Design of a Controller for a Precision Positioning Machine

System identification was used to build an accurate model of a high-precision measurement system. The model built by system identification was compared to modeling by first laws and showed extremely similar results. Pole-placement control design based on the identified system was used to place the systems\u27 dominant poles. The necessary gains to achieve the desired system response were determined by using the identified model and knowledge of the controller structure. The performance of the model-based controller was compared to actual data of the system and showed that control based on the identified model can be used to accurately control the precision measuring machine

Automated Digital Machining for Parallel Processors

When a process engineer creates a tool path a number of fixed decisions are made that inevitably produce sub-optimal results. This is because it is impossible to process all of the tradeoffs before generating the tool path. The research presents a methodology to support a process engineers attempt to generate optimal tool paths by performing automated digital machining and analysis. This methodology automatically generates and evaluates tool paths based on parallel processing of digital part models and generalized cutting geometry. Digital part models are created by voxelizing STL files and the resulting digital part surfaces are obtained based on casting rays into the part model. Tool paths are generated based on a general path template and updated based on generalized tool geometry and part surface information. The material removed by the generalized cutter as it follows the path is used to obtain path metrics. The paths are evaluated based on the path metrics of material removal rate, machining time, and amount of scallop. This methodology is a parallel processing accelerated framework suitable for generating tool paths in parallel enabling the process engineer to rank and select the best tool path for the job

Electric Poling-assisted Additive Manufacturing Process for Lead-free Piezoelectric Device Fabrication

AbstractThis paper presents a new additive manufacturing method based on electric poling process often used in many polymeric materials processing for lead-free piezoelectric device fabrication. This is to directly and continuously print piezoelectric devices from Polyvinylidene fluoride (PVDF) polymeric filament rods under a strong electric field and mechanical stretching along the filament core. Piezoelectric devices were fabricated and its crystalline phase transition was measured by using the Fourier transform infrared spectroscope. The results demonstrate that increasing the electric field increases the piezoelectric crystalline phase transitions and results in a device with higher current output under stress. This technique can be used to fabricate fully 3D freeform structured piezoelectric devices for sensing, actuator and energy harvesting applications with a simple, low cost, integrated processing and fabrication step