Processing machine and processing abnormality judgment method thereof

Abstract

A method for judging processing abnormalities of a processing machine is applied to a processing machine, comprising the following steps: obtaining an acceleration signal corresponding to the acceleration value of the tool end from an accelerometer provided on the tool end; integrating the acceleration signal to generate displacement information; obtaining motor position information of a motor that drives the tool end to move; performing coordinate alignment processing on the displacement information and the motor position information respectively to generate converted displacement information and a position vector described based on the workpiece end coordinate system used by the workpiece end; combining the converted displacement information and the position vector to generate a relative displacement between the tool end and the workpiece end; and judging whether a processing abnormality has occurred in the processing machine based on the relative displacement.

Description

Technical Field

[0001] The present invention relates to a processing machine, and in particular to a processing machine capable of judging processing abnormalities, and a processing abnormality judging method used by the processing machine. Background Art

[0002] Typically, production lines utilize processing machines (e.g., CNC machine tools, robotic arms, etc.) to process target workpieces. Specifically, these machines use internal motors to drive tools (e.g., cutting blades, grippers, etc.) mounted on the tool end to perform processing. By calculating feedback signals from the motor's encoder, the machine can determine the position of the tool end.

[0003] The current problem facing machining centers is that the motor encoder cannot detect vibrations at the tool tip. Therefore, the feedback signal (typically representing the motor angle) cannot be directly equated to the exact position of the tool tip. Specifically, the machine itself can vibrate, or the machine base can vibrate due to external forces. If vibrations cause workpiece processing anomalies during machining, the machine will not be immediately aware of them.

[0004] In the prior art, vibrations from the processing machine can affect the quality of the workpiece, but these vibrations cannot be detected immediately by the machine. Therefore, quality control personnel must wait until the workpiece is finished before filtering out defective products. Consequently, existing processing mechanisms are inefficient, and the quality of the workpieces needs improvement. Summary of the Invention

[0005] The main purpose of the present invention is to provide a processing machine and a processing abnormality judgment method thereof, which can instantly sense vibration and calculate the relative displacement between the tool end and the workpiece end, and judge whether the processing machine has a processing abnormality by monitoring the relative displacement.

[0006] To achieve the above-mentioned objectives, the present invention provides a machining abnormality determination method for a machining machine having a tool end and an opposing workpiece end, wherein a tool is disposed on the tool end and a workpiece is placed on the workpiece end, wherein the tool has a tool end for machining the workpiece. The method comprises:

[0007] a) obtaining an acceleration signal from an accelerometer, wherein the accelerometer is disposed on the tool end and uses an accelerometer coordinate system, the acceleration signal corresponding to a true acceleration value of the tool end;

[0008] b) performing a quadratic integration process on the acceleration signal to generate displacement information;

[0009] c) performing an accelerometer coordinate alignment process to convert the displacement information from the accelerometer coordinate system to a workpiece end coordinate system used by the workpiece end, and generating converted displacement information;

[0010] d) obtaining motor position information, wherein the motor position information is related to at least one motor used to control the tool end and corresponds to a coordinate value of the tool end in a tool end coordinate system;

[0011] e) performing a forward kinematics process on the motor position information to obtain a position vector of the tool end relative to the workpiece end coordinate system;

[0012] f) combining the converted displacement information and the position vector to generate a relative displacement between the tool end and the workpiece end; and

[0013] g) determining whether a machining abnormality occurs in the machining machine based on the relative displacement.

[0014] In order to achieve the above-mentioned object, the processing machine of the present invention comprises:

[0015] a workpiece end for placing a workpiece and using a workpiece end coordinate system;

[0016] a tool end for arranging a tool having a tool end for machining the workpiece and using a tool end coordinate system;

[0017] At least one motor connected to the tool end, controlled to rotate to drive the tool to move and generate motor position information, wherein the motor position information corresponds to a coordinate value of the tool end in the tool end coordinate system;

[0018] an accelerometer, disposed on the tool end, using an accelerometer coordinate system to detect a true acceleration value of the tool end and generate an acceleration signal;

[0019] a driving unit connected to the at least one motor and the accelerometer, for controlling the at least one motor and receiving the motor position information and the acceleration signal; and

[0020] a control unit connected to the drive unit, the control unit being configured to perform a quadratic integration process on the acceleration signal to generate displacement information, and perform an accelerometer coordinate alignment process to transform the displacement information from the accelerometer coordinate system to the workpiece end coordinate system to generate transformed displacement information, and the control unit being configured to perform a forward kinematics process on the motor position information to obtain a position vector of the tool end relative to the workpiece end coordinate system;

[0021] The control unit is configured to combine the converted displacement information and the position vector to generate a relative displacement between the tool end and the workpiece end, and determine whether a processing abnormality occurs in the processing machine based on the relative displacement.

[0022] The technical benefit of this invention over related technologies lies in its ability to effectively detect vibrations in the machining center and accurately calculate the relative displacement between the tool tip and the workpiece. By continuously calculating this relative displacement, the invention enables real-time online monitoring of machining status and offline tracking of machining quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 A first embodiment of a schematic diagram of a processing machine of the present invention;

[0024] Figure 2 A first embodiment of a block diagram of a processing machine according to the present invention;

[0025] Figure 3A A first specific embodiment of a schematic diagram of relative displacement;

[0026] Figure 3B A second specific embodiment of a schematic diagram of relative displacement;

[0027] Figure 4 A first specific embodiment of the flowchart of the determination method of the present invention;

[0028] Figure 5 This is a first specific embodiment of the coordinate alignment diagram of the present invention;

[0029] Figure 6 This is a second specific embodiment of the coordinate alignment diagram of the present invention;

[0030] Figure 7 This is the first specific embodiment of the signal mixing flow chart of the present invention;

[0031] Figure 8 This is the first specific embodiment of the signal mixing flow chart of the present invention;

[0032] Figure 9 This is a second specific embodiment of the signal mixing flow chart of the present invention;

[0033] Figure 10 This is the third specific embodiment of the signal mixing flow chart of the present invention.

