As the name implies humanoid robot is nothing but a robot whose appearance is more or less similar to human being. A typical humanoid robot has a head, two hands and two legs. The male robots are called Androids and female robots are called Gynoids.

Humanoid robots are complex machines capable of travelling through formidable terrains. They are able to step over the obstacles on the way and can move in omni-directional manner. Unlike wheeled robots, these machines have increased versatality and agility. While walking, humanoid robots have to maintain balance. So coordination of many degrees of freedom is essential. These legged robots have to contact with the environment changes discrete and every move.

Examples
One of the first humanoid robots is ASIMO. It is a four foot tall android capable of interacting with humans by recognising moving objects, postures, gestures, sound and faces. Actroid is a Gynoid that looks like a Japanese woman. It can blink, breath and speak.

Challenges
1) Making the robot simulate a human’s facial expressions
2) Enabling it to walk on two legs
3) Getting it to adequately communicate with a human user.
4) Humanoid robots demand large scale investment