CN102817913A - Air-floatation follow-up device capable of eliminating inertia force influence - Google Patents

Abstract

The invention relates to an air-floatation follow-up device capable of eliminating inertia force influence, which comprises an air-floatation shaft, two air-floatation sleeves and a long-distance guide rail air-floatation pulley, wherein the air-floatation sleeves are sleeved on the air-floatation shaft and both tightly connected with an air storage sleeve which is fixedly connected with a connecting rod, the connecting rod is fixedly connected with the air-floatation pulley, an air inlet is arranged in the axis of the air-floatation pulley, a hanging rope is sleeved on the air-floatation pulley, and a moving piece is hung on the hanging rope; a photoelectric coded disk of a photoelectric decoder is arranged on the air-floatation pulley, and a reading head of the photoelectric decoder is arranged on a connecting rack and just opposite to the photoelectric coded disk; an electromagnetic force generating mechanism comprises an electromagnet and a permanent magnet, wherein the electromagnet is arranged in an installation seat, and the permanent magnet is arranged on the air storage sleeve and just opposite to the electromagnet. The air-floatation follow-up device effectively eliminates the inertia force influence and has higher control precision.

Description

Eliminate the air-floation follow-up device of inertia force influence

Technical field

The present invention relates to air-floation follow-up device, especially a kind of air-floation follow-up device of eliminating inertia force influence.

Background technique

The suspending way that adopts at present is that weight (movement parts) is directly hung on the slide block on the linear rail through hanging rope, and slide block is followed the movement parts servo-actuated.But when high-acruracy survey, the frictional force between linear rail and slide block can be to the spatial position of movement parts and the influence of motion generation additional forces.On the other hand, because movement parts is connected on the slide block, slide block and other are hung follow-up unit all has quality, in follow-up unit accompany movement part movement process, can produce inertial force, and this inertial force will append on the movement parts.

Long in order to realize apart from frictionless motion; Number of patent application be CN's 201010165536.0 " being used for the friction-free air floating device that extra long distance is followed the suspension centre movement locus " a kind of friction-free air floating device that extra long distance is followed the suspension centre movement locus that is used for is provided; This patent will axially be grown the no frictional movement grafting of distance to the slide block guide rail assembly of general motion precision, can realize that air supporting is enclosed within the floating axle of losing heart and does big displacement with movement parts and move.But; Brought new problem, the quality of the air-floation follow-up device that two air supporting covers and air storage cover are formed is very big, quickens or during retarded motion in movement parts; Air-floation follow-up device and other are hung the inertia force influence of follow-up unit and can not be ignored; This moment, only passive following can not be satisfied accurate requirement of following the suspension centre movement locus synchronously, need measure tracking error, managed to remove this The Effect of Inertia Force.

Summary of the invention

Can not eliminate inertia force influence, deficiency that control accuracy is lower for what overcome existing air-floation follow-up device, the present invention provides the air-floation follow-up device of the higher elimination inertia force influence of a kind of effective elimination inertia force influence, control accuracy.

The technical solution adopted for the present invention to solve the technical problems is:

A kind of air-floation follow-up device of eliminating inertia force influence comprises air-bearing shafts, air supporting cover and long apart from guide rail air supporting pulley, and said air supporting cover is sleeved on the said air-bearing shafts; Said air supporting is with two; Said air supporting cover all is tightly connected with the air storage cover, is gas storage chamber between said air storage cover and the air-bearing shafts, and the axle center of said air-bearing shafts has gas-entered passageway; One end of said gas-entered passageway connects main air supply pipe; The other end of said gas-entered passageway is communicated with said gas storage chamber, and said gas storage chamber is provided with the air outlet, and said air outlet is communicated with the suction port of each air supporting cover through connecting tracheae; Said air storage cover is fixedly connected with connecting rod; Said connecting rod is fixedly connected with the air supporting pulley, and the axle center of said air supporting pulley has inlet hole, and said inlet hole is communicated with the said tracheae that is connected; Suit hanging rope on the said air supporting pulley, said movement parts are lifted on the said hanging rope; Said air-floation follow-up device comprises that also being used to detect the photoelectric encoder that whether occurs tilting between hanging rope and the air storage cover produces mechanism with the electromagnetic force that is used to offset inertia force influence; The photoelectric coded disk of said photoelectric encoder is contained on the said air supporting pulley; The read head of said photoelectric encoder is contained on the said link press span, and the read head of said photoelectric encoder is over against photoelectric coded disk; Said electromagnetic force produces mechanism and comprises electromagnet and permanent magnet, and on said electromagnet was contained in the fitting seat, said permanent magnet was contained in air storage and puts, and said permanent magnet is over against said electromagnet.

Further, said electromagnet is contained in the fitting seat left end, and said permanent magnet is contained in air storage cover right-hand member.Certainly, also can adopt other fit, get final product as long as electromagnet, produces electromagnetic force over against electromagnet.

