CN1060711C - Intelligent feed control system for grinding machines - Google Patents

Abstract

The invention discloses a grinding machine intelligent feed control method and device. Before grinding workpieces, the feed amount of the grinding head is first set with a dialer, the grinding head is fed, and the detection circuit measures the empty space of the grinding head motor. The current I and the voltage U are rectified and filtered to obtain the power control pulse width. After several cycles, the set power is obtained; when the grinding head and the grinding wheel are approaching the workpiece, the grinding head is controlled by the output amplification link to start grinding. The invention has the advantages of strong anti-interference ability, high processing precision, can improve work efficiency and automation, and greatly reduce labor intensity. It can work on the knife and eliminate the interference of various external factors. It is suitable for grinding machines with various AC and DC power supplies.

Description

Grinding machine intelligent feed control method and device

The invention relates to an intelligent control method and device for grinding head feeding of a grinding machine.

The grinding machine is a high-precision processing equipment for grinding workpieces with grinding heads. When grinding workpieces, the grinding head needs to be aligned with the workpiece first. The traditional way of tool setting is: turn the hand wheel manually, feed in a small amount, and observe whether there is spark at the grinding head. Due to the small machining allowance, excessive feeding will cause waste products, and the purpose of tool setting cannot be achieved without touching the workpiece. , this method is time-consuming and labor-intensive, with low efficiency, and cannot guarantee the accuracy of tool setting.

Soviet Patent No. SU798714 discloses a device for controlling the feed of a grinding machine by comparing the power measured by a threshold comparator through a differentiator and two integrators. It uses analog circuits (differentiation, integration, comparison, etc.) to sample And control, so its tool setting accuracy is easily affected by power fluctuations and component accuracy, especially the artificially set comparator threshold, the preset value is more sensitive to external influences, and directly disturbs the control and detection accuracy. The sampling detection circuit of the device adopts The detection range of the differential and integral circuit depends on the value of resistance and capacitance. For different powers and grinding heads with different external conditions, different values should be taken correspondingly, which makes adjustment difficult, and repeated debugging is required to obtain the best fit. However, Even if it is adjusted well under certain conditions, it is difficult to adapt to the grinding head with variable no-load power. The no-load power of the actual working grinding head is affected by many external factors, such as the balance of the grinding wheel, the change of the size of the grinding wheel, the change of the coolant, and the grinding head. The difference between the cold state and the hot state of the main shaft, the length of the belt that drags the grinding head motor, and the fluctuation of the power supply will cause the same grinding head motor to work at different times, and the fluctuation of the no-load power under different conditions will be different, and the fluctuation amount will often increase. The power increment that exceeds the required detection of the tool setting growth will cause firstly a false action during tool setting (that is, it will act without touching the workpiece), and secondly, the tool setting depth will be inconsistent or too large.

European patent 0496303Al discloses a kind of cylindrical grinder of grinding growth type crystal, and it is to adopt no-load as the first kind of speed change feed speed, switch to the second kind of speed (low speed) after reaching the setting value, when turning from high speed When the feed rate is low, the cutting amount of the workpiece to be processed will be large, which is equivalent to rough machining again, and then finish machining at low speed. Because the switching point is affected by the fluctuation of the no-load current, the shape and size of the workpiece to be processed fluctuate accordingly, and it has to be adjusted artificially frequently.

The purpose of the present invention is to provide a grinding machine intelligent feed control system that adopts digital circuit shaping and single-chip digital processing to obtain dynamic no-load active power values, so as to effectively suppress external disturbances and improve sensitivity, thereby improving processing accuracy and saving tool setting time, reduce labor intensity and improve work efficiency.

The present invention is realized in this way: before grinding the workpiece, first set the feeding amount of the grinding head with the dialer, and this amount is reflected as the power increment ΔP of the grinding head motor; then connect the working power supply, and store ΔP into the The internal memory, the grinding head feed, and the detection circuit measure the no-load current I and voltage U of the grinding head motor and rectify and filter, then amplify through the amplifier, shape the shaping circuit, and then pass through the phase detector to obtain the power control pulse width. In the second cycle, several groups of no-load power average values P1, P2, P3... are taken, and then the maximum value Pmax is taken out as the reference value and stored in the single-chip microcomputer, and Pmax and ΔP are superimposed to obtain the set power P'; In the process of the grinding wheel approaching the workpiece, the power P is continuously detected, and P is compared with P'. If P≥P' and lasts for several cycles, the single-chip microcomputer outputs a control signal, controls the grinding head through the output amplification link, and starts grinding. The above process All are executed under the control of the execution software.

Described execution software process is: 1., initialization-2. sampling-3., to P pulse width counting-4., whether P ' is obtained, as obtaining turn 8. execute-5., calculate group mean value P, when group sampling value number is insufficient Return to ②-⑥, find the maximum value Pmax in the average value of each group, if the number of groups is insufficient, return to ②-⑦, Pmax and ΔP are superimposed to get P', store-⑧, set the flag of P<P' to 1 and return to ②-⑨, Judging whether the number of times P≥P' is equal to the set number No, if it is less than No, return to ②-⑩, output stop feed signal-end.

