CPG-based LOCOMOTION. Robotics Course. Lesson 23. Legged Robot Locomotion Control. Legged Robot Locomotion Control CPG-and-reflex based Control of Locomotion. Locust Behavior. Leg Coordination: A number of local rules suffice for different gaits like tripod or tetrapod to emerge.
articulated rigid body with spring-and-damper muscles
A model of the body is essential for understanding locomotion control
Automatic setting of network parameters
Quadruped locomotion: walk, trot, gallop/bound, pace
Biped locomotion: walk (at least one leg on the ground at all times), running
Dynamically stable gait: the center of mass is maintained over the support area only in average
If the limit cycle is stable, the states of the system will return to it after perturbations
Design a locomotion controller inspired by the salamander CPG for the control of an amphibious robot
6 open coupling parameters
Motoneuron signals: mi = max(xi, 0)
We need not have knowledge of the biology to define a fitness function that gives rise to efficient and robust locomotion. A fitness function that rewards fast forward motion might suffice.
If we wanted to model a real salamander, we are in for a disappointment. The neural network that evolved bares little resemblance to the biological one.
The salamander can:
Central Pattern Generating Neural Networks (CPGs):
Small, relatively simple
neural systems with
well-defined circuitry, and well-defined function
Such central pattern generators are believed to be responsible for practically all known muscle behaviour.
In “simple” motor systems (insects, molluscs, crustacea), central pattern generators have identical architectures in all animals of the same species.
They are typically distributed throughout the body and form a distributed coordinated network of activity.
They also receive high level instructions from the brain and feedback from the low-level muscles.
The salamander model, while it is ‘high level’ its fitness function, is based on a simulation of CPGs and muscles.
National Univ. of Electro-Communications