System designated purpose is to monitor the turbocharger subassemblies made by the operator, to record typical errors in assembling the turbocharger given in the initial conditions of the control task.
The initial task of the contest of developing the technology for controlling manual operations was the creation of a system that allows diagnosing in real time the correct assembly of the turbocharger components and recognizing typical assembly errors by the provided assembly process.
In the course of the contest, we developed an object classifier that allows us to classify the turbocharger elements with high accuracy in accordance with the CAD models on the image and determine the coordinates of the elements in the image.
To solve this problem, there are several basic methods of solution:
The first option was chosen to participate in the contest, because during the first stages of the competition the implementation of the control of the object position allowed to most accurately solve the problem of localizing the position of objects. In the future, the classifier created to control the position of objects was used to control the presence of turbocharger components in assemblies.
The competition consisted of three stages:
Finally, our company has developed and demonstrated an application, which allows you to perform a full cycle of automatic control of assembly operations with minimal operator involvement. The application was based on the developed classifier, which was used to pass the first and second stages of the competition.
The developed classifier was built on the basis of a convolution neural network of in-depth training. For its training, both real images of the details of the turbocharger and virtual images obtained by rendering of CAD models were used. The operations of distortion of the original data were performed rotation for all images such as rotation, perspective transformation, noise, which allowed to obtain a stable recognition of the class and position of the object regardless of the viewing angles and the environment of the objects.
15 classes of source objects are used for recognition in the basic version of the classifier, the technical capabilities of the classifier allow simultaneous classification and recognition of several thousand classes.
a. Microsoft HoloLens
b. Epson Moverio
Application of the developed solution can be used in the areas of technical vision as:
1. Microscopy – counting and segmentation of objects having a form or color that is difficult to parameterize.
2. Electronics – localization of the position of the elements on the board or layout. One of the applications can be an electronic transfer system that calculates positions on a video image, captures and transfers an electronic component.
3. Industrial control systems – performing the classification and localization of the recognized object, for example:
a. Control of the labeled product class on the product.
b. Counting objects of a certain class in the image (for example, calculating the number and position of the parts in the image).
c. …
The first stage is to find the elements necessary for assembly
At this step, the necessary elements in the camera control zone are checked.
If any of the elements were not found, a message is displayed that this element is not in the control zone.
Recognition is performed regardless of the location of the element – for example, the compressor casing can be recognized regardless of the current rotation or movement relative to the camera.
Recognizable items:
1. Compressor wheel
2. Screen turbines
3. Bearing housing
4. Compressor housing
5. Rotor
6. Turbine
The second stage is the assembly of the rotor and the compressor wheel
At this stage, the search is made for an assembly consisting of the compressor wheel and the rotor.
The turquoise frames with captions highlight the elements necessary for assembly of the unit.
In the center of the screen, a red frame displays the control area, in which the presence of the assembled unit is checked. When the unit is recognized, the area containing the unit is highlighted with a blue frame and the control frame changes its color to green, which informs the operator about the correct assembly of the unit.
The assembly consists of a compressor wheel mounted on the rotor.
The third stage – unit assembly No. 1
At this stage, the assembly of the unit No. 1 consisting of a screen of a turbine, a rotor and a bearing housing is made.
The task of the operator at this stage is the correct assembly of the unit.
The turquoise frames with captions highlight the elements necessary for assembly of the units.
At the beginning of the video recording of this stage, an incorrect assembly of the unit is shown, leading to a typical error – uninstalled turbine screen. If the assembly is incorrect, the system recognizes the error and displays a message about incorrect assembly.
After the correct assembly of the unit and the correct installation of the turbine screen, the unit starts to be recognized. When the unit is recognized, the area containing the unit is highlighted with a blue frame and the control frame changes its color to green, which informs the operator about the correct assembly of the unit.
The fourth stage – unit assembly No. 2
At this stage, the assembly of the unit No. 2, consisting of the assembled unit No. 1 and the compressor cover, is demonstrated.
If the operator has not installed the compressor cover to the unit No. 1, there will be no transition to further assembly steps.
After the lid is installed in the unit No. 1 and the assembled element is located in the control zone (under the red frame), the system will recognize the element and allow the operator to make the next assembly step. After recognizing the element, the control frame will be colored green and the found element will be highlighted by a blue frame.
The fifth stage – unit assembly No. 3
The task of the operator at this stage is the correct installation of the compressor wheel on the rotor of the unit No. 2. If the compressor wheel is not installed, or is set incorrectly, an error message displays.
After correct installation of the compressor and orientation of the assembled unit vertically, the control frame will be colored green and the recognized element will be highlighted by a blue frame.
The sixth stage – unit assembly No.4
At this stage, the compressor casing is mounted on the assembled unit No.3.
The turquoise frame with the text highlights the compressor cover, as it is necessary to complete the assembly. After the compressor cover is installed on the assembled unit No.3, and the location of the unit in the control zone, the control frame will be colored green, meaning successful recognition of the assembled element. The blue border will indicate the area containing the assembled unit.
The seventh stage – assembly of turbocharger
At the final stage of the assembly, the unit No.4 and the turbine compressor are connected.
The turbine of the compressor is installed on the assembled unit No. 4. After the assembled turbocharger is located in the control zone and recognition, the control frame will be colored green and a message will be displayed on the successful completion of the turbocharger assembly.
