Mohamad R. Askari

Adaptive cruise control with stop&go function using the state-dependent nonlinear model predictive control approach.

In the design of adaptive cruise control (ACC) system two separate control loops - an outer loop to maintain the safe distance from the vehicle traveling in front and an inner loop to control the brake pedal and throttle opening position - are commonly used. In this paper a different approach is proposed in which a single control loop is utilized. The objective of the distance tracking is incorporated into the single nonlinear model predictive control (NMPC) by extending the original linear time invariant (LTI) models obtained by linearizing the nonlinear dynamic model of the vehicle. This is achieved by introducing the additional states corresponding to the relative distance between leading and following vehicles, and also the velocity of the leading vehicle. Control of the brake and throttle position is implemented by taking the state-dependent approach. The model demonstrates to be more effective in tracking the speed and distance by eliminating the necessity of switching between the two controllers. It also offers smooth variation in brake and throttle controlling signal which subsequently results in a more uniform acceleration of the vehicle. The results of proposed method are compared with other ACC systems using two separate control loops. Furthermore, an ACC simulation results using a stop&go scenario are shown, demonstrating a better fulfillment of the design requirements.

Adaptive Cruise Control System: Comparing Gain-Scheduling PI and LQ Controllers

Abstract Over the recent years, a considerable growth in the number of vehicles on the road has been observed. This increases importance of vehicle safety and minimization of fuel consumption, subsequently prompting manufacturers to equip cars, with more advanced features such as adaptive cruise control (ACC)or collision avoidance and collision warning system (CWS). This paper investigates two control applications design namely the gain scheduling proportional-integral (GSPI) control and gain scheduling Linear Quadratic (GSLQ)control for ACC, covering a high range speed. The control system consist of two loops in cascade, with the inner loop controlling the vehicle speed and the outer loop switching between the cruise control (CC) and the ACC mode and calculating the reference speed. A nonlinear dynamic model of the vehicle is constructed and then a set of operating points is determined and then a of linear models is extracted in operating point. For each operating point, PI and LQ controllers are obtained off-line. An integrated Simulink model including the nonlinear dynamic vehicle model and the ACC controller (either PI or LQ) was used to test the controllers in various traffic scenarios. Comparison results between the two controllers applications is provided to show the validity of the design.

The experimental analysis of vibration monitoring in system rotor dynamic with validate results using simulation data

There is a growing tendency today to extract information about the prognostic parameters based on system analysis through various diagnostic techniques to assess the health of the plant or equipment. Vibration monitoring helps in reducing the machine down time. A vibration signature measured at the external surface of machine or at any other suitable place contains a good amount of information to reveal the running condition of the machine. Considering the importance of vibration monitoring in the rotating machinery fault diagnostics, it has been applied in this paper. Effects of modal parameters like natural frequency, mode shapes, and damping, misalignments have been studied. Balancing is usually an expensive and laborious procedure and a balancing system would be beneficial for motor engine and power generation application. In this research, there have been identified unbalance parameters that exist in rotating machinery and develop a finite-element model of rotating dynamics system to create a mathematical model of the system from the test data and subsequently obtaining the unbalanced parameters. During this study, the raw data obtained from the experimental results (Smart Office software) are curve fitted by theoretical data regenerated from simulating it using finite element (ANSYS 12) model for comparisons. The experimental analysis used thus far is called Modal Testing, a well-known and widely used technique in research and industry to obtain the Modal and Dynamic response properties of structures. The technique has recently been applied to rotating structures and some research papers been published, however, the full implementation of Modal Testing in active structures and the implications are not fully understood and are therefore in need of much further and more in-depth investigations. The aim is to find a system identification methodology using the analytical/computational techniques and update the model using experimental techniques already established for passive structures but to active rotating structures, which subsequently help to carry out health monitoring as well as further design and development in rotating machinery.

Improvement of safety engineering design in rotating structures by detection of resonance frequency signals

Rotor Dynamics is the study of dynamics and stability of rotating machinery, and it plays an important role in improving the safety and performance of the systems that it is a part of. Rotating machinery is seen in several applications in our daily life. These include machine tools, power stations, turbo-machinery, aircraft jets, automobiles, and marine propulsion, among others.

Defect Diagnosis in Rotors Systems by Vibrations Data Collectors Using Trending Software

Vibration measurements have been used to reliably diagnose performance problems in machinery and related mechanical products. A vibration data collector can be used effectively to measure and analyze the machinery vibration content in gearboxes, engines, turbines, fans, compressors, pumps and bearings. Ideally, a machine will have little or no vibration, indicating that the rotating components are appropriately balanced, aligned, and well maintained. Quick analysis and assessment of the vibration content can lead to fault diagnosis and prognosis of a machine’s ability to continue running. The aim of this research used vibration measurements to pinpoint mechanical defects such as (unbalance, misalignment, resonance, and part loosening), consequently diagnosis all necessary process for engineers and technicians who desire to understand the vibration that exists in structures and machines.