Suspension Component Test Systems

Acoustic quality, vehicle dynamics and stability, and driver comfort play an increasingly important role in the development of new chassis and suspension systems – both passive and active. Noises in suspension components can cause customer dissatisfaction and lead to high warranty costs and are difficult to diagnose especially on historically-used, noisy hydraulic test rigs. The MB Suspension Component Test Rig (SCTR) enables dynamic simulation of real road excitations and synthesized waveforms, performing industry-standard Force-Velocity and Force-Displacement tests and low speed friction tests, and assessing other NVH and structure-borne noises for comprehensive performance characterization and sound and vibration analyses on a wide variety of chassis components.

Our innovative technology uses a combination of dynamic force generation using acoustically-quiet linear motors combined with quiet, no-stick-slip air bearings for motion creation – augmented by air springs for compression and curb-height loading. High-frequency closed-loop control of the dynamic response of servo-motor acceleration/force systems presents unique challenges. MB’s past work with dynamic control of servo-motors has shown that the classic servo-motor control systems, using position encoder feedback for displacement control, are unsuitable for use where high-frequency controlled dynamic acceleration/force response is also required. This is because a position encoder cannot deliver the resolution required to control high-frequency road load data with up to 50Hz content. This problem is especially acute above 20 Hz. Other strut/shock tests require even higher frequency content. MB has developed a hybrid control system using both position encoder and accelerometer / force feedback to achieve accurate high-frequency dynamic response. This control strategy is proven technology and is employed in the SCTR rig.

Suspension Component Test Rig Data Sheet: Download PDF
Airbag Sensor Test System (MB ABSTS) Data Sheet: Download PDF

Noise Characterization, NVH, & Performance Characterization
  • Strut Pop
  • Rebound Noise
  • Sway Bar & Bushing Noise
  • Leaf Spring Noise
  • Noises in Active Dampers and Mounts
  • Stick/Slip and Squeak Noise
  • Road Load/Time History Replication
  • Force/Displacement
  • Force/Velocity
Specifications
  • Peak Dynamic Force (100% of theoretical motor rating): >17kN Pk Instantaneous (uncooled)
  • Peak Dynamic Force (de-rate for reasonable operation): >14kN Pk Instantaneous (uncooled)
  • Continuous Static Force: >4kN Pk Sine Test
  • Static Support Force (Air Spring Actuator): >8kN Continuous
  • Peak Velocity (no payload): 4m/s
  • Peak Velocity (10kg payload): 4m/s
  • Linear Motor Actuator: acoustically quiet, high-fidelity dynamic waveforms
  • Air Spring Actuator: high compressive force, more durable than air cylinder
  • Quiet: test equipment does not mask test item noises
  • Background Noise: <2.0 Sones or 35dBA, 13Hz 1.0g pk 3mm p-p sine motion, no test item mounted
  • No Hydraulics: safe, no high pressure oil, no environmental issues
  • Low maintenance: no seals, servo-valves, hoses to replace
  • Air Bearings: friction-less motion, non-contacting, no wear, no striction, no balls or rollers, low noise
  • Control Modes: acceleration, displacement, force (static and dynamic); road load time history, PSD random, sine, triangle, square, synthesized waveforms
  • Time History Force Accuracy: typically <5%, Response vs. Target
  • Displacement: 205mm p-p between stops
  • Control Frequency Response: DC-100Hz, rolls off to 200Hz
  • Encoder: Resolution, 1×10(6) pules/mm 1V p-p Sine/Cosine analog, incremental
  • Load Cell: interface Model 1010, 12.5kN or 25kN, tension & compression, shunt calibration, eccentric load compensation, performance to 0.03%, safe overload, (+/-)300%(option)
  • Analog signals available: acceleration, velocity, displacement, force, motor current proportional to dynamic force
  • Motor-controlled height adjustable crosshead
  • Hinged safety guard (Lexan) around test item for see-through viewing
  • Dimensions: 1.56m x 1.56m x 2.91m (Safety guard)
  • Max test item height: 1000mm
  • Test space width between columns: 1050mm
  • E-STOP: at Rig and at operator console