scholarly journals The Modeling of Redundantly Actuated Mechanical Systems

2019 ◽  
Vol 11 (6) ◽  
Author(s):  
Yaojun Wang ◽  
Bruno Belzile ◽  
Jorge Angeles ◽  
Qinchuan Li
Keyword(s):  
Degrees Of Freedom ◽  
Screw Theory ◽  
Mechanical Systems ◽  
Coefficient Matrix ◽  
Dynamics Modeling ◽  
Norm Minimization ◽  
Redundantly Actuated ◽  
The Right ◽  
And Control

Abstract Dynamics modeling is essential in the design and control of mechanical systems, the focus of the paper being redundantly actuated systems, which bring about special challenges. The authors resort to the natural orthogonal complement (NOC), based on an adaptation of screw theory, to derive the dynamics model. Benefiting from the elimination of the constraint wrenches, the NOC offers a simple, systematic alternative to the modeling of redundantly actuated mechanical systems. The optimum actuator-torque distribution is determined via Euclidean-norm minimization; then, by relying on the QR-decomposition, an efficient and robust method is produced to compute explicitly the right Moore–Penrose generalized inverse of the coefficient matrix. The methodology is illustrated via a case study involving a redundantly actuated parallel-kinematics machine with three degrees of freedom and four actuators.

Piezothermoelasticity and Control of Piezoelectric Laminates Exposed to a Steady-State Temperature Field

1993 ◽  
Author(s):  
H. S. Tzou ◽  
R. Ye
Keyword(s):  
Temperature Field ◽  
Steady State ◽  
Degrees Of Freedom ◽  
Sensors And Actuators ◽  
System Equation ◽  
Thermal Fields ◽  
Steady State Temperature ◽  
And Control ◽  
Internal Degrees Of Freedom

Abstract Piezothermoelastic effects of distributed piezoelectric sensors and actuators are investigated. Vibration control of piezoelectric laminates subjected to a steady-state temperature field is studied. A new 3-D piezothermoelastic finite element with three internal degrees of freedom is formulated using a variational formulation. A system equation for the piezoelectric continuum exposed to combined elastic, electric, and thermal fields is formulated. Distributed sensing and control equations are derived. All these effects are studied in a case study.

A 2(3-RRPS) parallel manipulator inspired by Gough–Stewart platform

Robotica ◽  
2012 ◽  
Vol 31 (3) ◽  
pp. 381-388 ◽  
Author(s):  
Jaime Gallardo-Alvarado ◽  
Mario A. García-Murillo ◽  
Eduardo Castillo-Castaneda
Keyword(s):  
Parallel Manipulator ◽  
Degrees Of Freedom ◽  
Screw Theory ◽  
Parallel Manipulators ◽  
Forward Kinematics ◽  
Triangular Prism ◽  
Input Output ◽  
Six Degrees Of Freedom ◽  
Moving Platform

SUMMARYThis study addresses the kinematics of a six-degrees-of-freedom parallel manipulator whose moving platform is a regular triangular prism. The moving and fixed platforms are connected to each other by means of two identical parallel manipulators. Simple forward kinematics and reduced singular regions are the main benefits offered by the proposed parallel manipulator. The Input–Output equations of velocity and acceleration are systematically obtained by resorting to reciprocal-screw theory. A case study, which is verified with the aid of commercially available software, is included with the purpose to exemplify the application of the method of kinematic analysis.

scholarly journals Mitigating the transmission of infection and death due to SARS-CoV-2 through non-pharmaceutical interventions and repurposing drugs

2020 ◽  
Author(s):  
Chittaranjan Mondal ◽  
Debadatta Adak ◽  
Abhijit Majumder ◽  
Nandadulal Bairagi
Keyword(s):  
Reproduction Number ◽  
Control Strategies ◽  
Intervention Strategies ◽  
Personal Hygiene ◽  
Virus Spread ◽  
Combined Use ◽  
The Right ◽  
And Control ◽  
Pharmaceutical Interventions

The Covid-19 pandemic has put the world under immeasurable stress. There is no specific drug or vaccine that can cure the infection or protect people from the infection of coronavirus. It is therefore prudent to use the existing resources and control strategies in an optimal way to contain the virus spread and provide the best possible treatments to the infected individuals. Use of the repurposing drugs along with the non-pharmaceutical intervention strategies may be the right way for fighting against the ongoing pandemic. It is the objective of this work to demonstrate through mathematical modelling and analysis how and to what extent such control strategies can improve the overall Covid-19 epidemic burden. The criteria for disease elimination & persistence were established through the basic reproduction number. A case study with the Indian Covid-19 epidemic data is presented to visualize and illustrate the effects of lockdown, maintaining personal hygiene & safe distancing, and repurposing drugs. It is shown that India can significantly improve the overall Covid-19 epidemic burden through the combined use of NPIs and repurposing drugs though containment of spreading is difficult without serious community participation.

