The MB Dynamics Steering Module Test Simulator (SMTS) is an assembly of components and software designed to facilitate the quiet testing, development, troubleshooting, and auditing of a variety of steering gear and steering column assemblies — collectively referred to as steering modules (including components). The SMTS provides the necessary quiet turnkey elements for performing NVH and rattle testing of a steering module; to reproduce functional or running noises, such as zipper, growl, howl, reversal clunks, howl & growl noises, steering nibble, and other annoying vibration and noises during NVH-related driving maneuvers; to evaluate noises during critical driving conditions, such as high-velocity parking lot maneuvers in tight spaces with large, rapid angle changes at zero vehicle speeds; and to characterize performance during low-frequency (e.g., 0.2 Hz) sinusoids, triangle wave, trapezoid, and CSV position inputs to the steering wheel.
The SMTS helps to evaluate EPS, EPHS, EPAS, MDPS, ColPAS and HPS steering technologies and designs based on their propensity to rattle, plus other NVH and driving-dynamics metrics. The MB equipment applies these steering column angular positions and tie rod excitations using electrodynamic, pneumatic, and/or acoustically-quiet linear and rotary motor technologies. These are direct-drive and therefore do not use gear reducers or other mechanical power transmission elements that can otherwise add to test equipment noise and torque variation.
As SMTS test rigs are non-hydraulic, there is no high-pressure oil, no risks of leaks and maintenance headaches, no negative environmental impact, and much lower equipment noise levels. While not a durability rig, the SMTS may be used to condition or wear a steering module to varying stages of useful life within SMTS equipment limits.
MB’s Test Engineering Services have been found useful to develop steering-specific test procedures and test processes, to perform test planning and results evaluation, for accelerated learning of the technology, and for data acquisition and analysis.
Applications & Test Jobs-to-Be-Done
OEMs and suppliers of steering systems and components have many rattle, NVH, functional, and performance tests to perform during design, development, test and evaluation. MB’s mission is to innovate and deliver quiet test technologies to help address these applications and jobs that test and development engineers need to do, including:
- Test for annoying rattle and running noises due to road-excited stimuli and customer-actuated driving maneuvers to diagnose & fix root causes
- Apply full range of forces (static and dynamic) over full range of tie rod end positions (any position between lock to lock, nominally 200mm p-p) and over full range of tie rod angular positions: jounce, rebound, fore, aft
- Condition or wear gears and other components in the lab to accumulate accelerated customer-equivalent kilometers (life cycle assessment), then assess rattle and NVH performance on the same test equipment
- Use various static & dynamic loads from the wheel/tire/road interface (measured on tie rod loads) and applied by Rack Load Simulator in combination with steering wheel positions and driving maneuvers applied by Driver Simulator to assess steering and EPS performance
- Use physical tests to validate and correlate math models and model-based development of electric control system performance algorithms
- Quietly produce accurate, controlled, repeatable inputs to the in-vehicle steering wheel to enable acquisition of acoustic data and wheel motions during zero-vehicle-speed and simulated parking maneuvers to characterize in-vehicle zipper & other steering noises
- Evaluate effect on warranty costs & customer satisfaction of EPS algorithms that neutralize and cancel driver-perceived wheel oscillations due to wheel and rotor imbalance and other driving conditions over prolonged periods
- Evaluate stick-slip, lash, torsional stiffness, and hysteresis performance characteristics of I-shafts, inner tie rods, columns, couplings/isolators and combinations under environmental, wear and various boundary conditions
- Discriminate between steering technologies and supplier offerings, based on their propensity to rattle, cause other annoying noises, plus other driving-dynamics metrics
- Benchmark competitor steering gears, I-shafts, columns, etc.
- Fulfill the following steering test procedures: GMW16216, GMW17112, GMW14479, GMW17207, GMW15599, GMW17422, Ford CETP 01.01-L-407, Ford CETP 11.04-E-400, Ford ESECPC-3C529-A4 III.B.1.5, Ford ESECPC-3C529-A4 III.B.3.1, Ford ESECPC-3C529-A4 III.C.1.6, Ford ESECPC-3C529-A4 III.C.1.8, Ford Engr Spec III.C.1.13, and Ford ESAE5C-3280-AA