Power drive and control system for semi-physical simulation of numerical control machine tool

Abstract

The utility model discloses a power drive and control system for semi-physical simulation of a numerical control machine tool, which comprises a microcontroller, an Ethernet interface circuit, an encoder interface circuit, a current sampling module and an IGBT (Insulated Gate Bipolar Translator) module, the input end of the encoder interface circuit and the input end of the current sampling module are both connected with the output end of a torque motor, the output end of the encoder interface circuit and the output end of the current sampling module are both connected with the input end of the microcontroller, and the first output end of the microcontroller is connected with the input end of the IGBT module. The output end of the IGBT module is connected with the input end of the torque motor. The device can simulate the stress characteristics of each shaft of the numerical control machine tool in movement, improves the working efficiency of the system, reduces the material loss in the process, and can be widely applied to the technical field of development and manufacturing of numerical control systems.

Description

Technical Field

[0001] The utility model relates to the technical field of development and manufacturing of numerical control systems, in particular to a power drive and control system for semi-physical simulation of numerical control machine tools. Background Art

[0002] During the development of CNC systems, the functions and performance of CNC systems need to be verified. Currently, the commonly used method is to assemble the CNC system on the machine tool, process a batch of test samples of standard shapes, and then measure and map the samples to determine the functions and performance of the CNC system under actual working conditions. This method often has problems such as long verification cycle and high material waste. Utility Model Content

[0003] In order to solve the above technical problems, the purpose of the utility model is to provide a power drive and control system for semi-physical simulation of CNC machine tools, which can improve the work efficiency of CNC system performance verification.

[0004] The technical solution adopted by the utility model is:

[0005] A power drive and control system for semi-physical simulation of numerically controlled machine tools, comprising a microcontroller, an Ethernet interface circuit, an encoder interface circuit, a current sampling module and an IGBT module, wherein the Ethernet interface circuit is connected to the microcontroller, the input ends of the encoder interface circuit and the current sampling module are both connected to the output end of a torque motor, the output ends of the encoder interface circuit and the current sampling module are both connected to the input end of the microcontroller, the first output end of the microcontroller is connected to the input end of the IGBT module, and the output end of the IGBT module is connected to the input end of the torque motor.

[0006] Furthermore, the power drive and control system further comprises a synchronous rectification module, an input end of the synchronous rectification module is connected to the second output end of the microcontroller, and the synchronous rectification module is also connected to the IGBT module.

[0007] Furthermore, the power drive and control system also includes a voltage sampling module, the input end of the voltage sampling module is connected to the output end of the synchronous rectification module, and the output end of the voltage sampling module is connected to the input end of the microcontroller.

[0008] Furthermore, the power drive and control system also includes an energy-consuming braking module, and the energy-consuming braking module is connected to the synchronous rectification module.

[0009] Furthermore, the power drive and control system also includes a braking resistor, and an input end of the braking resistor is connected to an output end of the energy-consuming braking module.

[0010] Furthermore, the power drive and control system further comprises an isolation drive module, the input end of the isolation drive module is connected to the first output end of the microcontroller, and the output end of the isolation drive module is connected to the input end of the IGBT module.

[0011] Furthermore, the power drive and control system further comprises a rotary encoder, the rotary encoder is connected to the torque motor, and the output end of the rotary encoder is connected to the input end of the encoder interface circuit.

[0012] Furthermore, the IGBT module includes a plurality of IGBT tubes, one end of each of the IGBT tubes is connected to the synchronous rectification module, and the other end of each of the IGBT tubes is connected to the torque motor.

[0013] Furthermore, the Ethernet interface circuit includes an Ethernet chip, the microcontroller and the host computer are both connected to the Ethernet chip, and the Ethernet chip is a LAN8742A driver chip.

[0014] Furthermore, the microcontroller is a STM32F446 chip.

