Dominique Gendreau

3D-Printing: A promising technology to design three-dimensional microsystems

System miniaturization remains an important challenge in the field of microrobotics. Several works have been raised in this context. Maybe the most known and widespread are MEMS devices based on clean room technologies. Although they give option to design small systems with mico/nano features, such technologies are limited to planar structures with two or three degrees of freedom (DOF). To tackle this limitation, a new approach is proposed in this paper. Instead of planar construction, we proposed here to design three-dimensional micro-systems by taking advantages of additive manufacturing technology, namely 3D printing. The final objective consists to design a monolithic structure in one operation without assembly. Then functionalization could be achieved by equipping the structure with actuators and sensors. Starting from the fact that any complex structure could be decomposed into basic elements such as articulations or flexures, this paper will focus on how articulations could be fabricated without assembly using 3D printing facilities. Combining those articulations which are considered as fundamental bricks will make possible to design complex monolithic structures. As an illustration, a pivot articulation is experimentally demonstrated using 3D printing.

Design, static modeling and simulation of a 5-DOF precise piezoelectric positioner

This paper presents the design, the static modeling and the performances simulation of a five degrees of freedom precise positioner. Based on piezoelectric stack actuators, the positioner is able to perform high resolution x-y-z linear motions and angular motions about x and about y axes. After presenting the design, the static modeling is carried out in order to understand the functioning of the positioner. The simulation of the model is afterwards carried out to estimate the ranges of motions that it can perform. The positioner is very promising in various applications that require dexterity and high resolution displacement such as in images scanning with atomic force microscopes, in micromanipulation or microassembly, etc.

Additive manufacturing: Design of a basic pivot articulation actuated with SMA wire

Today, the rapid advance of additive manufacturing, namely 3D printing, gives options and capabilities to simplify the fabrication of three-dimensional complex structures. In fact, such technology brings a real rupture comparing to conventional technologies in terms of design and manufacturing. Taking those advantages, this paper presents the design and the fabrication of a monolithic pivot articulation. First, the skeleton of the articulation is designed as a monolithic bloc. Then, the articulation is fabricated in one operation without assembly. To functionalize the articulation a Shape Alloy Memory (SMA) wire is utilized. Its advantage is the ease of integration thanks to the low diameter of the wire and the expected grooves within the printed structure, making possible the realization of miniaturized complex structures and the introduction of the actuation even inside this latter. The whole actuated structure has a centimeter size and serves as a proof of concept. Experiments are carried out to demonstrate the interest of the realized prototype and thus to highlight that 3D printing could be potential in the development of complex actuated structures.

Design, modeling and simulation of a three-layer piezoelectric cantilevered actuator with collocated sensor

A new piezoelectric actuator with collocated sensor is designed, modeled and simulated. The structure has three piezoelectric layers where the two external layers serve for the actuation by a convenient application of electrical potentials, and the middle layer serves as the sensor. After presenting the principle of the structure, a model is developed for the actuator and as well as for the sensor. Then simulation is carried out to evaluate their performances. The novel structure is very promising for applications that require control and automation, especially in situations where the use of sensors is unfeasible or difficult.