[0034] Description of Reference Numerals

[0035] 1…Processing machine

[0036] 10…Control unit

[0037] 101…Time Alignment Module

[0038] 102…Accelerometer coordinate alignment module

[0039] 103…Mechanism coordinate alignment module

[0040] 104…Signal mixing module

[0041] 11…Drive unit

[0042] 12, 13…Motor

[0043] 2…Tool side

[0044] 3…Workpiece end

[0045] 4…Tools

[0046] 41…Tool end

[0047] 5…Accelerometer

[0048] 6…Workpiece

[0049] 71, 81…Mechanism coordinate alignment program

[0050] 72…Low-pass filter

[0051] 73, 82…Quadratic integration procedure

[0052] 74, 83…Accelerometer coordinate alignment program

[0053] 75, 84…High-pass filter

[0054] 91…Tool end coordinate system

[0055] 92…Workpiece end coordinate system

[0056] 93…Accelerometer coordinate system

[0057] 94…Geodetic coordinate system

[0058] 95…Second accelerometer coordinate system

[0059] M1, M2...relative displacement

[0060] V1…First vector

[0061] V2…Second vector

[0062] V3…Third Vector

[0063] S10~S24…judgment steps

[0064] S220~S224…mixing step DETAILED DESCRIPTION

[0065] A preferred embodiment of the present invention is described in detail below with reference to the accompanying drawings.

[0066] The present invention discloses a processing machine (hereinafter referred to as the processing machine) capable of determining machining anomalies. The processing machine can detect unexpected displacement caused by vibration, thereby more accurately calculating the relative displacement between the tool end and the workpiece end. By monitoring this relative displacement, it is possible to effectively determine whether the processing machine has caused machining anomalies due to unexpected vibration during the machining process. Such unexpected vibrations may, for example, be caused by external forces, as well as vibrations caused by insufficient rigidity of the processing machine itself or assembly anomalies, but are not limited to these.

[0067] See also Figure 1 , which is a schematic diagram of a first embodiment of a processing machine according to the present invention. The processing machine according to the present invention can be any type of Computer Numerical Control (CNC) processing machine (e.g., a three-axis, four-axis, or five-axis CNC processing machine), a robotic arm, or a robot, without limitation. Figure 1 The embodiment of the present invention takes a three-axis CNC processing machine 1 as an example, and the technical description of this case is provided in combination with the contents of the specification.

[0068] like Figure 1 As shown, the processing machine 1 mainly has a tool end 2 and an opposite workpiece end 3. A tool 4 is provided on the tool end 2, and the workpiece end 3 is used to place the workpiece 6 to be processed. One side of the tool 4 has a tool end 41 for processing the workpiece 6. The tool 4 can be replaced depending on the processing content. For example, the workpiece 6 may be an aluminum part, and the tool 4 may be the handle of a cutting knife used to cut the aluminum part. For another example, the workpiece 6 may be an electronic component, and the tool 4 may be a gripper. However, the above is only a partial implementation example of the present invention, but it is not limited to this. In the present invention, the tool end 2 and the tool 4 are positioned using the tool end coordinate system, and the workpiece end 3 is positioned using the workpiece end coordinate system, wherein the workpiece end coordinate system is different from the tool end coordinate system (described in detail later).

[0069] One of the technical features of the present invention is that the processing machine 1 further includes at least one accelerometer 5, which is mounted on a movable object on the processing machine 1 to directly detect the object's displacement. When the processing machine 1 vibrates during the processing process, the accelerometer 5 can simultaneously detect the object's unintended displacement caused by the vibration.

[0070] At Figure 1In the embodiment of FIG, a processing machine 1 drives a tool 4 by moving a tool end 2, thereby machining a workpiece 6 placed on a platform at a workpiece end 3 with a tool tip 41. In this embodiment, an accelerometer 5 is mounted on the tool end 2. The accelerometer 5 is designed to detect both the intended displacement of the tool tip 41 and unintended displacement caused by vibration. The accelerometer 5 outputs acceleration signals representing these displacements. Therefore, the closer the accelerometer 5 is positioned on the tool end 2, the better.

[0071] In this embodiment, the accelerometer 5 is positioned using an accelerometer coordinate system. Furthermore, the accelerometer 5 is used to continuously detect the actual acceleration value of the tool end 41 during the processing of the processing machine 1 and generate a corresponding acceleration signal.

[0072] As described above, the accelerometer 5 can detect both expected and unexpected displacements of a movable object on the processing machine 1 (e.g., the tool end 2). The processing machine 1 of the present invention calculates the relative position between the tool end 41 and the workpiece end 3 based on the acceleration signal output by the accelerometer 5. This can also account for unexpected displacements caused by vibration, resulting in more accurate calculations and, in turn, improved processing yield. Therefore, any movable object on the processing machine 1 can be equipped with an accelerometer 5 to detect its vibration information.

[0073] Furthermore, if multiple tools 4 are mounted on the tool end 2, or if the tool 4 has multiple tool tips 41, an accelerometer 5 may be provided for each tool 4 / tool tip 41. By providing multiple accelerometers 5, the unexpected displacement of each tool 4 / tool tip 41 caused by vibration can be detected separately, thereby making the calculation results more accurate.

[0074] On the other hand, for objects on the processing machine 1 that cannot move but are still affected by vibration (for example, the object is a platform placed on a table that may be bumped, or vibrations generated by the workpiece end itself), an accelerometer 5 can also be set to detect unexpected displacements of the object due to the influence of external vibrations.

[0075] For ease of understanding, Figure 1 In the description, only a single accelerometer 5 provided on the tool end 2 is taken as an example for description, but the number of accelerometers 5 is not limited to one, and the setting position of the accelerometer 5 is not limited to being provided on the tool end 2.

