A probe control method and device

Abstract

This application discloses a probe control method and apparatus. The probe control method includes the following steps: determining whether the probe has reached a preset position; if so, monitoring the feedback current of the drive motor and controlling the drive motor to move the probe; determining whether the feedback current of the drive motor has reached a preset feedback current; if so, controlling the drive motor to stop running, and the probe reaching the surface of the product to be processed. This application provides a probe control method and apparatus that monitors the pressure and position of the probe by monitoring the feedback current of the drive motor, avoiding excessively large puncture marks on the surface of the product to be processed, which could damage the product.

Description

Technical Field

[0001] This application relates to the field of printed circuit board testing technology, and more specifically, to a probe control method and apparatus. Background Technology

[0002] Printed circuit boards (PCBs) are prone to defects, necessitating inspection and repair. During inspection and repair, a drive motor moves a probe to the PCB surface so that conductive fluid can be sprayed onto it for repair. To prevent excessively large indentations from the probe on the PCB, which could damage the product quality after inspection and repair, the probe needs to be carefully controlled, especially its pressure and position.

[0003] Traditional methods for controlling probe pressure and position primarily rely on pressure sensors to detect the pressure signal fed back by the probe. However, due to the relatively low contact pressure between the probe and the printed circuit board (PCB), conventional pressure sensors lack the precision to accurately measure pressure and position, hindering precise pressure and position control and resulting in larger indentations on the PCB.

[0004] This issue also occurs in other product repair scenarios.

[0005] Therefore, how to improve the control accuracy of probe pressure and position has become a technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0006] This application provides a probe control method and apparatus, which can improve the control accuracy of probe pressure and position.

[0007] To solve one or more of the above-mentioned technical problems, the technical solution adopted in this application is:

[0008] This application provides a probe control method, including the following steps:

[0009] If the probe has reached the preset position, then the feedback current of the drive motor is monitored and the drive motor is controlled to move the probe.

[0010] Determine whether the feedback current of the drive motor reaches the preset feedback current. If so, control the drive motor to stop running, and the probe reaches the surface of the product to be processed.

[0011] Furthermore, before the probe reaches the preset position, the current position of the probe is determined by the pulse signal output by the grating ruler and the initial position of the probe, and the current position is used to determine whether the probe has reached the preset position.

[0012] Furthermore, the drive motor is controlled to move the probe at a first speed until the probe reaches the preset position; when the probe reaches the preset position, the drive motor is controlled to move the probe at a second speed until the current feedback current of the drive motor reaches the preset feedback current; the first speed is higher than the second speed.

[0013] Furthermore, the distance between the initial position of the probe and the product surface is a first distance, and the distance between the initial position of the probe and the preset position of the probe is a second distance, wherein the second distance is 50%-75% of the first distance. Preferably, the second distance is 60% of the first distance.

[0014] Furthermore, the preset feedback current corresponds to the probe reaching the product surface and maintaining a preset curvature on the product surface.

[0015] Furthermore, after a preset time has elapsed since the current feedback current of the drive motor reaches the preset feedback current, the drive motor is activated to move the probe away from the product surface. The preset time is 40-60 ms. Preferably, the preset time is 50 ms.

[0016] Furthermore, when the product to be processed is a defective product to be repaired, the method further includes:

[0017] When the current feedback current of the drive motor is determined to reach a preset feedback current, the probe is controlled to spray a conductive fluid onto the defective product for repair. The conductive fluid includes silver paste or copper paste, etc.

[0018] Furthermore, the drive motor includes at least one of a voice coil motor, a servo motor, or a stepper motor.

[0019] Corresponding to the above-described probe control method, this application also provides a probe control device, the device comprising:

[0020] The controller is used to monitor the current feedback current of the drive motor, and when it is determined that the current feedback current of the drive motor reaches the preset feedback current, the controller stops the operation of the drive motor.

[0021] A drive motor is used to move the probe under the control of the controller, and the preset feedback current corresponds to the probe reaching the surface of the product to be processed.

[0022] The grating ruler is used to output pulse signals and feed them back to the controller. The controller controls the emission of pulses, and by emitting a certain number of pulses, the probe can be controlled to move accurately to a preset position.

[0023] According to the specific embodiments provided in this application, the following technical effects are disclosed:

[0024] This application embodiment monitors the pressure and position of the probe by monitoring the feedback current of the drive motor. When it is determined that the current feedback current of the drive motor reaches the preset feedback current, the operation of the drive motor is stopped. Since the preset feedback current is related to the position and pressure of the probe, the probe can be accurately controlled to move to the surface of the product to be treated by setting the preset feedback current in the drive motor, and to contact the surface of the product to be treated and maintain a certain pressure so that the probe can spray conductive fluid and repair the product to be treated.