Active Suspension Control via Redundant Actuation

2004 ◽  
Author(s):  
Robert A. Freeman
Keyword(s):  
Degrees Of Freedom ◽  
Frontal Plane ◽  
Redundant Actuation ◽  
Suspension Systems ◽  
Stiffness Model ◽  
Suspension Control ◽  
Redundantly Actuated ◽  
Automotive Suspension ◽  
Suspension Model ◽  
And Control

The use of redundant actuation in the design and control of active automotive suspension systems is described. Redundantly actuated systems consist of more active force / torque inputs than degrees-of-freedom and allow for active control of the effective stiffness of the system to the environment without a change in the equilibrium position. A frontal plane half-car, double A-arm, independent suspension model is investigated. Results show that five actuators, with one connecting the two suspensions, is required for full stiffness and motion control. Due to the dependence of this approach on correct stiffness modeling a previously developed stiffness model is reviewed. The validity of this model is illustrated through some simple yet sufficient examples.

scholarly journals Dynamics Modeling and Control of a Quadrotor with Swing Load

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
S. Sadr ◽  
S. Ali A. Moosavian ◽  
P. Zarafshan
Keyword(s):  
Control Strategy ◽  
Control Algorithm ◽  
Degrees Of Freedom ◽  
Suspended Load ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Constant Length ◽  
Modeling And Control ◽  
Aerial Robots ◽  
And Control

Nowadays, aerial robots or Unmanned Aerial Vehicles (UAV) have many applications in civilian and military fields. For example, of these applications is aerial monitoring, picking loads and moving them by different grippers. In this research, a quadrotor with a cable-suspended load with eight degrees of freedom is considered. The purpose is to control the position and attitude of the quadrotor on a desired trajectory in order to move the considered load with constant length of cable. So, the purpose of this research is proposing and designing an antiswing control algorithm for the suspended load. To this end, control and stabilization of the quadrotor are necessary for designing the antiswing controller. Furthermore, this paper is divided into two parts. In the first part, dynamics model is developed using Newton-Euler formulation, and obtained equations are verified in comparison with Lagrange approach. Consequently, a nonlinear control strategy based on dynamic model is used in order to control the position and attitude of the quadrotor. The performance of this proposed controller is evaluated by nonlinear simulations and, finally, the results demonstrate the effectiveness of the control strategy for the quadrotor with suspended load in various maneuvers.

On the Right Parameterization of 3D Models - Case Study

2014 ◽  
Vol 657 ◽  
pp. 715-719
Author(s):  
Ionuţ Lambrescu ◽  
Ion Pană
Keyword(s):  
Degrees Of Freedom ◽  
3D Models ◽  
Point Of View ◽  
Geometric Constraints ◽  
Teaching Process ◽  
E Learning ◽  
On Line ◽  
The Right ◽  
Independent Parameters

All students in mechanical engineering courses receive training in using at least one parametric and associative 3D modeler. From the point of view of the logic behind the geometric design, a very important issue is how to parameterize the model, or put in other words, how to achieve the right balance between dimensions, as independent parameters, formulas (linking dimensions) and geometric constraints (parallel, concentric, horizontal etc.). We arrive following this logic to the notion of degrees of freedom of the model, as expressing the number of dimensions still free for a dynamic edit. The papers aim is to provide a case study capable to assist students in understanding how a good model could be built. The case study will be integrated in an on-line course, offered by our university as an expression of its commitment in developing e-learning applications [.The paper proposes a slightly different approach, compared with the ones presented in [2, 3, . While in the mentioned sources a graph approach is considered, our paper proposes a matrix oriented analysis, coupled with a live analysis of the model behavior. The paper also proposes different other models as good examples to be used in the teaching process.