[0076] Please also see Figure 1 and Figure 2 ,in Figure 2 FIG. 1 is a block diagram of a processing machine according to the present invention. Figure 2As shown, the processing machine 1 further includes a control unit 10, a drive unit 11, and a motor 12. The control unit 10 is connected to the drive unit 11 and issues motor commands to the drive unit 11. The drive unit 11 is connected to the motor 12 and controls the motor 12 via the motor commands. The motor 12 is connected to the tool end 2 and rotates based on the motor commands, thereby moving the tool end 2 and the tool 4 mounted thereon, thereby implementing the processing program via the tool end 41.

[0077] Specifically, in this embodiment, the processing machine 1 is primarily configured with at least one motor 12. The movement of the tool 4 is achieved through the corresponding action generated by the at least one motor 12 under control. It is worth noting that the number of motors 12 is not limited to one. In other embodiments, the processing machine 1 may utilize multiple motors 12 connected to the drive unit 11 and the tool end 2, thereby enabling the movement of the tool end 2 and the tool 4 through the action of multiple motors 12.

[0078] If the processing machine 1 includes a movable workpiece end 3, the processing machine 1 may also include one or more motors 13 connected to the drive unit 11 and the workpiece end 3. In this embodiment, the control unit 10 issues motor commands to the drive unit 11, which then controls the motors 13 based on these commands. The motors 13 rotate according to the commands, thereby moving the workpiece end 3. In this way, the processing machine 1 implements the processing program through the tool tip 41 and the workpiece end 3.

[0079] At Figure 2 In the embodiment of the present invention, the drive unit 11 is connected to the motor 12 and the accelerometer 5 to control the motor 12 and receive motor position information related to the position of the motor 12 and the acceleration signal output by the accelerometer 5. It is worth mentioning that the motor 12 rotates based on the motor command and generates motor position information (for example, generated by a motor encoder on the motor 12), and the processing machine 1 moves the tool end 41 to the desired position by rotating the motor 12. Therefore, the motor position information can correspond to the coordinate value of the tool end 41 in the tool end coordinate system. Without considering unexpected vibrations, the motor position information can be used to directly represent the position of the tool end 41 in the tool end coordinate system.

[0080] One of the technical features of the present invention is that the control unit 10 calculates the relative displacement between the tool end 41 and the workpiece end 3 through the motor position information and the acceleration signal, and this relative displacement includes the expected displacement of the tool end 41 based on the rotation of the motor 12, and the unexpected displacement caused by the unexpected vibration of the tool end 41.

[0081] See Figure 3A and Figure 3B, which are respectively the first specific embodiment and the second specific embodiment of the schematic diagram of relative displacement.

[0082] As described above, the present invention uses the control unit 10 to continuously calculate the relative displacement between the tool tip 41 and the workpiece end 3 during the machining process of the machining machine 1 using motor position information and acceleration signals. This relative displacement not only represents the expected displacement of the tool tip 41 due to machining requirements, but also represents unintended displacement of the tool tip 41 due to vibration.

[0083] like Figure 3A As shown, when the processing machine 1 is operating normally, the relative displacement M1 between the tool end 41 and the workpiece end 3 will be normal. Figure 3B As shown, when the processing machine 1 generates unexpected vibration due to internal or external factors, the relative displacement M2 between the tool end 41 and the workpiece end 3 will have an instantaneous extreme value (for example, the processing machine 1 is hit by an external force), causing the relative displacement M2 to exceed the threshold value.

[0084] If the relative displacement M2 exceeds the threshold, the workpiece 6 being processed may be defective, and therefore the processing machine 1 should be shut down immediately. In one embodiment, the control unit 10 can directly shut down the processing machine 1 upon determining that the relative displacement M2 exceeds the threshold. In another embodiment, the control unit 10 can generate a control signal upon determining that the relative displacement M2 exceeds the threshold, and send the control signal to the inverter (or motor driver) to stop the motor of the processing machine 1. By ceasing processing of potentially defective products, processing time can be effectively saved. This achieves the purpose of online, real-time monitoring of the processing status in this case.

[0085] Furthermore, each workpiece 6 on the production line is typically individually numbered. The control unit 10 can record the number and processing time of each workpiece 6, and also record the relative displacements M1 and M2 during the processing. If quality control personnel discover a defective product during finished product inspection, they can use the defective product number and processing time to query the corresponding relative displacements M1 and M2, thereby determining the cause of the defect. By subsequently tracking the processing status, the purpose of offline tracking of processing quality can be achieved.

[0086] Back to Figure 2In one embodiment, the control unit 10 may be a processor such as a central processing unit (CPU), a microcontroller unit (MCU), a graphics processing unit (GPU), or a field programmable gate array (FPGA). In another embodiment, the control unit 10 may be implemented by an independent personal computer (PC), an industrial PC (IPC), a cabinet server, a cloud server, a laptop computer, etc., and connected to the drive unit 11 of the processing machine 1 via a network or a transmission port, but is not limited thereto.

[0087] In one embodiment, the control unit 10 is used to perform temporal processing and spatial processing on the motor position information and the acceleration signal, and mix the processed signals to generate the following: Figure 3A 、 Figure 3B The relative displacements M1 and M2 are shown.

[0088] Specifically, the control unit 10 records computer executable program code. When the control unit 10 executes the computer executable program code, the various main functions of the control unit 10 can be realized, including time processing of motor position information and acceleration signals, spatial processing of motor position information and acceleration signals, mixing of processed signals, etc.

[0089] Based on the above functions that can be realized by the control unit 10, the computer executable program code may include multiple virtual modules composed of software (for example, multiple sub-programs in the computer executable program code), each of which is used to execute one specific function of the control unit 10. Figure 2 In the embodiment, the control unit 10 logically divides the computer-executable program code into multiple virtual modules based on the desired functionality, including a time alignment module 101, an accelerometer coordinate alignment module 102, a mechanism coordinate alignment module 103, and a signal mixing module 104. However, the above is only one specific embodiment of the present invention, and the control unit 10 is not limited to the aforementioned modules 101-104.

