Method for compensating dynamic delay error of trigger probe in coordinate measuring machine
Patent Information
- Application Number
- CN202611137205.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-07-29
- Publication Date
- 2026-09-25
AI Technical Summary
前者要维持高精度需针对不同测杆、不同触发方向进行大量标定，后者因难以精确辨识触发力、测杆挠曲与信号传输等耦合时变环节，模型阶次高、解算复杂
[0011]与普通正反向测量取平均不同，本发明并非通过增加独立测量次数来降低随机误差，而是在一次触发探测循环中，将通常仅用于释放或复位判断的回撤阶段测头信号转化为动态延迟补偿信息，并由同一数据采集单元锁存接近阶段和回撤阶段的触发位置坐标，从而实现在线补偿。该方法不需要额外传感器，不需要预先建立复杂动力学模型，也不需要单独标定测头机械响应延迟或信号传输延迟。与已有技术相比，本发明有益效果体现在：
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Figure CN122813745A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of precision coordinate measurement technology, specifically relating to a method for compensating dynamic delay error of a trigger-type probe in a coordinate measuring machine, applicable to online compensation of dynamic delay error in rapid measurement processes of a micro-nano precision coordinate measuring machine. Background Technology
[0002] Trigger-type probes are widely used in coordinate measuring machines (CMMs) due to their simple structure and good repeatability. Their measurement accuracy directly affects the reliability of the inspection results. In conventional trigger-type measurements, after the probe contacts the workpiece, when the probe signal reaches the trigger criterion, the data acquisition unit immediately latches the current position coordinates for calculation.
[0003] However, unavoidable time delays exist in each stage, from probe contact, mechanism response, signal generation and transmission to coordinate latching. When there is relative movement between the probe and the workpiece, this delay is converted into spatial position deviation, forming a dynamic delay error, which becomes more significant the faster the measurement speed. Therefore, to ensure the measurement accuracy of micro-nano precision coordinate measuring machines, the trigger speed is usually limited to a low range, severely restricting measurement efficiency.
[0004] Existing compensation methods mainly fall into two categories: one is to establish a velocity-error mapping model (such as polynomial fitting) by calibrating the triggering error at different speeds; the other is to establish a probe triggering dynamics model for real-time calculation. The former requires extensive calibration for different probes and triggering directions to maintain high accuracy, while the latter suffers from difficulties in accurately identifying time-varying coupled elements such as triggering force, probe deflection, and signal transmission, resulting in high-order models and complex solutions. Both methods generally rely heavily on prior calibration and accurate modeling, making it difficult to directly embed them into conventional triggering processes for online compensation.
[0005] In summary, the key problem that urgently needs to be solved in this field is how to provide a dynamic delay error compensation method that is computationally simple, has good real-time performance, and is applicable to conventional triggering processes without increasing hardware, relying on complex models, or cumbersome calibration. Summary of the Invention
[0006] This invention addresses the shortcomings of existing technologies by providing a method for compensating for dynamic delay errors in trigger-type probes within a coordinate measuring machine (CMM). Unlike conventional methods that only utilize the trigger-locked coordinates during the approach phase, this method triggers and locks the probe's position coordinates during the pullback phase of a single trigger-probe cycle. Based on the inherent relationship of opposite directions in the dynamic delay errors of the two locked coordinates, both are used together as compensation data. This allows for the offsetting of delay errors through coordinate calculations within a complete trigger-probe cycle, achieving real-time compensation.
