CN102679910A - Rotary position detector and relevant method - Google Patents
Rotary position detector and relevant method Download PDFInfo
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- CN102679910A CN102679910A CN2011100660436A CN201110066043A CN102679910A CN 102679910 A CN102679910 A CN 102679910A CN 2011100660436 A CN2011100660436 A CN 2011100660436A CN 201110066043 A CN201110066043 A CN 201110066043A CN 102679910 A CN102679910 A CN 102679910A
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Abstract
The invention discloses a rotary position detector, which comprises a shell with an inner space, wherein a reflection element is arranged in the inner space; a light source upwards emits light rays; a base supports a photodetector component with a first number of ringlike fan-shaped opto-sensors; the ringlike fan-shaped opto-sensors are arranged around the axis of a motor shaft in pairs; a detector element 'A' and a detector element 'B' are alternately arranged; a light interceptor rotates together with the shaft above the photodetector component and the light source and comprises a second number of transparent elements which are arranged around the axis and have the same surface area; the second number is half of the first number; a circuit is used for measuring signal which is from the detector A to the detector B and relevant with the quantity of light falling on the circuit; and the difference between the detector A signal and the detector B signal is relevant with the angular position of the motor shaft.
Description
Technical field
The present invention relates to a kind of rotational position detection device that is used for representing axle or other positions, rotating element angle.More specifically, the present invention relates to thisly be used in motor and based on the position detector on the galvanometric optical scanner.
Background technology
Rotational position detection device has many application, and the position of for example detecting axle on the motor is so that electrical converter.The another kind of application is the position of detecting stretching pulley in tape player or the roll type printing machine, so that on band or paper, keep constant-tension.A more recent application of rotational position detection device is that the position of motor as accelerator pedal (throttle) in the automobile of the part of drive wheels or whole device used in induction.
Be used to immovable input beam target goal zone based on galvanometric optical scanner.This type scanner uses limited rotation motor that rotation is delivered on the optical element of mirror for example.Usually mirror is directly installed on the output shaft of motor.Position detector is included in the motor, near output shaft or be positioned in " back " portion of motor.This position detector is output one curtage signal usually, and this signal is directly proportional with the relative angle of motor drive shaft, thereby relevant with respect to the angle of immovable input beam with mirror.
Be used for mark, cutting or demonstration based on galvanometric optical scanner guided laser bundle, this is most important to positional accuracy and repeatability.Therefore, a limiting factor in accuracy and the repeatability is the performance of the position detector that uses with optical scanner.
In theory, rotational position detection device should be only responsive to the rotation angle of scanner axis.Because mirror is directly connected on the scanner axis, this is the rotation angle of the axle of expression outlet beam direction.Axially-movable and radial motion can not influence the target location through specularly reflected jiong light beam generally speaking; And because this is the target beam position important to scanning system; The output of position detector should be represented target location and insensitive to the things that does not influence the target location, for example axial and radial motion.The dynamic perfromance that axial axle motion can be used as scanner exists.For example, if the magnetic texure of scanner is undesirable, when fierce acceleration and between deceleration period during with the strong current pulse input scanner this axle can outwards or inwardly rise and fall.The radial motion of scanner can be used as the result of defective in generation " noise " or the manufacturing and exists, and this result allows axle that a spot of radial motion is arranged.If rotor is not exclusively concentric with stator component, perhaps attach to inertia load (mirror and the support) incomplete equilibrium of output shaft, the radial axle motion can also exist as dynamic effect.
One servo controller is connected between position detector and the motor.If this position detector provides as axially or a certain output of radial axle motion result, this servo controller with this indefinite output error be interpreted as the variation of turned position, then cause the location mistake of total system.Thus, desirable rotational position detection device will provide as just the output of rotating the result, and can not provide the output as axial or radial motion result.
Other good characteristics of rotational position detection device, the characteristic of the galvanometer scanner that especially same simulation servo-drive system is used together comprises that output voltage or electric current are the characteristic of linear relationship with respect to rotation angle.That is to say that the incremental change on axle rotates will produce equal incremental change aspect the output signal of position detector.Further, signal to noise ratio (S/N ratio) will be high as much as possible.
Exist several kinds of modes to come the position of inductive axis in optical scanner.The position detector of two general kinds comprises electric capacity position detector and optical position detector.
The electric capacity position detector is used in that some are very original in the galvanometric optical scanner.In a known detector, one rotates the dielectric butterfly plate is connected on the scanner axis, and check-out console is fixed.
Optical position detector has formed based on the selected position detector in the galvanometric optical scanning field recently.Usually, optical position detector can be processed very little, has low inertia, and can low-costly make.These characteristics make optical position detector conform with the needs of the optical scanner that adopts in commercial market and the consumer market.
A kind of optical position detector is " projection " position detector, wherein attempts to illuminate equably the big zone of optical sensor material, and through the light blocker shadow is incident upon on the optical sensor.Optical position detector can use photoelectric tube as optical sensor.These photoelectric tubes are the most general large tracts of land PIN type photodiodes, and are used for " photoelectricity " pattern, amplify through photoelectric tube generation electric current and through operational amplifier thus.When the linear increase of the light intensity on the overall optical fulgurite zone, the numerical linear of electric current increases.As long as the illumination on the whole zone is constant, the numerical value of electric current is linear increasing when the illuminating partial linear and increase of photoelectric tube also.That is to say, if bright half optical sensor of illumination zone, and light is stopped that in other half optical sensor zone the electric current of output will be the half the of the whole exposures of optical sensor, the linear relationship of output of formation position detector and photoelectric tube area illumination.
