Motion planning of particle based microrobots for static obstacle avoidance

Magnetic microrobots have been shown to be effective at navigating microscale environments which has led to many investigations reguarding the motion control of microrobots. To increase the feasibility of using microrobots for microscale tasks and widen the range of potential applications, the use of autonomous navigation systems will be essential. In this work, the magnetic particle based achiral microrobots are controlled wirelessly using a combination of rotating and static magnetic fields generated from electromagnetic coils in an approximate Helmholtz configuration. In previous work, we developed both a kinematic model for particle based microrobots and a feedback controller; once implemented, the controller can guide the microrobots to any goal positions. In the present work, we demonstrate path planning motion control for magnetic particle based microrobots in microfluidic channels formed using patterned static SU-8 microstructures. The microrobots were able to avoid collision with the microstructures, which acted as static obstacles, by using a gradient path method. In experiments, microrobots were able to reach the final goal position by following waypoints of generated path from the gradient path method in a static obstacle laden environment.