[0015] The beneficial effects of the utility model are as follows: it includes a microcontroller, an Ethernet interface circuit, an encoder interface circuit, a current sampling module and an IGBT module, the current of the torque motor is collected by the current sampling module, the rotation angle of the torque motor is collected by the encoder interface circuit, and then the rotation angle of the torque motor is converted into the position, speed and direction of the axis by the microcontroller, and the set torque and direction commands are sent to the microcontroller through the Ethernet interface circuit, and then the set torque is converted into a corresponding current by the microcontroller, and the converted current is compared with the collected current to obtain a current deviation value, and finally the microcontroller sends a PWM pulse to control the switching state of the IGBT module according to the current deviation value and the obtained current position and direction of the motor, and drives the torque motor to tend to the target value, thereby simulating the force characteristics of each axis of the CNC machine tool during movement, which can improve the work efficiency of the performance verification of the CNC system and reduce material loss. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A structural block diagram of a power drive and control system for semi-physical simulation of CNC machine tools provided by the utility model;

[0017] Figure 2 A circuit schematic diagram of the Ethernet interface circuit provided by the utility model;

[0018] Figure 3 A circuit schematic diagram of the encoder interface circuit provided by the utility model;

[0019] Figure 4The utility model is a schematic diagram of an application embodiment of a power drive and control system for semi-physical simulation of CNC machine tools.

[0020] Figure numerals: U70, Ethernet chip; CN70, socket; Y70, crystal resonator; C70-C77, first to eighth capacitors; R70, first resistor; R74-R79, second to seventh resistors; U50, signal transceiver; U51, first photocoupler; U52, second photocoupler; R50-R57, eighth to fifteenth resistors. DETAILED DESCRIPTION

[0021] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0022] During the development of CNC systems, the functions and performance of CNC systems need to be verified. Currently, the commonly used method is to assemble the CNC system on the machine tool, process a batch of test samples of standard shapes, and then measure and map the samples to determine the functions and performance of the CNC system under actual working conditions. This method often has problems such as long verification cycle and high material waste.

[0023] To this end, an embodiment of the utility model proposes a power drive and control system for semi-physical simulation of CNC machine tools, including a microcontroller, an Ethernet interface circuit, an encoder interface circuit, a current sampling module and an IGBT module. The current of the torque motor is collected through the current sampling module, and the rotation angle of the torque motor is collected through the encoder interface circuit. The microcontroller then converts the rotation angle of the torque motor into the position, speed and direction of the axis, and sends the set torque and direction commands to the microcontroller through the Ethernet interface circuit. The microcontroller then converts the set torque into a corresponding current, and compares the converted current with the collected current to obtain a current deviation value. Finally, the microcontroller sends PWM pulses according to the current deviation value and the obtained current position and direction of the motor to control the switching state of the IGBT module, and drives the torque motor toward the target value, thereby simulating the force characteristics of each axis of the CNC machine tool during motion, which can improve the work efficiency of CNC system performance verification and reduce material loss.

[0024] Reference Figure 1A power drive and control system for semi-physical simulation of CNC machine tools includes a microcontroller, an Ethernet interface circuit, an encoder interface circuit, a current sampling module and an IGBT module. The Ethernet interface circuit is connected to the microcontroller, the input ends of the encoder interface circuit and the current sampling module are both connected to the output end of the torque motor, the output ends of the encoder interface circuit and the current sampling module are both connected to the input end of the microcontroller, the first output end of the microcontroller is connected to the input end of the IGBT module, and the output end of the IGBT module is connected to the input end of the torque motor.

[0025] As a further optional implementation scheme, the microcontroller is a STM32F446 chip.

[0026] Specifically, the microcontroller is used to convert the rotation angle of the torque motor into the position, speed and direction of the shaft, and according to the torque and direction commands sent by Ethernet, convert the set torque into the corresponding current, and then compare the converted current with the collected current to obtain the current deviation value, and finally send PWM pulses to control the switching state of the IGBT module according to the current deviation value and the current angle and direction of the motor, so as to drive the torque motor toward the target value. It includes but is not limited to the STM32F446 chip, which has built-in peripherals such as MAC interface, GPIO interface, AD converter and TIM timer.

[0027] As a further optional implementation scheme, the Ethernet interface circuit includes an Ethernet chip, the microcontroller and the host computer are both connected to the Ethernet chip, and the Ethernet chip is a LAN8742A driver chip.

