Experimental Investigation of the Vibro-impact Capsule System

Dr. Yang Liu would like to acknowledge the financial support for the Small Research Grant (31841) by the Carnegie Trust for the Universities of Scotland. This work is also partially supported by the National Natural Science Foundation of China (Grant Nos. 11672257 and 11402224), the Natural Science Foundation of Jiangsu Province of China (Grant No. BK20161314).Peer reviewedPublisher PD

Magnetic bearings for vibration control

A survey is presented on the research of the Institute of Mechanics of the ETH in the field of vibration control with magnetic bearings. It shows a method for modelling an elastic rotor so that it can be represented by a low order model amenable to control techniques. It deals with the control law and spill-over effects, and it also discusses experimental results for an active resonance damper

Original hybrid control for robotic structures using magnetic shape memory alloys actuators.

International audienceMagnetic Shape Memory Alloys (MSMA) are relatively new active materials but at this time they are not actually very used as actuators despite a high strain and a small response time. This is probably due in part to a large hysteresis and a strong non-linear behaviour. In this paper, an original hybrid control is designed taking into account dynamical effects and hysteretic behaviour in order to increase static gain of the system. After a short presentation of MSMA behaviour, a modelling is proposed to obtain two different control strategies. Some experimental results are also given

Modeling and control of micro-mechatronic devices : application of variational and energetic methods for micro-actuator design.

International audienceThis paper is focused on a modeling procedure wellsuited for the design of micro-mechatronic systems and especially for micro-actuators. The purpose of this publication is to show that the variational and energetical methods is not only wellsuited to model classical micro-mechatronic devices but that they are also well-suited to include complex dynamical behaviour such as non-linearity and hysteretical behaviour. This procedure is applied to the design of a new actuator using one of the relatively new smart materials, the Magnetic Shape Memory Alloys (MSMAs). It should be stressed that the presented approach can be extented to a great range of other smart materials and that the description can be easily extented up to the control level

Modelling of a MEMS-based microgripper : application to dexterous micromanipulation.

International audienceMEMS-based microgrippers with integrated force sensor have proved their efficiency to perform dexterous micromanipulation tasks through gripping forces sensing and control. For force control, knowledge based models are more relevant and gives better physical significance than the use of black box models. However this approach is often limited by many problems commonly encountered in the MEMS (micro electromechanical systems) structures such as: complex architectures, nonlinear behaviors and parameters uncertainties due to fabrication process at the micrometer scale. For these reasons theoretical approaches must be compared with experiments. This paper describes a modelling approach of a MEMS-based microgripper with integrated force sensor while handling micro-glass balls of 80μm diameter. Therefore, a state space representation is developed to couple both the dynamics of the actuation and sensing subsystems of the gripper through the stiffness of the manipulated object. A knowledge based model is obtained for small displacements at the tip of the gripper arms (small gripping forces) and is compared with experimental approaches. Good agreements are observed allowing interesting perspectives for the control

From canonical Hamiltonian to Port-Hamiltonian modeling application to magnetic shape memory alloys actuators.

International audienceThis paper presents the modelling of an actuator based on Magnetic Shape Memory Alloys (MSMA). The actuation principle relies on the ability of the material to change its shape under the application of a magnetic field. Previous models proposed by authors were based on canonical (symplectic) Hamiltonian modeling and thermodynamics of irreversible processes. These models, though physically cogent, are non-minimal differential algebraic dynamical models and hence less adapted for control purposes.This paper therefore proposes a modified and systemoriented modeling procedure which lends itself naturally to a port-Hamiltonian model. The latter is found to be a minimal realization of the above whereby interconnection between subsystems is clearly visible. Using Lagrange multipliers, constraints which arise due to causality and interconnection are expressed. In the last section, Differential Algebraic Equations (DAE) resulting from previous models are reduced to Ordinary Differential Equations (ODE) and by using coordinate transformations, constraints are decoupled from the system input/output. The resulting model is well-suited for control

Discovering Sparse Hysteresis Models: A Data-driven Study for Piezoelectric Materials and Perspectives on Magnetic Hysteresis

This article presents an approach for modelling hysteresis in piezoelectric materials that leverages recent advancements in machine learning, particularly in sparse-regression techniques. While sparse regression has previously been used to model various scientific and engineering phenomena, its application to nonlinear hysteresis modelling in piezoelectric materials has yet to be explored. The study employs the least-squares algorithm with sequential threshold to model the dynamic system responsible for hysteresis, resulting in a concise model that accurately predicts hysteresis for both simulated and experimental piezoelectric material data. Additionally, insights are provided on sparse white-box modelling of hysteresis for magnetic materials taking non-oriented electrical steel as an example. The presented approach is compared to traditional regression-based and neural network methods, demonstrating its efficiency and robustness

Nonlinear Hamiltonian modelling of magnetic shape memory alloy based actuators.

International audienceThis paper proposes an application of the Lagrangian formalism and its Hamiltonian extension to design, model and control a mechatronic system using Magnetic Shape Memory Alloys. In this aim, an original dynamical modelling of a Magnetic Shape Memory Alloy based actuator is presented. Energy-based techniques are used to obtain a coherent modelling of the magnetical, mechanical and thermodynamic phenomena. The Lagrangian formalism, well suited in such a case, is introduced and used to take into account the dynamical effects. Hamilton equations are deduced and used for the computation of the theoretical behaviour of this actuator. These numerical simulations are compared with some experimental measurements permitting the validation of the proposed modelling. Beyond the work presented here, these results will be used to design an energy shaping nonlinear control well-adapted for a strongly nonlinear active material

Drag-free and attitude control for the GOCE satellite

The paper concerns Drag-Free and Attitude Control of the European satellite Gravity field and steady-state Ocean Circulation Explorer (GOCE) during the science phase. Design has followed Embedded Model Control, where a spacecraft/environment discrete-time model becomes the realtime control core and is interfaced to actuators and sensors via tuneable feedback laws. Drag-free control implies cancelling non-gravitational forces and all torques, leaving the satellite to free fall subject only to gravity. In addition, for reasons of science, the spacecraft must be carefully aligned to the local orbital frame, retrieved from range and rate of a Global Positioning System receiver. Accurate drag-free and attitude control requires proportional and low-noise thrusting, which in turn raises the problem of propellant saving. Six-axis drag-free control is driven by accurate acceleration measurements provided by the mission payload. Their angular components must be combined with the star-tracker attitude so as to compensate accelerometer drift. Simulated results are presented and discusse