Further again; The two ends of said air-bearing shafts are set with fitting seat; Said fitting seat is fixedly connected with said slide unit, and said slide unit is connected to long apart from the linear rail, and the grating chi is contained in air storage cover neutral position; Grating ruler reading head is contained in the fitting seat neutral position, and said grating ruler reading head is over against the grating chi.

Technical conceive of the present invention is: air-floation follow-up device does not have the friction servo-actuated according to the movement parts hoisting point position; Detect air storage cover position through the grating chi; If the positional value that the grating ruler reading head on the fitting seat is read is not equal to zero, then driving source such as ACTIVE CONTROL motor moves through synchronous band control slide unit; The relative displacement that guarantees air storage cover and fitting seat is zero, promptly is positioned at the central position of fitting seat.

To the photoelectric encoder zero clearing, air-floation follow-up device and movement parts are followed when consistent before motion, and hanging rope is vertical with the air storage cover, and the photoelectric encoder reading is zero under this state.Movement parts is quickened or during retarded motion along the linear rail direction, because the quality of the air-floation follow-up device that air storage cover and two air supportings covers are formed is bigger, though there is not the influence of frictional force in the accompany movement process; But inevitably to receive the influence of self inertia power; Lag or lead occurs, can not in full accordly follow, hanging rope and air storage cover no longer keeps plumbness under this state; But occur tilting, establishing this angle of inclination is α.See accompanying drawing 4 for details.Be contained in encoder on the air supporting pulley and can measure the size of α delicately; And pass to this angle value the embedded microprocessor of band PID control; Embedded microprocessor calculates the size and the direction of control current of electromagnet according to the pid parameter of adjusting; The electromagnet of fitting seat left end produces thrust or the suction opposite with inertial force to the permanent magnet of air storage cover right-hand member, and the air-floation follow-up device that air storage cover and two air supporting covers are formed moves to the left or to the right, thereby reduces the influence of self inertia power to accompany movement; Promptly reduce the tilt angle alpha between hanging rope and the air storage cover, finally make hanging rope and air storage cover keep vertical again.The control system principle sees accompanying drawing 5 for details.

The present invention has well solved owing to increased the quality of air storage cover with the air-floation follow-up device of two air supporting cover compositions in the air-floating apparatus of extra long distance servo-actuated; Therefore the self inertia power that produces can not simply be ignored, and then leans on the passive problem that can not be synchronized with the movement of following merely.The present invention makes initiatively accompany movement part motion of air-floation follow-up device through the power of embedded microprocessor control electromagnet generation with the inertial force opposite sign but equal magnitude, reaches and removes the purpose that air-floation follow-up device self inertia power influences.

Beneficial effect of the present invention mainly shows: do long distance nothing friction servo-actuated in order to realize that air supporting is enclosed within on the floating axle of losing heart according to the movement parts hoisting point position; To axially grow the no frictional movement grafting of distance to the slide block guide rail assembly of general motion precision; Detect air storage cover position by the grating chi; Move by drive sources such as ACTIVE CONTROL motor control slide block; The relative displacement that guarantees air storage cover and mount pad is zero, so just can guarantee that movement parts rubs apart from remaining under the situation of movement not have long.But owing to increased the quality of air-floation follow-up device, the inertial force that therefore produces can not simply be ignored when acceleration of accompany movement part or retarded motion.Hanging rope and air storage cover angle change value that this patent records according to photoelectric encoder; By the power of embedded microprocessor control electromagnet generation with the inertial force opposite sign but equal magnitude; Make initiatively accompany movement part motion of air-floation follow-up device, reach consistent purpose of following.

Description of drawings

Fig. 1 is a kind of air-floation follow-up device mechanical construction drawing of eliminating inertia force influence.

Fig. 2 is the profile of Fig. 1.

Fig. 3 is an air supporting pulley partial enlarged drawing.

Fig. 4 is hanging rope and air storage cover angle of inclination schematic representation when to be that air-floation follow-up device is inconsistent follow.

Fig. 5 is a kind of air-floation follow-up device control principle figure that eliminates inertia force influence.

