Drive Modules for Low Diameter Pipe Inspection Multi-configurable Micro-robots* A. Brunete, M. Hernando, E.Gambao Dpto. Ing. Sistemas y Automtica (DISAM), E.T.S.I.I. Universidad Politcnica de Madrid (U.P.M.) Jos Gutierrez Abascal 2, 28006 Madrid, Spain abrunete, hernando, gambaoetsii.upm.es http:/www.disam.upm.es/microtub/ * This work is supported by the Spanish “Ministerio de Ciencia y Tecnologa” (project TAMAI TIC2001 3838 C03 03). . Abstract In this poster, two drive modules and some other auxiliary modules for multi-configurable pipe inspection micro-robots are presented. The inspection of low diameter pipes is a subject of great complexity due to the small operation environment in which the tasks must be developed. Besides, the construction of microrobots for specific pipe inspection is too expensive. The possibility to have a micro-robot that combines different locomotion gaits allows overcoming these disadvantages. Thus, by changing configuration the micro- robot could be able to perform different tasks in different environments. I. INTRODUCTION The purpose of the MICROTUB project is the design and construction of a micro-robot able to move in pipes and tubes (straight or not) of about 26mm diameter. The development of this micro-robot will guide to the automation of inspection and maintenance of pipes and tubes at a lower cost in for example sewer systems, gas pipelines, water, gas and heating pipes in buildingsetc. Although there are many robots for pipe inspection, generally they are conceived for pipes of industrial applications, which have a bigger diameter, like gas pipelines or hydroelectric power stations. In this poster we show two drive modules and other auxiliary modules for micro-robots dedicated to pipe exploration for detection of breakages, holes, leaks and any kind of defects in pipes of about 26mm diameter. These modules are conceived to be part of a multi- configurable micro-robot. Reconfigurability is a very important characteristic because it allows the micro-robot to have its modules rearranged and to perform a great variety of tasks. The goal of this project is to develop a robotic chain heterogeneous manually reconfigurable system, according to the classification in 34. Some of the advantages of modular systems are versatility, simplicity, robustness and low cost 12. During the design every module has been minimized as much as possible, achieving a final diameter for each module of less than 26mm. This miniaturization adds a great complexity to the design of the modules, due to the limitation in components, electronics and fabrication techniques. Two fabrication techniques used in these prototypes are stereolithography and micromachining. The modules presented are: two drive modules (“helicoidal” and “worm-like” drive module -including support and extension modules) and three auxiliary modules (“rotation”, “support” and “camera” module). The two types of drive modules allow adapting to different canalizations. The robot is designed to do visual inspection of pipes, but future versions will include sensors for detection and positioning. II. MODULES A. Helicoidal drive module This module (fig.1) was designed to be a fast drive module. It is composed of two parts: the body and the rotating head. The wheels in the rotating head are distributed along the crown making a 15 angle with the vertical. When the head turns, it goes forward in a helicoidal movement that pulls the body of the microrobot. The wheels of the body help to keep the module centred in the pipe. The head is linked to a 3 phase brushless Maxon micro motor through a gearhead, which has been designed in order to get the appropriate reduction (1/24) and speed. The wheels, its axis and the support system have been manufactured by micromachining, and the other parts (except for the gears) have been made using stereolithography. The fact that the head of the robot rotates around the robot axis involves the necessity to design a channel for electrical wires that goes through the entire robot to interconnect the front and the rear part of the robot. The control of the motor was performed in a first step by a Maxon motor control board AECS 35/3. This board supplies the 3 phase signals that the motor demands. Fig. 1. Picture of the drive module One of the main problems that this board has is the power consumption. It operates at a range of 8 to 30 V, and requires up to 5A. This is a huge power demand, so in next versions a special control board is being designed. Also, some similar models but with miniaturized conventional motors are being researched. This module was tested in a 30 cm straight pipe with different slopes angles. The microrobot was able to go forward even when the pipe was set to vertical position. The helicoidal approach shows itself as a very interesting mean of locomotion for microrobots. The results