This topical review discusses recent development and trends on scanning micromirrors for biomedical applications. This also includes a biomedical micro robot for precise manipulations in a limited volume. The characteristics of medical scanning micromirror are explained in general with the fundamental of microelectromechanical systems (MEMS) for fabrication processes. Along with the explanations of mechanism and design, the principle of actuation are provided for general readers. In this review, several testing methodology and examples are described based on many types of actuators, such as, electrothermal actuators, electrostatic actuators, electromagnetic actuators, pneumatic actuators, and shape memory alloy. Moreover, this review provides description of the key fabrication processes and common materials in order to be a basic guideline for selecting micro-actuators. With recent developments on scanning micromirrors, performances of biomedical application are enhanced for higher resolution, high accuracy, and high dexterity. With further developments on integrations and control schemes, MEMS-based scanning micromirrors would be able to achieve a better performance for medical applications due to small size, ease in microfabrication, mass production, high scanning speed, low power consumption, mechanical stable, and integration compatibility.

This paper deals with a historical overview of the activities of the French FEMTO-ST institute in the field of microrobotic manipulation and assembly. It firstly shows tools developed for fine and coarse positioning: 4 DOF microgrippers, 2 DOF modules and smart surfaces. The paper then goes on the automation of tridimensional microassembly of objects measuring between 10 and 400 microns. We are especially focusing on several principles. Closed loop control based on micro-vision has been studied and applied on the fully automatic assembly of several 400 microns objects. Force control has been also analyzed and is proposed for optical Microsystems assembly. At least, open loop trajectories of 40 microns objects with a throughput of 1,800 unit per hour have been achieved. Scientific and technological aspects and industrial relevance will be presented. Keywords Microgrippers • Microassembly • Micromanipulation • Microrobotic automation • MEMS assembly 1 Introduction Until now, miniaturization was driven by a general diminution of the volume of the product (e.g. cell phones). Currently, the major objective of the miniaturization is to

The 3D integration of hybrid chips is a viable approach for the micro-optical technologies to reduce the costs of assembly and packaging. In this paper a technology platform for the hybrid integration of MOEMS components on a reconfigurable free-space silicon micro-optical bench is presented. In this approach a desired optical component (e.g. micromirror, microlens) is integrated with removable and adjustable silicon holder which can be manipulated, aligned and fixed in the precisely etched rail of the silicon baseplate by use of robotic micro-assembly station. An active-based gripping system allows modification of the holder position on the baseplate with nanometre precision. The fabrication processes of the micromachined parts of the micro-optical bench, based on bulk micromachining of standard silicon wafer and SOI wafer, are described. The successful assembly of the holders, equipped with micromirror and refractive glass ball microlens, on the baseplate rail is demonstrated.

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During micro-assembly processes, surface forces influence the behavior of micro-objects more than volumic forces.Generally contacts happen between a microgripper and a micro-objet or a substrate and a micro-object. The pull-off force which represents the force required to break a contact is one of the predominant problem in micro-assembly. Now, current force measurements are mostly focused on sphere-plane geometries and models are based on nanoscale theories. The aim of this article is to propose a measurement setup able to evaluate the pull-off force for a planar contact (most frequent kind of contact in micro-assembly). Experimental force measurements based on a capacitive microforce sensor and micro/nano robotic system are carried out. The proposed device enables the study of pull-off forces according to the preload force and the contact angle. Finally experimental results are discussed and compared with a model.

This review demonstrates that 4D printing constitutes a key technology to enable significant advances in microrobotics. Unlike traditional microfabrication techniques, 4D printing provides higher versatility, more sophisticated designs, and a wide range of sensing and actuation possibilities, opening wide new avenues for the next generation of microrobots. It brings disruptive solutions in terms of variety of stimuli, workspaces, motion complexities, response time, function execution, and genuinely 3D microrobots. This review brings to light how soft and smart materials directly printed in 3D are particularly well suited for microrobotics requirements. This review gives an overview of 4D printing in microrobotics, highlighting advanced microrobotics requirements, fabrication methods, used smart materials, activation techniques, recent advances in the microrobotics field, and emerging opportunities.

Shape memory alloys (SMAs) are a group of metallic alloys capable of sustaining large inelastic strains that can be recovered when subjected to a specific process between two distinct phases. Regarding their unique and outstanding properties, SMAs have drawn considerable attention in various domains and recently became appropriate candidates for origami robots, that require bi-directional rotational motion actuation with limited operational space. However, longitudinal motion-driven actuators are frequently investigated and commonly mentioned, whereas studies in SMA-based rotational motion actuation is still very limited in the literature. This work provides a review of different research efforts related to SMA-based actuators for bi-directional rotational motion (BRM), thus provides a survey and classification of current approaches and design tools that can be applied to origami robots in order to achieve shape-changing. For this purpose, analytical tools for description of actuator behaviour are presented, followed by characterisation and performance prediction. Afterward, the actuators’ design methods, sensing, and controlling strategies are discussed. Finally, open challenges are discussed.