نوع مقاله : مقاله پژوهشی

نویسندگان

• منا طهماسبی ¹
• محمد گهری ²
• محمد مبارک آبادی ³

¹ استادیار پژوهشی، بخش تحقیقات فنی و مهندسی کشاورزی، مرکز تحقیقات و آموزش کشاورزی و منابع طبیعی استان مرکزی، سازمان تحقیقات، آموزش و ترویج کشاورزی، اراک، ایران

² استادیار، گروه طراحی جامدات، دانشکده مهندسی مکانیک، دانشگاه صنعتی اراک، اراک، ایران

³ دانشجوی کارشناسی ارشد، گروه طراحی جامدات، دانشکده مهندسی مکانیک، دانشگاه صنعتی اراک، اراک، ایران

چکیده

ارتعاشات انتقال‏یافته به بدن راننده در خودروهای غیر‏جاده‏ای سنگین که سیستم تعلیق اولیه ندارند باعث ایجاد مشکلات سلامتی در بلند مدت می‏گردد. معمولا در این‏گونه از وسایل‏نقلیه سیستم تعلیق ثانویه در صندلی راننده تعبیه می‏شود تا بتواند جداسازی ارتعاشی و جذب آن را انجام دهد و باعث جلوگیری از مشکلات سلامتی بخصوص در ستون فقرات شود. سیستم تعلیق غیرفعال صندلی به طور گسترده برای این منظور استفاده می‏شود، اما کارایی آنها پایین است. سیستم تعلیق صندلی فعال و سیستم تعلیق نیمه‏فعال عملکرد بهتری در جلوگیری از نوسانات ناخواسته دارند. یکی از میراگرهایی که اخیرا مورد توجه محققان قرار گرفته است میراگر نیمه‏فعال مجهز به سیال هوشمند مگنتورئولوژیک است که با ایجاد میدان مغناطیس گرانروی سیال تغییر می‏کند. بدین‏ترتیب سیستم تعلیق با استفاده کمی از جریان الکتریسیته می‏تواند با تغییر ضریب میرایی به‏صورت موثری انرژی ارتعاشی را مستهلک کند. در مقاله حاضر یک کنترل‏گر جدید هوشمند فعال نیرو مجهز به تخمین‏گر یادگیری تدریجی طراحی و شبیه‏سازی شده است. سیستم تعلیق به مدل ارتعاش بدن انسان کوپل شد و نتایج ارتعاش بدن راننده بدست آمد. نکته قابل توجه این است که کنترل فعال نیرو می‏تواند برای حذف اغتشاشات سرعت بالا نیز بکار رود. از آنجایی‏که ارتعاشات رخ داده در خودرو دارای سرعت تغییرات بالا هستند نتایج نشان داد که کنترل فعال نیرو مجهز به سامانه تخمین‏گر یادگیری تدریجی می‏تواند بطور موثری در کاهش ارتعاش انتقالی به راننده عمل کند بطوری‏که پیک‏های اول و دوم ارتعاش در حدود 60 درصد کاهش داشتند.

کلیدواژه‌ها

• کنترل گر فعال نیرو
• میراگر مگنتورئولوژیک
• سیال هوشمند
• الگوریتم یادگیری تدریجی
• خودروی سنگین غیر‏جاده ای

عنوان مقاله [English]

Design of Active Force Controller for Off-Road Seat Suspension equipped to MR Damper

نویسندگان [English]

• Mona Tahmasebi ¹
• mohammad gohari ²
• mohammad mobarakabadi ³

¹ Agricultural Engineering Research Department, Markazi Agricultural and Natural Resources Research and Education Center, Agricultural Research, Education and Extension, Organization (AREEO), Arak, Iran

² Department of Mechanical Engineering, Arak University of Technology, Arak, Iran

³ Department of Mechanical Engineering, Arak University of Technology, Arak, Iran

چکیده [English]

Transmitted vibration to driver body (whole-body vibration) in heavy-duty Off-road vehicles without primary suspension leads to health problems in long term such as spine disorder, back pain, heart abnormal beating, vision disable, digestive problem, etc. Commonly, secondary seat suspension is used to isolate vibration and remove health problems, s especially in the spinal column. Passive seat suspension is widely employed for this purpose, but its efficiency is low. Active seat suspension and semi-active suspensions have better performance in blocking unwanted oscillation. Recently, semi-active magnetorheological dampers are focused on by researchers which can adjust their viscosity by electromagnetic flux. It is called smart fluid due to having controllable parameters such as damping ratio by electricity variations. Thus, suspension can dampen oscillation by low electricity current efficiently. The current paper introduces a novel active force control (AFC) equipped with an iterative learning estimator for seat suspension via MR damper. Results of simulations show that it can cancel vibration perfectly. The suspension was coupled to the human body vibration model, and the driver vibration results have been obtained. It is important to note that active force control can also be used to eliminate high-velocity disturbances. Since the vibrations that occur in the car have a high rate of change, the results indicated that active force control equipped with an iterative learning estimator system can be effective in reducing the transmission vibration to the driver so that the first and second vibration peaks was reduced by about 60%.

Methodology
At the first, a dynamic model of an off-road vehicle seat suspension which is equipped with an MR damper has been developed. After that, a PID controller has been designed for semi-active seat suspension. Next, the PID controller has been integrated into the AFC method. Lastly, utilizing the ILA in mass estimation for the AFC approach and simulation results of that has been discussed.
The simulation work has been developed employing MATLAB/Simulink software whereas passive suspension and semi-active suspension via the PID and AFCAIL controllers were simulated. To evaluate the performance of the control schemes, the seat suspension model was exposed to a number of various disturbances as road roughness listed as follows:
Results and Discussion
In this section, a comparison between passive suspension and all the control methods has been performed in time and frequency domains.
Conclusion

A novel controller called the active force control has been employed for vibration control of seat suspension equipped by a magnetorheological (MR) damper. The AFC method was integrated into the iterative learning algorithm to calculate the estimated mass of the system named AFC-IL . The designed controllers were simulated for the vibration canceling of an off-road vehicle seat suspension system. The AFC technique achieved to be uncomplicated in terms of calculation and change it suitable for real-time working conditions. Moreover, the AFC demonstrates high performance and produce robust and accurate response still in the presence of various disturbances. The simulation results express that for known parameters and situations, the proposed AFC-IL method efficiency enhanced in comparison to the popular PID controller. The results exemplify that the AFC-based scheme as an intelligent control technique has proper potential to eliminate the disturbances superiorly for the off-road vehicle seat suspension. Although complementary efforts should be accomplished to investigate the influences of other types of disturbances, parameters and uncertainties changes in real situations such as road trials. In continuing a test rig will be developed to evaluate the AFC scheme performance in real conditions in terms of the vibration attenuating and optimized parameters.

کلیدواژه‌ها [English]

• Active Force control
• Magnetorheological Damper
• Smart Fluid
• Iterative Learning Algorithm
• Heavy Duty Off-Road Vehicle