CN1947934A - Active vibration-damping device for cutting equipment, and control method thereof - Google Patents

Abstract

An active vibration damper for lathe is composed of an arbor chuck with cutter, a tool carrier with an arbor chuck fixer on its head and an empty cavity in its tail, a super magnetostrictive executor arranged in said empty cavity and with an output rod connected to said arbor chuck, a high-accuracy vibration sensor arranged on arbor chuck, and a controller connected electrically to said vibration sensor and executor. It can play its vibration damping role in the 5-300 rpm range and has a fast response time less than 0.1 S. Its method is also disclosed.

Description

A kind of active damping device of turning equipment and vibration damping control method

Technical field

The present invention relates to a kind of vibration absorber of turning equipment, especially relate to a kind of active damping device and vibration damping control method of turning equipment.

Background technology

In the lathe grinding process, mainly contain three class vibration sources and influence the machining accuracy of lathe, they be respectively extraneous random disturbances, workpiece to the active force of cutter module, the self-excitation of vibration absorber itself, the method main method of controlling cutting vibration at present comprises Passive Control method and ACTIVE CONTROL method.The Passive Control method is as traditional vibration control mode, mainly be by in system, adding the purpose that the absorbing parts reach the control cutting vibration, come of the vibration of separating vibration source as spring and the damping of fixing by operation parameter to the machinery processing apparatus generation, thus the influence that control or minimizing vibration bring; Simple in structure, the reliable operation of this method is widely used in the engineering, but shortcoming is a shock absorber after design processing, and various performance parameters is malleable not just, in the high frequency stage more satisfactory effect is arranged, but general in medium and low frequency stage vibration control effect; And the ACTIVE CONTROL rule is the principle according to FEEDBACK CONTROL, the change of a certain quantity of state by measuring system, then will with its variable quantity same frequency, with amplitude but anti-phase controlled quentity controlled variable be added on other quantity of state after being added to this quantity of state itself or doing corresponding change.

The mode that scholar both domestic and external in recent years begins to focus on employing active damping in the cutting vibration realizes vibration control, this method can directly apply the active force that can control to controll plant by actuator, thereby offset the vibratory response of the controll plant that causes by vibration source targetedly, reach the purpose that reduces the controll plant vibration amplitude.But present active damping device ubiquity the accurate inadequately problem of control accuracy, has also caused the precision of turning processing not ideal enough thus.

Summary of the invention

Technical problem to be solved by this invention provides a kind of active damping device and vibration damping control method that can improve the turning equipment of turning accuracy.

The present invention solves the problems of the technologies described above the technical scheme that is adopted: a kind of active damping device of turning equipment, comprise knife rest, be fixed with the cutter holder of cutter, vibrating sensor, actuator and controller, the head of described knife rest is provided with the cutter holder holder, described cutter holder is fixedly installed on the described cutter holder holder, the afterbody of described knife rest is provided with cavity, described actuator is arranged in the described cavity, described actuator is provided with and the interconnective take-off lever of described cutter holder, described vibrating sensor is arranged on the described cutter holder, described controller is electrically connected with described vibrating sensor and described actuator, described vibrating sensor is the high accuracy vibrating sensor, described actuator is a giant magnetostrictive actuator, and described cutter holder holder is provided with the flexible hinge structure.

Described flexible hinge structure comprises vibration damping groove and the lightening hole that walks abreast and be provided with described vibration damping groove, be the bull nose that a radius is 18mm-22mm between the lower surface of the front end face of described cutter holder holder and described cutter holder holder, the bottom of described vibration damping groove is the half slot of radius 7mm-8mm, distance between the lower surface of the bottom of described vibration damping groove and described cutter holder holder is 18mm-22mm, the width of described lightening hole is 14mm-16mm, and the wall thickness between described lightening hole and the described vibration damping groove is 13mm-15mm.

In order to obtain desirable gyro rigidity value and minimum working stress, round radius between the lower surface of the front end face of described cutter holder holder and described cutter holder holder is preferably 20mm, the half slot radius of described vibration damping trench bottom is preferably 7.5mm, distance between the lower surface of the bottom of described vibration damping groove and described cutter holder holder is preferably 20mm, the width of described lightening hole is preferably 15mm, and the wall thickness between described lightening hole and the described vibration damping groove is preferably 14mm.

