scholarly journals Adaptive Position/Force Control of a Robotic Manipulator in Contact with a Flexible and Uncertain Environment

Robotics ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 32
Author(s):  
Piotr Gierlak
Keyword(s):  
Control Systems ◽  
Movement Control ◽  
Interaction Force ◽  
Resistance Force ◽  
Control Law ◽  
Robot Interaction ◽  
Control Laws ◽  
The Impact ◽  
Interaction Surface ◽  
Selection Of

The present paper concerns the synthesis of robot movement control systems in the cases of disturbances of natural position constraints, which are the result of surface susceptibility and inaccuracies in its description. The study contains the synthesis of control laws, in which the knowledge of parameters of the susceptible environment is not required, and which guarantee stability of the system in the case of an inaccurately described contact surface. The novelty of the presented solution is based on introducing an additional module to the control law in directions normal to the interaction surface, which allows for a fluent change of control strategy in the case of occurrence of distortions in the surface. An additional module in the control law is perceived as a virtual viscotic resistance force and resilient environment acting upon the robot. This interpretation facilitates intuitive selection of amplifications and allows for foreseeing the behavior of the system when disturbances occur. Introducing reactions of virtual constraints provides automatic adjustment of the robot interaction force with the susceptible environment, minimizing the impact of geometric inaccuracy of the environment.

Studies of the Modelling Accuracy of Steam Turbine Control Systems for Diagnostic Tests of Automatic Synchronizers

2013 ◽  
Vol 199 ◽  
pp. 61-66
Author(s):  
Grzegorz Redlarski ◽  
Janusz Piechocki ◽  
Mariusz Dąbkowski
Keyword(s):  
Angular Velocity ◽  
Control Systems ◽  
Working Conditions ◽  
Synchronous Generator ◽  
Angular Speed ◽  
Velocity Control ◽  
Reliable Operation ◽  
Relevant Field ◽  
The Impact ◽  
Selection Of

One of the important factors that affect the reliable operation of the power system and the rapid restitution after disaster is a quick and effective combining synchronous electric power facilities to operate in parallel [. Hence, diagnostics of automatic synchronizers at every stage of their life, from building a prototype, through the whole life, until removing such devices from the operation, is an extremely important and responsible activity. In ordinary practice, this action is performed by dedicated test of mechatronics systems, called simulators [2, , in close to real - or even more restricted - conditions. One of the major limitations in the relevant field undoubtedly concerns the selection of an appropriate structure and implementation of models of the angular velocity control systems involved in the process of connection. These models must be simple enough to allow computation with a frequency of kHz, and, at the same time, developed enough to be able to form diverse and close to real working conditions. For these reasons, classical approach is not possible, allowing the use of well-known Parks model [ of the synchronous generator and the complex - and often nonlinear [. Hence, considered above-mentioned requirements and indicated constraints, to test the automatic synchronizer the designers of mechatronics systems use a number of simplifications during modeling of the angular speed control systems [. However, models are not detailed enough to study the impact of changes in the shape of relevant characteristics under the influence of changes the angle of phase discrepancy in the process of connecting. Hence, this paper presents the results of the research of the currently used method of modeling the most commonly used control systems of angular velocity, in the respective systems.

scholarly journals Design of Composite Feedback and Feedforward Control Law for Aircraft Inertially Stabilized Platforms

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Valerii Azarskov ◽  
Anatoly Tunik ◽  
Olha Sushchenko
Keyword(s):  
Control Systems ◽  
Feedforward Control ◽  
Design Method ◽  
Synergetic Effect ◽  
Measurement Unit ◽  
Control Law ◽  
Control Laws ◽  
Robustness Criterion ◽  
Two Stages ◽  
Invariance Theory

The design of the control systems of the inertially stabilized platforms (ISPs) as part of airborne equipment for the majority of aircraft has its peculiarity. The presence of rate gyros in the inertial measurement unit gives the possibility to measure the rotation rate of the ISP base, which is the main disturbance interfering with the ISP accuracy. Inclusion of the feedforward disturbance gain in the control law with the simplest PI feedback significantly improves the accuracy of stabilization by the invariance theory. A combination of feedback and feedforward controllers produces a synergetic effect, thus, improving ISP accuracy. This article deals with the design of the airborne ISP control systems consisting of two stages: the parametric optimization of the PI feedback control based on composite “performance-robustness” criterion and the augmentation of the obtained system with feedforward gain. To prove the efficiency of the proposed control laws, the simulation of the ISP was undertaken. We have used a simulation of the heading-hold system of the commuter aircraft Beaver and the yaw rate output of this closed-loop system we have used as a source of the disturbance. The results of modeling proved the efficiency of the proposed design method.

