The section briefly describes the developed autonomous vision sensor-actuator-based circumferential seam path tracker welding machine. We have used SolidWorks software to design the two-dimensional (2D) and three-dimensional (3D) models of the machine. Figures 1–9 illustrate the various 2D and 3D views of the machine. Table 2 reveals the part number and name of the various components of a machine. The present work relates to a welding machine. More specifically, it shows an autonomous vision sensor-actuator-based circumferential seam path tracker welding machine (1000) capable of tracking a seam path of the cylindrical workpiece (101) for performing MIG welding operations in an automated way. In an embodiment of the present machine, the cylindrical workpiece (101) is an LPG cylinder. However, it should be emphasized that the present work is not limited to welding operation in the LPG cylinder (101). The inventive aspects, along with various components and engineering involved, will now be explained with reference to Figs. 1–9 herein.
Referring to Fig. 1, the autonomous seam welding machine (1000) includes a machine body frame (103). The machine body frame (103) is the outermost part of the machine (1000), which protects the machine (1000) from any external damage. In the machine, the said machine frame (103) is placed on a table (100) for providing support to the said machine (1000). The said welding machine (1000) further includes a mount (104) adapted to hold the said cylindrical workpiece (101). In an exemplary embodiment of the machine, the said mount is a pneumatic holder (104), which is configured inside the said machine frame (103). The said pneumatic holder (104) is adapted to hold the said LPG cylinder (101) (refer to Figs. 2–4). As the name suggests, the said pneumatic holder (104) is operated by pressurized air or gas, preferably pressurized inert gases.
In one embodiment of the present machine, the said pneumatic holder (104) is adapted to rotate the said LPG cylinder (101) for carrying a welding operation in the whole of the cylinder (101). In a machine, the said pneumatic holders (104) are configured inside holes provided on both sides of the machine frame (103) (refer to Fig. 1). In the embodiment of a machine, this configuration of the said holder (104) with the said frame (103) is merely an example and may be configured in a different way also. Further, referring to Fig. 2–7, the said seam welding machine (1000) further includes a box (107) configured inside the machine frame (103). The said box (107) has an opening face towards the cylinder (101). The box (107) is made up of metal, and particularly, the said box is made up of about 3 mm layer of stainless-steel sheet.
Referring to Figs. 5–7, the said autonomous seam welding machine (1000) further includes a light source (102), specifically a LED (102) which is configured to an inner side of the said box (107) (refer to Fig. 6). The said LED (102) is configured in such a manner so as to create a shadow of a circumferential lap joint of the said LPG cylinder (101) by projecting a light on the said LPG cylinder (101). More specifically, the LED (102) projects sharp cut-off light around a welding point to create a dark shadow of the circumferential lap joint of the said LPG cylinder (101). The said autonomous seam welding machine (1000) further includes an RGB camera (108) which is also configured inside the said box (107). The said RGB camera (108) is adapted to capture the images of the shadow of the circumferential lap joint of the said LPG gas cylinder (101) created by the said LED (102) (see Figs. 5–7).
The LED (102) and the RGB camera (108) are configured inside the said box (107) for insulation, thereby protecting the said LED (102) and the said RGB camera (108) from any damage (refer to Fig. 7). The box (107) includes an insulation layer. Preferably, the said box (107) is coated with the said glass wool so that the said box (107) resists the high amount of heat generated during the MIG welding operation. More particularly, the said box (107) is coated with about a 10 mm layer of glass wool. More specifically, the said LED (102) and camera (108) are configured inside the box (107) for protection against a welding flux and heat generated around the said box (107) during the MIG welding operation. In another embodiment of a machine, the box (107) may also protect the LED (102) and the camera (108) from any other damage. Referring to Fig. 4, the said welding machine (1000) further includes a microcontroller (112). The said microcontroller has an operational connection with the said RGB camera (108). The said microcontroller is adapted to process the images of the circumferential lap joint of the said cylinder (101) in an RGB format for tracking the seam path of the gas cylinder (101) accurately.
