Amirkabir University of Technology
AUT Journal of Modeling and Simulation
2588-2953
2588-2961
41
1
2009
04
01
An Adaptive-Robust Control Approach for Trajectory Tracking of two 5 DOF Cooperating Robot Manipulators Moving a Rigid Payload
1
9
EN
M.
Azadii
M.
Eghtesadii
10.22060/miscj.2009.214
In this paper, a dual system consisting of two 5 DOF (RRRRR) robot manipulators is considered as a cooperative robotic system used to manipulate a rigid payload on a desired trajectory between two desired initial and end positions/orientations. The forward and inverse kinematic problems are first solved for the dual arm system. Then, dynamics of the system and the relations between forces/moments acting on the object by the robots, using different Jacobian matrices, are derived. The proposed control method is a position control approach; therefore, it does not need the complexity of measurement of forces and moments at the contact points. Simulation results are provided to illustrate the performance of the control algorithm. The robustness of the proposed control scheme is verified in the presence of disturbance and uncertainty.
Cooperative Robots –Adaptive-Robust Control Scheme –5 DOF robot manipulators– Trajectory Tracking
http://miscj.aut.ac.ir/article_214.html
http://miscj.aut.ac.ir/article_214_a076bc1e1ec745ee78cdde7d35fa362a.pdf
Amirkabir University of Technology
AUT Journal of Modeling and Simulation
2588-2953
2588-2961
41
1
2009
04
01
Proposing a 2D Dynamical Model for Investigating the parameters Affecting Whiplash Injuries
11
16
EN
Seyed Mohammad
Rajaai
Mohammad H
Farahani
10.22060/miscj.2009.216
This paper proposes a 2D dynamical model for evaluating parameters affecting whiplash. In fact a four segment dynamical model is developed in the sagittal plane for the analysis. The model response is validated using the existing experimental data and is shown to simulate the "S-Shape" and "initial upward ramping" kinematics of the cervical spine and the resulting dynamics observed in human and cadaver experiments. The model is then used to evaluate the effects of parameters such as velocity change between rear vehicle and the target vehicle (), head/head restraint separation (backset) and the awareness of occupant on the whiplash injuries. It is shown that the proposed model can simulate whiplash phenomena very well; therefore it is a suitable alternative for other existing models.
Whiplash injuries,Dynamic model,Adams,Backset,Velocity change,Awareness
http://miscj.aut.ac.ir/article_216.html
http://miscj.aut.ac.ir/article_216_76fc1592ffc07063c0e9d72cf573d8f8.pdf
Amirkabir University of Technology
AUT Journal of Modeling and Simulation
2588-2953
2588-2961
41
1
2009
04
01
Development and Application of an ALE Large Deformation Formulation
17
24
EN
Y.
Tadi benii
M. R.
Movahhedy
G.H.
Farrahi
10.22060/miscj.2009.218
This paper presents a complete derivation and implementation of the Arbitrary Lagrangian Eulerian (ALE) formulation for the simulation of nonlinear static and dynamic problems in solid mechanics. While most of the previous work done on ALE for dynamic applications was mainly based on operator split and explicit calculations, this work derives the quasi-static and dynamic ALE equations in its simple and correct form, using a fully coupled implicit approach. Full expression for the ALE virtual work equations is given. Time integration relations for the dynamic equations are also derived. Examples of quasi-static and dynamic large deformation applications are presented.
FEM,ALE,Large deformation,Coupled formulations,implicit dynamic analysis
http://miscj.aut.ac.ir/article_218.html
http://miscj.aut.ac.ir/article_218_d58283d7e78a9ac38175d1c7b2edefe2.pdf
Amirkabir University of Technology
AUT Journal of Modeling and Simulation
2588-2953
2588-2961
41
1
2009
04
01
Extension of Higher Order Derivatives of Lyapunov Functions in Stability Analysis of Nonlinear Systems
25
33
EN
10.22060/miscj.2009.220
The Lyapunov stability method is the most popular and applicable stability analysis tool of nonlinear dynamic systems. However, there are some bottlenecks in the Lyapunov method, such as need for negative definiteness of the Lyapunov function derivative in the direction of the system’s solutions. In this paper, we develop a new theorem to dispense the need for negative definite-ness of Lyapunov function derivative. We introduce new sufficient conditions for asymptotic stability of equilibrium states of nonlinear systems considering some inequalities for the higher order time derivatives of Lyapunov function. If the above-mentioned inequalities are found, then the stability analysis of an equilibrium state is reduced to check the characteristic equation for a controllable canonical form LTI co-system. The poles of co-system are required to be negative real ones. Some examples are presented to demonstrate the approach.
Nonlinear dynamic systems,Lyapunov methods,Stability Analysis
http://miscj.aut.ac.ir/article_220.html
http://miscj.aut.ac.ir/article_220_693e704136f2c182872d907192957257.pdf
Amirkabir University of Technology
AUT Journal of Modeling and Simulation
2588-2953
2588-2961
41
1
2009
04
01
Delay-Dependent Robust Asymptotically Stable for Linear Time Variant Systems
35
40
EN
D.
Behmardii
Y.
Ordokhaniii
S.
Sedaghatiii
10.22060/miscj.2009.222
In this paper, the problem of delay dependent robust asymptotically stable for uncertain linear time-variant system with multiple delays is investigated. A new delay-dependent stability sufficient condition is given by using the Lyapunov method, linear matrix inequality (LMI), parameterized first-order model transformation technique and transformation of the interval uncertainty in to the norm bounded uncertainty. A numerical example is presented to illustrate our present stability criterion allows an upper bound which is bigger on the size of the delay in comparison with those in the literature.
