BILL-LEGS: Low computation emergent gait system for small mobile robots

For almost two decades, Holk Cruse's leg coordination method has been used as a control basis for generating gaits in legged robots. His stick insect inspired method has been successfully implemented for a number of robots such as Robot I and Robot II, the TUM Walking Machine, Tarry II, and BILL-Ant-p. However, some engineers have had difficulties implementing the controller when trying to select robust mechanism influence weights that are immune to variations in starting pose and leg speed. Additionally, the coordination method can be overwhelming for low- computation capable microcontrollers preferred for small, untethered mobile robots. The Biologically-Inspired Legged Locomotion-Low computation Emergent Gait System (BILL-LEGS) was developed as a solution to some of these issues. This method borrows heavily from Cruse's original design with some modifications that allow it to be implemented on small, autonomous legged robots using simple microcontrollers. This paper describes the BILL-LEGS method and its performance during simulation. Additionally, data are presented that show its robustness to mechanism weight selection and its generation of stable gaits, independent of leg starting positions and leg movement speeds.