The grinding machine intelligent feed control device is composed of a working power supply 1, a detection circuit 2, an amplifier 3, a shaping circuit 4, a phase detector 5, a single-chip microcomputer 6, an output amplification link 7 and functional software. The phase detector is composed of a trigger and an exclusive OR gate. , the connection method is: the CP terminal of the trigger is connected to the input signal I, the D terminal is connected to the Q terminal of the flip-flop, and the Q terminal is connected to the XOR gate-input terminal; the CP terminal of the flip-flop is connected to the input signal U The D terminal is connected with the Q terminal of the flip-flop, the Q terminal is connected with the XOR gate-input terminal, and the output of the XOR gate is connected to the single-chip microcomputer.

Compared with the prior art, the present invention has strong anti-interference ability, high processing precision, can improve work efficiency and degree of automation, greatly reduce labor intensity, has the advantages of simple hardware structure, small volume, low price, ^{etc. 6} m level, the operator does not need to manually adjust the grinding head repeatedly, just set the feed amount before starting the machine, and the grinding head can complete the automatic tool setting within one minute after starting the machine, and can eliminate various external factors Interference, suitable for grinding machines with various AC and DC power supplies.

Accompanying drawing 1 is a system structural block diagram of the present invention;

Accompanying drawing 2 is the waveform diagram of phase detector circuit principle of the present invention;

Accompanying drawing 3 is phase detector input and output waveform figure of the present invention;

Accompanying drawing 4 is a working principle block diagram of the present invention;

Accompanying drawing 5 is the program block diagram of embodiment 1 of the present invention;

Accompanying drawing 6 is the program block diagram of embodiment 2 of the present invention.

Implementation of the present invention will be further described below in conjunction with accompanying drawing:

Embodiment 1: When the grinding head motor is an AC motor, firstly connect the jumper pieces F1, F2, F3, disconnect the jumper piece and open F4, F5 after starting the machine, the current signal I is filtered by full-wave rectification, and the signal is made by the amplifier LM324 After amplification, one way is used as an overload protection signal and sent to the output amplification link; one way is shaped by the flip-flop 74LS14 to obtain an I pulse signal, and this signal is used as the I signal input of the single-chip microcomputer 8031, and the other is used as a phase detector input, and the voltage signal U is passed through the full wave After rectification and filtering, the U pulse signal is obtained through the shaping of the flip-flop 74LS14. One way of this signal is used as the U signal input of the single-chip microcomputer 8031, and the other is used as the input of the phase detector. The two flip-flops of the phase detector 74LS74 pair the input I, U After the pulse signal is further shaped, the U' and I' waveforms shown in Figure 3 are obtained, and then the XOR gate 74LS86 is used to perform XOR to obtain the pulse width of P (power). (500KHZ) first fill the P pulse width (low level) with high frequency, and use the voltage wave as a reference to determine the starting point for counting the P pulse width. frequency interference, the power supply is purified and rectified and stabilized to provide the +5V, +15V and -15V power supplies of the system, the read-only memory 2716 stores the execution software, and the output operation of the amplifying output link execution device is provided. Accompanying drawing 5 is the present embodiment Execute the software block diagram. Before starting up, first use the 8421 dial to set the feed rate of the grinding head. This amount is reflected as the incremental ΔP of the motor power of the grinding head. internal memory; clear the output port, set the input port to 1, clear the flag bit, set the status bit C/T=O (internal pulse count), set No=10, N2=30, (2) judge ( Whether the grinding head motor is energized, if there is no current or voltage signal, execute (3)) (3) output an alarm signal, (4) set the number of samples N1=15, (5) judge (U=0 and P=0 is not established Then return to execute (5)), (6) Judgment (U=1 and P=1 is not established, return to execute (6)), (7) Judgment (U=1 and P=0 is not established, return to execute (7)), ( 8) The counter fills and counts the P pulse width (low level part), (9) judges whether the counting is complete (U=0 and P=0 is not established, return to execute (8)), (10) stop counting, save the result, (11) Judgment (U=0 and P=0 is not established, return to execute (11)), (12) Open the channel, accumulate, (13) Judgment (U=1 and P=1 is not established, return to execute (12)), (14) Correct the count value (P=P-2ΔU), (15) Determine whether the dynamic initial value is positive or negative (P' is not zero, execute (21)), (16) Save the P value, and save the number of groups minus 1 , (17) Judgment (group number unit value = 0 is not established, return to (5)), (18) calculate the average value, and save, the number of groups is reduced by 1 to save, (19) Judgment (group number unit value = 0 is not established, return (4)), (20) Find the maximum value Pmax in the average value of each group, calculate P'=Pmax+ΔP, and then return to (5), (21) judgment (P≥P' is not established and execute (22)), ( 22) After the flag 1 is set to 1, return to execute (5), (23) judgment (flag 1=1, then execute (24)), (24) flag 1=0, counter II=No (secondary counter reassignment) and then Return to execute (5), (25) counter Ⅱ = counter Ⅱ-1, judge (counter Ⅱ = 0 is not established, return to (5), (26) P1, port 3 = 1, output control signal to control the grinding head feed motor to stop Feed, (27) ends.

