Ride and Comfort Measurements - A Challenge of Subjective and Objective Correlation 2021-26-0445

Traditionally, vehicle ride and comfort is evaluated, subjectively as well as objectively. Based on the outcome of subjective and objective tests, it is refined by optimizing primary suspension system, secondary suspension system, seating system, rubber bushings, frame and BIW for mass, stiffness, damping, geometry etc. Many a time subjective assessment results stands in contradiction to the objective assessment results; emphasizing need for having good correlation between subjective and objective test results. In such cases, it is ambiguous to decide suitable design refinement action and can lead to no improvement situation. Hence, it is essential to have concurring test procedures for subjective and objective ride evaluation. This paper describes a novel methodology to address the above said challenge. There are defined set of test events and measurement data points to be used in subjective and objective testing. The subjective assessment is performed using clearly defined goals for what to look for and how to look for different ride and comfort attributes and sub attributes. Similarly for objective test, accelerations, displacements and loads are measured at defined locations on vehicle application specific, various types of service roads for long enough duration, to have no or minimum impact of road inputs or events having high kurtosis value, on the objective ride measurement results. Measured data is post processed separately to arrive at objective ride index value for each of the subjective attribute i.e. bounce, pitch, roll, head toss, bobbing, choppy ride etc… For this, set of measured data is processed and analyzed for interested and relevant frequency ranges instead of limiting it to ISO 2631. This approach provides direct comparison of subjective rating number and objective ride index value for each of the attribute. This new approach has proven very useful in refining the vehicle ride and comfort by achieving 85~90% correlation between subjective and objective test results.