[0025] Furthermore, this embodiment divides the probe movement process into two stages. In the first stage, the drive motor is controlled to move the probe from the initial position to a preset position at a first speed. In the second stage, the drive motor is controlled to move the probe from the preset position at a second speed until the current feedback current of the drive motor reaches the preset feedback current, i.e., the probe moves to the surface of the product to be processed. Here, the second speed is less than the first speed. The faster movement speed in the first stage ensures higher work efficiency. In the second stage, the probe's movement speed is reduced to avoid difficulties in accurately controlling the probe pressure and position, thereby further avoiding excessively large puncture marks on the product to be processed and damage to the product. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 A flowchart of the probe control method provided in the embodiments of this application.

[0028] Figure 2 This is a schematic diagram of the probe control device provided in an embodiment of this application. Detailed Implementation

[0029] The technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art are within the scope of protection of this application.

[0030] The movement of the probe requires position monitoring to determine whether it has reached the product surface. If position monitoring is based on pressure, it only occurs after pressure is applied to the product surface, resulting in a lag. Therefore, the current problem to be solved is how to accurately monitor the probe's arrival at the product surface.

[0031] Current probes rely on a drive motor, such as a voice coil motor, for movement. The spring deformation of the drive motor corresponds to its feedback current, which in turn corresponds to the probe's movement distance; that is, the drive motor's feedback current is related to the probe's movement distance. Therefore, this application creatively proposes that a preset feedback current when the probe reaches the product surface can be obtained in advance. Then, during probe control, whether the drive motor's feedback current reaches the preset feedback current is used to determine whether the probe has moved to the product surface. Based on the accuracy and timeliness of current monitoring, this application can accurately and promptly determine whether the probe has moved to the product surface.

[0032] In summary, the methods include, for example: Figure 1 The steps shown are as follows:

[0033] S1: Determine whether the probe has reached the preset position. If so, start monitoring the feedback current of the drive motor and control the drive motor to move the probe.

[0034] S2: Determine whether the feedback current of the drive motor reaches the preset feedback current. If so, control the drive motor to stop running and the probe reaches the surface of the product to be processed.

[0035] Example 1

[0036] Current monitoring requires a high frequency of acquisition and judgment. However, it takes a certain amount of time for the probe to move from its initial position (when the probe is not in use, it needs to be in a certain position, and in the probe control device, the initial position generally corresponds to a fixed position) to the product surface. Therefore, relying on current monitoring for the whole process is a waste of resources. To address this, this application creatively selects a point between the probe's initial position and the product surface as a preset position, monitors the position between the initial position and the preset position using a grating ruler, and selects a more precise current monitoring between the preset position and the product surface.

[0037] Before the probe reaches the preset position, its current position is determined using the pulse signal output by the grating ruler and the probe's initial position. Specifically, the distance the probe needs to reach the preset position is converted into a specific number of pulses. Since one pulse corresponds to a certain distance, a certain number of pulses are used to control the probe's movement until it reaches the preset position. In this embodiment, the host computer controls the transmission of pulses; by transmitting a certain number of pulses, the probe can be controlled to move accurately to the preset position.

[0038] The feedback current corresponds to the spring deformation of the drive motor. To obtain the feedback current of the drive motor when the probe reaches the product surface, a preset feedback current needs to be determined through prior testing. When the probe is not in contact with the product surface, the current of the drive motor changes linearly with the movement of the probe. Based on the initial current value set for the drive motor, the probe is controlled to move from its initial position to the product surface. The magnitude of the feedback current when the probe contacts the product surface is recorded, and a puncture mark image is acquired. When the probe contacts the product surface, due to the force exerted by the probe during its movement, a puncture mark corresponding to the magnitude of the force is left on the product surface. By analyzing different puncture mark images, the required force can be determined, thereby further determining the required feedback current. By establishing the mapping relationship between the feedback current and the probe's downward movement distance, and by comparing the puncture mark images, the preset feedback current value can be obtained.

[0039] Furthermore, the probe needs to maintain a preset curvature on the product surface so that the probe can spray conductive fluid to repair the defective product. In practice, multiple repeated experiments can be conducted on various sampling points of the same product. The feedback current values ​​obtained from the multiple repeated experiments are then used as the average value, which is used as the preset feedback current of the product in the actual measurement process. Here, the preset feedback current corresponds to the probe reaching the product surface and maintaining a preset curvature on the product surface.

