CN101875173A - Gantry type milling and boring machine adopting electromagnet and permanent magnet mixed magnetic pole suspending and control method thereof - Google Patents

Abstract

The invention provides a gantry type milling and boring machine adopting electromagnet and permanent magnet mixed magnetic pole suspending and a control method. The gantry type milling and boring machine comprises a machine body and a gantry beam, wherein a linear propulsion system is arranged between the machine body and the gantry beam; and the gantry beam is also provided with an electromagnet and permanent magnet mixed magnetic pole suspending electromagnet capable of suspending the gantry beam above the machine body, and the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet is arranged at one side of the gantry beam, facing towards the bottom edge of the machine body, and is connected with a control system. In the control method, an eddy current type displacement sensor is used for sampling the suspending situation of the gantry beam, a DSP (Digital Signal Processor) controller is used for carrying out comparison calculation on current information and preset information, and then a D/A (Digital/Analog) converter and a power amplifier are used for accurately adjusting the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet arranged on the gantry beam so as to complete the control of the suspending situation of the gantry beam. The invention is concise and reasonable, has strong practicability, and is relatively suitable for being used in the technical field of numerical control machining.

Description

The plane milling and boring machine of electromagnet and permanent magnet mixed magnetic pole suspending and control method thereof

Technical field: the invention provides a kind of plane milling and boring machine that adopts electromagnet and permanent magnet mixed magnetic pole suspending, the invention belongs to the Computerized Numerical Control processing technology field, the control method of particularly a kind of boring and milling machine gantry levitation device and the real-time controller parameters setting of genetic algorithm thereof.

Background technology: along with the continuous development of scientific and technological industry, the requirement to high manufacturing accuracy and efficient in the industrial manufacture process improves constantly, and therefore contactless magnetic suspension system is widely used in the various manufacturing equipments further.The movable gantry digital-control boring-milling machine is important and one of the most representative large-sized processing equipment, in the movable gantry digital-control boring-milling machine, exists friction between gantry crossbeam that moves and the bed ways, this friction have hundred evils and none profit.And want fundamentally thoroughly to solve friction problem, and have only the contact-making surface of two relative motions is separated, directly do not come in contact.That is to say, the movable body with constant weight is suspended that this is only the basic outlet that solves friction problem.Adopt the electromagnetic suspension technology gantry of moving to be suspended for this reason, drive the gantry frame motion, can realize not having the friction operation by linear electric motors by magnetic field force.

Compare with traditional travelling gantry, magnetic suspension gantry has and does not have machinery friction, contactless wearing and tearing and non-lubricating advantage.Because not contact between relative motion surface, thereby thoroughly eliminated creeping phenomenon, not because of the precise decreasing and the life problems of wearing and tearing and contact fatigue is produced, and the controllability of electronic component is better than machine components, makes its controllability be higher than traditional travelling gantry; And saved the essential huge oil circuit auxiliary equipment of hydrostatic slideway, and environment is not produced pollution, reduced the dustproof condition of super cleaning; Because ACTIVE CONTROL has been adopted at electromagnetic levitation type gantry, can improve the information processing capability of Digit Control Machine Tool, as operating mode detection, forecast and fault diagnosis.And there are advantages such as operating temperature range is big, maintenance is simple, the life-span is long at electromagnetic levitation type gantry.But on the crossbeam that magnetic levitation technology will be applied to the portable lathe of large-sized gantry suspends, also have many key technologies etc. to be solved, here, because big by the quality of the crossbeam that suspended, add man-hour to the serious interference of hoverheight, require the very high and system of the dynamic and static precision of hoverheight to have high rigidity, can the Ultra-Low Speed feeding etc., in this and other field the desired performance of suspension system is had significant difference.These particularity require to have proposed very harsh requirement to the research work of this suspension system, and control technology has been proposed stern challenge.Compare with magnetic suspension train, magnetic suspension train does not have too high requirement for the accuracy of hoverheight, because needs are manned, requires comfortable, safe and stable getting final product.The Digit Control Machine Tool moving-member of magnetic suspension control also requires high accuracy supporting and location except requiring high-speed driving, particularly fine finishining under the little feeding state of low speed just has very high requirement to magnetic suspension accuracy, rigidity and robustness highly.

Summary of the invention:

Goal of the invention: the invention provides a kind of plane milling and boring machine and control method thereof that adopts electromagnet and permanent magnet mixed magnetic pole suspending, to such an extent as to its objective is solution in the past gantry crossbeam that moves and bed ways between exist friction influence the problem of operating efficiency.

Technical scheme: the present invention is achieved through the following technical solutions:

A kind of plane milling and boring machine that adopts electromagnet and permanent magnet mixed magnetic pole suspending, mainly comprise lathe bed and gantry crossbeam that can relatively move with lathe bed, be provided with the linear advancement system that driving gantry crossbeam and lathe bed relatively move between described lathe bed and gantry crossbeam, it is characterized in that: on the crossbeam of described gantry, also be provided with the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet that gantry crossbeam is suspended on lathe bed, the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet is arranged on the crossbeam of gantry a side on edge at the bottom of lathe bed, the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet is connected with control system, and described electromagnet and permanent magnet mixed magnetic pole suspending electromagnet is the magnet that is tied with hot-wire coil that has permanent magnetism magnetic pole; Described permanent magnetism magnetic pole is arranged on the position near edge at the bottom of the lathe bed.

Described linear advancement system is a permanent magnet linear synchronous motor, and the mover of this permanent magnet linear synchronous motor is arranged on the crossbeam of gantry, and its stator is fixed on the lathe bed; Also be provided with guiding electromagnet between described gantry crossbeam and lathe bed, described guiding electromagnet is arranged on the crossbeam of gantry on the position of lathe bed both sides.

