Cockroach Milli-Robot With Improved Load Capacity

In the field of milli-robots, several methods of constructing robots by laminating materials and then folding have been developed. Among these methods, smart composite microstructures (SCM) is widely used for making lightweight small mobile robots. However, in the case of a robot manufactured by the SCM method, due to flexible and easily deformable links and joints, it is often difficult to obtain proper kinematic movement due to deformation of the structure when a heavy load is applied. In this paper, studies on the mechanism design and manufacturing were carried out to increase the load capacity of robots manufactured by SCM. First, we modified the kinematics of the robot to reduce off-axis loading on flexure joints by using a planar 6 bar leg mechanism, which was fabricated using a new multilayer SCM process. Second, the fabrication process is improved to reduce peeling of laminate structures by introducing integrated rivets at joints. Finally, alternative materials, such as balsa, are used. To verify the design and fabrication improvements, we compared the payloads after applying the proposed methods to an existing cockroach robot design. Compared to the previous design, speed with a 50-g payload increased from 7 to 30 cm per second.