Method of operating a measurement system

Abstract

A method of operating a measurement system comprising a coordinate measuring machine (200), a configurable tool holder (100) that can accept a plurality of stations (105, 106), each capable of holding a tool (95). In the method, the system measures the workpiece according to a measurement plan that includes a tool change operation and measurement of the workpiece with different tools available in the tool holder. The tool replacement operation is automatically altered based on a set of operating parameters acquired by electronic devices and sensors mounted on tools or any combination thereof on or on tool stations or in tool holders.

Description

Technical Field

[0001] This invention relates to a method for configuring and operating a coordinate measuring machine, as well as the arrangement of the coordinate measuring machine and measuring tools. Background Technology

[0002] Coordinate measuring machines (CMMs) are known and used in a variety of applications and forms in the prior art. Typically, they have a movable positioning platform that can accept many different interchangeable tools and attachments. In metrology, tools can be coordinate probes, contact probes with different ranges and various extensions (e.g., touch-triggered probes, scanning probes, or analog probes), non-contact probes such as optical probes, vision systems for optical inspection of workpieces, surface condition and roughness probes, etc. These machines typically have tool racks that hold the selection of tools and can be programmed to automatically load and unload several tools one after another, following a specific workpiece measurement procedure. In addition to CMMs, industrial robots can be configured to use such tool racks to change tools in their operations. Similarly, metalworking machines can load measuring tools and / or cutting tools from this type of tool rack.

[0003] The positioning platform on which the tool is mounted can orient the tool arbitrarily and automatically. This is common in the field of dimensional metrology, where the tool is typically mounted on an automatically actuated hinge, allowing the tool to be oriented according to the needs of the measurement task at hand.

[0004] The goal is to load and unload tools from the tool rack in a dimensionally precise, gentle, and repeatable manner, thereby minimizing impact and limiting contact forces to maintain accuracy.

[0005] Patent application EP 4414656 A1 discloses a tool holder for a CMM with multiple tool ports on a track, which can determine the position of each port along the track and transmit it to the machine controller.

[0006] Patent EP 3872447 B1 discloses a coordinate measuring machine that can automatically determine the position of the tool holder in the measuring space and adjust the tool changing process accordingly.

[0007] US 8535208 discloses a tool holder having several sockets for holding a set of measuring probes of a coordinate measuring machine and several devices for reducing coupling and decoupling stress.

[0008] Utility model DE 9010591 U1 discloses a modular tool holder with a guide that can support a variable number of slidable tool units for a coordinate measuring machine.

[0009] EP 0566719 discloses another modular probe storage box for coordinate measuring machines. This storage box includes any number of identical storage ports, each connected to an adjacent storage port.

[0010] The drawback of these known solutions is that when the machine is reconfigured to perform a new measurement program, the tool holder must also be reconfigured to provide the required tools. The new configuration must be measured and recorded in the controller of the automated machine, whether it is a coordinate measuring machine, a robot, a CNC machining tool, or another type of automated machine. In a coordinate measuring machine, this is typically performed by equipping the machine with contact probes and manually guiding the machine to sense the reference points on the tool holders one by one. The positioning of the tool holder within the machine's operating space must adhere to the manufacturer's strict specifications. Typically, the tool holder must be square to the machine's spindle, and the tracks carrying the tool stations must be carefully leveled. Different tool holders are typically desired in the tool holder, and their number can vary depending on the required and / or desired number of tools. This adds another level of complexity to the configuration, as the number of available holders and the exact nature of each holder must be recorded with the machine controller along with their positions.

[0011] All these necessary preparations represent costs because they result in non-productive time for the machines and must be performed by skilled personnel. Furthermore, they are prone to error because they involve several manual operations. Summary of the Invention

[0012] The purpose of this invention is to provide an automated system that overcomes the shortcomings and limitations of the prior art.

[0013] According to the present invention, these objectives are achieved by a method for operating a measurement system and a measurement system. Attached Figure Description

[0014] Exemplary embodiments of the present invention are disclosed in the specification and illustrated in the accompanying drawings, wherein:

[0015] Figure 1 A coordinate measurement system configured to perform the method of the present invention is illustrated schematically.