Described control system comprises JTAG emulator, dsp controller, D/A converter, A/D converter, power amplifier and electric vortex type displacement sensor; Described JTAG emulator is connected to dsp controller, and dsp controller is connected to D/A converter, and D/A converter is connected to power amplifier, and power amplifier is connected to the hot-wire coil of electromagnet and permanent magnet mixed magnetic pole suspending electromagnet and the hot-wire coil of guiding electromagnet; Be provided with the electric vortex type displacement sensor between described electromagnet and permanent magnet mixed magnetic pole suspending electromagnet and the lathe bed, also be provided with the electric vortex type displacement sensor between described guiding electromagnet and the lathe bed, the electric vortex type displacement sensor is connected to dsp controller by A/D converter.

A kind of control method of controlling the plane milling and boring machine of above-mentioned employing electromagnet and permanent magnet mixed magnetic pole suspending, it is characterized in that: this method is earlier with a pair of permanent magnet, utilize coil windings to twine and form the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet that control gantry crossbeam suspends, by the electric vortex type displacement sensor in the control system suspension situation of gantry crossbeam is sampled then, then information is transmitted in the dsp controller by A/D converter, after by dsp controller this information and predefined information being compared calculating, by D/A converter and power amplifier the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet on the crossbeam of gantry is adjusted accurately again, finished control gantry crossbeam suspension situation.

The concrete steps of described control method are as follows:

Step 1, dsp controller carry out system initialization;

Whether step 2, the plane milling and boring machine that detects this employing electromagnet and permanent magnet mixed magnetic pole suspending have the ending request signal; If there is the ending request signal to forward step 13 to; If do not have the ending request signal then continue;

Whether the plane milling and boring machine of step 3, the whole employing electromagnet and permanent magnet mixed magnetic pole suspending of detection has interrupt request singal;

If step 4 there is not interrupt request singal, then wait for and interrupting, go back to step 3;

If step 5 interrupt to arrive, reading, and start analog-digital converter, the information of the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) that the electric vortex type displacement sensor is gathered is transmitted in the dsp controller by analog-digital converter;

Step 6, in dsp controller, carry out calculating based on the adjust control algolithm of pid parameter of genetic algorithm;

Step 7, whether testing result has overflows;

Overflow if step 8 has, get extreme value, return step 7;

If step 9 is not overflowed, testing result whether be on the occasion of;

If whether step 10 result is negative value, negate;

If step 11 result whether be on the occasion of, the result is carried out exporting after the digital-to-analogue conversion and by power amplifier;

Step 12, interruption are returned, and go back to step 2.

Step 13, end.

In described " step 6 " be based on the adjust concrete steps of control algolithm of pid parameter of genetic algorithm:

Step 1, defined variable, initiation parameter.

Step 2, produce n the individual initial population P (0) of formation at random;

Step 3, calculating target function value.With each individual decoding corresponding parameters value in the population, ask target function value J with this parameter.

Step 4, calculating fitness function value f get

And ordering;

Step 5, determine that formula sampling selects.

Step 6, the single-point intersection of carrying out.

Step 7, evenly variation.Produce population of future generation.

Whether do step 8, detection genetic algebra satisfy setting value? if do not satisfy, rotate back into step 3.

Step 9, end.

The online real-time Tuning PID Controller device parameter of described employing genetic algorithm, select optimum index to be:

$J={\&Integral;}_0^{\&infin;}\left({\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400022.png,DEST\_PATH\_HSB00000224334400031.png"\; state="\{\{state\}\}">w</figure-callout>}}_1\right|e\left(t\right)|+w_2{u}^2\left(t\right))\mathrm{dt}+{\mathrm{<figure-callout\; id="3"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400011.png,DEST\_PATH\_HSB00000224334400022.png"\; state="\{\{state\}\}">w</figure-callout>}}_3\&CenterDot;t_u$

In the formula, e (t) is a systematic error, and u (t) is controller output, t _uBe the rise time, w ₁, w ₂, w ₃Be weights.For fear of overshoot, adopted punitive function, promptly in case produce overshoot, with overshoot as optimum index, this moment, optimum index was:

$\mathrm{if\; ey}\left(t\right)<0J={\&Integral;}_0^{\&infin;}\left({\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400022.png,DEST\_PATH\_HSB00000224334400031.png"\; state="\{\{state\}\}">w</figure-callout>}}_1\right|e\left(t\right)|+w_2{u}^2\left(t\right)+{\mathrm{<figure-callout\; id="4"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400011.png,DEST\_PATH\_HSB00000224334400022.png"\; state="\{\{state\}\}">w</figure-callout>}}_4|\mathrm{ey}\left(t\right)\left|\right)\mathrm{dt}+{\mathrm{<figure-callout\; id="3"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400011.png,DEST\_PATH\_HSB00000224334400022.png"\; state="\{\{state\}\}">w</figure-callout>}}_3\&CenterDot;t_u$

In the formula, w ₃Be weights, and w ₄＞＞w ₁, ey (t)=y (t)-y (t-1), y (t) is controlled device output.

And during the online real-time Tuning PID Controller device parameter of genetic algorithm, adopt and determine that the formula sampling selects and the single-point interleaved mode.

Advantage and effect: the invention provides the plane milling and boring machine of a kind of employing electromagnet and permanent magnet mixed magnetic pole suspending, mainly comprise lathe bed and gantry crossbeam that can relatively move with lathe bed, be provided with the linear advancement system between described lathe bed and gantry crossbeam; Also be provided with the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet between described gantry crossbeam and lathe bed, the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet is connected with control system.

