CN109459970B - A vision-based elliptical hole potentiometer angle reset system and reset method - Google Patents

Abstract

The invention provides an elliptical hole potentiometer angle resetting system and method based on vision, belongs to the technical field of elliptical hole potentiometer angle resetting, and particularly relates to an elliptical hole potentiometer angle resetting system and method based on vision. The problem of in the current electrical parameter testing process mainly adopt artifical mode to the angle resetting operation of elliptical aperture, with high costs, inefficiency, the accuracy also is difficult to guarantee for a long time is solved. The device comprises a PLC control system, a CAN bus, an angle detection device and an angle reset device, and simultaneously provides a corresponding reset method. The device is mainly used for resetting the angle of the elliptical hole potentiometer.

Description

A vision-based elliptical hole potentiometer angle reset system and reset method

technical field

The invention belongs to the technical field of angle reset of an oval hole potentiometer, in particular to a vision-based system and method for resetting the angle of an oval hole potentiometer.

Background technique

During the production process of the elliptical hole potentiometer, it is necessary to detect the electrical parameters such as zero resistance and sliding noise of the potentiometer. The detection steps are: first, rotate the elliptical hole clockwise to the initial position to detect zero resistance, and then turn the elliptical hole counterclockwise from the initial position. Rotate to end position to detect sliding noise. However, due to problems in the production process, the elliptical holes on the potentiometers produced on the assembly line are usually at any angle. At present, manufacturers mainly use manual methods to reset the angle of the elliptical hole during the electrical parameter testing process. When the potentiometer to be tested enters the fixture of the electrical parameter testing station, it is manually rotated to the initial position before testing. The manual reset method is not only costly and inefficient, but also difficult to guarantee accuracy for a long time.

Contents of the invention

In order to solve the problems in the prior art, the present invention proposes a vision-based elliptical hole potentiometer angle reset system and a reset method.

To achieve the above object, the present invention adopts the following technical solutions: a vision-based elliptical hole potentiometer angle reset system, which includes a PLC control system, a CAN bus, an angle detection device and an angle reset device, the PLC control system and the CAN bus Communication connection, the angle detection device includes a camera and an industrial computer, the camera is installed directly above the potentiometer fixture to be detected, the camera is connected to the industrial computer through Gigabit Ethernet, and the industrial computer communicates with the industrial computer through the RS485 module PLC control system communication connection, the angle reset device includes a cylinder, a servo motor and a batch head, the telescopic rod of the cylinder is connected to the servo motor, the output shaft of the servo motor is fixedly connected to the batch head, and the servo motor is connected to the CAN bus Communication connection, the cylinder communicates with the CAN bus through the I/O module, the angle reset device is located directly above the potentiometer fixture to be reset, the area where the angle detection device is located is the angle detection station, and the angle reset The area where the device is located is the angle reset station.

Furthermore, the bit has an elliptical structure.

The present invention also provides a method for resetting the angle of the oval hole potentiometer based on vision, which includes the following steps:

Step 1: When the potentiometer enters the fixture of the angle detection station, the PLC control system sends an angle detection station ready signal to the industrial computer through the RS485 module;

Step 2: After the industrial computer obtains the ready signal of the angle detection station, it sends a trigger signal to the camera through Gigabit Ethernet;

Step 3: After the camera obtains the trigger signal, it takes an image, and transmits the captured image to the industrial computer through Gigabit Ethernet;

Step 4: After the industrial computer obtains the image, calculate the deflection angle of the elliptical hole according to the angle detection algorithm, and send the deflection angle to the PLC control system through the RS485 module;

Step 5: After the PLC control system obtains the deflection angle of the elliptical hole, it transmits the deflection angle to the servo motor in the angle reset device through the CAN bus, and at the same time notifies the potentiometer transmission mechanism through the CAN bus to transmit the potentiometer to the angle reset station;

Step 6: After the servo motor in the angle reset device obtains the deflection angle, the servo motor rotates counterclockwise from the initial position to the deflection angle, and after the rotation is completed, a servo motor ready signal is sent to the PLC control system through the CAN bus;

Step 7: After the potentiometer enters the fixture of the angle reset station, an angle reset station ready signal is sent to the PLC control system through the CAN bus;

