Towards a compact XYZ positioning system with built-in actuators using 3D printing of conductive polymer

Technological advances in additive manufacturing have made it possible to exploit composite materials, such as carbon-doped filaments, synthesised for specific function with tailored properties. The integration of carbon fibres, with good electrical and thermal conductivity, within an insulating polylactic acid (PLA) matrix produces a conductive functional material. These properties allow to manufacture mesoscopic electrothermal actuators and more complex monolithic structures including them. A compact and monolithic 3D printable positioning system with built-in V-shaped actuators is proposed in this paper. The prototype presented has an 86.2mm ^3 workspace for a particularly compact footprint, i.e. 206mm × 109mm × 21mm. In this system, the linear motions along the X and Y axes are decoupled from the linear motion along Z, which is also decoupled from the rotation around Z, thus simplifying future kinematic control strategies. Multi-physics coupling analyses are performed in ANSYS to validate the estimated performance of each component of the positioning system. Then, experimental characterisations based on 3D printed prototypes were carried out and showed good agreement between models and experiments. These first results also include the implementation of a first closed loop control strategy using a Smith predictor.