Ride comfort enhancement for passenger vehicles using the structure-immittance approach

Abstract

This paper investigates the ride comfort enhancement potential for passenger vehicles by employing inerter-spring-damping suspension struts. The inerter has been used on Formula 1 racing cars and several beneficial devices incorporating inerters have also been identified for ride comfort enhancement. However, previous investigations either were limited to simple network configurations with moderate performance improvement, or resulted in complicated configurations with a large number of elements which are impractical for real-life applications. In addition, some important practical performance constraints have not been taken into consideration, such as high-frequency dynamic stiffness which influences the NVH performance, and frequency content consideration of the sprung mass acceleration which more directly relates to passenger perception. In this paper, a quarter-car model including top mount is studied, with the performance of a conventional suspension strut presented as baseline. The structure-immittance approach, which can cover all networks with predetermined numbers of each element type is adopted for identifying the optimal suspension configurations. Several configurations with up to a 13.3% performance improvement are identified with other practical performance indices to be no worse than the baseline. The suspension configurations proposed in previous works are also considered for a sake of comparison, demonstrating significant advantages of the structure-immittance approach. Subsequently, a sensitivity analysis against the sprung and unsprung mass changes is carried out, which represents cargo and tyre weight variations, respectively. Time domain response and other reality checks are then conducted for the out-performing configurations, which reconfirm the ride comfort enhancement and ensure no unexpected behaviour occurs.

Using an inerter to enhance an active-passive-combined vehicle suspension system

“…is the power spectra density (PSD) of the road velocity, as detailed in [16,37]. Note that the road velocity and displacement PSDs are transformable, and both can be used as the exotic excitation.…”

“…Note that the road velocity and displacement PSDs are transformable, and both can be used as the exotic excitation. The velocity PSD is selected for derivation here (also in [16]) because it is constant regardless of the frequency, which can simplify the theoretical derivation. In this study, we select V = 25 m/s and κ = 5×10 -7 m 3 /cycle, in line with [37].…”

“…All the dynamic performance and control requirements have been expressed in the form of H 2 norm which will now be analytically calculated using the Lyapunov equation. An analytical expression of a stable transfer function H(s) in the H 2 -norm form can be computed from a minimal state-space realization (16) where the matrix L is the unique solution of the following Lyapunov equation…”

“…It completes the electrical and mechanical analogy and enables all the positive-real admittances to be realized passively. Since its introduction, many inerter-based layouts with low complexity have been proposed [12][13][14][15] and potential improvements across a wide range of application areas have been identified, such as automobiles [16], railway vehicles [17,18], wind turbines [19], landing gear [20] and civil engineering [21,22].…”

Enhancing pantograph-catenary dynamic performance using an inertance-integrated damping system

“…With the introduction of the inerter, all positive-real immittance functions can be realised by passive networks consisting of inerters, dampers and springs. Performance benefits from employing inerters have been identified for various mechanical systems, including motorcycle steering systems [32], passenger vehicle suspensions [33,34], train suspensions [35][36][37], buildings [38][39][40], landing gear [41], wind turbines [42] and cables [43].…”