|Fuzzy Time Delay Algorithms for Position Control of Soft Robot Actuated by Shape Memory Alloy
Junfeng Li* and Yunyao Pi
International Journal of Control, Automation, and Systems, vol. 19, no. 6, pp.2203-2212, 2021
Abstract : Due to the nonlinear saturated hysteretic behavior of SMA during the phase transformation, it is not easy to achieve accurate position tracking control by establishing an effective controller for the SMA actuator system. In this paper, an accurate position control method based on fuzzy time delay algorithms for a soft robot is proposed. The error of TDE is unavoidable because the smallest value for the time delay is the sampling time of the microcontroller, a rule-based fuzzy logic controller for online gain tuning combined with TDC is proposed to eliminate the position control errors. Three different sets of experiments are conducted, using step, sine and ramp signals as reference inputs. The experimental results demonstrate that the proposed method has the smallest steady state error and the least overshoot than TDE and PI controller. In conclusion, the proposed method should be a viable alternative for position control of SMA actuator.
Fuzzy time delay algorithms, position control, SMA, soft robot.