Device and method for processing rotation-dependent measured values
Patent Information
- Application Number
- JP2021097279
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2020-09-07
- Filing Date
- 2021-06-10
- Publication Date
- 2025-07-15
- Estimated Expiration
- 2041-06-10
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an apparatus for processing a rotation-dependent measured value according to claim 1 of the present application, and a corresponding method according to claim 8 of the present application.
Background Art
[0002] In automation technology, a rotating shaft directly or indirectly driven by an electric motor forms the basis of a plurality of motion sequences. Even without an external force already, for example, mechanical vibrations caused by unbalance can cause the rotating shaft to affect mechanical components. Moreover, when an external force also acts on the shaft, such effects are amplified many times, especially when the resonance frequency of the mechanical components is affected.
[0003] In this case, a particularly sensitive technical area is the high-precision machining of workpieces in machine tools. Here, the motor spindle is an important component because it operates at different speeds and has a shaft that is affected by large lateral forces and dynamically variable forces according to the machining step.
[0004] Taking milling as an example, during operation, a plurality of forces are generated by machining with cutting. These plurality of forces are also affected by the feed rate and the number and condition of the cutting edges of the milling tool used. These can cause dynamic strain of the shaft and may have various negative effects on the machine tool.
[0005] In order to be able to analyze such effects, various sensors are used, for example, an acceleration sensor or a structure-borne noise sensor for grasping vibrations or a strain gauge for detecting strain.
[0006] Patent Document 1 describes a method for monitoring the operating parameters of a machine tool. For this purpose, multiple measurements are performed using sensors at regular time intervals, and the measured values are displayed graphically. A drawback of this method is that, especially at low speeds, a very large number of measurements are taken for each rotation of the shaft, so the evaluation requires a large amount of memory and computation. [Prior art documents] [Patent Documents]
[0007] [Patent Document 1] European Patent Application Publication No. 2924526 [Overview of the Initiative] [Problems that the invention aims to solve]
[0008] The object of the present invention is to provide a device that provides result data that enables easy evaluation of the influence of a rotating shaft on mechanical parts. [Means for solving the problem]
[0009] This problem is solved by the apparatus according to claim 1.
[0010] A device for processing rotation-dependent measurements is provided, comprising a data converter, a sequence controller, and an output interface. The device is The data converter is capable of supplying a series of measurements at constant time intervals, wherein these measurements depend on the rotation of the shaft, and at least one of these measurements is an angular value indicating the angular position of the shaft. The data converter is configured to divide one rotation of the shaft into n sectors, to assign an incoming measurement to a single sector using one of the angle values as the reference angle value, and to accurately determine one result value for each sector according to the rotation of the shaft for each set of measurements, and • Result values can be output to the output interface.
[0011] Furthermore, an objective of the present invention is to provide a method for obtaining result data that enables easy evaluation of the influence of a rotating shaft on a mechanical component.
[0012] This problem is solved by the method according to claim 8.
[0013] A method is intended for operating a device for processing rotation-dependent measurements, comprising a data converter, a sequence controller, and an output interface, and this method is The data converter is supplied with a series of measurements at regular time intervals, the measurements being dependent on the rotation of the shaft, and at least one of the measurements being an angular value indicating the angular position of the shaft. • In the data converter, one rotation of the shaft is divided into n sectors, and using one of the angle values as the reference angle value, the arriving measurement is assigned to one sector, and for each series of measurements, one result value is precisely determined for each sector according to the rotation of the shaft, and The result value is output to the output interface.
[0014] Further advantages of the apparatus or method according to the present invention can be found in the dependent claims or the embodiments described. [Brief explanation of the drawing]
[0015] [Figure 1] A schematic diagram of a machine tool with a motor spindle is shown. [Figure 2] An embodiment of the apparatus according to the present invention is shown. [Figure 3] A signal diagram for the embodiment shown in Figure 2 is presented. [Figure 4] A table of values illustrating the method according to the present invention is shown. [Figure 5A] An alternative embodiment of the measurement system is shown. [Figure 5B] Shows another embodiment of the measurement system. [Figure 5C] Shows another embodiment of the measurement system. [Figure 6A] Shows an alternative embodiment of the measurement system. [Figure 6B] Shows another embodiment of the measurement system. [Figure 7] Shows another embodiment of the device according to the present invention. [Figure 8] Shows another embodiment of the device according to the present invention.
Embodiments for Carrying Out the Invention
[0016] In the following description, in advantageous embodiments of the present invention, the reference numerals of the components and functional groups shown in one figure are retained in the figures described later.