[0028] Specifically, refer to Figure 1 The Ethernet interface circuit is connected to the MAC peripheral of the microcontroller and the host computer. The Ethernet adopts the MODBUS / TCP protocol to send the set torque and direction commands to the microcontroller. Figure 2The circuit diagram of the Ethernet interface circuit is shown, in which the Ethernet chip U70 is an Ethernet physical layer driver chip, which can use but is not limited to a physical layer PHY transceiver with a model number of LAN8742A; the socket CN70 is a network socket with a network transformer, which can use but is not limited to a socket with a model number of HR911105A; the crystal resonator Y70 and the first capacitor C70 and the second capacitor C71 constitute an oscillator for providing a stable and accurate clock signal for the Ethernet chip U70; the first resistor R70 is a bias resistor; the third capacitor C72 and the fourth capacitor C73 are filter capacitors for internal voltage reduction; the second resistor R74, the third resistor R75, the fourth resistor R76, the fifth resistor R77 and the fifth capacitor C74, the sixth capacitor C75, the seventh capacitor C76, and the eighth capacitor C77 constitute a signal matching network for matching between different impedances to ensure that the signal can be effectively transmitted and reflected in the circuit; the sixth resistor R78 and the seventh resistor R79 are current limiting resistors of the light-emitting diode, which are used to prevent the light-emitting diode from burning out due to excessive current.

[0029] The encoder interface circuit is connected to the GPIO peripheral of the microcontroller to calculate the rotation angle of the torque motor according to the output value of the rotary encoder. The encoder interface adopts the RS422 standard and can be connected to the absolute rotary encoder of the BISS protocol. Figure 3 The circuit diagram of the encoder interface circuit is shown, in which the signal transceiver U50 is an RS422 signal transceiver, which is used to convert TTL level signals into differential drive signals and differential signals into TTL level signals, and can be used but not limited to the model MAX490; the first photocoupler U51 and the second photocoupler U52 are high-speed photocouplers, which are used to isolate interference signals on site to improve anti-interference ability, and can be used but not limited to the high-speed photocoupler TLP109; the eighth resistor R50 and the ninth resistor R51 are bias resistors of the input line; the tenth resistor R52 and the eleventh resistor R53 are terminal matching resistors, which are used for impedance matching to stabilize the circuit; the twelfth resistor R54 and the thirteenth resistor R55 are level pull-up resistors, which are used to protect the first photocoupler U51 and the second photocoupler U52; the fourteenth resistor R56 and the fifteenth resistor R57 are current limiting resistors, which are used to prevent the first photocoupler U51 and the second photocoupler U52 from burning out due to excessive current.

[0030] The current sampling module is connected to the output of the IGBT module and the ADC peripheral of the microcontroller to collect the current of the torque motor.

[0031] As a further optional implementation scheme, the IGBT module includes a plurality of IGBT tubes, one end of each IGBT tube is connected to the synchronous rectification module, and the other end of each IGBT tube is connected to the torque motor.

[0032] Specifically, the IGBT module can be composed of 6 IGBT tubes, which are used to convert the direct current output by the synchronous rectification module into alternating current to drive the motor, so that the motor tends to the target value and realizes torque motor drive.

[0033] Reference Figure 1 As an optional implementation scheme, the power drive and control system further includes a synchronous rectification module, the input end of the synchronous rectification module is connected to the second output end of the microcontroller, and the synchronous rectification module is also connected to the IGBT module.

[0034] Among them, the synchronous rectification module is connected with the three-phase AC power, the TIM8 peripheral of the microcontroller, the voltage acquisition module and the IGBT module, etc., and is used to convert the AC power sent by the three-phase AC power supply into DC power, and then transmit the DC power to the IGBT module through the DC bus.

[0035] Reference Figure 1 As an optional implementation scheme, the power drive and control system also includes a voltage sampling module, the input end of the voltage sampling module is connected to the output end of the synchronous rectification module, and the output end of the voltage sampling module is connected to the input end of the microcontroller.

[0036] The voltage sampling module is connected to the synchronous rectification module and the ADC peripheral of the microcontroller to monitor the voltage value on the DC bus in real time and compare the detected voltage value with the voltage value of the external power supply.

[0037] Reference Figure 1 As an optional implementation scheme, the power drive and control system includes an energy-consuming braking module, and the energy-consuming braking module is connected to the synchronous rectification module.

[0038] Reference Figure 1 As an optional implementation scheme, the power drive and control system also includes a braking resistor, and the input end of the braking resistor is connected to the output end of the energy-consuming braking module.

