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An innovative design of a polyurethane microgripper system with force sensor is developed for the measurement of gripping force in vision-based control. A microgripper mechanism integrated with a force sensing arm is fabricated by an excimer laser. The microgripper is actuated by a self-biased-SMA (Shape Memory Alloy) actuator. A computer-vision method through the ERES (Extended Regional Edge Statistics) algorithm is employed to track the motion of gripper. The position information of the gripping point together with the deflection of the force sensing arm is utilized for sensing force. A fuzzy expert with a PI controller in a visual servo is employed to test the performance of sensing the gripping force in grasping of 38μm diameter metal rod. In the performance test, the microgripper system provides a maximum gripping size of 40μm, a maximum force resolution of 1μN and a maximum gripping force of 58μN.

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During micro electrochemical machining process, the gap between tooling and workpiece is dynamically and mutually influenced by multiple machining parameters, which include machining voltage, feed rate, electrolyte flow rate and others. Once inter-electrode gap could not be kept easily with a stable distance due to spark or short-circuit situation maybe happened to damage the cathode. Hence, it is needed to have a real-time protection function embedded within the μECM machining controller. The study of the short-circuit protection module for electrochemical machining is based on field programmable gate array (FPGA) system architecture. The advantages of the digital logic FPGA chips are programmable, high-response and stable operation, custom development and combination of multiple functions with Silicon Intellectual Property. It can achieve special process control or operation analysis logic to meet specific application requirements process equipment control, logic processing and signal analysis. Through the design and application technology of the digital logic FPGA chip, we can develop customized and combine of multiple functions with Silicon Intellectual Property. These silicon intellectual properties combined with the soft-core embedded processors can form the system on programmable chip control module. With a variety of Silicon Intellectual Properties restructuring integration and use of FPGA programmable features that can programmable short-circuit protection logic for electrochemical machining. This module combines power signal capture circuit device, and continuing to capture current signals during electrochemical machining process. The current signals via analog to digital converters and digital filtering, and based on the selection of the short-circuit logic electrochemical determine whether the establishment of short-circuit conditions. When a short circuit occurs, the module can react immediately turn off the power supply, to protect the machining electrode and enhance precision machining.