[0016] Figure 2 The various elements of the coordinate system and methods are shown as function blocks. Detailed Implementation

[0017] Figure 1 A coordinate measuring machine 200 is shown in a simplified manner with a modular tool holder 100 mounted on a reference surface 204. The tool holder 100 is configurable and can accommodate multiple tool stations 105, each capable of holding a tool 90 for the coordinate machine.

[0018] The accompanying drawings show only two tool stations to simplify the illustration and improve its comprehensibility: a tool station 105 with one tool 90 and an empty station 106. In a more realistic configuration, the tool rack 100 may include more tool stations to hold multiple tools, and may also include spare empty stations for future use. The tool stations also do not need to have a common size and shape. The tool rack may include tool stations with different shapes, shaped to hold each particular model or type of tool.

[0019] Advantageously, the modular tool rack 100 can accept a variable number of tool stations of different natures at different locations. In this way, it provides the operator with great flexibility to fully configure (and reconfigure) the tool storage according to planned measurements. The tool rack can be configured to allow tool stations to be moved on the tool rack, i.e., to allow manual or automatic repositioning along one or more axes, for example, by means of sliders, tightening devices, and / or actuators.

[0020] Figure 1 A bridge-type CMM with a spindle 207 is shown, which can move automatically and with high precision along three coordinate axes X, Y, and Z, and an orientable wrist 280 mounted thereon can hold the measuring tool and can be oriented by rotation about two or possibly three rotation axes A, B. This arrangement is common and will be described exclusively in this disclosure to illustrate an example of the invention, but it is not the only possible example. The invention is equally applicable to articulated arm coordinate machines as well as industrial robots and machine tools, provided they are equipped with modular tool holders and perform the claimed methods.

[0021] The movement of tool 95, mounted on the CMM's operational end, is determined and controlled by CMM controller unit 220, which operates on the X, Y, Z, A, and B axes of CMM 200 to measure workpieces in the accessible measurement space according to a predetermined measurement plan. Typically, the measurement plan requires different specialized tools to perform different operations; therefore, the measurement plan includes tool change operations. The coordinate measuring machine has an automatic connector that can connect and disconnect any available tool in tool holder 100. Tool change operations in the measurement plan may involve the following steps: approaching the tool holder, aligning the connector with empty station 106, leaving the tool in the empty station, moving to the station holding the selected tool 90, and loading the tool onto the CMM.

[0022] According to an important aspect of the invention, tool rack 100 is combined with tool rack controller 120, which communicates with machine controller 220 and a plurality of electronic devices that provide operating parameters for the tool rack, the tools mounted on the tool rack, the coordinate machine, and the environment. For example, in the cases of devices 152 and 154, communication between tool rack controller 120 and electronic devices (hereinafter referred to as “sensors”, having the same meaning) can be ensured by (electrical and / or optical) cable 131, or it can rely on any suitable form of wireless communication, such as that shown for sensors 164 and 162.

[0023] Sensors that communicate with the tool rack controller can be placed on the tool rack itself (such as sensor 152), on the tool station (e.g., in the case of sensor 154), on the tool itself as shown for device 162, or in any other location (e.g., in the case of camera 158 and sensor 164).

[0024] The nature of the sensors is unrestricted. Environmental sensors can provide information about temperature, humidity, noise, ambient light, proximity of the operator or other body, etc. On a tool rack, some sensors can be: occupancy sensors, which provide information about the presence of a tool at a defined workstation; vibration sensors; shock sensors; weight sensors, which are configured to weigh the tool station and determine the mass of the tool mounted thereon; dimensional measuring devices, which are configured to determine the dimensions of the tool at the tool station; and many other sensors.

[0025] The tool rack of the present invention can be designed with any suitable mechanism to connect and position tool stations 105, 106. Where the positions of the stations are not indexed, the tool rack or station may include special measuring devices that provide the relative position of the determined station with respect to the tool rack.

[0026] Sensors mounted on tooling stations can take various forms. In critical cases, tooling stations may have devices configured to determine the size or mass of a tool, the presence of a tool, its model, or a unique identifier for a tool present at the station; however, any sensor may be mounted on a tooling station when needed.

[0027] In some cases, such as when a sensor is embedded in the tool itself, wireless communication is required. This is the case with sensor 162, which may be a memory that provides, for example, a unique part code that identifies tool 90 or its model, or its internal temperature, or the state of its internal battery, or any other important operating parameters.

