G. Ducard

G. Ducard

Ph.D. ETH Zürich

About

60
Publications
16,227
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,239
Citations
Additional affiliations
January 2010 - June 2020
University of Nice Sophia Antipolis
Position
  • Professor (Associate)
November 2007 - December 2009
ETH Zurich
Position
  • Post Doc Position
Description
  • Setting up the Flying Machine Arena Project
November 2004 - November 2007
ETH Zurich
Position
  • PhD

Publications

Publications (60)
Article
Full-text available
RTOB-SLAM is a new low-computation framework for real-time onboard simultaneous localization and mapping (SLAM) and obstacle avoidance for autonomous vehicles. A low-resolution 2D laser scanner is used and a small form-factor computer perform all computations onboard. The SLAM process is based on laser scan matching with the iterative closest point...
Article
Hybrid unmanned aerial vehicles (UAVs) provide an interesting combination of the vertical takeoff and landing (VTOL) capabilities of rotary-wing (RW) and of the efficient forward flight of fixed-wing (FW) vehicles. The employed controllers must be able to handle the highly nonlinear dynamics and changing control authorities resulting from this comb...
Article
This paper provides a broad perspective and analysis of the work done in control of hybrid and convertible unmanned aerial vehicles (UAVs) for the main existing designs. These flying machines are capable of vertical take off and landing (VTOL) in helicopter mode and able to transition to high-speed forward flight in airplane mode and vice versa. Th...
Article
This article presents a model predictive control (MPC) controller and its novel application to a hybrid tilt-quadrotor fixed-wing aircraft, which combines vertical takeoff and landing (VTOL) capabilities with high-speed forward flight. The developed MPC controller takes a velocity command from the pilot and then computes optimal attitude setpoints...
Article
A major issue in active fault-tolerant control (FTC) is having to rely on uncertain information provided by the fault detection and identification (FDI) algorithm. To achieve a reliable FTC, the controller needs to be robust against FDI uncertainties, namely missed “small” faults and fault detection delays. In this article, the FDI system only need...
Article
This paper proposes a fault-tolerant control (FTC) approach for unknown actuator faults based on robust control theory. The µ-analysis is used to infer closed-loop stability against different actuator faults. Further, an adapted DK-iteration approach is used to compute a guaranteed robustly stable FTC, given an actuator redundant system. The perfor...
Article
Full-text available
A robust and reliable attitude estimator is a key technology enabler for the development of autonomous aerial vehicles. This paper is an introduction to attitude estimation for aerial robotic systems. First, attitude definition and parameterizations are recalled and discussed. Then, several attitude estimation techniques – ranging from algebraic ve...
Conference Paper
In this paper, the mathematical modeling of a hybrid aerial vehicle is presented. This vehicle is a combination of a fixed-wing aircraft and a multirotor helicopter. This vehicle is thus capable of vertical take off and landing (VTOL) and of cruising forward flight. The thrust is generated by 4 propellers which can pivot and thus the direction of t...
Conference Paper
This paper presents a way to determine a weight feasibility criterion for solar-powered airplanes designed to perform infinite flight. The criterion is fast and simple to compute and can be used for initial assessments on aircraft design and mission planning. The derivation starts with taking solar cell weight and efficiency into account, then is e...
Conference Paper
This paper introduces a novel, robust and efficient approach for metric velocity estimation using multiple cameras with no overlapping fields of view. By incorporating rotation priors, the metric velocity estimation problem reduces to solving a set of linear equations. To determine the metric velocity, a total of three temporal point correspondence...
Conference Paper
This paper presents a new scheme for sensor fault detection and isolation. It uses a single Kalman filter and a Gaussian hidden Markov model for each of the monitored sensors. This combination is able to simultaneously detect single and multiple sensor faults, still guaranteeing optimal system state estimation. This algorithm also can run on system...
Chapter
Future unmanned aerial vehicles (UAVs) will be designed to achieve their missions with increased efficiency, safety, and security. To this end, an efficient fault detection and isolation (FDI) system should be capable of monitoring the health status of the aircraft. Fault-tolerant control systems for small and low-cost UAVs should not increase sign...
Book
Future unmanned aerial vehicles (UAVs) will be designed toachieve their missions with increased efficiency, safety, andsecurity. To this end, an efficient fault detection and isolation(FDI) system should be capable of monitoring the health statusof the aircraft. Fault-tolerant control systems for small andlow-cost UAVs should not increase significa...
Article
Full-text available