No matter the kind of use location detecting device is electric capacity or optics, all known position detectors all are considered to have a common problem: they all export the signal that the relative axle of expression rotates, but the signal that absolute axle rotates is not represented in output.That is to say, can not the read-out position signal voltage concerning servo controller or electric current and the accurate mechanical angle of knowing axle with absolute term.This is to be directly proportional with the signal that the light or the oscillator of LED generation produce respectively because of the output from photoelectric tube or capacitor board.Under the optical position detector situation, if increase owing to environmental change or element drift from the light of LED, the output that produces through photoelectric tube will increase pari passu.This relative growth will be cheated servo-drive system and believed that axle has turned to bigger mechanical angle.So this servo-drive system will manage to compensate and produce mistake.
All known position detectors are attempted to revise this problem through automatic gain control (AGC) circuit as known in the art.Under the situation of optical position detector, the light that all photoelectric tubes are received formation " total luminosity " signal voltage of adding up.This " total luminosity " voltage and reference voltage compare, and produce the rub-out signal of a driving LED.Increase if sense " total luminosity ", make light output deduct corresponding quantity so, thereby manage the susceptibility of holding position detecting device in time through LED.Yet, use AGC just to be enough to revise initial instruction issue.Because second-order effects; All known location detecting devices all have the offset drift variation of " absolute zero " aspect, position of axle (position detector think) to drift about (variation that position detector is represented with the mode of every degree voltage) variation of the feedback resistor that for example uses in the drift of reference voltage itself or the operation amplifier circuit with position scale.These variations and time and temperature exist simultaneously.
In the past, other signals of some absolute position of expression have been attempted to provide for rotational position detection device.With selection or automatic algorithms, servo-drive system can use the galvanometer scanner to seek other signals, thereby finds the absolute position scale and the offset of position detector.When being used in the electric capacity position detector, this technology has several accessory problems.The first, the electric capacity position detector is very sensitive to the shape of panel element.Because the edge effect outstanding or groove produces, the plate that has outstanding or groove will have affected linearity.If use other capacitor board, edge effect also can influence linearity.Whether and no matter should technology use with optical position detector or electric capacity position detector, the mobile butterfly plate of given shape manufactures expensive more.
The main servo-drive system that is used to control based on galvanometric optical scanner is the PID servo-drive system of being processed by analog element fully (analog servo system).Because relatively cheap and simple relatively, analog servo system is brought into use, and since up to now digital servosystem all can not obtain essential high resolving power and high sampling rate concerning using fast current meter scanner.For the fast current meter scanner of supporting that current market is sold, and in the working time of less than 100 microsecond scopes completing steps, must use the sampling rate of 200kHz and the sampling resolution of 16bits.And owing to need a plurality of internal calculation steps, Floating-point Computation caters to the need very much.Up to date, the servo controller of realizing having high sampling rate and resolution with digital form all is that cost is too high.Yet; Along with the inevitable steady progress that occurs in the technical field; Digital signal processor (DSPs) and analog-digital converter with enough speed and should cost become available at present, this will help to produce that power supply flowmeter scanner uses, from analog servo system to conversion based on the servo-drive system of DSP.
Analog servo system has pot a large amount of relatively, that be used for " adjusting " servo-drive system optimum performance usually.These pots are adjusted a large amount of servo parameters, comprise servo-drive system gain, damping, notch filter frequency, the notch filter degree of depth, input gain, input skew or the like.Usually also have two additional pots to adjust the position scale and the offset of position detector.Though latter two is said from the strict sense and is not servo parameter, their influence servo-drive system performance and precision really.All these pots must be manual adjustment or through people's " adjusting ".Usually this factory that is adjusted in carries out, but need further regulate at the scene sometimes.Because the slip-stick artist is not the system final user who has the galvanometer scanner, any non-factory regulates all possibly cause time good speed row.
To conversion will avoid the use of all these adjustment pots based on the servo-drive system of DSP, because the servo parameter of for example servo-drive system gain, damping, notch filter frequency or the like all will be set by the algorithm constant.These algorithm constants can through the people with carry out the identical mode of pot adjustment and carry out manually " adjustings ", only use user interface adjustment, perhaps replacedly, these algorithm constants can be regulated through some intelligent adjusting algorithms automatically.Collect because nearly all information of relevant scanning system only through utilization scanner and observation place signal what has taken place, this is possible.For example, the torque constant of scanner can obtain through the back electromotive force of observing scanner.Be expressed as KT=KE in the mechanical engineering.That is to say that every ampere dynes per centimeter torque is directly proportional with the back electromotive force of the every degree voltage of per second.Therefore, if servo-drive system causes scanner movements and can measure " degree/second " and the motor back electromotive force that this servo-drive system can obtain the accurate torque constant (KT) of scanner so.
In case KT is known; Next this servo-drive system can apply the current known pulse short time and measure the angular acceleration that produces; Because power equals quality and multiply by acceleration, thereby this servo-drive system can be collected the system inertia (J) of rotor, mirror and position detector.Therefore, inertia equals KT divided by acceleration.
Next, this servo-drive system will be placed the ring of light and make Bode diagram around scanner, therefore show the resonance of all systems.According to this information, servo-drive system can be set all pole and zero constants of notch biquadratic filter.
In case torque constant, system inertia and system resonance are all known, all servo parameters all mode that is accurate to second of available digital are set smoothly, obtain the absolute maximum performance from scanner and servo-drive system.But in order to make all these generations, this servo-drive system needs a basic information unit (BIU).This servo-drive system must be known " position scale ".That is to say that this servo-drive system must at first be known the every degree voltage from position detector.