[0007] The present invention adopts the following technical solution to solve the technical problem: The dynamic delay error compensation method for the trigger-type probe in the coordinate measuring machine of this invention is characterized by the following: the measuring machine includes a trigger-type probe, a data acquisition unit, a control system, and motion axes in the X, Y, and Z directions; the trigger-type probe is installed at the end of the Z-axis of the coordinate measuring machine; the control system is used to control at least one of the trigger-type probe and the workpiece being measured to move along a predetermined measurement path; the data acquisition unit is used to acquire the probe trigger signal and latch the corresponding spatial coordinates; the trigger-type probe outputs a trigger signal when the probe contacts the workpiece being measured and the probe signal meets the preset trigger criterion; the dynamic delay error compensation method for the trigger-type probe is completed in one trigger detection cycle according to the following process: First, the state to be measured is that the trigger probe and the workpiece are not in contact with each other. In the state to be measured, the two are controlled to approach each other along the measurement path, and the process of the two approaching each other is defined as the approach stage. When they approach each other and the probe signal reaches the trigger set value on the rising edge, it is determined that the two have reached the trigger state. At this time, the data acquisition unit latches the segment trigger position coordinate P2 of the approach stage and controls the two to stop the approach movement. Subsequently, the control trigger probe and the workpiece being measured move away from each other along the measurement path, and the process of the two moving away from each other is defined as the retraction stage; as they continuously retract to restore the two to the state to be measured, and when the probe signal falls to the trigger set value on the falling edge, the data acquisition unit latches the trigger position coordinate P2' of the retraction stage in real time. During the approach and retraction phases, the same trigger setting value, the same movement speed, and the same measurement path are used. The compensated trigger position coordinate P0 is calculated based on the trigger position coordinate P2 and trigger position coordinate P2', and the compensated trigger position coordinate P0 is used for subsequent measurement calculations, thereby realizing dynamic delay error compensation of the trigger probe.
[0008] The method for compensating for dynamic delay error of the trigger probe in the coordinate measuring machine of this invention is characterized by: setting the workpiece to be measured as a fixed component or a moving component; setting the trigger probe to be a moving component or a fixed component; and performing dynamic delay error compensation of the trigger probe in the measurement mode in which the moving component moves along the X direction, according to the following steps: Step 1: Set the fixed component and the moving component to the state to be measured, and put the moving component in the initial position; Step 2: Control the moving component to enter the approach stage, so that the moving component moves continuously along the positive X-axis at a constant speed v. When the probe signal reaches the trigger set value on the rising edge, the data acquisition unit latches the approach stage trigger position coordinates P2(x2,y2,z2), and the control system controls the moving component to stop moving. Step 3: Control the moving component to enter the retraction phase, causing the moving component to retract to its initial position along the negative X-axis at a constant speed v; during the retraction phase, when the probe signal falls to the trigger set value on the falling edge, the data acquisition unit latches the retraction phase trigger position coordinate P2'. (x2', y2', z2'); Step 4, Data Processing: Under the condition that the same absolute value of the movement speed v is used in both the approach and retreat phases, and the same triggering criterion is used in both phases, the triggering position coordinates P2(x2, y2, z2) in the approach phase and P2'(x2', y2', z2') in the retreat phase are considered to be symmetrical about the compensated triggering position coordinates P0(x0, y0, z0) in the triggering direction. Then, the compensated triggering position coordinates are calculated according to formula (1): (1); In formula (1): by Characterization , or axial direction, i.e.: ; P 0i The coordinate components of the compensated trigger position coordinate P0 in the i direction; P 2i The coordinate components of the approach phase trigger position coordinate P2 in the i direction; P 2i The coordinate components of 'the trigger position coordinate P2 for the pullback phase' in the i direction; d i For the trigger direction coefficient, when direction i is the trigger direction, d i = 1, indicating that the coordinate in that direction participates in compensation; when direction i is not the triggering direction, d i = 0, indicating that the coordinate in that direction is not included in the compensation; in the measurement mode where the moving component moves along the X direction, d x =1,d y = 0, d z = 0; Step 5: Use the compensated trigger position coordinates calculated by equation (1) as the actual measurement point coordinates and use them for the calculation of subsequent measurement results to realize dynamic delay error compensation of the trigger probe.
[0009] The characteristic of the dynamic delay error compensation method for the trigger-type probe in the coordinate measuring machine of this invention is that the triggering direction is one or more of the X, Y, and Z directions; the triggering direction coefficient d in equation (1) is also present. i Used to define the coordinate direction involved in compensation; when direction i is the trigger direction, d... i=1, when the i direction is a non-triggering direction, d i =0.
[0010] The characteristic of the dynamic delay error compensation method for the trigger probe in the coordinate measuring machine of the present invention is that the trigger position coordinates P2 in the approach stage and the trigger position coordinates P2' in the retreat stage are both latched and obtained by the same data acquisition unit in the same trigger detection cycle.