This chapter presents an intuitive laser-based teleoperation scheme to enable the safe operation of a multirotor UAV by an untrained user in a cluttered environment using a haptic joystick. An obstacle avoidance strategy is designed and implemented to autonomously modify the position setpoint of the UAV if necessary. This scheme includes a novel fo...
Conference Paper
This paper provides a review of different possible strategies to compute meaningful states of an unmanned aerial vehicle (UAV) in the presence of sensor faults. The paper reviews some strategies that enable to compute useful outputs and to reconstruct sensor data when some sensor(s) become(s) deficient. In addition to a classical sensor suite for U...
Conference Paper
Full-text available
This paper presents the design and evaluation of a nonlinear flight control system for multi-rotor helicopters by taking into account first-order drag effects such as blade flapping and induced drag. A dynamic model of a multirotor vehicle is derived, with both blade flapping- and induced drag dynamics included. Using this model, it is shown that t...
Conference Paper
This paper presents extensions made to the Single Model Active Fault Detection and Isolation System (SMACFDI) presented previously by the author. The SMAC-FDI system is designed to efficiently detect and isolate a faulty actuator in a system, such as a small aircraft. The implementation of the filter, which generates state residuals has been revisi...
Conference Paper
This paper introduces a state estimation framework that allows estimating the attitude, full metric speed and the orthogonal metric distance of an IMU-camera system with respect to a plane. The filter relies only on a single optical flow feature as well as gyroscope and accelerometer measurements. The underlying assumption is that the observed visu...
Conference Paper
This paper introduces a state estimation framework that allows estimating the attitude, full metric speed and the orthogonal metric distance of an IMU-camera system with respect to a plane. The filter relies only on a single optical flow feature as well as gyroscope and accelerometer measurements. The underlying assumption is that the observed visu...
Conference Paper
Full-text available
This paper presents an intuitive teleoperation scheme to safely operate a wide range of VTOL UAVs by an untrained user in a cluttered environment. This scheme includes a novel force-feedback algorithm that enables the user to feel the texture of the environment. In addition, a novel mapping function is introduced to teleoperate the UAV in an unlimi...
Conference Paper
Full-text available
This paper addresses the issue of flight safety and reliability of unmanned multirotor helicopters. New applications involve the use of such flying platforms to perform inspection of industrial facilities, bridges, dam walls, etc. In this context, the multirotor helicopter is teleoperated by a distant human user. The capability of fault-tolerance a...
Conference Paper
Full-text available
In this paper, a novel nonlinear hierarchical controller for attitude control is proposed. This controller is obtained using Lyapunov methodology. Model uncertainties in the system are estimated on-line based on a time-delay control approach. The robustness of the ight controller is enhanced using an anti-windup integrator technique and semi-globa...
Conference Paper
Full-text available
Any low-cost IMU is subject to biased measurement in its gyroscopes. This paper presents a nonlinear attitude observer which incorporates anti-windup gyro-bias compensation. It also provides an extension of the decoupling strategy of IMU measurement recently proposed in the literature by providing almost global stability proof along with a comprehe...
Conference Paper
Full-text available
This paper presents a new scheme for actuator fault detection and isolation (FDI) with application to actuator health monitoring on an aircraft. The Single Model Active Fault Detection and Isolation System (SMAC-FDI) efficiently detects and isolates a faulty actuator in a system. This method has a short response time and is robust against model unc...
Conference Paper
Full-text available
In this project, a Vicon motion capture/positioning system is employed to provide the pose (ground position, ground velocity and attitude) of an autonomous quadrotor. Some markers are mounted on the vehicle so that the Vicon system can track it. The markers arrangement is stored once in the Vicon system. In practice, after a few flights the markers...
Book
Unmanned aerial vehicles (UAVs) offer an incomparable means of gathering intelligence and carrying out missions without needing an onboard human pilot. The benefits are considerable in terms of cost, efficiency, and reduced pilot risk. In order to complete a mission efficiently and with a high level of safety and security, the following key design...
Chapter
In this chapter, three main limitations of the classical implementation of the MMAE method to isolate faults based on predefined fault hypotheses are highlighted. The first limitation concerns the number of filters that must be designed in order to span the range of possible fault scenarios, which must be limited due to computational load. The seco...
Chapter
The FDI system developed in this book runs n (number of actuators) + 1 EKFs in parallel. Current and future research work of the author focuses on a technique to reduce the computational complexity needed to achieve fault diagnoses with at least the same level of reliability and performance.
