Permanent Magnet Synchronous Motor control via Parameter Dependent Relay Control

International audienceThe article presents a novel control strategy for the control of Permanent Magnet Synchronous Motor (PMSM). The approach is motivated by the fact that PMSM are usually controlled by relays and thus only a finite set of control inputs is available. However in classical control design the use of Pulse-Width Modulation (PWM) ignores the relay nature of the actuators. Here we propose a direct relay control. As PMSM may be modeled as Linear Parameter Varying (LPV) systems, we propose a Parameter Dependent Relay (PDR) control. A design based on Linear Matrix Inequalities (LMI) allows to derive the switching surfaces, which depend on the motor position. The theory described is illustrated by simulations results

Derivative based control for LPV system with unknown parameters: An application on a Permanent Magnet Synchronous Motors

International audienceThis paper deals with the robust stabilization of a class of Linear Parameter Varying (LPV) systems in the continuous time case. Instead of using a state observer or searching for a dynamic output feedback, the controller is based on output derivative estimation. This allows the stabilization of the plant with very large parameter variation and uncertainties. The proof of stability is based on the polytopic representation of the closed loop, Lyapunov conditions and system transformations. The result is a control structure with only few parameters which are tuned via very simple conditions. This paper illustrates the usefulness on real application: Permanent Magnet Synchronous Motors (PMSM) position control

Networked control and observation for Master-Slave systems

2009, 350 p. 110 illus., Hardcover. ISBN: 978-0-387-85594-3This chapter concerns the design of a remote control loop constituted by a Slave system (with computing and energy limitations) and a Master computer, communicating via an Internet connection. In such a situation, the communication cost is reduced but the Quality of Service of the Internet connection is not guaranteed. In particular, when the Slave dynamics are expected to be fast enough, the network induces perturbations (delays, jitters, packet dropouts and sampling) that may damage the performance. Here, the proposed solution relies on a delay-dependent, state-feedback control, computed by the Master on the basis of an observer. This last estimates the present Slave's state from its past sampled outputs, despite the various delays. Then, the computing task is concentrated in the Master. The theoretical results are based on the Lyapunov-Krasovskii functional and the approach of LMI, which guarantee the stabilization performance with respect to the expected maximum delay of the connection. Two strategies are applied: one is a constant controller/observer gain strategy, which takes into account a fixed upperbound for the communication delay. The second strategy aims at improving the performance by adapting the gains to the available network QoS (here, with two possible upperbounds)

Delay dependent stability analysis of interval time-delay systems

International audienceWe consider interval time-varying delay systems. The time-delay interval is divided into several zones and the systems switch among the different zones. Based on Lyapunov-Krasovskii functional methods and on linear matrix inequality (LMI) techniques, exponential stability is exploited for every time-delay zone. The global stability of the switched system is guaranteed if some minimum average dwell time conditions are satisfied. Numerical examples and comparisons with other works show that the methods enlarge the value of the maximum upper-bound of allowable time-delays

A gain scheduling strategy for the control and estimation of a remote robot via Internet

International audienceA gain scheduling strategy for the controller of a remote robot based on Internet and Bluetooth networks is designed and implemented. The Internet communication is based on the Master-Slave structure, UDP protocol. The Slave comprises a PC and a mobile robot, interconnected through the protocol Bluetooth. The Master is a second PC which realizes the remote control, the design of which is based on a remote observer achieving a state prediction of the robot (Slave), despite the variable communication delays, sampling and packets losses. The detected variable time delays serve as the switching signals. The gain scheduling state feedback controller is based on Lyapunov-Krasovskii functional and the approach of LMI, which guarantee the uniform stabilization performance

Output control with Internet-in-the-loop : An event-driven realization

International audienceThis work is devoted to the remote feedback control of a linear process with "Internet in the loop". In such a networked control situation, variable and unpredictable delays arise, which may decrease the global performance or destabilize the system. Our aim is to obtain the best performance despite the variation of the network QoS (quality of service). The considered application is based on a Master-Slave structure. The Slave is a light mobile robot, that receives the control data and sends its sampled position via a UDP protocol. A Master computer realizes the remote control, based on a remote observer and a state feedback. The global strategy is without buffers. The packets are time-stamped so the Master detects the variable time delays (the network QoS). This information is used to adapt its observer/controller gains and guarantee the best possible performances. The design of this gain scheduling strategy relies on Lyapunov-Krasovskii functionals with an LMI optimization which guarantees the stability even with packet losses. Experimental results are provided

Discrete and intersample analysis of systems with aperiodic sampling

International audienceThis article addresses the stability analysis of linear time invariant systems with aperiodic sampled-data control. Adopting a difference inclusion formalism, we show that necessary and sufficient stability conditions are given by the existence of discrete-time quasi-quadratic Lyapunov functions. A constructive method for computing such functions is provided from the approximation of the necessary and sufficient conditions. In practice, this leads to sufficient stability criteria under LMI form. The inter-sampling behavior is discussed there: based on differential inclusions, we provide continuous-time methods that use the advantages of the discrete-time approach. The results are illustrated by numerical examples that indicate the improvement with regard to the existing literature

FEM-Based Exterior Workspace Boundary Estimation for Soft Robots via Optimization

International audienceThis paper investigates the exterior workspace boundary of a soft robot with a certain configuration controlled by equipped bounded actuators. To achieve this, we implement an optimization-based approach on the studied soft robot which has been modeled by the Finite Element Method (FEM). Finally, we provide numerical simulations of various configurations to demonstrate the validity of the suggested technique, which, in comparison to the conventional forward method, may considerably minimize the complexity of exterior workspace boundary estimation

FEM-based Reachable Workspace Estimation of Soft Robots using an Interval Analysis approach

International audienceConsidering a soft robot with installed bounded actuators, this paper studies the reachable workspace estimation problem for a pre-chosen point of interest. To this aim, the method of nite-element has been used to obtain the static model of the studied robot and two methods are proposed (forward one which is based on Newton iterative method and forward-backward one which is based on interval analysis techniques) to study this estimation problem. Various simulations with dierent conguration scenarios are provided to show the eectiveness of the forward-backward approach which can largely reduce the exploration time, compared to the forward method

H∞H_{\infty} Control of Delayed Teleoperation Systems under Polytopic-Type Uncertainties

International audienceIn this paper, the $H_{\infty}$ control design under time-varying delays and polytopic-type uncertainties, which ensures the stability and performance (synchronization/transparency) between the master and slave manipulators, is proposed. With this objective, the design of the controller based on our proposed control scheme is performed by using Linear Matrix Inequality (LMI) optimization based on Lyapunov-Krasovskii functionals (LKF) and $H_{\infty}$ control theory. The solution is efficient for different working conditions, \emph{e.g.} abrupt tracking and wall contact motion, and this is illustrated by a final example