CN200954695Y - Computer Numerical Control Device for AC Servo Motor Directly Driven Crank Press - Google Patents

Abstract

The utility model relates to computer numerical control device for the crank press directly driven by a servomotor, comprising a flush-type process computer, a motion control interface module, a rotating transformer interface module, a digital output interface module, a digital input interface module and a man-machine interface module. The modules are respectively connected to the either-direction signal of the process computer. With the deployment of the computer and control software, a crank motion of the crank press is driven with the AC servomotor controlled by the motion control interface module through the servo driver. By the medium of the link rod, the sliding block is driven for a reciprocating motion, realizing a press working operation. Concurrently, the position of the crank motion is read in by the medium of the rotating transformer and interface module for the position display of the closed loop feedback.

Description

Computer Numerical Control Device for AC Servo Motor Directly Driven Crank Press

technical field

The utility model relates to numerical control machining, in particular to a computer numerical control device used for directly driving a crank press by a servo motor, which is a significant improvement on the driving technology and control of the crank press, which is a common equipment for pressure processing, and belongs to mechanical processing and computer field of automatic control.

Background technique

The press can produce metal parts closer to the final shape, which is more in line with the requirements of clean production and green production. Crank presses occupy a major position in sheet metal production and are the most researched and developed for new products. AC servo motor has the characteristics of high control precision, stable operation, constant output torque within its rated speed range, strong overload capacity, reliable control, maintenance-free, quick response, etc. It has basically replaced DC servo motor in the field of industrial control. Its strong overload capacity is especially suitable for the use characteristics of the instantaneous high torque output of the crank press, and it has naturally become the target of people's attention. In recent years, due to the successful development of high-power AC servo motors (for example, FUNAC and Yaskawa have produced a series of AC servo motors with a power of 150Kw), mechanical equipment driven by high-power servo motors has emerged as the times require, such as the world-renowned KOMATSU, AIDA, AMADA, AMINO, TOYO, Sumitomo, Nissei Resin and other companies have successively launched servo motor-driven presses, servo motor-driven bending machines, servo motor-driven injection molding machines and other equipment using this technology.

The servo motor directly drives the crank press, which uses a high-power servo motor to directly drive the crank of the press, so that it can complete complex motion rules and improve the use efficiency of the press. The crank press directly driven by the servo motor (servo press for short), It represents the development direction of the press. It can optimize the design of the slider movement curve according to the process requirements, improve the versatility and intelligence level of the press; adopt the position full closed loop control, improve the movement accuracy of the slider of the press; adjust the slider stroke according to the different workpieces, shorten the The cycle time improves the productivity of the press; there is no clutch and flywheel idling energy consumption, which saves energy by more than 30% compared with ordinary crank presses; special working characteristic curves can be designed to control the punch speed during punching, thereby reducing punching vibration And noise, improve the service life of the mold. The AC servo motor directly drives the computer control system of the crank press, which is the core of the servo press.

Contents of the invention

The purpose of the utility model is to better solve the control problem of the crank press directly driven by the AC servo motor, and provides a computer numerical control system for the crank press directly driven by the servo motor. The system makes the crank directly driven by the AC servo motor The press can complete various complex slider motion curves with high speed, high efficiency, high precision and low noise, and complete complex processes that ordinary crank presses cannot do.

In order to accomplish the above work, the utility model adopts the technical scheme as follows: a computer numerical control system for directly driving the crank press by an AC servo motor, equipped with an embedded industrial control computer, and is characterized in that it also includes: used for AC servo motor control Motion control interface module for crank position measurement, resolver interface module for crank position measurement, digital output interface module for lubrication and brake control and slider in-position prompt, digital input interface module for press working status detection and key operation And human-machine interface modules for LCD and touch screen, the above modules are respectively connected with the embedded

The two-way signal connection of the industrial control computer, under the scheduling of the computer and control software, through the input of the corresponding CNC machining program and operation instructions, the motion control interface module controls the crank movement of the crank press driven by the AC servo motor through the servo driver, and through the connecting rod Drive the slider to reciprocate to complete the pressure processing action. At the same time, the motion position of the crank is read through the resolver and its interface module for closed-loop feedback and position display.