Step 8: After the PLC control system receives the servo motor ready signal and the angle reset station ready signal at the same time, it transmits the trigger signal to the cylinder through the CAN bus;

Step 9: After the cylinder receives the trigger signal, it moves downward from the high position to the low position, so that the bit enters the oval hole, and then sends a cylinder extension signal to the PLC control system through the CAN bus;

Step 10: After the PLC control system receives the cylinder extension signal, it sends the trigger signal to the servo motor through the CAN bus;

Step 11: After receiving the trigger signal, the servo motor rotates the deflection angle received in step 6 clockwise to make the oval hole rotate to the initial position, and then sends an angle reset completion signal to the PLC control system through the CAN bus;

Step 12: After receiving the angle reset signal, the PLC control system notifies the cylinder to move from the low position to the high position through the CAN bus, and notifies the servo motor to rotate to the initial position, and at the same time notifies the potentiometer transmission mechanism to transmit the potentiometer to the electrical parameter detection Station.

Further, the angle detection algorithm includes the following steps:

Step 1: From the center of the image captured by the camera of the angle detection device, intercept a square image sub-block with a size of 700×700 pixels as the input image of the detection algorithm;

Step 2: Extract the white channel of the input image in the color name space, and normalize it to the [0,1] interval;

Step 3: In the normalized image, the 8-connected method is used to remove the foreground area that is brighter than the surrounding and connected to the image boundary;

Step 4: Construct a disk-shaped structure with a radius of 10, and use this structure to perform an erosion operation on the image after removing the boundary area;

Step 5: Use the corroded image as a marked image, and use the image after clearing the boundary area as a mask image, perform morphological reconstruction, and remove the foreground area outside the elliptical hole area that is brighter than the surrounding area;

Step 6: Normalize the morphologically reconstructed image to the [0,1] interval, and perform a binarization operation with a threshold of 0.5 to obtain a binary image containing only the elliptical hole area;

Step 7: Calculate the centroid coordinates [x ₀ ,y ₀ ] and the main axis angle α∈[0°,180°] two descriptors of the elliptical hole area in the binary image, and use the above two descriptors to obtain the passing coordinate point [ x ₀ ,y ₀ ], the linear equation of the main axis with angle α;

Step 8: Use the Sobel operator to perform edge detection on the binary image containing the elliptical hole area, and obtain the coordinates of each pixel on the edge of the elliptical hole area;

Step 9: Calculate the distance from the coordinates of each pixel point on the edge to the main axis line, and the point with the largest distance is the sharp point of the gap, and the coordinates of this point are marked as [x _p , y _p ];

Step 10: Use the centroid coordinates [x ₀ , y ₀ ] of the elliptical hole area, the main axis angle α, and the notch cusp coordinates [x _p , y _p ] to calculate the deflection angle β of the elliptical hole. The calculation formula is:

Among them, α ₀ is the main axis angle of the initial position of the standard component of the oval hole potentiometer.

Further, the calculation process of _α0 in the angle detection algorithm comprises the following steps:

Step 1: Manually rotate the elliptical hole in the standard component of the elliptical hole potentiometer to the initial position, and put it into the fixture of the angle detection station;

Step 2: Take an image through the camera of the angle detection device;

Step 3: Calculate the main axis angle of the elliptical hole by using the methods described in steps 1 to 7 of the angle detection algorithm, and the obtained main axis angle is α ₀ .

Compared with the prior art, the beneficial effect of the present invention is: the present invention uses the image trigger acquisition module to collect the image information of the elliptical hole potentiometer to be detected, and through the defined angle detection algorithm, the angle reset device is used to realize the adjustment of the elliptical hole potentiometer. Automatic angle reset operation; significantly reduce the cost of manual reset, increase the accuracy of angle reset, improve detection efficiency, small investment, easy to operate, and have great market prospects.