[0040] When the controller determines that the current feedback current of the drive motor has reached the preset feedback current, it controls the drive motor to stop moving. This ensures that the probe stops in time after contacting the product surface, so that the probe can be sprayed with conductive fluid to repair the product. It also further avoids the probe from creating excessively large puncture marks on the product.

[0041] In one specific implementation, the drive motor descends at a specified speed. During the descent, the controller activates its data acquisition function for the drive motor, collecting and recording the drive motor's position and the corresponding current feedback current value at each position according to a set sampling frequency. It should be noted that the descent speed of the drive motor is determined by its resolution and the sampling frequency. Because the controller collects current data at the set sampling frequency, it can determine whether the current feedback current has reached the preset feedback current. Upon determining that the feedback current has reached the preset feedback current, the controller stops the drive motor, meaning the probe stops descending.

[0042] In summary, the method includes, for example: Figure 1 The steps shown are as follows:

[0043] S0: Determine the current position of the probe using the pulse signal output by the grating ruler and the initial position of the probe, and determine whether the probe has reached the preset position based on the current position;

[0044] S1: Determine whether the probe has reached the preset position. If so, start monitoring the feedback current of the drive motor and control the drive motor to move the probe.

[0045] S2: Determine whether the feedback current of the drive motor reaches the preset feedback current. If so, control the drive motor to stop running and the probe reaches the surface of the product to be processed.

[0046] In this embodiment, the control of probe position and pressure is transformed into monitoring of the drive motor feedback current by considering the relationship between the distance between the probe and the product surface, the pressure, and the feedback current of the drive motor. When the feedback current of the drive motor reaches the preset feedback current, the probe can be accurately and promptly controlled to stop moving, so that the probe can spray conductive fluid or otherwise repair the product to be treated.

[0047] Example 2

[0048] Based on Example 1, this application implements phased control of the probe speed.

[0049] Because the distance between the probe and the product is short and the probe moves at a relatively high speed, it is easy to cause problems with controlling the contact pressure between the probe and the product. Simply reducing the probe speed to solve this problem would reduce the efficiency of the inspection and repair process. This application's embodiment divides the probe movement process into two stages:

[0050] In the first stage, the drive motor is controlled to move the probe at a first speed until the probe reaches the preset position;

[0051] In the second stage, when the probe reaches the preset position, the drive motor is controlled to move the probe at a second speed until the current feedback current of the drive motor reaches the preset feedback current. It should be noted that the first speed is higher than the second speed.

[0052] A preset position is set between the probe's initial position and the product surface, dividing the distance between them into two parts. The distance between the probe's initial position and the product surface is the first distance, and the distance between the probe's initial position and the preset position is the second distance, which also corresponds to the distance the probe travels in the second stage. In this embodiment, the second distance is 50%-75% of the first distance; more specifically, the second distance is 50%, 55%, 60%, 65%, 70%, and 75% of the first distance, preferably 60%, and other values ​​are not exhaustively listed here due to space limitations. It should be noted that, to ensure measurement accuracy, the probe needs to be calibrated to zero initially, establishing its absolute position relative to the zero point, i.e., calibrating the probe's initial position.

[0053] The first stage uses a relatively fast movement speed to ensure high working efficiency, with the probe moving at high speed to the preset position. In the second stage, when the probe reaches the preset position, the output current of the controller is limited to reduce the force of the drive motor, thereby reducing the probe's movement speed and preventing excessively large puncture marks on the product or damage to the product.

[0054] For the parts of Embodiment 2 that are not detailed, please refer to the descriptions in the foregoing embodiments, which will not be repeated here.

[0055] Example 3

[0056] Based on Embodiment 1 and Embodiment 2, in this embodiment of the application, when it is determined that the current feedback current of the drive motor reaches the preset feedback current, the control probe sprays conductive fluid onto the product for repair.

[0057] Some products, such as printed circuit boards, are prone to short circuits or open circuits in their connections during manufacturing due to equipment limitations. Directly scrapping such defective products would result in significant economic losses; therefore, repair is necessary. In practice, a probe is filled with a certain amount of conductive fluid. When the current feedback current of the drive motor reaches a preset feedback current, the probe is controlled to remain on the surface of the defective product for a preset time, allowing the conductive fluid to repair the short-circuited or open-circuited connections. The conductive fluid can be silver paste or copper paste, ensuring good conductivity. After the preset feedback current and preset time have elapsed, the drive motor is activated to move the probe away from the product surface, completing the repair process.

