CN103439915A - Electronic cam control method - Google Patents

Abstract

The invention discloses an electronic cam control method. An electronic cam comprises a processor used as a control module, a single chip microcomputer used as a communication module and an execution unit. The processor used as the control module receives a sensor signal and outputs a control signal to an I/O circuit through operation in combination with set parameters. The single chip microcomputer used as the communication module communicates with a touch screen through an RS 232 port and receives a control command and relative data from the touch screen. The control module communicates with the communication module through TTL level signals. The execution unit comprises a servo drive and a servo motor. The processor used as the control module carries out motion track control on speed and acceleration of an electronic cam through a cubic function and a quadratic function respectively. According to the electronic cam control method, processing precision is high, motions are flexible and smooth, production efficiency can be greatly improved, and the electronic cam control method is suitable for the industrial field of packing, textile, printing and the like.

Description

A kind of control method of electric cam

Technical field

The invention belongs to the industrial automatic control field, specifically, relate to a kind of control method of electric cam.

Background technology

Electric cam is to grow up on the basis of mechanical cam, its key concept is a set of digital control system in the situation that there is no traditional mechanical cam, by the establishment control program, allow the simulation cam work curve of this digital control system precision, and complete corresponding mechanical action, having been completed the characteristics of motion of cam mechanism by a set of digital control system, is typical electro-mechanical system.With mechanical cam, compare, electric cam almost can be realized cam curve arbitrarily and not be subject to the constraint of physical construction.Electric cam has very significantly advantage at aspects such as precision, flexibility, production efficiency, speed and acceleration limit simultaneously.

Chinese patent application CN102650862A discloses a kind of electronic cam control system and method for programmable logic controller (PLC), its main spindle's data that obtain Nodes by the FPGA module and the difference of main shaft current location and from the shaft position data and exported the poor of umber of pulse from axle, and control accordingly from axle and move, not only save the resource of programmable logic controller (PLC), and greatly improved the control accuracy of electric cam.The technical matters of its required solution is, programmable logic controller (PLC) takies more cpu resource at the main shaft of realizing electric cam with when the axle engagement action concerns, and affects the problem of the control accuracy of scan period of programmable logic controller (PLC) and electric cam.

Chinese patent application CN200820179638.6 discloses a kind of Programmable Logic Controller that includes electronic cam control system, its fiduciary level for Programmable Logic Controller and controller system due to electric cam module or electronic cam controller separate setting and the poor technical matters of ease of use, by control able to programme unit and electric cam control module system are arranged in the control core chip simultaneously, make control able to programme unit and electric cam control module can share the relevant control unit, reduce complex circuit produced phase mutual interference is set, save space thereby reach, simplify the technique effect of controlling and improve system reliability.

Technique scheme does not all relate to the flatness that how to improve the electric cam movement locus, the technical matters of the aspects such as dirigibility that particularly how to guarantee the continuity of electric cam speed-change process and control, there be many needing to be further improved and improvements in these areas in prior art.

Summary of the invention

Task of the present invention is to provide a kind of electric cam, it mainly sets up the motion control function of electric cam according to the characteristics of motion of mechanical cam, by the establishment control program, utilize the Single-chip Controlling servomotor, improve the dirigibility of camming movement control and the flatness of movement locus.

The present invention is that the technical scheme that solves the problems of the technologies described above employing is, a kind of control method of electric cam comprises the processor that is used as control module, single-chip microcomputer, the touch-screen that is used as communication module, and performance element; The above-mentioned processor sensor-lodging as control module, the parameter in conjunction with setting, output a control signal to the I/O circuit by computing;

Above-mentioned its peripheral circuit of single-chip microcomputer as communication module mainly consists of RS232 serial communication circuit, level shifting circuit;

The above-mentioned single-chip microcomputer as communication module, by RS232 interface and touch panel communication, receives steering order and related data from touch-screen;

Above-mentioned processor as control module and as between the single-chip microcomputer of communication module by the communication of Transistor-Transistor Logic level signal;

Above-mentioned performance element comprises that servo-driver reaches the servomotor by its driving, and this performance element is responsible for receiving the order as the processor of control module, and carries out by servomotor.

The above-mentioned processor as control module uses respectively cubic function and quadratic function to carry out movement locus control to the velocity and acceleration of electric cam.

Technique scheme, mainly utilize the fast response characteristic of the high-speed computation performance of ARM7 and servo-drive system to realize the characteristics of motion of mechanical cam, wherein between control module and communication module, by the Transistor-Transistor Logic level signal, get in touch with, control module reads the relevant control parameter from communication module, generate cam curve and carry out the discretize processing, generate simultaneously and control form storage, then control performance element and complete corresponding action; Control module, according to the information of sensor feedback, judges the position at each motor shaft place, thereby has realized closed-loop control.

And operating personnel intuitively carry out modification and the adjustment of parameter by touch-screen, this makes operation easier, has reduced operating personnel's labour intensity.