[0011] Unlike conventional forward and reverse measurements that average each other, this invention does not reduce random errors by increasing the number of independent measurements. Instead, within a single trigger detection cycle, it transforms the probe signal during the retraction phase—typically used only for release or reset judgments—into dynamic delay compensation information. This information is then latched by the same data acquisition unit, storing the trigger position coordinates for both the approach and retraction phases, thus achieving online compensation. This method requires no additional sensors, no pre-established complex dynamic models, and no separate calibration of the probe's mechanical response delay or signal transmission delay. Compared to existing technologies, the advantages of this invention are: 1. This invention introduces a retraction phase into a single trigger detection cycle to obtain the trigger position coordinates corresponding to the approach and retraction phases, and performs mean compensation on the coordinate components in the trigger direction. Since the movement directions of the approach and retraction phases are opposite, under the same trigger setting value and movement speed conditions, the dynamic delay errors of the two phases show opposite trends in the trigger direction. Therefore, the above mean compensation can effectively offset the dynamic delay error, thereby significantly improving the measurement speed while ensuring measurement accuracy. 2. This invention utilizes paired trigger coordinate data to complete dynamic delay error compensation. The compensation calculation mainly involves the mean value calculation of coordinate components. The calculation process is simple and easy to embed into existing measurement controllers or data processing flows for online compensation. This method does not require additional hardware sensors, nor does it require the establishment of complex speed-delay time mapping relationships or probe dynamic models. This helps reduce calibration workload and system maintenance costs, and improves the applicability of the method in practical coordinate measuring machine scenarios. Attached Figure Description
[0012] Figure 1 This is a schematic diagram of a coordinate measuring machine (CMM) measurement system.
[0013] Figure 2 This is a schematic diagram of the measurement process triggered by a proximity-stage trigger probe along the positive X-axis.
[0014] Figure 3 This is a schematic diagram of the measurement process where the trigger probe is triggered along the negative X-axis during the retraction phase.
[0015] Figure 4 This diagram illustrates the relationship between the X-axis coordinates and probe signals during the approach and retraction of a trigger-type probe.
[0016] The numbers in the diagram are: 1. Main body of the coordinate measuring machine; 2. Z-axis of motion; 3. Trigger probe; 4. Measuring rod; 5. Workpiece to be measured; 6. Measuring ball. Detailed Implementation
[0017] See Figure 1 In this embodiment, the coordinate measuring system includes a coordinate measuring machine body 1, X, Y and Z motion axes, a trigger probe 3, a probe rod 4 and a probe 6. The trigger probe 3 is installed at the end of the Z motion axis 2 of the coordinate measuring machine. The workpiece 5 to be measured is placed on the work platform. The system configuration also includes a data acquisition and control unit. The X, Y and Z motion axes are driven by the control unit to realize the relative movement between the trigger probe and the workpiece to be measured.
[0018] In this embodiment, the dynamic delay error compensation method for the trigger probe in the coordinate measuring machine is as follows: The control system controls at least one of the trigger probe 3 and the workpiece 5 to move along a predetermined measurement path; the data acquisition unit acquires the probe trigger signal and latches the corresponding spatial coordinates; the trigger probe outputs a trigger signal when the probe contacts the workpiece and the probe signal meets the preset trigger criterion; the dynamic delay error compensation method for the trigger probe is completed in one trigger detection cycle according to the following process: First, the test state is defined as the test state in which the trigger probe and the workpiece are not in contact. In the test state, the two are controlled to approach each other along the measurement path, and the process of the two approaching each other is defined as the approach stage. When they approach each other and the probe signal reaches the trigger set value on the rising edge, it is determined that the two have reached the trigger state. At this time, the data acquisition unit latches the segment trigger position coordinate P2 of the approach stage and controls the two to stop the approach movement.
[0019] Subsequently, the control trigger probe and the workpiece being measured move away from each other along the measurement path, and the process of them moving away from each other is defined as the retraction stage. As they retract continuously to restore them to the state to be measured, and when the probe signal falls to the trigger set value on the falling edge, the data acquisition unit latches the trigger position coordinate P2' of the retraction stage in real time.
[0020] During the approach and retraction phases, the same trigger setting value, the same movement speed, and the same measurement path are used. The compensated trigger position coordinate P0 is calculated based on the trigger position coordinate P2 and trigger position coordinate P2', and the compensated trigger position coordinate P0 is used for subsequent measurement calculations, thereby realizing dynamic delay error compensation of the trigger probe.