Design and Modeling of Variable Stiffness Joints Based on Compliant Flexures

2010 ◽  
Author(s):  
Gianluca Palli ◽  
Claudio Melchiorri ◽  
Giovanni Berselli ◽  
Gabriele Vassura
Keyword(s):  
Compliant Mechanism ◽  
Variable Stiffness ◽  
Human Robot Interaction ◽  
Robot Interaction ◽  
Control Laws ◽  
Compliant Behavior ◽  
Stiffness Profile ◽  
And Performance ◽  
Definition Of ◽  
Selection Of

The development of safe and dependable robots for physical human-robot interaction is actually changing the way robot are designed introducing several new technological issues. Outstanding examples are the adoption of soft covers and compliant transmissions or the definition of motion control laws that allow a compliant behavior in reaction to possible collisions, while preserving accuracy and performance during the motion in the free space. In this scenario, a growing interest is devoted to the study of variable stiffness joints. With the aim of improving the compactness and the flexibility of existing mechanical solutions, a variable stiffness joint based on the use of compliant flexures is investigated. The proposed concept allows the implementation of a desired stiffness profile and range along with the selection of the maximum joint deflection. In particular, this paper reports a systematic procedure for the synthesis of a fully-compliant mechanism used as a non-linear transmission, together with a preliminary design of the overall joint.

Investigating LiDAR Sensing Errors for Wind Turbines Loads Reduction

2014 ◽  
Author(s):  
Benoit Bayon ◽  
Jonathan Chauvin
Keyword(s):  
Wind Turbines ◽  
Domain Model ◽  
Control Law ◽  
Lidar Measurement ◽  
Reliable Measurement ◽  
Error Sources ◽  
Control Laws ◽  
Pitch Control ◽  
Turbine Performance ◽  
The Impact

LiDAR sensors are a promising technology for a reliable measurement of the incoming wind. This is especially useful for applications such as antennas and wind turbines. For wind turbines, the use of this sensor provides the information of the rotor wind speed which can be used in dedicated control laws to improve the wind turbine performance, mainly on the mechanical loads and extreme moments. However the provided information is not flawless. Several error sources exist and degrade the wind information. As a consequence, the performance of the blade pitch control law is reduced. In this paper, an insight of the LiDAR measurement error sources is provided through the establishment of a frequency domain model. The impact of these errors on the performance of a blade pitch control law is investigated, along with the comparison with a standard control law.

Methods for Restricting Maximum Exposure Rate in Computerized Adaptative Testing

Methodology ◽  
2007 ◽  
Vol 3 (1) ◽  
pp. 14-23 ◽  
Author(s):  
Juan Ramon Barrada ◽  
Julio Olea ◽  
Vicente Ponsoda
Keyword(s):  
Measurement Accuracy ◽  
Computerized Adaptive Testing ◽  
Computation Time ◽  
Adaptive Testing ◽  
Exposure Rate ◽  
Control Parameters ◽  
The Impact ◽  
Two Alternatives ◽  
Selection Of ◽  
Maximum Exposure

Abstract. The Sympson-Hetter (1985) method provides a means of controlling maximum exposure rate of items in Computerized Adaptive Testing. Through a series of simulations, control parameters are set that mark the probability of administration of an item on being selected. This method presents two main problems: it requires a long computation time for calculating the parameters and the maximum exposure rate is slightly above the fixed limit. Van der Linden (2003) presented two alternatives which appear to solve both of the problems. The impact of these methods in the measurement accuracy has not been tested yet. We show how these methods over-restrict the exposure of some highly discriminating items and, thus, the accuracy is decreased. It also shown that, when the desired maximum exposure rate is near the minimum possible value, these methods offer an empirical maximum exposure rate clearly above the goal. A new method, based on the initial estimation of the probability of administration and the probability of selection of the items with the restricted method ( Revuelta & Ponsoda, 1998 ), is presented in this paper. It can be used with the Sympson-Hetter method and with the two van der Linden's methods. This option, when used with Sympson-Hetter, speeds the convergence of the control parameters without decreasing the accuracy.

Impact of removing ESBL designation from culture reports on the selection of antibiotics for the treatment of infections associated with ESBL-producing organisms

2020 ◽  
Vol 41 (5) ◽  
pp. 604-607 ◽  
Author(s):  
Mark D. Lesher ◽  
Cory M. Hale ◽  
Dona S. S. Wijetunge ◽  
Matt R. England ◽  
Debra S. Myers ◽  
...  
Keyword(s):  
Antimicrobial Stewardship ◽  
Antibiotic Prescribing ◽  
The Impact ◽  
Inhibitor Combination ◽  
Lactamase Inhibitor ◽  
Selection Of

AbstractWe characterized the impact of removal of the ESBL designation from microbiology reports on inpatient antibiotic prescribing. Definitive prescribing of carbapenems decreased from 48.4% to 16.1% (P = .01) and β-lactam–β-lactamase inhibitor combination increased from 19.4% to 61.3% (P = .002). Our findings confirm the importance of collaboration between microbiology and antimicrobial stewardship programs.

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