title: Path following control of planar snake robots using virtual holonomic constraints: theory and experiments.
abstract: This paper considers path following control of planar snake robots using virtual holonomic constraints. In order to present a model-based path following control design for the snake robot, we first derive the Euler-Lagrange equations of motion of the system. Subsequently, we define geometric relations among the generalized coordinates of the system, using the method of virtual holonomic constraints. These appropriately defined constraints shape the geometry of a constraint manifold for the system, which is a submanifold of the configuration space of the robot. Furthermore, we show that the constraint manifold can be made invariant by a suitable choice of feedback. In particular, we analytically design a smooth feedback control law to exponentially stabilize the constraint manifold. We show that enforcing the appropriately defined virtual holonomic constraints for the configuration variables implies that the robot converges to and follows a desired geometric path. Numerical simulations and experimental results are presented to validate the theoretical approach.
authors.affiliation: Department of Engineering Cybernetics, Norwegian University of Science and Technology (NTNU), Trondheim, 7491 Norway.
authors.forename: Ehsan
authors.initials: E
authors.lastname: Rezapour
authors.affiliation: Department of Engineering Cybernetics, Norwegian University of Science and Technology (NTNU), Trondheim, 7491 Norway.
authors.forename: Kristin Y
authors.initials: KY
authors.lastname: Pettersen
authors.affiliation: Department of Engineering Cybernetics, Norwegian University of Science and Technology (NTNU), Trondheim, 7491 Norway ; Department of Applied Cybernetics, SINTEF ICT, Trondheim, 7465 Norway.
authors.forename: Pål
authors.initials: P
authors.lastname: Liljebäck
authors.affiliation: Department of Engineering Cybernetics, Norwegian University of Science and Technology (NTNU), Trondheim, 7491 Norway.
authors.forename: Jan T
authors.initials: JT
authors.lastname: Gravdahl
authors.affiliation: Department of Engineering Cybernetics, Norwegian University of Science and Technology (NTNU), Trondheim, 7491 Norway.
authors.forename: Eleni
authors.initials: E
authors.lastname: Kelasidi
keywords: Biologically inspired robots; Path following; Snake robots; Virtual holonomic constraints