Miniature Magnetic Climbing Inspection Robots

Industrial plants have an abundance of complex and confined areas that require systematic inspection. Maintenance work is necessary to ensure reliability and safety. In many cases, due to either size limitations or high danger, access is impossible to humans. Current inspections require long and costly dismounting or safety procedures. Robotic inspection could be a convenient solution to overcome the lack of accessibility and safety for human inspectors. In the energy industry for instance, where downtime can cost millions of dollars per day, dedicated and agile robots may pursue inspection faster than humans, thus reducing the duration of overhaul. Additionally, robotic inspection may offer higher repeatability and reliability compared to human inspection. Distraction or simply boredom caused by repetitive tasks may result in an incomplete or failed inspection. Moreover, social costs and the hardness of working in an unfriendly or even toxic environment may be reduced. This work focuses on adhesion analysis, integration and mobility extension of miniature climbing robots for industrial applications. Existing solutions were carefully analysed in order to propose an innovative technology and methodology to be used in the design and implementation of these robots. The main objective was to increase the availability, capability and use of mobile robots for inspection in complex industrial environments. Due to the reduced dimensions of the industrial areas to be inspected, in some cases less than 25 mm, miniaturisation of the robot was required, as well as high mobility in 3D complex environments. Climbing ability is enhanced by improving adhesion techniques and their synergy with locomotion. Ferromagnetic environments are common in industrial facilities. Since magnetic adhesion is superior to other methods, a major effort of this work has been devoted to methodically understand and improve the use of permanent magnets as adhesion and magnetization devices integrated into miniature climbing inspection robots. Implementation of the magnetic adhesion was achieved in different magnetic climbing robots with locomotion principles such as wheels, caterpillars or feet. An innovative obstacle passing mechanism was proposed with the Cy-mag3D robots family. A proposed approach is the use of a Magnetic Switchable Device (MSD) as an adhesive and magnetizing device for inspection robots. Results show that the energy efficiency of MSDs is higher when compared to the vertical mechanical detachment of a system with permanent magnets or an electromagnetic system. MSDs have been used in TUBULO, an inchworm for visual inspection of boiler tubes of 25 mm in diameter, and TREMO, a climbing inchworm for visual inspection of complex ferromagnetic environments. A novel MSD configuration was proved adequate to perform Magnetic Particle Inspection (MPI). This work proposes novel solutions to realise miniature magnetic climbing robots dedicated to inspection. The proven results go beyond the anterior state of the art. Accordingly, inspection robots may move with versatility in industrial environments. The outcome of this work opens new perspectives for the use of mobile climbing robots with direct application in industrial inspection.

Design of a modular robotic system that mimics small fish locomotion and body movements for ethological studies

Frank Bonnet, Bertrand Eric Collignon, Alexey Gribovskiy, Francesco Mondada

Robotic animals are nowadays developed for various types of research, such as bioinspired robotics, biomimetics, and animal behavioral studies. The design of these robots poses great challenges as they often have to achieve very high-level performances in terms of locomotion, size, and visual aspect. We developed a robotic system for direct underwater interactions with small fish species. This robotic platform is composed of two subsystems: a miniature wheeled mobile robot that can achieve complex locomotion patterns and a robotic fish lure that is able to beat its soft caudal peduncle to generate fish-like body movements. The two subsystems are coupled with magnets that allow the robotic lure to reach very high speeds and accelerations, thanks to the mobile robot. We used zebrafish (Danio rerio) to model small fish locomotion patterns and construct a controller for the motion of our robotic system. We have demonstrated that the designed system is able to achieve the same types of motion patterns as the zebrafish while mimicking the body movements of the fish. These results define new standards for robotic fish lures and bring to the field of fish–robot interaction a new tool for ethological studies.