[0039] Among them, the energy-consuming braking module is connected to the DC bus of the synchronous rectification module and an external braking resistor is connected. When the torque motor is driven by the servo motor of the numerical control system to rotate and is in a power generation state, if the voltage sampling module detects that the voltage fed into the DC bus is higher than the external power supply, the TIM8 peripheral of the microcontroller sends a PWM pulse to the synchronous rectification module to feed the excess electric energy back to the grid; when the electric energy cannot be fed back to the grid, the energy-consuming braking module is turned on to consume the electric energy in the braking resistor.

[0040] The braking resistor acts as a load to dissipate this excess energy. In this way, the system can prevent the DC bus voltage from being too high, thereby protecting other circuit components from overvoltage damage.

[0041] Reference Figure 1 As an optional implementation scheme, the power drive and control system further includes an isolation drive module, the input end of the isolation drive module is connected to the first output end of the microcontroller, and the output end of the isolation drive module is connected to the input end of the IGBT module.

[0042] The output terminal of the microcontroller TIM1 peripheral is connected to the gate isolation drive module of the IGBT, and the isolation drive module is connected to the IGBT module for driving the switch state of the IGBT module.

[0043] Reference Figure 1 As an optional implementation scheme, the power drive and control system also includes a rotary encoder, the rotary encoder is connected to the torque motor, and the output end of the rotary encoder is connected to the input end of the encoder interface circuit.

[0044] Among them, the rotary encoder is used to measure and track the angular displacement (i.e. rotation angle) of the rotating shaft connected to the torque motor. The rotary encoder is usually mounted on the shaft of the motor and rotates as the motor rotates, thereby generating a series of electronic signals corresponding to the angular position of the shaft.

[0045] In summary, the specific working principle of a power drive and control system for semi-physical simulation of CNC machine tools of the utility model is as follows: a synchronous rectifier circuit converts the AC power sent by a three-phase AC power supply into DC power; the motor rotation angle sent by the rotary encoder is received through the encoder interface circuit, and converted by the microcontroller into the position, speed and direction of the axis, and sent to the host computer through the Ethernet interface circuit; after the host computer compares the preset trajectory and rules, it sends the set torque and direction commands to the microcontroller through the Ethernet interface circuit; the microcontroller converts the torque into the corresponding current, compares it with the motor current feedback from the current sampling module to obtain the current deviation value, and calculates the PWM pulse width sent by the TIM1 peripheral in combination with the current angle and direction of the motor; the PWM pulse controls the switching state of the IGBT module through the isolation drive module, and the IGBT module converts the DC power output by the synchronous rectifier module into the three-phase AC power for driving the torque motor, and makes the motor current tend to the target value. When the torque motor is driven by the servo motor of the CNC system to rotate and is in a power generation state, if the voltage sampling module detects that the voltage fed into the DC bus is higher than the external power supply, the TIM8 peripheral of the microcontroller sends a PWM pulse to the synchronous rectification module to feed the excess electric energy back to the grid; when the electric energy cannot be fed back to the grid, the energy-consuming braking module is turned on to consume the electric energy in the braking resistor.

[0046] like Figure 4The figure shows an application embodiment of the utility model, using multiple power drive and control systems to connect the X-axis, Y-axis, Z-axis and A-axis motors of the numerical control system. The specific working process of the power drive and control system is: connecting the axes of the numerical control system to the power drive and control system. The operator inputs the machine tool model, tool model, blank model, workpiece model and process model in the host computer, and operates the numerical control system to reach the workpiece coordinate zero point, and then sets the zero point of the simulated workpiece on the host computer, then calls out the workpiece program on the numerical control system, and starts the numerical control system to enter the automatic cycle. The host computer reads the current position, speed and direction of each axis of the numerical control system, and draws and records the trajectory path of the tool tip, then calculates the relative position of the tool and the virtual workpiece blank, calculates the cutting torque and direction according to the model, decomposes the torque and direction to each motion axis, and then sends the torque and direction setting values ​​of each axis to the corresponding power drive and control system. The power drive and control system drives the torque motor to generate the required torque. The host computer generates the contour of the workpiece being processed based on the tool tip position and the virtual workpiece blank model. Finally, the measured data and theoretical data are compared to determine the function and performance of the CNC system processing.