[0090] Please also see Figures 1 to 4 ,in Figure 4This is a flowchart of the first embodiment of the determination method of the present invention. The primary purpose of the present invention is to continuously calculate the relative displacement of the tool tip 41 relative to the workpiece end 3 during the machining process of the machining machine 1, thereby determining whether the machining process has experienced an abnormality due to unexpected vibration. To this end, the machining machine 1 first requires that the control unit 10 continuously obtain acceleration signals from the accelerometer 5 (step S10) and motor position information (step S12) during the machining process. Steps S10 and S12 are not executed sequentially.

[0091] In this embodiment, the accelerometer 5 is mounted directly on the tool end 2. Therefore, the acceleration signal output by the accelerometer 5 can be correlated to the actual acceleration value of the tool end 41. The motor position information is generated based on the motor angle of the motor 12 used to control the tool end 2 and can be correlated to the coordinate value of the tool end 41 in the tool end coordinate system.

[0092] In one embodiment, the motor 12 is a sensor-based motor. The drive unit 11 controls the rotation of the motor 12 based on motor commands from the control unit 10. The motor 12 also provides signal feedback via a motor encoder (not shown) to provide motor position information to the drive unit 11. In this embodiment, the motor position information is the encoder signal, which can be mapped to the actual motor angle.

[0093] In another embodiment, the drive unit 11 not only controls the rotation of the motor 12 according to the motor command, but also inputs the motor command into a virtual motor model (not shown) constructed from mathematical formulas. In this embodiment, the virtual motor model simulates the function of a motor encoder, calculating the actual motor angle of the motor 12 from the motor command and generating a corresponding feedback signal as the motor position information.

[0094] However, the above are only some specific implementation examples of the present invention, and are not limited thereto.

[0095] After step S10 and step S12, the control unit 10 performs time processing on the motor position information and the acceleration signal through the time alignment module 10 (step S14), so that the motor position information and the acceleration signal are synchronized in time and can be used together to describe the relative position relationship between the tool end 41 and the workpiece end 3 at a specific time point.

[0096] In another embodiment, the time alignment module 10 may be implemented using external time alignment technology, such as using EtherCAT synchronization signals to achieve time synchronization. In this embodiment, the time alignment module 10 is not necessarily present in the control unit 10. That is, the motor position information and acceleration signals received by the control unit 10 are already synchronized in time, so the time processing is not required.

[0097] Next, the control unit 10 performs a secondary integration process on the acceleration signal via the accelerometer coordinate alignment module 101 to generate displacement information (step S16). Specifically, the control unit 10 first performs a first integration process on the acceleration signal to convert the acceleration signal into a velocity signal, and then performs a second integration process on the velocity signal to obtain displacement information.

[0098] As previously mentioned, the accelerometer 5 is positioned using the accelerometer coordinate system by default. Therefore, the displacement information is described based on the accelerometer coordinate system. After step S16, the accelerometer coordinate alignment module 101 performs accelerometer coordinate alignment processing on the displacement information, converting it from the accelerometer coordinate system to the workpiece end coordinate system used by the workpiece end 3 and generating the corresponding converted displacement information (step S18).

[0099] Specifically, the displacement information describes the position of the tool end 41 based on the accelerometer coordinate system, while the converted displacement information describes the position of the tool end 41 based on the workpiece end coordinate system. The present invention converts different information to the same coordinate system through alignment processing, so that these information can be mixed to accurately describe the position of the tool end 41. Figure 4 In the embodiment, all information is converted into the workpiece end coordinate system as an example, but the present invention is not limited thereto.

[0100] On the other hand, the control unit 10 performs a mechanism alignment process on the motor position information through the mechanism coordinate alignment module 103 to obtain the position vector of the tool end 41 relative to the workpiece end coordinate system (step S20). In one embodiment, the mechanism alignment process is a forward kinematics process. In this embodiment, the mechanism coordinate alignment module 103 performs a forward kinematics process on the motor position information based on the workpiece end coordinate system, and can convert the coordinate information of the motor 12 in the axial space (i.e., the motor position information) into a vector relative to the workpiece end coordinate system. Moreover, this vector can describe the position of the tool end 41 controlled by the motor 12 based on the workpiece end coordinate system.

[0101] Since the acceleration signal generates displacement information after quadratic integration, representing the position of the tool end 41, the control unit 10 only needs to perform coordinate system conversion on the displacement information to complete the alignment process. The motor position information represents the rotation angle of the motor 12, so it is necessary to first convert the rotation angle to a position in three-dimensional space through forward kinematics processing before performing the coordinate system conversion.

[0102] It is worth mentioning that step S18 and step S20 do not have an execution order relationship. In one embodiment, the control unit 10 may first execute step S18 to obtain the converted displacement information, and then execute step S20 to obtain the position vector. In another embodiment, the control unit 10 may first execute step S20 to obtain the position vector, and then execute step S18 to obtain the converted displacement information. In yet another embodiment, the control unit 10 may execute step S18 and step S20 simultaneously through multiplexing, instead of in sequence. Figure 4 The process sequence shown is limited.

[0103] After steps S18 and S20, the control unit 10 further executes a signal mixing process via the signal mixing module 104 to obtain the relative displacement between the tool tip 41 and the workpiece end 3 (step S22). Specifically, the signal mixing module 104 combines the converted displacement information with the position vector to generate the relative displacement between the tool tip 41 and the workpiece end 3.

[0104] Based on the generated relative displacement, the control unit 10 can determine whether a processing abnormality occurs in the processing machine 1 (step S24). It is worth mentioning that the control unit 10 continuously executes the steps S10 to S24 during the processing of the processing machine 1 to continuously monitor and calculate the relative displacement between the tool end 41 and the workpiece end 3 (i.e., generate the relative displacement between the tool end 41 and the workpiece end 3). Figure 3A 、 Figure 3B ), thereby determining whether the processing machine 1 has a processing abnormality due to unexpected vibration.

[0105] In one embodiment, the accelerometer coordinate alignment module 102 in step S18 primarily performs a Proper Euler Angles conversion on the displacement information based on the workpiece-end coordinate system to process the displacement information and generate converted displacement information. The converted displacement information is described based on the workpiece-end coordinate system and can be aligned with the information on the workpiece end 3.