[0017] FIG. 1 shows a machine tool having a motor spindle 10 in a simplified manner. The central component is a spindle motor 1 having a shaft 2. At one end of the shaft 2, a tool 4 (for example, a milling tool) is arranged. In order to fix the tool 4 to the shaft 2, a tool holder (not shown), for example, a chuck or a hollow tool shank, is provided. An angle measuring device 5 (rotary encoder) is also mechanically connected to the shaft 2. This connection is made via a mechanical connection (not shown) that connects the rotatable shaft of the angle measuring device 5 to the shaft 2. In this way, the angular position and / or the number of rotations executed by the shaft 2 can be measured by the angle measuring device 5. The support of the shaft 2 within the housing of the spindle motor 1 is effected by rolling bearings.
[0018] During machining of the workpiece 6, the shaft 2 rotates at a variable rotational speed N, and the relative motion of the motor spindle 10 with respect to the workpiece 6 brings the tool 4 into contact with the workpiece 6. In this way, for example, during milling, the desired contour is milled from the workpiece 6. The relative motion can be performed along linear drive axes X, Y, and Z, and so-called pivot axes A and B are also provided. As a result, in the example shown, motion along five motion axes X, Y, Z, A, and B is possible. The motion along each axis is controlled by a servo drive (not shown), which drives the corresponding mechanical components. Further position measuring devices 20X, 20Y, 20Z, 20A, and 20B are provided on the machine tool to determine the position of each motion axis X, Y, Z, A, and B.
[0019] Furthermore, the motor spindle 10 may be equipped with a multi-position measuring device 8, the structure and function of which will be explained in conjunction with Figure 7.
[0020] The rotation of shaft 2 can have various effects on the operation of the machine tool. Even if tool 4 is not in contact with the workpiece 6, vibrations dependent on rotational speed can occur due to shaft imbalance, bearing clearance of rolling bearings, eccentricity errors, etc. The forces acting on tool 4 during machining of workpiece 6 often have a more serious impact on the machine tool, often in the form of mechanical vibrations.
[0021] Furthermore, the motor spindle 10 is equipped with a sensor 30, which can be used to measure further aspects of the machine's condition. In this case, possible sensors include acceleration sensors, vibration sensors, solid-borne sound sensors, strain gauges, and current measuring resistors.
[0022] The measurement values from the angle measuring device 5, the position measuring devices 20X, 20Y, 20Z, 20A, 20B, the multi-position measuring device 8, and the sensor 30 can be transmitted to the control device 40 via appropriate cables. The control device 40 is equipped with an interface for connecting the cables and is used to understand and process the measurement values.
[0023] Figure 2 shows one embodiment of the apparatus according to the present invention, based on the mechanical architecture shown in Figure 1.
[0024] The core function of the apparatus according to the present invention is the processing of a series of rotation-dependent measurements. These are measurements that may be affected by the rotation of shaft 2. These are measurements that are affected not only by obvious effects such as changes in the angular position of shaft 2 itself, but especially by forces generated by the rotating shaft 2 itself, or by forces acting on shaft 2 during the operation of the machine. Various measuring systems are provided to measure and provide the measurements. A first measuring system 70 is suitable for measuring the angular position of shaft 2. This first measuring system comprises an angle measuring device 5, a data transmission channel 50, and a data interface 43. Furthermore, two other measuring systems 80 and 90 are provided, the second measuring system 80 having a position measuring device 20X for measuring motion in the direction of the motion axis X, in contrast to the position measuring devices 20X, 20Y, 20Z, 20A, 20B shown in Figure 1, and the third measuring system 90 having a (digital in this example) sensor 30 as a measuring device. Furthermore, the second measurement system 80 and the third measurement system 90 each have data transmission channels 51 and 52 and data interfaces 44 and 45, respectively.
[0025] The selection of position measuring device 20X is arbitrary and not limited. Naturally, each position measuring device 20X, 20Y, 20Z, 20A, and 20B (which should be used to investigate the influence of the position measuring device on the rotating shaft 2) can be used as a measuring unit in a further measuring system.
[0026] A measurement system within the scope of the present invention is operated by an external signal and comprises all the necessary components for performing multiple measurements and for providing or outputting determined measurement values digitally. Each assembly comprises at least one measuring device, a transmission channel, and an interface. Using at least one measuring device, at least one measurement variable to be examined can be grasped and, depending on the design of the measuring device, supplied to the interface via the transmission channel in the form of a digital measurement value and / or a measurement signal to be evaluated.