[0047] Compared with the existing CNC system performance verification device, the utility model has the following advantages:

[0048] 1. During the experimental verification, it is only necessary to connect the axes of the CNC system to be tested with the load motor of the power drive and control system. Under the command of the host computer, the power drive and control system can synchronously apply sudden or constant torque to each axis to simulate the force of each axis during the processing. At the same time, the position and speed of each axis are monitored and recorded in real time. By comparing the measured data with the theoretical data, the function and performance of the CNC system processing can be determined, which can improve the work efficiency of the CNC system performance verification, reduce the material loss of the trial processing workpiece, and save costs;

[0049] Second, the system test results can be reproduced, thus providing strong support for finding system errors and improving the overall system verification efficiency and reliability;

[0050] 3. Easy to disassemble and assemble, which can reduce the labor intensity of operators.

[0051] In the description of the present utility model, "several" means one or more, "more" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.

[0052] In the present invention, unless otherwise clearly specified and limited, the terms such as "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed 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 the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0053] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0054] The preferred embodiments of the present invention are specifically described above, but the present invention is not limited to the embodiments. Those skilled in the art may make various equivalent modifications or substitutions without violating the spirit of the present invention, and these equivalent modifications or substitutions are all included in the scope defined by the claims of this application.

Claims

1. A power drive and control system for semi-physical simulation of CNC machine tools, characterized in that: It includes a microcontroller, an Ethernet interface circuit, an encoder interface circuit, a current sampling module and an IGBT module. The Ethernet interface circuit is connected to the microcontroller, the input ends of the encoder interface circuit and the current sampling module are both connected to the output end of the torque motor, the output ends of the encoder interface circuit and the current sampling module are both connected to the input end of the microcontroller, the first output end of the microcontroller is connected to the input end of the IGBT module, and the output end of the IGBT module is connected to the input end of the torque motor.

2. The power drive and control system for semi-physical simulation of CNC machine tools according to claim 1, characterized in that: The power drive and control system further comprises a synchronous rectification module, an input end of the synchronous rectification module is connected to the second output end of the microcontroller, and the synchronous rectification module is also connected to the IGBT module.

3. The power drive and control system for semi-physical simulation of CNC machine tools according to claim 2, characterized in that: The power drive and control system further comprises a voltage sampling module, the input end of the voltage sampling module is connected to the output end of the synchronous rectification module, and the output end of the voltage sampling module is connected to the input end of the microcontroller.

4. The power drive and control system for semi-physical simulation of CNC machine tools according to claim 2, characterized in that: The power drive and control system further comprises an energy-consuming braking module, and the energy-consuming braking module is connected to the synchronous rectification module.

5. The power drive and control system for semi-physical simulation of CNC machine tools according to claim 4, characterized in that: The power drive and control system further comprises a braking resistor, an input end of which is connected to an output end of the energy-consuming braking module.

6. The power drive and control system for semi-physical simulation of CNC machine tools according to claim 1, characterized in that: The power drive and control system further comprises an isolation drive module, the input end of the isolation drive module is connected to the first output end of the microcontroller, and the output end of the isolation drive module is connected to the input end of the IGBT module.

7. The power drive and control system for semi-physical simulation of CNC machine tools according to claim 1, characterized in that: The power drive and control system further comprises a rotary encoder, which is connected to the torque motor, and an output end of the rotary encoder is connected to an input end of the encoder interface circuit.

8. The power drive and control system for semi-physical simulation of CNC machine tools according to claim 2, characterized in that: The IGBT module includes a plurality of IGBT tubes, one end of each of the IGBT tubes is connected to the synchronous rectification module, and the other end of each of the IGBT tubes is connected to the torque motor.

9. The power drive and control system for semi-physical simulation of CNC machine tools according to claim 1, characterized in that: The Ethernet interface circuit comprises an Ethernet chip, the microcontroller and the host computer are both connected to the Ethernet chip, and the Ethernet chip is a LAN8742A driver chip.

10. The power drive and control system for semi-physical simulation of numerically controlled machine tools according to claim 1, characterized in that: The microcontroller is a STM32F446 chip.

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