SUMMARY: This paper presents the results of a study on the dynamical modeling, analysis, and control of a spherical rolling robot. The rolling mechanism consists of a 2-DOF pendulum located inside a spherical shell with freedom to rotate about the transverse and longitudinal axis. The kinematics of the model has been investigated through the classical methods with rotation matrices. Dynamic modeling of the system is based on the Euler–Lagrange formalism. Nonholonomic and highly nonlinear equations of motion have then been decomposed into two simpler subsystems through the decoupled dynamics approach. A feedback linearization loop with fuzzy controllers has been designed for the control of the decoupled dynamics. Rolling of the controlled mechanism over linear and curvilinear trajectories has been simulated by using the proposed decoupled dynamical model and feedback controllers. Analysis of radius of curvature over curvilinear trajectories has also been investigated.

Limbless locomotion reveals increasing interest among locomotion methods inspiring mobile robots. This paper deals with the lateral undulation, one type of terrestrial snakelike locomotion. It represents the first part of a research project based on a biologically inspired approach. The purpose, in this first place, is to cover the physical principles involved in lateral undulation. Following an overview of the lateral undulation as it occurs in nature, the authors consider a generic planar mechanism and a related environment that suit to satisfy the fundamental mechanical phenomenon observed in the locomotion of terrestrial snakes. Application of a relatively simple control law is tested through dynamic simulations. In the second place, the results of this introductory study are going to be used in the research of an appropriate technological solution for an artificial snake exerting lateral undulation. The approach presented differs from other works on the subject in the sense that it does not require any wheeled structure.

The snake is represented by over 2500 species on earth. Widespread geographical distribution as well as a long history of evolution mean that they possess a relatively adaptive anatomy. This paper deals with snake-like locomotion that is distinguished from wheeled and legged locomotion by fundamental physical differences. A biologically motivated alternative locomotion for mobile robots is the aim of the project. A number of biological unknowns in the problem let us to make hypotheses based on heuristic approaches. Research on snake-like locomotion is motivated by several applications from inspection in hazardous environments to use as medical equipment.