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The pace introduces into drive system

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Normal Align=left> one, the requirement of numerical control machine tool to feed servo Normal Align=left> 1. Precision tall Normal Align=left> servo should have better static character and taller servo stiffness, achieve taller fixed position precision thereby, in order to make sure the machine tool has minor fixed position error and repeat fixed position error (at present the resolution of feed servo can amount to 1 μ M or 0.

1 μ M, even 0.

01 μ M) . At the same time servo has better dynamic performance even, follow in order to make sure the machine tool has taller outline precision. Normal Align=left> 2. Answer fast, without Normal Align=left> to rise productivity is mixed assure to machine quality, in open, when apply the brake, the requirement is added, decrease acceleration enough big, in order to shorten of servo transfer process time, reduce outline to transfer error. The speed of general electromotor from 0 become highest rotate speed, or fall to be less than 200ms to the time of 0 from top rotate speed. This wants to be answered quickly with respect to requirement servo, but cannot exceed tone again, will formed otherwise cut, the influence machines quality. In the meantime, when laden mutation, the refreshment of requirement speed time also wants short, and cannot have oscillation, such ability get slick treatment surface. Normal Align=left> 3. Timing scope wide Normal Align=left> is in numerical control machine tool, because what use cutting tool, be waited to machine by speed of rotate speed of treatment material, main shaft and feed: Craft requirement has each different, to make sure the for love or money can obtain optimal cutting condition, system of requirement feed drive must be had enough range of wide stepless speed regulation (should be more than 1:1 normally0000) . Be in especially low speed (like <0.

When 01m/min) , should still can flowing move and do not have creeping phenomenon. And high-speed limits requirement can amount to 20~100m/min. Normal Align=left>normal Align=left> 2, the classified Normal Align=left>normal Align=left> 1. The pace enters drive system Normal Align=left> pace enters drive system to close suitably with algorithm of pulse increment interpolation commonly, all choose power pace to regard drive as component into electromotor at present. It is main respond type and Composite two kinds. Reaction type value is inferior, composite price is higher, but the output moment of force that Composite pace enters electromotor is large, running frequency and litre fall rate is rapid, performance is consequently better. Take weakness of syntonic of electromotor low frequency to overcome a situation, raise precision further, appeared the takes fractionize function step with better performance takes electromotor actuating device, received wide application. The pace enters drive system to be transformed in domain of our country economy numerical control and vintage machine tool in had all in all effect. Normal Align=left> 2. Shed Normal Align=left> dc from 20 centuries 70 time arrive 20 centuries 80 time metaphase, dominant position was held in domain of numerical control machine tool. Normal Align=left> big inertia has good wide timing character, its output torsion is big, overload capability is strong. Because electromotor oneself inertia is bigger, comparative with the inertia of machine tool drive disk assembly, accordingly, how does the closed circuit system that makes arrive on the machine tool. Need redo to adjust scarcely (good) is adjusted before wanting to install only, use very convenient. This kind of electromotor deserves to brilliant brake runs unit of fully control or timing of SCR-D of half control bridge mostly. Normal Align=left> is comfortable at machine tool of partial numerical control (wait like drilling machine, punching machine) start often, apply the brake and the requirement that locate quickly, developed dc again electromotor of servo of medium, small inertia and high-power transistor wide modulation of arteries and veins (PWM) actuating device. Because shed servo electromotor to use machine continuously (brush, commutator) inverting, because this is put in a lot of defect. And the timing character with dc servo good electromotor gets through mechanical inverting just about, consequently these defect cannot be overcome. The likelihood when system of dc servo drive is transformed besides old machine tool at present is withheld, other already applied rarely, this book introduces no longer. Normal Align=left> 3. Communicate Normal Align=left> comes for years, people tries to replace dc motive with AC motor all the time, its difficulty depends on AC motor the timing function of motive of very inaccessible dc. Enter 20 centuries after 80 time, because communicate the material of servo electromotor, structure and the revolutionary progress that control theory and method, and the development of microelectronics technology and power semiconductor device, make development of communication actuating device very rapid, already replaced dc servo electromotor at present. Normal Align=left> communication and dc servo electromotor compare the biggest advantage to depend on it needing to safeguard, make simple, agree with to work below harsh environment. Current, communication servo already realized complete digitlization, it is namely in servo, besides drive class, all function all is finished by microprocessor, but the function such as function of control of the make a present of before ground of high speed, real time comes true, compensation, best control, self-study. Normal Align=left> application has communication synchronism electromotor and asynchronous electromotor at the communication servo electromotor of feed drive two kinds big. Because the power of drive of feed of numerical control machine tool is general not big (hundreds to several kilowatt) , and the timing index that communicates asynchronous electromotor is inferior to communicating synchronous electromotor commonly, because this most feed servo uses magneto,communicate synchronous electromotor. Normal Align=left>normal Align=left> 3, the compositive Normal Align=left>normal Align=left> numerical control uses power pace to serve as executive component into electromotor, implementation feed moves. Compare with photograph of closed circuit system, it does not have positional feedback loop and speed feedback loop, do not need to use measurement unit of the position, speed and complex control to adjust consequently circuit, this makes systematic cost is reduced greatly, simple and reliable, deserve easily to receive with the machine tool, control is used convenient. Be opposite consequently speed, precision asked to wide application receives on machine tool of not quite tall medium, small-sized numerical control. Normal Align=left> pace does not have positional feedback loop and speed feedback loop into drive system, use on machine tool of not tall to speed and precision requirement medium, small-sized economy numerical control commonly. Normal Align=center> Normal Align=left>normal Align=left> 4, the control Normal Align=left>normal Align=left> 1.

