CN105068139A - Detection technology for mounting condition of piston cooling nozzle - Google Patents

Abstract

The invention discloses a detection process for the installation state of the piston cooling nozzle. After the engine is put in place, the camera is driven to the set position by the robot, and then the piston cooling nozzle installed in the engine cylinder body is photographed, and the visual software recognizes the photo. And compare it with the preset data, so as to detect whether the installation status of the piston cooling nozzle is qualified. The invention adopts visual detection technology to ensure the accuracy of detection and the correctness of detection results; cancels manual detection, reduces labor costs; optimizes the detection process, cancels operations such as rotating the crankshaft, and improves detection efficiency; uses a robot as the actuator of the camera, with high flexibility, It is suitable for the detection of the installation state of piston cooling nozzles of engines with various varieties and structures.

Description

A detection process of the installation state of the piston cooling nozzle

technical field

The invention belongs to the technical field of engine assembly, and in particular relates to a detection process for the installation state of a piston cooling nozzle.

Background technique

The piston cooling nozzle is a part installed in the engine cylinder to cool the piston. Usually the finished piston cooling nozzles rely on manual inspection. Manual visual inspection of the installation state of the piston cooling nozzle has three main disadvantages: First, the piston cooling nozzle is located inside the cylinder block, the manual detection error is relatively large, and it is easy to cause visual fatigue, and it cannot ensure that the piston does not contact the piston cooling nozzle during operation. In the event of a collision, there is a risk of damage to parts such as pistons and piston cooling nozzles; second, the cost of manual inspection is high; third, operations such as rotating the crankshaft are required, and the efficiency is low. And once the piston cooling nozzle is missing, it will lead to poor cooling of the piston, which will easily cause cylinder scuffing. However, if this type of problem is discovered during the test run, it will cause a large rework cost. Therefore, there is an urgent need for an effective means to detect the installation quality of the piston cooling nozzle.

Contents of the invention

The purpose of the invention is to solve the deficiency of manually detecting the installation state of the piston cooling nozzle. Through the automatic and high-precision detection of the equipment, the correctness of the detection results is ensured; the labor cost is reduced by canceling the detection of the operator or inspector; and the detection efficiency is improved by optimizing the detection process.

In order to achieve the above object, the present invention adopts the following technical solutions:

A detection process for the installation state of a piston cooling nozzle, characterized in that it comprises the following steps:

a. The engine enters the working position of the line body and stops;

b. The RFID tag or scanning gun gives the engine model signal and transmits it to the PLC;

c. According to the engine model obtained in step b, set the robot motion trajectory program;

d. PLC processes the engine model signal and triggers the robot to follow the trajectory program of the corresponding model;

e. The robot drives the camera to the corresponding position and triggers the camera to take pictures to obtain the internal picture of the engine cylinder block;

f. The visual program recognizes the internal picture of the engine cylinder block, and converts the installation state of the piston cooling nozzle into image elements that can be recognized by the visual program;

g. The vision program compares the image elements identified in step f with the stored image elements inside the cylinder block, and automatically judges whether it is qualified; if qualified, the robot drives the camera to continue to take pictures at the next position; if unqualified, it will be unqualified The location is recorded and stored, and then the next location is photographed;

h. The robot resets after taking pictures of all positions;

i. Generate the test result, and the man-machine interface will automatically prompt the test result; if it is qualified, go directly to the next step; if it is unqualified, confirm or adjust the installation status until it is qualified;

j. Complete the detection, start the line body, and the engine will flow away;

k.a~j step cycle.

It is further characterized in that: the specific steps of identifying image elements and judging qualified in the steps f and g are:

f1. The vision program calls the vision tool to fit the feature points of the main bearing hole A into a circle, and determine the relative position of the center of the circle in the entire picture, and then establish a coordinate system with the center of the circle as the origin;

f2. The visual program calls the visual tool to fit the feature points of the main bearing hole B into a circle, and obtain the coordinates of the center of the circle, and then establish a straight line 1 connecting the two main bearing holes;

f3. The visual program calls the visual tool to fit the feature points of the high and bright part of the piston cooling nozzle rod into a straight line, forming a straight line 2;

f4. Calculate the angle θ formed by the intersection of straight line 1 and straight line 2;

f5. The vision program calls the vision tool to fit the feature points on the edge of the piston cooling nozzle head into a circle, and obtain the O coordinate of the center of the circle;

f6. Calculate the vertical distance h from the center O to the straight line 1;

f7. Compare the included angle θ and distance h with the set range to determine the correctness of the installation of the piston cooling nozzle.

Further: In the step e, the camera takes pictures, and when acquiring the internal picture of the engine, it is illuminated by an auxiliary light source.

The calculation of the vertical distance in step f6 is obtained by multiplying the pixel value from the circle center O to the line 1 found in the picture by the resolution.

The engine has six cylinders each provided with a piston cooling nozzle.

The present invention has the following beneficial effects:

1. Adopt visual inspection technology to ensure the detection accuracy and the correctness of the detection results;

2. Cancel manual inspection and reduce labor cost;

3. Optimize the detection process, cancel operations such as rotating the crankshaft, and improve detection efficiency;

4. The robot is used as the actuator of the camera, which is highly flexible and suitable for the inspection of the installation status of piston cooling nozzles of various types and structures.

