Frédéric Rochat

Design of Magnetic Switchable Device (MSD) and applications in climbing robot

A Magnetic Switchable Device (MSD) is a ferromagnetic circuit using permanent magnets where the flux can circulate between different paths when its configuration is changed. This routes or cancels the flux through specific surfaces, and thus turns on or off adhesion forces.We present classic and innovative magnetic configuration to realize powerful MSD. We designed and prototyped some miniature systems and give their characteristics. Finally various robotics applications for gripper, anchor and climbing robot are unveiled where the MSD solution has proved to be advantageous.

Cy-mag3D: a simple and miniature climbing robot with advance mobility in ferromagnetic environment

Purpose – The purpose of this paper is to present a novel miniature magnetic climbing robot for industrial inspection. The robot has high mobility with low complexity.Design/methodology/approach – The robot has a miniature cylindrical shape with 28 mm of diameter and 62 mm of width. The robot has two wheels. The adhesion is achieved with an advanced magnetic circuit fixed on the frame of the robot.Findings – From an horizontal sheet, the robot can make transition to almost any intersecting sheet from 10 to 360°. The robot passes inner and outer straight corners in almost any inclination of the gravity.Originality/value – The novel robot opens new possibilities to use mobile robots in ferromagnetic environments with stringent size limitations, as found in power plants. The new mechanism increases mobility and opens a new avenue for inspection robotics. A patent is pending on this system.

Tremo: an inspection climbing inchworm based on magnetic switchable device

TREMO is a compact magnetic climbing inchworm with the capability to move in complex ferromagnetic environments. The robot fits inside a cylinder of 500 mm in height and 120 mm in diameter for an approximate weight of 800 g. It has a modular configuration based on three energy autonomous sub-systems: an arm and two feet. The arm has five degrees of freedom. It has a central articulation with a stroke of 270°. Both ends of the arm have an innovative articulation based on a differential system. This allows unlimited rotation of 360° in the heading angles and 180° in the elevation angle. At both ends of the arm a camera is mounted. The feet are donut-shaped and are mounted around the camera. The climbing ability is based on the advantageous properties of Magnetic Switchable Devices (MSD) [1]. Each feet of the robot embeds three MSD for better compliance and stability of the adhesion to the surface. The three MSD of one feet together with their motors weight 32 g and can hold above 90 N.

TRIPILLAR: Miniature magnetic caterpillar climbing robot with plane transition ability

In this paper, we describe a miniature climbing robot, 96 x 46 x 64 [mm3], able to climb ferromagnetic surfaces and to make inner plane to plane transition using only two degrees of freedom. Our robot, named TRIPILLAR, combines magnetic caterpillars and magnets to climb planar ferromagnetic surfaces. Two triangular tracks are mounted in a differential drive mode, which allows squid steering and on spot turning. Exploiting the particular geometry and magnetic properties of this arrangement, TRIPILLAR is able to transit between intersecting surfaces. The intersection angle ranges from -10° to 90° on the pitch angle of the coordinate system of the robot regardless of the orientation of gravity. A possible path is to move from ground to ceiling and back. This achievement opens new avenues for mobile robotics inspection of ferromagnetic industrial structure with stringent size restriction, like the one encountered in power plants.

Climbing robot with thermal glue

Climbing robots require an adhesion principle in order to overcome gravity. Many physical principles have been used. In this work, the use of thermal glue is proposed. The implementation of miniature thermal glue dispenser is presented with experimental results. The adhesion force depends on the surface, but 7 N/cm^2 is achieved on aluminium and synthetic surfaces. Several ideas were tested to save energy for detaching the glue foot. A climbing robot using this innovative adhesion principle was built. The strength and disadvantage of this technique are presented. The system offers an alternative solution to other commonly used method.

Cy-mag3De: magnetic climbing inspection robot

Cy-Mag3De is a magnetic climbing inspection robot with advanced mobility. It is based on an innovative, award-winning and patented magnetic design. Its mobility is further enhanced thanks to a novel active tail. The robot has a cylindrical shape of 80 mm in diameter and 233 mm in length and a weight of 1.6 kg. It is energy autonomous with distributed batteries, has a camera and sends wireless video feed-back to the remote user interface. The robot is very integrated, robust and allows excellent mobility and visual inspection in complex ferromagnetic environment. It opens new avenue for climbing magnetic inspection robots.

Magnetic wheels optimization and application to the MagneBike climbing robot

Magnetic wheels are a powerful solution to design inspection climbing robots with excellent mobility. Magnetic wheels optimization based on simulations and the results that were obtained on prototypes are presented. The measured adhesion was doubled between the classic configuration and a novel multilayer one sharing exactly the same four magnets and the same total volume of iron. This know-how is then applied to optimize magnetic wheels for the existing robot called MagneBike. The adhesion force has been multiplied by 2 to 3 times depending on the conditions. Those amazing improvements open new possibilities for miniaturization of climbing robots or payloads increase.

Tubulo II: magnetic climbing inchworm for inspection of boiler tubes

TUBULO II is a climbing inspection robot with for inner inspection of boiler tubes. Its locomotion principle is the inchworm type. The adhesion is realized with Magnetic Switchable Device [1]. The inner is able to operate within a tube of inner bore diameter of 25 mm or 1 inch. The robot is modular. The robot and locomotion principle are robust and withstand the harsh environment of corroded boiler tubes. The construction is resistant to water and ferromagnetic particles that separate from the wall. The robot achieves a mean speed of 18 cm/min.