The embedded industrial control computer is a single-board industrial computer, including PC104 bus, USB, and Ethernet interfaces. The operating system, numerical control program and processing data are stored in the CF card or external hard disk of the industrial computer;

The motion control interface module is composed of CPLD-based special motion control chip MCX312, bus driver chips 26LS31 and 26LS32 and other main components. The motor control signal of MCX312 is output after being differentially driven by 26LS31, and the differential input signal of the encoder is input after being driven by 26LS32. In order to ensure high anti-interference performance, the digital input and output part of the chip has a photoelectric isolation circuit, and the main photoelectric isolation chip is P181. This module sends rotation commands to external servo drives, connects encoder feedback signals, receives emergency stop signals, etc.

The resolver interface module is used to precisely measure the crank position. The module consists of a resolver interface chip AD2S83 and two parallel data interface chips 74LS245 to form a conversion and bus interface circuit, and an operational amplifier to form a sinusoidal signal generator. The sine signal is sent to the AD2S83 as a reference signal, and at the same time sent to the resolver as an excitation signal; the sine and cosine output signals of the resolver are also connected to the AD2S83 at the same time, and the AD2S83 converts the reference signal and the sine and cosine signals output by the transformer into 14-bit absolute parallel The digital output is read into the embedded industrial computer through the bus interface chip 74LS245, thereby completing the measurement of the crank position.

The digital input interface module is used for console button input (including inching, single, continuous mode switching, pre-control and two-hand start button, etc.) exception, etc.). Digital input signals also include multi-machine linkage start and stop input signals. The digital input module is composed of a decoding drive circuit composed of bus interface chips 74LS245 and 74LS02, and is connected to an external digital input signal through an isolation resistor. Together with the slider position indication signal in the digital output, it constitutes the connection signal of the pressure processing production line Group.

The digital output interface module is composed of logic circuit 74LS02, latch 74LS573, optocoupler, relay and so on. The digital output signal is latched by 74LS573, and the external relay is driven through the photoelectric coupling and triode to control the start and stop of the lubricating pump, brake, alarm, pneumatic pump, etc. of the press.

The man-machine interface interface module is composed of a touch screen connected through a serial interface and a liquid crystal connected with a special interface. Through the touch screen, input the NC program, select the existing NC curve or program, select the movement mode, modify the working parameters, and display the processing process in real time . The processing program, operation history and operating parameters can also be transmitted through the network interface, and the processing program can also be downloaded through the network;

The numerical control device adopts a two-layer structure. The upper layer is the interface and signal processing layer. It is mainly composed of an embedded industrial computer and various functional modules. The embedded industrial control computer completes the man-machine interface interface, real-time display, digital input and output, and rotary encoder reading. Into other peripheral functions, the lower layer is the motion control layer, which is composed of the motion control module and its core motion control chip, and the various motion control functions of the motor are completed by the motion control module and its core motion control chip.

The utility model has the advantages: 1) adopts an open system structure, designs a computer numerical control system of a servo press, is based on Windows and Linux operating systems, and has easy-to-learn software and convenient operation and maintenance. The maintenance cost of the control system hardware is greatly reduced. 2) The production and operation mode of the servo press is the same as that of the ordinary press. It adopts the safe operation mode with both hands, and the operator can use it without special training. 3) A two-layer control architecture is adopted. The embedded industrial computer completes the external work such as the system man-machine interface and working status detection, and the motion control module is responsible for the complex motion control process of the crank, which ensures the real-time and accuracy of motion control. It also ensures the intuitiveness of system operation. 4) With a variety of processing techniques and slider movement curves, the servo press has a variety of functions to meet the needs of different products. 5) It has memory functions such as equipment operation history, equipment status history, equipment processing history, etc., and can perform remote diagnosis through the Internet network. 6) The rotary transformer is used as the crank position measurement sensor, which has strong anti-interference ability.

