Development of the Orthogonal Micro Robot for Accurate Microscopic Operations

In this paper, we describe development of an orthogonal micro robot for accurate microscopic operations. In order to provide microscopic operation, the simple locomotion mechanism which is composed of one piezoelectric actuator and two U-shaped electromagnets is proposed. Here two U-shaped electromagnets guided by a pair of v-grooves are connected by a piezoelectric actuator so that it can move in one axis precisely. This simple one-axis micro robot moves like inchworm with less than 100 nm resolution. We attach permanent magnets on the electromagnets so that this robot can fix itself on a steel surface even if we do not apply the current to electromagnets. In order to provide XY orthogonal positioning, we connect one micro robot to another micro robot orthogonally. In order to realize cell-processing, we attach the three orthogonal micro robots on an inverted microscope. Here we attach a micro pump to a left micro robot to hold biological samples such as an egg cell. We attach another micro pump to a right micro robot to inject to biological samples. We arrange another micro robot between other two micro robots to position samples. The whole cell-processing device is very small, so we can easily attach the whole device to micro processing instruments. We have developed the special control software with visual feedback control so that each motion could be controlled by a simple mouse click on a PC or joysticks. In experiments, we demonstrated to hold an egg cell whose diameter is 100 mum and inject the pipette whose diameter is 5 mum to the egg cell under the collaboration of these orthogonal micro robots. We have confirmed that this unique micro robotic device has much of potential for actual use to various micro manipulation, such as artificial inseminatation and positioning of miniscule parts of portable devices. The design procedure, basic performance and collaboration with versatile micro robots are also discussed to open the new field for micro-robotics in pre- cision region.