As preferably, it is core that the above-mentioned processor as control module be take main flow flush bonding processor microprocessor, comprise FLASH storer, SDRAM storer and the reset circuit be comprised of reset chip, its peripheral function circuit includes sensor signal processing circuit, motor-drive circuit; Wherein:

Communication module be take the 89C52 single-chip microcomputer as core, comprises that serial communication circuit and 5V turn the 3.3V circuit;

Performance element comprises that three servo-drivers reach three servomotors by its driving.

Explain and explanation: above-mentioned main flow flush bonding processor can be selected the ARM7 chip, and microprocessor can be selected S3C44B0X, and the SDRAM storer can be selected HY57V641620, and the FLASH storer can be selected SST39VF1601.

The direct technology effect that this optimal technical scheme produces is to have improved the dirigibility of electric cam motion control and the flatness of movement locus.

As preferably, the above-mentioned single-chip microcomputer as communication module is built based on the 80C51 single-chip microcomputer.

The beneficial effect of this optimal technical scheme is that simple in structure, maintenance and repair is easy.

As preferably, between the above-mentioned single-chip microcomputer as communication module and touch-screen, based on the Modbus rtu protocol, communicate.

The beneficial effect of this optimal technical scheme is, operating personnel carry out modification and the adjustment of parameter by touch-screen, and its course of reaction is more smooth, sensitiveer.

To sum up, the present invention is by adopting the beneficial effect that technique scheme is brought to be, the speed-change process transitions smooth of electric cam, its speed-change process continuously, without sudden change, that can use according to reality need to be regulated the electric cam movement locus at any time, controls flexibly.

And operating personnel intuitively carry out modification and the adjustment of parameter by touch-screen, this makes operation easier, has reduced operating personnel's labour intensity.

The accompanying drawing explanation

Fig. 1 is electric cam physical model structure schematic diagram of the present invention;

Speed and acceleration plots that Fig. 2 is electric cam motion of the present invention;

Fig. 3 is electronic cam controller structural representation of the present invention.

Description of reference numerals: 1, ARM7 chip S3C44B0X, 2,89C52 single-chip microcomputer, 3, SDRAM HY57V641620,4, reset chip, 5, FLASH SST39VF1601,6, sensor signal processing circuit, 7, sensor, 8, motor-drive circuit, 9, servomotor, 10, touch-screen, 11, serial communication circuit, 12, level shifting circuit.

Embodiment

Below in conjunction with accompanying drawing, the present invention is described in detail.

As shown in Figure 1, the electric cam physical model, the profile of its cam is comprised of AB, BC, CD and tetra-sections curves of DA, and cam rotates with constant angular velocity ω, and the speed of DA section is v ₁, the speed of BC section is v ₂, in the process that cam runs to B by A, its speed is by v ₁accelerate to v ₂, in the process that cam runs to D by C, its speed is by v ₂decelerate to v ₁.According to the speed characteristics of above-mentioned each section, can low regime (DA section), accelerating region (AB section), high velocity (BC section) and deceleration area (CD section) will be divided between the motor area of electric cam.For easier realize that camming movement guarantees the flatness of its motion simultaneously, adopt the cubic function control rate at accelerating region and deceleration area the present invention, adopt quadratic function to control acceleration.

For understanding better technical scheme of the present invention, existing as follows in conjunction with the ultimate principle labor:

As shown in Figure 2, the speed of camming movement and accelerating curve.The rate equation of accelerating region can be made as:

v(t)=a ₀+a ₁t+a ₂t ²+a ₃t ³ (1)

The acceleration equation that differentiate can obtain accelerating region is:

v′(t)=a ₁+2a ₂t+3a ₃t ² (2)

As shown in Figure 3 as downstream condition: (t ₁, v ₁), (t ₂, v ₂) and (t ₁, 0), (t ₂, 0), substitution formula (1) and formula (2) obtain respectively:

$\left\{\begin{array}{c}{a}_0+a_1{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+a_2{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_1^2+a_3{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_1^3=v_1\\ a_0+a_1{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA00003658080700011.png,HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+a_2{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA00003658080700011.png,HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_2^2+a_3{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA00003658080700011.png,HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_2^3=v_2\\ a_1+2a_2{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+3a_3{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_1^2=0\\ a_1+2a_2{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA00003658080700011.png,HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_2+3a_3{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA00003658080700011.png,HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_2^2=0\end{array}\right.---\left(3\right)$

The rate equation that solving equations (3) can obtain accelerating region is:

$v\left(t\right)=\frac{2(v_2-v_1)}{{(t_1-t_2)}^3}{t}^3-3(v_2-v_1)\frac{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+t_2}{{(t_1-t_2)}^3}{\mathrm{<figure-callout\; id="2"\; label="t"\; filenames="HDA00003658080700011.png,HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}^2+6(v_2-v_1)\frac{t_1{t}_2}{{(t_1-t_2)}^3}t+(v_2-v_1)\frac{{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_1^3-3{\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_1^2{t}_2}{{(t_1-t_2)}^3}+v_1---\left(4\right)$

The acceleration equation is:

$v^{\text{'}}\left(t\right)=\frac{6(v_2-v_1)}{{(t_1-t_2)}^3}\{t^2-({\mathrm{<figure-callout\; id="1"\; label="t"\; filenames="HDA00003658080700031.png"\; state="\{\{state\}\}">t</figure-callout>}}_1+t_2)t+t_1{t}_2\}---\left(5\right)$

As shown in Figure 3, the electronic cam controller structured flowchart mainly comprises control module, communication module and performance element.