[0106] The Euler angle conversion process can, for example, multiply the displacement information by the ZYX Euler angle conversion matrix. That is, the displacement information is first rotated by C degrees with respect to the Z axis of the accelerometer coordinate system, then rotated by B degrees with respect to the Y axis, and finally rotated by A degrees with respect to the X axis. The angles are set based on the known difference between the accelerometer coordinate system and the workpiece end coordinate system. The ZYX Euler angle conversion matrix is as follows:

[0107]

[0108] Where R is the ZYX Euler angle transformation matrix.

[0109] In one embodiment, the accelerometer coordinate alignment module 102 may calculate the converted displacement information based on the following formula:

[0110] U=RV.

[0111] Among them, R is the ZYX Euler angle transformation matrix, V is the displacement information (for example, the coordinate value (X V ,Y V ,Z V ), or the displacement on the three axes, U is the displacement information after conversion (for example, the coordinate value (X U ,Y U ,Z U ), or displacements along three axes. For example, if the displacement information V is displacement along three axes, the displacements along the first coordinate system (e.g., 1 μm, 2 μm, 3 μm) can be converted into displacements along the second coordinate system (e.g., 3.096 μm, 0.618 μm, 2.008 μm) by using a Euler angle conversion matrix with Z-axis 30 degrees, Y-axis 40 degrees, and X-axis 50 degrees.

[0112] In one embodiment, the forward kinematics processing performed by the mechanism coordinate alignment module 103 in step S20 primarily involves calculating motor position information using a Denavit-Hartenberg Parameters (DH) table based on the workpiece-end coordinate system to generate a position vector of the tool end 41 relative to the workpiece-end coordinate system. The DH table may, for example, include the following three formulas:

[0113]

[0114]

[0115]

[0116] in, is the transformation matrix from the i-1th axis to the i-th axis, B is the source base coordinate system (such as the tool end coordinate system), E is the endpoint coordinate system (such as the workpiece end coordinate system), R is the rotation matrix, and t is the translation matrix. The vector from the base coordinate system to the endpoint of the i-th axis.

[0117] Specifically, the above-mentioned forward kinematics processing and DH table are commonly used technical means in the field of coordinate transformation, and for the sake of brevity of the description, they will not be described in detail here.

[0118] Please also see Figure 1 、 Figure 2 、 Figure 4 and Figure 5 ,in Figure 5 This is the first specific embodiment of the coordinate alignment diagram of the present invention. Figure 5 In the embodiment, the tool end 2 and the tool 4 thereon both use a tool end coordinate system 91 , the workpiece end 3 uses a workpiece end coordinate system 92 , and the accelerometer 5 uses an accelerometer coordinate system 93 .

[0119] In this embodiment, the control unit 10 uses the workpiece-end coordinate system 92 as the base coordinate system for all position-related signals. Specifically, the control unit 10 converts the motor position information describing the coordinate values of the tool tip 41 based on the tool-end coordinate system 91 into a first vector V1 describing the relative position of the tool tip 41 based on the workpiece-end coordinate system 92. Furthermore, the control unit 10 converts the displacement information describing the displacement state of the tool tip 41 based on the accelerometer coordinate system 93 into converted displacement information describing the displacement state of the tool tip 41 based on the workpiece-end coordinate system 92. The first vector V1 refers to the coordinate position of the tool tip 41 relative to the origin (0, 0, 0) of the workpiece-end coordinate system 92.

[0120] When all position-related information is described in the same basic coordinate system (the workpiece end coordinate system 92 in this embodiment), the control unit 10 can calculate the position-related information (for example, by executing Figure 4 The hybrid process of step S22 is performed to generate the relative displacement between the tool end 41 and the workpiece end 3.

[0121] It is worth mentioning that Figure 1 As shown, if the workpiece end 3 of the processing machine 1 is movable, the processing machine 1 may further include a motor 13 connected to the driving unit 11 and the workpiece end 3 .

[0122] If the workpiece end 3 is movable, the workpiece 6 will also move with the workpiece end 3. In this embodiment, the control unit 10 needs to calculate the first vector V1 that describes the position of the tool tip 41 based on the workpiece end coordinate system 92, the converted displacement information that describes the displacement state of the tool tip 41 based on the workpiece end coordinate system 92, and another vector that describes the position of the workpiece 6 based on the workpiece end coordinate system 92. Furthermore, the relative displacement between the tool tip 41 and the workpiece end 3 is calculated based on the first vector V1, the converted displacement information, and the other vector.

[0123] However, since the workpiece 6 is placed on the workpiece 3, the position information of the workpiece 6 is originally described based on the workpiece end coordinate system 92. In other words, the other vector describing the position of the workpiece 6 based on the workpiece end coordinate system 92 is zero. In other words, if the workpiece end coordinate system 92 is used as the base coordinate system, even if the processing machine 1 uses a movable workpiece end 3, the control unit 10 only needs to obtain the first vector V1 and the converted displacement information to calculate the relative displacement between the tool tip 41 and the workpiece end 3.

[0124] Please also see Figure 1 、 Figure 2 、 Figure 4 and Figure 6 ,in Figure 6 This is the second specific embodiment of the coordinate alignment diagram of the present invention. Figure 6 In this embodiment, the control unit 10 uses the world coordinate system 94 as the base coordinate system for all position-related signals. In this embodiment, the control unit 10 converts motor position information describing the coordinates of the tool end 41 based on the tool end coordinate system 91 into a second vector V2 describing the relative position of the tool end 41 based on the world coordinate system 94. Furthermore, the control unit 10 converts displacement information describing the displacement state of the tool end 41 based on the accelerometer coordinate system 93 into converted displacement information describing the displacement state of the tool end 41 based on the world coordinate system 94.

[0125] At Figure 6 In the embodiment of the present invention, the processing machine 1 does not use the workpiece end coordinate system 92 as the basic coordinate system, so Figure 4 In step S18, the control unit 10 processes the displacement information generated by the accelerometer 5 based on the earth coordinate system 94 to generate converted displacement information described based on the earth coordinate system 94. Figure 4 In step S20 , the control unit 10 performs forward kinematic processing on the motor position information based on the earth coordinate system 94 to obtain a first vector V1 of the tool end 41 relative to the earth coordinate system 94 .

