Sharif Digital Repository

In this paper, designing of the LQR controller and observer with intelligent tools for the triple inverted pendulum is investigated. Intelligent tools are considered as GA and GA-PSO optimization algorithms and fuzzy logic to qualify achieving LQR gains. The pendulum is swung up from the vertical position to the unstable position. The rules for the controlled swing up are heuristically achieved such that each swing results are controlled. The inverted pendulum and cart system are modeled and constructed their equation based on energy method. Also, the performances of the proposed fuzzy logic controller, GA and GA-PSO tuning LQR gains are investigated and compared. Simulation results show... 

This study investigates the chaotic response of the spring-pendulum system. In this system besides of strange attractors, multiple regular attractors may co-exist for some values of system parameters, and it is important to study the global behavior of the system using the basin boundaries of the attractors. Here multiple scales method is used to distinguish the regions of stable and unstable attractors. Early studies show that there are unstable regions for the spring-pendulum system. In this study using bifurcation diagrams and Poincaré maps, it is shown that in some cases the response becomes quasi-periodic or chaotic for some deviations from external and internal resonance frequencies.... 

In this paper, a new highly convergent, efficient, and fast response control technique entitled as fuzzy-Padé control method is introduced. It provides a simple methodology to exploit the heuristic knowledge in controlling a system. Fuzzy-Padé controllers originate from a unification of heuristic knowledge expressed as the rule base, and Padé approximants. In this method, fuzzy singleton rules are used to generate the rule base. Accordingly, unknown parameters in the Padé approximant are determined using these rules. The fuzzy-Padé controllers possess certain advantages over fuzzy controllers, and they can be applied in situations where fuzzy controllers previously failed. To demonstrate the... 

Human posture control is a complex issue in biomechanics. Human body is unstable without any controller. The stabilization of the body is achieved by the activation of the muscles and creating the joint torques. In this paper, human body in upright standing position has been modeled using an inverted double pendulum. Since the body parameters are different among the individuals, it is assumed that these parameters are not known exactly and are uncertain. An adaptive controller based on the inverse dynamics in addition to parameter adaptation law has been designed. The simulation of the system using this controller shows the effectiveness of the proposed method in controlling the human... 

In this paper, the nonlinear oscillation of a pendulum wrapping and unwrapping on two cylindrical bases is studied, and an analytical solution is obtained using the multiple scales method. The equation of motion is derived based on an energy conservation technique. By applying the perturbation method to the differential equation, the nonlinear natural frequency of the system is calculated, along with its time response. Analytical results are compared with numerical findings and good agreement is found. The effect of large amplitude and radius of cylinders on system frequency is evaluated. The results indicate that as the radius of the cylinder increases, the system frequency is increased.... 

In present paper, a feedback linearization control is applied to control a chaotic pendulum system. Tracking the desired periodic orbits such as period-one, period-two, and period-four orbits is efficiently achieved. Due to the presence of saturation in real world control signals, the stability of controller is investigated in presence of saturation and sufficient stability conditions are obtained. At first feedback linearization control law is designed, then to avoid the singularity condition, a saturating constraint is applied to the control signal. The stability conditions are obtained analytically. These conditions must be investigated for each specific case numerically. Simulation... 

Inverted pendulum (IP) has been broadly used to model locomotor systems. In this paper, we demonstrate that an IP-like model could simulate stable periodic handspring maneuvers with passive flight phases. The model is a 2-D symmetric rigid body which is merely controlled during the contact phase. To benefit from an open-loop sensorless strategy, the control policy is implemented only by an unvaried torque input. The system's dynamics is an example of nonlinear impulsive systems studied and analyzed by the Poincaré section method. The numerical results reveal that the stable periodic solutions are sufficiently robust for a broad range of the parameter space. © 2020 Elsevier Ltd  

It is a great challenge for the universities to present undergraduate students the fundamental knowledge needed to develop intelligent unstable robots. Due to the inherent instability and nonholonomic constraints, the problem of two-wheeled inverted pendulum (TWIP) mobile robot is appealing and challenging case in control and dynamic systems. In this paper, an approach is presented to introduce undergraduate students of the control engineering, the principle of developing a. TWIP mobile robot. For this purpose, a. conceptual design algorithm for TWIP robots is contributed and based on the algorithm and the design criteria, a. prototype of the robot is constructed. In the construction... 