[0028] The sensor can be located in any useful location. For example, sensor 164 can be a light barrier arranged to provide a signal when the CMM head approaches the tool holder, or a vibration sensor, or a force sensor that measures the force generated during tool change operations, or any other sensor.

[0029] Electronic devices can also be actuators, particularly in the form of electric motors, for actuating tool holders, tool stations, and / or probes when located in tool stations. In some cases, these actuators can be electric motors located in the tool station for locking / unlocking probes from the probe head, for example, by actuating a locking mechanism of such probes. In other cases, these actuators can be electric motors configured to move and / or orient one or more tool stations relative to a configurable tool holder.

[0030] Figure 2 The components of the measurement system are shown in a more schematic form. Machine controller 220 and tool rack controller 120 are interconnected via data link 150, which can transmit digital information. The two controllers 220 and 120 can be part of a digital data network (e.g., an IP network), in which case link 150 can be a wired or wireless physical channel capable of supporting IP packets. However, typically, controllers 120 and 120 can be connected in any manner.

[0031] The machine controller can be implemented by a personal computer or industrial PC running a dedicated control program. In its task, it is configured to obtain the determined workpiece measurement plan by acquiring it from its local storage device 224 or from the Internet 440, or by creating a plan from the workpiece's nominal model and instructions from the operator, or by any other means.

[0032] The measurement plan includes measurement operations, in which probe 95 operates on the workpiece, and controller 220 outputs the coordinates of points on the workpiece surface and tool change operations, as described above.

[0033] Machine controller 220 can access interactive input / output device 235, which is used to reproduce measurement results and / or obtain input and commands from human operators. The interactive device can be a local device, such as a monitor / keyboard / mouse directly connected to controller 220, or a remote device associated with a different computer communicating with controller 220 via a network. The interactive device may also include control lights, control widgets, or other similar devices.

[0034] The tool rack controller 120 communicates with a group of 180 electronic devices via wired or wireless means or possibly via an interface device not shown. This group of electronic devices is configured to provide operating parameters for the tool rack, the tools mounted therein, coordinate machines, or the environment or other parameters.

[0035] In terms of the overall operating parameters of the tool rack, this group of 180 electronic devices may include:

[0036] - Collision detector,

[0037] - Position and / or angle sensors, which respectively provide the position and orientation of the tool holder relative to a suitable coordinate system (e.g., the coordinate system of a CMM).

[0038] - Devices that provide indicators of the health status or wear of the tool rack, such as a counter representing the number of loading / unloading operations associated with the entire tool rack, or

[0039] - A device that provides state variables, which can assume values ​​such as "operation", "fault", "requires maintenance", etc.

[0040] Sensors attached to a single tool station may include:

[0041] - Devices that provide health or wear indicators for workstations, such as counters showing the number of loading / unloading operations at a single tool station.

[0042] - A device that provides state variables, which can assume values ​​such as "operation", "fault", "requires maintenance", etc.

[0043] - Position and / or angle sensors, which respectively provide the position and orientation of the workstation relative to the tool holder.

[0044] - Equipment that provides assessment of the tool's position within the workstation, such as "empty," "correctly loaded," or "incorrectly loaded." This functionality can be ensured, in particular, by proximity sensors based on inductive, capacitive, or optical sensing, light barriers, microswitches, reed relays, Hall effect sensors, etc.

[0045] Sensors can also provide operating parameters for each tool. Depending on these parameters, these sensors can be attached to the tool station, placed at a distance (e.g., a camera capturing images of the tool processed by automatic recognition algorithms), or embedded within the tool itself. Key operating parameters for the tool include:

[0046] - The type or model of the tools installed at the workstation. This can be achieved through code reading, RFID tags, image recognition, coded contacts, etc.

[0047] - A unique part number, possibly based on the same technology as the aforementioned model identification equipment, for tools mounted at the workstation.

[0048] - Health or wear status, such as trigger counters, scan distance, wear information obtained by actively moving tools in an inspection device attached to or near the tool rack, such as optical control for ruby ​​touch balls.

[0049] -Calibration status

[0050] - The weight and / or size of the tool, for example, captured by a strain gauge in the workstation or a light barrier in the tool holder.