Description of drawings

Fig. 1 is a kind of vision-based elliptical hole potentiometer angle reset system structure schematic diagram according to the present invention

Fig. 2 is a flow chart of a method for resetting the angle of an elliptical hole potentiometer based on vision according to the present invention

Fig. 3 is a schematic diagram of the elliptical hole potentiometer collected by a vision-based elliptical hole potentiometer angle reset method according to the present invention

Fig. 4 is a schematic diagram of the initial position of the elliptical hole angle collected by a vision-based elliptical hole potentiometer angle reset method according to the present invention

Fig. 5 is a schematic diagram of the end position of the elliptical hole angle collected by a vision-based elliptical hole potentiometer angle reset method according to the present invention

Figure 6 is a schematic diagram of the result of extracting and normalizing the white channel in the color name space in Figure 4

Figure 7 is a schematic diagram of the result of clearing the boundary area in Figure 6

Figure 8 is a schematic diagram of the results of morphological reconstruction in Figure 7

Figure 9 is a schematic diagram of the results of normalization and binarization in Figure 8

Figure 10 is a schematic diagram of the result of edge detection in Figure 9

Fig. 11 is a schematic diagram of the initial position main axis angle α ₀ obtained by the angle detection algorithm of the present invention

Fig. 12 is a schematic diagram of the deflection angle β of the elliptical hole in Fig. 3 obtained by the angle detection algorithm of the present invention

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention.

Referring to Figures 1-12 to illustrate this embodiment, a vision-based elliptical hole potentiometer angle reset system includes a PLC control system, a CAN bus, an angle detection device and an angle reset device, and the PLC control system is connected to the CAN bus for communication , the angle detection device includes a camera and an industrial computer, the camera is installed directly above the potentiometer fixture to be detected, the camera is connected to the industrial computer through Gigabit Ethernet, and the industrial computer is controlled by the RS485 module and the PLC System communication connection, the angle reset device includes a cylinder, a servo motor and a bit, the telescopic rod of the cylinder is connected to the servo motor, the output shaft of the servo motor is fixedly connected to the bit, and the servo motor is connected to the CAN bus , the cylinder communicates with the CAN bus through an I/O module, the angle reset device is located directly above the potentiometer fixture to be reset, the area where the angle detection device is located is an angle detection station, and the angle reset device is located The area is the angle reset station.

The bit has an elliptical structure, which is convenient for the bit to enter into the elliptical hole and reset the elliptical hole.

The present invention simultaneously provides a kind of vision-based method for resetting the angle of the elliptical hole potentiometer, which includes the following steps:

Step 1: When the potentiometer enters the fixture of the angle detection station, the PLC control system sends an angle detection station ready signal to the industrial computer through the RS485 module;

Step 2: After the industrial computer obtains the ready signal of the angle detection station, it sends a trigger signal to the camera through Gigabit Ethernet;

Step 3: After the camera obtains the trigger signal, it takes an image, and transmits the captured image to the industrial computer through Gigabit Ethernet;

Step 4: After the industrial computer obtains the image, calculate the deflection angle of the elliptical hole according to the angle detection algorithm, and send the deflection angle to the PLC control system through the RS485 module;

Step 5: After the PLC control system obtains the deflection angle of the elliptical hole, it transmits the deflection angle to the servo motor in the angle reset device through the CAN bus, and at the same time notifies the potentiometer transmission mechanism through the CAN bus to transmit the potentiometer to the angle reset station;

Step 6: After the servo motor in the angle reset device obtains the deflection angle, the servo motor rotates counterclockwise from the initial position to the deflection angle, and after the rotation is completed, a servo motor ready signal is sent to the PLC control system through the CAN bus;

Step 7: After the potentiometer enters the fixture of the angle reset station, an angle reset station ready signal is sent to the PLC control system through the CAN bus;

Step 8: After the PLC control system receives the servo motor ready signal and the angle reset station ready signal at the same time, it transmits the trigger signal to the cylinder through the CAN bus;

Step 9: After the cylinder receives the trigger signal, it moves downward from the high position to the low position, so that the bit enters the oval hole, and then sends a cylinder extension signal to the PLC control system through the CAN bus;

Step 10: After the PLC control system receives the cylinder extension signal, it sends the trigger signal to the servo motor through the CAN bus;

Step 11: After receiving the trigger signal, the servo motor rotates the deflection angle received in step 6 clockwise to make the oval hole rotate to the initial position, and then sends an angle reset completion signal to the PLC control system through the CAN bus;

Step 12: After receiving the angle reset signal, the PLC control system notifies the cylinder to move from the low position to the high position through the CAN bus, and notifies the servo motor to rotate to the initial position, and at the same time notifies the potentiometer transmission mechanism to transmit the potentiometer to the electrical parameter detection Station.

