Sliding Mode Control of Low Cost Pressure Sensor Calibration Device

Low-cost pressure sensors are used for various purposes, but it have unique properties such as hysteresis characteristics and creep characteristics. Therefore, it should be calibrated according to the purpose of use. For this purpose, a calibration device capable of applying a precise and repetitive load was generated. The core performance required for the calibration equipment is force control which can accurately apply the target load. However, since the material that contacts the end-effector of the equipment is a rigid body, it is difficult to control due to its high-speed response characteristics, so a robust and stable sliding mode force controller have to be applied. To design the sliding mode force controller of the calibration equipment, dynamic model of the system was derived, and system identification was performed. In order to improve the performance of the system identification, system model was modified by applying the nonlinear model to the system similar to the Hammerstein model. We applied a nonlinear model compensator to the system model and designed sliding mode force control. To verify the performance of the designed controller, force control was applied to static and dynamic loads. It is confirmed through the verification experiment that the proposed sliding mode force controller has sufficient control performance.