PISFlex: A Pipeline Inspection System with Flexible Mechanism
Unmanned system is one of the technologies that growth recently and highly demands since there are many works that need a large scale of tasks, hazardous avoidance and narrow area that impassable for human. The keywords on this technology are to make the design more flexible in terms of its mechanism as well as long haul accessibility in terms of communication. Therefore, this project has taken initiative to design and develop a small tele-operated pipeline inspection system with flexible mechanism (PISFlex) with graphical user interface (GUI) system through tele-operated system. The total payload of 3kg became the target of this system development and this value has been considered in the total torque required by each motor in its mechanical design. Moreover, the flexibility and adaptability mechanism inspired from Umbrella Mechanism is adapted in its structure design to perform shrinking and expanding behavior. In the control system development, direct current (DC) motor was used as driven devices on each wheel of the system and these motors are controlled from the microcontroller with embedded codes for tele-operational process from GUI system. The proposed prototype was tested on the half-cut flexible pipeline. The experimental result shows that PISFlex able to deal with the changes of pipeline sizes when it is getting curved and confined with the command from user through the GUI system.
The pipelines are very significant tool as they are used in many different industries for various applications such as transportation of gas, water, fuel oils, etc. The project is done specifically done for the Sewer Pipeline Connection System in Malaysia. Over time, they are prone to aging, corrosion, cracks, mechanical damage etc. and these problems leads to the accidents which contributes to the huge losses in terms of both economy, times and lives. This highlights the inevitable need to inspect pipes at a regular interval for the purpose of improved efficiency and convenience for all citizens when using the sewer systems. Hence, conceptualized of inspection robot in pipeline industry is to eliminate the human factor from labor intensive or dangerous, inaccessible work environment and confine space.
Figure 4: PISFLEX GUI for First Prototype
Figure 5: Separated kernel for night vision camera for user
One unit of PISFlex first prototype was designed with PLA+ materials for the frame structure, Arduino UNO as a main processor its controller, encoder for the real-time velocity monitoring through tethered USB cable and a camera with night vision attached at the front of the unit. The overall control system structure can be illustrated as shown in Figure 6.
Table 1: PISFLEX first prototype specification
The method of operation for this robot is prepared with a simple procedure as follows;
Determine the size of the pipeline that need to be maneuvered by the robot. Note: For this prototype the size should not reached 300mm since the minimum contraction of the suspension is 300mm.
Slot the robot into the pipeline by making the front of the robot inside the pipeline at first as shown in Figure 3. This is to ensure the camera is heading during inspection operation.
Switch ON the robot unit and activate the GUI on your PC. Plug-in the USB port between the PC and the robot to tethering the signal between the GUI in PC and the robot unit.
Establish the WiFi camera view in the separate kernel as shown in Figure 5.
Start moving the robot by pushing the Forward button at first as shown in Figure 4.
The robot is ready to be used and the performance of the robot; speed and traveling distance can be measured from the dialing meters in GUI as shown in Figure 4.
Note: For this prototype the robot only prepared to be maneuver not more than 10m.
Figure 1: PISFlex first prototype
Figure 2: State of art for PISFlex design (a) Umbrella details, (b) PISFlex structure design [Pattent Filled Patent Filled: PI 2022000093 MyIPO (2022)
Figure 3: : PISFlex into pipeline slotting procedure
With sparking of new technology in robotic and automation, assisting robot vehicle has big potential to be designed and developed with flexible and adaptability mechanism that required complex mechanical and electronic task. Therefore, a a small tele-operated Pipeline Inspection System with Flexible mechanism (PISFlex) is introduced and designed, as shown in Figure 1, specifically for the limited accessible of sewer pipeline. This project will be highlighting on the development of pipeline inspection system which include the flexibility and adaptability features to ensure the system able to surpassing any angle of pipelines and tunnels. Moreover, PISFlex also considered to compensate with the confined sewer pipeline at range 300mm-400mm large with cornering route and angle maximum 45 degree according to the Sewer Pipeline Specification in Malaysia.
Figure 6: General connection schematic in PISFlex system
PISFlex is designed with flexible both body and wheel suspension as shown in Figure 2. The adaptable wheels’ suspension using Umbrella Mechanism enable PISFlex to freely expand and contracted the wheels in order to ensure the wheel placement on the inner of pipeline wall. Here the free spring-damper piston is applied as suspension. For this prototype the range of this umbrella or Y-shape leg expansion and contraction was designed between 300mm to 400mm in which suitable for the confined pipeline. This idea of flexible mechanism.
On the other hand, the robot also configured with ability to surpassing the cornering point of the pipeline at least with 45-degree angle. The flexible spring is attached on the center of its body as shown in Figure 2(b) to allow this robot to be bended and flexible when facing the cornering pipeline such as elbow and branch joints. The current prototype is operated with at 5-6 VDC at 1.2-1.5A and able to stand up to half and hours of continuous usage.
Figure 7: Example application