This control method is earlier with a pair of permanent magnet, utilize coil windings to twine and form the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet that control gantry crossbeam suspends, by the electric vortex type displacement sensor in the control system suspension situation of gantry crossbeam is sampled then, then information is transmitted in the dsp controller by A/D converter, after by dsp controller this information and predefined information being compared calculating, by D/A converter and power amplifier the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet on the crossbeam of gantry is adjusted accurately again, finished control gantry crossbeam suspension situation.

At machine industry, in order to adapt at a high speed and the needs that accurately cut, good control system can make magnetic suspension system have strong functions, and the design of controller is one and has much challenging work.Reason is that in the engineering practice, the accurate model of magnetic suspension system often is difficult to obtain, even set up accurate model sometimes, also must simplify because of too complicated.Along with the variation of system works condition and the aging or damage of control element, the characteristic of controll plant also can change thereupon, thus the nominal characteristic of off-design time institute foundation.For High-speed machining, in the working angles because of surface of the work and material hardness is inhomogeneous, cutter acutance and cutting depth change and all can cause machining condition to change often.In addition, under many operating modes, only know that noise or external disturbance belong to certain set and and do not know its exact nature.So for whole lathe, magnetic suspension control system not only will be kept stable operation, also need to adapt to different service conditions, and want to deal with various burst accidents.Maglev control system must have good adaptive capacity to these uncertain factors.In process, can utilize the input/output information of controlled system on the other hand by online real-time adjustment control parameter optimization control system on the one hand, the lathe running status is carried out on-line monitoring.In sum, the magnetic suspension control system performance is the key factor of decision whole system dynamic and static performance, and reasonably CONTROLLER DESIGN and control device for guaranteeing that the stability of a system and reliability have great important.

The invention has the advantages that magnetic suspension system adopts the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet, for large-sized numerical control boring and milling machine gantry magnetic suspension system, the electric current that flows through the suspension magnetic pole when stablizing can be bigger, makes the power consumption of suspension magnetic pole also very big.So adopt permanent magnetism and electromagnetic hybrid suspension system can keep the static balancing of system, thereby significantly reduce the capacity of suspended power supply, reduced the power attenuation of system widely by the magnetic force that permanent magnet provides.It is the numerical control system of core that the magnetic suspension control device adopts with the DSP device, thereby has very fast data-handling capacity and good extended capability, has overcome analog controller and is the defective of the digitial controller of core with the single-chip microcomputer; And assurance is calculated and the real-time of control; Thereby guarantee levitation gap height and stiffness characteristics, be able to take various coupled interference and load disturbance, and have strong robustness, realized significantly reducing the purpose that rubs at last.

In addition, because magnetic suspension system itself has been a time-dependent system, after the suspension magnetic pole added the permanent magnetism part, the destabilizing factor of system increased.Simultaneously, gantry suspension system that is used to carry axis system is a high precision high rigidity magnetic suspension height navigation system, this is a complex nonlinear control, as high-precision processing machine tool, during machine tooling, beyond doubt suspension system is caused a strong jamming, how to eliminate influence fast, make suspension system have high rigidity, keep strong robustness hoverheight, guarantee machining accuracy, this is the control problem that must solve.

In addition, in the control method of the present invention, PID control is one of strategy most widely used in the Industry Control, and the optimization of the PID controller parameter in the dsp processor directly influences the quality of control effect, and and safety, the economical operation of system inseparable relation is arranged.The present invention adopts the control method of genetic algorithm to carry out parameter optimization, and this method is a kind of without any need for initial information and can seek globally optimal solution, efficient optimization combined method.

Adopt genetic algorithm control method to carry out adjusting of three coefficients of PID controller, have the following advantages:

(1) compare with expert's method of adjusting, it has easy to operate, fireballing advantage, does not need complex rule, only duplicates simply, intersects, makes a variation by word string, just can reach optimizing.Avoided expert's method mid-early stage a large amount of knowledge base housekeeping and a large amount of emulation experiments of adjusting.

(2) genetic algorithm control method is to begin parallel work-flow from many points, carries out efficient heuristic search in solution space, has overcome from the drawback of single-point and the blindness of search, thereby has made optimizing speed faster, has avoided being absorbed in too early optimal solution.

(3) genetic algorithm control method is not only applicable to the single goal optimizing, and is applicable to the multiple target optimizing.According to different control systems, at one or more control targets, genetic algorithm all can be sought suitable parameters within the limits prescribed.

(4) genetic algorithm control method still can search out suitable parameters not needing to provide under the situation of adjuster initial parameter, and the control target is met the demands.

Description of drawings:

Fig. 1 represents overall structure schematic diagram of the present invention;

Fig. 2 represents the structural representation of electromagnet and permanent magnet mixed magnetic pole suspending electromagnet of the present invention;

Fig. 3 represents the structured flowchart of control system of the present invention;

Fig. 4 represents the connecting circuit of dsp controller of the present invention and analog-digital converter and digital to analog converter;

Fig. 5 represents the connecting circuit figure of dsp controller of the present invention and JTAG emulator;

Fig. 6 represents the PWM wave generator circuit figure in the power amplifier of the present invention;

Fig. 7 represents photoelectric isolating circuit, power driving circuit and the suspension system circuit diagram in the power amplifier of the present invention;

Fig. 8 represents the main program control flow chart in the dsp controller of the present invention.

Fig. 9 represents the pid parameter main program control flow chart of adjusting of the genetic algorithm in the dsp controller of the present invention.

The specific embodiment: the present invention is described further below in conjunction with accompanying drawing:

As shown in Figure 1, the invention provides a kind of plane milling and boring machine that adopts electromagnet and permanent magnet mixed magnetic pole suspending, mainly comprise lathe bed 6 and gantry crossbeam 2 that can relatively move with lathe bed, be provided with the linear advancement system 3 that advances gantry crossbeam 2 and lathe bed to relatively move between described lathe bed 6 and gantry crossbeam 2; On described gantry crossbeam 2, also be provided with electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5, electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 is arranged on gantry crossbeam 2 towards a side on edge, 6 end of lathe bed, and electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 is connected with control system.Label 1 is a spindle servo unit among Fig. 1, and 7 is workbench, and 8 is cutter.