In this paper a novel fuzzy approach exploiting Active Learning Method is employed in order to estimate the immeasurable states required to control a non-observable double inverted pendulum. Active Learning Method (ALM) is a fuzzy modeling method which exploits Ink Drop Spread (IDS) as its main engine. IDS is a universal fuzzy modeling technique which is very similar to the way human brain processes different phenomena. The ALM system is trained by the data obtained from Linear Quadratic Regulator (LQR) controller. LQR uses an optimal control approach which under certain conditions guarantees robustness. Instead of an expert's knowledge, the LQR controller output is used as a priori... 

In this paper, the swing-up problem of the Furuta pendulum has been solved by introducing a new combined method based on the frequency response, and the sliding mode method. Furthermore, a trajectory tracking controller has been introduced and applied to the Furuta pendulum; which the pendulum remained regulated at the upward position, while the arm tracks a desired time-varying trajectory. The hierarchical sliding mode control (HSMC) approach has been employed to achieve the mentioned goals. The Furuta system is made up of two subsystems. Based on this physical structure, the hierarchical structure of the sliding surfaces is designed as follows: first, the sliding surface of each subsystem... 

This paper presents a fuzzy-based interaction prediction approach (F-IPA) for two-level optimal control of large-scale systems. The design procedure uses a decomposition/coordination framework of hierarchical structures. At the first level, the system is decomposed into subsystems for which subproblems are formed. At the second level, a fuzzy coordinator is used to predict the coordination parameters needed to coordinate the solutions of the first level subproblems. The fuzzy coordinator uses a critic vector to evaluate its performance and learn its parameters by minimizing an energy function. The proposed control scheme is implemented on a two-degrees-of-freedom (2DOF) model of robot... 

Sliding friction between a pavement and tire is an important concern in traffic safety. The British pendulum test has been used worldwide to evaluate friction characteristics of pavement surfaces. However, because of considerable differences in apparatus, procedures, and operation, significant variability can occur for evaluations of British pendulum number (BPN). In this investigation, a direct shear test (DST) device is modified and proposed to determine the sliding friction coefficient between tire and pavement surface under dry and wet conditions. Dissipated energy values obtained from DST were compared with evaluations of BPN, and a high correlation was obtained. Tests were done using... 

In this paper, an indirect adaptive fuzzy sliding mode controller for a 3-dimensional inverted pendulum as a fully actuated MIMO system is developed. This inverted pendulum, has four degrees of freedom and equations of the system are nonlinear and non-minimum phase. Thus, control of this system is a challenging issue. Accordingly, in this work, general basis of sliding mode control method with reaching rules is expressed for this system, then the fuzzy control theory is combined, and modeling uncertainties of the system are estimated by universal fuzzy approximation theory. Controller parameters are updated by a defined adaptation law to decrease the tracking error of the inverted pendulum.... 

Preventive pavement maintenance methods such as slurry seals are cost-effective treatments that increase the longevity of pavements. The incorporation of recycled materials such as reclaimed asphalt pavement (RAP) into asphalt pavement helps to further reduce costs and energy consumption. The present research studied the feasibility of incorporating RAP into slurry seal mixtures or RAP slurry seals. Two slurry seal mixtures containing cement and hydrated lime as fillers were tested. The first mixture comprised slurry seal made with virgin aggregate and the second used RAP as the aggregate. The wet track abrasion test (WTAT) and loaded wheel test (LWT) were conducted to evaluate the... 

Gaining insight into possible vibratory responses of dynamical systems around their stable equilibria is an essential step, which must be taken before their design and application. The results of such a study can significantly help prevent instability in closed-loop stabilized systems by avoiding the excitation of the system in the neighborhood of its resonance. This paper investigates nonlinear oscillations of a rotary inverted pendulum (RIP) with a full-state feedback controller. Lagrange’s equations are employed to derive an accurate 2-DoF mathematical model, whose parameter values are extracted by both the measurement and 3D modeling of the real system components. Although the governing...