Le Chesnay, France —Engineers and researchers working on the BIP 2000 bipedal walking robot discovered much about two-legged locomotion and stability. One day, their research may very well help enhance the lives of people with reduced mobility.
"What we learned helped us derive specific methods for coping with other types of stability based on unilateral constraints and contact forces," explains Bernard Espiau, research director, BIP project at INRIA, France's National Institute for Research in Information Technology and Automation that coordinated the project. In fact, Espiau claims that because the robot's dimensions and movement are based on human kinematics, analogous locomotion patterns and feedback control algorithms and architectures could be used in the future in electrostimulation techniques for human legs.
For muscle, engineers specified brushless dc motors and power supplies from Parvex. Dual actuators in parallel on each ankle and at the trunk use patent pending screw nuts with rollers. Potentiometers in every joint, synchro resolvers in every motor, three force sensors under each foot, a 2-axis inclinometer, and one acoustic range finder all provide the vital feedback to the controller.
The control system consists of on-board Parvex power units, a 68040 embedded CPU, an external transformer for the main power supply, an external Unix workstation, and VxWorks Real Time system software. But in addition to all that technology, a proprietary programming environment for verification and code generation of critical real-time systems (ORCAAD), was key to solving what was the biggest challenge of integration, according to Espiau. "By working with advanced design and simulation software before realization, we were able to develop a reliable prototype."