[0027] In the first measurement system 70, the angular position of the shaft 2 can be measured by the angle measuring device 5. It operates as a so-called absolute angle measuring device. Angle measurement is initiated by sending a request command RQW from the data interface 43 to the angle measuring device 5 via the data transmission channel 50. The resulting angle value MW is transmitted in the reverse direction from the angle measuring device 5 to the data interface 43 via the data transmission channel 50.
[0028] Similarly, the position value MX can be measured by the second measurement system 80 using the position measuring device 20X, and can be transmitted to the data transmission channel 51 and, via the data transmission channel 51, to the data interface 44. The measurement is initiated by the request command RQX.
[0029] The sensor 30 in the third measurement system 90 operates as a digital sensor, and therefore measurements are also performed upon arrival of a request command RQS, which is then transmitted to the data interface 45 via the data transmission channel 52.
[0030] The control device 40 comprises a sequence controller 46, a data converter 60, and an output interface 62. Furthermore, the data interfaces 43 to 45 of the measurement systems 70, 80, and 90 are part of the control device 40.
[0031] In the example described, all data interfaces are designed for point-to-point data transmission. Specifically, data interfaces 43 to 45 communicate with connected digital measuring devices (angle measuring device 5, position measuring device 20X, and sensor 30) via the corresponding data transmission channels 50 to 52.
[0032] The sequence controller 46 generates measurement pulses MP at regular time intervals and supplies them to the measurement systems 70, 80, and 90 via signal cables 47. The data interfaces 43 to 45 then request measurement values via the data interfaces 43, 44, and 45 by transmitting request commands RQW, RQX, and RQS to the angle measuring device 5, position measuring device 20X, and sensor 30. The measurement values MW, MX, and MS arriving at each data interface 43, 44, and 45 as a result of these request commands are supplied to the data converter 60. This procedure results in a series of measurement values where the individual measurement values MW, MX, and MS of the measurement systems 70, 80, and 90 are measured almost simultaneously. That is, the measurement values MW, MX, and MS are time-based.
[0033] It should be noted that, at present, using the same data interface is not a requirement. Rather, any data interface that supports the request command is suitable, and the request command can be represented by any signal or any sequence of signals. The medium on which the data transmission channels 50, 51, and 52 are formed is also arbitrary. For example, it can be a wire, a light guide, or a wireless connection. In the case of a wire, signal transmission can be performed differentially, for example, according to the known RS-485 standard. As a result, it is possible to have a pair of lines for the bidirectional data channels and, in some cases, another pair of lines for one clock signal channel.
[0034] Therefore, the data converter 60 converts the time-based measurements generated by the measurement systems 70, 80, and 90 into angle-based, virtual result values. For this purpose, one rotation of the shaft 2 is divided into n sectors, and a virtual, angle-based measurement is determined for each of the n sectors. The measurement MW from the measurement system 70 is used as the reference for the current angular position of the shaft 2, which serves as the basis for the current assignment of each sector.
[0035] The result value is output to the output interface 62, and from this output interface, the result value can be output to subsequent electronic devices for further evaluation. Advantageously, the result value can be stored in the output interface 62, and as a result, output can also be performed at a later time.
[0036] In summary, the control device 40 forms a measurement module, which has an interface for connecting a measuring device via a suitable transmission channel, and also has processing means for processing the measured values measured by the present invention into result values and an output interface for outputting those result values. In this case, the control device 40 may be an independent device, or it may be implemented as a measurement module for a mechanical controller.
[0037] Figure 3 shows a signal diagram for the embodiment shown in Figure 2.
[0038] The top row of the signal diagram shows the measurement pulse MP, which is output from the sequence controller 46 to the measurement systems 70, 80, and 90 via the signal cable 47 at a constant measurement interval T. The arrival of the measurement pulse MP can be recognized by monitoring its respective signal characteristics, for example, by the arrival of a defined signal edge or a change in the signal level.
[0039] The following column symbolically illustrates the communication following the arrival of measurement pulses MP in measurement systems 70, 80, and 90 via data transmission channels 50 to 52, with signals directed towards the angle measuring device 5, position measuring device 20X, and sensor 30 shown above the horizontal line, while signals directed towards data interfaces 43 to 45 are shown below the horizontal line. This diagram does not allow for inference of signal polarity or the number of transmission lines intended for transmission.