Described linear advancement system 3 is a permanent magnet linear synchronous motor, this permanent magnet linear synchronous motor mover be arranged on gantry crossbeam 2, its stator is fixed on the lathe bed 6; Between described gantry crossbeam 2 and lathe bed 6, also be provided with guiding electromagnet 4, described guiding electromagnet 4 is arranged on gantry crossbeam 2 on the position of lathe bed 6 both sides, guiding electromagnet 4 is used for controlling gantry crossbeam 2 and advances according to predetermined motion track, by spacing towards the position of lathe bed 6 both sides, it does not depart from the track that advances and moves to make gantry crossbeam 2.

As shown in Figure 2, described electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 is for having the magnet that is tied with hot-wire coil of permanent magnetism magnetic pole; Described permanent magnetism magnetic pole is arranged on the position near edge, 6 end of lathe bed.

Shown in Figure 2, the floated digital-control boring-milling machine in gantry, adopt electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 structures to realize,, make the power consumption of suspension magnetic pole also very big because large-sized numerical control boring and milling machine gantry magnetic suspension system in the past flows through the electric current of suspension magnetic pole when stablizing bigger; And adopt permanent magnetism of the present invention and electromagnetic hybrid suspension system to produce most of suspending power by permanent magnet, thereby significantly reduce the capacity of suspended power supply, reduced the power attenuation of system widely, and the magnetic force that electromagnet provides can keep the dynamic equilibrium of system.The represented structure name of number in the figure is called: 9---lathe bed, and 10---the permanent magnet part, 11---electromagnet is wound with the hot-wire coil part, and 12---air-gap flux, 13---levitation gap; 14---dsp controller, 15---the electric vortex type displacement sensor, 16---coil resistance, 17---power amplifier.

As shown in Figure 3, described control system comprises JTAG emulator, dsp controller, D/A converter, A/D converter, power amplifier and electric vortex type displacement sensor; Described JTAG emulator is connected to dsp controller, and dsp controller is connected to D/A converter, and D/A converter is connected to power amplifier, and power amplifier is connected to the hot-wire coil of electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 and the hot-wire coil of guiding electromagnet 4; Described power amplifier is connected to the hot-wire coil of electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 and the hot-wire coil of guiding electromagnet 4 by coil resistance; Be provided with the electric vortex type displacement sensor between described electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 and the lathe bed 6, also be provided with the electric vortex type displacement sensor between described guiding electromagnet 4 and the lathe bed 6, the electric vortex type displacement sensor is connected to dsp controller by A/D converter.The JTAG replicating machine links to upper industrial computer when using, upper industrial computer is responsible for sending the hoverheight signal, dsp controller is responsible for the processing of given signal and feedback signal and the real-time controller parameters setting of propagation algorithm are calculated, the change-over panel of D/A converter can realize that the two-way digital controlled signal is converted to analog signal, power amplifier is realized analog control signal power amplification and drives levitating electromagnet that the change-over panel of A/D converter can be realized the Analog signals'digital conversion of two-way gap and send back dsp controller.

Fig. 4 is the connecting circuit of dsp controller and analog-digital converter and digital to analog converter; Fig. 5 is dsp controller and JTAG emulator connecting circuit.Wherein dsp controller is selected the high floating point processor of performance price comparison for use, and its model can be TMS320VC33 as shown in Figure 4, and analog-digital converter is selected the TLV2548 shown in Fig. 4 for use, and digital to analog converter is selected the TLV5619 shown in Fig. 4 for use.Wherein digital to analog converter is above-mentioned A/D converter, and analog-digital converter is a D/A converter.

Shown in Fig. 6 and 7, power amplifier comprises PWM wave generator circuit, photoelectric isolating circuit, power driving circuit and suspension system main circuit.

Fig. 6 is the PWM wave generator circuit, selects generation and the control chip of the integrated chip TL494 of pulsewidth modulation as pwm signal among the figure for use,

Fig. 7 is photoelectric isolating circuit, power driving circuit and suspension system main circuit.The PWM waveform of circuit output is used for controlling the conducting/shutoff of half-bridge power amplifying circuit switching device among Fig. 6, for preventing the influence of power amplifying part to control signal, before outputing to switching device, pwm signal two parts circuit is separated with photoisolator, as shown in Figure 7, the photoelectric isolated chip that the present invention selects for use is 6N137, mainly forms photoelectric isolating circuit by this photoelectric isolated chip.

Switching device adopts insulated gate bipolar transistor IGBT in the main circuit of suspension system, IGBT is a kind of device that is combined into by bipolar transistor and MOSFET, it had both had the grid voltage control high-speed switch characteristic of MOSFET, had the characteristics of big current handling capability of bipolar transistor and low saturation voltage drop again.Label is that V1, V2, V3 and V4 are 4 IGBT among Fig. 7, and they have formed the main circuit of suspension system.

The IR2110 that the present invention selects for use is a kind of novel IGBT driver module, required peripheral discrete component seldom, this chip also has self-protection function simultaneously, and is simple by its driving circuit structure that constitutes.

