Test system supplier AB Dynamics has launched a new axle level NVH rig – the ANVH 250 – following demand from vehicle manufacturers to ascertain NVH issues earlier in the design process and over a greater operating range.
“The ANVH 250 enables manufacturers to measure and optimize the NVH characteristics of suspension systems during the vehicle design process, helping to produce a cost-effective suspension design that delivers high levels of cabin refinement,” explained Edward Haynes, chief engineer – electric actuators, at AB Dynamics.
“The ability to assess the suspension at the early design stage over such a large frequency range helps avoid expensive NVH fixes at later stages of a vehicle program. This reduces overall vehicle cost and accelerates product time-to-market.”
The ANVH 250 measures NVH transmission from wheel hubs, through suspension components, to the suspension mounting points. It also measures the transmission of vibration up to 250Hz, from the suspension springs, dampers, linkages, anti-roll bars, and elastomeric bushes.
Its design features an exceptionally stiff frame design in combination with AB Dynamics’ unique high frequency linear actuators, specifically designed for this application. The direct-acting electric linear actuators deliver motion over a frequency, displacement and load range not achievable with any available hydraulic actuator. They are also inherently safer than hydraulics because there is less stored energy in the system.
With an axle installed, two sets of three actuators apply precise motion to each hub at frequencies from 0-250Hz and displacements from +/-0.01 to +/-50mm, while tri-axial load cells measure the forces transmitted to each vehicle attachment point. The ANVH 250 can apply a range of sinusoidal, random input and road load data displacements to the axle system. Displacements can be applied to the wheel hubs in pairs or individually in the vertical (Z), longitudinal (X) or lateral (Y) directions. The paired displacements at the hubs can be in phase or in anti-phase.
A graphical user interface enables the operator to navigate between different parts of the system to control the machine and configure the test procedure. All test data, system configuration and instrumentation settings are stored in a search relational database system. Key axle data is entered via the interface screen. The ANVH 250 is supplied with ANVH Grapher, a screen-plotting program that enables results to be viewed as soon as a test is completed so the user can check the test has run successfully.
The rig is suitable for evaluating the majority of passenger and light commercial vehicles. As an option, it can be supplied with AB Dynamics’ Dynamic Arm Wheel Position Measurement System (WPMS) for measurement of the wheel hub motion in six degrees-of-freedom.