A second-order sliding mode control is used for high-order uncertain plants using equivalent control approach to improve the performance of control systems. They combine backstepping with quasi-continuous controller and twisting controllers. This paper considers a two of the most popular controllers that are used to solve the nonlinearities problem which are the backstepping quasi-continuous control (BQCC) and backstepping twisting controllers to control the angular velocity of a hydraulic motor to improve tracking performance and robustness to uncertainties. For the system dynamics, a linear state feedback with suitable high gain was designed as the virtual controller, where steady state error can be made arbitrarily small according to the gain value. A time varying sliding variable was then selected based on the designed virtual controller. The main benefit of using time varying sliding variable is that the system torque required is initially zero, in addition to the fact that its increasing rate can be put in a suitable range. The system’s stability analysis has been presented using the Lyapunov function in the low level subsystem. The second order control action was used for the high level subsystem and the conventional sliding mode is used for the low level subsystem. The performance and the robustness of the proposed control in forcing the angular velocity to track the reference value (100-2000 RPM) with uncertainty of (+10%) and disturbances of (5-30 N.m) in the system parameters were studied. First, the mathematical model of the system was created. Then, Matlab-based simulation was used to assess the system performance. The results showed that the system exhibits excellent performance and robustness for multi-step input and multiplicative uncertainty. © 2024, Cefin Publishing House. All rights reserved.
To assess the feasibility of using a faecal occult blood test (FOBT) kit as a screening tool for periodontal disease. Additionally, the study aimed to evaluate the test's sensitivity and specificity while exploring the influence of factors like age, sex and the number of teeth on its performance.
A prospective observational case–control study involving 150 participants divided into three groups on the basis of the basic perio
Background: Marginal adaptation is critical for long – term success of crown and bridge restoration. Computer aided design / computer aided manufacture (CAD/ CAM) system is gaining more importance in the fabrication of dental restoration. Objective: The aim of this study is to evaluate the effect of crystallization firing on the vertical marginal gap of IPS. emax CAD crowns which fabricated with two different CAD/CAM systems .Materials and Methods: Twenty IPS e.max CAD crowns were fabricated. We had two major groups (A, B) (10 crowns for each group) according to the CAD/CAM system being used: Group A: fabricated with Imes - Icore CAD/CAM system; Group B: fabricated with In Lab Sirona CAD/CAM system. Each group was subdivided into two s
... Show MoreThe implementation of the concept of project scheduling in the organizations generally requires a set of procedures and requirements, So, most important of all is the understanding and knowledge of the tools and techniques which are called the methods of scheduling projects. Consequently, the projects of the municipality administration in the holy governorate of Karbala suffer from the problem of delaying their projects and chaos in the ways of implementation. To provide assistance to this directorate and to demonstrate how to schedule projects using one of the advanced scientific methods that proved their ability to schedule any project and its potential to accelerate the time of completion, as well as ease of use and effectiven
... Show MoreSeveral studies have indicated that more than 600 cities in the world (intermas of rapid growth and development) will generate about 60% of international economic growth between 2010 and 2025 . by 2025 , 66% of the worlds population will live in urban areas the management of cities will face challenges that accompany this increase in the population which requires preparing to face these challenges and problems and the need to provide the aim of the research to know the readiness of Baghdad city to implement the strategies of urban management throught on asmple representing the ( Advisiry group for the comprechnsive development plan for the city of Baghdad 2030 and its supporters ) in the municipality of Baghdad and the number of
... Show MoreThe present study analyzes the violation of the strategies of conversation in two English plays namely Richard II and King Lear. The present study tries to achieve the following goals: 1. showing how the strategies of real conversation can be applied to conversation in plays. 2. analyzing how the characters communicate with each other to discover how Shakespeare violates the strategies of conversation in depicting his characters. The study has been conducted on the bases of the following hypotheses:
- The strategies of conversation which are derived from the study of natural conversation can be applied to conversation in drama with some modification for dramatic purposes.
The shoulder and hip joints though essentially both are ball and socket joints, show structural variability to serve functional needs.
This study aims at revealing some of the structural and functional properties of each of the two joints regarding the factors that contribute to the stability of any joint in the body, namely: bone, ligament, and muscle.