[0021] Set the workpiece 5 to be measured as either a fixed component A or a moving component B; set the trigger probe 3 to either a moving component B or a fixed component A; in the measurement mode where the moving component B moves along the X direction, perform dynamic delay error compensation for the trigger probe according to the following steps: Step 1: Set the fixed component A and the moving component B to the state to be measured, and make the moving component B be in the initial position W0; Step 2: Control the moving component B to enter the approach stage, so that the moving component B moves continuously along the positive X-axis at a constant speed v. When the probe signal reaches the trigger set value on the rising edge, the data acquisition unit latches the approach stage trigger position coordinates P2(x2,y2,z2), and the control system controls the moving component B to stop moving. Step 3: Control the moving component B to enter the retraction phase, causing it to retract at a constant speed v along the negative X-axis to its initial position W0. During the retraction phase, when the probe signal falls to the trigger set value on the falling edge, the data acquisition unit latches the retraction phase trigger position coordinate P2'. (x2', y2', z2'); Step 4, Data Processing: Perform dynamic delay error compensation calculation through data processing.
[0022] To explain the formation mechanism of dynamic delay error, the trigger position coordinate P2 of the proximity stage latch is analyzed. The theoretical trigger position coordinate corresponding to the trigger setpoint is P0, and the real-time position coordinate when the trigger probe 3 completes the mechanical response and generates the trigger signal is P1. There is a mechanical response delay time t1 between P0 and P1, and a signal transmission, data processing, and coordinate latching delay time t2 between P1 and the final latched P2 by the data acquisition unit. Since the trigger probe 3 continues to move along the positive X-axis during the time interval t1 + t2, the proximity stage trigger position coordinate P2 has a positional deviation relative to the theoretical position P0 along the positive X-axis: Δx = x2 - x0; During the retraction phase, when the probe signal falls to the trigger setpoint on the falling edge, the position coordinate of the trigger probe 3 when it completes the mechanical response and generates the trigger signal is P1', and the trigger position coordinate of the retraction phase latched by the data acquisition unit is P2'. The retraction phase also involves a mechanical response delay t1' and a coordinate latching delay t2'. Therefore, the trigger position coordinate P2' of the retraction phase has a position deviation Δx' = x2' - x0 relative to the theoretical position P0 along the negative X-axis. When the approach and retraction phases use the same trigger setpoint, the same movement speed, opposite movement directions, and the same measurement path, the position deviations introduced by the dynamic delay in the approach and retraction phases are opposite in direction in the trigger direction, satisfying Δx'=−Δx. Therefore, we can obtain: .
[0023] The parameters P1, P1', t1, t2, t1', and t2' mentioned above are only used to illustrate the formation process of dynamic delay error and are not parameters that must be directly measured or solved separately in this method. Because the processes of probe mechanical response, signal transmission, data processing, and coordinate latching are interdependent and affected by factors such as trigger speed, probe structure, control system response, and sampling timing, direct measurement or accurate solution of intermediate positions and delay times is quite difficult. The data actually used for compensation calculation in this method are the approach phase trigger position coordinates P2 and the retreat phase trigger position coordinates P2' latched by the data acquisition unit in one trigger detection cycle, thus avoiding the dependence on solving intermediate variables such as P1, P1', t1, t2, t1', and t2' separately.
[0024] Based on the above principle, under the condition that the same absolute value of the movement speed v is used in both the approach and retreat phases, and the same triggering criterion is used in both phases, the triggering position coordinates P2(x2, y2, z2) of the approach phase and the triggering position coordinates P2' of the retreat phase are... (x2', y2', z2') are considered to be symmetrical about the compensated trigger position coordinates P0(x0, y0, z0) in the trigger direction. The compensated trigger position coordinates are then calculated using equation (1): (1) In formula (1): Characterization , or axial direction, i.e.: ; P 0i The coordinate components of the compensated trigger position coordinate P0 in the i-direction; P 2i The coordinate components of the approach phase trigger position coordinate P2 in the i-direction; P 2i The coordinate components of 'the trigger position coordinate P2' in the i-direction; d i For the trigger direction coefficient, when direction i is the trigger direction, d i = 1, indicating that the coordinate in that direction participates in compensation; when direction i is not the triggering direction, d i = 0, indicating that the coordinate in that direction is not included in the compensation; in the measurement mode where the moving component B moves along the X direction, d x =1, dy=0, dz = 0.