Description of drawings

Figure 1 is a structural block diagram of a computer numerical control device for a servo press;

Fig. 2 is a working flow chart of the computer numerical control device of the servo press;

Fig. 3 is a transmission schematic diagram of a crank press directly driven by an AC servo motor;

Fig. 4 is a block diagram of the control structure of the servo motor driving the crank of the press;

Fig. 5 is a functional block diagram of an embedded industrial control computer;

Fig. 6 is a circuit diagram of the motion control module of the computer numerical control system of the servo press;

Fig. 7 is the resolver input interface module of the CNC system of the servo press;

Fig. 8 is the digital output module of the numerical control system of the servo press;

Fig. 9 is the digital input module of the numerical control system of the servo press;

Figure 10 is the PC104 bus interface of the motion control card of the computer numerical control system of the servo press.

Detailed ways

Referring to Figure 1, the AC servo motor directly drives the crank press control device based on computer teaching and control technology, including an embedded industrial control computer as the control core, a motion control interface module for AC servo motor control, and a crank position measurement The resolver interface module, the digital output interface module for lubrication and brake control and slider in-position indication, the digital input interface module for press working status detection and button operation, and the man-machine interface interface composed of LCD and touch screen module; the above modules are respectively connected with the embedded industrial control computer with two-way signals. Under the scheduling of the computer and control software, by inputting the corresponding NC machining program and operation instructions, the motion control interface module controls the AC servo motor to drive the crank pressure through the servo driver. The crank movement of the machine drives the slider to reciprocate through the connecting rod to complete the pressure processing action. At the same time, the motion position of the crank is read in through the resolver and its interface module for closed-loop feedback and position display. The control system can select the control program and parameters through the touch screen, and control the operation of the press through the operation buttons to achieve high-precision and low-noise control of the slider. The system stores a variety of slider running curves, the running process is graphically displayed, and the operation is intuitive and convenient. Its workflow is shown in Figure 2.

The object controlled by the numerical control device is a crank press directly driven by an AC servo motor. As shown in Figure 3, the crank of the press is driven by an AC servo motor (a1), that is, the AC servo motor drives the crank to rotate through a planetary gear reducer (a2), a small synchronous belt (a3), and a large synchronous belt (a4). , and then drive the slider (a7) to reciprocate through the connecting rod (a6). The numerical control system makes the slider move according to the predetermined movement curve by controlling the movement of the AC servo motor. The structural block diagram of the crank closed-loop control system is shown in Figure 4.

Each module completes its own tasks according to the following functional requirements, and finally implements the work control of the entire press through the coordination of the core processor. The specific functions of each module are as follows:

The core of the computer numerical control device is an embedded single-board industrial computer, which has PC104 bus, USB, Ethernet and other interfaces, and can run operating systems such as Dos, Windows, and Linux. The operating system, numerical control programs, and processing data are stored in the embedded industrial control. to the CF card of the computer or an external hard disk. Through the PC104 bus, interface modules such as motion control module, resolver interface module, digital input and output module, operation module, and working status detection module are expanded. Through the single-board industrial computer, the LCD display and touch screen are connected. (See Figure 5 for the block diagram of the device)

The motion control interface module is composed of CPLD-based special motion control chip MCX312, bus driver chips 26LS31 and 26LS32 and other main components. After the motor control signal of MCX312 is differentially driven by 26LS31, it sends pulses and rotation direction commands to the AC servo motor driver. The module has various acceleration and deceleration driving curves. The module also has a photoelectric encoder input interface, and the encoder differential input signal is driven by 26LS32 and then input to MCX312. The module has 24-bit logic and actual up and down counters, which can perform position closed-loop control. The module also has an emergency stop function interface, which can handle emergency events. The embedded industrial control computer sends servo control instructions to the motion control module to control the slider of the servo crank press to complete the predetermined movement. Its circuit is shown in Figure 6. Part2 in the figure is the connection line of the special motion control chip MCX312, and Part3 is the encoder input interface composed of the driver chip 26LS32. The emergency stop signal is introduced by EMG.

