Development of modularized airtight controller for mobile welding robot working in harsh environments

• Initial deployment of a modularized airtight controller with an active heat dissipating method.
• Difficulties of exact identifications of the entire heat transfer coefficient in real field.
• Practical evaluation of the heat dissipating capacity of manufactured heat dissipating system.
• It will greatly help in solving the heat dissipation problem of various field mobile robots.

This paper proposes the design and validation of a new hermetic controller for mobile robots working in a hazardous environment. Two years ago, we obtained very successful results with regard to the development of the new mobile robot RRX, which can weld, blast, and paint double-hulled structures during the shipbuilding process. At that time, some attempts were made to design a modular and hermetic controller to secure a robust cooling performance and dustproof quality because the temperature is 40–50 °C during the summer, and such operations produce considerable amounts of metallic dust such as fumes. This naturally represents a very hazardous environment for the robot's controller, for which the temperature should be maintained at its rated level, and the body should be kept fully airtight to prevent the inflow of metallic dust. Thus, in that research, heat pipes were successfully adopted to satisfy these design constraints by dissipating the heat from the servomotor drivers and several power units without any airflow into the controller for cooling. The proposed cooling system is composed of heat pipes, cooling fins, fans, and L-shaped brackets for transferring the produced heat from the heating resources to the heat pipes. Experiments were performed in the field to obtain information on the motor driver's heating value and work site temperatures as boundary conditions of the heat transfer problem, and a modular and hermetic controller for mobile robots working in hazardous environments was successfully developed and validated. The obtained experimental results fully support the idea that this design is appropriate for the controller to maintain a stable performance in a harsh environment.