Abstract
We developed an two-wheeled insect-sized robot to evaluate odor source localization algorithms of the male silkmoth (Bombyx mori). For fast and stable acquisition of sensory information, we used atmospheric ions and ion sensors to simulate odorant catch by insect olfactory sensors. The robot has two ion sensors, and a microcomputer for processing the sensor output, motor control and communication with external devices. To minimize its size, we used two modified servomotors as actuators, which enabled the robot to move in the same manner as a walking silkmoth. We used wheel encoders for feedback control of wheel position. The encoder output can also be used as a simulation of optic flow, which is necessary for speed and turn control in insect locomotion. By employing the robot, we evaluated the performance of two odor source localization models: one is based on the fixed programmed behavior of the silkmoth and a second model additionally includes course control dependent on the amplitude difference of ion sensor output on opposite sides of the robot. The results indicate that the robot based on the latter model was superior in ion plume tracking. Further evaluations of algorithms using our insect-sized robot will be an important tool for understanding behavioral mechanisms of orientation and applying them to robotics.