As stated, for the position detector of previously known, servo-drive system can not be known the absolute position scale of confirming; Therefore can not form complete self-regulating digital servosystem.Up to now, scanner manufacturer the side addresses this problem in the scanner through little memory chip is put into.Digital servosystem can read this memory chip, and this memory chip comprises information and other information relevant with scanner of torque constant, position scale and offset in factory pre-programmed.The problem that adopts this method is that these parameters can change along with the time.The torque constant of scanner depends on the magnetic of rotor (or other scanner element), and this magnetic confirms ground with temperature variation, and if this scanner abuse or overheated also can change in time.Because element drifts about and owing to temperature and other environmental impacts, the position detector element also changes in time.
Therefore, useful providing a kind ofly has the rotational position detection device of improved signal to noise ratio (S/N ratio) and absolute positional accuracy is provided.
Summary of the invention
The present invention refers to a kind of optical position detector that low inertia operation is provided and can uses with the compact optical scanner.In addition, the present invention provides improved signal to noise ratio (S/N ratio) and absolute positional accuracy can optionally be provided.
At this a kind of rotational position detection device is provided, comprises the housing that has by the inner space of inner wall limit, on a part of inwall, have reflecting surface at least.Light source is set makes light inject the inner space of housing from housing bottom.Base is located in the enclosure interior space;
Optical detector components is arranged in the inner space of this housing and comprises the fan-shaped in the form of a ring basically optical sensor of first quantity, and this optical sensor is located on the base and is provided with in pairs around the axis of motor drive shaft.Each is to comprising " A " detector element and " B " detector element.Every pair all is arranged to make each " A " detecting device along circumferentially being arranged between two " B " detecting devices and each " B " detecting device is located between two " A " detecting devices.Term " optical sensor " is used for representing having substantially the zone of the photochromics of said shape at this; For example, can provide and " modification " difform optical sensor material provides said optical sensor.
The light blocker is fixed in the inner space of housing so that rotate with the motor drive shaft that is positioned at optical detector components and light source top.That this light blocker comprises is second quantity, that arrange around the axis of motor drive shaft, opaque, have the element that equates surface area substantially.Second quantity equals the half the of first quantity.Therefore the light that sends from light source, arrive reflecting surface reflects at optical detector components, and is stopped that by the light blocker light that can not arrive reflecting surface is not received by optical detector components.
Signal connector is located between a light detector elements and the circuit, and this circuit is used to measure and drops on relevant, the signal from " A " detecting device to " B " detecting device of wherein light quantity.Difference between " A " detector signal and " B " detector signal is relevant with the position, angle of motor drive shaft.
In conjunction with accompanying drawing, can understand the characteristic that characterizes structure of the present invention and method of operating better according to ensuing description, with and further purpose and advantage.Can be expressly understood that accompanying drawing is that from diagram and illustrative purposes and plan limits the invention.When combining the ensuing instructions of advantages, these and other purpose and the advantage provided by the invention that realize through the present invention will become more clear.
Description of drawings
Fig. 1 is the side perspective view of an embodiment of optical position detector of the present invention, illustrates housing with cut-open view.
Fig. 2 is the side perspective view of optical position detector among Fig. 1, illustrates the light path of light when not having the light blocker, illustrates housing with cut-open view once more.
Fig. 3 is the top/side perspective view of position transducer of the present invention, has removed housing and be illustrated as axle to rotate counterclockwise.
Fig. 4 is the top that comprises the position transducer and the light blocker of circuit board, optical sensor, illustrate external diameter than optical sensor little the light blocker of Duoing.
Fig. 5 A, 5B illustrate the top/side (Fig. 5 A) and bottom (Fig. 5 B) skeleton view of the alternative of cup-shaped light blocker.
Fig. 5 C, 5D illustrate the top/side (Fig. 5 C) and bottom (Fig. 5 D) skeleton view of the alternative of the light blocker with " carnival hat " shape.
Fig. 5 E illustrates the top/side perspective view of another embodiment of the light blocker with end face that a part cuts away.
Fig. 6 illustrates the embodiment that connects the optical sensor that is used to provide the output signal, and wherein the relative optical sensor of diametric(al) links to each other and two outputs only are provided.
Fig. 7 illustrates another embodiment that connects the optical sensor that is used to provide the output signal, and wherein the output of each optical sensor is directly used and is not connected with other optical sensors.
Fig. 8 has provided the top that concerns between light blocker element and the optical sensor.Dotted line representes that each optical sensor components is relative with the light blocker.
Fig. 9 is from " A " and " B " curve to the output signal of optical sensor and synthetic " A-B " output, wherein illustrate synthetic output and be linear up to " A " to or " B " optical sensor is exposed fully; After that, position detector still provides output, but is to provide with the rate of change that reduces.
Figure 10 is the side perspective view of another embodiment of optical position detector of the present invention, and it has the catoptron that is located at in the illustrated housing of cut-open view.
Figure 11 is the side perspective view of another embodiment of optical position detector of the present invention, and wherein the light blocker is that bottom by motor drive shaft forms, and illustrates housing with cut-open view.