[0051] - Battery charging status, where applicable.

[0052] Several environmental parameters can be obtained. These environmental parameters include:

[0053] -temperature

[0054] -humidity

[0055] -vibration,

[0056] wait.

[0057] The list above is not exhaustive.

[0058] The measurement system is used to take into account operating parameters. For example, the measurement plan can be modified based on operating parameters before its execution. Advantageously, the machine controller or tool rack controller can match the tools required by the plan with the tools available in the tool rack and modify the tool change operations in the plan so that the required tools are loaded at a specified time, regardless of their position in the tool rack and / or the position of the tool rack in the CMM.

[0059] The system is preferably configured to detect a mismatch between the required tools and the available tools, and in this case, to avoid executing the program and display a warning on the interactive device 235, preferably suggesting a corrective action.

[0060] According to the variant, the machine controller or tool rack controller can be configured to select available tools in such a way as to distribute wear among several equivalent available tools, or to avoid using tools that are too worn or have weak batteries until they are properly maintained and recharged individually.

[0061] Preferably, particularly when the modular tool rack 100 comprises multiple tool stations of the same shape, the measuring system is also configured to optimize the position of tools within the tool rack to minimize program execution time, for example, by moving the most frequently used tools to tool stations closer to the workpiece, while unused, uncalibrated, and worn tools are moved to tool stations further away. When possible, the program is modified so that this reorganization of tools is performed automatically at the outset. However, where appropriate, the measuring system can automatically select the desired configuration of the optimized tool rack plan and present it on display 235 for the operator to construct. In this second semi-automatic variant, the system can also automatically select some configurations that require manual intervention, for example, because they require changes to tool stations or rearrangements. Alternatively or complementaryly, the measuring system can instruct the configurable tool rack to automatically achieve (at least a portion thereof) the desired configuration via one or more electronic devices of the tool rack and / or tool stations. The system can then use operating parameters to verify that the desired configuration has been achieved.

[0062] In addition to execution time, other objectives can be considered for optimizing measurement plans, such as using fewer tools to reduce calibration operations, using more accurate tools (less worn, recently calibrated or manufactured, at the right temperature) for critical measurements, and preparing tools by pre-powering or preheating them in consideration of tool replacement.

[0063] The measurement system can also suggest and schedule periodic automatic recalibrations during the hidden time of the measurement system and programming plan (e.g., soundness checks using special features on the tool rack). Alternatively or complementaryly, the measurement system can also be configured to change tool change operations so that periodic automatic recalibrations can be performed during the (pre-planned) hidden time of the system and / or programming plan.

[0064] Reducing tool rack deflection can be considered to optimize tool rack configuration, thereby improving the reliability of loading and unloading operations. The tool rack can include a deflection detector to help reduce this source of error. Alternatively or additionally, if deflection is detected, it can be compensated for by changing the trajectory of the tool change operation.

[0065] The optimization can also include collision avoidance objectives. Sensors can also include proximity detectors of various types, such as light barriers, cameras, and LiDAR, and the system can be configured to issue an alarm when the proximity detector indicates that a collision is imminent or may occur.

[0066] The measurement system can also use the acquired operating parameters to support other functions and / or services, such as the calibration of the tool rack and / or tool station (e.g., using the provided tool rack relative to a suitable coordinate system and / or the tool station with respect to the position and / or orientation of the tool rack).

[0067] Environmental parameters (such as temperature and humidity) can be used to calibrate measurement data, trigger predictive maintenance, and / or plan scheduled maintenance.

[0068] Figure Labels

[0069] 90 Tools or probes stored in the tool rack

[0070] 95. Tools or probes equipped on the commercial side of CMM.

