EP2089183A1 - Machine industrielle dotée de moyens de mesure interférométrique - Google Patents

Machine industrielle dotée de moyens de mesure interférométrique

Info

Publication number
EP2089183A1
EP2089183A1 EP06821769A EP06821769A EP2089183A1 EP 2089183 A1 EP2089183 A1 EP 2089183A1 EP 06821769 A EP06821769 A EP 06821769A EP 06821769 A EP06821769 A EP 06821769A EP 2089183 A1 EP2089183 A1 EP 2089183A1
Authority
EP
European Patent Office
Prior art keywords
industrial machine
machine
structural element
measuring
target
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06821769A
Other languages
German (de)
English (en)
Inventor
Costantino Florio
Francesco Mezzapesa
Basilio Vescio
Gianpiero Negri
Gianluca Guadagno
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sintesi ScpA
Original Assignee
Sintesi ScpA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Sintesi ScpA filed Critical Sintesi ScpA
Publication of EP2089183A1 publication Critical patent/EP2089183A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
    • B23Q17/22—Arrangements for observing, indicating or measuring on machine tools for indicating or measuring existing or desired position of tool or work
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23Q—DETAILS, COMPONENTS, OR ACCESSORIES FOR MACHINE TOOLS, e.g. ARRANGEMENTS FOR COPYING OR CONTROLLING; MACHINE TOOLS IN GENERAL CHARACTERISED BY THE CONSTRUCTION OF PARTICULAR DETAILS OR COMPONENTS; COMBINATIONS OR ASSOCIATIONS OF METAL-WORKING MACHINES, NOT DIRECTED TO A PARTICULAR RESULT
    • B23Q17/00—Arrangements for observing, indicating or measuring on machine tools
    • B23Q17/24—Arrangements for observing, indicating or measuring on machine tools using optics or electromagnetic waves
    • B23Q17/248—Arrangements for observing, indicating or measuring on machine tools using optics or electromagnetic waves using special electromagnetic means or methods
    • B23Q17/2495—Arrangements for observing, indicating or measuring on machine tools using optics or electromagnetic waves using special electromagnetic means or methods using interferometers

Definitions

  • the present invention relates to an industrial machine, and particularly, an industrial machine provided with optoelectronic measure means.
  • industrial machine is meant a mechanic machine tool (such as a lathe, a grinding machine, a milling machine, or a drilling, boring machine) , and an electronic machine tool (such as a laser machining machine, electric spark machining machine), a pressure waterjet machine, a Coordinate Measuring Machine
  • CMM moving or manipulation machine
  • assembly machine a moving or manipulation machine
  • piece is meant both a piece of machinable material that cab be worked such as, for example, wood metal or plastics, that can be fixed to an industrial machine for machining, and a wall or large portion of solid material that cannot be mounted on an industrial machine, but that can be however reached and worked by means of an industrial machine, or generally any piece that can be handled and manipulated by an industrial machine .
  • machining is meant each of those operations that an industrial machine can carry out on a workpiece, such as, for example, removal of materials, milling, bending, polishing, and the like, and the surface treatment of the workpiece (such as, varnishing) , and other possible operations on a workpiece, such as measuring, manipulation, moving, or assembly.
  • operation of an industrial machine is further meant any of the functions that the machine can carry out, among which, for example, moving a tool within the operating area, holding the tool in any position, machining a workpiece, as well as adjustment, measuring or monitoring operations that can be carried out not only on the workpiece, but also on other mechanical or structural parts belonging to the industrial machine.
  • the workpiece is required to be accurately positioned on the machine, and the tool intended for machining the piece and the other mechanical parts that may be involved in the machining are required to move the same in the most precise manner as possible.
  • an industrial machine of this type upon operation, is subjected to stress or vibrations that may be caused, for example, by the interaction of the tool with the material to be worked, or by the handling, often at high speed, of a worktable on which the workpiece is fixed or still by the movement of the tool or other mechanical parts involved in the machining.
