Showing 5 results for Rahman
Prof. Dr. Ataur Rahman, Mr Mohammad Amysar,
Volume 8, Issue 2 (6-2018)
Abstract
ABSTRACT: Deceleration or stopping the vehicle without any diving and lateral acceleration is essential to develop an effective braking system. The hydraulic braking system with intelligent braking called Antilock Braking system (ABS) and Electronic Stability Control (ESC) has been introduced. However, due to the insufficient human effort, the ABS and ESC to some extent, not function well. This has been emphasised to develop a DC motor assist hydraulic braking system by associating the wheel speed and engine fuel flow sensor to stop the vehicle in required braking distance without any diving and lateral movement. This study investigates theoretically by Solid work simulation model and experimentally by product development. The simulation model has shown that a full load passenger car needs 15.7Mpa of braking pressure to stop 50km/h vehicle in 10m. The experimental results of the model show that the pressure develops when the pedal fully applied without and with aids of the DC motor is 910 kPa and 1130 kPa respectively, which contribute to 23.3% of pressure increase.
KEYWORDS: DC motor assist hydraulic braking system; Digital Control System; Braking efficiency.
Mr. Hamed Rahmanian, Dr. Alireza Sadeghi, Dr. Ali Asghar Ataee,
Volume 10, Issue 1 (3-2020)
Abstract
Application of Mg alloy parts in automotive industry is increasing to reduce weight and fuel consumption. One of the high potential parts for application of Mg alloys is the front seat frame. However, change of material is accompanied by change of manufacturing process and change of design for the seat frame. In the present research while keeping the reference overall ergonomic outline, a new substitute Mg alloy design was proposed, featuring a simple easy to manufacture Z profile. Next, a two-stage optimization technique (size and shape) is proposed for the Mg seat frame based on the stress and displacement criteria of standard test plans. The final optimized design is close to fully-stressed state and is 70% lighter than the reference steel backrest.
Mr. Mohammad Yar-Ahmadi, Mr. Hamid Rahmanei, Prof. Ali Ghaffari,
Volume 13, Issue 1 (3-2023)
Abstract
The primary purpose of each autonomous exit parking system is to facilitate the process of exiting the vehicle, emphasizing the comfort and safety of driving in the absence of almost any human effort. In this paper, the problem of exit parking for autonomous vehicles is addressed. A nonlinear kinematic model is presented based on the geometric relationship of the vehicle velocities, and a linear time-varying discrete-time model of the vehicle is obtained for utilizing the optimal control strategy. The proposed path planning algorithm is based on the minimization of a geometric cost function. This algorithm works for ample space exit parking in Single-Maneuver and tight spaces in Multi-Maneuver exit parking. Finally, an optimal discrete-time linear quadratic control approach is hired to minimize a quadratic cost function. To evaluate the performance of the proposed algorithm, the control system is simulated by MATLAB/Simulink software. The results show that the optimal control strategy is well able to design and follow the desired path in each of the exit parking maneuvers.
Mr. Hamid Rahmanei, Dr. Abbas Aliabadi, Prof. Ali Ghaffari, Prof. Shahram Azadi,
Volume 13, Issue 2 (6-2023)
Abstract
The coordinated control of autonomous electric vehicles with in-wheel motors is classified as over-actuated control problems requiring a precise control allocation strategy. This paper addresses the trajectory tracking problem of autonomous electric vehicles equipped with four independent in-wheel motors and active front steering. Unlike other available methods presenting optimization formulation to handle the redundancy, in this paper, the constraints have been applied directly using the kinematic relations of each wheel. Four separate sliding mode controllers are designed in such a way that they ensure the convergence of tracking errors, in addition to incorporating the parametric and modeling uncertainties. The lateral controller is also designed to determine the front steering angles to eliminate lateral tracking errors. To appraise the performance of the proposed control strategy, a co-simulation is carried out in MATLAB/Simulink and Carsim software. The results show that the proposed control strategy has enabled the vehicle to follow the reference path and has converged the errors of longitudinal and lateral positions, velocity, heading angle, and yaw rate. Furthermore, the proposed control system shows promising results in the presence of uncertainties including the mass and moment of inertia, friction coefficient, and the wind disturbances.
Mr Seyed Amir Mohammad Managheb, Mr Hamid Rahmanei, Dr Ali Ghaffari,
Volume 14, Issue 1 (3-2024)
Abstract
The turn-around task is one of the challenging maneuvers in automated driving which requires intricate decision making, planning and control, concomitantly. During automatic turn-around maneuver, the path curvature is too large which makes the constraints of the system severely restrain the path tracking performance. This paper highlights the path planning and control design for single and multi-point turn of autonomous vehicles. The preliminaries of the turn-around task including environment, vehicle modeling, and equipment are described. Then, a predictive approach is proposed for planning and control of the vehicle. In this approach, by taking the observation of the road and vehicle conditions into account and considering the actuator constraints in cost function, a decision is made regarding the minimum number of steering to execute turn-around. The constraints are imposed on the speed, steering angle, and their rates. Moreover, the collision avoidance with road boundaries is developed based on the GJK algorithm. According to the simulation results, the proposed system adopts the minimum number of appropriate steering commands while incorporating the constraints of the actuators and avoiding collisions. The findings demonstrate the good performance of the proposed approach in both path design and tracking for single- and multi-point turns.