Embodiment

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

With reference to Fig. 1～Fig. 5, a kind of air-floation follow-up device of eliminating inertia force influence comprises air-bearing shafts 10 gentle empty boastings 2; Said air supporting cover 2 is sleeved on the said air-bearing shafts 10, and said air supporting cover 2 has two, and said air supporting cover 2 all is tightly connected with air storage cover 1; Air storage cover 1 is fixedly connected with air supporting pulley 16; Said fitting seat 8 is contained in said air-bearing shafts 10 two ends, and said air storage cover 1 constitutes air-floation follow-up device, said air-floation follow-up device and movement parts servo-actuated with said air supporting cover 2.The air-floation follow-up device of said elimination inertia force influence also comprises long apart from linear rail 6; Said length is installed in I-shape beam 22 both sides apart from linear rail 6; Slide unit 5 is installed on the I-shape beam 22; Said slide unit 5 is fixedly connected with said fitting seat 8, and said air supporting pulley 16 is connected with said air storage cover 1 through said connecting rod 21.Between said air storage cover 1 and the air-bearing shafts 10 is gas storage chamber; The axle center of said air-bearing shafts 10 has gas-entered passageway; Connect main air supply pipe 19, and be communicated with said gas storage chamber, said gas storage chamber is provided with the air outlet; Said air outlet is communicated with the suction port of each air supporting cover 2 through connecting tracheae 17, and is communicated with the air-bearing shafts of said air supporting pulley 16.

Said position transducer grating chi 3 is installed in air storage cover neutral position, and grating ruler reading head 4 is contained in the fitting seat neutral position, in order to judge that air-floation follow-up device departs from the air-bearing shafts neutral position and whether reaches setting value.

Said electromagnet 9 is installed on the said fitting seat 8, and said permanent magnet 11 is installed in said air storage cover 1.The photoelectric coded disk 14 of said photoelectric encoder is sleeved on the front or the back of said air supporting pulley, zero clearing before motion.Said photoelectric encoder read head 20 is contained on the said connecting rod 21, over against said air supporting pulley front or the back.

Air supporting cover and air storage inner room seal the air storage cover through O type circle.

In the present embodiment, when moved with the direction short distance of air-bearing shafts 10 parallel to an axiss on movement parts 13 edges, the air-floation follow-up device that drags air storage cover 1 and air supporting cover 2 compositions immediately moved axially on air-bearing shafts 10.After relative displacement that position transducer grating chi 3 detects air storage cover 1 and fitting seat 8 is greater than setting value; ACTIVE CONTROL motor 7; Overlap 1 same direction of movement through synchronous band control slide unit 5 by air storage and move, thereby the air-floation follow-up device that assurance air storage cover 1 and air supporting cover 2 are formed is positioned at the neutral position of fitting seat all the time.For the mobile occasion of long distance; ACTIVE CONTROL motor 7 drives slide unit through synchronous band and moves; Spatial position and motion with air storage cover 1 and movement parts 13 impacts because the characteristic of frictionless motion between air supporting cover and the air-bearing shafts, the moving process of slide unit be not to air supporting cover 2.

With reference to accompanying drawing 4,5, when the direction of movement parts 13 edges and air-bearing shafts 10 parallel to an axiss moves; Because the quality of air-floation follow-up device is bigger; Drag when air-floation follow-up device moves and can not ignore its The Effect of Inertia Force, if air-floation follow-up device can not consistently be followed, then hanging rope 12 is no longer perpendicular to air storage cover 1; Occur tilting, the angle of inclination is α.The photoelectric coded disk 14 that is contained in the photoelectric encoder on the air supporting pulley 16 can be measured the size of tilt angle alpha delicately; And pass to this angle value the embedded microprocessor of band PID control; Embedded microprocessor calculates the size and the direction of the electric current of control electromagnet 9 in view of the above; 9 pairs of air storages of the electromagnet of fitting seat 8 left ends are overlapped permanent magnet 11 generations and the air storage of 1 right-hand member and are overlapped opposite thrust or the suction of air-floation follow-up device inertial force that 1 gentle empty boasting 2 is formed; Air-floation follow-up device moves to the left or to the right; Thereby reduce of the influence of self inertia power, promptly reduce the tilt angle alpha between hanging rope and the air storage cover, finally make hanging rope and air storage cover keep vertical again accompany movement.The control system principle sees accompanying drawing 3 for details.

Concrete control algorithm is following:

When the relative displacement of detected fitting seat of grating chi and air storage cover was zero, photoelectric encoder can measure hanging rope and air storage cover angle [alpha] changes, and the quality m of restrict long L and air-floation follow-up device is known.

Linear speed

embedded microprocessor algorithm is following:

If t ₀The angle of inclination of hanging rope constantly and air storage cover is α ₀, the time lag, Δ t was very little, 0.01s for example, t ₁=t ₀The angle of inclination of the hanging rope in+Δ t moment and air storage cover is α ₁, then linear speed is approximately

$v\≈\frac{L\sin {\mathrm{\α}}_1-L\sin {\mathrm{\α}}_0}{t_1-t_0}$

The known linear acceleration

If t0 linear speed constantly is v ₀, t ₁=t ₀+ Δ t linear speed constantly is v ₁, t is very little for Δ, then

$a\≈\frac{v_1-v_0}{t_1-t_0}$

Inertial force $F=m=m\frac{d}{\mathrm{Dt}}\left[\frac{d\left(L\mathrm{Sin}\mathrm{\α}\right)}{\mathrm{Dt}}\right]\≈m\left(\frac{v_1-v_0}{t_1-t_0}\right),$