Described giant magnetostrictive actuator comprises overcoat, be provided with electromagnetic actuator device and the mechanical driving device of fixedlying connected in the described overcoat with described cutter holder, the two ends of described overcoat are respectively arranged with base and fastening nut, be provided with demarcation strip between described electromagnetic actuator device and the described mechanical driving device, described electromagnetic actuator device is arranged between described demarcation strip and the described base, described mechanical driving device is arranged between described fastening nut and the described demarcation strip, described demarcation strip is provided with connecting hole, and described electromagnetic actuator device and described mechanical driving device interconnect by described connecting hole.

Described electromagnetic actuator device comprises skeleton and coil, described skeleton is provided with axially extending bore, be provided with magnetostrictive rod in the described axially extending bore, described mechanical driving device comprises take-off lever, the afterbody of described take-off lever passes described connecting hole and described magnetostrictive rod apical grafting, the other end of described take-off lever passes described fastening nut fixedlys connected with described cutter holder, the coaxial pre-compressed spring that is arranged with on the described take-off lever, described take-off lever is provided with the spring-loaded dome, and described pre-compressed spring is arranged between described fastening nut and the described spring-loaded dome.

Described take-off lever front end is provided with and presses closer nut, and described take-off lever is fixedlyed connected with described cutter holder by the described nut that presses closer.

The vibration damping control method of the active damping device of above-mentioned turning equipment, described controller adopts the immune control method based on the immune response theoretical model, offset deviation during wherein system vibration is defined as antigen, the control output signal of described controller is defined as antibody, and the pass between described antigen and the described antibody is:

$u\left(k\right)=\frac{e{\left(k\right)}^2}{{\mathrm{\θ}}^2+e{\left(k\right)}^2}-K_s\·\{1-e^{-\frac{{\left[\mathrm{\Δu}(k-k)\right]}^2}{a}}\}\·e\left(k\right)$

Wherein e (k) represents the antigen value of sampling instant, the value for antibody of the corresponding sampling instant of u (k) expression.

Compared with prior art, the invention has the advantages that and in the range of speeds of 5～300r/min, to play effective damping effect turning vibration, to control response time of cutting vibration in 0.1s, can make the cutting vibration amplitude fading more than 10 decibels, be applied in the lathe grinding vibration control system, can significantly improve the machining accuracy of cutting; The round radius that is provided with between the lower surface of the front end face of cutter holder holder and cutter holder holder is 20mm, the half slot radius of vibration damping trench bottom is 7.5mm, distance between the lower surface of the bottom of vibration damping groove and cutter holder holder is 20mm, the width of lightening hole is 15mm, wall thickness between lightening hole and the vibration damping groove is 14mm, can obtain gyro rigidity value and minimum working stress near ideal value.

Description of drawings

Fig. 1 is the model schematic diagram of knife rest of the present invention;

Fig. 2 is the model schematic diagram of integral body of the present invention;

Fig. 3 is the cross-sectional view of knife rest of the present invention;

Fig. 4 is the structural representation of giant magnetostrictive actuator of the present invention;

Fig. 5 is a fundamental diagram of the present invention;

Fig. 6 is the function relation figure of the FEM model of knife rest of the present invention.

The specific embodiment

Embodiment describes in further detail the present invention below in conjunction with accompanying drawing.

Embodiment one: as shown in the figure, a kind of active damping device of turning equipment, comprise high accuracy vibrating sensor 1, controller 2, giant magnetostrictive actuator (GMA) 3 and knife rest 4, knife rest 4 heads are provided with cutter holder holder 5, cutter holder 8 is fixedly installed on the cutter holder holder 5, cutter 6 is fixing with cutter holder 8 usefulness nuts 7, the afterbody of knife rest 4 is provided with circular groove 9, giant magnetostrictive actuator 3 is arranged on by circular groove 9 and semi-cylindrical groove and covers in the 10 formed cavitys, cutter holder holder 5 be provided with vibration damping groove 52 and with the parallel lightening holes 51 of vibration damping groove 52, the bull nose that is a radius R1=20mm between the lower surface of the front end face of cutter holder holder 5 and cutter holder holder 5, the bottom of vibration damping groove 52 is the half slot of radius R 2=7.5mm, distance D=20mm between the lower surface of the bottom of vibration damping groove 52 and cutter holder holder 5, width B=the 15mm of lightening hole 51, the wall thickness H=14mm between lightening hole 51 and the vibration damping groove 52; Vibrating sensor 1 is arranged on the cutter holder 8, and controller 2 is electrically connected with vibrating sensor 1 and giant magnetostrictive actuator 3.

