This paper presents a planar electromagnetic conveyor for a microfactory. The uniqueness of the conveyor design lies in its arrangement of overlapped 2D mesh coils in matrix configuration that enables to drive a mobile part over long strokes. The conveyor architecture includes a fixed part which consists of 5 $\times$ 5 matrix design that has been fabricated on a multi-layer printed circuit board. An analytical model that takes into account the electromagnetic and friction effects has been developed. A conveyor prototype has been fabricated and experimentally characterized in open loop control. Linear and planar motions, positioning repeatability error, straightness error and rotation have been experimentally measured. From experimental results, the proposed architecture enables long linear displacement strokes ( $\leq$ 70 mm) and rotation ( $\geq$ $\pm$ 12.37°). In addition, a 12 mm/s speed can be achieved for the mobile part at a nominal current of 0.8 A.

A critical component of the highly packaged and automated environment of the micro-factory is its transportation system. It needs to be autonomous, flexible, precise and, crucially, easy to integrate given the compact and dense nature of the micro-factory. We present the modeling and experimental validation of a digital actuator array used as a stick-slip micro conveyance system. This array is based on a modular and scalable design of a 2 x 2 matrix of electromagnetic digital actuators working in open loop collaboration to perform planar conveyance tasks while being easy to integrate. A dynamic model of the array was developed and compared with experimental measurements of the mobile parts kinematics, uni-dimensional and bi-dimensional conveyed object displacements. The experimental measurements were taken with a dual camera set-up: one for the position measurements of the conveyed object and a high-speed camera at 15 kHz for the kinematics of the mobile parts of the actuators and conveyed object. From the experimental tests, we measured a minimum and maximum object displacement step of 7.9 μm and 204.5 μm respectively. The minimum rise time of the digital actuator was 0.8 ms. The bi-dimensional movements of the object demonstrated the planar motion capacity of the array, with generated angles from 1° to 88°. The dynamic model achieved a good correlation with the experimental measurements of the mobile part of the actuator as well as the conveyed object. The open loop control performance of our digital actuation system suggests an interesting alternative to the conveyance systems for the microfactory.

A high-precision planar digital electromagnetic actuator with two displacement directions and four discrete positions is presented in this paper. The four discrete positions are located at each corner of a square cavity where a mobile permanent magnet moves thanks to Lorentz forces generated when a driving current passes through two orthogonal wires placed below the cavity. Four fixed permanent magnets are placed around the cavity in order to ensure high-precision magnetic holding of the mobile magnet at each discrete position. An analytical model of the actuator is presented and used to characterize its properties (switching time, energy consumption, and displaceable mass). Based on this model, an experimental prototype has been developed and then characterized. Comparisons between experimental and simulated results are carried out and show good agreement. The positioning repeatability errors have also been characterized according to the input signal in order to qualify the digital behavior of this high-precision actuator. Finally, an application of this digital actuator as a linear conveyor is presented and experimentally tested.

This paper presents a 3D digital electromagnetic actuator able to reach 12 discrete positions distributed in three-dimensional space. The mobile part of this actuator includes a cuboid permanent magnet fixed in a hexagonal casing. The mobile part is able to reach six discrete positions in xy-plane at level z$_{1}$ and the remaining six discrete positions at level z$_{1}$. The switching of the mobile part in xy-plane is achieved by injecting currents in the fixed planar wires situated beneath it. The actuator design integrates a coil to switch the mobile part between two predefined levels in z-axis. To maintain the mobile part at a discrete position without energy consumption, six fixed cylindrical permanent magnets are placed around the mobile part. To design the actuator, a model has been developed and is presented in this paper. Rapid prototyping approach (laser cutting) is used to fabricate the actuator prototype. The maximum and the minimum strokes in xy-plane are between 0.5 to 1.0 mm while along z-axis the actuator is able to perform a stroke of 1.0 mm. Experiments have been conducted on the prototype to validate the proposed design and the 3D actuation. The performance characterization has been conduced and the experimental and the simulated results have been compared.

Micro-factories are characterized by high modularity, reconfigurability and mobility. To achieve this, the micro-factory needs a conveyor which is able to transport objects in as many degrees of freedom (DoF) as possible, executes optimal trajectories of these objects in terms of energy and precision and is robust to withstand possible malfunctions. In this article, we present the planar conveyance of objects on a digital actuation array following trajectories generated by an adapted A* algorithm. The A* algorithm exploits the predictions of a developed dynamic model of the system to find the optimal paths (in terms of energy) on the conveyor surface. The dynamic model predictions were compared to experimental measurements, obtaining low root-mean-square-errors for all conditions. Uni-dimensional conveyance tests characterized the influence of the control parameters. Then, bi-dimensional motions characterized the conveyor’s performance. From the bi-dimensional test, a position root-mean-square-error of 20 μm was measured for a 1109 μm open-loop controlled trajectory. The modular nature of the array allows easy scaling and avoiding possible malfunctioning zones, increasing the robustness of the micro-conveyor. The experimental tests demonstrate that the proposed device is an interesting alternative for the micro-factory.

In this paper, a novel micro-positioning device based on a 3D digital actuator is presented. The proposed system allows realizing planar motions of micro-objects, which could be implemented in several applications where micro-positioning tasks are needed such as micro-component manufacturing/assembly, biomedicine, scanning microscopy, etc. The device has three degrees of freedom, and it is able to achieve planar motions of a mobile plate in the xy-plane at two different levels along the z-axis. It consists of a hexagonal mobile part composed of a permanent magnet that can reach twelve discrete positions distributed between two z-axis levels (six at each level). Two different approaches are presented to perform positioning tasks of the plate using the digital actuator: the stick-slip and the lift-mode approaches. A comparison between these two approaches is provided on the basis of the plate displacement with respect to different current values and conveyed mass. It was observed that for a current of 2 A, the actuator is able to displace a mass of 1.15 g over a distance of 0.08 mm. The optimal positioning range of the planar device was found to be ±5.40 mm and ±7.05 mm along the x- and y-axis, respectively.