Legged robots are robots that use their legs to move. Although wheeled robots are generally preferred due to their simple locomotion methods and designs, legged robots are more skilled in implementing complex actions than their wheeled counterparts. While wheeled robots need extra mechanisms to pass obstacles, legged robots can easily pass obstacles by changing their gait depending on the obstacle position. For that reason they have a great advantage over their wheeled counterparts on rough terrains although they have more complex designs and harder design processes.
Legged robots can be classified based on their leg count. Two legged humanoid robots, four legged quadruped robots and six legged hexapods are most common legged robot types. Although they don’t have much application, there are three and five legged robots, too.
Legged robots can implement different moving gaits depending on their leg count. For two legged humanoid robots, balance is an important issue and they need different considerations in locomotion control for keeping in balance. Four legged robots are statically balanced. They can implement periodic static moving gaits, but these methods are not energy-efficient. These robots generally implement control methods that control each leg individually to keep moving and in balance. Six legged hexapods don’t have much problem in terms of balance, so they implement static and periodic locomotion gaits and their control methods are generally easier than that of two legged humanoid robots or four legged quadruped robots.