In recent years, underactuated nonlinear dynamic systems trajectory tracking, such as space robots and manipulators with structural flexibility, has become a major field of interest due to the complexity and high computational load of these systems. Hierarchical sliding mode control has been investigated recently for these systems; however, the instability phenomena will possibly occur, especia...

Mobile computer users often have a false sense of anonymity when they connect to the Internet at cafes, hotels, airports or other public places. In this paper, we analyze information leaked by mobile computers to the local access link when they are outside their home domain. While most application data can be encrypted, there is no similar protection for signaling messages in the lower layers o...

In this paper, a robust control system with the fuzzy sliding mode controller and the additional compensator is presented. The additional compensator relaying on the slidingmode theory is used to improve the dynamical characteristics of the drive system. Sliding mode control method is studied for controlling DC motor because of its robustness against model uncertainties and external disturbance...

The mobile satcom antenna (MSA) enables a moving vehicle to communicate with a geostationary Earth orbit satellite. To realize continuous communication, the MSA should be aligned with the satellite in both sight and polarization all the time. Because of coupling effects, unknown disturbances, sensor noises and unmodeled dynamics existing in the system, the control system should have a strong ad...

Chattering is undesirable phenomenon when dealing with sliding mode control. This paper proposed a new method for addressing chattering with a simple and easy implementation in Digital Signal Processor (DSP). This is realized by replacing the discontinuous function in conventional sliding mode control with statedependent auto-tuning of boundary layer in fast sigmoid function and state-dependent...

Sliding control guarantees system performance in the presence of modeling uncertainties and parameter inaccuracies. However this is obtained at the price of high control activity that may exacerbate chattering. As one way to alleviate this problem a continuation method using boundary layer around switching is usually used. In this case selecting the control bandwidth and boundary layer thicknes...

We consider hybrid systems of differential-algebraic equations and present a general framework for general nonlinear overand underdetermined hybrid systems that allows the analysis of existence and uniqueness and the application of index reduction methods for hybrid differential-algebraic systems. A particular difficulty in the numerical simulation of hybrid systems is (numerical) chattering, i...

A sliding mode control method is presented for linear multi-variable discrete-time systems, without introducing a discontinuous term to eliminate control chattering. Instead of a strong nonlinear function like switching introducing chattering problem in discrete-time, a linear control is designed around the sliding surface. Although not producing a strong acting control around the sliding surfa...

The use of a boundary layer in sliding-mode control has been a common technique to reduce chattering of the control signal. However, different choices of the boundary layer width lead to conflicting effects: a large/small boundary layer width can more/less effectively alleviate the chattering phenomenon, but leads to less/more accurate control results. This note proposes online adjusting the wi...

Geared Dc motors can be controlled by many controllers which may include the conventional PID controllers and various other techniques. The sliding mode control is one of the good controllers which can be used for conditions like disturbances and parameter variations. The system responses are compared when PID controller is applied to the system. SMC methods yield nonlinear controllers which ar...