Lyapunov-Krasovskii Functional,Linear matrix inequality,Parameterized first-order model transformation,Time-delay systems
http://miscj.aut.ac.ir/article_222.html
http://miscj.aut.ac.ir/article_222_e5a28191704179c609b14963a8548bb7.pdf
Amirkabir University of Technology
AUT Journal of Modeling and Simulation
2588-2953
2588-2961
41
1
2009
04
01
Biomechanical Investigation of Empirical Optimal Trajectories Introduced for Snatch Weightlifting
41
47
EN
Shahram
Lenjan Nejadian
Mostafa
Rostami
Ahmad Reza
Arshi
Abolghasem
Naghash
naghash@aut.ac.ir
10.22060/miscj.2009.224
The optimal barbell trajectory for snatch weightlifting has been achieved empirically by several researchers. They have studied the differences between the elite weightlifters’ movement patterns and suggested three optimal barbell trajectories (type A, B, and C). But they didn’t agree for introducing the best trajectory. One of the reasons is this idea that the selected criterion by researchers might not be appropriate. Therefore we build a biomechanical model based on inverse dynamic approach to evaluate each trajectory while considering a specific mechanical criterion. We calculate the optimal motion of each trajectory that minimizes the actuating torques by using dynamic programming approach. We solve an example problem for a specific weightlifter that lifts a 100 (kg) barbell. According to our criterion, we recommend the pattern type C as the best trajectory. The most important result of this simulation is the cost assigned to each trajectory which gives us the ability to evaluate the trajectories clearly. This method is an appropriate tool for coaches to examine each trajectory for any specific weightlifter and make a good decision for selecting the best trajectory.
Sport Biomechanics,Simulation,Dynamic programming,Optimization
http://miscj.aut.ac.ir/article_224.html
http://miscj.aut.ac.ir/article_224_351dae9899ad0356638005364211356f.pdf
Amirkabir University of Technology
AUT Journal of Modeling and Simulation
2588-2953
2588-2961
41
1
2009
04
01
Identification Effect of Nanoclay on Engineering Properties of Asphalt Mixtures
49
57
EN
Saeed
Ghaffarpour Jahromi
Ali
Khodaii
10.22060/miscj.2009.227
Nanoclays are new generation of processed clays of interest in a wide range of high performance composites. In other words, nanoclay is defined as a clay that can be modified to make the clay complexes compatible with organic monomers and polymers. Here, it can be said that the polymeric nanocomposites are among the most exciting and promising classes of materials discovered recently. A number of physical properties are enhanced successfully when a polymer is modified with small amount of nanoclay on condition that the clay is dispersed at nanoscopic level. This research has accomplished a comparative rheological test on binders as well as a mechanical test on asphalt mixtures containing unmodified and nanoclay modified bitumen. For that matter, two types of nanoclay were used: Nanofil-15 and Cloisite-15A. While, the rheological test on binder were penetration, softening point, ductility and aging effect, mechanical test on asphalt mixture were marshal stability, indirect tensile strength, resilient modulus, diametric fatigue and dynamic creep test. Test results show that, nanoclay can improve properties like stability, resilient modulus and indirect tensile strength and possess better behavior compared with unmodified bitumen under dynamic creep although it does not seem to have beneficial effect on fatigue behavior in low temperature. Optimum binder content and void in total mixture (VTM) increase by adding nanoclay to bitumen
Asphalt Mixture,Bitumen Modifies,Nanoclay,Mechanical Properties
http://miscj.aut.ac.ir/article_227.html
http://miscj.aut.ac.ir/article_227_30c16ecd0c5195a1aa8d0fdc8b9b013b.pdf
Amirkabir University of Technology
AUT Journal of Modeling and Simulation
2588-2953
2588-2961
41
1
2009
04
01
Torsion Analysis of High-Rise Buildings using Quadrilateral Panel Elements with Drilling D.O.F.s
59
67
EN
Afshin
Meshkat-Dinii
Mohsen
Tehranizadehii
10.22060/miscj.2009.229
Generally, the finite element method is a powerful procedure for analysis of tall buildings. Yet, it should be noted that there are some problems in the application of many finite elements to the analysis of tall building structures. The presence of artificial flexure and parasitic shear effects in many lower order plane stress and membrane elements, cause the numerical procedure to converge in a low rate. Nevertheless, very large hardware memory storage is needed because of using fine meshes. Hence, it should be better to develop and use elements which can model the structural system of tall buildings in coarse finite element meshes and converge fast. The panel type finite elements presented in this study, have vertical and horizontal degrees of freedom similar to those of wide column analogy in the frame method. There are two rotational degrees of freedom to be defined at the two end of the panel element, which denote the rotational freedom equal to the first derivative of lateral displacement. The proposed elements can simply be used in tall building analysis. The application of the proposed elements can be performed without using a fine mesh. Examples are given to denote the accuracy and efficiency of the presented panel elements.
Tall Building,Quadrilateral Element,In Plane Rotation Degree of Freedom,Strain Based Panel Element
http://miscj.aut.ac.ir/article_229.html
http://miscj.aut.ac.ir/article_229_8080a515fbe5240ffb9b1b81ee76d654.pdf