Affordable flexible hybrid manipulator for miniaturised product assembly

Miniaturised assembly systems are capable of assembling parts of a few millimetres in size with an accuracy of a few micrometres. Reducing the size and the cost of such a system while increasing its flexibility and accuracy is a challenging issue. The introduction of hybrid manipulation, also called coarse/fine manipulation, within an assembly system is the solution investigated in this thesis. A micro-motion stage (MMS) is designed to be used as the fine positioning mechanism of the hybrid assembly system. MMSs often integrate compliant micro-motion stages (CMMSs) to achieve higher performances than the conventional MMSs. CMMSs are mechanisms that transmit an output force and displacement through the deformation of their structure. Although widely studied, the design and modelling techniques of these mechanisms still need to be improved and simplified. Firstly, the linear modelling of CMMSs is evaluated and two polymer prototypes are fabricated and characterised. It is found that polymer based designs have a low fabrication cost but not suitable for construction of a micro-assembly system. A simplified nonlinear model is then derived and integrated within an analytical model, allowing for the full characterisation of the CMMS in terms of stiffness and range of motion. An aluminium CMMS is fabricated based on the optimisation results from the analytical model and is integrated within an MMS. The MMS is controlled using dual-range positioning to achieve a low-cost positioning accuracy better than 2µm within a workspace of 4.4×4.4mm2. Finally, a hybrid manipulator is designed to assemble mobile-phone cameras and sensors automatically. A conventional robot manipulator is used to pick and place the parts in coarse mode while the aluminium CMMS based MMS is used for fine alignment of the parts. A high-resolution vision system is used to locate the parts on the substrate and to measure the relative position of the manipulator above MMS using a calibration grid with square patterns. The overall placement accuracy of the assembly system is ±24µm at 3σ and can reach 2µm, for a total cost of less than £50k, thus demonstrating the suitability of hybrid manipulation for desktop-size miniaturised assembly systems. The precision of the existing system could be significantly improved by making the manipulator stiffer (i.e. preloaded bearings…) and adjustable to compensate for misalignment. Further improvement could also be made on the calibration of the vision system. The system could be either scaled up or down using the same architecture while adapting the controllers to the scale.Engineering and Physical Sciences Research Council (EPSRC

Design, Fabrication and Testing of a Dual-Range XY Micro-Motion Stage Driven by Voice Coil Actuators

Nowadays, compliant micro-motion stages offer high positioning accuracy and repeatability. When assembled with conventional stages, the resulting dual-range positioning systems allow for nanometer scale accuracy within a centimeter scale working area. However, such systems invoke a high cost and large footprint. This paper presents a low-cost, compact compliant XY micro-motion stage where dual-range manipulation has been implemented in an effort to maintain the workspace area and increase the positioning accuracy. The method presented in this work employs the use of a large range/low resolution linear encoder to measure the position of the stage (coarse positioning), before using short range/high resolution capacitive sensors to correct the positioning error (fine positioning). This solution achieves a positioning accuracy close to 1μm within a workspace of ±2.2mm 2.2mm. The compliant stage has been machined from Aluminum 7075-T6 using Wire Electric Discharge Machining (WEDM). This material is well known for its large reversible strain and its suitability for compliant mechanisms

Design, Fabrication and Testing of a Dual-Range XY Micro-Motion Stage Driven by Voice Coil Actuators

Nowadays, compliant micro-motion stages offer high positioning accuracy and repeatability. When assembled with conventional stages, the resulting dual-range positioning systems allow for nanometer scale accuracy within a centimeter scale working area. However, such systems invoke a high cost and large footprint. This paper presents a low-cost, compact compliant XY micro-motion stage where dual-range manipulation has been implemented in an effort to maintain the workspace area and increase the positioning accuracy. The method presented in this work employs the use of a large range/low resolution linear encoder to measure the position of the stage (coarse positioning), before using short range/high resolution capacitive sensors to correct the positioning error (fine positioning). This solution achieves a positioning accuracy close to 1μm within a workspace of ±2.2mm 2.2mm. The compliant stage has been machined from Aluminum 7075-T6 using Wire Electric Discharge Machining (WEDM). This material is well known for its large reversible strain and its suitability for compliant mechanisms

Research data supporting for "On a Simplified Nonlinear Analytical Model for the Characterisation and Design Optimisation of a Compliant XY Micro-Motion Stage"

Source data associated with Figures 10, 15 and 16 in the pape

SYSTEME DE CONTROLE DE CHARGE POUR BATTERIE DE TRACTION DE VEHICULE AUTOMOBILE, VEHICULE ET PROCEDE SUR LA BASE D’UN TEL SYSTEME

L’invention concerne un système de contrôle de charge configuré notamment pour une batterie de traction de véhicule automobile, comprenant : Le système contrôle un courant (I) quelle que soit la tension (V), pendant une charge, jusqu'à ce que la tension (V) atteigne une valeur de tension maximale (Vmax). En outre, le système contrôle une tension de décharge quel que soit le courant (I), pendant la décharge jusqu'à ce que le courant (I) atteigne une valeur de courant minimale (Imin) ; Selon l’invention, le système de contrôle met en œuvre des impulsions de courant triangulaires (R) et/ou trapézoïdales à un ou plusieurs niveaux d’amplitude (Ipk_c), chaque impulsion (R) comprenant un gradient positif constant ou par paliers et un gradient constant négatif ou par paliers. L’invention concerne également un véhicule et un procédé sur la base d’un tel système