The resolver interface module is used to precisely measure the crank position. This module consists of the resolver interface chip AD2S83 and two parallel data interface chips 74LS245 to form the conversion and bus interface circuits, and the operational amplifier forms the sine signal generator, as shown in Figure 7. The sine signal is sent to the AD2S83 as a reference signal, and at the same time sent to the resolver as an excitation signal; the sine and cosine output signals of the resolver are also connected to the AD2S83 at the same time, and the AD2S83 converts the reference signal and the sine and cosine signals output by the transformer into 14-bit absolute parallel The digital output is read into the embedded industrial computer through the bus interface chip 74LS245, thereby completing the measurement of the crank position. In Figure 7, Part4 is the sine wave generating circuit composed of operational amplifiers, Part5 is the wiring diagram of resolver processing chip AD2S83, and Part6 is the corner position reading circuit. The values of R1~R8 and C1~C8 in the circuit are calculated according to the requirements of the processing chip and the working speed of the press.

The digital output interface module is composed of logic circuit 74LS02, latch 74LS573, optocoupler, relay and so on. The digital control output signal is latched by 74LS573, and the external relay is driven by photoelectric coupling isolation and triode, as shown in Figure 8. Then through the contactor to control the start and stop of the lubricating pump, brake, alarm, pneumatic pump, etc. of the press. The CNC system also provides full-process control of press braking and lubrication, improving the safety and precision of the press. The digital output interface also provides sound and light alarm function, which is used to warn the serious abnormal state of the system. The digital output interface also provides the up and down signal of the slider, which can be used as the interface signal of the stamping automatic line.

The digital input module is composed of 3 bus interface chips 74LS245 and 74LS02, which are connected to external digital input signals through isolation resistors, as shown in Figure 9. Console button input signal (including inching, single, continuous mode switching, pre-control and two-hand start button, etc.) The signal level is converted through the level conversion intermediate relay, and then connected to the corresponding bus interface chip 74LS245 through the isolation resistor. The button input signal is connected to two 74LS245 chips, and the status detection signal is connected to the third chip 74LS245. Digital input signals also include multi-machine linkage start and stop input signals. Together with the slider position indication signal in the digital output, it forms the connection signal group of the press processing line.

The man-machine interface interface module is composed of a touch screen connected through a serial interface and a liquid crystal connected with a special interface. Through the touch screen, input the NC program, select the existing NC curve or program, select the movement mode, modify the working parameters, and display the processing process in real time . The processing program, operation history and operating parameters can also be transmitted through the network interface, and the processing program can also be downloaded through the network; the system has a key operation interface module, so that all operations of the press can be completed through the embedded industrial computer, and the numerical control system can store all The key operation process provides a teaching control method for the operation of the press. The operation of the press complies with the same or higher safety regulations as ordinary presses.

All hardware modules are connected to the embedded single-board industrial computer through the PC104 bus. The bus interface circuit of the module circuit board is composed of main chips such as bus comparator 74LS688 and decoder 74LS138, as shown in Figure 10.

The AC servo motor directly drives the numerical control device of the crank press, which has the functions of operation history memory, machine failure state history memory, and processing history memory, etc., and can be retrieved or remotely diagnosed through the network interface;

It has slider position measurement and pressure measurement subsystems, which can accurately measure and display the slider position curve and pressure change curve during the processing process, providing guarantee for the optimization of product processing curves.

Work process of the present utility model is as follows:

Turn on the machine, initialize each input and output interface; reset the machine to the top dead point; read the position information of the resolver at the top dead point; self-check each safety device, and read the power-on information.

Enter the main screen, allow the operator to operate according to the authority, you can choose to write programs, modify programs, modify program parameters, etc.; you can also choose to modify the system working parameter settings, such as modifying the lubrication time interval, modifying the fault waiting time and alarm mode, etc.