As shown in Figure 4, giant magnetostrictive actuator 3 comprises overcoat 17, the two ends of overcoat 17 are respectively arranged with base 14 and fastening nut 22, be provided with demarcation strip 24 in the inner chamber of overcoat 17, be provided with skeleton 16 between demarcation strip 24 and the base 14, skeleton 16 is around with coil 19, be provided with rubber ring 15 between skeleton 16 and the base 14, skeleton 16 is provided with axially extending bore, be provided with magnetostrictive rod 18 in the axially extending bore, be provided with take-off lever 20 between demarcation strip 24 and the fastening nut 22, be with pre-compressed spring 21 on the take-off lever 20, the afterbody of take-off lever 20 passes connecting hole and magnetostrictive rod 18 apical graftings on the demarcation strip 24, the other end of take-off lever 20 passes fastening nut 22, and the front end by being arranged on take-off lever 20 to press closer nut 23 cutter holders 8 fixedly connected, take-off lever 20 is provided with spring-loaded dome 25, pre-compressed spring 21 is arranged between fastening nut 22 and the spring-loaded dome 25.

As shown in Figure 5, the operation principle of active damping device is to add man-hour at workpiece 26, workpiece 26 comes in contact with cutter 6 and causes vibration, cause the displacement between workpiece 26 and the cutter 6 to change, be fixed on vibrating sensor 1 on the cutter holder 8 and can record the vibratory output of cutter 6, controller 2 is behind the vibration signal that receives vibrating sensor 1, the output control signal gives giant magnetostrictive actuator 3 with suitable driving voltage, make giant magnetostrictive actuator 3 give 6 one on cutter and direction of vibration opposite effect power by the take-off lever 20 that is fixed on the cutter holder 8, to suppress the Oscillation Amplitude of cutter 6, reach the purpose that the control cutting vibration improves machining accuracy.

In the foregoing description, controller has adopted a kind of immune control method based on the immune response theoretical model, offset deviation during wherein system vibration is defined as antigen, the control output signal of controller is defined as antibody, and the relation between described antigen and the described antibody is formulated as:

$u\left(k\right)=\frac{e{\left(k\right)}^2}{{\mathrm{\θ}}^2+e{\left(k\right)}^2}-K_s\·\{1-e^{-\frac{{\left[\mathrm{\Δu}(k-k)\right]}^2}{a}}\}\·e\left(k\right)$

Wherein e (k) represents the antigen value of certain sampling instant, the value for antibody of the corresponding sampling instant of u (k) expression.

The operation principle of this immune control method is in the immune response theoretical model, and the offset deviation during vibration is regarded as certain external disturbance of system, and the control output signal then is considered to be the control output of the removing interference that produces for the response offset deviation.Immune response is a kind of mechanism of exempting from service based on T cell feedback regulation effect, effect at the different phase T of immune response cell is different, detailed process is the initial stage in immune response, it is little that offset deviation concentration is controlled output signal concentration greatly, the T cell just excites and produces the control output signal, the control output signal will be removed offset deviation gradually, and response process is promoted; In the later stage of immune response, offset deviation concentration is little and control output signal concentration is big, the T cell just suppresses to control the generation of output signal, response process is suppressed, to guarantee immune stability, in the latter stage of immune response, offset deviation concentration and control output signal concentration are all very little, reach the stabilization sub stage of immunity, immune response finishes.

Below at the different knife rest gyro rigidity K of different R2, the D correspondence comparison that performs an analysis, at first by empirical equation F _Z=1610a _p ^F0.84N wherein gets cutting depth a _p=3mm, amount of feeding f=0.1mm/r can obtain radial cutting force F _ZBe 650N, wish during design under this cutting force effect that knife rest at line of action of force the micrometric displacement of 20 μ m takes place, calculate design rigidity value K ₀=650N/20 μ m=32.5 * 10 ³N/mm; Utilize finite element analysis software to set up the FEM model of knife rest respectively then, calculate the gyro rigidity K (R of the knife rest of the corresponding model of difference (R2, D) ₂, D), constructed fuction F=-|K (R again ₂, D)-K ₀|, relation such as accompanying drawing 6, the R as seen from the figure of this function and (R2, D) ₂=7.5mm, during D=20mm, F has maximum, i.e. the gyro rigidity K of this knife rest and design stiffness K ₀Differ minimum, thereby reached desirable gyro rigidity.

Embodiment two: other is with embodiment one, difference is to be between the lower surface of the front end face of cutter holder holder 5 and cutter holder holder 5 bull nose of a radius R1=18mm, the bottom of vibration damping groove 52 is the half slot of radius R 2=7mm, distance D=18mm between the lower surface of the bottom of vibration damping groove 52 and cutter holder holder 5, width B=the 14mm of lightening hole 51, the wall thickness H=15mm between lightening hole 51 and the vibration damping groove 52.