The angle detection algorithm includes the following steps:

Step 1: From the center of the image captured by the camera of the angle detection device, intercept a square image sub-block with a size of 700×700 pixels as the input image of the detection algorithm;

Step 2: Extract the white channel of the input image in the color name space, and normalize it to the [0,1] interval;

Step 3: In the normalized image, the 8-connected method is used to remove the foreground area that is brighter than the surrounding and connected to the image boundary;

Step 4: Construct a disk-shaped structure with a radius of 10, and use this structure to perform an erosion operation on the image after removing the boundary area;

Step 5: Use the corroded image as a marked image, and use the image after clearing the boundary area as a mask image, perform morphological reconstruction, and remove the foreground area outside the elliptical hole area that is brighter than the surrounding area;

Step 6: Normalize the morphologically reconstructed image to the [0,1] interval, and perform a binarization operation with a threshold of 0.5 to obtain a binary image containing only the elliptical hole area;

Step 7: Calculate the centroid coordinates [x ₀ ,y ₀ ] and the main axis angle α∈[0°,180°] two descriptors of the elliptical hole area in the binary image, and use the above two descriptors to obtain the passing coordinate point [ x ₀ ,y ₀ ], the linear equation of the main axis with angle α;

Step 8: Use the Sobel operator to perform edge detection on the binary image containing the elliptical hole area, and obtain the coordinates of each pixel on the edge of the elliptical hole area;

Step 9: Calculate the distance from the coordinates of each pixel point on the edge to the main axis line, and the point with the largest distance is the sharp point of the gap, and the coordinates of this point are marked as [x _p , y _p ];

Step 10: Use the centroid coordinates [x ₀ , y ₀ ] of the elliptical hole area, the main axis angle α, and the notch cusp coordinates [x _p , y _p ] to calculate the deflection angle β of the elliptical hole. The calculation formula is:

Among them, α ₀ is the main axis angle of the initial position of the standard component of the oval hole potentiometer.

The calculation process of _α0 in the angle detection algorithm includes the following steps:

Step 1: Manually rotate the elliptical hole in the standard component of the elliptical hole potentiometer to the initial position, and put it into the fixture of the angle detection station;

Step 2: Take an image through the camera of the angle detection device;

Step 3: Calculate the main axis angle of the elliptical hole by using the methods described in steps 1 to 7 of the angle detection algorithm, and the obtained main axis angle is α ₀ .

The vision-based elliptical hole potentiometer angle reset system and reset method provided by the present invention have been introduced in detail above. In this paper, specific examples have been used to illustrate the principle and implementation of the present invention. The description of the above embodiments It is only used to help understand the method of the present invention and its core idea; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation and scope of application. In summary, The contents of this description should not be construed as limiting the present invention.

Claims (3)

