Methods and procedures in order to measure the wear/aging in automotive shock absorbers in real time on the vehicle. This would be necessary to implement a degradation compensation control of the damper. What values and parameters can be used for this aim.
For measuring in real time, I would expect you'd want two of those accelerometers that Bert mentions above. One where the shock absorber connects to the chassis, and the other where it connects to the spring.
Then, in a controlled setting, you measure the relationship between these two accelerometer readings, in a series of scenarios, from slow to violent changes in acceleration of the sprung mass, when the suspension is tuned as it should be. As shock absorbers wear, you should notice a greater difference between the two accelerometer readings, in just about all of those points where the motion difference was plotted.
I guess, optimally, close to critically damped is what you're striving for? Not sure what the best answer is there. If the shock absorbers are too strong, the suspension becomes overdamped, and you will encounter situations in which the springs become more and more compressed. So in rough terrain, you end up with less and less wheel travel, which is hardly what you want to be the case.
And underdamped makes the passengers sea-sick, also not ideal! Never mind the car would become hard to control.
place an accelerometer on the unsprung portion of the shock absorber. Changes in the acceleration curve will show changes in the damping behaviour of the shock absorber.
For measuring in real time, I would expect you'd want two of those accelerometers that Bert mentions above. One where the shock absorber connects to the chassis, and the other where it connects to the spring.
Then, in a controlled setting, you measure the relationship between these two accelerometer readings, in a series of scenarios, from slow to violent changes in acceleration of the sprung mass, when the suspension is tuned as it should be. As shock absorbers wear, you should notice a greater difference between the two accelerometer readings, in just about all of those points where the motion difference was plotted.
I guess, optimally, close to critically damped is what you're striving for? Not sure what the best answer is there. If the shock absorbers are too strong, the suspension becomes overdamped, and you will encounter situations in which the springs become more and more compressed. So in rough terrain, you end up with less and less wheel travel, which is hardly what you want to be the case.
And underdamped makes the passengers sea-sick, also not ideal! Never mind the car would become hard to control.
Accelerometer doesn't help to monitor the damper in real time.
For real time performance monitoring, load cell and displacement sensors needs to be mounted to measure real time force, displacement and velocity. Any deviation in the force-displ and force-velocity diagram will indicate the wear/aging.
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