[0126] Moreover, since the processing machine 1 is not based on the workpiece end coordinate system 92, if the workpiece end 3 can move, the control unit 10 also needs to obtain the motor position information of the motor 13 used to control the workpiece end 3, and perform forward kinematic processing on the motor position information based on the geodetic coordinate system 94 to obtain a third vector V3 that describes the position of the workpiece end 3 based on the geodetic coordinate system 94.

[0127] By using the second vector V2 , the third vector V3 and the converted displacement information described in the earth coordinate system 94 , the control unit 10 can accurately calculate the relative displacement between the tool end 41 and the workpiece end 3 .

[0128] In one embodiment, if the processing machine 1 includes a movable workpiece end 3, the processing machine 1 may further include a second accelerometer 51 disposed on the workpiece end 3. The second accelerometer 51 utilizes a second accelerometer coordinate system 95 and obtains a second acceleration value during the processing of the processing machine 1, wherein the second acceleration value corresponds to the actual acceleration value of the workpiece end 3.

[0129] In this embodiment, the control unit 10 is Figure 4 In step S10, the second acceleration value needs to be obtained from the second accelerometer 51 at the same time. In step S16, the second acceleration value needs to be subjected to the secondary integration procedure to generate second displacement information. In step S18, the accelerometer coordinate alignment process needs to be performed on the second displacement information to convert the second displacement information from the second accelerometer coordinate system 95 to the base coordinate system (i.e., the workpiece end coordinate system 92 or the earth coordinate system 94) to generate second converted displacement information.

[0130] Furthermore, in this embodiment, the control unit 10 Figure 4 In step S22, the second converted displacement information must also be used as the basis for calculating the relative displacement. This way, the relative displacement calculated by the control unit 10 includes not only the unintended displacement caused by vibration of the tool tip 41, but also the unintended displacement caused by vibration of the workpiece end 3. This makes the relative displacement calculated by the control unit 10 more accurate.

[0131] Please also refer to Figure 1 、 Figure 2 、 Figure 4 and Figure 7 ,in Figure 7 This is the first specific embodiment of the signal mixing flow chart of the present invention. Figure 7 The control unit 10 is used to illustrate Figure 4 In step S22 , a signal mixing process is performed to obtain the relative displacement between the tool end 41 and the workpiece end 3 .

[0132] like Figure 7 As shown, when executing the signal mixing process, the control unit 10 first obtains the converted displacement information through the signal mixing module 104 (step S220) and obtains the position vector (step S222). The control unit 10 then processes the converted displacement information based on a first weight value and the position vector based on a second weight value through the signal mixing module 104, and then combines the processed converted displacement information and the processed position vector to generate the relative displacement (step S224). The high-frequency portion of the first weight value is greater than the low-frequency portion, while the low-frequency portion of the second weight value is greater than the high-frequency portion.

[0133] Specifically, the present invention sets the accelerometer 5 on the tool end 2 to directly detect the acceleration signal of the tool end 41. Therefore, as long as the displacement information is calculated based on the acceleration signal and then converted to the workpiece end coordinate system, the relative displacement between the tool end 41 and the workpiece end 3 can be directly represented by the converted displacement information.

[0134] However, the accelerometer 5 outputs the acceleration signal in the form of voltage, which often generates a bias. This means that even if the tool end 2 does not move, the accelerometer 5 still outputs a signal (i.e., voltage). This can lead to misjudgment by the control unit 10. Therefore, the reliability of the low-frequency portion of the acceleration signal output by the accelerometer 5 is low.

[0135] On the other hand, since the motor position information cannot reflect the high-frequency vibration of the tool end 41, an accelerometer is required to be provided at the tool end 41 as an auxiliary.

[0136] The signal mixing module 104 of the present invention reduces the low-frequency components of the converted displacement information (from the accelerometer 5) by setting the first weight value, and reduces the high-frequency components of the position vector (from the motor 12) by setting the second weight value. Through the processing of the first and second weight values, the relative displacement calculated by the control unit 10 will primarily be composed of the high-frequency portion of the converted displacement information and the low-frequency portion of the position vector. This avoids the problem caused by the low-frequency bias of the accelerometer 5 and the motor position information of the motor 12 being unable to predict unexpected vibrations at the end point.

[0137] The following combination Figure 8 、 Figure 9 and Figure 10 The following describes the related embodiments of processing the high-frequency signal and the low-frequency signal.

[0138] Please also refer to Figure 1 、 Figure 2 、 Figure 4 、 Figure 7 and Figure 8 ,in Figure 8 This is the first specific embodiment of the signal mixing flow chart of the present invention.

[0139] At Figure 8 In the embodiment, the control unit 10 performs a mechanism coordinate alignment procedure 71 on the motor position information to generate a position vector describing the coordinate value of the tool end 41 based on the workpiece end coordinate system. Next, the control unit 10 uses a low-pass filter 72 to filter the position vector Filter to produce low-frequency position vectors

[0140] Furthermore, the control unit 10 performs a secondary integration procedure 73 on the acceleration signal output by the accelerometer 5 to generate displacement information describing the position of the tool end 41 based on the tool end coordinate system. Furthermore, the control unit 10 processes the displacement information Perform the accelerometer coordinate alignment procedure 74 to generate the transformed displacement information describing the position of the tool end 41 based on the workpiece end coordinate system. Furthermore, the control unit 10 further filters the converted displacement information through a high-pass filter 75 or a band-pass filter. Filtering to generate high-frequency displacement information

[0141] Finally, the control unit 10 converts the low-frequency position vector and high-frequency displacement information Add to generate the relative displacement between the tool end 41 and the workpiece end 3

[0142] At Figure 8 In the embodiment, the relative displacement The high-frequency portion of the signal is obtained from the acceleration signal output by the accelerometer 5, while the low-frequency portion is obtained from the motor position information of the motor 12. This effectively avoids problems caused by the low-frequency bias of the accelerometer 5 and the inability of the motor position information of the motor 12 to predict unexpected vibrations at the transmission end.