Wherein, control module be take ARM7 chip S3C44B0X(1) be core, comprise SDRAM HY57V641620(3), FLASH SST39VF1601(5) and the reset circuit that formed by reset chip (4), its peripheral function circuit comprises sensor signal processing circuit (6), motor-drive circuit (8) etc.;

It is core that communication module be take 89C52 single-chip microcomputer (2), comprises that serial communication circuit (11) and 5V turn 3.3V circuit (12).Realized communicating by letter of 89C52 single-chip microcomputer (2) and touch-screen (10) based on the Modbus rtu protocol;

Performance element comprises three servomotors that are set up in parallel (9).

The now control method of 3 pairs of electric cams of the present invention and workflow by reference to the accompanying drawings are described in detail as follows:

As shown in Figure 3,89C52 single-chip microcomputer (2) receives the information frame sent from touch-screen (10) by RS232 serial communication circuit (11), and extracts function code and data bit wherein, and assignment is to P1 mouth and P0 mouth respectively;

The level shifting circuit (12) formed by transistor output photoelectric coupling mechanism TLP521 optocoupler converts the level signal of 5V to 3.3V, and the form that numerical value of above-mentioned I/O mouth can Transistor-Transistor Logic level sends ARM7 chip S3C44B0X(1 to) the C mouth;

After the level of C mouth (totally 16) changes, read respectively its most-significant byte and least-significant byte, to obtain function code and data value.Chip S3C44B0X(1) automatically generate corresponding cam curve and its discretize processed to produce to control simultaneously and use array, i.e. pulsed frequency array and pulse number array according to above-mentioned functions code and data value;

Pulse producer PWM0,1,3 produces the square-wave signals of characteristic frequency and some according to above-mentioned array, can control any one in three servomotors that are set up in parallel (9) by motor-drive circuit (8) and realize that camming movement or three-shaft linkage realize specific function.

Sensor (7) quantity that is arranged on each axle is provided with a plurality of according to actual needs, such as the sensor that can be used for scrambler, photoelectricity switch, color mark sensor, limit switch etc., the signal of its output is after sensor signal processing circuit (6) modulation, the external interrupt function mouth EINT0-7 of input S3C44B0X chip (1), form closed-loop control accurately to control the position of each axle.

The sensor signal processing circuit (6) mainly comprises the photoelectric isolating circuit be comprised of transistor output photoelectric coupling mechanism TLP521 optocoupler and the encoder signal processing circuit be comprised of receiver AM26LS32 chip and level switch module SN74LVC4245A chip.

Claims (4)

1. the control method of an electric cam, comprise the processor that is used as control module, single-chip microcomputer, the touch-screen that is used as communication module, and performance element; It is characterized in that, the described processor sensor-lodging as control module, the parameter in conjunction with setting, output a control signal to the I/O circuit by computing;

Described its peripheral circuit of single-chip microcomputer as communication module mainly consists of RS232 serial communication circuit, level shifting circuit;

The described single-chip microcomputer as communication module, by RS232 interface and described touch panel communication, receives steering order and related data from touch-screen;

The described processor as control module and described as communicating by letter by the Transistor-Transistor Logic level signal between the single-chip microcomputer of communication module;

Described performance element comprises that servo-driver reaches the servomotor by its driving; Described performance element is responsible for receiving the order of the described processor as control module, and carries out by described servomotor.

The described processor as control module uses respectively cubic function and quadratic function to carry out movement locus control to the velocity and acceleration of described electric cam.

2. the control method of electric cam according to claim 1, it is characterized in that, it is core that the described processor as control module be take main flow flush bonding processor microprocessor, comprise FLASH storer, SDRAM storer and the reset circuit be comprised of reset chip, its peripheral function circuit includes sensor signal processing circuit, motor-drive circuit;

Described communication module be take the 89C52 single-chip microcomputer as core, comprises that serial communication circuit and 5V turn the 3.3V circuit;

Described performance element comprises that three servo-drivers reach three servomotors by its driving.

3. the control method of electric cam according to claim 2, is characterized in that, the described single-chip microcomputer as communication module is built based on the 80C51 single-chip microcomputer.

4. according to the control method of the arbitrary described electric cam of claim 1-3, it is characterized in that, communicate based on the Modbus rtu protocol between the described single-chip microcomputer as communication module and described touch-screen.

Images