  • geometric deformations can occur in an industrial machine, both of permanent type, e.g. caused by an erroneous assembly or construction of the mechanical parts composing the same, and almost static type, e.g. caused by thermal variations or weight of the parts composing the machine. Accordingly, the need is deeply felt of having an industrial machine capable of providing an operator or control unit with the measure of displacements or dimensional variations to which the machine can be subjected upon operation in order to identify, in real time, machining errors by the industrial machine and increasing the precision of the latter by applying correcting measures. Furthermore, malfunctioning can be limited, while reducing the risk of mechanical failure.
  • An industrial machine typically consists of stationary mechanical parts and one or more axes, either linear or rotating, which are connected to each other.
  • axis is meant the assembly formed by two elements, typically the one stationary and the other movable relative to the first one, which are connected to each other such as to be capable of imparting a relative motion to each other via suitable movement transmission means. More particularly, by “linear” axis is meant an assembly of two elements with a relative motion of linear type being imparted therebetween, whereas by “rotary” axis is meant the assembly of two elements with a relative motion of rotary type being imparted therebetween.
  • the moving element In the linear axis, the moving element is slidably moved on the fixed element.
  • the moving element is moved, for example, by means of a rotary electric motor and a suitable mechanical transmission system (or alternatively, directly by a linear electric motor) .
  • the displacement of the moving element relative to the stationary element is typically indirectly measured by means of an angular measuring system, which is known in the literature with the technical name of "resolver” or angular encoder integral with the rotary motor.
  • the measurement can be directly obtained by means of a linear measuring system, known with the technical name of linear encoder, which typically consists of a graduated scale, typically an optical line, integral with the stationary element and of a reading head integral with the moving element.
  • the measure of the displacement can be further carried out using both measuring systems. More generally, industrial machines consist of one or more linear axes and/or one or more rotary axes.
  • a first industrial machine Ml of a known type is schematically shown in Fig. 1, which consists of a linear axis AL and is provided with a rotary motor MR, respective mechanical transmission means MTM, a linear encoder EL 7 a rotary encoder ER and a control unit UC.
  • This control unit is associated with the first industrial machine Ml such as to provide a respective command signal to the rotary motor MR based on the information generated by the linear encoder EL and rotary encoder ER.
  • the first industrial machine Ml in Fig. 1 (having only one linear axis) works, by means of a work tool (not shown in the figure) , a piece that can be fixed to the moving element of the linear axis or stationary element of the axis or a part of the machine, either stationary or moving.
  • the work tool can be either fixed to the moving element of the linear axis, or to the stationary element of the axis, or to a part of the machine, either stationary or moving.
  • FIG. 2 A portion of a second prior art industrial machine M2 consisting of more linear axes (ALl, AL2, AL3) is schematically shown in Fig. 2.
  • Fig. 2 for clarity purposes, motors, mechanical transmission means, measuring systems and control units are not shown.
  • an industrial machine with more linear axes and one ore more rotary axes consists of, for example, axes that are arranged sequentially relative to each other, i.e. with the stationary element of an axis being fixed to the moving element of the adjacent axis.
  • An industrial machine having more axes works, by means of a work tool, a piece that can be fixed to the moving element of one of the axes or to the stationary element of one of the axes or on a stationary part of the machine.
  • the tool can be fixed to the moving element of one of the axes or to the stationary element of one of the axes or to a part of the machine, either stationary or moving.
  • the control units of the individual axes can be either comprised or replaced by an individual control unit of the machine.
  • a prior art industrial machine typically consists of a base 1, acting as the stationary element of a linear axis, and a worktable 2 acting as the moving element of the linear axis, sliding on said base along a moving axis X (depicted in the figures with a dotted line) with a workpiece 4 made of solid material being fixed thereto.
  • the industrial machine 100 is also provided with a mechanical work tool 5 (shown in Fig. 3) for machining the piece 4 of material.
  • the movement of the moving worktable 2 relative to the base 1 is ensured by a conventional electric motor (not shown in the figures) which is conveniently mounted to the worktable or base, and by suitable means for the mechanical transmission of the relative motion between the worktable and base.
  • the industrial machine 100 is equipped with a linear encoder 6 consisting of a reading head 7, integral with the worktable 2, such as to be sliding, without mechanical contact, relative to an optical line 8 integral with the base 1.
