Insect Designs for Improved Robot Mobility

SYNOPSIS: The biorobotics group at CWRU follows a strategy of close interaction between engineers and neurobiologists to create improved robot designs and gain insights into neural control of legged locomotion. A series of legged vehicles has been developed. The first 2 robots were not based upon a particular insect. Robot I walked with insect gaits using network controllers. Robot II walked on irregular terrain using a distributed controller with localized reflexes. The third in this series, Robot III, is more powerful and benefits from the joint and leg designs of cockroach, but is scaled 17 times larger. A small hybrid wheel-leg autonomous robot has also been developed with inspiration from cricket. The implementation of cockroach-like mechanics into Robot III resulted in animal-like posture and leg movements. The efforts to control the complex mechanics of this robot have led to hypotheses and insights into the neural basis of insect locomotion. High-speed video records of cockroaches performing locomotory tasks were used to determine the essential joint designs and motions for each leg. Leg movements were recorded during walking on a treadmill, turning and climbing over relatively high barriers. These data were incorporated into a dynamic simulation that predicted appropriate values for design. Actuators were sized according to the predicted joint torques. The entire structure of the robot was designed according to the predicted loads. Robot IV is currently being constructed and it will be dynamically similar to cockroach. It shares the leg kinematics and size of Robot III, but its actuators give its joints some important muscle -like properties such as tunable passive stiffness. This passive joint stiffness will provide the robot with energy efficiency. We have constructed a hybrid wheel-leg microrobot with rear legs inspired by those of cricket and two front wheels. The robot has its power system and locomotion controller on board. Others in our group have developed microvalves using a MEMS fabrication process to distribute compressed air to the robot’s actuators. The escape response circuit in cockroach has been mapped and modeled and adapted for use as a crash avoidance system for cars. We have shown it to be effective in simulation and in a model car equipped with sonar sensors.