1. a kind of reset method based on the oval hole potentiometer angle reset system of vision, described reset system comprises PLC control system, CAN bus, angle detection device and angle reset device, described PLC control system is connected with CAN bus communication, so The angle detection device includes a camera and an industrial computer, the camera is installed directly above the potentiometer fixture to be detected, the camera is connected to the industrial computer through Gigabit Ethernet, and the industrial computer communicates with the PLC control system through the RS485 module connection, the angle reset device includes a cylinder, a servo motor and a bit, the telescopic rod of the cylinder is connected to the servo motor, the output shaft of the servo motor is fixedly connected to the bit, and the servo motor is connected to the CAN bus communication, the The cylinder is communicated with the CAN bus through an I/O module, the angle reset device is located directly above the potentiometer fixture to be reset, the area where the angle detection device is located is an angle detection station, and the area where the angle reset device is located It is an angle reset station, characterized in that: the reset method includes the following steps: Step 1: When the potentiometer enters the fixture of the angle detection station, the PLC control system sends an angle detection station ready signal to the industrial computer through the RS485 module; Step 2: After the industrial computer obtains the ready signal of the angle detection station, it sends a trigger signal to the camera through Gigabit Ethernet; Step 3: After the camera obtains the trigger signal, it takes an image, and transmits the captured image to the industrial computer through Gigabit Ethernet; Step 4: After the industrial computer obtains the image, calculate the deflection angle of the elliptical hole according to the angle detection algorithm, and send the deflection angle to the PLC control system through the RS485 module; Step 5: After the PLC control system obtains the deflection angle of the elliptical hole, it transmits the deflection angle to the servo motor in the angle reset device through the CAN bus, and at the same time notifies the potentiometer transmission mechanism through the CAN bus to transmit the potentiometer to the angle reset station; Step 6: After the servo motor in the angle reset device obtains the deflection angle, the servo motor rotates counterclockwise from the initial position to the deflection angle, and after the rotation is completed, a servo motor ready signal is sent to the PLC control system through the CAN bus; Step 7: After the potentiometer enters the fixture of the angle reset station, an angle reset station ready signal is sent to the PLC control system through the CAN bus; Step 8: After the PLC control system receives the servo motor ready signal and the angle reset station ready signal at the same time, it transmits the trigger signal to the cylinder through the CAN bus; Step 9: After the cylinder receives the trigger signal, it moves downward from the high position to the low position, so that the bit enters the oval hole, and then sends a cylinder extension signal to the PLC control system through the CAN bus; Step 10: After the PLC control system receives the cylinder extension signal, it sends the trigger signal to the servo motor through the CAN bus; Step 11: After receiving the trigger signal, the servo motor rotates the deflection angle received in step 6 clockwise to make the oval hole rotate to the initial position, and then sends an angle reset completion signal to the PLC control system through the CAN bus; Step 12: After receiving the angle reset signal, the PLC control system notifies the cylinder to move from the low position to the high position through the CAN bus, and notifies the servo motor to rotate to the initial position, and at the same time notifies the potentiometer transmission mechanism to transmit the potentiometer to the electrical parameter detection Station, The angle detection algorithm comprises the following steps: Step 1: From the center of the image captured by the camera of the angle detection device, intercept a square image sub-block with a size of 700×700 pixels as the input image of the detection algorithm; Step 2: Extract the white channel of the input image in the color name space, and normalize it to the [0,1] interval; Step 3: In the normalized image, the 8-connected method is used to remove the foreground area that is brighter than the surrounding and connected to the image boundary; Step 4: Construct a disk-shaped structure with a radius of 10, and use this structure to perform an erosion operation on the image after removing the boundary area; Step 5: Use the corroded image as a marked image, and use the image after clearing the boundary area as a mask image, perform morphological reconstruction, and remove the foreground area outside the elliptical hole area that is brighter than the surrounding area; Step 6: Normalize the morphologically reconstructed image to the [0,1] interval, and perform a binarization operation with a threshold of 0.5 to obtain a binary image containing only the elliptical hole area; Step 7: Calculate the centroid coordinates [x ₀ ,y ₀ ] and the main axis angle α∈[0°,180°] two descriptors of the elliptical hole area in the binary image, and use the above two descriptors to obtain the passing coordinate point [ x ₀ ,y ₀ ], the linear equation of the main axis with angle α; Step 8: Use the Sobel operator to perform edge detection on the binary image containing the elliptical hole area, and obtain the coordinates of each pixel on the edge of the elliptical hole area; Step 9: Calculate the distance from the coordinates of each pixel point on the edge to the main axis line, and the point with the largest distance is the sharp point of the gap, and the coordinates of this point are marked as [x _p , y _p ]; Step 10: Use the centroid coordinates [x ₀ , y ₀ ] of the elliptical hole area, the main axis angle α, and the notch cusp coordinates [x _p , y _p ] to calculate the deflection angle β of the elliptical hole. The calculation formula is: Among them, α ₀ is the main axis angle of the initial position of the standard component of the oval hole potentiometer. 2. the reset method of a kind of oval hole potentiometer angle reset system based on vision according to claim 1, is characterized in that: the calculation process of α ₀ in the described angle detection algorithm comprises the following steps: Step 1: Manually rotate the elliptical hole in the standard component of the elliptical hole potentiometer to the initial position, and put it into the fixture of the angle detection station; Step 2: Take an image through the camera of the angle detection device; Step 3: Calculate the main axis angle of the elliptical hole by using the methods described in steps 1 to 7 of the angle detection algorithm, and the obtained main axis angle is α ₀ . 3. A vision-based reset method for an elliptical hole potentiometer angle reset system according to claim 1, characterized in that: the bit is an elliptical structure.