  • the optical line 8 is arranged in a suitable space formed on the side of the base (stationary element of the linear axis) and results parallel to the moving axis X of the industrial machine .
  • the linear encoder 6 allows the industrial machine 100 to provide an operator, or control unit, with a measure representing the displacement of the moving table along the axis of movement of the industrial machine.
  • the prior art industrial machine 100 has the drawbacks that the quality and precision of the measure as provided by the linear encoder 6 critically depend on the geometry of the base on which the optical line is mounted. As the latter is, in fact, firmly anchored to the moving axis of the machine, it is affected by the deformation to which the base 1 is subjected upon operation. Any deformation of the optical line 8 affects the reliability of the measures being provided by the linear encoder and also the proper operation of the latter.
  • Another disadvantage of the industrial machine 100 as described above is the ⁇ sometimes considerable) distance between the linear encoder 6, the position of which depends on the position of the optical line 8 along the base 1, and the area of greatest interest for the measuring, usually the point in the axis of movement where the workpiece is fixed.
  • the object of the present invention is to provide an industrial machine that overcomes the drawbacks and has a more reliable operation than the prior-art industrial machine mentioned above.
  • the object of the present invention is achieved by means of an industrial machine such as defined and characterized in claim 1.
  • Preferred embodiments of said industrial machine are as defined by the annexed dependent claims 2 to 31.
  • FIG. 1 schematically shows a perspective view of a first prior-art industrial machine
  • Fig. 2 schematically shows a perspective view of a portion of a second prior-art industrial machine
  • FIG. 3 schematically shows a perspective view of a third prior-art industrial machine
  • Fig. 4 shows a side view of the third prior-art industrial machine in Fig. 3 ;
  • Fig. 5 schematically shows a perspective view of an industrial machine according to an example of the invention
  • Fig. 6 schematically shows an optoelectronic measuring device to be used with the industrial machine in Fig. 5;
  • Fig. 7 schematically shows a side view of the industrial machine in Fig. 3 in which a protection shield against electromagnetic radiation that can be generated by the optoelectronic measuring means in Fig. 6;
  • Fig. 8 schematically shows a variant embodiment of the protection shield as shown in Fig. 7.
  • operation of an industrial machine is further meant any function that the machine can carry out, among which, for example, moving a tool within the operating area, holding the tool in any position, machining a workpiece and also adjustment, measuring or monitoring operations that can be carried out not only on the workpiece, but also on other mechanical or structural parts belonging to the industrial machine.
  • machining is further meant each of those operations that an industrial machine can carry out on a piece, such as removal of materials, bending, polishing and the like, as well as surface treatment on the piece, such as varnishing.
  • the industrial machine 200 for example a milling machine comprises a base 1 or fixed element of a linear axis (only referred to the "base") and a moving structural element 2 on which a workpiece 4 is mechanically connectable using suitable fixing means such as adjustable jaws (not shown in the figure) .
  • the piece 4 can be either mechanically directly connectable to the base 1 or be physically placed outside the industrial machine 200.
  • the industrial machine 200 further comprises a mechanical tool 50 for machining the piece 4, for example a mill mounted to a chuck, the latter being preferably connected to the base 1 in a mechanical manner.
  • the mechanical tool 50 can be integral with the moving structural element 2; in other cases, it can be external to industrial machine 200 though however coordinated to and cooperating with the latter for machining the piece.
  • Other types of tools to be used as machining means alternative to that described above are, for example a grinder, a borer, a welding gun, or a laser head, or a varnishing head and however depend, more generally, on the type of industrial machine being used.
  • the type of workpiece 4 also depends on the type of industrial machine and machining desired. In the case of a stock removing machine tool, the piece is reasonably made of solid material, typically metal, wood or plastics.
  • the structural element 2 results to be slidingly coupled to the base 1 according to an axis of movement X (in the example, longitudinal to the base 1) of the industrial machine.
  • the moving structural element 2 is preferably provided with suitable grooves 9 facing the base 1 to be snugly engaged within respective ribs 10 that are formed on the base.
  • the sliding coupling described above allows the moving structural element 2 to be capable of adopting, relative to base 1, different positions representing corresponding operating configurations of the industrial machine 200.
