Kinematics and Control of an omni-directional mobile microrobot for a micro-factory

his paper presents the Kinematics and control of an omni-directional mobile microrobot for micro-assembly in a micro-factory. The millimeters size microrobot is approximately 9 mm in length, 9 mm in width and 6 mm in height. It has three normal wheels which are connected with each other through a set of micro gears. Through a kind of special steering structure, the microrobot wheels can steer together with the same steering angles. A micro gripper is mounted on the top of the microrobot chassis, and can be turned with the front wheel synchronously. Through analyzing the rank of the kinematic matrix, the mobility freedom and steering freedom are calculated to demonstrate the omni-directional characteristic of the microrobot. Further, the microrobot and the micro gripper kinematic models are derived. Using these models, simulations show the relation between the microrobot movement situation and the control input. The microrobot is guided by an external vision system and controlled by a circuit board connected to the microrobot by flexible ultraminiature wires. Experiment results demonstrate the movement flexibility of the microrobot and the validity of the whole control system.