Modeling of Underwater Snake Robots

Abstract

Abstract-Increasing efficiency by improving the locomotion methods is a key issue for underwater robots. Hence, an accurate dynamic model is important for both controller design and efficient locomotion methods. This paper presents a model of the kinematics and dynamics of a planar, underwater snake robot aimed at control design. Fluid contact forces and torques are modeled using analytical fluid dynamics. The model is derived in a closed form and can be utilized in modern model-based control schemes. The proposed model is easily implemented and simulated, regardless of the number of robot links. Simulation results with a ten link robotic system are presented.

Modeling and propulsion methods of underwater snake robots

“…In [1], [12], for a neutrally buoyant USR considering that the fluid is viscid, incompressible, and irrotational in the inertia frame and that the current is constant and irrotational in the inertial frame, it is shown that the fluid forces on all links can be expressed in vector form as…”

“…There are several models proposed for swimming snake-like robots. A discussion of the different modeling approaches proposed for USRs can be found in [5], [12]. This paper proposes a closed form model for USRs swimming in a 2D plane, which takes into account the extra propulsion forces acting along the body when the snake robot is equipped with different added effectors, such as a caudal tail, fins, stern propeller, and tunnel thrusters, in addition to the propulsion forces generated by the link angle motion together with the hydrodynamic forces.…”

“…This paper proposes a closed form model for USRs swimming in a 2D plane, which takes into account the extra propulsion forces acting along the body when the snake robot is equipped with different added effectors, such as a caudal tail, fins, stern propeller, and tunnel thrusters, in addition to the propulsion forces generated by the link angle motion together with the hydrodynamic forces. The model of a USM moving in a 2D plane presented in [1] modifies the kinematic equations and the equations of motion developed for a USR in [12] to accommodate the different mass and length of each link, and to take into account the forces from additional effectors. In this paper, the hydrodynamic model presented in [1] and [12] is extended to model the added mass effects more accurately, which then is combined with the kinematic model to derive a closed form model of the USR.…”

“…The model of a USM moving in a 2D plane presented in [1] modifies the kinematic equations and the equations of motion developed for a USR in [12] to accommodate the different mass and length of each link, and to take into account the forces from additional effectors. In this paper, the hydrodynamic model presented in [1] and [12] is extended to model the added mass effects more accurately, which then is combined with the kinematic model to derive a closed form model of the USR. In addition, analytical expressions for the fluid parameters, which take into account the different values of the fluid coefficients and geometry of each link, are derived.…”

Towards autonomous locomotion: Slithering gait design of a snake-like robot for target observation and tracking

“…Currently, a number of snake-like robots can achieve diverse locomotion, for instance, serpentine forward [2], roll to the sideways [3], climb along poles, and swim under water [4]. However, none of those snake-like robots can achieve autonomous locomotion, i.e., the capabilities to autonomously decide how, when, and where to move.…”