  • the sliding coupling described above allows a plurality of mutual positions between the machining mechanical tool 50 (or generally other machining means) and the workpiece 4.
  • the movement of the moving element 2 relative to the stationary element 1 is ensured by a conventional rotary electric motor fixed to the moving structural element 2 (not shown in the figures) and respective mechanical transmission elements (also not shown in the figures) of the relative motion between the moving structural element 2 and base 1.
  • the rotary electric motor can be fixed to the base 1.
  • other moving means can be provided for the moving structural element 2, among which, for example, a linear electric motor, a pneumatic actuation system or a piezoelectric actuation system.
  • the industrial machine 200 further comprises an optoelectronic measuring device 11 that is arranged, for example, on the base 1 proximate to one of the two ribs 10 and a measuring reflecting target 12, referred to simply as the "target” herein below, which is mounted for example to the moving structural element 2 such as to be capable of being optically coupled to the optoelectronic device 11.
  • a measuring reflecting target referred to simply as the "target” herein below, which is mounted for example to the moving structural element 2 such as to be capable of being optically coupled to the optoelectronic device 11.
  • reflecting target is meant more generally, as will be described below, a target either reflecting or diffusing a respective electromagnetic radiation.
  • the target 12 of the optoelectronic measuring device can be fixed to the moving structural element 2 by means of a suitable anchoring system, such as of magnetic type, which comprises one or more magnets.
  • the optoelectronic device 11 comprises a laser self-mixing interferometer 20, for example a single-mode semiconductor diode laser Hitachi model HL8325G, known per se, which is suitable for emitting from a respective input/output port (not shown in the figure) a direct electromagnetic radiation to the target 12 and suitable for receiving, again on said port, a suitable fraction of the electromagnetic radiation reflected by the target .
  • the laser self-mixing interferometer 20 further defines an interference cavity between the direct electromagnetic radiation and the reflected electromagnetic radiation.
  • the direct electromagnetic radiation and reflected electromagnetic radiation preferably have a propagation direction parallel to the axis of movement X of the moving structural element 2 relative to base 1.
  • the optoelectronic measuring device 11 can advantageously provide one or more optoelectronic components, such as for example optical lenses, attenuators or amplifiers (not shown in the figures) to be interposed, for example, between the input/output port of the interferometer and the target.
  • one or more optoelectronic components such as for example optical lenses, attenuators or amplifiers (not shown in the figures) to be interposed, for example, between the input/output port of the interferometer and the target.
  • a laser self-mixing interferometer is based on a laser self-mixing effect, known per se, which occurs when the reflected electromagnetic radiation from a moving target, when it represents a fraction of the direct electromagnetic radiation, when it coherently re-enters the interference cavity and interacting therein with the direct electromagnetic radiation, causes the modification of several parameters of the direct electromagnetic radiation, such as, by way of example, laser-emission threshold, laser emission power, wavelength, spectral width.
  • the laser emission power can be monitored in order to extrapolate an information representing the distance between the interferometer and moving target.
  • the laser self-mixing interferometer 20 is suitable to output an optical interference signal SO. By processing the latter, as will be described below, it is possible to trace back the measure of a distance d between a first reference axis al and a second reference axis a2 that can be defined in the industrial machine 200.
  • the first reference axis al results to be stationary and associated with the laser self-mixing interferometer 20, while the second reference axis a2 is associated with the target 12 and thus, generally, to the moving structural element 2.
  • the first al and second a2 reference axes are parallel to each other and both orthogonal to the axis of movement X.
  • the defined (direct and reflected) electromagnetic radiations have, as stated above, propagation direction parallel to the axis of movement X, the distance d is also measured in the same direction.
  • the interferometer 20 can be mounted to the moving structural element 2, and vice versa, the target 12 can be fixed to the base 1.
  • the first reference axis al results to be stationary and associable with the target 12 whereas the second reference axis a2 corresponds to the laser interferometer 20.
  • the optoelectronic device 11 further comprises a photodetector 21, of a known type, such as a photodiode, suitable for receiving the input optical interference signal SO supplied by the interferometer 20 to convert the same to a corresponding output first electric signal SEl.
