Force Feedback Control in Material Testing Applications

Abstract

In micro- and nano scale material testing applications, the force control has been significantly used for stable and accurate manipulation. This thesis introduces new application area of the force feedback control in the tensile testing of the micro-scale fibrous materials. Specifically, the force feedback controller is implemented in existing open loop microrobotic platform which simply consists of two clamps. One clamp is driven by a M.111.1 DG Micro-translation stage and the other is connected to a force sensor of FUTEK LPM200 panel mount load cell. The force controller performs to control the tensile force of micro-scale fibrous materials pulled by one clamp and to measure pulling force by the force sensor installed on the other clamp. By doing so, it can obtain more exact data of mechanical property of the micro-scale fibrous materials depending on the input target force. For the implementation of the force feedback controller, the conventional Proportional Integral Derivative (PID) and Proportional-Integral (PI) controls are used for the tensile test simulation due to its simple structure and design, low cost and high performance. A computer model of the microrobotic platform is built based on its mathematical models. In order to find usable controller parameters, conventional rule based tuning methods such as Ziegler Nichols, Pessen Integral of Absolute Error (PIAE), Some overshoot rule (SO-OV) and No overshoot rule (NO-OV), and Simulink PID tuner are utilized for the computer model. Finally, the force feedback controller is applied to the real microrobotic platform to compare the differences of the behaviors of the open loop system and the force feedback control system as the closed loop.