Abstract In recent years, the study and research on small magnetic robots, typically a few centimeters in size, have gained momentum due to the increasing demand for such robots in various applications. One of the primary uses of these robots is in the medical field. Inside the human body, due to limited accessible space and the desire to minimize invasive procedures such as surgeries, manual endoscopy, and others, capsule-shaped robots are employed. The movement mechanism of each robot is directly related to its operational environment; thus, the design and analysis of the movement mechanism can significantly impact the robot's performance. In this context, the aim of this research is to develop and analyze the theoretical and experimental dynamics of a capsule-shaped magnetic robot's movement and to control its open-loop motion on a viscoelastic substrate within a water-filled chamber. The magnetic robot in question can move inside a water-filled environment and on a viscoelastic substrate using the propulsive magnetic torque generated by a rotating magnetic field generator. The rotating magnetic field generator is designed as Helmholtz coils oriented perpendicularly along three axes to create a constant magnetic torque within the workspace. The resistant torque and force exerted by the fluid were initially obtained by considering the equivalent volume of the magnetic robot and employing analytical relationships. Subsequently, numerical methods were used to account for the robot's actual geometry, speed, and boundaries, and these results were compared with those derived from the equivalent volume method. The relationship between the resistant torque exerted by the viscoelastic substrate and the rolling speed of the magnetic robot was first derived based on Kelvin's theory for viscoelastic substrates. Then, using numerical methods, the amount of indentation into the substrate and the viscoelastic resistant torque acting on the micro-robot were estimated. Finally, the simulated forces and torques were incorporated into the governing equations of the magnetic robot's motion, and its movement was numerically simulated. The simulation results demonstrated the relationship between the kinematic and dynamic characteristics of the magnetic robot and the amplitude and frequency of the input current to the magnetic coils. At the end of this study, after describing the design and preparation of the required laboratory equipment for experimental eva‎luation, the planned experimental tests were conducted, and their results were compared with the simulation outcomes.

مهدي كشميري , سعيد ضيائي راد

مهدي سلماني تهراني , مرضيه مجدراصيل , شهرام هاديان جزي