  • a photodetector 21 of a known type, such as a photodiode, suitable for receiving the input optical interference signal SO supplied by the interferometer 20 to convert the same to a corresponding output first electric signal SEl.
  • the photodiode may also be integrated in the envelope of the interferometer 20 (laser diode) .
  • the optoelectronic device 11 further comprises a processing unit UP suitable for receiving in input and processing the first electric signal SEl supplied by the photodetector 21 and outputting a second electric signal SE2 representing said measured distance d.
  • the processing unit UP is provided with at least one microprocessor and a respective memory for loading software and hardware modules (for example, a printed electric circuit on a circuit board) that can be associated with the microprocessor, for processing the first electric signal SEl.
  • the optoelectronic device 11 is suitable to supply a second electric signal SE2 to a control unit UC (schematically shown in Fig. 3) , which is operatively associated with the industrial machine 200, which is, after the second electric signal SE2 has been processed and a corresponding numeric data has been generated, suitable for commanding, as a function of said numeric data, the electric motor of the industrial machine 200 in order to move the moving structural element 2 relative to base 1.
  • a control unit UC (schematically shown in Fig. 3) , which is operatively associated with the industrial machine 200, which is, after the second electric signal SE2 has been processed and a corresponding numeric data has been generated, suitable for commanding, as a function of said numeric data, the electric motor of the industrial machine 200 in order to move the moving structural element 2 relative to base 1.
  • the optoelectronic device 11 can be suitable for directly providing an operator with the second electric signal SE2 proportional to the displacement d being measured.
  • the control unit UC is also provided with hardware (typically a microprocessor and a respective memory) and software of its own for controlling and managing the industrial machine 200 based on the distance d being measured.
  • control unit UC by means of the microprocessor thereof can carry out, while the piece 4 is being machined by the industrial machine, a comparison operation of the value of the measured distance d and a preset value that has been previously stored within said memory.
  • the control unit UC is capable of controlling the electric motor to move the moving structural element 2 thus restoring the distance between interferometer 20 and target 12 equal to the preset value .
  • control unit UC performs, upon machining the piece 4, a monitoring of the distance between interferometer 20 and target 12 such that it matches a preset value corresponding to a proper use and operation of the industrial machine 200.
  • the industrial machine 200 can be provided with a structure having a variable length 60 to protect the input/output port of the laser interferometer 20 and target 12.
  • the protection structure 60 is such as to be extended from the input/output port of the interferometer to the target such as to define an inner region within which the direct electromagnetic radiation and the reflected electromagnetic radiation can be propagated.
  • the protection structure 60 includes, for example, a plurality of tubular elements that are telescopically coupled to each other such as to be extended and contracted along the axis of movement X as the position of the moving structural element 2 changes relative to the base 1.
  • the protection structure 60 advantageously has a first end connected to the optoelectronic measuring device 11, at the input/output port, and a second end connected to the moving structural element 2 , flush with target 12.
  • the section of the plurality of tubular elements can be of any shape, being preferably circular.
  • connections cited above are preferably obtained by interposing suitable gaskets or other sealing means, between the first end and the optoelectronic device 11 and between the second end and the moving structural element 2, respectively.
  • the protecting structure 60 described above has the advantage of protecting the electromagnetic radiation, input/output port of the interferometer 20 and target 12 against impurities that may be found in the work environment, such as dirt, process waste (for example, dust, chips, splits) , industrial fluids (for example, oils, varnishes) or the like, which can cause undesired alterations and/or interruptions to the electromagnetic radiation thus affecting the operation of the optoelectronic measuring device 11.
  • the industrial machine 200 in Fig. 7 accordingly allows the optoelectronic measuring device to operate free from errors that can be generated by the environmental conditions in which the industrial machine 200 is operated.
  • the industrial machine 200 can comprise, alternatively to the plurality of tubular elements, a protection structure with a variable length, also designated with numeral 60, of a bellow type, which is suitable for carrying out the same protective function and suitable for extending and contracting along the axis of movement X of the industrial machine following the variation in the relative position between the moving structural element 2 and the base 1.