[0025] Step 5: Use the compensated trigger position coordinates calculated by equation (1) as the actual measurement point coordinates and use them for the calculation of subsequent measurement results to realize dynamic delay error compensation of the trigger probe.
[0026] In specific implementation, the triggering direction is one or more of the X direction, Y direction, and Z direction; the triggering direction coefficient di in equation (1) is used to limit the coordinate direction involved in the compensation. When the i direction is the triggering direction, di = 1, and when the i direction is a non-triggering direction, di = 0.
[0027] The trigger position coordinates P2 during the approach phase and P2' during the retreat phase are both latched by the same data acquisition unit in the same trigger detection cycle.
[0028] Figure 2 and Figure 3 The diagram shows a method where the workpiece 5 is a fixed component, and the trigger probe 3 is a moving component. The trigger probe 3 is moved along the X-direction to compensate for the dynamic delay error of the trigger probe. Figure 2 This diagram illustrates the measurement process triggered by the proximity-stage trigger probe along the positive X-axis. Figure 3 The measurement process of the trigger probe during the retraction phase along the X-axis is illustrated. Due to the mechanical response delay of the probe and the signal transmission and processing delay, there are theoretical trigger position coordinates and actual latching position coordinates in both the approach and retraction phases.
[0029] Figure 4 The diagram illustrates the correspondence between the probe output signal and the X-axis latched coordinates during the approach and retraction processes of the trigger-type probe 3. During approach, the X-axis moves towards the object being measured, and the probe output signal gradually increases accordingly. When the theoretical probe output signal reaches the probe signal trigger setting value, the corresponding X-axis coordinate is the theoretical latched coordinate x0. Due to the mechanical response delay time t1 of the probe, when the actual probe output signal reaches the trigger setting value, the X-axis has already moved to coordinate x1. Subsequently, due to the signal transmission and processing delay time t2, when the control system actually completes coordinate latching, the X-axis has already moved to coordinate x2. Therefore, x2 is the actual latched coordinate during the approach phase.
[0030] During the retraction process, the X-axis moves in the opposite direction, and the probe output signal gradually decreases. When the theoretical probe output signal reaches the probe signal trigger set value, the corresponding X-axis coordinate is the theoretical latching coordinate x0 of the retraction phase. Due to the mechanical response delay time t1' of the probe, when the actual probe output signal reaches the trigger set value, the X-axis moves to coordinate x1'; due to the signal transmission and signal processing delay time t2', when the control system actually completes coordinate latching, the X-axis moves to coordinate x2'. Therefore, x2' is the actual latching coordinate of the retraction phase. Under the conditions of using the same trigger set value and the same movement speed, x2' and x2 are symmetrical about the theoretical latching coordinate x0. The vertical dashed line in the figure represents the correspondence between the probe signal change time and the corresponding X-axis coordinate.
[0031] This invention is applicable to applications where coordinate measuring machines (CMMs) use trigger-type probes for rapid point detection, dimensional measurement, and contour measurement. This method fully utilizes the approach and retraction trigger information within a single probe cycle, achieving dynamic delay error compensation without requiring additional hardware or complex dynamic models. This improves the accuracy, stability, and engineering applicability of rapid trigger measurements.