Embodiment
Now will describe the present invention more up hill and dale according to Fig. 1-11 hereinafter, wherein show the preferred embodiments of the present invention.Only if qualification is arranged in addition, used here all science and technology and scientific terminology all have with the present invention under the identical implication of technical field those of ordinary skill common sense.Though with describe similar or equivalent method and material at this and be used for practical application or experiment of the present invention, suitable method and material are described below.Here all publications of mentioning, patented claim, patent or other list of references are all incorporated into by reference and all.Under the situation of contradiction, comprise that this instructions of any definition will be examined.In addition, the material that provides, method and embodiment only are exemplary in essence but not are intended to restriction.Therefore, the present invention can adopt the multitude of different ways performance and should not regard the illustrated embodiment that is restricted in this elaboration as.It would be better to, these illustrated embodiment are provided so that disclosure is thoroughly complete, and scope of the present invention is conveyed to those of ordinary skill in the art fully.According to ensuing detailed description, other characteristics of the present invention and advantage will become clear.
Optical position detector of the present invention is used " projection " technology.When comparing, improve each element of this position detector, obtain the improvement result of positional precision and signal to noise ratio (S/N ratio) aspect with other known optical position detector.In addition, some embodiment of this position detector allows to confirm that according to the position detector ability absolute position representes that it has arrived a certain horn shape attitude.
The preferred embodiments of the present invention can see in Fig. 1, and in it is used in the scope of motor or galvanometer scanner, describe, but do not plan as restriction.In the position detector of Fig. 1, light source 4 is located in the inner space 21 of housing 6.Housing 6 is suitable for accommodated position sensing system element and absorbs unwanted light from environment, and these elements is connected to the axle 10 of motor in a particular embodiment.Housing 6 comprises for example injection plastic or machine work metal, but this does not plan as restriction.
The light source 4 preferred uniform light field that produce generally along circumferential distribution are with the inwall 20 of light 5 guide housings 6.The inwall 20 of housing 6 comprises mirror reflection surface 11, and this reflecting surface points to a plurality of optical sensor 7A, 7B, 8A, 8B that for example comprise the annular sector element again with light 5. Optical sensor 7A, 7B, 8A, 8B can make on photodetector chip 7,8 and be installed on the base that comprises circuit board 2, and on a side identical with light source 4 of motor.
Light blocker 12 with a plurality of teats of pie basically 90 and 92 periodically stops the light 5 that arrives housing 6 inside surfaces, therefore also comes periodically to stop to arrive optical sensor 7A, 7B, 8A, some regional light of 8B through cast shadow above that.
According to Fig. 1 and 2 position transducer light source and inner shell are described now.Light source 4 preferably includes with photodetector chip 7 and 8 and is installed in the single LED on the same circuit board 2.Fig. 1 and 2 has shown with photodetector chip 7 and 8 and has been installed in the LED on the opposite side of circuit board, and has been directed to the through hole 3 in the circuit board 2 from the light of light source 4.This is desirable, because will end on circuit board 2 materials and can not directly impinge upon on photodetector chip 7 and 8 with arbitrary light of landscape mode emission.Yet as long as light source is suitable and setting between two parties substantially, other embodiment also are possible.For example, single led chip can be installed on the same side of circuit board with photodetector 7 and 8, even is directly installed on the photodetector matrix.
Light 5 penetrates the also inwall 20 of directive housing 6 along the direction away from photodetector chip 7 and 8 from light source 4.The inwall 20 of housing 6 comprises mirror reflection surface 11, and this reflecting surface reflects back into photodetector chip 7 and 8 with light 5.
Therefore this mirror reflection surface 11 can be bending as shown in the figure, for example becomes para-curve or elliptical shape, makes light more parallel and be that light is concentrated in the conventional zone of photodetector 7A, 7B, 8A, 8B.Yet this mirror reflection surface 11 also can show as other shapes, for example taper and even flat ring 61, as long as allow not 12 that stop by the light blocker, arrive photodetector 7A, 7B, 8A, 8B from the light 5 of light source 4.
In addition, Fig. 1 and 2 has shown the inwall 20 of the housing 6 with mirror reflection surface 11, but it is contemplated that, has an embodiment, adopts the individual component that is held in place through housing 6 that mirror reflection surface 11 is provided thus.
Though position detector light source 4 is described as LED, light source can also be expressed as phosphor dot or the edge needs direction to produce any other source of suitable light cone.Should be understood that the position detector light source can be that optical fiber is supplied with.That is to say that actual light source can be provided with at a distance, for example be located on the servo-drive system drive plate and utilize optical fiber to supply to the galvanometer scanner.This possibly be used in the military applications, and in this is used, scanner will at high temperature be worked, and this is that direct LED operation is forbidden.In addition, when supplying with through optical fiber, can be with laser with the light-emitting device that acts on light source.
The embodiment of optical detector components and light blocker for example is discussed according to Fig. 3 and 4 now, and its location is as shown in Figure 1.Optical detector components is positioned at the inner space 21 of housing 6.In the exemplary detectors assembly of Fig. 3 and 4; Optical sensor comprises first quantity (being 4 here) optical sensor 7A, 7B, 8A, 8B fan-shaped in the form of a ring basically, that have the surface area that equates basically; These optical sensors are arranged in pairs on the photodetector chip 7,8 around the light source 4, and are installed on the circuit board 2.Each is to all comprising " A " detector element 7A, 8A and " B " detector element 7B, 8B.Every pair all is arranged to make each " A " detecting device 7A, 8A along circumferentially being arranged between two " B " detecting device 7B, the 8B and each " B " detecting device 7B, 8B are located between two " A " detecting device 7A, the 8A.
The structure of this sensor construction major decision light blocker 12 and blade 90,92 thereof.Light blocker 12 comprises that second quantity (being 2 here) is arranged in the axis 10 opaque element 90,92, that have the surface area that equates basically of motor drive shaft on every side.Should be understood that second quantity (for example 2) equals the half the of first quantity (for example 4).
