Active compliance control structure design for a robotic-grinding machine

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2017
Dönder, Abdülhamit
Grinding operation has an advantage of precise form shaping in machining processes. However, if the surface profile is not known before the machining process, it is hard to obtain an accurate surface profile using a grinding operation. In this work, a novel method to compensate the form shaping errors in grinding operations due to the lack of a priori knowledge of the surface profile will be presented. Grinding operation on a workpiece with an unknown surface profile is aimed. Compliance force control is implemented by means of admittance control in two degrees of freedom using a piezo actuator and a hexapod parallel manipulator. The desired force interaction between the tool and the workpiece was achieved by imposing an offset from the preset depth of cut. Additionally, tool deflection due to the grinding forces of the robotic grinding setup is taken into consideration. The deflections are computed from the grinding forces in real time and the compensation is performed by the hexapod robot in six degrees of freedom. Based on the literature review, this is the first study in which grinding on a workpiece with an unknown surface profile was performed while tool deflection due to the grinding forces was compensated. Two different control algorithms namely PID control and Active Disturbance Rejection Control were tested on a robotic grinding setup and the experiment results are discussed. 
Citation Formats
A. Dönder, “Active compliance control structure design for a robotic-grinding machine,” M.S. - Master of Science, Middle East Technical University, 2017.