The microcontroller (112) is adapted to process the RGB images of the circumferential lap joint of the said gas cylinder (101) by passing the said images through different filters for detecting the said seam path of the said cylinder (101) accurately and thereby tracking the seam path of the gas cylinder (101) accordingly. In one embodiment of the present machine, more particularly, the said RGB images of the circumferential lap joint of the cylinder (101) are passed through filters to smooth the noise of the images, thereafter an extracted data is converted into the welding seam path, and thereby realizing the real-time tracking of the seam.
Again, referring to Figs. 5–7, the said autonomous seam welding machine (1000) further includes an ultrasonic sensor (110) which is configured to an extended part of the said box (107). The said ultrasonic sensor (110) is adapted to generate a signal based on a position of a welding torch (106) with respect to the welding point. The received signal is sent to the said microcontroller (112) for processing the said signal to monitor a clearance between the said welding torch (106) and the welding point.
In a machine, the said welding torch (106) is configured to the extended part of the box (107) through a hole (refer to Fig. 4). The said welding torch (106) carries out the MIG welding operation by following the tracked welding seam path of the said gas cylinder (101).
Again, referring to Fig. 4, the said microcontroller (112) is operatively connected to the welding torch (106) for controlling the movement of the said welding torch (106) for performing welding operation in an automated way and accurate manner. More particularly, the said microcontroller (112) has an operational connection with the said welding torch (106) via a stepper motor (109). In the embodiment of the machine, the said stepper motor (109) is configured to the said torch (106). More particularly, the said motor (109) controls the movement of the welding torch (106) by a slider (105) after receiving instructions from the said microcontroller (112). In a machine, the said instructions are based on the tracking of the welding seam path or the position of the welding torch (106) with respect to the said welding point, or the like instructions.
Further coming back to the slider (105), the said slider (105) is mechanically connected to the said welding torch (106) via a sliding mechanism, and the said slider (105) has an operational connection with the said motor (109). The slider (105) slides the said welding torch (106) in upward, downward, right, and left direction according to the welding point of the seam path of the cylinder (101) (refer Figs. 1–9). In one embodiment of the present machine, the machine (1000) has a transparent welding glass (111) which is installed at the machine frame (103). The said welding glass (111) is adapted for a worker to monitor the welding operation.
The working of the autonomous seam welding machine (1000) is explained below.
Firstly, the LED (102), which is isolated inside the box (107), projects the light on the workpiece (101), which is mounted on the pneumatic holder (104) to create the shadow of the circumferential lap joint of the said workpiece. Thereafter, the RGB camera (108), which is also configured inside the box (107), captures the images and transfers the said images to the microcontroller (112). The isolation of said LED (102) and camera (108) inside the box (108) provides insulation. Accordingly, the said microcontroller (112) processes the said images in RGB format for automatically tracking the real-time welding seam path of the said workpiece (101). After that, the microcontroller (112) transfers the signal based on the seam tracking to the said welding torch (106) via the stepper motor for performing the welding operation by following the seam path. At the same time, the ultrasonic sensor (110) generates a signal based on the position of the welding torch with respect to the welding point and transfers the said signal to the microcontroller (112). After that, the microcontroller (112) processes the said signal and repeatedly monitor the clearance between the welding torch (106) and the welding point, and based on that, the welding torch (106) slides in up, down, left, or right direction via the said slider (105) and the said motor (109) for performing welding operation in an automated way.
Table 2
Part number and name of the various components of an autonomous vision sensor-actuator-based circumferential seam path tracker welding machine
Part Number
|
Part Name
|
1000
|
Autonomous seam welding machine
|
100
|
Table
|
101
|
LPG cylinder
|
102
|
Light Source (LED)
|
103
|
Machine Body Frame
|
104
|
Pneumatic Holder
|
105
|
Slider
|
106
|
Welding Torch
|
107
|
Heat Resisting Box
|
108
|
RGB Camera
|
109
|
Stepper Motor
|
110
|
Ultrasonic Sensor
|
111
|
Welding Glass
|
112
|
Microcontroller
|
113
|
Pneumatic cylinder
|