Claims
1. A method for compensating for dynamic delay error of a trigger-type probe in a coordinate measuring machine, characterized by: The measuring machine includes a trigger probe, a data acquisition unit, a control system, and motion axes in the X, Y, and Z directions; The trigger probe is mounted at the Z-axis end of the coordinate measuring machine; the control system controls at least one of the trigger probe and the workpiece to move along a predetermined measurement path; the data acquisition unit acquires the probe trigger signal and latches the corresponding spatial coordinates; the trigger probe outputs a trigger signal when the probe contacts the workpiece and the probe signal meets the preset trigger criterion; the dynamic delay error compensation method for the trigger probe is completed in one trigger detection cycle according to the following process: First, the state to be measured is that the trigger probe and the workpiece are not in contact with each other. In the state to be measured, the two are controlled to approach each other along the measurement path, and the process of the two approaching each other is defined as the approach stage. When they approach each other and the probe signal reaches the trigger set value on the rising edge, it is determined that the two have reached the trigger state. At this time, the data acquisition unit latches the segment trigger position coordinate P2 of the approach stage and controls the two to stop the approach movement. Subsequently, the control trigger probe and the workpiece being measured move away from each other along the measurement path, and the process of the two moving away from each other is defined as the retraction stage; as they continuously retract to restore the two to the state to be measured, and when the probe signal falls to the trigger set value on the falling edge, the data acquisition unit latches the trigger position coordinate P2' of the retraction stage in real time. During the approach and retraction phases, the same trigger setting value, the same movement speed, and the same measurement path are used. The compensated trigger position coordinate P0 is calculated based on the trigger position coordinate P2 and trigger position coordinate P2', and the compensated trigger position coordinate P0 is used for subsequent measurement calculations, thereby realizing dynamic delay error compensation of the trigger probe.
2. The method for compensating for dynamic delay error of a trigger-type probe in a coordinate measuring machine according to claim 1, characterized in that: Set the workpiece (5) to be measured as a fixed component (A) or a moving component (B); set the trigger probe (3) to either a moving component (B) or a fixed component (A); in the measurement mode where the moving component (B) moves along the X direction, perform dynamic delay error compensation for the trigger probe according to the following steps: Step 1: Set the fixed component (A) and the moving component (B) to the state to be measured, and put the moving component (B) in the initial position (W0). Step 2: Control the moving component (B) to enter the approach stage, so that the moving component (B) moves continuously along the positive X-axis at a constant speed v. When the probe signal reaches the trigger set value on the rising edge, the data acquisition unit latches the approach stage trigger position coordinates P2(x2,y2,z2), and the control system controls the moving component (B) to stop moving. Step 3: Control the moving component (B) to enter the retraction phase, so that the moving component (B) retracts to the initial position (W0) along the negative X-axis at a constant speed v; during the retraction phase, when the probe signal falls to the trigger set value on the falling edge, the data acquisition unit latches the trigger position coordinates P2'(x2', y2', z2') of the retraction phase. Step 4, Data Processing: Under the condition that the same absolute value of the movement speed v is used in both the approach and retreat phases, and the same triggering criterion is used in both phases, the triggering position coordinates P2(x2, y2, z2) in the approach phase and P2'(x2', y2', z2') in the retreat phase are considered to be symmetrical about the compensated triggering position coordinates P0(x0, y0, z0) in the triggering direction. Then, the compensated triggering position coordinates are calculated according to formula (1): （1）； In formula (1): by Characterization , or axial direction, i.e.: ; P 0i The coordinate components of the compensated trigger position coordinate P0 in the i direction; P 2i The coordinate components of the approach phase trigger position coordinate P2 in the i direction; P 2i The coordinate components of 'the trigger position coordinate P2 for the pullback phase' in the i direction; d i For the trigger direction coefficient, when direction i is the trigger direction, d i = 1 indicates that the coordinate in that direction participates in the compensation; When the i direction is not the trigger direction, d i = 0, indicating that the coordinate in that direction is not included in the compensation; in the measurement mode where the moving component (B) moves along the X direction, d x =1,d y = 0, d z = 0; Step 5: Use the compensated trigger position coordinates calculated by equation (1) as the actual measurement point coordinates and use them for the calculation of subsequent measurement results to realize dynamic delay error compensation of the trigger probe.
3. The method for compensating for dynamic delay error of a trigger-type probe in a coordinate measuring machine according to claim 1, characterized in that, The triggering direction is one or more of the X, Y, and Z directions; the triggering direction coefficient d in equation (1) i Used to define the coordinate direction involved in compensation; when direction i is the trigger direction, d... i =1, when the i direction is a non-triggering direction, d i =0.
4. The method for compensating for dynamic delay error of a trigger-type probe in a coordinate measuring machine according to claim 1 or 2, characterized in that, The trigger position coordinates P2 during the approach phase and P2' during the retreat phase are both latched by the same data acquisition unit in the same trigger detection cycle.