[0143] It is worth mentioning that if the processing machine 1 is provided with multiple accelerometers (e.g. Figure 6For example, if the accelerometer 5 and the second accelerometer 51 are shown, the control unit 10 similarly performs a secondary integration process 73 and an accelerometer coordinate alignment process 74 on the second acceleration signal output by the second accelerometer 51 to generate second converted displacement information. The second converted displacement information is then filtered through a high-pass filter 75 or a bandpass filter to generate second high-frequency displacement information. In this embodiment, the control unit 10 adds the low-frequency position vector, the high-frequency displacement information, and the second high-frequency displacement information to generate the relative displacement between the tool tip 41 and the workpiece end 3.

[0144] It is worth mentioning that in other embodiments, the control unit 10 may first subtract the displacement information converted by the accelerometer coordinate alignment program 74 from the second converted displacement information, and then filter the added information through a high-pass filter 75 or a band-pass filter instead of using Figure 8 The processing order shown is limited.

[0145] Please also see Figure 1 、 Figure 2 、 Figure 4 、 Figure 7 、 Figure 8 and Figure 9 ,in Figure 9 This is the second specific embodiment of the signal mixing flow chart of the present invention.

[0146] At Figure 9 In the embodiment, the control unit 10 performs a mechanism coordinate alignment procedure 71 on the motor position information to generate a position vector describing the coordinate value of the tool end 41 based on the workpiece end coordinate system. Next, the control unit 10 uses a low-pass filter 72 to filter the position vector Filter to produce a low-frequency position vector

[0147] and Figure 8 The difference between the embodiments is that Figure 9 The processing machine 1 may be provided with a plurality of accelerometers, for example, including a accelerometer for detecting the actual acceleration of the tool end 41. The first accelerometer, and the real acceleration of the workpiece end 3 The second accelerometer.

[0148] In this embodiment, the control unit 10 controls the first acceleration signal output by the first accelerometer. A second integration process 73 is performed to generate first displacement information describing the position of the tool end 41 based on the tool end coordinate system. Furthermore, the control unit 10 processes the first displacement information The accelerometer coordinate alignment procedure 74 is performed to generate first transformed displacement information describing the position of the tool end 41 based on the workpiece end coordinate system.

[0149] On the other hand, the control unit 10 controls the second acceleration signal output by the second accelerometer A secondary integration process 73 is performed to generate second displacement information describing the position of the workpiece 6 based on the workpiece end coordinate system. Furthermore, the control unit 10 processes the second displacement information Perform the accelerometer coordinate alignment procedure 74 to generate the second transformed displacement information aligned with the workpiece end coordinate system. It is worth mentioning that the position of the workpiece 6 is originally described based on the workpiece end coordinate system. Therefore, in this embodiment, the control unit 10 can directly output the second displacement information after the secondary integration procedure 73. There is no need to execute the accelerometer coordinate alignment procedure 74 .

[0150] Next, the control unit 10 converts the first displacement information With the second converted displacement information Subtract to generate the initial relative displacement between the tool end 41 and the workpiece end 3 Then the preliminary relative displacement is filtered by a high-pass filter 75 or a band-pass filter. Filtering to generate high-frequency relative displacement

[0151] Finally, the control unit 10 converts the low-frequency position vector Relative displacement with high frequency Add to generate the relative displacement between the tool end 41 and the workpiece end 3

[0152] At Figure 9 In the embodiment, the relative displacement The high-frequency portion of the signal is derived from the acceleration signals output by the two accelerometers, while the low-frequency portion is derived from the motor position information of motor 12. This effectively avoids problems caused by the low-frequency bias of the accelerometers and the inability of motor position information from motor 12 to predict unexpected vibrations at the transmission end.

[0153] Please also refer to Figure 1 、 Figure 2 、 Figure 4 and Figure 10 ,in Figure 10 This is the third specific embodiment of the signal mixing flow chart of the present invention.

[0154] At Figure 10In the embodiment, the control unit 10 performs a mechanism coordinate alignment procedure 81 on the motor position information to generate a position vector describing the coordinate value of the tool end 41 based on the workpiece end coordinate system. On the other hand, the control unit 10

[0155] The control unit 10 performs a secondary integration process 82 on the acceleration signal output by the accelerometer 5 to generate displacement information corresponding to the position of the tool end 41 based on the tool end coordinate system. Furthermore, the control unit 10 processes the displacement information Perform the accelerometer coordinate alignment procedure 83 to generate the transformed displacement information describing the position of the tool end 41 based on the workpiece end coordinate system.

[0156] In this embodiment, the control unit 10 then converts the converted displacement information With position vector Subtract to produce a mixed vector Then, the control unit 10 filters the mixed vector by a high-pass filter 84 or a band-pass filter. Filter to generate high-frequency mixed vectors Finally, the control unit 10 converts the high frequency mixed vector With the position vector (i.e., the position vector ) are added to generate the relative displacement between the tool end 41 and the workpiece end 3

[0157] and Figure 8 and Figure 9 Similar to the embodiment, Figure 10 The relative displacement in The high-frequency portion is obtained from the acceleration signal output by the accelerometer 5, and the low-frequency portion is obtained from the motor position information of the motor 12. Therefore, the problem caused by the low-frequency bias of the accelerometer 5 and the motor position information of the motor 12 being unable to predict the unexpected vibration of the transmission end can also be avoided.

[0158] And, with Figure 9 Similar to the embodiment of the present invention, when the processing machine 1 is provided with multiple accelerometers, the processing machine 1 can also be based on Figure 10 The relative displacement between the tool end 41 and the workpiece end 3 is calculated by the calculation method shown in FIG. Therefore, I will not go into details here.

[0159] Through the technical solution of this invention, the control unit can accurately calculate the relative displacement of the tool tip relative to the workpiece end using the output signals of the motor and accelerometer. This relative displacement includes both the expected displacement of the tool tip during normal operation and the unintended displacement caused by vibration. Consequently, this invention achieves the beneficial effects of both online and real-time monitoring of machining status and offline tracking of machining quality.

