Animal Locomotion and Robotics

Legged animals typically employ multiple gaits, i.e., phase-locked patterns of limb movements, for terrestrial locomotion. The control of animal locomotion involves a central pattern generator (CPG), which is an intraspinal network of neurons capable of producing rhythmic output. Over the past few decades, mathematicians and engineers have become increasingly interested in animal gaits and locomotor CPGs. This interest has largely been motivated by the need for developing control systems for multi-legged robots. Machines capable of legged locomotion are an attractive option, because they can be used to explore rough and uneven terrain, which is often inaccessible to wheeled vehicles. However, the control of such devices, and in particular the coordination of a large number of legs, poses a difficult technical problem. Engineers and mathematicians have increasingly turned to biology for inspiration, on the assumption that biological evolution has led to optimally-designed control mechanisms for legged locomotion. In this area, contemporary topics of interest include:

1. the role of symmetry and symmetry-breaking in the generation and control of gait patterns
    
2. the relationship between gait transitions and bifurcations of various kinds
    
3. coupled nonlinear oscillators and locomotor CPGs
    
4. the stability of various gait patterns and their associated phase-locked oscillation patterns
    
5. design and control issues for ``statically-stable" versus ``dynamically-stable" legged robots
    
6. the effects of noise, feedback gains, and control-loop time delays on the stability of gait patterns
    
7. emergent dynamics arising from the interactions between neural (electronic) elements, mechanical elements, and the environment
    
8. design and control issues for microrobots
    
9. "top-down" versus "bottom-up" approaches to the control of legged robots
    
10. "passive" versus ``active" control of legged robots
     
11. hierarchical control of locomotion