TMSI High Speed Uniformity Machine Presenter: Greg Meine TMSI LLC gmeine@mesnac.us www.tmsi-usa.com
TMSI Introduction Tire Uniformity and DFMS 2
TMSI Introduction Founded in 1991 by Dr. Jerry Potts Headquartered in Akron, Ohio Strong International Presence Advanced Testing Concepts and Engineering Acquired by MESNAC in 2013 3
TMSI Introduction Measurement Systems that provide clear, usable data Control Systems that provide reliable, accurate machine control using simple, intuitive interface for the operator Engineeringthat ties them together, from understanding the testing domain to analyzing the resulting data Innovationfor newer, better, smarter, more cost effective solutions for our customers 4
TMSI Introduction HSU-500 5
TMSI Introduction HSU-500 High precision ball bearings Constant Bearing Pre-load Grease lubrication Low maintenance Thru-spindle Tire Inflation System Spindle Encoder 1024 bit Tooling Expanding collet for street wheels Precision wheel adapters Rolling resistance adapters Laser Runout Probes
TMSI Introduction Tire Uniformity and DFMS 12
Tire Uniformity Perfectly circular tire = uniform Not a perfect world Manufacturing variation Results? Spindle force variation / revolution Conicity and Ply-steer Vehicle Effects: Drift, Pull Ride and Handling characteristics
Non-Uniformity Measurement Roadwheel Load Cell f(t) Spindle/Wheel Assembly
275/40R18 900 lbs/4000 N, 145kph
Harmonic 1
Harmonic 1-5
Harmonic 1-15
Harmonic 1-64
High Speed Uniformity (HSU) Production line uniformity testing is low speed Real world is high speed Cannot diagnose plant/manufacturing problems Develop new and improve existing Tire / Suspension Systems Quantify tire vibrations as inputs to the vehicle suspension system Electric Mobility: NVH very important
First Principle of Measurement Flat frequency response bandwidth of the measurement system must Exceed the bandwidth of interest, else Measurements will be distorted
Measurement System Resonance Linear and logarithmic scales Measured amplitudes skewed from as low as 10% of natural frequency 30% of natural frequency has been used in past
Challenges in HSU Measurements Machine/ Tire dynamics both amplify response Similar frequency range Difficult to tell one from the other If not corrected, distorts data Several attempts have been made to resolve this issue
HSU-1064B High Mechanical Stiffness Spindle Resonance Radial = 450 Hz Fore/Aft = 450 Hz Lateral = 750 Hz 185 Hz first machine resonance TMSI Older Design with substantially higher price tag
Damping Resonances
With increased Damping, comes increased Phase Lag
Why no Damping?? Phase measurement accuracy is doubly important today Definite and indeterminate phase lag with concrete damping Phase lag subject to change over time Usually, more difficult to assess NO back-path correction
Back-path Interference Newton s 3rd Law Equal and opposite forces on the road-wheel Not the case with car driven on road Outside interference Seen by back of the load cell G(t) Load Cell Machine Frame f(t)
Our Solution Dynamic Force Measurement System (DFMS) US patent 6606569 Effective flat bandwidth of 500 Hz, can be extended to 1000 Hz if desired Corrects the back-path Most importantly, NO added damping DFMS produces ZERO phase lag
DFMS Force & Moment Measurement Example in radial direction Newton s 2 nd Law Load cell sees the dynamic force Must be corrected Load Cell w(t ) f(t) F=ma kz-w(t) = mz mz + kz= w(t) kz z= Deflection z = Acceleration m= Mass of Spindle+ Wheel k= Load cell Stiffness
Slip-ring Accelerometer accelerometer cable bundle Instrumented Spindle Kistler Load Cell: m1 Bearing Housing: m2 Bearing Rotor: m3 Bearing Housing: m2 Bearing Rotor: m3
Impulse Input mz + kz= w(t)
Tire Machine FRF s
Running-Tire Data Vertical Direction Fore-Aft Direction D F M S L o a d C e ll O N L Y 1 0 0 0 1 0 0 0 Spindle Force, PSD N^2/Hz 1 0 0 1 0 1 0.1 0 2 0 0 4 0 0 6 0 0 F r e q u e n c y, H Z Spindle Force, PSD N^2/Hz 1 0 0 1 0 1 0.1 0 2 0 0 4 0 0 6 0 0 F re q u e n c y, H Z Effects of machine resonance are significantly reduced Example: Acoustic cavity resonance can clearly be seen
DFMS Advantages Effective way to deal with machine resonant frequencies Flat bandwidths up-to 1000 Hz possible Second station could be added Accurate magnitude and phase angle measurements Simplified machine and load cell Equipped for the future
HSU 500 DFMS OFF KUMHO Ecsta 225/50ZR16
HSU 500 DFMS ON Tire Acoustic Resonance
HSU 500 DFMS On, Zoomed in
Thank You! 23