[0160] The above description is only a preferred embodiment of the present invention, and does not limit the claims of the present invention. Therefore, all equivalent changes made by applying the content of the present invention are similarly included in the scope of the present invention and are hereby stated.

Claims

1. A method for determining machining abnormalities in a machining machine, the method being applied to a machining machine having a tool end and an opposing workpiece end, the tool end being provided with a tool, the workpiece end being provided with a workpiece, the tool having a tool end for machining the workpiece, the method comprising: a) obtaining an acceleration signal from an accelerometer, wherein the accelerometer is disposed on the tool end and uses an accelerometer coordinate system, the acceleration signal corresponding to a true acceleration value of the tool end; b) performing a secondary integration procedure on the acceleration signal to generate displacement information; c) performing accelerometer coordinate alignment processing to convert the displacement information from the accelerometer coordinate system to the workpiece end coordinate system used by the workpiece end, and generating converted displacement information; d) obtaining motor position information, wherein the motor position information is related to at least one motor used to control the tool end and corresponds to a coordinate value of the tool end in a tool end coordinate system; e) performing forward kinematic processing on the motor position information to obtain a position vector of the tool end relative to the workpiece end coordinate system; f) combining the converted displacement information and the position vector to generate a relative displacement between the tool end and the workpiece end; and g) determining whether a machining abnormality occurs in the machining machine based on the relative displacement.

2. The machining abnormality determination method according to claim 1, wherein the step f) comprises: f11) obtaining the converted displacement information; f12) obtaining the position vector; f13) processing the converted displacement information based on a first weight value, and processing the position vector based on a second weight value, wherein a high-frequency portion of the first weight value is greater than a low-frequency portion, and a low-frequency portion of the second weight value is greater than a high-frequency portion; and f14) Combining the processed converted displacement information and the processed position vector to generate the relative displacement.

3. The machining abnormality determination method according to claim 1, wherein the step f) comprises: f21) obtaining the converted displacement information and filtering the converted displacement information through a high-pass filter to generate high-frequency displacement information; f22) obtaining the position vector and filtering the position vector through a low-pass filter to generate a low-frequency position vector; and f23) Combining the high-frequency displacement information and the low-frequency position vector to generate the relative displacement.

4. The machining abnormality determination method according to claim 1, wherein the step f) comprises: f31) obtaining the converted displacement information and the position vector f32) subtracting the converted displacement information from the position vector to generate a mixed vector; f33) filtering the mixed vector through a high-pass filter to generate a high-frequency mixed vector; and f34) Combining the high-frequency mixed vector and the position vector to generate the relative displacement.

5. The method for determining machining abnormalities according to claim 1 , wherein the machining machine comprises a second accelerometer disposed on the workpiece end, the second accelerometer using a second accelerometer coordinate system, and before step f), further comprising: f01) obtaining a second acceleration signal from the second accelerometer, wherein the second acceleration signal corresponds to a true acceleration value of the workpiece end; f02) performing the secondary integration procedure on the second acceleration signal to generate second displacement information; and f03) performing the accelerometer coordinate alignment process to transform the second displacement information from the second accelerometer coordinate system to the workpiece end coordinate system, and generating second transformed displacement information; The step f) combines the converted displacement information, the position vector and the second converted displacement information to generate the relative displacement.

6. A processing machine comprising: The workpiece end is used to place the workpiece and use the workpiece end coordinate system; a tool end for arranging a tool having a tool end for machining the workpiece and using a tool end coordinate system; At least one motor connected to the tool end, controlled to rotate to move the tool and generate motor position information, wherein the motor position information corresponds to the coordinate value of the tool end in the tool end coordinate system; an accelerometer, disposed on the tool end, detecting a true acceleration value of the tool end using an accelerometer coordinate system and generating an acceleration signal; a driving unit connected to the at least one motor and the accelerometer, for controlling the at least one motor and receiving the motor position information and the acceleration signal; and a control unit connected to the drive unit, the control unit being configured to perform a quadratic integration procedure on the acceleration signal to generate displacement information, and perform an accelerometer coordinate alignment process to transform the displacement information from the accelerometer coordinate system to the workpiece end coordinate system to generate transformed displacement information, and the control unit being configured to perform a forward kinematics process on the motor position information to obtain a position vector of the tool end relative to the workpiece end coordinate system; The control unit is configured to combine the converted displacement information and the position vector to generate a relative displacement between the tool end and the workpiece end, and determine whether a processing abnormality occurs in the processing machine based on the relative displacement.

7. The processing machine according to claim 6, wherein the accelerometer coordinate alignment program is based on the workpiece end coordinate system to perform a Euler angle conversion program on the displacement information to generate the converted displacement information, and the forward kinematics processing is based on the workpiece end coordinate system to use the DH table to calculate the motor position information to generate the position vector.

8. The processing machine according to claim 6, wherein the control unit is configured to filter the converted displacement information through a high-pass filter to generate high-frequency displacement information, filter the position vector through a low-pass filter to generate a low-frequency position vector, and then combine the high-frequency displacement information and the low-frequency position vector to generate the relative displacement amount.

9. The processing machine according to claim 6, wherein the control unit is configured to subtract the converted displacement information from the position vector to generate a mixed vector, filter the mixed vector through a high-pass filter to generate a high-frequency mixed vector, and then combine the high-frequency mixed vector and the position vector to generate the relative displacement.

10. The processing machine according to claim 6, further comprising: a second accelerometer, disposed on the workpiece end, detecting a true acceleration value of the workpiece end using a second accelerometer coordinate system and generating a second acceleration signal; The control unit is configured to perform the secondary integration procedure on the second acceleration signal to generate second displacement information, and perform the accelerometer coordinate alignment process to transform the second displacement information from the second accelerometer coordinate system to the workpiece end coordinate system, and generate second transformed displacement information; The control unit is configured to combine the converted displacement information, the position vector and the second converted displacement information to generate the relative displacement amount.

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