Sciyo2017

Perception, control and planning for (self-)reconfigurable modular robots

Mehmet Hasan Mutlu

Modular robots (MRs) consist of similar modules that can be configured into different shapes. MRs introduce a number of benefits over conventional robots specifically designed for a task. Self-reconfigurable modular robots (SRMRs) are a sub-category of MRs that can perform complex morphological changes by making use of autonomous attachments and detachments. This thesis is pointing out various aspects of MRs with particular interest in SRMRs (but not exclusively). First of all, designs of SRMRs are studied and improvements have been demonstrated in Roombots (RB), a SRMR designed in the Biorobotics Laboratory. The design improvements involve both electromechanical hardware, control and planning aspects. After all improvements, complex scenarios can be studied involving more than 10 modules adding up more than 30 DOF system. Such SRMRs are not intuitive for humans to operate. To overcome this issue, three different user interfaces (UIs) are proposed covering different aspects to simplify use of SRMRs. The first UI is used for conveying shape information to SRMRs using a tangible interaction interface as a proxy. The second one does not have any interaction medium and user directly control SRMRs via gestures that are tracked by external vision systems. The last UI shows possibility of assembling SRMRs in a virtual reality environment using a head mounted display and a hand gesture tracking system. All three of proposed UIs are novel and first of their kind for SRMRs. The final focus is locomotion with modular morphologies and presented in three major studies. Initially, one of the most simplest modular structures, a parallel chain structure, is studied to develop a goal driven neuro-visual locomotion model of a swimming lamprey robot. It is followed by a slightly more complex chain structure. A snake robot is simulated during different serpentine gaits to evaluate implications of different on-board camera placement strategies for such robots. In the last phase, the importance of compliance in legged locomotion is experimentally assessed for quadrupedal modular structures. Compliance of legs as well as a control scheme that acts as a compliant element is taken into consideration for a comparative evaluation. Locomotion is a fundamental part of all mobile robots. Three biologically inspired methods are offered to tackle locomotion of MRs that present performance improvements on multiple aspects as well as better understanding of certain concepts. Although the idea of modularity is widely used in industrial production and common daily items, MRs still don't find much use in daily lives. This thesis brings MRs one step closer to wide daily use by addressing such systems from multiple perspectives.

EPFL2019

Shoaling with fish: using miniature robotic agents to close the interaction loop with groups of zebrafish Danio rerio

Frank Bonnet

Robotic animals are nowadays developed for various types of research, such as bio-inspired robotics, biomimetics and animal behavior studies. The miniaturization of technologies and the increase in performance of embedded systems allowed engineers to develop more powerful, sophisticated and miniature devices. The case of robotic fish is a typical example of such challenging design: the fish locomotion and body movements are difficult to reproduce and the device has to move autonomously underwater. More specifically, in the case of collective animal behavior research, the robotic device has to interact with animals by generating and exploiting signals relevant for social behavior. Once perceived by the animal society as conspecific, these robots can become powerful tools to study the animal behaviors, as they can at the same time monitor the changes in behavior and influence the collective choices of the animal society. In this work, we present novel robotized tools that can integrate shoals of fish in order to study their collective behaviors. This robotic platform is composed of two subsystems: a miniature wheeled mobile robot that can achieve dynamic movements and multi-robot long-duration experiments, and a robotic fish lure that is able to beat its tail to generate fish-like body movements. The two subsystems are coupled with magnets which allows the wheeled mobile robot to steer the robotic fish lure so that it reaches very high speeds and accelerations while achieving shoaling. An experimental setup to conduct studies on mixed societies of artificial and living fish was designed to facilitate the experiments for biologists. A software framework was also implemented to control the robots in a closed-loop using data extracted from visual tracking that retrieved the position of the robots and the fish. We selected the zebrafish Danio rerio as a model to perform experiments to qualify our system. We used the current state of the art on the zebrafish social behavior to define the specifications of the robots, and we performed stimuli analysis to improve their developments. Bio-inspired controllers were designed based on data extracted from experiments with zebrafish for the robots to mimic the zebrafish locomotion underwater. Experiments involving a robot with a shoal of fish in a constrained environment showed that the locomotion of the robot was one of the main factor to affect the collective behavior of zebrafish. We also shown that the body movements and the biomimetic appearance of the lure could increase its acceptance by fish. Finally, an experiment involving a mixed society of fish and robots qualified the robotic system to be integrated among a zebrafish shoal and to be able to influence the collective decisions of the fish. These results are very promising for the field of fish-robot interaction studies, as we showed the effect of the robots in long-duration experiments and repetitively, with the same order of response from the animals.