With reference to figure 8; Wherein the light blocker exposes " B " fully to optical sensor; And it is right not cover " A " fully, and the angle of chord of each open area of light blocker (be here 60 degree) can ratio sensor element 7A, the different angle of chord (being 5 degree here) of the angle of chord (being 55 degree here) of 7B, 8A, 8B.Because this, the CW that further increases rotates not and can cause any increment to the output side signal face of optical sensor at " B ", but at " A " the output side signal face is caused a large amount of minimizings.When the angle of chord of light blocker opening during greater than the angle of chord of light detector elements 7A, 7B, 8A, 8B; Sensor changes the angle that is no more than light detector elements 7A, 7B, 8A, the 8B angle of chord provides linear output, and the angle that surpasses this point is changed provides non-linear output then.
The radially elongation of each light blocker element 90,92 can be less than the radially elongation of light detector elements 7A, 7B, 8A, 8B, and is not more than the radially elongation of the inner edge 71 of light detector elements 7A, 7B, 8A, 8B.In some cases, depend on the elongation of the reflecting part 11 of the cone angle that comprises light source 4 and inwall 20, the radially elongation of light blocker element 90,92 can be obviously littler.This is favourable when comparing with the sensor of prior art, and the radially elongation of light blocker must be greater than the radially elongation of the external diameter of photodetector 7A, 7B, 8A, 8B in the prior art.Less radially elongation has reduced inertia in essence, thereby improves system performance simultaneously.
When 85 rotate (shifting to structure shown in Figure 3 from structure shown in Figure 1), illuminated by light source 4 by most of " A " optical sensor zone on axle 10 edges " just " for light blocker 12 configurable one-tenth, and most of " B " optical sensor zone is under the shade.Therefore, when light blocker 12 rotates,, can in fact stop fully before light arrives " B " optical sensor 7B, 8B and further rotate at it in case expose " A " optical sensor 7A, 8A fully.This accurately detects servo-drive system when " A " and " B " sensor is covered fully, thereby with the exterior angle of the accurate detection position of absolute term sensor.Yet some is used does not need this absolute position to confirm, and can use its opening to have the light blocker with sensor element 7A, 7B, 8A, the angle of chord that 8B is identical.
Though accompanying drawing has shown four photodetector 7A, 7B, 8A, 8B and has had the light blocker of two outstanding elements 90,92; Should be appreciated that; Few to four photodetectors and two light blocker teats; Perhaps much eight photodetectors of as many as and four light blocker teats more all are possible perhaps, and still fall within the scope of the invention.
Discrete optical sensor can comprise optical sensor material or the device of operating on principle, and the linearity increase of per unit area glazing makes and in the output signal, produces linear increasing thus.As non-limiting example, silicon photoelectric diode, PIN type photodiode, avalanche photodide and cadmium sulphide cell can be used as the optical sensor among the present invention.These are commonly referred to as " photoelectric cell ".
Be known that that discrete optical sensor is set on single " photoelectric cell " matrix of rectangle is right being depicted as like Fig. 1-4.Yet discrete optical sensor can be assembled by any way, as long as meet above-mentioned linearity and shape limits is just passable.Further, optical sensor can have the area bigger than diagram, for example can comprise the chip of arbitrary shape respectively, and be provided with decoration element above that, hopes the fan-shaped of use to form.
This light blocker is designed to prevent that the light that is given out by light source 4 from arriving on the each several part of the specular reflection film 11 on the inner walls 20, thereby prevents that light from arriving the each several part of optical sensor 7A, 7B, 8A, 8B.The light blocker 12 that comprises pie blade 90,92 utilizes epoxy resin or other attachment arrangements to be operably connected on the rotation axis 10.
Because the light blocker only need prevent light and arrive optical sensor, so it can be processed by various materials.For example, can process by pottery, spun glass/epoxy resin, sheet metal, glass, plastics or any suitable material of light that can stop.Can use conventional manufacturing process to make the light blocker, such as injection moulding, cut, punching press, photoengraving or standard process for machining.
The light blocker is made into consistent with the shape shown in Fig. 1-4, is perhaps processed by transparent plate, realizes barrier functionality through the opaque material that is deposited on the transparent plate thus.In addition, other embodiment also is possible.Fig. 5 A, 5B have shown the alternative of light blocker 30, and wherein cup-shaped light blocker is formed with axial teat.That is to say that the end face 31 of light blocker 30 has two and is arranged in central disc 33 element that is pie basically 32 on every side.What hang down from end face 31 is the sidewall 34 that forms the part cylinder, and this cylinder has the outward flange 36 equal top 35 of extending with end face 31.
Fig. 5 C, 5D have shown that interior section has another embodiment with the light blocker 40 of above-mentioned smooth blocker 30 similar shapes.Yet at this, two base member 41 stretch out from sidewall 42, form a pair of annular sector flange, and the inner edge 43 of this flange combines sidewall 42 at its bottom margin 44 places.Therefore this light blocker 40 has a kind of " carnival hat " shape.
Fig. 5 E illustrates the another embodiment of light blocker 50, comprises cylindrical circular basically element, has the inner space 57 that is limited sidewall 54 and is set to receive the light from light source 4.In a particular embodiment this circle tube element have through its end face 51 and along central disc 53 diametrically opposed, have an a pair of opening opposing 52 of equal areas basically.Opening 52 is used to allow light to pass arrival reflecting surface 11.