[0040] Thus, when a measurement pulse MP arrives, data interfaces 43 to 45 directly transmit request commands RQW, RQX, and RQS to the corresponding measuring devices, namely the angle measuring device 5, the position measuring device 20X, and the sensor 30, via data transmission channels 50 to 52. These devices then similarly perform multiple near-simultaneous measurements and generate the resulting measurements (angle value MW, position value MX, and sensor value MS), which they transmit to data interfaces 43 to 45.
[0041] The types of request commands RQW, RQX, and RQS are interface-specific. As shown in Figure 3, the data interfaces in which the request commands RQW, RQX, and RQS are defined data words (command words) are known. For other data interfaces, the arrival of a signal edge is already interpreted as a request command RQW, RQX, or RQS.
[0042] The measured values MW, MX, and MS are output from the measurement systems 70, 80, and 90 to the data converter 60 for further processing.
[0043] The resulting values are determined by the data converter 60 based on the received measurements in MW, MX, and MS. A suitable and preferred method for this purpose is described below with reference to Figure 4.
[0044] Figure 4 shows a first table containing the sequentially measured values MW, MX, and MS. Here, the angle value MW is given in degrees [°], the position value MX in millimeters [mm], and the sensor value MS is assumed to be a unitless integer value, for example, containing a 16-bit range value. Furthermore, Figure 4 shows a second table containing the resulting values EW, EX, and ES determined by a data converter from the values in the first table.
[0045] For the following embodiment, assume that one rotation of shaft 2 is equally divided into 120 similar sectors SEC. Thus, each sector SEC contains an angular range of 3°. Which sector SEC the currently measured values MW, MX, and MS are assigned to is determined by the angular value MW, which is used as the reference angular value. Thus, for example, angular values MW with table values of 0.9° and 2.1° are assigned to sector 1. This means that position values MX with table values of 113.43 mm and 114.98 mm and sensor values MS with table values of 5854 and 5850 are also assigned to sector 1, since they were measured at the same time as the corresponding angular values MW, respectively.
[0046] According to the present invention, the data converter 60 determines one result value for each sector SEC from at least one measurement series among the measurement systems 70, 80, and 90. Similar to the measured values (angle value MW, position value MX, sensor value MS), these result values are accompanied by reference symbols EW, EX, and ES, respectively, supplemented by the sector number.
[0047] The following methods for determining the result value have proven to be particularly advantageous:
[0048] The first method is to select the first measurement after the sector change (or the last measurement before the sector change) as the result values EW, EX, and ES. This method is particularly simple because it does not require calculation. It is advantageous to select the measurement interval T so that multiple measurement values MW, MX, and MS are measured for each sector SEC during operation. In the simple example described, the angle result value EW1 = 0.9°, the position result value EX1 = 113.43 mm, and the sensor result value ES1 = 5854 occur when the first measurement after the sector change is selected for sector SEC = 1 in the positive rotation direction.
[0049] In the second method, the average value of all measured values MW, MX, and MS within a single sector SEC is formed as the result values EW, EX, and ES. This method is usable when at least two measured values MW, MX, and MS are measured per sector SEC. A special advantage of this method is that low-pass filtering of the measured values MW, MX, and MS is achieved. Here, for sector SEC=1, the angle result value EW1=1.5°, the position result value EX1=114.205mm, and the sensor result value ES1=5852 are obtained.
[0050] The third method is based on calculating a hypothetical measurement of the angular position at the center of the current sector SEC from at least two measured values MW, MX, and MS within the sector SEC, as the resulting values EW, EX, and ES. Here, an appropriate calculation method, in particular interpolation methods such as linear interpolation, polynomial interpolation, and spline interpolation, can be used. This method reduces the sharp rise between the resulting values EW, EX, and ES (these resulting values are related to the rotational motion of shaft 2 and result in asynchronous measurements of measured values MW, MX, and MS (jitter)), and is therefore very precise. With linear interpolation, for example, for sector SEC=1, the resulting angular value EW1=1.5°, the resulting position value EX1=114.205mm, and the resulting sensor value ES1=5852 (calculated with the sector center point at 1.5°).
[0051] In all methods, the measured values MW, MX, and MS are assigned to sectors SEC based on the angle value MW measured by the measurement system 70 as the reference angle value.
[0052] The determined and provided result values EW, EX, and ES can be output to subsequent electronic devices (not shown) via the output interface 62 for further evaluation. Alternatively, the output interface 62 may be implemented as a graphic interface to which a display device, such as a monitor, can be connected, and the progress of the result values EW, EX, and ES can be graphically displayed on this monitor. In this case, the progress of the result values EW, EX, and ES can be visually evaluated or judged by an observer.