[0058] In order for the conductive fluid in the probe to effectively repair the short-circuited or open-circuited connection lines on the surface of the defective product, it is necessary to control the preset time for the probe to stay on the surface of the defective product. The preset time is 40-60ms, more specifically, the preset time is 40ms, 45ms, 50ms, 55ms and 60ms, preferably 50ms, and will not be listed exhaustively here due to space limitations.

[0059] For the parts of Embodiment 3 that are not detailed, please refer to the descriptions in the foregoing embodiments, which will not be repeated here.

[0060] Example 4

[0061] This application also provides a probe control device 10, such as Figure 2 As shown, the device includes:

[0062] The controller 101 is used to monitor the current feedback current of the drive motor 102, and when it is determined that the current feedback current of the drive motor 102 reaches the preset feedback current, the controller 101 stops the operation of the drive motor 102.

[0063] A drive motor 102 is used to drive the probe to move under the control of the controller 101, and the preset feedback current corresponds to the probe reaching the surface of the product to be processed.

[0064] The drive motor 102 is an electromagnetic device that converts or transmits electrical energy based on the law of electromagnetic induction. Its main function is to generate driving torque, serving as a power source for electrical appliances or various machines. The drive motor 102 includes at least one of a voice coil motor, a servo motor, or a stepper motor. As a preferred embodiment, in this application, the drive motor 102 is a voice coil motor. Voice coil motors have advantages such as simple structure, small size, high speed, and fast acceleration response, and are commonly used in positioning motion systems requiring high acceleration, high frequency response, and fast and high precision. In this application embodiment, the current feedback of the voice coil motor is used to control the distance of the probe's downward movement, which can control the probe to stop in time after contacting the product, thereby avoiding excessively large puncture marks on the product caused by the probe.

[0065] Corresponding to Embodiment 1, distance detection can be performed using a grating ruler 103. The control device also includes a grating ruler 103, which outputs pulse signals and feeds them back to the controller 101. The controller 101 controls the emission of pulses; by emitting a certain number of pulses, the probe can be controlled to move accurately to a preset position.

[0066] The foregoing has provided a detailed description of the probe control method and apparatus provided in this application. Specific examples have been used to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are merely for the purpose of helping to understand the method and its core ideas. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A probe control method characterized by, The method comprises the following steps: determining whether the probe reaches the preset position, if yes, monitoring the feedback current of the driving motor, and controlling the driving motor to drive the probe to move; determining whether the feedback current of the driving motor reaches the preset feedback current, if yes, controlling the driving motor to stop running, the probe reaches the surface of the product to be processed and keeps a preset bending degree, so as to spray the conductive fluid; wherein the feedback current is directly related to the spring deformation of the driving motor, and the preset feedback current is determined by pre-calibrating the indentation image when the probe contacts the surface of the product.

2. The probe control method according to claim 1, wherein The method further comprises: determining the current position of the probe by using the pulse signal output by the grating ruler and the initial position of the probe; determining whether the probe reaches the preset position according to the current position.

3. The probe control method according to claim 1, wherein The method further comprises: controlling the driving motor to drive the probe to move at a first speed until the probe reaches the preset position; controlling the driving motor to drive the probe to move at a second speed until the current feedback current of the driving motor reaches the preset feedback current when the probe reaches the preset position; The first speed is higher than the second speed.

4. The probe control method according to claim 2, wherein a distance between an initial position of the probe and the product surface is a first distance, a distance between the initial position of the probe and the preset position of the probe is a second distance, the second distance is 50% of the first distance 75%.

5. The probe control method according to claim 4, wherein The second distance is 60% of the first distance.

6. The probe control method of claim 1, wherein The preset feedback current corresponds to the probe reaching the surface of the product and keeping a preset bending degree on the surface of the product.

7. The probe control method according to claim 6, wherein The method further comprises: starting the driving motor to drive the probe away from the surface of the product after a preset time when the current feedback current of the driving motor reaches the preset feedback current; The preset time is 40 60 ms.

8. The probe control method of claim 1, wherein The product to be processed is a defective product to be repaired. The method further comprises: controlling the probe to spray the conductive fluid on the defective product for repair when it is determined that the current feedback current of the driving motor reaches the preset feedback current.

9. The probe control method of claim 1, wherein The driving motor comprises at least one of a voice coil motor, a servo motor or a stepping motor.

10. A probe control device, characterized by The device comprises: a controller for monitoring the current feedback current of the driving motor, and stopping the driving motor from running when it is determined that the current feedback current of the driving motor reaches the preset feedback current; a driving motor for driving the probe to move under the control of the controller; The preset feedback current corresponds to the probe reaching the surface of the product to be processed.

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