Development of a lightweight biped adult-size humanoid robot with connecting lever structure in RoboCup

The humanoid robot is a popular research topic in robotics. Especially, how to make the robot more like a human being not only behavior but also body structures always has been the main researching direction of all developers. However, before they started to research the kinematics and algorithm. Developers have to invest a huge amount of money in order to build the hardware. As a result, many developers without resource, can only work in simulation, not real robots. In this project, we are going to build legs of an adult-size humanoid robot (about 90cm height). In our design, the legs use a connecting lever structure that works similarly to the human muscle to deliver the force. In order to design the lightweight legs and feet, we also set up most of the heavy items compress around the hip part. The heavy hip approximate to human's core muscle group, it can be used to support the upper-body, keep balancing, drive the legs and reduce the load of the lower limbs. Therefore, our robot doesn't need to have strong or heavy limbs and is more human like. Eventually, we design and build the robot with lightweight legs and easy control center of mass. This helps us to reduce the strength of the servo motor and use low-cost servo motor only. We built humanoid robot legs with a weight of around 10 kg and 12 degrees of freedom. It only requires ten 60 kgf-cm and two 40 kgf-cm servo motors. The robot can accomplish the walking motion forward.