[0053] Figures 5A to 5C show further advantageous embodiments of the measurement system. In this case, the measurement system described in Figures 5A and 5B can be replaced, for example, with the measurement system 80 in Figure 2, and can be used in place of the measurement system 90 in Figure 5C.
[0054] The measurement system 180 shown in Figure 5A includes an incremental encoder 120, the analog position signals sin, cos, and ref of this incremental encoder are supplied to the processing interface 144 via a signal transmission channel 151. The incremental encoder 120 may be implemented as an angle measuring device (rotary encoder) or a length measuring device.
[0055] The position signals sin, cos, and ref of the incremental encoder 120 are generated by scanning a regular scale structure, as is known in the prior art. At a constant speed or moving speed, the position signals sin and cos are approximately sinusoidal and exhibit a phase shift of 90° from each other. The number of scale periods of the scale structure corresponds to the number of signal periods of the position signals sin and cos. Therefore, position determination is possible by evaluating the position signals sin and cos together with the position signal ref which defines the reference position.
[0056] The processing interface 144 determines the current position value MX relative to the reference position by evaluating (measuring) the signal period of the position signals sin and cos, and in some cases, a portion of the signal period (interpolation).
[0057] When the measurement pulse MP arrives, the further measurement system 180 outputs the current position value MX via the processing interface 144.
[0058] The measurement system 280 shown in Figure 5B also includes an incremental encoder 220. However, unlike in Figure 5A, it outputs digital position signals A, B, and R to the processing interface 244 via the signal transmission channel 251.
[0059] Position signals A and B are rectangular but are 90° out of phase with respect to each other. Position signal R is used to determine the reference position and is similarly rectangular in this case.
[0060] The processing interface 244 determines the current position value MX by counting the signal periods or signal edges of position signals A and B with respect to the reference position.
[0061] Here too, the further measurement system 280 outputs the current position value MX via the processing interface 244 after the arrival of the measurement pulse MP.
[0062] Further measurement system 190 from Figure 5C includes an analog sensor 130, the analog sensor signal S of which is supplied to the processing interface 145 via a signal transmission channel 152.
[0063] The analog sensor 130 may include an electrical circuit or any other component that converts the variable to be measured into an electrical signal. This may include a variable resistor, such as a strain gauge (DMS), or a constant measuring resistor, such as a constant measuring resistor for measuring the motor current of the spindle motor 1.
[0064] The processing interface 145 is configured to be suitable for generating and outputting a sensor value MS from the sensor signal S after the arrival of the measurement pulse MP. For this purpose, an A / D converter and an arithmetic circuit may be provided.
[0065] Figures 6A and 6B show alternative embodiments of a measurement system that can replace the measurement system 70 in Figure 2.
[0066] The measurement system 170 shown in Figure 6A corresponds to the measurement system 180 shown in Figure 5A. However, since this measurement system is used to measure the angular position of shaft 2, in this case the measuring device is limited to an incremental rotary encoder 105, whose analog position signals sin, cos, and ref are supplied to the processing interface 143 via the signal transmission channel 150. Similar to the measurement system 70, the measurement system 170 outputs an angular value MW as a result of the arrival of one measurement pulse MP.
[0067] In comparison with Figure 6A, and similarly to Figure 5B, the measurement system 270 includes an incremental rotary encoder 205 that outputs digital position signals A, B, and R to the processing interface 243 via a signal transmission channel 250. Here again, the arrival of a measurement pulse MP results in the output of an angle value MW.
[0068] Figure 7 shows the basic structure of the multi-position measuring device 8. This multi-position measuring device 8 includes a measuring scale 12 and three scanning heads 14, 15, and 16.
[0069] The measuring scale 12 is arranged in a ring shape around the shaft 2 and is connected to the shaft in a rotationally immobile manner. This measuring scale can be formed directly on the shaft 2, for example, as a series of magnetic regions. Alternatively, this measuring scale can be placed on a scale carrier, which is connected to the shaft 2. In this way, as the shaft 2 rotates, the measuring scale 12 moves through the measuring heads 14, 15, and 16.
[0070] The scan heads 14, 15, and 16 are statically mounted to the shaft 2, for example, by being connected to the housing of the motor spindle 10. A substantially ring-shaped carrier element surrounding the shaft 2 can be provided as a carrier for the scan heads 14, 15, and 16. Advantageously, the scan heads 14, 15, and 16 are distributed and arranged around the shaft 2 at constant angular intervals. As a result, the three scan heads 14, 15, and 16 have an ideal (but not absolutely necessary) angular interval of 120°.
