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This work solves the obstacle avoidance problem extending the Potential Field (PF) method for a mobile robot. The usual definition of the PF has been modified to have a field which is continuous everywhere. It is shown that the system has an attracting equilibrium at the target point, repelling equilibriums in the centers of the obstacles and saddle points on the borders. Those unstable equilibriums...
In this paper, a cascade control architecture for a brake-by-wire system suitable for motor racing applications is described. The system is composed of an electromechanical actuator, i.e., an electric motor, a transmission, a master cylinder, and a traditional hydraulic brake (pipe and caliper). Starting from a control-oriented model, a cascade control is proposed. An inner-loop controls the position;...
In this paper, two criteria for robust actuator fault reconstruction with sliding mode observation for a class of uncertain nonlinear systems are derived. It is known, even though the sliding mode technique is robust against unknown but bounded uncertainties, that the quality of fault reconstruction under real conditions is not as good as assumed in the design stage. This is often due to the fact...
With the introduction of new material (e.g., ultra-low-K inter-metal dielectrics) and package technology (e.g., laser grooving), there are new challenges on product reliability, especially on environmental stress tests related to film adhesion. To better understand the impacts of these changes on field applications, a new evaluation method, the die pull (DP) test, was proposed to assess the inter-layer...
In this paper a recursive algorithm for robustly stabilizing an uncertain gained controlled polynomial with affine linear coefficients, is presented. The finite step algorithm is constructed using the results of Hurwitz invariability and the respective results of simulated annealing tuning techniques. The algorithm is appropriately modified expanding the search horizon of previous algorithms aiming...
This paper considers the hierarchical control strategy for enhancing the captured and converted powers in heaving wave energy converters. The hierarchical control strategy consists of a higher hierarchical controller (HHC) and a lower hierarchical controller (LHC). The main role of the HHC is to provide the optimum reference for the LHC. The LHC follows the reference despite the existence of perturbations...
There is strong evidence that robustness in human and robotic grasping can be achieved through the deliberate exploitation of contact with the environment. In contrast to this, traditional grasp planners generally disregard the opportunity to interact with the environment during grasping. In this paper, we propose a novel view of grasp planning that centers on the exploitation of environmental contact...
A series elastic actuator (SEA) consists of a system with an intrinsically compliant mechanism, and introduces the possibility of external force/torque sensing and control. However, this mechanism is also known to reduce torque servo-control bandwidth and to separate link-side dynamics from actuator-side dynamics. The conventional solution to overcoming reduced actuation bandwidth and separated link...
The analysis of the conceptual spring mass model for running reveals swing-leg placement policies that generate very robust locomotion in unobserved terrain with large changes in ground height. However, while this theoretical result suggests a potential for large improvements on the robustness of running machines, it has so far not been demonstrated on a physical robot. Here we address this implementation...
This article presents the design for a Fault Detection and Isolation system applied to the actuator consisting in a hydraulic screw-down device used for automated running of rolling mill stands in the iron and steelmaking industry. The actuator is first described and specifications for the monitoring are proposed. The principles of the design are developed giving the main parameters to adjust with...
This paper presents methods to design the control loops for different device layouts of rate gyroscopes by modeling the micromachined rate gyroscope structures, where the very low damping of the system and plant parameter variations due to production tolerances and variability of the environment are considered. A robust controller to rebalance the seismic mass is designed for the detection loop using...
This paper is concerned with the use of active brake systems in order to decrease the rollover risk of heavy vehicles. Since the forward velocity of the vehicle changes in time, the combined yaw-roll dynamic model has a nonlinear structure. Selecting the forward velocity and the so-called normalized lateral load transfer at the rear side as scheduling parameters, a Linear Parameter Varying (LPV) model...
A wheel slip controller for Anti-lock Brake Systems (ABS) is designed using LQ-optimal control. The controller gain matrices are gain scheduled on the vehicle speed. A parameter dependent Lyapunov function for the nominal linear parameter varying (LPV) closed loop system is found by solving a linear matrix inequality (LMI) problem. This Lyapunov function is used to investigate robustness with respect...
An essential problem concerning friction compensation is over-compensation or under-compensation. In model-based compensation for friction, these events are due to over-estimation or under-estimation of the model parameters. While generally under estimation results in steady state errors, over estimation may produce oscillations and instability. In this paper, a simple servo-mechanism where the friction...
This paper presents an integrated methodology for feedback control of active vibration attenuation systems. The basic steps of the methodology are: open loop identification of the secondary path, design of a robust digital controller, identification in closed loop of a ”control oriented” model, redesign of the controller based on the closed loop identified model and controller reduction. The feasability...
In this paper the robustness of three model-based control strategies—internal model control (IMC) with linear models, IMC with neural network models, and feedback linearisation control—for the Archimedes Wave Swing (AWS), a device designed to produce electricity from the energy of sea waves, is assessed by checking how their performance, optimised for a neutral tide with a standard atmospheric pressure,...
This paper proposes a new approach in order to use the tunnel current as a position sensor at nanoscale. It is shown that electron tunneling commonly used in Scanning Tunneling Microscopes (STM) can be used to control the motion of a Nano Electromechanical System (NEMS) with an accuracy of 1.10−12m/√Hz, at ambient temperature, and using only one electrostatic actuator. The designed control strategy...
In this article the modeling and control design aspects of an electrostatic microactuator (EmA) with squeezed thin film damping effects are presented. The modeling analysis of the squeezed film damping effect is investigated in the case of an EmA composed by a set of two plates. The bottom plate is clamped to the ground, while the moving plate is driven by an electrically induced force which is opposed...
The control of systems that involve friction presents interesting challenges. Recent research has focused on detailed modeling of friction phenomena in order to use robust on-line friction compensation procedures, attempting to cancel out the friction force effect in the feedback control. The friction modeling problem remains a very difficult challenge. The friction effect acting in a dynamic system...
This paper addresses bilateral teleoperation of a car-like rover with communication delay. The proposed teleoperation scheme enables change of linear velocity and steering angle of the rover by pushing and pulling a haptic joystick. An environmental force determined according to relative distances and speeds between the rover and obstacles is rendered to the human operator. The human operator perceives...
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