The suspension system main circuit is to be used for inverter circuit to electromagnet power supply.Electromagnet wherein has permanent magnet with inductance and equivalence unshakable in one's determination on it.Owing to need direct current during work of electromagnet, so V2 and V3 are in not on-state all the time, so do not add drive circuit.The operation principle of suspension system main circuit is that the ON time by control loop control IGBT is the duty voltage at regulating magnet two ends recently, obtain desirable electromagnetic attraction and permanent magnetism power with joint efforts.After drive circuit sent Continuity signal, V1 and the energising of V4 conducting electromagnet because the lag time constant of electromagnet is big, can not suddenly change so electric current rises gradually.Producing enough suction after reaching certain electric current constantly diminishes up to reaching set-point the air gap between electromagnet and the rail, suction also increases thereupon when electric current continues to increase, make air gap less than set-point, at this moment drive circuit action, turn-off V1 and V4, electric current in the electromagnet can not suddenly change, electric current will be by diode VD2, the VD3 afterflow, and added voltage is zero on the electromagnet, at this moment the electric current in the electromagnet descends gradually, its suction also descends thereupon, and it is big that the air gap between magnet and the guide rail becomes along with reducing of suction thereupon, when greater than set-point, drive circuit moves once more, repeats the above-mentioned course of work.

The magnetic suspension system of this invention adopts the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet and since this invention at be large-sized numerical control boring and milling machine gantry magnetic suspension system, this system flows through the suspension magnetic pole when stablizing electric current is bigger, makes the power consumption of suspension magnetic pole also very big.So adopt permanent magnetism and electromagnetic hybrid suspension system to produce most of suspending power, thereby significantly reduce the capacity of suspended power supply by permanent magnet.This electromagnet and permanent magnet mixing magnetic suspension system, the magnetic force that is provided by permanent magnet can keep the static balancing of system, reduced the power attenuation of system widely, and the magnetic force that electromagnet provides can keep the dynamic equilibrium of system.

When passing through electric current in the winding of electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5, can strengthen the metal bed ways are produced electromagnetic attraction, magnet applies downward power to bed ways, because the interaction principle of power, bed ways also have power upwards to electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5, because electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 all is to be fixed on mobile gantry crossbeam 2, as long as the electric current in control electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 windings, gantry crossbeam just can be suspended in the air, is in poised state.And linear advancement system 3 is as guidance system, and its principle is similar to suspension system, and it also is the horizontal displacement of controlling suspension gantry by the control electromagnet.

Basic demand to the control that suspends is that control system will have quick response, steady, the anti-interference good performance characteristics of dynamic process, and wherein anti-interference is particularly important.

Analog circuit can be all adopted in the realization of control system, also can adopt with digital circuit.The analog circuit control accuracy is low, be affected by the external environment big, and is difficult for realizing complicated control algolithm, debug difficulties.Traditional digitial controller adopts the single-chip microcomputer of higher gears to realize complicated calculating and control mostly, but the real-time variation is difficult to obtain the better dynamic performance.The DSP device is a kind of microprocessor that is specially adapted to the Digital Signal Processing computing, with the DSP device is that the control core system has very fast data-handling capacity and good extended capability, has overcome analog controller and is the defective of the digitial controller of core with the single-chip microcomputer.The present invention adopts digital DSP control technology, both can guarantee the real-time calculating and control, can give full play to numerically controlled plurality of advantages again.

Control circuit comprises connecting circuit, dsp controller and the JTAG emulator connecting circuit of connecting circuit, dsp controller and the digital to analog converter of dsp controller and analog-digital converter.

Working control situation according to system, after the more multiple scheme, the present invention adopts pulsewidth modulation (PWM) type power amplifier, selects for use the TL494 chip to produce the PWM waveform, in order to prevent that forceful electric power district signal from scurrying interference to returning of light current district, the pwm signal that produces is carried out photoelectricity isolate.Bridge type inverse partly adopts half-bridge structure, and the signal that carries out after the power amplification is directly inputted in the solenoid, and drive coil produces enough electromagnetic forces makes the buoyant element of system realize reliable and stable suspension.

Control method of the present invention is realized by the program that embeds in the dsp processor, this method is earlier with single permanent magnet, utilize coil windings to twine and form the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 that control gantry crossbeam 2 suspends, by the electric vortex type displacement sensor in the control system suspension situation of gantry crossbeam 2 is sampled then, then information is transmitted in the dsp controller by A/D converter, after by dsp controller this information and predefined information being compared calculating, by D/A converter and power amplifier the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 on gantry crossbeam 2 is adjusted accurately again, finished control gantry crossbeam 2 suspension situations.

As shown in Figure 8, its control procedure peace following steps are carried out:

Step 1, dsp controller carry out system initialization;

Whether step 2, the plane milling and boring machine that detects this employing electromagnet and permanent magnet mixed magnetic pole suspending have the ending request signal; If there is the ending request signal to forward step 13 to; If do not have the ending request signal then continue;

Whether the plane milling and boring machine of step 3, the whole employing electromagnet and permanent magnet mixed magnetic pole suspending of detection has interrupt request singal;

If step 4 there is not interrupt request singal, then wait for and interrupting, go back to step 3;

If step 5 interrupt to arrive, reading, and start analog-digital converter, the information of the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet 5 that the electric vortex type displacement sensor is gathered is transmitted in the dsp controller by analog-digital converter;

Step 6, in dsp controller, carry out calculating based on the adjust control algolithm of pid parameter of genetic algorithm;

Step 7, whether testing result has overflows;

Overflow if step 8 has, get extreme value, return step 7;

If step 9 is not overflowed, testing result whether be on the occasion of;

If whether step 10 result is negative value, negate;

If step 11 result whether be on the occasion of, the result is carried out exporting after the digital-to-analogue conversion and by power amplifier;

Step 12, interruption are returned, and go back to step 2.

Step 13, end.

