Papers by Mohammad Gohari
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Journal of vibration engineering & technologies, Jun 26, 2022
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WSEAS TRANSACTIONS ON SYSTEMS
Robot tasks and functions are advanced by IoT, remote working, and new human lifestyle requiremen... more Robot tasks and functions are advanced by IoT, remote working, and new human lifestyle requirements in tedious or accurate occupations such as surgery, product inspections, or agriculture harvesting. Numerous robots are technologically advanced by scientists for diverse tasks. Flexible robots are developed based on stated applications since they can adjust their geometry to the working situations. The present study introduces a wire-driven flexible robot stimulated by animal trunks. It can make a motion in planar and space based on the construction of that. Initially, a kinematic model was developed to predict end-effector trajectory, and then a dynamic model was established to compute the required tension of tendon wires based on bending beam theory. Models are simulated by MATLAB/SIMULINK Software and implemented by a generic controller. Various input functions are applied to the model, and outputs show good stability and accuracy. Based on these results, in future work, a WDFR wi...
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Mechanic of Advanced and Smart Materials
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Control Systems and Optimization Letters, May 15, 2023
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SSRN Electronic Journal, 2022
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HighTech and Innovation Journal, 2022
Automobile passengers are usually sensitive to the noises generated by the engine and vehicle bod... more Automobile passengers are usually sensitive to the noises generated by the engine and vehicle body. One of the noise sources is the generated turbulent flow around the Vehicle Side View Mirror (VSVM) and around the A-pillar, producing fluctuating pressure. Unwanted noise is a result of fluctuating pressure around the car's body. Modification of the geometry of the vehicle body may affect the generated noise by turbulent flow. In this paper, the original side view mirror of a small sedan car named Tiba was aimed at geometry modification to decrease airborne noise. The mirror was assessed by CFD simulation and an outdoor test. Road tests were applied at three forward speeds (80, 100, and 120 km/h) to measure the sound level generated by the vehicle's side mirrors. Then, the geometry of VSVM was modified to diminish the sound pressure level of that based on decreasing turbulent flow and fluctuating pressure around the side mirror. Finally, the achieved geometry was evaluated us...
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Article history: Received 22 February 2020 Received in revised form 5 June 2020 Accepted 23 June ... more Article history: Received 22 February 2020 Received in revised form 5 June 2020 Accepted 23 June 2020 Available online 11 July 2020 The high level of transmitted noise and vibrations of a helicopter flight to the aircrew body can cause discomfort and perhaps affect their performance and physical condition. This paper presents an active seat suspension system with intelligent active force control (AFC) using an artificial neural network (ANN), iterative learning (IL) algorithm, and fuzzy logic (FL) to reduce vibration on the helicopter seat. Therefore, three control schemes are considered for this application, namely AFCANN, AFCIL, and AFCFL. Computer simulations have been performed using MATLAB software to verify the proposed control schemes. The pilot head displacement, acceleration, and also seat acceleration transmissibility are selected as target variables. The simulation results illustrate that the usage of proposed control schemes leads to effective control of target variables...
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One of the essential components of rotary systems is bearing which is supporting load of rotor. A... more One of the essential components of rotary systems is bearing which is supporting load of rotor. Active magnetic bearings can remove contact point between rotor and supports by magnetic force. Controlling magnetic force is key point of this system to keep mechanical balancing of rotor. Due to high revolution speed of rotors, disturbances produce instability. The Disturbance Observer Algorithm (DO) is an approach to reduce effects of disturbances. The DO Controller was combined to generic PID Controller to improve performance of AMB. In DO, estimation mass is vital to enhance stability and accuracy of that. So, artificial neural network and iterative learning were hybridized to DO as intelligent techniques in estimation mass. Simulation assessment reveals iterative learning showed superior results in terms of accuracy and stability of AMB responses to the disturbances.
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Measurement, 2019
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New Journal of Chemistry, 2015
This novel adsorptive nanocomposite ultrafiltration membrane is effective in removing arsenate (A... more This novel adsorptive nanocomposite ultrafiltration membrane is effective in removing arsenate (As(v)) from water sources for drinking water production.
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In conventional tillage systems, uniform depth tillage is applied over the entire field; however,... more In conventional tillage systems, uniform depth tillage is applied over the entire field; however, the depth of hardpan layer varies greatly within the field. Site-specific tillage, which modifies physical properties of soil only where the tillage is needed for crop growth, could achieve significant savings in fuel consumption and drawbar power requirements. Site-specific tillage can be implemented either with (1) a pre-tillage map technology, or (2) a real-time sensor. The pre-tillage map technology would be a two-step process in which a sensor such as a soil cone penetrometer would be employed to develop maps showing the existence of hardpan and its depth. This map would then be used in the site-specific tillage equipment control system to control tillage implement location and depth. The real-time sensor would provide a one-step system to control tillage implement location and depth. In this research, a GPS-based variable-depth tillage implement was developed and evaluated. While the tractor is moving, a laptop receives the location of the tractor through the GPS, and then based on the soil compaction map, the controller dictates the depth of tillage implement. The variable-depth tillage implement was first calibrated in the workshop. The response time of the electro-hydraulic system was assessed. Then, the variable-depth tillage implement was evaluated under field conditions. The time required for the implement to reach the set depth under two ground speeds (2.6 and 3.6 km h-1) was determined. Stress analysis of the designed tillage implement, using a finite-element method, showed that the implement benefited from enough strength. The response time was increased linearly with depth, i.e., 3.7 cm depth increase per second. The accuracy and precision of the control system for changing the depth were 1.2 and 0.83%, respectively. The results showed that by considering the response time of the system and the travel speed of the tractor, the control system can be activated such that the variable-depth tillage implement reaches to the desired depth by the time it approaches the next expected depth changing zone.
