Pneumatic Air Muscle and Pneumatic sources for light weight autonomous robots

Faced with the challenge of making running speed robots, improved light weight actuation is a primary concern. Pneumatic Air Muscle (PAM) has not been advanced significantly since their conception and some new features are needed to meet compact bi-pedal robots. Driven by air pressure, all PAMs require air control valves that ideally are light weight, low power and provide high flow rates for rapid contract-relax cycling. PAMs require air compressors and air reservoirs. These are normally very heavy and very bulky. A new approach to both the PAM and air valves is presented in this paper with a view to enabling the design of compact, lightweight and dynamic robots. Similarly a totally new way of generating pneumatic pressure is presented based on heat engine methods. The improvements are described and the advantages, method of operation and method of implementation in a bi-pedal robot are discussed. Initial analysis is presented for the actuation force characteristic, isometric and isotonic behaviors of the muscles and flow rate for the valves. The heat engine based actuator is explained covering the design choices and the early results of a working prototype is described. The heat engine work capacity and efficiency is contrasted to that of standard air compression.