Design and Development of a Semi Active Electromagnetic Suspension System

This research paper includes the design and development of semi active suspension system using the permanent magnet, electromagnet and its control. The combination of permanent magnets is used to withstand static load of 20 kg. The controller is used to deploy the control logic and decide the supply of the required quantity of current to the electromagnets. There are two inputs given to the controller, one of them is air gap between upper magnets and lower magnets and second is the nature of the road profile in terms of amplitude of irregularity of the road. Based on the values of these two inputs the current supplied to the electromagnet is varied which results in variable damping force. The experimental setup for semi active suspension is developed. It includes a metallic roller fitted with irregularity similar to road profile, chain and sprocket connected to electric motor, whose magnitude is sensed and given as an input to the controller. Based on this input value, the current supplied is varied as per the predefined look-up table in the control module. The experiments are conducted at different speeds resulting in frequencies of up to 2.5 Hz and road uneven surface of amplitude at least 10 mm. The response of the damper is observed using the linear potentiometer detecting the difference in motion of lower and upper magnets of the setup. The experimental results show that a semi active suspension system with proper selection and combination of number of permanent magnets and electromagnets can be designed for damping the vibrations for lower frequency up to 2.5Hz and static load applications of up to 20 kg.