[0071] In a simpler variation, only two measuring heads can be used, in which case a 180° angular spacing is preferred.
[0072] The scanning heads 14, 15, and 16 are configured in a manner suitable for scanning the measurement scale 12 and obtaining position-dependent signals from it, from which the angular position of the shaft 2 can be determined. Various physical scanning principles can be used here, particularly magnetic, optical, or inductive scanning principles.
[0073] In the described embodiment, the scanning heads 14, 15, and 16 are operated as an absolute measuring device in conjunction with the measuring scale 12. That is, the scanning of the measuring scale 12 by the scanning heads 14, 15, and 16 generates digital angle values MW1, MW2, and MW3.
[0074] In an ideal configuration and with perfect concentricity of shaft 2, the scanning heads 14, 15, and 16 measure the same angular position, or the angular values MW2 and MW3 measured by the scanning heads 15 and 16 have a constant offset of 120° or 240° with respect to the angular value MW1 of the first scanning head 14.
[0075] In contrast, in actual operation, for example, while the motor spindle 10 is milling the workpiece 6, a force acts radially on the shaft 2, and the shaft 2 deviates in relation to the stationary scanning heads 14, 15, and 16 (in Figure 7, instead of the complex force curves that occur during the machining process on the rotating shaft 2, only the force vector F that moves the rotation center point M and the shaft 2 from the ideal position to the rotation center point M' and the operating position shown by the dashed line is indicated by symbols). This also affects the measured angle values MW1, MW2, and MW3, so evaluating the errors in the angle values MW1, MW2, and MW3 resulting from the deflection of the shaft 2 makes it possible to inversely estimate the resulting force or dynamic force curve. In particular, the course of the displacement of the shaft 2 can be calculated from the course of the angle values MW1, MW2, and MW3.
[0076] The measurement system shown in Figure 7 comprises two measurement systems 370 and 380. Measurement system 370 includes a first scanning head 14 and is connected to a data interface 343 via a data transmission channel 351. To initiate measurement, the data interface 343 sends a request command RQW1 to the scanning head 14, which then performs the measurement and sends the angle value MW1 back to the data interface 343. As in the previously described embodiment, the measurement process is driven by a measurement pulse MP, which is supplied to the measurement system 370 by a sequence control unit 46.
[0077] The measurement system 380 includes a second scan head 15 and a third scan head 16, both of which are connected to a bus interface 344 via a data transmission channel 352. The bus interface 344 can communicate with both scan heads 15 and 16. As a result, the bus interface 344 sends a first request command RQW2 to scan head 15 and a second request command RQW3 to scan head 16 to initiate measurement. Alternatively, a common request command may be provided to initiate measurement, and this request command is sent to both scan heads 15 and 16 (broadcast).
[0078] Therefore, one bus interface 344 is usable when at least two digital measuring devices, in this case scan heads 15 and 16, are connected to it. Furthermore, the scan heads 15 and 16 send the measured angle values MW2 and MW3 back to the bus interface 344. Thus, unlike the aforementioned measuring system, the measuring system 380 is configured to measure and output two measurements, specifically two angle values MW2 and MW3.
[0079] The data interface 343 and the bus interface 344 are located in the control device 340. The control device 340 further comprises a sequence control unit 46, a data converter 60, an output interface 62 (which has already been described in conjunction with Figure 2), and an arithmetic unit 64.
[0080] In this embodiment, the angle values MW1, MW2, and MW3 measured by the measurement systems 370 and 380 are not supplied directly to the data converter 60, but to the calculation unit 64. The calculation unit 64 calculates an intermediate value Z, which indicates the progress of the deflection of the shaft 2, from the progress of the angle values MW1, MW2, and MW3.
[0081] Similar to the measurement of angular values MW1, MW2, and MW3, the calculation of the intermediate value Z is performed on the time pattern of the measurement pulse MP. This results in a series of intermediate values that are supplied to the data converter 60 as measured values, and the data converter converts the series of intermediate values into an angle-based displacement result value EV. That is, it is converted to one displacement result value EV per sector SEC.
[0082] In this embodiment, the angle value MW1 measured by the scanning head 14 is supplied to the data converter 60 as a reference angle value MW to be considered in determining each current sector SEC. This is advantageous if measurement errors arising from the displacement of the shaft 2 in the measurement of the angle value MW1 can be tolerated for further evaluation.
