Investigation of the behaviour of a new miniature carbon-paraffin phase-change actuator

Conference of 4th IFToMM International Symposium on Robotics and Mechatronics, ISRM 2015 ; Conference Date: 23 June 2015 Through 25 June 2015; Conference Code:177279International audienceThis paper presents a new millimeter-sized membrane actuator utilizing the volume expansion, resulting from a phase-change composite material, induced by self-heating through the Joule effect. The composite consists of carbon particles as the conductive elements and of paraffin wax as the polymer matrix. The behavior of the actuator is experimentally characterised by measuring its external temperature, its electrical resistance and the membrane deflection. Several factors influencing these measurements are identified and briefly discussed. A detailed analysis of the experimental findings follows, so as to provide a deeper physical understanding of the observed actuator behavior, thus allowing future design and performance improvements

A new optimal design method for electrostatically actuated silicon-based MEMS: Application to a micro-gripper with large stroke and high force resolution

Conference of 1st International Conference on Engineering and Applied Sciences Optimization, OPT-i 2014 ; Conference Date: 4 June 2014 Through 6 June 2014; Conference Code:108723International audienceThe design of Micro Electro Mechanical Systems (MEMS) is often based on the use of costly trial and error method which depends highly on the technical skills of the involved engineers. The drawback of such a procedure is to lead to sub-optimal designs and poor performance at the end. Some research works on dedicated optimization tools have begun a few years ago. The present paper deals with the development of a dedicated optimal design tool for monolithic MEMS, fabricated using the Silicon On Insulator (SOI) process. This tool is an evolution of a previously developed heuristic method, using a multi-objective evolutionary algorithm and a compliant building blocks library. It has been adapted and implemented in the MEMS design software called FlexIn SOI (Flexible Innovation for SOI), which account for the anisotropic elastic behavior of the Single Cristal Silicon material for the Finite Element evaluation of the fitness functions involved in the optimization process. To illustrate the usefulness of this tool, the automatic optimal design of a monolithic microgripper has been investigated. Here, the micro-fabrication process resolution is defined as an optimization constraint. Five dedicated objective functions have been considered to quantify real performances of the gripper, and also to be able to consider the use recommendations of associated inter-digital actuators and sensors. At the end of the optimization process, the nonlinear comb-drive actuator stiffness has been considered to select an electromechanically stable solution among Pareto front. This solution has been prototyped and characterized. It showed very outstanding performances regarding state-of-the-art micro-grippers [1], thus validating the proposed optimal design method

'MISS Heart': Assisting Systems for Minimal Invasive Smart Suturing in Cardiac Surgery - A Conceptually Closed-Loop Approach

The project MISS (Minimal invasive smart suture) provides solutions and concepts for several key issues within cardiac surgery. These issues include pre-operative imagebased stenosis detection and planning, intra-operative semiautomatic registration and dynamically adapting of video and angiography data, as well as the presentation of two novel concepts for bypass connection. The proposed solutions are conceptually parts of a closed-loop surgical interaction process and will in the mid-term be connected accordingly