Philippe Bidaud

An overview of 3D object grasp synthesis algorithms

This overview presents computational algorithms for generating 3D object grasps with autonomous multi-fingered robotic hands. Robotic grasping has been an active research subject for decades, and a great deal of effort has been spent on grasp synthesis algorithms. Existing papers focus on reviewing the mechanics of grasping and the finger-object contact interactions Bicchi and Kumar (2000) [12] or robot hand design and their control Al-Gallaf et al. (1993) [70]. Robot grasp synthesis algorithms have been reviewed in Shimoga (1996) [71], but since then an important progress has been made toward applying learning techniques to the grasping problem. This overview focuses on analytical as well as empirical grasp synthesis approaches.

Stability and Traction Optimization of a Reconfigurable Wheel-Legged Robot

Actively articulated locomotion systems such as hybrid wheel-legged vehicles are a possible way to enhance the locomotion performance of an autonomous mobile robot. In this paper, we address the control of the wheel-legged robot Hylos traveling on irregular sloping terrain. The redundancy of such a system is used to optimize both the balance of traction forces and the tipover stability. The general formulation of this optimization problem is presented, and a suboptimal but computationally efficient solution is proposed. Then, an algorithm to control the robot posture, based on a velocity model, is described. Finally, this algorithm is validated through simulations and experiments that show the capabilities of such a redundantly actuated vehicle to enhance its own safety and autonomy in critical environments.

Synthesis of complex humanoid whole-body behavior: A focus on sequencing and tasks transitions

We present a novel approach to deal with transitions while performing a sequence of dynamic tasks with a humanoid robot. The simultaneous achievement of several tasks cannot be ensured, so we use a strategy based on weights to represent their relative importance. The robot interacts with a changing environment, and the input torques are different depending on whether the robot performs tasks in a constrained state (e.g. in contact) or not. We develop a solution with smooth weights variations and transitional tasks which avoids sharp torque evolutions. In order to validate this approach, simulations are carried out on a virtual iCub robot which is assigned the realization of a complex mission involving various changing tasks.

Genetic design of 3D modular manipulators

This paper proposes a method for task based design of modular robotic systems using genetic algorithms (GA). We introduce a 3D kinematic description for modular serial manipulators and a two-level GA to optimize their topology from task specifications. Revolute and prismatic joints are considered and the number of DOF is let to the GA to determine (allowing redundant manipulators). The upper-level GA is dedicated to the topology evolution and uses the lower-level GA to search for inverse kinematics problem solutions. The topology is evolved for adaptation to a global task constituted by several required end effector configurations (subtasks). The implemented GA optimizes several performance criteria under constraints. To illustrate the method capacities, an example is presented for a redundant manipulator in a cluttered workspace.

An Active Tubular Polyarticulated Micro-System for Flexible Endoscope

This paper describes an original active steering device for endoscopes and boroscopes. Its mechanical structure is based on a tubular hyper-redundant mechanism. Distributed SMA actuators with their own local controller are integrated in this structure for producing bending forces in reaction to the interaction detected between the instrument and its environment.

Planning and controlling cooperating robots through distributed impedance

This article presents distributed impedance as a new approach for multiple robot system control. In this approach, each cooperating manipulator is controlled by an independent impedance controller. In addition, along selected degrees of freedom, force control is achieved through an external loop, to improve control of the objects internal loading. Extensive stability analysis is performed, based on a realistic model that includes robot impedance and object dynamics. Experiments are performed using two cooperating industrial robots holding an object through point contacts. Force and position control actions are suitably dispatched to achieve both internal loading control and object position control. Individual impedance parameters are specified according to the theoritical stability criterion. The performance of the system is demonstrated for transportation and contact tasks.

Voice and graphical -based interfaces for interaction with a robot dedicated to elderly and people with cognitive disorders

Human-robot interaction (HRI) takes place especially through interfaces. The design of such interfaces is a very delicate and crucial phase because it influences the robot accessibility and usability by the user. In this paper, we describe and analyze the results of 2 tests conducted so as to understand some of the optimal features that should characterize the robot voice and graphical-based user interfaces. Our test platform is an assistive robot developed for the elderly with mild cognitive impairments. Therefore, the user interfaces must be clear and simple. The ambiguities must be eliminated so as to facilitate the use of the robot and hence not to discourage the elderly population to use new technologies.

Optimal design of micro-actuators based on SMA wires

This paper proposes a design-oriented thermomechanical model of SMA wires. This model describes at a macroscopic scale the deformation of SMA wires in function of parameters governing the phase transformation (temperature and stress). This model is experimentaly validated on one of the most popular manufactured products: Flexinol wires. An optimal design process for SMA-wire based micro-actuators is described and illustrated through a basic structure.

Optimal design of high dexterity modular MIS instrument for coronary artery bypass grafting

This paper introduces an original, dextrous, active and modular minimally invasive instrument dedicated to coronary artery bypass grafting surgery. Its design is obtained by a generic evolutionary optimization process using Pareto-based multi objective genetic algorithms and including highly realist simulations and experimental models of the surgical gesture. The optimal instrument has 5 intra-body DOFs, is actuated by brush-less micro motors and is position controlled. Its optimization, mechanical design and performances are discussed.

Modeling robot-soil interaction for planetary rover motion control

In aim to optimize the control for an off-road robot and specially a robot with a crawling motion mode named peristaltical motion, it is essential to understand robot-soil interaction. We present an efficient method for simulating this interaction. This method can simulate the dynamic behavior of a 6-wheeled/3-axles Marsokhod type robot on different kinds of soils. With this simulation, we have defined the necessary conditions for using the peristaltical motion on sand or loose soil.