NVH optimisation of an electromechanical brake-actuator gearbox

The question

An electromechanical brake caliper drives its piston through a compact gear train. For a new caliper variant, the supplier wanted to predict and reduce gearbox noise early, instead of finding it on late prototypes, and to give its own engineers a method they could repeat.

What the customer received

• Validated RFM model and Simulink co-simulation set-up
• Before-and-after report: transmission error, excitation forces, ERP and sound pressure
• Annotated CAD recommendations for the housing
• Methodology manual and training for the technical team

Services: NVH and multibody simulation, Testing and model correlation, Design methods and validated models

What we did

1. Built a reduced flexible multibody (RFM) model in RecurDyn with gears, bearings, flexible housing and caliper.
2. Co-simulated it with the customer’s Simulink actuator control, for two control strategies.
3. Mapped modes and excitation orders with FEM modal analysis and a Campbell diagram including the motor orders.
4. Optimised gear macro- and microgeometry in KISSsys for transmission error and excitation forces, and derived housing changes from modal strain energy and equivalent radiated power.
5. Correlated accelerations, FFT spectra and surface velocities with measurements on hardware.