In another embodiment (Figure 11), light blocker 70 comprises the bottom 71 of motor drive shaft 10.The bottom comprises that one is roughly columnar part, has to be set to receive the inner space 72 from the light of light source 4.This cylindrical shape part 71 has two openings 73 relative, same size or " window ", for example in this embodiment, begin to extend through from its bottom margin 74, but this does not constitute restriction.Opening 73 limits the parts of the cylindrical shape part 71 that can be used as light blocker element.In addition, wording " a pair of " does not plan can comprise as many as 8 and even more as restriction in some number of applications.Each opening 73 all has is enough to allow light to pass through the height 75 that it arrives reflecting surface 11.
Should believe that aforesaid smooth blocker 30,40,50,70 can improve the shade that is incident upon on the photodetector, if if particularly light source is not that the quality of pointolite and/or mirror reflection surface is when reluctantly qualified or very poor.
Should be understood that it is not strict essential that alternative light blocker embodiment has rectangular characteristic.This cup can be made conical part, can realize more easily making light blocker or better photoresistance property.In addition, thus light blocker itself can show as blade and even directly on motor drive shaft itself, carry out the keyway that machine work realizes hindering the light function.
Different with the rotational position sensor of previously known, the opening of light blocker can have the angle of chord bigger than the optical sensor of separation.When accomplishing this, there are several advantages.An advantage is, because the angle of chord of light blocker opening is greater than the angle of chord of optical sensor, when rotating along " forward " direction 85, " A " optical sensor did not stop before " B " optical sensor is stopped fully fully.Further " forward " rotates and still produces the detected output from " B " sensor, but can not produce the output from " A " sensor.Therefore output further changes and another this state that does not further change can be used to confirm shaft angle exactly with absolute term.Another advantage is; If A and B output are subtracted each other; As the exemplary process that is used for this sensor, existence and " linearity " part of exporting the corresponding axle of signal rotation angle, and locate on the edge of to exist and " non-linear " part of exporting the corresponding shaft angle of signal.For example, in Fig. 9, the rate of change of output is expressed as and surpasses 25 degree variations.
Preferably, generally speaking, light blocker opening has the same with the optical sensor angle of chord at least big angle of chord.Yet, one with ordinary skill in the art would appreciate that the angle of chord can be basic identical with the angle of chord of optical sensor under the situation that does not deviate from spirit of the present invention, in addition littler.In certain embodiments, the angle of chord of light blocker opening can be made into the arbitrary desirable numerical value that can satisfy the requirement of engineering of system than the angle of chord of optical sensor greatly.Yet, to use for optical scanning, it usually can be in 2-10 degree scope.
The number of light blocker opening includes as few as 2 as many as 8 or more, as long as each light blocker opening has 2 optical sensors (" A " and " B "), a large amount of light blocker openings have reduced the operation angle of position detector.The maximum angular (calculating with degree) that position detector can be exported single ramp signal from " master " output area equals 360 and deducts (the blade angle of chord deducts the optical sensor angle of chord) divided by lobe numbers.
When the light blocker when complete light-absorbing material is processed basically, do not allow light through arriving mirror reflection surface and detecting device.Embodiment hereto, light blocker comprise black plastic, black oxidation metal or are deposited on the black coating on transparent plate or the transparent tube.This shows that all light that send from light source arrive photodetector then or absorbed by the each several part of light blocker from the mirror face reflection coating reflection.
Have teat though should be pointed out that light blocker described here simultaneously, those of ordinary skills should admit that they can not have teat that the zone of being in the light is arranged.For example, the light blocker can comprise and has the transparent plate that is imprinted on top barrier zones or other light pipes.
In alternate embodiment 63 (Figure 10), reflecting surface can comprise: be arranged at least a portion of bottom surface 62 of annular reflex element 61 of the inner space 21 of housing, thereby allow the hole 64 of motor drive shaft 10 through rotating betwixt.In this embodiment 63, reflecting element 61 fix in position are on the inner walls 20 of light blocker 12 tops.As for the embodiment among Fig. 11, the light 5 that is not stopped by light blocker 12 arrives the reflection bottom face 62 of reflecting elements 61 and reflexes to optical sensor 7A, 7B, 8A, 8B last.
Pass the signal that rotational position detection device of the present invention produces now through discussion.In one embodiment, discrete optical sensor is connected in parallel, and therefore minimum electric wire is sent to servo controller, and is as shown in Figure 6.The benefit of this connected mode has been to reduce link position detecting device and the required number of wires of servo-drive system.Yet; The defective common with position transducer in the prior art is; If the optical sensor for given light quantity, the separation that is connected in parallel just produces the output semaphore the same with other discrete optical sensors, so to not being best radially with the insensitivity of axially-movable.
As alternative connected mode, can be used one by one from the output of discrete optical sensor, as shown in Figure 7.The advantage of this layout is that this servo-drive system can characterize the output from each optical sensor, and pressing algorithm then increases insensitivity linear and radially.In this embodiment, forming output through the pad on the circuit board 29 connects.
Position detector of the present invention is particularly useful when being connected to digital servosystem; This digital servosystem can use this scanner and will put successfully to be arranged in the rotation that " A " and " B " optical sensor stopped fully, thereby confirms the angle degree of drifting about with absolute term.Thus, do not need the AGC system, and light source carries out work with maximum output all the time, thereby make signal to noise ratio (S/N ratio) maximum.
In drawing and description, representative preferred embodiment of the present invention is disclosed, though adopted proprietary term, the term of use only is a describing significance rather than in order to limit.Specifically described very much the present invention in detail with reference to these illustrated embodiment.Yet it is obvious that can carry out various distortion and variation in essence of the present invention that above-mentioned instructions is described and scope.