[0083] Figure 8 shows a further embodiment of the measurement system according to the present invention. It differs from the measurement system in Figure 7 only in the formation of the reference angle value MW. For this purpose, the control device 440 is provided with a second calculation unit 66 to which angle values MW1, MW2, and MW3 are supplied. The second calculation unit 66 calculates a corrected angle value MW as an intermediate value from the angle values MW1, MW2, and MW3, for example by averaging. This corrected angle value MW becomes the reference angle value in the data converter. In this way, the determination of the current sector SEC in the data converter does not depend on the shaft displacement. As a result, even higher accuracy of the resulting value is achieved.
[0084] Of course, when calculating the reference angle value MW, the offset, which is limited to 120° or 240° between angle values MW1, MW2, and MW3, must be taken into account, depending on the arrangement of the scanning heads 14, 15, and 16.
[0085] Multiple position measuring devices 8 may also have additional scanning heads (a fourth scanning head 114 is shown), as indicated only by dashed lines in Figure 8. These may measure vertical displacement relative to the plane of the shaft or the drawing of the measuring scale 12, provided that the measuring scale 12 has a scale structure that allows measurement in the vertical measuring direction. Measurements from the additional scanning heads may be fed directly to the data converter and converted thereto into angle-based results, but these measurements may also be fed to calculation units 64, 66 for consideration when calculating the intermediate value Z and / or reference angle value MW.
[0086] As suggested, communication with another scan head can be done via a bus connection (in which case data interface 343 should function as a bus interface) or via a separate data interface.
[0087] Alternatively, each measuring head 14, 15, and 16 may also be configured in a suitable shape to measure displacement and angular values perpendicular to the plane of the drawing.
[0088] The measuring heads 14, 15, and 16, together with the (absolutely coded) measuring scales 12, each form an absolute (digital) measuring device. Alternatively, an incremental measuring scale can be used, and it should be noted that an incremental rotary encoder can be formed in conjunction with a measuring head suitable for evaluating incremental signals. In a more consistent form, if a processing interface is used instead of the data interface 343 or bus interface 344, there will be three measuring systems corresponding to the embodiments in Figure 6A or 6B.
[0089] The present invention is not limited to the embodiments described, but rather can be selectively implemented by those skilled in the art within the scope of the claims.
[0090] Similarly, the present invention is not limited to use in conjunction with machine tools for milling. The present invention can be advantageously used in all machines and equipment in which the influence of a rotating shaft on various components of the machine or equipment to be considered should be analyzed. In addition to machines for milling, machines for grinding, turning, or conveyor systems can also be evaluated in particular.
Claims
1. An apparatus for processing rotation-dependent measurements, comprising a data converter (60), a sequence controller (46), and an output interface (62), the apparatus comprising: the data converter (60) is capable of being supplied with a series of measurements (MW, MX, MS, MW1, MW2, MW3, Z) at regular time intervals of a measurement interval (T), these measurements being dependent on the rotation of the shaft (2), and at least one of the measurements being an angle value (MW, MW1, MW2, MW3) indicative of the angular position of the shaft (2); the data converter (60) is configured to divide one revolution of the shaft (2) into n sectors (SEC) and to assign the arriving measurements (MW, MX, MS, MW1, MW2, MW3, Z) to one sector (SEC) using one of the angle values (MW, MW1) as a reference angle value, and to accurately determine one result value (EW, EX, ES, EV) for each sector (SEC) depending on the revolution of the shaft (2) for each series of measurements (MW, MX, MS, MW1, MW2, MW3, Z); and The result values (EW, EX, ES, EV) can be output to the output interface (62); An apparatus characterized in that
2. At least one measurement system (70, 80, 90, 170, 180, 190, 270, 370, 380) is provided, the measurement system comprising an interface (43, 44, 45, 143, 145, 243, 244, 342, 344), a transmission channel (50, 512, 151, 250, 251, 352) and a measurement device; and 2. The device according to claim 1, wherein measurement pulses (MP) are supplied to the measurement system (70, 80, 90, 170, 180, 190, 270, 280, 370, 380) at time intervals of a measurement interval (T), and the measurement system (70, 80, 90, 170, 180, 190, 270, 280, 370, 380) generates and outputs at least one measurement value (MW, MX, MS, MW1, MW2, MW3) upon the arrival of the measurement pulse (MP).
3. 3. The apparatus of claim 2, wherein the at least one measurement system (70, 80, 90, 170, 180, 190, 270, 280, 370) outputs at least one measurement value (MW, MX, MS, MW1, MW2, MW3) to the data converter (60).
