The paper deals with the dynamic modeling of bio-inspired robots with soft appendages such as flying insect-like or swimming fish-like robots. In order to model such soft systems, we propose to use the Mobile Multibody System framework introduced in [1], [2], [3]. In such a framework, the robot is considered as a tree-like structure of rigid bodies where the evolution of the position of the joints is governed by stress-strain laws or control torques. Based on the Newton-Euler formulation of these systems, we propose a new algorithm able to compute at each step of a time loop both the net and passive joint accelerations along with the control torques supplied by the motors. To illustrate, based on previous work [4], the proposed algorithm is applied to the simulation of the hovering flight of a soft flapping-wing insect-like robot (see the attached video).

Bio-inspired by moth or humming-birds, several micro air vehicles (MAV) have recently been developed. In these systems, the motion of the lifting surface is complex and modeled by flapping motion-controlled soft wings. The synchronization of the actuated periodic flapping motion of the wings and that of passive twisting degrees of freedom (dof) allows producing hovering flight. Depending on the feature of the MAV such as stiffness, and geometric characteristic, hovering flight can be naturally stable or not. In the first case hovering is obtained via an open loop control (or a local closed loop control) while in the second case a global control strategy is required to achieve the same objectives. Thus, it is crucial to take into account the influence of the design of the MAV on the control in order to choose an appropriate morphology that can reduce the burden of control. In this paper mathematical tools and methodologies are proposed to achieve this objective and reduce the computational cost of control.

In the context of underwater robotics, positioning and coordination of mobile agents can prove a challenging problem. To address this issue, we propose the use of electric sensing, with a technique inspired by weakly electric fishes. In particular, the approach relies on one or several of the agents applying an electric field to their environment. Using electric measures, others agents are able to reconstruct their relative position with respect to the emitter, over a range that is function of the geometry of the emitting agent and of the power applied to the environment. Efficacy of the technique is illustrated using a number of numerical examples. The approach is shown to allow coordination of unmanned underwater vehicles, including that of bio-inspired swimming robotic platforms.

In this paper, we present a unified dynamic modeling approach of (elongated body) continuum robots. The robot is modeled as a geometrically exact beam continuously actuated through an active strain law. Once included in the geometric mechanics of locomotion, the approach applies to any hyperredundant or continuous robot that is devoted to manipulation and/or locomotion. Furthermore, by the exploitation of the nature of the resulting model of being a continuous version of the Newton-Euler model of discrete robots, an algorithm is proposed that is capable of computing the internal control torques (and/or forces), as well as the rigid net motions of the robot. In general, this algorithm requires a model of the external forces (responsible for the self-propulsion), but we will see how such a model can be replaced by a kinematic model of a combination of contacts that are related to terrestrial locomotion. Finally, in this case, which we name “kinematic locomotion,” the algorithm is illustrated through many examples directly related to elongated body animals, such as snakes, worms, or caterpillars, and their associated biomimetic artifacts.

This paper reports the first results from a program of work aimed at developing a swimming robot equipped with electric sense. After having presented the principles of a bioinspired electric sensor that is now working, we will build the models for electrolocation of objects that are suited to this kind of sensor. The produced models are in a compact analytical form in order to be tractable on the onboard computers of the future robot. These models are tested by comparing them with numerical simulations based on the boundary elements method. The results demonstrate the feasibility of the approach and its compatibility with online objects electrolocation, i.e., another parallel program of ours.

The paper deals with the modeling of a fish-like robot equipped with the electric sense, suited to study sensorimotor loops. The proposed multi-physics model merges a swimming dynamic model of a fish-like robot with an electric model of an embedded electrolocation sensor. Based on a TCP-IP and threaded framework, the resulting simulator works in real time. After presenting the modeling aspects of this work, this article focuses on two numerical studies. In the first, the interactions between body deformations and perception variables are studied and a current correction process is proposed. In the second study, an electric exteroceptive feedback loop based on a direct current measurement method is designed and tested for obstacle avoidance.

In this paper, a multi-variable feedback design for the 3D movement of an eel-like robot is presented. Such a robot is under construction in the context of a national French robotic project. The proposed feedback enables the tracking of a desired 3D position of the eelpsilas head as well as the stabilization of the rolling angle. The control design is based on a recently developed reduced model that have been validated using a 3D complete continuous model described in [3]. Several scenarios are proposed to assess the efficiency of the proposed feedback law.

This paper proposes a dynamic model of the swim of elongated fish suited to the online control of biomimetic eel-like robots. The approach can be considered as an extension of the original reactive ldquolarge elongated body theoryrdquo of Lighthill to the 3-D self-propulsion to which a resistive empirical model has been added. While all the mathematical fundamentals have been detailed by Boyer . (http://www.irccyn.ec-nantes.fr/hebergement/Publications/2007/3721.pdf, 2007), this paper essentially focuses on the numerical validation and calibration of the model and the study of swimming gaits. The proposed model is coupled to an algorithm allowing us to compute the motion of the fish head and the field of internal control torque from the knowledge of the imposed internal strain fields. Based on the Newton-Euler formalism of robot dynamics, this algorithm works faster than real time. As far as precision is concerned, many tests obtained with several planar and 3-D gaits are reported and compared (in the planar case) with a Navier-Stokes solver, which, until today have been devoted to the planar swim. The comparisons obtained are very encouraging since in all the cases we tested, the differences between our simplified and reference simulations do not exceed 10%.

This paper relates recent advances in the design of feedback laws for the 3D movement of an Eel-like robot. Such a robot is under construction in the context of a national French robotic project. The proposed feedback enables the tracking of a desired 3D position of the Eel head as well as the stabilization of the rolling angle. A velocity controller is also proposed. The controller is tested on a recently developed complete 3D model in order to assess its efficiency in tackling 3D manoeuvres.

This paper presents the dynamic modeling of a continuous three-dimensional swimming eel-like robot. The modeling approach is based on the "geometrically exact beam theory" and on that of Newton-Euler, as it is well known within the robotics community. The proposed algorithm allows us to compute the robot's Galilean movement and the control torques as a function of the expected internal deformation of the eel's body