This is a robot which has the main form of pneumatic energy developed by the Graduate School of Information Science and Technology, University Tokyo, Japan. This robot has just exist following the IROS 2011 event which takes place this month in San Francisco.
PIGORASS is a pneumatically-driven quadruped robot developed by Yasunori Yamada, Satoshi Nishikawa, Kazuya Shida and Yasuo Kuniyoshi at the ISI lab (Intelligent Systems and Informatics Lab), the same lab that brought us the jumping robot
Mowgli and the running
Athlete Robot. Its skeleton (made of ABS resin and carbon-fiber-reinforced plastic), 10 artificial pneumatic muscles, and 10 passive spring muscles weigh only 4kg (8.8 lbs). Its total body length is only 35cm (13″) long. The artificial muscles are driven by an external air compressor, and pressure sensors and potentiometers replicate how real muscles sense their length and tension.
This robot has movements that are not programmed before, but it appears from the structure of the body and the nerve signal from the oscillator fluctuates each muscle by using what is called a model spinobulbar. Individual neurons that control muscles each of which can fire in pairs (alternate between front and rear legs) to do some sort of gallop, or be fired simultaneously to produce a jumping movement.
