Abstract

In recent years, Magnetic Soft Continuum Robots (MSCRs) have gained significant attention partly due to their promising applications in sensitive and precise biomedical tasks, such as targeted drug delivery and minimally invasive treatments. These applications benefit from the unique multimodal locomotion of MSCRs and their wireless actuation capabilities. MSCRs typically undergo large deformation when subjected to magnetic fields. However, there are very limited studies on characterizing their nonlinear hysteresis behavior, especially in fluid environments subjected to varying magnetic field. This study attempts to experimentally investigate the real-time nonlinear and hysteretic behaviors of an MSCR (designed as a cantilever beam made of magnetoactive elastomer) fully submerged in a fluid environment. The MSCR's behavior is explored under both DC and AC magnetic intensities. In AC scenarios, the robot experiences a high oscillatory magnetic field, ranging from 5 to 25 mT, and is subjected to frequencies as high as 5 Hz. To generate a uniform and precise magnetic field, a hardware-in-the-loop experiment employing a feedforward-PID controller was designed. The experimental data were subsequently analyzed to realize the MSCR's response time histories and hysteretic responses. Keywords-magnetic soft robot; feedforward-PID control algorithm; hardware-in-the-loop experiment; large deformation; high-frequency oscillatory movements.