As shown in Figure 9, wherein the adjust concrete steps of control algolithm of pid parameter of the genetic algorithm in the above-mentioned steps six are:

Operation one, determine the approximate range and the code length of each parameter, encode; Determine parameter area, this scope can be given by the user, by the requirement of precision, it encoded then.Choose the binary system word string and represent each parameter, and foundation and relationship between parameters.Binary string is coupled together again and just form a long binary system word string, this word string is the manipulable object of genetic algorithm.

Operation two, produce n individual formation initial population P (0) at random; Because need programming to realize each process, so adopt computer random to produce initial population.At binary coding, earlier produce 0～1 between equally distributed random number, represent 1 between representing 0,0.5～1 between the random number 0～0.5 that regulation produces then.In addition, the complexity of considering calculating is come the size of regulation population.

Operation three, calculating target function value with each individual decoding corresponding parameters value in the population, are asked cost function value J with this parameter;

Operation four, calculating adapt to functional value f, get

General optimization method can be in the hope of the one group of parameter that satisfies condition under constraints, and one of searching is best from this group parameter in design.The index of weighing a control system has three aspects, i.e. stability, accuracy and rapidity.And the rise time has been reflected the rapidity of system, and the rise time is short more, and it is just fast more that control is carried out, and system quality is also just good more.If pursue the dynamic characteristic of system merely, the parameter that obtains is likely that control signal is excessive, can cause system's instability because of saturated characteristic intrinsic in the system in actual applications, and is excessive in order to prevent to control energy, adds controlled quentity controlled variable in object function.Therefore in order to make the control better effects if, controlled quentity controlled variable, sum of errors rise time as constraints.Because it is relevant with object function to adapt to function, so after object function is determined, directly it is carried out parameter optimization as adaptive function.When optimum control parameter just is f (x) maximum under satisfying constraints, the pairing controller parameter of x.

For obtaining satisfied transient process dynamic characteristic, the minimum target function that adopts Error Absolute Value time integral performance indications to select as parameter.Excessive in order to prevent to control energy, in object function, add the quadratic term that control is imported.The optimum index that selecting type (1) is selected as parameter:

$J={\&Integral;}_0^{\&infin;}\left({\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400022.png,DEST\_PATH\_HSB00000224334400031.png"\; state="\{\{state\}\}">w</figure-callout>}}_1\right|e\left(t\right)|+w_2{u}^2\left(t\right))\mathrm{dt}+{\mathrm{<figure-callout\; id="3"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400011.png,DEST\_PATH\_HSB00000224334400022.png"\; state="\{\{state\}\}">w</figure-callout>}}_3\&CenterDot;t_u$

(1)

In the formula, e (t) is a systematic error, and u (t) is controller output, t _uBe the rise time, w ₁, w ₂, w ₃Be weights.For fear of overshoot, adopted punitive function, promptly in case produce overshoot, with overshoot as optimum index, this moment, optimum index was:

$\mathrm{if\; ey}\left(t\right)<0J={\&Integral;}_0^{\&infin;}\left({\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400022.png,DEST\_PATH\_HSB00000224334400031.png"\; state="\{\{state\}\}">w</figure-callout>}}_1\right|e\left(t\right)|+w_2{u}^2\left(t\right)+{\mathrm{<figure-callout\; id="4"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400011.png,DEST\_PATH\_HSB00000224334400022.png"\; state="\{\{state\}\}">w</figure-callout>}}_4|\mathrm{ey}\left(t\right)\left|\right)\mathrm{dt}+{\mathrm{<figure-callout\; id="3"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400011.png,DEST\_PATH\_HSB00000224334400022.png"\; state="\{\{state\}\}">w</figure-callout>}}_3\&CenterDot;t_u$

(2)

In the formula, w ₃Be weights, and w ₄＞＞w ₁, ey (t)=y (t)-y (t-1), y (t) is controlled device output.

Operate five, determine formula sampling selection;

Operate six, carry out the single-point intersection;

Operation seven, evenly variation, operator is operated population P (t), produces population P of future generation (t+1); At first the definite formula sampling of utilization selection mode is selected, and promptly tries to achieve adaptation value by adaptive function, and then asks the corresponding selection probability of each string, and what the selection probability was big will have more descendants in a generation, then can be eliminated on the contrary; According to the expectation breeding number N of each individuality in the selection probability calculation colony that determines in colony of future generation _iThereby, determine the whole individualities in the population of future generation fully.Next carries out the single-point intersection, and crossover probability is P _cIn the member after duplicate with P _cProbability choose word string and form match-pool, then the member of match-pool is mated at random, the position of intersection also is to determine at random.At last with probability P _mMake a variation.

Whether do operation eight, detection genetic algebra satisfy setting value? if do not satisfy, repetitive operation three and operation four restrain or reach predetermined index until parameter; Initial population is by the population of new generation of selecting, intersecting and variation obtains, and the adaptive function of this generation population substitution after decoding is observed and whether satisfied termination condition, if do not satisfy, then repeating step three and step 4 operation is till satisfying.Termination condition is decided by particular problem, as long as each target component in prescribed limit, then stops calculating.

Utilize specific embodiment that the control algolithm that genetic algorithm of the present invention is adjusted pid parameter is described below.

Embodiment:

Step 1, defined variable, initiation parameter.

Parameter K _PSpan be [0,300], K _ISpan be [0,10], K _DSpan be [0,8]; Chromosome adopts binary coding, and length is 10.Population size M=50, genetic algebra G=100, coded strings length l=20, crossover probability and variation probability are respectively: P _c=0.9, P _m=0.1.Step 2, produce n=50 the individual initial population P (0) of formation at random;

Step 3, calculating target function value.With each individual decoding corresponding parameters value in the population, ask target function value J with this parameter.

