# What are practical uses of over-damping? [closed]

We have been given this task of preparing some small research on critical damping and comparing its behaviour and uses with over-damping. I am done with everything else but have been unable to find practical uses of over damping. It'd be great if someone could explain where it's desired.

## closed as off-topic by JMac, Ruslan, ZeroTheHero, John Rennie, Jon CusterAug 22 '17 at 12:34

This question appears to be off-topic. The users who voted to close gave this specific reason:

• "This question appears to be about engineering, which is the application of scientific knowledge to construct a solution to solve a specific problem. As such, it is off topic for this site, which deals with the science, whether theoretical or experimental, of how the natural world works. For more information, see this meta post." – JMac, Ruslan, ZeroTheHero, John Rennie, Jon Custer
If this question can be reworded to fit the rules in the help center, please edit the question.

• – Ruslan Aug 21 '17 at 17:31
• Hello, I have been through this page but I kind of found it to be vague and more of a convo between two people rather than something that I can understand as a newbie. – DmRo912 Aug 21 '17 at 17:35
• This question seems to be more of an engineering question, and potentially doing homework for you. My only hint: What happens in objects where you don't know it's exact characteristics (like mass/stiffness may vary to an extent, such as in a car) and overshoot must be avoided? – JMac Aug 21 '17 at 17:36
• The practical uses are situations where "overshooting" would be a disaster. To repeat the examples in the link, if a plane is landing and controlled by an autopilot, an overshoot which causes the plane to attempt to fly below the level of the runway probably won't end well! The same is true for controlling a machine tool (which is subject to random vibration caused by cutting the material) - if you cut too deep, you end up with scrap metal. Controlling an autonomous vehicle would be another example - you don't want to overshoot when stopping in a confined space for example. – alephzero Aug 22 '17 at 5:10
• @alephzero how about the automatic control of a foundry crucible pouring molten iron! Imagine what overshoot might lead to. – docscience Aug 22 '17 at 22:00

• Every textbook I've seen defines the critical damping factor as $1.0$ (exactly), not $\sim 0.7$. Is $0.7$ an approximation to $1/\sqrt{2}$, in some alternative formulation of the math? Or is it just an empirical number used in some application area (control engineering or whatever)? – alephzero Aug 22 '17 at 5:12