Embodiment three: other is with embodiment one, difference is to be between the lower surface of the front end face of cutter holder holder 5 and cutter holder holder 5 bull nose of a radius R1=22mm, the bottom of vibration damping groove 52 is the half slot of radius R 2=8mm, distance D=22mm between the lower surface of the bottom of vibration damping groove 52 and cutter holder holder 5, width B=the 16mm of lightening hole 51, the wall thickness H=13mm between lightening hole 51 and the vibration damping groove 52.

Claims (7)

1, a kind of active damping device of turning equipment, comprise knife rest, be fixed with the cutter holder of cutter, vibrating sensor, actuator and controller, the head of described knife rest is provided with the cutter holder holder, described cutter holder is fixedly installed on the described cutter holder holder, the afterbody of described knife rest is provided with cavity, described actuator is arranged in the described cavity, described actuator is provided with and the interconnective take-off lever of described cutter holder, described vibrating sensor is arranged on the described cutter holder, described controller is electrically connected with described vibrating sensor and described actuator, it is characterized in that described vibrating sensor is the high accuracy vibrating sensor, described actuator is a giant magnetostrictive actuator, and described cutter holder holder is provided with the flexible hinge structure.

2, the active damping device of a kind of turning equipment as claimed in claim 1, it is characterized in that described flexible hinge structure comprises vibration damping groove and the lightening hole that walks abreast and be provided with described vibration damping groove, be the bull nose that a radius is 18mm-22mm between the lower surface of the front end face of described cutter holder holder and described cutter holder holder, the bottom of described vibration damping groove is the half slot of radius 7mm-8mm, distance between the lower surface of the bottom of described vibration damping groove and described cutter holder holder is 18mm-22mm, the width of described lightening hole is 14mm-16mm, and the wall thickness between described lightening hole and the described vibration damping groove is 13mm-15mm.

3, the active damping device of a kind of turning equipment as claimed in claim 2, it is characterized in that the round radius between the lower surface of the front end face of described cutter holder holder and described cutter holder holder is 20mm, the half slot radius of described vibration damping trench bottom is 7.5mm, distance between the lower surface of the bottom of described vibration damping groove and described cutter holder holder is 20mm, the width of described lightening hole is 15mm, and the wall thickness between described lightening hole and the described vibration damping groove is 14mm.

4, the active damping device of a kind of turning equipment as claimed in claim 1, it is characterized in that described giant magnetostrictive actuator comprises overcoat, be provided with electromagnetic actuator device and the mechanical driving device of fixedlying connected in the described overcoat with described cutter holder, the two ends of described overcoat are respectively arranged with base and fastening nut, be provided with demarcation strip between described electromagnetic actuator device and the described mechanical driving device, described electromagnetic actuator device is arranged between described demarcation strip and the described base, described mechanical driving device is arranged between described fastening nut and the described demarcation strip, described demarcation strip is provided with connecting hole, and described electromagnetic actuator device and described mechanical driving device interconnect by described connecting hole.

5, the active damping device of a kind of turning equipment as claimed in claim 4, it is characterized in that described electromagnetic actuator device comprises skeleton and coil, described skeleton is provided with axially extending bore, be provided with magnetostrictive rod in the described axially extending bore, described mechanical driving device comprises take-off lever, the afterbody of described take-off lever passes described connecting hole and described magnetostrictive rod apical grafting, the other end of described take-off lever passes described fastening nut fixedlys connected with described cutter holder, the coaxial pre-compressed spring that is arranged with on the described take-off lever, described take-off lever is provided with the spring-loaded dome, and described pre-compressed spring is arranged between described fastening nut and the described spring-loaded dome.

6, the active damping device of a kind of turning equipment as claimed in claim 5 is characterized in that described take-off lever front end is provided with to press closer nut that described take-off lever is fixedlyed connected with described cutter holder by the described nut that presses closer.

7, the vibration damping control method of the active damping device of a kind of turning equipment as claimed in claim 1, it is characterized in that described controller adopts the immune control method based on the immune response theoretical model, offset deviation during wherein system vibration is defined as antigen, the control output signal of described controller is defined as antibody, and the pass between described antigen and the described antibody is:

$u\left(k\right)=\frac{{e\left(k\right)}^2}{{\mathrm{\θ}}^2+{e\left(k\right)}^2}-K_S\·\{1-e^{-\frac{{\left[\mathrm{\Δu}(k-d)\right]}^2}{a}}\}\·e\left(k\right)$

Wherein e (k) represents the antigen value of sampling instant, the value for antibody of the corresponding sampling instant of u (k) expression.

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