One of the most significant advantages of humanoid robots with respect to other mobile robots is their ability to walk on terrains with various characteristics. Making steps without changing the upper body posture, humanoid robots are capable of passing over different ground surfaces, i.e. compliant surfaces, slippery surfaces, rough terrains, and etc. Despite the fact that walking is a very simple task for human beings, realizing walking patterns on the humanoid robots in real environment is a demanding task. This is due to the unactuated DOF between the robot feet and the ground surface which makes the robot vulnerable to lose its balance. Walking would be even a more severe task, when the humanoid robot has the height and weight similar to a mature man. For a humanoid with such specifications, so many problems arise during walking, while these problems would not exist during working with a kid-size humanoid.
SURENA III is capable of walking with various step lengths and walking speeds on different surfaces in terms of terrain characterization. The step length may change from 0 cm (on spot) to 50 cm during walking, while the maximum walking speed is 0.7 km/h. This generation of SURENA is 7 times faster than the last version, SURENA II. This walking speed is safe for the final version of the robot, while the walking speed 1 km/h has been reached by the bipedal robot without the arms and the body cover. The robot can change its speed as well as step length during walking, based on the commands received from the high level control unit.