Chapter
After an actuator failure, the performance of the aircraft is degraded. If an FDI system is available in the flight control system, the knowledge of the failure can be used to evaluate the new aircraft performance. Based thereon, a supervision system decides whether the mission can still be continued or if it should be aborted and have the aircraft...
Chapter
This chapter is dedicated to the analysis and control of the lateral motion of the aircraft and presents an architecture for the lateral-directional controllers which use robust NDI in all of the control loops. This chapter brings an innovative and practical approach for stability and robustness analyses of the plant undergoing the dynamic inversio...
Chapter
An aircraft is intrinsically a nonlinear system. Therefore, if linear controllers are to be used in the aircraft flight control system, several linear controllers have to be designed and then gain-scheduled over the operating regime of the aircraft. However, recent nonlinear control techniques have made it possible to deal directly with the known n...
Chapter
The nonlinear differential equations governing the motion of an aircraft are described in Chap. 3. For the plant analysis and control design, these equations are linearized around a certain operating point. Two sets of state variables appear to be clearly decoupled, each defining a specific mode of aircraft motion. The state variables involved in t...
Chapter
This chapter describes the design of a control allocation module with explicit laws for fast operation and low computational load, such that this algorithm can run in a small processor or microcontroller with limited floating-point operation capability. The control allocation method is capable of compensating for actuator faults. Given the appropri...
Chapter
This chapter presents a guidance algorithm for a UAV. It combines a nonlinear lateral guidance control law, originally designed for UAVs tracking circles for mid-air rendezvous, with a new simple adaptive path-planning algorithm. Preflight path planning consists only of storing a few waypoints guiding the aircraft to its targets. The chapter presen...
Chapter
This chapter presents the axes, the frames, and the nonlinear model of the aircraft used in this book [1–4].
Conference Paper
Full-text available
Nonlinear dynamic inversion (NDI) is a very popular method employed in aircraft automatic flight control systems. However, it is known that this technique may have stability and robustness issues as soon as the model parameters used in the inversion process are uncertain or when the measurement data are noisy and biased. Many advanced analysis tech...
Conference Paper
Full-text available
This paper presents a nonlinear airspeed controller for an unmanned aerial vehicle (UAV). It is designed using the technique of nonlinear dynamic inversion. The thrust force of the UAV is generated by a propeller. The nonlinear dynamics of the airspeed are appropriately expressed as a function of the thrust force, which is a nonlinear function of t...
Article
Full-text available
In this paper, three main limitations of the classical implementation of the multiple-model adaptive-estimation method to isolate faults based on predefined fault hypotheses are highlighted. The first concerns the number of filters that must be designed to span the range of possible fault scenarios, which must be limited due to computational load....
Conference Paper
Full-text available
This paper presents a guidance algorithm for an unmanned aerial vehicle (UAV). It combines a nonlinear lateral guidance control law, originally designed for UAVs tracking circles for mid-air rendezvous, with a new simple adaptive path planning algorithm. Preflight path planning only consists of storing a few way points guiding the aircraft to its t...
Conference Paper
Full-text available
In this paper, a computationally efficient guidance algorithm has been designed for a small aerial vehicle. Preflight path planning only consists of storing a few waypoints guiding the aircraft to its target. The paper presents an efficient way to model no-fly zones and to generate a path in real-time in order to avoid the obstacles, even in the ev...
Conference Paper
Full-text available
In this paper, a control allocation module with explicit laws has been designed for fast operation and low computational load, so that this algorithm can run in a small processor or microcontroller with limited floating point operation capability. The control allocation method is capable of compensating for actuator faults. Given the appropriate fa...
Conference Paper
Full-text available
The ability of the multiple model adaptive estimation method (MMAE) to detect faults based on a predefined hypothesis and the parameter-estimating ability of an extended Kalman filter (EKF) results in an efficient fault detection approach. This extended multiple model adaptive estimation method (EMMAE) has been investigated on a nonlinear model of...
Conference Paper
Full-text available
A combination of the multiple model adaptive estimation method (MMAE) with an extended Kalman filter (EKF) is considered. The ability of the MMAE method to detect faults based on a predefined hypothesis and the parameter-estimating ability of an EKF results in a very efficient fault detection approach. This so-called extended multiple model adaptiv...

Network

Cited By