusting the deceleration position. This technical solution effectively solves the problem of inaccurate mold opening and closing endpoint positioning, achieving smooth control of the acceleration and deceleration process and precise correction of the endpoint position.

[0039] During the injection process, the injection molding machine control system sends synchronization instructions for the injection action and the forward movement of the injection unit to each servo driver. When each servo driver receives the synchronization instructions, it controls the servo motor of the relevant load, which drives the servo motor of the mechanical transmission and the servo motor of the hydraulic oil pump, so that the injection unit can also move forward synchronously when the injection action is working, avoiding the plastic from flowing out of the nozzle due to high injection pressure, and effectively preventing glue leakage.

[0040] See Figure 3 To effectively prevent plastic from leaking from the nozzle during injection due to high injection pressure, the injection molding machine control system sends synchronized operating commands for the injection and injection stage movement. Upon receiving the synchronization command, the servo driver drives the corresponding load's servo motor using hydraulic / mechanical transmission control methods, ensuring that the injection stage moves synchronously during injection, effectively preventing leakage. In this embodiment, since the injection and melting actions use the same servo driver, the injection stage movement is achieved by using a separate servo driver to drive the hydraulic pump. Because the servo driver can flexibly adapt to various load scenarios, the same servo driver can also be used to synchronously drive the injection and injection stage movements.

[0041] The servo motor of the mechanical transmission is used to drive the lead screw or pulley, and the servo motor of the hydraulic oil pump is used to drive the hydraulic oil pump. During the injection molding process, the drawing action is driven by the lead screw, the melting action is driven by the pulley, and the remaining actions are driven by the oil pump. The control method includes the following steps. Step 1: Each servo drive sends its own station number to the injection molding machine control system via the Ethercat protocol, so that the injection molding machine control system can identify and distinguish different servo drives. Step 2: After the two PG encoder cards built into each servo driver identify the two servo motors, they number them and then convert the numbers into corresponding addresses, which are then sent to the injection molding machine control system via the Ethercat protocol. Step 3: The injection molding machine control system identifies the ID of each servo motor based on the obtained servo driver station number and servo motor PG encoder card number, and then controls each logic action accordingly. Step 4: When injection, extraction, melting, or hydraulic action parameters are input into the human-machine interface (HMI), the injection molding machine control system converts the corresponding parameters into instructions required by the servo drive. Step 5: The injection molding machine control system sends the converted parameters to the corresponding servo driver via the EtherCAT protocol, based on the identified servo motor. Step 6: Based on the instruction parameters obtained in Step 5, the corresponding servo driver uses the relevant load control method to drive the corresponding servo motor, so that the injection molding machine control system can control the corresponding logical actions. Step 7: The servo driver monitors the rotational position angle, speed and temperature of the servo motor in real time through the PG encoder card, and sends the working parameter information of the servo motor to the injection molding machine control system via the Ethercat protocol. Step 8: The injection molding machine control system will obtain the real-time working status of the servo motor based on the received data, and control the start and stop of each logic action.

[0042] See Figure 4The injection molding machine control system sends pressure, speed, and the target endpoint for mold opening and closing to the servo driver. Upon receiving the data, the servo driver uses an algorithm to calculate the acceleration and deceleration of the servo motor based on the speed and target position. During the mold opening and closing process, the injection molding machine control system continuously monitors the actual position and sends this position to the servo driver. When the servo driver receives the start command for mold opening and closing, it starts the servo motor according to the acceleration coefficient, ensuring a smooth start. When the actual position approaches the target position, it automatically enters the deceleration phase to ensure timely stopping of the mold opening and closing. All relevant parameters during this control process are sent to the injection molding machine control system, which then coordinates with other actuators, such as solenoid valves, to open and close the mold opening and closing actions based on these parameters. This control method achieves high positioning and repeatability accuracy in mold opening and closing, approaching the level of a lead screw drive.

[0043] The power of each servo motor is less than the power of the servo driver, so the injection and melting actions of the injection molding machine will not work simultaneously. At this time, the two servo motors do not run synchronously. If the mold opening and closing action and the melting action of the injection molding machine are performed simultaneously, when the actual load exceeds the rated power of the servo drive, the servo drive is allowed to operate under overload for a preset time, and the overload capacity is a predetermined percentage of the rated power; if the preset time is exceeded, the servo drive will alarm and stop all actions. If one of the servo motors controlled by the servo drive malfunctions, the servo drive will issue an alarm and stop operating. The servo drive itself has safety protection against short circuits, overcurrent, undervoltage, and phase loss, and also has a STO (Safety Toll Collection) function.

