1
2008-8345
Iranian Society of Instrumentation and Control Engineers
168
Special
Corner Stability in Nonliner Autonomous Systems
Rahimabadi
Arsalan
Taghirad
Hamidreza
1
12
2013
7
3
1
8
02
11
2014
02
11
2014
Inmany practical applications, studying the asymptotic stability of equilibriumpointsof a systemareof utmost importance. Furthermore, in some of such cases the response is restricted to only a sector of the state space. For example positive systems that are really common in chemical processes, have non-negativestate variables. For such systems stability analysis of the system using direct Lyapunov stability is not a suitable choice everywhen, since it suffices to consider of Lypunov conditions in a part of the state space that the existence of solutions is restricted to there andthe existence guarantee of at least a domain that includes the equilibrium point & has the Lypunov conditions, will not be required every time. In this paper a new notion of stability which is called corner stability is defined which is more suitable for studying asymptotic stability of equilibriumpoints in such systems.To derive the sufficient condition of corner stability a theorem is stated in this paper, and fortwo different cases studiescorner stability ofanequilibrium pointattheorigin, is studied according to this theorem.
169
Special
Direct Torque and Flux Control of An Asymmetrical Six-phase Induction Motor Supplied with A Three-level SVPWM Inverter Using Neural Networks Classification
Rastgar Fatemi
S. Mohammad Jalal
Soltani
Jafar
Abjadi
Navid Reza
1
12
2013
7
3
9
15
02
11
2014
02
11
2014
In this research paper a three-level six-phase inverter with space vector pulse width modulation (SVPWM), using two three-level three-phase inverters with 30 degrees phase displacement, is designed. In implementation, neural networks classification is employed for inverter vectors. This inverter is used in a six-phase servo drive system. The using control method is vector control in stator flux reference frame and with a well-known transformation, the six-phase variables are converted to six orthogonal variables. The validity of the proposed method is investigated by six-phase servo drive system simulation.
170
Special
A Robust Control Strategy Based on Reinforcement Learning Approach to Rehabilitat theArm Movement
Hasanzadeh Binabidi
Zahra
Kobravi
Hamidreza
Toosizadeh
Saeed
Boostani
Reza
1
12
2013
7
3
17
30
02
11
2014
02
11
2014
In this research, a control strategy has been presented to movement control of a three link model of humanâ€™s arm. The freezing mechanism has been used to consider the role of antagonistic coactivation of wrist muscles in the used three link model. Inspired by motor learning process of central nervous system, the presented control strategy has been designed based on the reinforcement learning algorithm. At first, the performance of a control methodology based on reinforcement learning was evaluated. The results show the instability of control system even after numbers of leaning episode. Then, a combination of a proportional derivative integral (PID) controller and a reinforcement learning based controller were utilizedtoimprove the stability conditions and performance of controller. Despite the good performance, there is no guarantee for stability of control system. So, to satisfy the stability conditions, a robust controller called HTC was added to thecombination of a PID controller and a reinforcement learning based controller. According to the simulation results, the combinational controller accompany by HTC had good performance even in presence of external disturbance, measurement noise and random changes of model parameters. For more assessments, the muscle activation profile of involved muscles during the arm movement of an intact subject was compared with control signals obtained through the simulation studies. The results show an interesting timing synchronization between the activation and deactivation timing of control signals and muscle activation profiles.
171
Special
Analysis and Design of Optimum Time Delay in Warhead Detonation
Parsanejad
zahra
Heyrani Nobari
Jafar
Ebadollahi
Saeed
1
12
2013
7
3
31
40
02
11
2014
02
11
2014
Fuse is one of the most important factors on killing probability of weapon system. The function performed by the proximity fuse is to sense the presence of a target and detonate the warhead at a suitable point to maximize the probability of destroying the target. In this paper, time delay problem is solved since detection time to detonation time in tow-dimensional inertial system. Considering the fuse sensor center as inertial point, simple equation is derived for time delay which the way of influence the factors can be seen well. Due to the inability on measure all influential factors,this present research is going to offer optimal estimation of time delay with less factors. Primarily, according to the criterion td > 0, suitable value for lean angle fuse is selected.Next, constant value is offered for time delay. By this constant value, fragments won't strike to target at all possible engagement scenarios. So, time delay would be designed as function of missile and target relative velocity.
172
Special
Robust Fault Detection and Isolation to Compressible Systems Using Bond Graph Approach
Sanei
Ahmad
Basohbat Novinzadeh
Alireza
1
12
2013
7
3
41
52
02
11
2014
02
11
2014
In the papers published on Fault Detection and Isolation(FDI) using Bond Graph approach, robust FDI in the compressible flow systems has less been developed in the literature, due to the strong nonlinearities in this systems. In this paper, Bond Graph model in LFT form is developed for compressible systems. The results of this research are shown the causal properties of bond graph can be used to obtain the Analytical Redundancy Relations (ARRs) in presence of parameter uncertainties. The advantage of the bond graph model in LFT form is generation of ARRs and decoupling of the nominal part from the uncertain part. The nominal part can be used to calculate of the residual and the uncertain part can be used to obtain of adaptive thresholds and sensitivity analysis. In the following, the developed model is validated by pedagogical example.
173
Special
Relation between Transfer Function Entries and the RGA Entries and Its Application in Decentralized Controllers Design
Shahmansoorian
Aref
1
12
2013
7
3
53
57
02
11
2014
02
11
2014
Relative gain array (RGA) possible values are investigated. It is shown that in plants RGA in zero frequency can not be equal to any value nevertheless it can be equal to arbitrary values in nonzero frequencies. The relation between the entries of transfer function and that of RGA is presented. Transfer function entries are parameterized with respect to entries of RGA. This parameterization can be used for designing compensators such that RGA of compensated system has desirable form.