This paper reports a comparative experimental evaluation of proportional derivative and adaptive modelbased control for underwater vehicles. To the best of the authors’ knowledge, this is the first such evaluation of modelbased adaptive tracking control for underwater vehicles during simultaneous dynamic motion in all 6 degrees-of-freedom. This experimental evaluation revealed the presence of u...

In this paper, an innovative mobile platform is presented which is equipped by three new wheels. The core of the new idea is to establish a new design of rigid circular structure which can be implemented as a wheel by variable radius. The structure of wheel includes a circular pattern of a simple two-link mechanism assembled to obtain a wheel shape. Each wheel has two degrees of freedom. The fi...

The Reynolds equation is extended to include the effects of radial deflection in a seal with two flexibly mounted rotors. The resulting pressures are used to obtain the forces and moments introduced in the axial and angular modes by the inclusion of eccentricity in the analysis. The rotor dynamic coefficients relating the forces and moments in these modes to the axial and angular deflection are...

We introduce a variant of the multi-grid Monte Carlo (MGMC) method, based on the embedding of an XY model into the target model, and we study its mathematical properties for a variety of nonlinear σ-models. We then apply the method to the twodimensional O(N)-symmetric nonlinear σ-models (also called N -vector models) with N = 3, 4, 8 and study its dynamic critical behavior. Using lattices up to...

For motion planning it is important to have an accu rate dynamic system model and in many cases friction is an important component of the model It is known however that when Coulomb friction is added to the rigid body dynamic equations the forward dynamic solution may not exist and if it exists it is not necessarily unique In this paper we study the existence and uniqueness prop erties of the f...

One of the most efficient methods of reducing drag on planing craft is the use of transverse step on the bottom of a hull. Applying steps on the hull reduces the contact area with water and as a result, it reduces drag of the craft. Planing craft are able to have one or two transverse steps. In this paper, numerical hydrodynamic performance of the stepped planing craft and its step height effec...

The vibrations produced by trains include two parts which are deterministic and random vibrations. Due to variation of dynamic loads and patterns of load-time, the random vibration of moving train is one of the most important issues in the field of railway engineering. One of the important sources in producing the train vibrations is rail roughness and irregularities. In this paper, responses o...

this paper studies the dynamic behavior of price elasticity and its effects on the overall profit. although price elasticity has a significant effect on sales, its dynamics have not been examined so far in pricing models. in this paper, a simple pricing model is suggested in which, price elasticity is considered dynamic. the suggested pricing model is concerned with a monopolist that its object...

Series solution of nonlinear dynamic system containing fractional derivative is obtained by the homotopy analysis method (HAM). The solution via HAM has auxiliary parameter h̄ which can control the convergent of the series to obey the exact or numerical solution. The model of viscoelastic behavior of a one-degree-of-freedom oscillator consisting of a discrete mass and a viscoelastic spring is co...

We study the Langevin dynamics of flux lines of high–Tc superconductors in the presence of random quenched pinning. The hydrodynamic theory for the densities is derived by starting with the microscopic model for the flux-line liquid. The dynamic functional is expressed as an expansion in the dynamic order parameter and the corresponding response field. We treat the model within the Gaussian app...