For obtaining satisfied transient process dynamic characteristic, the minimum target function that adopts Error Absolute Value time integral performance indications to select as parameter.Excessive in order to prevent to control energy, in object function, add the quadratic term that control is imported.The optimum index that selecting type (1) is selected as parameter:

$J={\&Integral;}_0^{\&infin;}\left({\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400022.png,DEST\_PATH\_HSB00000224334400031.png"\; state="\{\{state\}\}">w</figure-callout>}}_1\right|e\left(t\right)|+w_2{u}^2\left(t\right))\mathrm{dt}+{\mathrm{<figure-callout\; id="3"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400011.png,DEST\_PATH\_HSB00000224334400022.png"\; state="\{\{state\}\}">w</figure-callout>}}_3\&CenterDot;t_u---\left(1\right)$

In the formula, e (t) is a systematic error, and u (t) is controller output, t _uBe the rise time, w ₁, w ₂, w ₃Be weights.For fear of overshoot, adopted punitive function, promptly in case produce overshoot, with overshoot as optimum index, this moment, optimum index was:

$\mathrm{if\; ey}\left(t\right)<0J={\&Integral;}_0^{\&infin;}\left({\mathrm{<figure-callout\; id="1"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400022.png,DEST\_PATH\_HSB00000224334400031.png"\; state="\{\{state\}\}">w</figure-callout>}}_1\right|e\left(t\right)|+w_2{u}^2\left(t\right)+{\mathrm{<figure-callout\; id="4"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400011.png,DEST\_PATH\_HSB00000224334400022.png"\; state="\{\{state\}\}">w</figure-callout>}}_4|\mathrm{ey}\left(t\right)\left|\right)\mathrm{dt}+{\mathrm{<figure-callout\; id="3"\; label="w"\; filenames="DEST\_PATH\_HSB00000224334400011.png,DEST\_PATH\_HSB00000224334400022.png"\; state="\{\{state\}\}">w</figure-callout>}}_3\&CenterDot;t_u---\left(2\right)$

In the formula, w ₃Be weights, and w ₄＞＞w ₁, ey (t)=y (t)-y (t-1), y (t) is controlled device output.Get w ₁=1.5, w ₂=0.01, w ₄=5.59, w ₃=2.

Step 4, calculating fitness function value f get

And ordering;

Step 5, determine that formula sampling selects.

If group size is M, i individual fitness function is F _i, the selected Probability p of then individual i _IsFor:

$p_{\mathrm{is}}=\frac{F_i}{\stackrel{M}{\mathrm{\&Sigma;}}{F}_i},(i=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,M)---\left(3\right)$

Calculate the selection probability that can get according to following formula.By the expectation breeding number N of each individuality in the selection probability calculation colony that determines in colony of future generation _iFor:

$N_i=M\&CenterDot;p_{\mathrm{is}}=M\&CenterDot;\frac{F_i}{\stackrel{M}{\mathrm{\&Sigma;}}{F}_i},(i=\mathrm{1,2},\&CenterDot;\&CenterDot;\&CenterDot;,M)---\left(4\right)$

Get N _iInteger part

Determine each corresponding individual existence number in population of future generation (wherein

Expression is not more than the integer of the maximum of x).Can determine in the population of future generation altogether by this step

Individuality.According to N _iFractional part individuality is carried out descending sort, the order get before Individuality joins in the population of future generation.This step can be determined M individuality in the population of future generation fully.

Determine formula sampling system of selection easy realization not only simple to operate, and Select Error is less, can guarantee that the bigger individuality of fitness one is carried in the population of future generation surely.

Step 6, the single-point intersection of carrying out.

In the genetic algorithm, before crossing operation, also must match to the individuality in the colony earlier.The pairing strategy of selecting for use is a random pair, and M the individuality that is about in the colony formed in mode at random

To the pairing group of individuals, interlace operation is to carry out between two individualities of these pairings in group of individuals.Interleaved mode is that single-point intersects, and promptly to each group of individuals to mutual pairing, it is the crosspoint that a certain bits of coded position afterwards is set at random.If individual code length is n, then total (n-1) individual possible position, crosspoint.To each individuality, according to selected crossover probability P to mutual pairing _c=0.9 part coded strings at two individualities of the mutual exchange in its place, crosspoint, thus two new individualities produced.

Step 7, evenly variation.Produce population of future generation.

Selected suitable variation probability P _m=0.1, according to the variation probability each coding of individuality is specified change point, to the change point of each appointment, its encoded radio is done the negate computing, thereby produce a new individuality.

With meeting equally distributed random number in a certain scope, the operating process of replacing the original genic value on each locus in the individual coded strings with a certain less probability is called even variation respectively.Its specific operation process is: according to selected suitable variation probability P _m, and the position of change point in the prescribed coding string.Parameter r when determining evenly to make a variation, r are a random number that meets even probability distribution in [0,1] scope.To each change point, with the variation probability P _m=0.1 gets a random number with certain algorithm in the span of corresponding gene replaces original genic value.

Do step 8, detection genetic algebra G=100 set up not? if be false, rotate back into step 3.

Step 9, end.

Adopt the device and the control scheme of the present invention's design can realize the positioning accuracy height, the disturbance rejection ability is strong, thereby can realize stable suspersion effectively suppressing the suffered interference of system simultaneously preferably.

Claims (7)

1. the plane milling and boring machine of an electromagnet and permanent magnet mixed magnetic pole suspending, mainly comprise lathe bed (6) and gantry crossbeam (2) that can relatively move with lathe bed, be provided with the linear advancement system (3) that driving gantry crossbeam (2) and lathe bed relatively move between described lathe bed (6) and gantry crossbeam (2), it is characterized in that: on described gantry crossbeam (2), also be provided with the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) that gantry crossbeam (2) is upward suspended at lathe bed (6), electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) is arranged on the last side towards lathe bed (6) edge, the end of gantry crossbeam (2), electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) is connected with control system, and described electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) is for having the magnet that is tied with hot-wire coil of permanent magnetism magnetic pole; Described permanent magnetism magnetic pole is arranged on the position near lathe bed (6) edge, the end.