4. 3. The apparatus according to claim 1, wherein the measurement system (370, 380) outputs at least one measurement value (MW1, MW2, MW3) to the calculation unit (64, 66), and the calculation unit (64, 66) calculates an intermediate value (Z, MW) from the at least one measurement value (MW1, MW2, MW3) and outputs it to the data conversion unit (60).
5. 5. The device according to claim 2, wherein the measuring system (70, 80, 90, 370) comprises a data interface (43, 44, 45, 342) connected to a digital measuring device (5, 15, 20X, 30) via a data transmission channel (50, 51, 52, 351, 352).
6. 5. The device according to claim 2, wherein the measurement system comprises a processing interface (143, 144, 145, 243, 244) connected to an incremental encoder (105, 120, 205, 220) or an analog sensor (130) via a signal transmission channel (150, 151, 152, 250, 251).
7. 5. The device according to claim 2, wherein the measurement system (380) comprises a bus interface (344) connected to at least two digital measurement devices (15, 16) via a data transmission channel (352).
8. A method for processing rotation-dependent measurements using an apparatus comprising a data converter (60), a sequence control (46) and an output interface (62), comprising: The method comprises: the data converter (60) is supplied with a series of measurements (MW, MX, MW1, MW2, MW3, Z) at regular time intervals (T) of the measurement interval, these measurements being dependent on the rotation of the shaft (2), and at least one of these measurements being an angle value (MW, MW1, MW3) indicative of the angular position of the shaft (2); In the data converter (60), one revolution of the shaft is divided into n sectors (SEC) and, using one of the angle values (MW, MW1) as a reference angle value, the arriving measurements (MW, MX, MS, MW1, MW2, MW3, Z) are assigned to one sector (SEC) and, depending on the revolution of the shaft (2) for each series of measurements (MW, MX, MS, MW1, MW2, MW3, Z), one result value (EW, EX, ES, EV) is determined accurately for each sector (SEC); and The result values (EW, EX, ES, EV) are output to the output interface (62); A method characterized by:
9. At least one measurement system (70, 80, 90, 170, 180, 190, 270, 370, 380) is provided, the measurement system comprising an interface (43, 44, 45, 143, 145, 243, 244, 342, 344), a transmission channel (50, 512, 151, 250, 251, 352) and a measurement device; and 9. The method of claim 8, wherein measurement pulses (MP) are supplied to a measurement system (70, 80, 90, 170, 180, 190, 270, 280, 370, 380) at time intervals of a measurement interval (T), and the measurement system (70, 80, 90, 170, 180, 190, 270, 280, 370, 380) generates and outputs at least one measurement value (MW, MX, MS, MW1, MW2, MW3) upon the arrival of the measurement pulses (MP).
10. 10. The method of claim 9, wherein at least one measurement system (70, 80, 90, 170, 180, 190, 270, 280, 370) outputs at least one measurement value (MW, MX, MS, MW1, MW2, MW3) to a data converter (60).
11. 11. The method according to claim 9 or 10, characterized in that the measurement system (370, 380) outputs at least one measurement value (MW1, MW2, MW3) to the calculation unit (64, 66), and the calculation unit (64, 66) calculates an intermediate value (Z, MW) from the at least one measurement value (MW1, MW2, MW3) and outputs it to the data conversion unit (60).
12. 12. The method according to claim 9, wherein the measurement system (70, 80, 90, 370) comprises a data interface (43, 44, 45, 342) connected to the digital measurement device (5, 15, 20X, 30) via a data transmission channel (50, 51, 52, 351, 352).
13. 12. The method according to claim 9, wherein the measurement system comprises a processing interface (143, 144, 145, 243, 244) connected to an incremental encoder (105, 120, 205, 220) or an analog sensor (130) via a signal transmission channel (150, 151, 152, 250, 251).
14. 12. The method according to claim 9, wherein the measurement system (380) comprises a bus interface (344) connected to at least two digital measurement devices (15, 16) via a data transmission channel (352).
15. The allocation of measurements (MW, MX, MS, MW1, MW2, MW3, Z) to sectors (SEC) to form result values (EW, EX, ES, EV) is performed in at least one of the following ways: Selecting the last measurement (MW, MX, MS) before the sector change or the first measurement (MW, MX, MS) after the sector change as the result value (EW, EX, ES); The average value of all measurements (MW, MX, MS) within one sector (SEC) is formed as the result value (EW, EX, ES); Calculating a virtual measurement of the angular position at the center of the current sector (SEC) as a result value (EW, EX, ES) from at least two measurements (MW, MX, MS) within the sector (SEC); 15. The method according to claim 8, wherein each of the steps is performed.