Structural synthesis of a class of 3-DOF wrist mechanisms with redundantly-actuated closed-loop units

2015 ◽  
Vol 230 (2) ◽  
pp. 276-290 ◽  
Author(s):  
Haibo Qu ◽  
Yuefa Fang ◽  
Sheng Guo
Keyword(s):  
Degrees Of Freedom ◽  
Closed Loop ◽  
Screw Theory ◽  
Open Loop ◽  
Structural Synthesis ◽  
Constraint System ◽  
Redundantly Actuated ◽  
Rotational Degrees Of Freedom ◽  
Moving Platform

In this paper, a new method is proposed for the structural synthesis of a class of redundantly-actuated parallel wrists (RaPWs) with three rotational degrees of freedom of the moving platform and symmetrical structures based on screw theory. First, the new procedure for structural synthesis of RaPWs with closed-loop actuated unit is proposed and the constraint system of the moving platform of RaPWs is analyzed. Then, considering the inclusion relation between the primary constraint system and the limb constraint system, the type of kinematic limb is determined. The synthesis of type-1 and type-2 kinematic limbs is dealt with based on the obtained closed-loop actuated unit and open-loop sub-limb. Next, the RaPWs are synthesized and a number of new RaPWs have been identified. Finally, the condition for proper actuator selections of RaPWs is revealed, and one example is used to perform the validation.

Development of a Special Inertial Measurement Unit for UAV Applications

2012 ◽  
Vol 135 (1) ◽  
Author(s):  
Khaled S. Hatamleh ◽  
Ou Ma ◽  
Angel Flores-Abad ◽  
Pu Xie
Keyword(s):  
Degrees Of Freedom ◽  
Measurement Unit ◽  
Dynamics Modeling ◽  
Dynamics Model ◽  
Inertial Measurement ◽  
Six Degrees Of Freedom ◽  
On Line ◽  
Measurement Units ◽  
Sensor Models ◽  
And Control

Dynamics modeling is becoming more and more important in the development and control of unmanned aerial vehicles (UAV). An accurate model of a vehicle requires good knowledge of the dynamics properties and motion states, which are usually estimated with the help of integrated inertial measurement units (IMUs). This work develops a special six degrees of freedom IMU, which has the capability of measuring the angular accelerations. This paper introduces the design of the new IMU along with its sensor models and calibration procedures. The work introduces two experimental methods to verify the calibrated IMU readings. The IMU was designed to support an on-line methodology to estimate the parameters of UAV’s dynamics model that is currently being developed by the authors.

scholarly journals MATLAB-based Tools for Modelling and Control of Underactuated Mechanical Systems

2020 ◽  
Vol 6 (3) ◽  
Author(s):  
Slávka Jadlovská ◽  
Lukáš Koska ◽  
Matej Kentoš
Keyword(s):  
Degrees Of Freedom ◽  
Mechanical Systems ◽  
Underactuated Systems ◽  
Underactuated Mechanical Systems ◽  
Software Support ◽  
Nonlinear Mechanical ◽  
Inertia Wheel Pendulum ◽  
Nonlinear Mechanical Systems ◽  
And Control ◽  
Insight Into

Underactuated systems, defined as nonlinear mechanical systems with fewer control inputs than degrees of freedom, appear in a broad range of applications including robotics, aerospace, marine and locomotive systems. Studying the complex low-order nonlinear dynamics of appropriate benchmark underactuated systems often enables us to gain insight into the principles of modelling and control of advanced, higher-order underactuated systems. Such benchmarks include the Acrobot, Pendubot and the reaction (inertia) wheel pendulum. The aim of this paper is to introduce novel MATLAB-based tools which were developed to provide complex software support for modelling and control of these three benchmark systems. The presented tools include a Simulink block library, a set of demo simulation schemes and several innovative functions for mathematical and simulation model generation.

Social Power and the Urbanization of Water

2004 ◽  
Author(s):  
Erik Swyngedouw
Keyword(s):  
Potable Water ◽  
Social Power ◽  
Right To The City ◽  
Easy Access ◽  
Social Struggle ◽  
Metabolic Transformation ◽  
The Right ◽  
And Control ◽  
The City

Taking as his case-study the city of Guayaquil in Ecuador, where 600,000 people lack easy access to potable water, Erik Swyngedouw aims to reconstruct, theoretically and empirically, the political, social, and economic conduits through which water flows, and to identify how power relations infuse the metabolic transformation of water as it becomes urban. These flows of water which are simultaneously physical and social carry in their currents the embodiment of myriad social struggles and conflicts. The excavation of these flows narrates stories about the city's structure and development. Yet these flows also carry the potential for an improved, more just, and more equitable right to the city and its water. The flows of power that are captured by urban water circulation also suggest that the question of urban sustainability is not just about achieving sound ecological and environmental conditions, but first and foremost about a social struggle for access and control; a struggle not just for the right to water, but for the right to the city itself.

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