Embodiment 2: When the grinding head motor is a DC motor, at first disconnect the jumper F1, F2, F3, connect the jumper F4, F5, because the power P of the DC motor is proportional to the current I, the voltage can be regarded as a constant, Therefore, the change of ΔP can be measured only by detecting the change of ΔI. After starting up, the current signal I measured by the Hall element is sampled and filtered, and after the signal is amplified by the amplifier LM324, the overload protection signal is sent to the output amplification link all the way. , all the way through the voltage/frequency conversion to get the I pulse signal (its frequency is proportional to the amplitude of I), this signal is input as the I signal of the single-chip microcomputer 8031, and the single-chip microcomputer 8031 can obtain the corresponding I pulse signal by timing sampling of the I pulse signal. Different digital quantities, the circuit function of other parts is the same as that of embodiment 1. Accompanying drawing 6 is a block diagram of the execution software of this embodiment. Before starting the machine, first set the feeding amount of the grinding head with the 8021 dialer, and the amount is reflected as grinding head The increment ΔI of the motor current, after starting up, (1) Initialization part: store ΔI in the internal memory of the single-chip microcomputer 8031, clear the output port, set the input port to 1, clear the flag bit, and set the status bit C/T =1 (external pulse count), set No=10, N2=30, (2) set the group sampling number N1=15, (3) enable interrupt, (4) wait (10ms), when the interrupt signal arrives, transfer to the interrupt service program Entrance, (5) get I count value, save, (6) return, (7) get I value, (8) judge (I' is not zero turn (16)), (9) judge (whether the grinding head motor is energized , execute (10) if I=0), (10) output alarm signal, (11) accumulate, the number of groups minus 1 is saved, (12) judge (group number unit value=0 is not established, return (3)), ( 13) Find the average value of the group, and save it, and save it by subtracting 1 from the number of groups, (14) judge (the group number unit=0 is not established and return to (2)), (15) find the maximum value Imax in the average value of each group, and calculate I' =Imax+ΔI, then return to (3), (16) judge (I≥I' is not established and execute (17)), (17) return to execute (3) after flag 1 is set to 1, (18) judge (flag 1=1 , then execute (19)), (19) flag 1=0, counter II=No (secondary counter reassignment) and then return to execute (3), (20) counter II=counter II-1, judge (counter II= If 0 is not established, return to (3)); (21) P1.3 port = 1, the output control signal controls the grinding head feed motor to stop feeding. (22) END.

Claims (3)

1, a kind of grinding machine intelligence feed control method, it is characterized in that: before grinding work piece, at first set the grinding wheel feed amount with DIP device, this quantitative response is grinding head motor power increment Δ P; Connect working power (1) then, Δ P is deposited in the internal storage of single-chip microcomputer (6), grinding wheel feed, testing circuit (2) records no-load current I and the voltage U and the rectifying and wave-filtering of grinding head motor, amplify through amplifier (3) then, shaping circuit (4) shaping, again by phase discriminator (5), obtain power control pulsewidth, through repeatedly circulation, get some groups of no-load power average value P 1, P2, P3 ..., take out wherein maximum Pmax then and be decided to be a reference value and deposit single-chip microcomputer (6) in, with Pmax and Δ P stack, draw setting power P '; In the process of grinding head grinding wheel convergence workpiece, constantly detection power P compares P and P ', if P 〉=P ', and continue some circulations, single-chip microcomputer (6) output control signal, by output amplifying element (7) control bistrique, the beginning grinding, said process is carried out by executive software control.

2, grinding machine intelligence feed control method according to claim 1, it is characterized in that: described executive software flow process is: 1., initialization-2. sampling-3., to P pulsewidth counting-4., whether P ' obtains, as obtain commentaries on classics and 8. carry out-5., calculate cell mean P, return 2. when group sampled value number is not enough-6., ask maximum Pmax in each cell mean, return 2. when the group number is not enough-7., Pmax and Δ P superpose P ', storage-8., judge P＜P ' sign put 1 return 2.-9., judge whether P 〉=P ' number of times equals to be provided with several No, as return 2. less than No-10., output feed-disabling signal-end.

3, a kind of grinding machine intelligence feed control device, form by working power (1), testing circuit (2), amplifier (3), shaping circuit (4), phase discriminator (5), single-chip microcomputer (6), output amplifying element (7) and functional software, it is characterized in that: phase discriminator (5) is made up of trigger (8), (9) and XOR gate (10), its connected mode is: the CP end of trigger (8) is connected with input signal I, the D end is connected with the Q end of trigger (9), and Q holds with XOR gate (10)--input is connected; The CP end of trigger (9) is connected with input signal U, and the D end is connected with the Q end of trigger (8), and the Q end is connected with XOR gate (10)-input, and the output of XOR gate (10) is connected to single-chip microcomputer (6).

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