The number of turn N of electromagnet coil, S is known for the iron core cross-section area, the suction F of electromagnet ₁Formula is derived as follows:

Wherein S is the iron core cross section; μ 0 is a space permeability;

is magnetic flux; For DC electromagnet;

so

${\mathrm{<figure-callout\; id="1"\; label="F"\; filenames="HDA00001987436000012.png,HDA00001987436000013.png"\; state="\{\{state\}\}">F</figure-callout>}}_1=\frac{1}{2{\mathrm{\&mu;}}_0}\frac{I^2{N}^2}{{\mathrm{<figure-callout\; id="2"\; label="R\; m"\; filenames="HDA00001987436000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_m^{}}\frac{1}{S}$

Through the electric current of electromagnet coil, N is the number of turn of electromagnet coil.Because the suction F of electromagnet ₁With the equal and opposite in direction of follower inertial force F, in the opposite direction, then have:

$\frac{1}{{2\mathrm{\&mu;}}_0}\frac{I^2{N}^2}{{\mathrm{<figure-callout\; id="2"\; label="R\; m"\; filenames="HDA00001987436000012.png"\; state="\{\{state\}\}">R</figure-callout>}}_m^{}}\frac{1}{S}\&ap;-m\left(\frac{v_1-v_0}{t_1-t_0}\right),$ Negative sign is represented in the opposite direction.

$I\&ap;\sqrt{m\left(\frac{v_1-v_0}{t_1-t_0}\right)\frac{{2\mathrm{\&mu;}}_0{R}_m^2\mathrm{<figure-callout\; id="2"\; label="S\; N"\; filenames="HDA00001987436000012.png"\; state="\{\{state\}\}">S</figure-callout>}}{N^{}}}$

This patent is realized providing accurate equilibrant force to reduce the influence of air-floation follow-up device self inertia power through the size and Orientation of the angle of inclination sampled value control electromagnet current of hanging rope and air storage cover.The correct prerequisite that realizes of this control algorithm is to guarantee that the relative displacement by detected fitting seat of grating chi and air storage cover is zero, if non-vanishing certainly, then needs the ACTIVE CONTROL motor driving to be connected to the slide unit of fitting seat, and making it to move to relative position is zero place.The variation of the relative displacement of fitting seat and air storage cover has certain disturbance to this control algorithm, needs to consider the influence of this disturbance.

Claims (3)

1. air-floation follow-up device of eliminating inertia force influence; Comprise air-bearing shafts; Air supporting cover and long apart from guide rail air supporting pulley; Said air supporting cover is sleeved on the said air-bearing shafts; Said air supporting is with two; Said air supporting cover all is tightly connected with the air storage cover; Be gas storage chamber between said air storage cover and the air-bearing shafts; The axle center of said air-bearing shafts has inlet channel; One end of said inlet channel connects main air supply pipe; The other end of said inlet channel is communicated with said gas storage chamber; Said gas storage chamber is provided with the gas outlet, and said gas outlet is communicated with the air inlet of each air supporting cover by connecting tracheae; Said air storage cover is fixedlyed connected with connecting rod; Said connecting rod is fixedlyed connected with the air supporting pulley, and the axle center of said air supporting pulley has air admission hole, and said air admission hole is communicated with the said tracheae that is connected; Suit hanging rope on the said air supporting pulley, said movement parts are lifted on the said hanging rope; It is characterized in that: said air-floation follow-up device comprises that also being used to detect the photoelectric encoder that whether occurs tilting between hanging rope and the air storage cover produces mechanism with the electromagnetic force that is used to offset inertia force influence; The photoelectric coded disk of said photoelectric encoder is contained on the said air supporting pulley; The read head of said photoelectric encoder is contained on the said link, and the read head of said photoelectric encoder is over against photoelectric coded disk;

Said electromagnetic force produces mechanism and comprises electromagnet and permanent magnet, and on said electromagnet was contained in the fitting seat, said permanent magnet was contained in air storage and puts, and said permanent magnet is over against said electromagnet.

2. the air-floation follow-up device of elimination inertia force influence as claimed in claim 1 is characterized in that: said electromagnet is contained in the fitting seat left end, and said permanent magnet is contained in air storage cover right-hand member.

3. according to claim 1 or claim 2 the air-floation follow-up device of elimination inertia force influence; It is characterized in that: the two ends of said air-bearing shafts are set with fitting seat; Said fitting seat is fixedly connected with said slide unit, and said slide unit is connected to long apart from the linear rail, and the grating chi is contained in air storage cover neutral position; Grating ruler reading head is contained in the fitting seat neutral position, and said grating ruler reading head is over against the grating chi.

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