1.2 The Positioning of Activities

As any associate professor my works encompass two main components that are teaching and research activities. My teaching activities are presented in Appendix  A.2. Specifically, the main part of this manuscript is principally devoted to describe my scientific research works. Thus, in the following sections the context in which my works have been carried out are introduced.

1.2.1 Works Background

As stated, my research activities are realized as a member of the Robotic team of the PRISME laboratory. The INSA Centre Val de Loire and University of Orléans are jointly responsible for PRISME laboratory (EPRES 4229). The laboratory also has hosting agreement with the HEI[12] private engineering school located in Châteauroux, Indre, France. PRISME laboratory seeks to carry out multidisciplinary research in the general domain of engineering sciences over a broad range of subject areas, including combustion in engines, energy engineering, aerodynamics, the mechanics of materials, image and signal processing, automatic control and robotics. For this purpose, the laboratory is divided into 2 units: i) Fluids, Mechanics, Materials, Energy (F2ME) and ii) Images, Robotics, Automatic control and Signal (IRAuS). The overall staff of the laboratory is about 150 peoples (90 researchers, around 50 PhD students, and 10 engineers/technicians/administratives staffs). One of the specificity of the PRISME laboratory is that it is spread over 3 departments of the administrative Region Centre Val de Loire, within 7 campuses as illustrated in Figure 1.3.

Figure 1.3: The different PRISME Laboratory locations: Orléans, Bourges, Chartres, Châteauroux and Issoudun. The disk size illustrates the importance of the staff over the different locations.
Figure 1.3: The different PRISME Laboratory locations: Orléans, Bourges, Chartres, Châteauroux and Issoudun. The disk size illustrates the importance of the staff over the different locations.

Within the IRAuS unit, the Robotic team is mainly involved in robotics for biomedical and healthcare applications. Specifically, the Robotic team contributes to the development of methods, tools and techniques for the design and control of innovative robotics systems. To achieve these goals, as of 2018, the team comprised 13 tenured researchers (3 Professors, 1 Associate Professor with HDR[13], 7 Associates Professors, and 2 teachers-researchers who are with HEI). The members of the team are spread over 3 locations: Bourges (10), Châteauroux (2) and Orléans (1), also shown in Figure 1.3.

The Robotic team research topics are divided in 2 main thematic objectives, which are:

  1. interaction and mechatronics design: designing and optimizing innovative mechatronics structures; and developing dedicated control methodologies for robotic platforms;

  2. micro/nano-robotics: dealing with aspects related to the modeling and control of robotic structures at the micro and nanoscale.

Although my activities fall broadly into these two scientific areas, I am more notably involved in the latter theme B. Indeed, most of my research works are devoted to the modeling and control of robotic systems to act/interact at the microworld level. In the same way as the theme A, the overall objectives are to contribute to develop reliable and innovative (micro)robotic systems; but, here, the scientific approach basically differs due to the physical specificity of the microworld. Hence, this manuscript widely focuses on my research activities in the field of micro/nano-robotics that are introduced hereafter.

1.2.2 Positioning of my Research Works

Challenges of the microworld

Since few decades, the societal, industrial and scientific issues related to more and more miniaturize objects or systems are of significant interests. These interests concern various domains such as healthcare, biotechnologies, manufacturing, space, environment, power and so on. This is made possible thanks to the advances in micro/nano-scale sciences and technologies allowing creating tiny tools able to operate in very small spaces (such as within the human body or microfluidic chip); and to control or interact with micro/nano-scale entities efficiently. Such smart small tools, which are referred as microrobots, enable a way to evolve directly in the microworld; that is not conceivable with common macroscale robots or any human skills. These microrobots allow considering many new applications such as innovation for diagnostics or therapies (e.g. from within the human body); microfluidic systems for reliable biotechnological tools; micromanufacturing enhancement; environmental and health monitoring… Furthermore, the considered size together with the advance in the fabrication process and materials design, enable low-cost manufacturing in large numbers. Figure 1.4 illustrates these contexts and the significant elements of the microworld.

