Mechanically-Intelligent Insect Robot published in Sensors and Actuators

I am happy to announce that my paper showcasing a mechanically controlled SMA inchworm robot, has been in published in Elsevier Sensors and Actuators A: Physical.


Shape Memory Alloy (SMA) based actuators have become ideal candidates for use in compact and lightweight applications. These smart materials have often been referred to as artificial muscles due to their high work volume density. In this paper, a flexure-based SMA powered mechanical oscillator is developed to create an inchworm robot. Here, a novel magnetic latch system is used to create a mechanically-intelligent system that allows the abstraction of any sensors such as temperature probes. This insect robot, weighing only 9.7 g, operates without any control logic or micro-controller and is able to perform a crawling gait untethered. An analytical model of the thermal properties of the SMA coil, for the sizing of the robot speed, and an analytical model of the step length of the insect robot is presented and validated. A working prototype, with a speed of 1.55 mm/s, is showcased in this work.

Graphical Abstract

Publication in Smart Materials and Structures

I am pleased to announce that my paper titled “Designing compliant mechanisms composed of shape memory alloy and actuated by induction heating” has been published in IOPScience Smart Materials and Structures (DOI:

Abstract :

Shape memory alloys (SMAs) are a type of smart materials that reacts mechanically to heat. Due to their complex behavior, they are often used in a simple geometry such as wires. This constrains the output displacement of the alloy to a simple linear contraction of the wire. When a different output displacement is desired, the SMA is coupled to a mechanism that transforms the motion, degrading the compactness of the whole system. To alleviate such issues, we propose fabricating, directly in SMA, a compliant mechanism that performs complex output motions and thus improves integration. The first part of this paper presents a method to design such systems. When coupled with a bias-spring and a heating system, these mechanisms form a full actuator. The conventional heating system relies on Joules losses coming from direct electric conduction through the alloy. However, now that the SMA has a complex shape, passing a current through it becomes an arduous task requiring multiple electrodes making the system cumbersome and deteriorating its integrability. Magnetic induction heating is proposed to tackle this limitation, heating the mechanism without contact and conserving a compact actuator.

I would particularly like to thank my co-author Adrien Thabuis for this excellent work.

Accepted Journal in IEEE IAS

The work titled ‘Characterization and Verification of Eddy-Current Position Sensing for Magnetic Levitation‘ has been accepted to be published on IEEE Transactions on Industry Applications

Abstract :

Magnetically-levitated drives are compelling in applications where the long-lifetime operation or process chamber encapsulation is a requirement. To exploit these advantages, contactless position sensors are needed to estimate the position of the rotor. Off-the-market sensor technologies render high-performance magnetic levitation possible, yet their system integration may be challenging if a drive must be designed to fit existing sensor technology or bulky probes.

In this work, a position-estimation system based on Eddy-current generation is proposed. Two integrated circuits (or only one for less time-critical applications) excite a two-axis differential array of four miniature coils that can resolve positions in the 1 μm range.

Coupled to a microcontroller, this system can sample the position of an electrically conductive target —in this study, the permanent magnet rotor of a magnetically-levitated drive— with frequencies of over 3.5 kHz. This position estimation setup enables the successful levitation of two miniature bearingless disc drives and offers potential towards rotatory speeds in the 20 krpm range.