Claims (25)
1. rotational position detection device, this rotational position detection device comprises:
Housing has by the inner space of inner wall limit and has the hole of top to allow motor drive shaft to pass that is positioned at said housing;
Base is located in the inner space of said housing;
Light source is set to make light upwards to inject the inner space of said housing from the bottom of contiguous said housing;
Optical detector components; Be arranged in the inner space of said housing; And comprise optical sensor fan-shaped in the form of a ring basically, first quantity; These optical sensors are arranged on the said base and around the axis and the light source of said motor drive shaft and arrange in pairs; Each comprises " A " detector element and " B " detector element to optical sensor, and the optical sensor of arranging in pairs is arranged to make each " A " detecting device edge circumferentially to be arranged between two " B " detecting devices and each " B " detecting device is arranged between two " A " detecting devices;
The light blocker; Be arranged in the inner space of said housing; And can rotate with the said motor drive shaft that is positioned at said optical detector components and said light source top, that said smooth blocker comprises is second quantity, that arrange around the axis of said motor drive shaft, have the surface area, the opaque element that equate basically, said second quantity equals the half the of said first quantity; Wherein, the radially elongation of each element of said smooth blocker is basically less than the radially elongation of said optical sensor;
Reflecting surface; Be arranged in the inner space of the said housing of said smooth blocker top; Wherein, The light that sends from light source, arrive said reflecting surface is made that by reflection downwards some light in the light arrive said optical detector components, and is stopped and the light that can not arrive said reflecting surface is not received by said optical detector components by said smooth blocker; And
Signal connector; Be positioned at said light detector elements and be used for measuring between the circuit from said " A " detecting device and said " B " signal detecting device, relevant with the light quantity on shining it, from the signal of " A " detecting device and relevant with the position, angle of said motor drive shaft from the difference between the signal of " B " detecting device.
2. rotational position detection device according to claim 1 is characterized in that, the radially elongation of each element of said smooth blocker is not more than the radially elongation of the inner edge of said optical sensor.
3. rotational position detection device according to claim 1; It is characterized in that; Said smooth blocker has a plurality of openings; Each opening between the adjacent elements of said smooth blocker, and the angle of chord of each opening in a plurality of openings of wherein said smooth blocker the angle of chord with said optical sensor is the same big at least.
4. rotational position detection device according to claim 1 is characterized in that, said light source comprises basically the single light source with the axis alignment of said motor drive shaft.
5. rotational position detection device according to claim 1 is characterized in that, the optical sensor of said first quantity comprises four optical sensors.
6. rotational position detection device according to claim 1; It is characterized in that; Said optical sensor comprises photosensitive optical sensor material, and wherein, the linearity that is radiated at the per unit area glazing on the said optical sensor increases makes output signal substantial linear increase.
7. rotational position detection device according to claim 1 is characterized in that, each element of said smooth blocker comprises blade.
8. rotational position detection device according to claim 1 is characterized in that said smooth blocker comprises the dish of substantial transparent, and said opaque element has been applied on this dish.
9. rotational position detection device according to claim 1 is characterized in that said reflecting surface comprises the part of the inwall of said housing.
10. rotational position detection device according to claim 1; It is characterized in that; Said reflecting surface comprises the element of the inner space that is arranged in said housing; This element has the bottom surface, and at least a portion of said bottom surface is reflective, and this element also has and is enough to the hole that allows said motor drive shaft to pass.
11. rotational position detection device according to claim 1 is characterized in that, each element in each element of said smooth blocker also comprises the sidewall that is dangled by this element downwards, thereby forms cup-shaped basically light blocker.
12. rotational position detection device according to claim 11 is characterized in that, each element in each element of said smooth blocker also comprises from the outward extending annular sector flange of the bottom margin of said sidewall.
13. rotational position detection device according to claim 1; It is characterized in that; Said smooth blocker comprises cylindrical circular basically element; This cylindrical element has sidewall and limits and be set to receive the inner space from the light of said light source, this circle tube element have a pair of space, basically have equal areas, through the opening of its end face, arrive said reflecting surface to allow light to pass.
14. rotational position detection device according to claim 13 is characterized in that, the angle of chord of the said opening angle of chord with said optical sensor at least is the same big.
15. rotational position detection device according to claim 1; It is characterized in that; Said smooth blocker comprises the bottom of said motor drive shaft, and this bottom comprises the cylindrical circular basically part with inner space, and this inner space is set to receive the light from light source; Each element of said smooth blocker comprises the parts through the cylindrical shape part of separating from its bottom margin opening that extend, the space, and this opening has is enough to allow light to pass the height that arrives said reflecting surface.
16. rotational position detection device according to claim 15 is characterized in that, the angle of chord of the said opening angle of chord with said optical sensor at least is the same big.