Figure 1.4: Representation of the scaling importance towards the microworld. The last row depicts the main vision modalities range.
Figure 1.4: Representation of the scaling importance towards the microworld. The last row depicts the main vision modalities range.

The abilities for the microrobots to manipulate or deal directly with micro/nano-sized objects are very promising, but still remains challenging. Important issues are related to the understanding of the physics of the microworld, the microrobots design and control strategies. Hence, microrobotic is strongly multidisciplinary research fields that include sciences from robotics, microtechnologies, control, mechanical engineering (solid and/or fluid), thermodynamic, electromagnetic, computer engineering, artificial intelligence, and so on. Obviously, all thing experience the same physical forces and are governed by the same laws. However, as many dynamics usually rely on size/length of the entities, their magnitudes and importance change significantly with the scale. The issue is then to study systems whose characteristic dimensions are less than a millimeter, as illustrated in Figure 1.4. The objectives are then to understand and deal with the microworld specific dynamics. Figure 1.5 shows an overview of the challenges, sciences, benefits, and potential applications, adapted from [5].

Secondly, the search for microrobotic systems that must always be smaller, smarter, more versatile with more functionalities… still remains complex to achieve and control. This requires the use of proper models (i.e. that come from different physics), and advanced control strategies (e.g. non-linear, robust, optimal control schemes, etc.). Moreover, such microrobots require efficient power supply, computational capabilities, tools and features allowing manipulating and interact with the microworld.

Figure 1.5: Diagram representative of the challenges, sciences, benefits, and applications of microrobotics.
Figure 1.5: Diagram representative of the challenges, sciences, benefits, and applications of microrobotics.

These various challenges, objectives and problems associated with the lack of knowledge and tools to achieve them are the main motivations of my research works towards the study and the realization of advanced microrobotic tasks. Our original approach, developed later in this manuscript, aims to propose a framework for: from the understanding of the microrobotic system to the definition of their navigation strategies, with a particular attention to biomedical applications.

Microrobotics for biomedical applications

Since the 1980’s with the first surgical guidance robots, the use of robotic systems in medicine and biomedical applications are growing, giving birth to medical robotics fields [6] [7]. The motivations are mainly to reduce trauma, infection risk, postoperative pain, and to improve the quality of healthcare by introducing the latest technological tools from computer science and robotics in biomedical engineering [8]. Resulting in reduced recovery time these advantages have made medical robotics desirable for many types of medical procedures [8]. A significant number of medical robotic system, aimed at augmenting the practitioner capabilities and reducing evasiveness, have been developed up to now [8] [9]. For example, there are the well-known da Vinci® surgical assistance robots by Intuitive Surgical[14] which improves the surgeon technical skills. Historically, such medical robotics topic is the main concern of the Robotic team from the PRISME Laboratory. They have developed solutions such as robotized tele-echography to provide skilled medical care to isolated patients [10] [11].

These various medical solutions have helped to improve the acceptance of the use of robotics systems in clinical practices. In the wake, microrobotic has also emerged as an attractive technology to introduce microscopic helpers to further reduce trauma, to create new diagnoses tools and therapeutic procedures. For example, untethered microscopic devices may navigate within the body for targeted therapies [12]. Another opportunity relies on the design of microfluidic lab-on-a-chip for point-of-care testing diagnostic systems [13]. This interest has been even more enhanced as some biomedical mini-robotic solutions are already commercialized. Aforetime, microrobotic contributes to enhance biomedical operations, such as cells manipulation (e.g. in vitro fertilization), genetic analysis, or intracellular injection of genes, DNA or drugs [14]. Similarly, swallowable endoscopic capsules are also available clinically [15]. Current research aims to explore different technologies to extend these capabilities of such mini-devices to the entire human body [12]. It is in this scientific context that my research works firstly take place.

1.2.3 Scientific Topics

[12] (French for School of High Studies in Engineering) is a private school of engineering.

[13] In France, the HDR award is a general requirement for supervising PhD students and applying for Professeur position..