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

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%.MethodologyAt 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 DiscussionIn this section, a comparison between passive suspension and all the control methods has been performed in time and frequency domains. ConclusionA 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.