17. a method that detects the turned position of motor drive shaft, this method comprises:
Light is upwards shone in the inner space of housing, and this housing has the hole that is positioned at its top, passes to allow said motor drive shaft;
Reflect at least some light downwards;
Utilize optical detector components to detect at least some reflected light; This optical detector components is arranged in the inner space of said housing and comprises optical sensor fan-shaped in the form of a ring basically, first quantity; These optical sensors are arranged on the base and are provided with in pairs around the axis of said motor drive shaft; Each comprises " A " detector element and " B " detector element to optical sensor, and the optical sensor that is provided with in pairs is arranged such that each " A " detecting device edge circumferentially is arranged between two " B " detecting devices and each " B " detecting device is arranged between two " A " detecting devices;
Utilization is arranged in the inner space of said housing, the light blocker that rotates with said motor drive shaft stops the upwards light of irradiation of a part; That said smooth blocker comprises is second quantity, that arrange around the axis of said motor drive shaft, have the opaque element of equal surface area basically; Said second quantity equals the half the of said first quantity; The light that stopped thus part can not arrive said optical sensor, and wherein the radially elongation of each element is basically less than the radially elongation of said optical sensor; And
Receive and handle from " A " detecting device and " B " detecting device, relevant signal, from the signal of " A " detecting device and relevant with the position, angle of said motor drive shaft from the difference between the signal of " B " detecting device with the light quantity on shining it.
18. method according to claim 17 is characterized in that, the radially elongation of each element of said smooth blocker is not more than the radially elongation of the inner edge of said optical sensor.
19. method according to claim 17 is characterized in that, said irradiating step comprise by basically with the single light source irradiates light of the axis alignment of said motor drive shaft.
20. method according to claim 17 is characterized in that, the optical sensor of said first quantity comprises four optical sensors.
21. method according to claim 17 is characterized in that, said optical sensor comprises photosensitive optical sensor material, and wherein, the linearity that is radiated at the per unit area glazing on the said optical sensor increases makes output signal substantial linear increase.
22. method according to claim 17 is characterized in that, each element of said smooth blocker comprises blade.
23. method according to claim 17 is characterized in that, said smooth blocker comprises the dish of substantial transparent, and said opaque element has been applied on this dish.
24. method according to claim 17 is characterized in that, said reflection steps comprises said at least some light of reflecting part reflection by the inwall of said housing.
25. method according to claim 17; It is characterized in that; Said reflection steps comprises by said at least some light of the element reflects of the inner space that is arranged in said housing; This element has the bottom surface, and at least a portion of this bottom surface is reflective, and this element also has and is enough to the hole that allows said motor drive shaft to pass.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105547141A (en) * | 2014-10-27 | 2016-05-04 | 精工爱普生株式会社 | Position detecting device, electronic apparatus, recording apparatus, robot, and position detecting method |
| CN104121869B (en) * | 2013-04-27 | 2018-11-23 | 小威廉·R·本纳 | Rotational position detection device and correlation technique |
| CN111948804A (en) * | 2019-05-16 | 2020-11-17 | 船井电机株式会社 | Optical scanning unit and optical apparatus |
| EP2953571B1 (en) * | 2013-02-05 | 2021-04-14 | Convergent Dental, Inc. | Dental laser apparatus and method of use with interchangeable hand piece and variable foot pedal |
| CN114739325A (en) * | 2022-03-17 | 2022-07-12 | 安徽理工大学 | Device and method for measuring center deviation of rotor of stepping motor |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4959996A (en) * | 1988-09-27 | 1990-10-02 | Mitsubishi Denki Kabushiki Kaisha | Control signal generator for an internal combustion engine |
| JPH08313221A (en) * | 1995-05-16 | 1996-11-29 | Mitsubishi Heavy Ind Ltd | Equipment for picking up continuous image of rotating body |
| CN101482397A (en) * | 2008-01-11 | 2009-07-15 | 松下电器产业株式会社 | Shape testing method |
| US7688432B1 (en) * | 2007-01-23 | 2010-03-30 | Benner Jr William R | Rotary position detector and associated methods |
-
2011
- 2011-03-18 CN CN201110066043.6A patent/CN102679910B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4959996A (en) * | 1988-09-27 | 1990-10-02 | Mitsubishi Denki Kabushiki Kaisha | Control signal generator for an internal combustion engine |
| JPH08313221A (en) * | 1995-05-16 | 1996-11-29 | Mitsubishi Heavy Ind Ltd | Equipment for picking up continuous image of rotating body |
| US7688432B1 (en) * | 2007-01-23 | 2010-03-30 | Benner Jr William R | Rotary position detector and associated methods |
| CN101482397A (en) * | 2008-01-11 | 2009-07-15 | 松下电器产业株式会社 | Shape testing method |
Non-Patent Citations (1)
| Title |
|---|
| 王群京等: "三维球形电动机位置检测的研究与发展", 《微特电机》 * |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP2953571B1 (en) * | 2013-02-05 | 2021-04-14 | Convergent Dental, Inc. | Dental laser apparatus and method of use with interchangeable hand piece and variable foot pedal |
| CN104121869B (en) * | 2013-04-27 | 2018-11-23 | 小威廉·R·本纳 | Rotational position detection device and correlation technique |
| CN105547141A (en) * | 2014-10-27 | 2016-05-04 | 精工爱普生株式会社 | Position detecting device, electronic apparatus, recording apparatus, robot, and position detecting method |
| CN111948804A (en) * | 2019-05-16 | 2020-11-17 | 船井电机株式会社 | Optical scanning unit and optical apparatus |
| CN111948804B (en) * | 2019-05-16 | 2022-04-15 | 船井电机株式会社 | Optical scanning unit and optical apparatus |
| US11366308B2 (en) | 2019-05-16 | 2022-06-21 | Funai Electric Co., Ltd. | Optical scanner unit and optical device |
| CN114739325A (en) * | 2022-03-17 | 2022-07-12 | 安徽理工大学 | Device and method for measuring center deviation of rotor of stepping motor |
| CN114739325B (en) * | 2022-03-17 | 2024-03-29 | 张剑辉 | Device and method for measuring center deviation of rotor of stepping motor |
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