Description of drawings

Fig. 1 is a schematic diagram of the detection principle of the present invention.

Fig. 2 is a flow chart of the method of the present invention.

Detailed ways

A detection process for the installation state of the piston cooling nozzle is characterized in that the detection process includes the following steps:

a. The engine enters the working position of the line body and stops;

b. The RFID tag or scanning gun gives the engine model signal and transmits it to the PLC;

c. According to the engine type obtained in step b, set the robot trajectory program of the engine type;

d. PLC processes the engine model signal and triggers the robot to follow the trajectory program of the corresponding model;

e. The robot drives the camera to the corresponding position and triggers the camera to take pictures. The camera uses lenses, light sources, etc. to assist in taking pictures, so as to obtain a suitable internal picture of the engine cylinder block;

f. The vision program calls the vision tool to fit the feature points of the main bearing hole A into a circle, and determine the relative position of the center of the circle in the entire picture, and then establish a coordinate system with the center of the circle as the origin;

g. The vision program calls the vision tool to fit the feature points of the main bearing hole B into a circle, and obtain the coordinates of the center of the circle, and then establish a straight line 1 connecting the two main bearing holes;

h. The visual program calls the visual tool to fit the feature points of the high and bright part of the piston cooling nozzle rod into a straight line, forming a straight line 2;

i. Calculate the angle θ formed by the intersection of straight line 1 and straight line 2;

j. The vision program calls the vision tool to fit the feature points on the edge of the piston cooling nozzle head into a circle, and obtain the O coordinate of the center of the circle;

k. Obtain the vertical distance h from the center of the circle O to the line 1 by multiplying the pixel value from the center of the circle O to the line 1 found in the picture by the resolution;

l. Compare the included angle θ, distance h with the set range, and both are considered qualified within the range; if qualified, the robot continues to the next position to take pictures; if unqualified, record and store the unqualified parts , and then take pictures at the next location;

m. The robot resets after taking pictures of all positions;

n. Generate the test result, and the human-machine interface will automatically prompt the test result; if it is qualified, go directly to the next step; if it is not qualified, confirm or adjust the installation status until it is qualified;

o. After the inspection is completed, the line body starts and the engine flows away;

a~o step cycle.

Claims (5)

1. a characterization processes for piston cooling nozzle installment state, is characterized in that comprising the steps:

A. engine enters into line body running position and stops;

B.RFID label or scanner provide engine model signal and are transferred to PLC;

C. according to the engine model that step b obtains, setting robot motion track program;

D.PLC process engine model signal also triggers the track program that corresponding type is walked by robot;

E. robot drive camera is gone to corresponding position and is triggered camera and takes pictures, and obtains engine cylinder block intra pictures;

F. vision procedure identification engine cylinder block intra pictures, converts the image-element that vision program can identify to by piston cooling nozzle installment state;

G. the cylinder block internal image key element of the image-element that identified by step f of vision program and storage compares, and whether automatic decision is qualified; If qualified, robot drives camera to continue to walk next position and takes pictures; If defective, then defective position recorded and store, then carrying out next position and take pictures;

H. all positions take pictures after robot reset;

I. generate testing result, man-machine interface carries out testing result prompting automatically; If qualified, directly enter next step; If defective, then carry out installment state confirmation or adjustment, till qualified;

J. complete detection, line body starts, and engine flows away;

K.a ~ j step cycle.

2. the characterization processes of piston cooling nozzle installment state according to claim 1, is characterized in that: recognition image key element and judge that whether qualified concrete steps are in described step f, g:

F1. main bearing hole A unique point is fitted to a circle by vision routine call vision aid, and determines the relative position of the center of circle in whole picture, then sets up coordinate system using the center of circle as initial point;

F2. main bearing hole B unique point is fitted to a circle by vision routine call vision aid, and obtains central coordinate of circle, then sets up two main bearing hole line of centres straight lines 1;

F3. highlighted for piston cooling nozzle shaft Partial Feature point is fitted to straight line by vision routine call vision aid, forms straight line 2;

F4. the angle theta that intersects to form of calculated line 1 and straight line 2;

F5. piston cooling nozzle head edge unique point is fitted to a circle by vision routine call vision aid, and obtains center of circle O coordinate;

F6. the vertical range h of center of circle O to straight line 1 is calculated;

F7. angle theta, distance h and setting range are compared, determine the correctness that piston cooling nozzle is installed.

3. the characterization processes of piston cooling nozzle installment state according to claim 1, is characterized in that: in described step e, camera is taken pictures, and is thrown light on when obtaining engine interior picture by secondary light source.

4. the characterization processes of piston cooling nozzle installment state according to claim 2, is characterized in that: in described step f6, the calculating of vertical range is multiplied by resolution by the center of circle O that finds in picture to the pixel value of straight line 1 and is obtained.

5. the characterization processes of the piston cooling nozzle installment state according to any one of claim 1 ~ 4, is characterized in that: described engine has six cylinders, and each cylinder is provided with a piston cooling nozzle.