  • a protection structure with a variable length also designated with numeral 60
  • the bellow structure in Fig. 8 results to be connected to the optoelectronic device 11 and moving structural element 2 in an entirely analogous manner to the protection structure 60 in Fig. 7.
  • a plurality of sensors can be arranged within the protection structure 60 in Fig. 7 and 8, which are arranged chained to each other, and that are suitable for detecting, for example, physical parameters that can be found within the electromagnetic radiation propagation region, such as temperature, pressure, humidity. Monitoring these parameters is particularly advantageous as it allows keeping under observance, either continuously and/or discretely, the environmental conditions in which the (both direct and reflected) electromagnetic radiation is propagated, such as to be capable of correcting the measure of fluctuations induced by gradients, if required.
  • the industrial machine 200 can comprise, alternatively to the structure with tubular elements (Fig. 7) and bellow structure (Fig. 8) , any structure similar to those described above, and suitable to carry out the same protective function by extending and contracting as the position of the moving structural element is changed relative to the base, and vice versa.
  • the protection structure 60 may not be provided in the alternative case where the industrial machine 200 integrates the optoelectronic measuring device 11 along with the target 12 directly within the base 1, for example by conveniently using hollow parts of the latter, which are arranged along the axis of movement X of the machine.
  • the electromagnetic radiation, input/output port of the interferometer 20 and target 12 are advantageously protected by the inner space of the industrial machine 200, and the aid of a suitable protection structure is reasonably unnecessary.
  • the optoelectronic measuring device Il and target 12 while they are positioned along the base 1 (stationary element on the linear axis) similarly to the optical line on prior art industrial machines, has the economical advantage of maintaining a low cost regardless of the displacement measurement range d, unlike the optical line or any other graduated scale, which has an increasing cost as the value d increases.
  • the industrial machine 200 can comprise further optical measuring devices that are entirely analogous to the optical measuring device 11, which are also arranged optically coupled with the target 12, suitable for measuring any angular displacement of the moving structural element 2 relative to base 1.
  • Each of the measurable angular displacements is indicative of the rotation of target 12 about a first and second axes of rotation that are orthogonal to each other and both perpendicular to the electromagnetic radiation propagation direction emitted from the optical measuring devices and reflected/diffused by the target.
  • the self-mixing laser interferometer 20 can be advantageously aligned with a so-called fine adjustment system to be then definitely locked by means of a fixing device for adjusting screws.
  • This solution besides being very compact, also ensures an advantage in terms of rapidity and precision during the calibration of the industrial machine 200, setup flexibility, protection and resistance to mechanical stress during the machining of the piece 4, and essentially, long-term reliability.
  • the industrial machine 200 can be provided with further measuring means, also of optoelectronic type, such as, for example, one or more linear, angular or resolver encoders, which are entirely analogous to those described above with reference to the prior art .
  • further measuring means also of optoelectronic type, such as, for example, one or more linear, angular or resolver encoders, which are entirely analogous to those described above with reference to the prior art .
  • These means are suitable for measuring distances between further reference axes, which can be associated with respective structural parts of the industrial machine, in which the measured values can be integrated with the distance d being measured via the laser self-mixing interferometer .
  • the industrial machine 200 has the optoelectronic measuring device 11 being placed on the side of base 1 and the target 12 being integral with the moving structural element 2 such as to result optically coupled with the measuring device 11 for measuring the relative displacement between the moving element 12 and base 1 along the axis of movement X (linear axis) .
  • This particular configuration which is structurally very similar to prior art linear encoders, is cost-effective and results to be quite simple to assemble by an operator; it also allows measuring any deformation between the base 1 and moving structural element 2 that a linear encoder cannot detect.
  • the industrial machine 200 can be provided, for example, with measuring means, alternatively or in combination with the machining tool 50, such as a measuring probe, known per se.
  • the machining provides that a hole is made in the piece 4, which preferably has orthogonal direction to the axis of movement X, using the mechanical tool 50, for example a drill being mechanically connected to the industrial machine 200.
