Currently, research into mobile robots is actively underway worldwide. Mobile robots can be divided into robots that move with wheels that touch the ground and robots that walk with legs.

In this study, a four-legged walking robot with legs is selected so that it can be applied to different surfaces, and studies on gait, structure and control were reviewed, with a greater emphasis on stable walking.

What is important about walking is to ensure stability so that the center of gravity (or ZMP) is within the polygon formed by the legs supporting the ground. For this purpose, a mathematical model for kinematics and inverse kinematics suitable for the robot's leg joints was established. The motion trajectories of the torso and each foot were generated using third or higher order functions, and the angular values of each leg joint were obtained through their relative motion and an inverse kinematics model programmed in MATLAB.

The angular value obtained as above was applied to ADAMS, a dynamics simulation software, in the form of a spline. The ADAMS model used at this time was constructed by importing 3D CAD CATIA data from an actual produced dog-shaped robot, creating constraints and joints for each joint and providing contact relationships between the toes and the ground. ADAMS simulation results confirmed that the planned walking pace was sufficiently stable.

These gait patterns were again applied to the robot itself to confirm its walking ability, and the distance sensor was installed to improve the robot's navigation ability by equipping it with obstacle detection and response capabilities.

Keywords

ADAMS, 3D CAD, robot, four leg and motor