Uncalibrated trajectory following with magnetically controlled microrobots

Microrobot systems have demonstrated potential in the areas of manipulation, assembly, and therapeutic tasks at the microscale. This paper investigates uncalibrated visual servoing of microrobot devices in a fluidic environment. Planar actuation is achieved with four electromagnets, and both point-to-point motion and trajectory following are demonstrated. The unique contribution of this paper is the implementation of a dynamic recursive least squares estimation algorithm that is used to control the device as it follows a desired path without any calibration or training steps. Tracking accuracy on the order of 1.6 pixels (10.5μm) is demonstrated for a 200μm diameter microrobot. Initial trials successfully achieved micromanipulation of both 50 and 200μm glass beads.