Control of Seat Vibration of a Vehicle Due to Bump on Road

Abstract

This work is focused on the seat suspension system of a vehicle. To control the vibration of the seat suspension in such a way so that it not only safe-guard a rider but also provide high level comfort. With that in mind our first step was to went through work that has been done on the suspension system of vehicle. From that we came to the decision of implementing PID control in the Seat Suspension System to control the acceleration that is produced in the human body due to rough road surfaces. The acceleration is the main factor of discomfort as acceleration creates the jerking effect on the rider’s body. So, we modelled the system using mass, spring and damper. The simulated model was validated with respect to analytical means. After getting satisfactory result from the analytical validation, we transformed the mathematical time domain model into transfer function model for the purpose of controlling. Then, from different studies related to our work we defined the road surfaces and quarter car suspension system. After every system and parameters were defined road surface input, vehicle suspension system and seat suspension system alongside the controller were combined in the MATLAB Simulink to get displacement and acceleration in the human body. Simulation was done for all P, PI, PD and PID control with gain constants acquired by Auto Tuning for a vehicle speed of 3.08 km/h going over a road bump. Now keeping those gain constant same, we changed the speeds of the vehicle over road bumps to see the effect of different control on the system. After analyzing all the data, we found a controller that improves the acceleration effect on the human body which was our ultimate goal. But we needed to find if that controller also works on the random road surface as it works on the road bump. So, again all the subsystems i.e., random road surface, vehicle suspension system and seat suspension alongside controllers were simulated. The output effect on the riders were studied to find results that were satisfactory. From all these we get to know that how P, PI, PD and PID works in seat suspension system of a car when it goes through rough road surfaces and their effect on human body.