The control that workbench displacement measures: Normal Align=left> feed displacement of workbench of ψ → machine tool measures electromotor rotor angular displacement L. Can push the pulse equivalent that gets open loop system very quickly accordingly (the workbench displacement of correspondence of pulse of a feed measures) δ : Normal Align=left> type - the pace takes part of electromotor step pitch (° ) ; Normal Align=left> H - (Mm) ; Normal Align=left> I - the decelerate of decelerate gear is compared. Normal Align=left> 2.

Workbench feed speed controls: Normal Align=left> system magnifies / cut off the power the frequency that condition changes, decided the pace enters the rotate speed ω of electromotor rotor consequently, after gear of decelerate of this ω classics, guide screw, nut, reflect the feed speed V that is workbench. / of electrify of winding of stator of → of F of feed pulse frequency cuts off the power the feed speed V that the pace of → of metabolic frequency F of condition enters workbench of → of ω of electromotor rotate speed. Can obtain V of speed of feed of open loop system to be Normal Align=left> V=60 - the pulse frequency that inputs a pace to enter electromotor (Hz) 3.

Workbench movement way controls: The circular order way that changes a pace to input pulse signal into electromotor, know circular order with respect to what changeable pace receives the electricity in electromotor stator winding, make the pace enters electromotor to implementation is turning and invert thereby, corresponding workbench feed direction is changed. Normal Align=left> input. Normal Align=left>normal Align=left> 5, the pace enters electromotor (1, 2: Brief specification, attention and " servo of numerical control machine tool controls " of course join) Normal Align=left>normal Align=left> 1.

Structural Normal Align=left> pace enters electric machinery by rotor and stator two parts are comprised, issue A of stator of the three-phase in the graph, B, C, three-phase every photograph is polar: AA ' , BB ' , CC ' , every extremely on 5 tine. Normal Align=center>normal Align=center>normal Align=center>normal Align=left> 2.

Working principle 3.