[0071] 100 Tool Rack

[0072] 105 workstations

[0073] 106 empty workstations

[0074] 120 Tool Rack Controller

[0075] Communication link between the 131 tool rack controller and the sensor

[0076] Communication link between the 150 machine controller and the tool rack controller

[0077] 152 Sensors or electronic devices, such as occupancy sensors

[0078] 154 Sensors or electronic devices, such as vibration sensors

[0079] 158 camera

[0080] 162 Wireless sensors or electronic devices, such as model number

[0081] 164 wireless sensors or electronic devices, such as light barriers

[0082] 180 electronic devices and sensors

[0083] 200CMM

[0084] 204 reference surface

[0085] 207Z axis

[0086] 220CMM controller

[0087] 224 storage areas

[0088] Communication link from 230 to the interactive console

[0089] 235 Interactive Console

[0090] Communication link between the 250 machine controller and the CMM

[0091] 270cm x Y z axis motor and position sensor

[0092] 280 motor and position sensor that can reorient the wrist's axis ABC

[0093] 440 Internet, remote servers and resources

Claims

1. A method of operating a measurement system, the measurement system comprising a coordinate measuring machine and a configurable tool rack capable of accepting multiple workstations, each workstation capable of holding a tool, the method comprising: A plan is obtained for measuring a workpiece using the coordinate measuring machine, the plan including tool changing operations and measuring the workpiece using different tools available in the tool holder. Its features A set of operating parameters is obtained from one or more electronic devices installed on the tool rack and / or in the workstation and / or in the loaded tool. The tool replacement operation is changed based on the aforementioned operating parameters. Execute the plan.

2. The method according to claim 1, wherein the operating parameters include the position and / or orientation of the tool holder relative to the coordinate measuring machine.

3. The method according to claim 1, wherein, The acquisition of the operating parameters is performed by the electronic tool rack controller, and the operating parameters are subsequently transmitted to the machine controller of the coordinate measuring machine, which executes the changes to the plan and the execution.

4. The method according to claim 1, wherein the operating parameters include the health or wear condition of the tool rack or workstation or the loaded tool.

5. The method of claim 4, wherein the tool changing operation is modified according to the health condition or wear condition of the workstation or tool in order to avoid using unhealthy workstations or tools or spreading wear between workstations or tools.

6. The method according to claim 1, wherein the operating parameters include a type identifier for the workstation or tool, or a unique identifier for the workstation or tool, or the position of the workstation relative to the tool rack.

7. The method according to claim 1, wherein the operating parameters include the weight and / or dimensions of the loaded tool.

8. The method according to any one of the preceding claims, wherein the electronic device comprises one or more of the following: a camera, a strain gauge, a light barrier, an RFID reader, a position encoder, an angle encoder, an accelerometer, a vibration sensor, an electric actuator, or a motor.

9. The method of claim 1, wherein the plan is changed in response to changes in the operating parameters during the execution.

10. The method according to claim 1, wherein the method comprises: The desired configuration of the tool rack is automatically selected based on the plan. The desired configuration is made available to the operator by outputting peripheral devices and / or the configurable tool rack is instructed to actuate the desired configuration. Use the operating parameters to verify that the operator and / or the configurable tool rack has achieved the desired configuration.

11. The method according to claim 10, wherein, The selection of the desired configuration includes optimization steps aimed at reducing bending of the tool rack and / or the execution time of the program and / or wear of hardware components.

12. The method according to claim 10 or claim 11, wherein, The configurable tool holder is configured to accept a variable number of workstations and / or multiple workstations of different models; the desired configuration includes: the desired number of workstations, the desired model of at least one of the workstations, and / or the desired relative position and / or orientation of at least one of the workstations with respect to the tool holder and / or coordinate measuring machine and / or the workpiece.

13. The method according to claim 1, wherein the method includes triggering maintenance operations based on the operating parameters.

14. The method of claim 1, wherein the method includes correcting the results of the measurement based on information about vibration, temperature, or humidity included in the operating parameters.

15. The method of claim 1, wherein the method includes interrupting the plan and triggering a predetermined collision response upon receiving a collision signal included in the operating parameters.

16. The method of claim 1, wherein the method includes modifying the plan based on the operating parameters before the plan is executed, and / or issuing an alarm or corrective action upon detecting a mismatch between the operating parameters and the required operating parameters for executing the plan.

17. A measurement system comprising a coordinate measuring machine having an electronic machine controller and a configurable tool rack capable of accepting multiple workstations, each workstation capable of loading tools for the coordinate measuring machine, the measurement system including an electronic tool rack controller in communication with the machine controller, the electronic tool rack controller being configured to read operating parameters from a plurality of electronic devices mounted on the tool rack and / or in the workstations and / or in the loaded tools, the machine controller and the tool rack controller being programmed to perform the method according to claim 1.

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