Pre-lubrication, according to the set parameters, pre-lubrication before pressure processing.

Select the processing method, select the processing method (slider running curve) and parameters through the touch screen, and perform single or continuous processing, and you can choose the inching mode to work.

Through the console buttons, the servo press is controlled to carry out pressure processing according to the set method and parameters.

During the processing, the system continuously detects the alarm signals of the servo press’s lubrication, overload, grating and other safety devices. If there is any abnormality, it will automatically deal with it immediately and give an alarm.

Claims (3)

1. be used for the computer numerical control device that servomotor directly drives crank press, be provided with embedded industrial control computer, it is characterized in that also including: the motion interface module, the rotary transformer interface module, the digital output interface module, the digital input interface module, the user-machine interface module, above-mentioned module is connected with the industrial control computer two-way signaling respectively, under the scheduling of computer and control software, by importing corresponding nc program and operational order, export the crank-motion of servo-driver control AC servo machinery driving crank press to by the motion interface module, driving slide block by connecting rod moves reciprocatingly, simultaneously, the movement position of crank reads in by rotary transformer and interface module thereof, is used for closed loop feedback and position display.

2. computer numerical control device according to claim 1 is characterized in that:

Embedded industrial control computer is the veneer industrial computer, includes PC104 bus and USB, Ethernet interface, operating system, and numerical control program and process data are stored in the CF card or hard disk of industrial computer;

The motion interface module includes the special-purpose motion control chip MCX312 of CPLD, bus driver chip 26LS31 and 26LS32, the motor control signal of MCX312 is exported after the 26LS31 differential driving, the encoder differential input signal then drives the back input through 26LS32, the digital input of chip has photoelectric isolating circuit, this module sends rotate instruction to outside servo-driver, connect the encoder feedback signal, receive emergent stop signal, and have multiple acceleration and deceleration driving curve, set as required and call;

The rotary transformer interface module is formed conversion and bus interface circuit respectively by rotary transformer interface chip AD2S83 and 2 parallel data grabbing card chip 74LS245, and constitute sinusoidal signal generator by operational amplifier, sinusoidal signal is sent into AD2S83 as the reference signal, sends into rotary transformer as pumping signal simultaneously; And the sine of rotary transformer and cosine output signal also insert AD2S83 simultaneously, AD2S83 is converted to 14 absolute Parallel Digital amount outputs with the sine and cosine signal of reference signal, transformer output, 74LS245 reads in built-in industrial control machine through Bus Interface Chip, finishes the measurement of crank position thus;

The digital input interface module comprises that Bus Interface Chip 74LS245 and 74LS02 form decoder driver circuit, link to each other with the external digital input signal by isolation resistance, 74LS02 carries out logic function control, drive chip 74LS245 by EBI carries out external signal and reads in, be used for input of operating desk button and machine works status monitoring, digital input signals also comprises the multi-machine interaction starting and stops input signal, its slide position index signal in numeral output, the connection sets of signals of formation pressure processing production line;

The digital output interface module comprises logic circuit 74LS02, latch 74LS573, photoelectrical coupler, relay, carry out function control by 74LS02, digital output signal latchs through 74LS573, and drive the outside actuating of relay by photoelectricity coupling and triode, the starting of the lubricating pump of controlled pressure machine, brake, alarm, air driven pump etc. and stopping;

The user-machine interface module is made up of touch-screen and liquid crystal, by touch-screen input numerical control program, the existing numerical control curve of selection or program, selection motion mode, modification parameter; Liquid crystal is the display operation situation in real time, and machine process is shown in real time, and procedure, operation history and operational factor etc. can be transmitted by network interface, and procedure can also pass through network download.

3. computer numerical control device according to claim 1 and 2, it is characterized in that: numerical control device adopts double-layer structure, the upper strata is interface and signal processing layer, mainly form by built-in industrial control machine and various functional module, lower floor is the motion control layer, is made up of motion-control module and nucleus movement control chip thereof.

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