Major attribute 1) step pitch horn and step pitch error turn horn of border step pitch and theory are worth Neigeshi between error. The maximum of the error, call step pitch error. The pace is in normally into the step pitch error of electromotor 10 ' less than. Step pitch part is smaller, control is more accurate. The fixed position precision that step pitch error affects executive part directly 2) when torsion of the biggest static state does not change electrify position into electromotor when the pace, rotor lies not to use position. If be on electromotor axis adscititious a laden torsion, make rotor has turned by certain way an angle, the electromagnetism torsion T that right now rotor place suffers calls static torsion, angle Q calls maladjusted part. The concern of the T when describing a static state and Q calls moment actor character, if pursue,3-3a place is shown. The electromagnetism torsion maximum on this character calls the biggest static torsion. Inside static stability area, when adscititious torsion eliminate, rotor falls in electromagnetism torsion action, still can return steady balance to choose the place. 3) when sky of the frequency that start carries, the pace enters electromotor to be started suddenly by static condition, enter the moves normally highest frequency that does not lose a condition, call the frequency that start or dash forward jump frequency. If the instruction pulse frequency that increases a pace to enter electromotor is more than the frequency that start, cannot work normally. The pace is in into electromotor laden (especially inertial load) the starting frequency below wants than carrying for nothing low, and, increase as load (inside limit) , the frequency that start can be reduced further. The highest frequency that start: The highest frequency that start and pace concern top job frequency into the inertial load of electric machinery: Concern with load, below same load, top job frequency is ambitious Yu Qi uses frequency. 4) after pace of successive running frequency is started into electromotor, its traversal speed can dog to instruction pulse frequency rises continuously and do not lose the top job frequency of the pace, call successive running frequency, its value is ambitious at starting frequency. The property that it also takes load along with electromotor place with size different, also have very big concern with drive power source. 5) quadrature frequency character and T=F of character of frequency of dynamic torsion quadrature (F) be to describe a pace to enter electromotor to stabilize the relation between torsion of the output when moving and successive running frequency continuously. The torsion of correspondence of on this character each frequency calls dynamic torsion. The characteristic that dynamic torsion should consider to drop along with the rise of successive running frequency when using. 6) adding what decelerate character pace enters electromotor to sum decelerate character is to describe a pace to stop into electromotor You Jing working frequency or arrive to be added still by working frequency, in decelerate process, the relation of the frequency change of condition of stator winding electrify and time. The pace enters electromotor litre fast and fall fast character is used quicken time constant Td of constant of Ta and slowdown time will describe, if pursue,3-3c place is shown. 6, the drive power supply that the pace takes electromotor 1.

Pulse allocation controls pulse allocation to control the electrify run mode that is used at controlling a pace to enter electric machinery, its action is the pulse of one system instruction that delivers numerical control unit according to certain order and cent recipe type is handled, the set up an electric circuit that dominates each photograph winding, cut off the power. 2.

The electric current that the enlarge of TTL n signal that drive magnifies circuit drive magnifies the function of circuit is will annular alloter is given out goes to ten to a few. Send to the pace to enter each winding of electromotor. Be like next requirements into electromotor drive circuit to the pace commonly: 1) can provide the excitation electricity of the adjacent and rectangular wave with around nice edge; The power comsumption of itself of 2) drive circuit small, efficiency is tall; 3) cost is inferior and facilitating maintenance; 4) can stabilize reliable ground to move. 7, the pace enters electric machinery choose 1.

Chosen principle: 1) Q of pace moment actor and mechanical system photograph match, the D that needs in order to get systematic place; 2) make sure electric machinery outputs torsion, be more than laden place to need torsion; 3) can match with the laden inertia photograph of mechanical system; 4) cutting of can contented workbench machines electric machinery traversal speed and top job frequency and move quickly requirement. 2.

Chosen measure: 1) the kind that should decide the pace enters electromotor above all. 2) according to the treatment of the machine tool precision asks, the pulse equivalent that chooses feed axis 3) the pitch of the step pitch part that takes electromotor according to picking a pace, guide screw and ask pulse equivalent, of computational decelerate gear fall speed ratio. 4) electromotor is when the rapiddest floating rate, the electromotor that decides by quadrature frequency character outputs torsion to want to be more than laden torsion, take superabundant amount. 5) the pace has very big concern into the starting frequency of electromotor and laden torsion and inertia. CNC Milling