[0044] In this embodiment, the servo driver is selected based on the servo motor with the highest power. Application Case 1: The injection (lead screw) motor power is 32kW, and the melting (pulley) motor power is 18kW. Therefore, the selected servo driver must be greater than 32kW. Application Case 2: The hydraulic pump motor power is 32kW (for mold opening / closing, ejector pin, etc.), and the melting (pulley) motor power is 18kW. The selected servo driver is 37kW. If the mold opening / closing action and the melting action are performed simultaneously, and the actual load exceeds the servo driver's rated power, the servo driver is allowed to operate beyond its rated value. Generally, 150% of its rated value can be allowed to run for 60 seconds, which basically meets the needs of the injection molding machine. If 150% of its rated value is allowed to exceed 60 seconds, the servo driver will issue an alarm and stop operating.

[0045] The aforementioned servo drives serve as the primary driving source for the two servo motors. Each servo drive integrates two encoder recognition units, mainly used to read information such as the rotation angle, actual speed, and motor temperature of the servo motors. It uses a single main power input and two power source outputs to drive the two servo motors, and internally includes two sets of motor control algorithms for simultaneously or independently driving the servo motors. The injection molding machine control system, after recognizing the load characteristics through the servo drives, converts the parameters input from the HMI (Human Machine Interface) into the commands required by the servo drives and sends them to the servo drives. This allows the servo drives to control the servo motors to drive loads with different characteristics, such as oil pumps or lead screws.

[0046] In this embodiment, the injection molding machine control system includes a control circuit board, electrical components such as chips mounted on the control circuit board, etc.

[0047] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A control method for a hybrid injection molding machine, the hybrid injection molding machine comprising an injection molding machine control system, characterized in that: It also includes two or more servo drives; each servo drive can control two servo motors, which are either mechanically driven servo motors or hydraulic pump servo motors. Each servo drive has two built-in independent encoder recognition units for measuring the speed feedback and real-time rotational position angle of the servo motors; its control method is as follows: Each servo drive is connected to the injection molding machine control system, enabling the injection molding machine control system to perform real-time data acquisition, parameter adjustment and logic control of the servo drives; Each servo driver switches to the corresponding algorithm according to the actual load of the servo driver to achieve control under different loads; two servo motors controlled by the same servo driver can be controlled by the injection molding machine control system to run independently or synchronously. During the mold opening and closing process, the injection molding machine control system sends the mold opening and closing endpoint and the actual position to the servo driver. The servo driver then calculates and sends the motor acceleration and deceleration time to the injection molding machine control system.

2. The control method for a hybrid injection molding machine according to claim 1, characterized in that: Each servo driver and the injection molding machine control system are equipped with an Ethercat communication interface, enabling the injection molding machine control system to control multiple servo drivers through the Ethercat communication protocol, thereby achieving hybrid control.

3. The control method for a hybrid injection molding machine according to claim 1, characterized in that: The control process of the injection molding machine control system for the load power is as follows: Each servo drive communicates with the injection molding machine control system via the Ethercat interface and sends the corresponding station number information. The injection molding machine control system sorts the station numbers to distinguish different servo drives. After each servo driver numbers the motor through the PG encoder card, it sends the relevant motor ID to the injection molding machine control system. The injection molding machine control system then performs the corresponding injection molding machine logic actions based on the different motor IDs. After the injection molding machine control system identifies the load that the servo motor actually needs to drive, it will internally convert the relevant parameters into instructions required by the servo driver. After receiving instructions from the injection molding machine control system, the servo driver drives the relevant servo motors to perform the actions of the injection molding machine.

4. The control method for a hybrid injection molding machine according to claim 1, characterized in that: The process by which the injection molding machine control system identifies the load power is as follows; The mechanically driven servo motor sends its rotational speed and rotational position angle parameters to the PG1 encoder acquisition card of the servo driver via a 23-bit absolute encoder. The hydraulic oil pump servo motor sends its rotational speed and rotational position angle motor parameters to the PG2 encoder acquisition card of the servo driver via a rotary encoder. The servo drive switches the relevant control method according to the data collected by two different PG encoders through an internal algorithm; the hydraulic oil pump servo motor uses a pressure closed-loop control method, and the mechanical transmission servo motor uses a mechanical transmission control method. The servo drive distinguishes the corresponding load power through two different PG encoders, assigns them numbers, and sends the relevant data to the injection molding machine control system.

5. The control method for a hybrid injection molding machine according to claim 4, characterized in that: By checking whether the servo motor records its rotation position angle when the power is off, the servo driver can determine the load type based on encoder feedback, and then invoke pressure closed-loop control or mechanical transmission control.