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The most usual way of using chemical method to protect crop against weed, insects, and fungi is s... more The most usual way of using chemical method to protect crop against weed, insects, and fungi is spraying the mixture of chemicals and water onto crop through the nozzles. Sprayers usually moved on the field by tractor, and tractor induced unwanted vibration to sprayer because of uneven soil or terrain. This oscillation leads to over-doses and under-doses of chemical sprayed on the field. For this reason, many commercial and some theoretical suspension were made to reduce undesirable vibration. Therefore, in this study a finite element based model was established to represent the dynamic behavior of spray boom structure with 8m width. The first tenth natural frequencies were obtained between 9.25 Hz to 1,182.5 Hz. Also, a passive vertical suspension was designed to remove unwanted vibration with 0.5 vibration transmissibility. Finally, the suspension system was simulated to be as certain of its efficiency. The results of simulation have good agreement to the proposed aim.
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Little is known about effects of spine fixation by implants on the human body responses to the ha... more Little is known about effects of spine fixation by implants on the human body responses to the harmonic vibrations. Most of researches are about pressure on the vertebrae or degree of freedom after this treatment on the spine. The aim of this paper is determining effects of spine fixation on the mobility and vibration transmissibility of spine. Kitazaki (1992) model was used for simulation. Five scenarios were done on the model. Health spine, spine model with fixation at L3, T11, T6, and L3 & T11 together were exposed to the harmonic vibration, and pelvic to head vibration transmissibility, mobility, and apparent mass were obtained in frequency range. The results show that rigidity of spine is increased by fixation at lower lumbar, but fixed spine at upper torso has not markedly effects on dynamic responses exposed to the vibration. Find out of this study indicates that using of special design of vehicle seat suspension for people after this surgery is essential.
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Civil Engineering and Environmental Systems, 2009
Density differences may occur because of temperature differentials, suspended sediments, dissolve... more Density differences may occur because of temperature differentials, suspended sediments, dissolved salts or other chemicals. Most of the large surface reservoirs are stably stratified throughout most, or all, of the year. One of the means of assisting the management is to allow a selective withdrawal from the reservoir. And while an intake is used for withdrawal (from the lower layer),
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International Journal of Robotics and Control Systems
The usage of robots has been due to cost reduction and increasing operation accuracy. Furthermore... more The usage of robots has been due to cost reduction and increasing operation accuracy. Furthermore, employing robots in farming can decrease human tasks in hard and dangerous duties such as plowing, spraying pesticides, etc. Spraying chemicals is a common operation in agriculture crop protection. This operation is essential, but it can create some problems such as human and environmental damages by overdosing using pesticides. Recently, researchers focused on precision agriculture to make this smart. Sensors are employed to detect leaves of plants on the ground and spray them as much as required. Thus, pesticide dose will be under control. The current paper aims to introduce a wheeled robot that is developed to detect plants by color sensor and spray them. This robot can move between planting rows and detect weeds based on the leave color. A microcontroller-based board was used as the main controller, which sends spray commands to the sprayer nozzle. Outdoor and indoor tests were car...
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International Journal of Applied Mathematics, Computational Science and Systems Engineering
odays, robots are used instead of labors in dangerous environments for long term by more accuracy... more odays, robots are used instead of labors in dangerous environments for long term by more accuracy. Some of them are made as serial arms and rest of them has parallel, configuration. In design of robot, after main configuration, kinematic and dynamic analysis are main steps. By having them controller design is possible. Also, kinematic inverse and dynamic inverse analysis is essential for main processes. parallel robots are employed widely in many applications due to their properties related to geometry. 5R robot is one of them which is utilized in sorting and engraving. Current paper presents a PI controller for this robot which was designed by coupling SolidWorks and MATLAB software to simulate kinematic of robot. It will be used in medicine injection in next work. Finally, a test rig of robot was fabricated in lab for accuracy assessment. It includes two servomotors which is controlled by Arduino as DAQ. The stability of robot in terms of trajectory control was reach properly.
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Journal of Intelligent Mechanics and Automation
Passenger seat is main part of vehicle which has direct effect on transmitted vibration to the bo... more Passenger seat is main part of vehicle which has direct effect on transmitted vibration to the body. Seat suspension can remove unwanted and harmful vibration if right parameters were selected. Each human body organs has specific natural frequency. When vehicle vibration reaches to this frequency range, resonance will occur, and this phenomenon is harmful in long term. Usually lumped models were used to predict human body response to vibration. In this paper, via Qassem biodynamic model, the relative displacement of lumbar spine seat to spine vibration transmissibility was minimized by artificial neural network method. By this technique, optimal spring constant and damping coefficient were found and verified.
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Papers by Mohammad Gohari