KERMORGANT , Olivier

This thesis deals with sensor-based control of robots. For a robot arm or a mobile robot, this approach consists in defining robotic tasks directly in the sensor space. This scheme is known for its good properties of accuracy and stability. The robot may still have an undesired behavior when the motion to perform is large or when constraints...

Joint limits avoidance is a crucial issue in sensor- based control. In this paper we propose an avoidance strategy based on a low-level data fusion. The joint positions of a robot arm are considered as features that are continuously added to the control scheme when they approach the joint limits, and removed when the position is safe. We expose...

In this paper we address the issue of hybrid 2D/3D visual servoing. Contrary to popular approaches, we consider the position-based visual servo as the core of our scheme. 2D information is only added when necessary, that is when the observed object is about to leave from the field of view, even partially. The injection of 2D information is...

A low-level sensor fusion scheme is presented for the positioning of a multi-sensor robot. This non-hierarchical framework can be used for robot arms or other velocity- controlled robots, and is part of the task function approach. A stability analysis is presented for the general case, then several control laws illustrate the versatility of the...

A framework is presented in this paper for the control of a multi-sensor robot under several constraints. In this approach, the features coming from several sensors are treated as a single feature vector. The core of our approach is a weighting matrix that balances the contribution of each feature, allowing to take constraints into account. The...

Visual Servoing has been widely investigated inthe last decades as it provides a powerful strategy for robotcontrol. Thanks to the direct feed-back from a set of sensors,it allows to reduce the impact of some modeling errors and toperform tasks even in uncertain environments. The commonlyexploited approach in this...

In this paper we propose a new on-line sensor self-calibration framework. The approach is to consider the sensor/robot interaction that links the sensor signal variations to the robot velocity. By on-line calibration, we mean only the actual measurements are used to perform calibration under the condition that the interaction matrix is...

This paper presents a multi-task control method to maintain the visibility of an anatomic element of interest while the doctor tele-operates a 2D ultrasound probe held by a medical robot. The prior task consists in automatically maintaining several visual constraints that guarantee an inter-section between the ultrasound image plane and the...

Sampling-based planning algorithms have been extensively exploited to solve a wide variety of problems. In recent years, many efforts have been dedicated to extend these tools to solve problems involving constraints, such as geometric loop-closure, which lead the valid Configuration Space (CS) to collapse to a lower-dimensional manifold. One...

Many robotics tasks involve a set of constraints that limit the valid configurations the system can assume. Some of these constraints, such as loop-closure or orientation constraints to name some, can be described by a set of implicit functions which cause the valid Configuration Space of the robot to collapse to a lower-dimensional manifold....

This paper proposes new prediction models for Visual Predictive Control that can lead to both better motions in the feature space and shorter sensor trajectories in 3D. Contrarily to existing first-order models based only on the interaction matrix, it is proposed to integrate acceleration information provided by second-order models. This allows...

This paper proposes new prediction models for Visual Predictive Control that can lead to both better motions in the feature space and shorter sensor trajectories in 3D. Contrarily to existing first-order models based only on the interaction matrix, it is proposed to integrate acceleration information provided by second-order models. This allows...

This paper proposes a longitudinal control framework for platooning in an urban environment. The targetted application is to redistribute vehicles involved in car-sharing systems, where only the leader vehicle is human-driven. We propose a platoon model and control law considering actuator dynamics. This control relies on a hybrid Information...

In this paper, a distributed observer-based approach is proposed to control the longitudinal motion of car-like vehicle platoon moving in an urban environment. To the best of our knowledge, this is the first work presenting an observer-based platoon controller that combines the advantages of high traffic capacity and a minimum number of...

This paper proposes a distributed longitudinal controller for car-like vehicles platooning that travel in an urban environment. The presented control strategy combines the platoon maintaining, gap closure, and collision avoidance functionality into a unified control law. A consensus-based controller designed in the path coordinates is the basis...

Solving Direct Shooting Model Predictive Control (MPC) optimization problems online can be computationally expensive if a large horizon is used while also maintaining a dense time sampling. In these cases, it is accepted that tradeoffs between computational load and performances should be sought in order to meet real-time feasibility...

In this research, a general control framework for platooning in urban environment is proposed. A consensus-based control law is described taking into account the nature of traveling in urban environment, that is the human driven leader travels with variable velocity. In addition, the proposed control law does not depend on the predecessor...

Model Predictive Control (MPC) while being a very effective control technique can become computationally demanding when a large prediction horizon is selected. To make the problem more tractable, one technique that has been proposed in the literature makes use of control input parameterizations to decrease the numerical complexity of nonlinear...

In this paper, we study longitudinal motion controlof car-like vehicles platoon navigating in an urban environmentwith minimum communication links. To achieve a higher trafficflow, a constant-spacing policy between successive vehicles iscommonly used but this is at a cost of an increased number ofcommunication links as any vehicle...

This paper explores the feasibility of a Multi-Sensor-Based Predictive Control (MSBPC) approach for addressing backward nonparallel (perpendicular and diagonal) parking problems of car-like vehicles as an alternative to more classical (e.g. path planning based) approaches. The results of a few individual cases are presented to illustrate the...

This paper addresses the perpendicular and parallel parking problems of car-like vehicles for both forward and reverse maneuvers in one trial by extending the work presented in [1] using a multi sensor based controller with a weighted control scheme. The perception problem is discussed briefly considering a Velodyne VLP-16 and a SICK LMS151 as...

This paper formalizes, under a single common Multi-Sensor-Based Predictive Control framework, five different types of parking maneuvers: perpendicular, diagonal for both forward and backward motions and parallel for backward motions. Since, from a practical point of view, forward parallel parking is usually not advisable, it is not addressed in...

We present an experimental study for the generation of large 3D maps using our CoMapping framework. This framework considers a collaborative approach to efficiently manage, share, and merge maps between vehicles. The main objective of this work is to perform a cooperative mapping for urban and rural environments denied of continuous-GPS...

CoMapping is a framework to efficient manage, share, and merge 3D map data between mobile robots. The main objective of this framework is to implement a Collaborative Mapping for outdoor environments. The framework structure is based on two stages. During the first one, the Pre-Local Mapping stage, each robot constructs a real time pre-local...