6. The control method for a hybrid injection molding machine according to claim 1, characterized in that: The control process for opening and closing the mold, driven by a hydraulic oil pump and servo motor, is as follows: The injection molding machine control system continuously detects the actual position during the mold opening and closing process, and sends pressure, speed, and the target end point and actual position of the mold opening and closing to the servo driver. After receiving data from the injection molding machine control system, the servo driver uses an algorithm to calculate the acceleration and deceleration of the servo motor based on the speed and target position, which is used to control the mold opening and closing action. At the same time, the acceleration and deceleration parameters are fed back to the injection molding machine control system. During the mold opening and closing process, the servo drive detects the actual position of the mold opening and closing. When the actual position is close to the target position, it will automatically enter the deceleration stage and send the relevant parameters to the injection molding machine control system.

7. The control method for a hybrid injection molding machine according to claim 6, characterized in that: When the mold is opened and closed by the hydraulic oil pump servo motor, the injection molding machine control system sends the speed required for the action to the servo driver. The servo driver converts the speed into rotation speed based on the calculation of the area of ​​the mold clamping cylinder. When the injection molding machine control system sends a start command, the servo driver accelerates by sending a set coefficient through the injection molding machine control system. In addition, during the control process of the mold opening endpoint, the injection molding machine control system sends the signal of the actual mold opening position to the servo driver. When there is a deviation between the target endpoint of the mold opening and the actual value, the servo driver causes the hydraulic oil pump servo motor to decelerate at the corresponding stroke position, so as to achieve the accuracy of the endpoint by adjusting the relevant deceleration position.

8. The control method for a hybrid injection molding machine according to claim 1, characterized in that: During the injection process, the injection molding machine control system sends synchronization instructions for the injection action and the forward movement of the injection unit to each servo driver. When each servo driver receives the synchronization instructions, it controls the servo motor of the relevant load, which drives the servo motor of the mechanical transmission and the servo motor of the hydraulic oil pump, so that the injection unit can also move forward synchronously when the injection action is working, avoiding the plastic from flowing out of the nozzle due to high injection pressure, and effectively preventing glue leakage.

9. The control method for a hybrid injection molding machine according to claim 1, characterized in that: The servo motor of the mechanical transmission is used to drive the lead screw or pulley, and the servo motor of the hydraulic oil pump is used to drive the hydraulic oil pump. During the injection molding process, the drawing action is driven by the lead screw, the melting action is driven by the pulley, and the remaining actions are driven by the oil pump. The control method is as follows: Includes the following steps; Step 1: Each servo drive sends its own station number to the injection molding machine control system via the Ethercat protocol, so that the injection molding machine control system can identify and distinguish different servo drives. Step 2: After the two PG encoder cards built into each servo driver identify the two servo motors, they number them and then convert the numbers into corresponding addresses, which are then sent to the injection molding machine control system via the Ethercat protocol. Step 3: The injection molding machine control system identifies the ID of each servo motor based on the obtained servo driver station number and servo motor PG encoder card number, and then controls each logic action accordingly. Step 4: When injection, extraction, melting, or hydraulic action parameters are input into the human-machine interface (HMI), the injection molding machine control system converts the corresponding parameters into instructions required by the servo drive. Step 5: The injection molding machine control system sends the converted parameters to the corresponding servo driver via the EtherCAT protocol, based on the identified servo motor. Step 6: Based on the instruction parameters obtained in Step 5, the corresponding servo driver uses the relevant load control method to drive the corresponding servo motor, so that the injection molding machine control system can control the corresponding logical actions. Step 7: The servo driver monitors the rotational position angle, speed and temperature of the servo motor in real time through the PG encoder card, and sends the working parameter information of the servo motor to the injection molding machine control system via the Ethercat protocol. Step 8: The injection molding machine control system will obtain the real-time working status of the servo motor based on the received data, and control the start and stop of each logic action.

10. The control method for a hybrid injection molding machine according to claim 1, characterized in that: The power of each servo motor is less than the power of the servo driver, so the injection and melting actions of the injection molding machine will not work simultaneously. At this time, the two servo motors do not run synchronously. If the mold opening and closing action and the melting action of the injection molding machine are performed simultaneously, when the actual load exceeds the rated power of the servo drive, the servo drive is allowed to operate under overload for a preset time, and the overload capacity is a predetermined percentage of the rated power; if the preset time is exceeded, the servo drive will alarm and stop all actions. If one of the servo motors controlled by the servo driver malfunctions, the servo driver will issue an alarm and stop operating.

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