2. the plane milling and boring machine of electromagnet and permanent magnet mixed magnetic pole suspending according to claim 1, it is characterized in that: described linear advancement system (3) is permanent magnet linear synchronous motor, the mover of this permanent magnet linear synchronous motor is arranged on gantry crossbeam (2), and its stator is fixed on the lathe bed (6); Also be provided with guiding electromagnet (4) between described gantry crossbeam (2) and lathe bed (6), described guiding electromagnet (4) is arranged on gantry crossbeam (2) and goes up on the position of lathe bed (6) both sides.

3. the plane milling and boring machine of electromagnet and permanent magnet mixed magnetic pole suspending according to claim 2, it is characterized in that: described control system comprises JTAG emulator, dsp controller, D/A converter, A/D converter, power amplifier and electric vortex type displacement sensor; Described JTAG emulator is connected to dsp controller, dsp controller is connected to D/A converter, D/A converter is connected to power amplifier, and power amplifier is connected to the hot-wire coil of electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) and the hot-wire coil of guiding electromagnet (4); Be provided with the electric vortex type displacement sensor between described electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) and the lathe bed (6), also be provided with the electric vortex type displacement sensor between described guiding electromagnet (4) and the lathe bed (6), the electric vortex type displacement sensor is connected to dsp controller by A/D converter.

4. control method of controlling the plane milling and boring machine of the described electromagnet and permanent magnet mixed magnetic pole suspending of claim 1, it is characterized in that: this method is earlier with a pair of permanent magnet, utilize coil windings to twine and form the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) that control gantry crossbeam (2) suspends, by the electric vortex type displacement sensor in the control system suspension situation of gantry crossbeam (2) is sampled then, then information is transmitted in the dsp controller by A/D converter, after by dsp controller this information and predefined information being compared calculating, by D/A converter and power amplifier the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) on gantry crossbeam (2) is adjusted accurately again, finished control gantry crossbeam (2) suspension situation.

5. the control method of the plane milling and boring machine of electromagnet and permanent magnet mixed magnetic pole suspending according to claim 4, it is characterized in that: the concrete steps of described control method are as follows:

Step 1, dsp controller carry out system initialization;

Whether step 2, the plane milling and boring machine that detects this employing electromagnet and permanent magnet mixed magnetic pole suspending have the ending request signal; If there is the ending request signal to forward step 13 to; If do not have the ending request signal then continue;

Whether the plane milling and boring machine of step 3, the whole employing electromagnet and permanent magnet mixed magnetic pole suspending of detection has interrupt request singal;

If step 4 there is not interrupt request singal, then wait for and interrupting, go back to step 3;

If step 5 interrupt to arrive, reading, and start analog-digital converter, the information of the electromagnet and permanent magnet mixed magnetic pole suspending electromagnet (5) that the electric vortex type displacement sensor is gathered is transmitted in the dsp controller by analog-digital converter;

Step 6, in dsp controller, carry out calculating based on the adjust control algolithm of pid parameter of genetic algorithm;

Step 7, whether testing result has overflows;

Overflow if step 8 has, get extreme value, return step 7;

If step 9 is not overflowed, testing result whether be on the occasion of;

If whether step 10 result is negative value, negate;

If step 11 result whether be on the occasion of, the result is carried out exporting after the digital-to-analogue conversion and by power amplifier;

Step 12, interruption are returned, and go back to step 2.

Step 13, end.

6. the control method of the plane milling and boring machine of electromagnet and permanent magnet mixed magnetic pole suspending according to claim 5 is characterized in that: in described " step 6 " based on the adjust concrete steps of control algolithm of pid parameter of genetic algorithm be:

Step 1, defined variable, initiation parameter.

Step 2, produce n the individual initial population P (0) of formation at random;

Step 3, calculating target function value.With each individual decoding corresponding parameters value in the population, ask target function value J with this parameter.

Step 4, calculating fitness function value f get

And ordering;

Step 5, determine that formula sampling selects.

Step 6, the single-point intersection of carrying out.

Step 7, evenly variation.Produce population of future generation.

Whether do step 8, detection genetic algebra satisfy setting value? if do not satisfy, rotate back into step 3.

Step 9, end.

7. the control method of the plane milling and boring machine of electromagnet and permanent magnet mixed magnetic pole suspending according to claim 6 is characterized in that: the online real-time Tuning PID Controller device parameter of described employing genetic algorithm, select optimum index to be:

$J={\&Integral;}_0^{\&infin;}\left(w_1\right|e\left(t\right)|+w_2{u}^2\left(t\right))\mathrm{dt}+w_3\&CenterDot;t_u$

In the formula, e (t) is a systematic error, and u (t) is controller output, t _uBe the rise time, w ₁, w ₂, w ₃Be weights.For fear of overshoot, adopted punitive function, promptly in case produce overshoot, with overshoot as optimum index, this moment, optimum index was:

$\mathrm{if\; ey}\left(t\right)<0J={\&Integral;}_0^{\&infin;}\left(w_1\right|e\left(t\right)|+w_2{u}^2\left(t\right)+w_4|\mathrm{ey}\left(t\right)\left|\right)\mathrm{dt}+w_3\&CenterDot;t_u$

In the formula, w ₃Be weights, and w ₄＞＞w ₁, ey (t)=y (t)-y (t-1), y (t) is controlled device output.

And during the online real-time Tuning PID Controller device parameter of genetic algorithm, adopt and determine that the formula sampling selects and the single-point interleaved mode.

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