  • the piece 4 is fixed to, by means of the suitable claws, the moving structural element 2. While the machine is being switched on, the optoelectronic measuring device 11 is operated. Next, an operator of the machine operates the electric motor to move, relative to base 1, the moving structural element 2 in order to cause the industrial machine to adopt a first operating configuration for carrying out said hole within the piece 4 in a determined location selected during the design step. If required, in order to facilitate achieving the first operating configuration of the machine, the operator can also adjust the mechanical tool 50 such as to align or approach the latter to the piece 4.
  • the optoelectronic measuring device 11 provides a first preset value of distance d between the laser interferometer 20 and target 12 corresponding to said first operating configuration.
  • This first preset value is then stored within the memory of control unit UC or, alternatively, can be selected from a series of values that have been previously stored within the same memory of the unit UC.
  • the industrial machine 200 starts, upon command by the operator, machining the piece 4 and, simultaneously, the optoelectronic device 11 and control unit UC become activated for monitoring that the distance d between the 20 and target 12 is maintained equal to the first preset value.
  • the distance d is left unchanged as much as possible.
  • the laser self-mixing interferometer 20 in order to carry out said monitoring, emits from the input/output port, a direct electromagnetic radiation to target 12.
  • the target 12 receives the direct electromagnetic radiation, it reflects/diffuses, in turn, this electromagnetic radiation to the input/output port of the interferometer 20.
  • the latter by entering coherently the laser cavity of the interferometer 20, due to the interferometer effect described above, allows the latter to generate an optical signal SO that is representative of the distance d between the target 12 and interferometer 20.
  • a photodetector 21 detects the optical signal SO and converts it to a corresponding first electric signal SEl that is, in turn, sent to the input of a processing unit UP.
  • the latter provides to process the first electric signal SEl to generate a second electric signal SE2 also indicative of the distance d measured between the laser interferometer 20 and target 12.
  • control unit UC with which the industrial machine is provided receives said second electric signal SE2 and converts it, via the microprocessor thereof, to a corresponding numeric data.
  • the control unit UC then compares said numeric data with the first preset value stored within the respective memory.
  • control unit UC automatically provides to operate the electric motor in order to move, relative to the base 1, the moving structural element 2, and thus also the piece 4, such that the industrial machine 200 goes back, from a second operating configuration adopted during the machining, to the first operating configuration as designed and set by the operator for the proper execution of the hole in the piece 4.
  • control unit UC does not send any command to the electric motor as the measured distance d is still equal to the first preset value and thus the machining is proceeding in a proper manner since the industrial machine 200 is maintaining the first operating configuration.
  • Michelson laser interferometer comprises a laser source, such as a Helium-Neon frequency-stabilized source, for generating a direct electromagnetic radiation to a moving target.
  • Michelson interferometers comprise, for example, a stationary retroreflector and a beam splitter such as division e recombination (interference) means of direct electromagnetic radiation and corresponding electromagnetic radiation reflected and/or diffused by the moving target in order to assess the displacement, if any, of the target relative to the source.
  • Michelson laser interferometer is operatively associated with the photodetector and qontrol unit of which the operation has been described above with reference to the laser self-mixing interferometer 20.
  • a Doppler laser interferometer can be also used, which is suitable for optically co-operating with target 12.
  • this interferometer comprises a helium- neon laser for emitting the direct electromagnetic radiation, a beam modulator/splitter and a combiner in which the interference occurs between the reflected electromagnetic radiation from the target and a reference electromagnetic radiation that is obtained, by the modulator/splitter, from the direct electromagnetic radiation.
  • a Doppler laser interferometer is described in US-A-4715706.
  • the object of the invention is fully achieved in that the industrial machine described herein comprises a laser interferometer suitable for ensuring a measuring that is not affected by the geometric deformations of the axis with which it is associated, unlike what occurs, for example, in those industrial machines that are provided with a linear encoder and optical line.
  • the measure of the distance between laser interferometer and target is not sensitive to local structural deformations and, at the same time, ensures monitoring the displacement dynamic of only the target, rigidly integral with the moving axis, which is, in turn, given by the composition of the displacement being set and that being induced by the geometric alterations.
  • the configuration of the industrial machine which provides the optoelectronic measuring system to be integrally fixed to the base 1, by means of a suitable anchoring system of magnetic type is different from the prior art industrial machine which integrates the linear encoder due to its great measuring flexibility at low costs, regardless of the distance between interferometer and target.
