Tridimensional micro-conveyance systems for micro-factory – ALVEO

The work program of the ALVEO project can be divided into three successive phases. The first phase of the project consists in developing a 2D elementary micro-actuator based on a hexagonal architecture with six discrete positions. A multiphysic model (magnetic - electromagnetic - mechanical) of the actuator will be developed and used during the design and sizing phase. A demonstrator of the 2D micro-actuator will then be realized using micro-manufacturing techniques and its performances will be characterized. A model of an array composed of several 2D digital micro-actuators will also be developed during the first phase and will be used to develop and simulate control strategies to define the optimized trajectory of the conveyed object and determine the corresponding movements for the micro-actuators. These control strategies will consider, on the one hand, the possibility to combine elementary actions, each generated by a micro-actuator, in order to carry out complex actions, and on the other hand, the optimal displacement of the object obtained by accumulation of steps. The second phase of the project consists on the development of a hexagonal architecture micro-actuator to which an additional vertical displacement axis will be added. The multiphysic model, developed during the first phase, will be adapted to consider this additional displacement axis. The second phase of the project will result in the realization of a demonstrator of this 3D micro-actuator made by micro-manufacturing process and a performances characterization. The third phase of the project consists of three objectives: the development of an array composed of 3D digital micro-actuators, the development of control strategies coupled with optimization algorithms and the validation of the three-dimensional micro-conveying application.

The work carried out in the ALVEO project has resulted in a micro-conveyance system capable of generating micro-conveyance tasks in the plane on two levels. To achieve this result, models were first developed to simulate the various physical phenomena present in the systems studied (magnetic and electromagnetic forces generated, friction and rebound phenomena, etc.). These models were then used to dimension several prototype micro-conveying systems, which were built using silicon technologies to minimize manufacturing errors. These prototypes implemented architectures of increasing complexity: first square, then hexagonal, initially 2D, then 3D, culminating in a system enabling three-dimensional micro-conveying of objects. The performance of these different prototypes was then characterized, including conveying speed, transportable mass and trajectory error. The work also led to the development of dedicated conveying strategies, by determining the best trajectory to follow for a given displacement, and the microactuator control signals needed to achieve it. These strategies are based on modeling tools and have been implemented and validated experimentally using prototypes developed during the project.

The perspectives for the ALVEO project are based on two major axes. The first one concerns the implementation of the conveyors and control strategies developed in the project on a production system in real conditions considering its specificities. The work carried out was aimed at achieving a flexible system and the application of it to a real micro-conveying application represents a direct application perspective. The second perspective focuses on improving the performance of the micro-conveying system. This improvement can be done according to two main points. The work carried out within the framework of the ALVEO project consists in developing a system capable of carrying out micro-conveying tasks on two different levels. A first perspective would consist in developing a system capable of carrying out conveying tasks on a large number of levels, which will make it possible to really envisage micro-factories organized in the volume and not in the plane. The second perspective consists in developing a modular micro-conveying system composed of elementary modules, each comprising digital micro-actuators, which can be assembled in order to obtain a conveying surface adapted to the desired trajectory.

Duque Tisnes, S.; et al. Trajectory and conveyance validation of a micro conveyor based on a digital electromagnetic actuators array for the micro-factory. Applied Sciences, Micro Robotics Special Issue. 2021, 11(24).

Deshmukh, A.; et al. Planar micro-positioning device based on a 3D digital electromagnetic actuator. Actuators. 2021, 10(12), 310.

Duque Tisnes, S.; et al. Modeling and experimental validation of a planar micro conveyor based on a 2 x 2 array of digital electromagnetic actuators. IEEE/ASME Transactions on Mechatronics. 2021, 26(3), 1422-1432.

Deshmukh, A.; et al. A Novel 3-D Electromagnetic Digital Actuator with 12 Discrete Positions. IEEE/ASME Transactions on Mechatronics. 2018, 23(4), 1653-1661.

The ALVEO project takes place in the Axis 2 “Usine du futur – Système, produit, process” of the Challenge 3 “Stimuler le renouveau industriel” of the 2015 ANR action plan. The proposed study is linked with the micro-factory concept which is well adapted for the manufacturing of miniature objects in small and medium series. A micro-factory is also a highly flexible and reconfigurable device. Numerous studies are actually done on this concept and are generally focused on the development of micro-positioning or micro-gripping devices. Only few studies are however done on the micro-conveyance devices for the micro-factory. The objective of the ALVEO project is to develop systems able to perform three-dimensional conveyance tasks in a micro-factory context. This micro-conveyance system integrates a physical plateform, composed of an electromagnetic micro-actuators array based on a digital principle, and control strategies which ensure an optimal functioning. The digital actuators, which form the physical plateform, dispose of a simple architecture composed of discrete positions between which the mobile part of the actuator can be switched. All intermediate positions correspond only to transient states that cannot be kept in a normal functioning. Therefore, digital actuators require a minimalist control based on energy pulses only needed for a change of state. This characteristic limits then the energy consumption of such actuators, which is a major issue in the light of the 2015 ANR action plan. Digital actuators have also the advantage to maintain the mobile part in discrete position without energy supply. Moreover, because the discrete positions are precisely defined at the manufacturing, no sensor is required for the control, unlike classical systems, that facilitates their integration into compact or highly integrated systems. In the ALVEO project, an original architecture of hexagonal micro-actuator able to perform three-dimensional displacement is proposed which allow reaching a large number of discrete positions (12 positions). Several demonstrators, with increasing complexity level, will be developed during the project that will lead to the development of an array of digital three-dimensional micro-actuators with hexagonal architecture. With such a system, complex actions could be generated by combining simple elementary actions, obtained each one by a micro-actuator. A three-dimensional conveyance application in a micro-factory context will be intended for this demonstrator. Each micro-actuator of the array could be independently controlled ensuring high flexibility and reconfigurability levels which represent two important properties in a micro-factory context. Dedicated control strategies will also be developed during the project taking the specificities and the opportunities offered by the micro-actuators array into accounts. The proposed work in the framework of the ALVEO project will be carried out according to three successive phases. The first phase aims at demonstrating the feasibility of a planar micro-actuator based on a hexagonal architecture with six discrete positions. In the second phase, a micro-actuator based on a three-dimensional architecture with twelve discrete positions will be developed and characterized. During the third phase, the work will be focused on the development of an array composed of three-dimensional twelve discrete positions micro-actuators, on the definition of optimized control strategies and finally, on the validation of the micro-conveyance application in a micro-factory context.