  • the solution comprising the use of a laser self- mixing interferometer is particularly advantageous as it is cost-effective and easy to install, which ensures a good effectiveness and measuring precision due to the small number of optical components with which it is provided .
  • Another advantage deriving from the use of a laser interferometer as compared with, for example, a prior art linear encoder as mentioned above is the versatility in selecting the configuration thereof that can be suitably adapted to the geometry of an industrial machine.
  • the optoelectronic device using a laser interferometer further offers a greater freedom on selecting the positioning of the target according to which the measuring is carried out. For this reason, the
  • the laser interferometer can be used not only during the machining of the workpiece, but also, as stated above, during the general operation of the machine, and also for calibrating the industrial machine to which the interferometer results to be fixed, or more generally, associated.
  • the laser self-mixing interferometer allows the module and displacement direction of a target to be immediately acknowledged via an individual interferometry channel .
  • the optoelectronic components required for laser self-mixing interferometry currently on the market, such as the semiconductor diode are available off the shelf at a very low cost and exhibit a proved operative reliability and duration over time.
  • these devices have such compactness and robustness that the self-mixing interferometer results to be ideal in a typically industrial work environment.
  • Michelson and Doppler laser interferometers are also available on the market and can offer good performance and proved reliability even in those applications for which they can be intended within the scope of the present invention.

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  • Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Electromagnetism (AREA)
  • Optics & Photonics (AREA)
  • Machine Tool Sensing Apparatuses (AREA)
  • Length Measuring Devices By Optical Means (AREA)

Abstract

L'invention concerne une machine industrielle (200) comprenant: - un élément structural mobile (2) pour adopter différentes positions dans des configurations de fonctionnement correspondantes de la machine (200); des moyens de mesures optoélectroniques (11, 12) d'une distance (d) entre un premier axe de référence (a1) et un second axe de référence (a2) associés audit élément structural (2). La machine industrielle est caractérisée par le fait que lesdits moyens de mesure optoélectroniques (11, 12) comprennent un interféromètre à laser (20) et une cible réfléchissante de mesure (12) qui sont optiquement couplés l'un à l'autre et chacun étant associé à l'un desdits axes de référence, ledit interféromètre à laser comprenant une source laser pour émettre un rayonnement électromagnétique direct vers ladite cible (12) et des moyens d'interférence entre un rayonnement électromagnétique réfléchi à partir de ladite cible et un rayonnement électromagnétique de référence obtenu à partir du rayonnement électromagnétique direct.
EP06821769A 2006-11-08 2006-11-08 Machine industrielle dotée de moyens de mesure interférométrique Withdrawn EP2089183A1 (fr)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/IT2006/000780 WO2008056383A1 (fr) 2006-11-08 2006-11-08 Machine industrielle dotée de moyens de mesure interférométrique

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EP2089183A1 true EP2089183A1 (fr) 2009-08-19

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EP (1) EP2089183A1 (fr)
CN (1) CN101583462A (fr)
WO (1) WO2008056383A1 (fr)

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CN102407414A (zh) * 2010-11-26 2012-04-11 昆山市瑞捷精密模具有限公司 垂直立焊治具
CN102407417A (zh) * 2010-12-08 2012-04-11 昆山市瑞捷精密模具有限公司 任意角立焊治具
JP6008487B2 (ja) * 2011-06-16 2016-10-19 三菱重工工作機械株式会社 工作機械
CN110631513B (zh) * 2018-05-18 2021-03-30 安徽大学 双正交平面镜内入射型角度传感测量装置及方法
EP3696631B1 (fr) 2019-02-13 2023-04-05 SCM Group S.p.A. Centre d'usinage pour des pièces en bois équipé d'un système de mesure
CN109732402B (zh) * 2019-03-14 2020-02-11 西安交通大学 基于激光干涉仪的多线机床空间几何误差测量辨识方法
CN112113509B (zh) * 2019-06-20 2022-06-17 上海微电子装备（集团）股份有限公司 龙门式测量装置及龙门式测量方法

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WO2008056383A1 (fr) 2008-05-15
CN101583462A (zh) 2009-11-18

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