How to make a smooth animation without changing the speed?

I tried different settings, but I haven’t received the desired result.
Either the animation is smooth but first it slow then speeds up and then slows down at the end (Bezier) or animation rude but it has one speed (Linear).
Example: http://i.stack.imgur.com/4FxWY.gif
Is there a way to make the animation smooth and have it play with one speed without acceleration & deceleration?

The image above is the simplest way to visualize what i mean, but the image in [this link shows the kind of objects i’m animating: http://f-picture.net/lfp/s019.radikal.ru/i618/1506/6f/cd298ba1bb1e.gif/htm, and it behaves quite abrupt when Linear, but Bezier gives pronounced easing in-out.

Go to the graph editor and adjust the animation curves to exactly the effect you want https://www.blender.org/manual/animation/editors/graph/fcurves.html
Try some of the other interpolation and easing modes (shortcut T)

I tried all these variants but I didn’t found need result.

Animation takes practice. Most of the time you need to play with the keys in the graph editor. Mainly you do this when you are polishing the animation though.

I agree with RadDavis, it takes practice and you need to play with the keys!
Usually, to get what they want, animators would turn their keys into Bezier and play with the handles, sometimes even breaking the curves.

Is there a way to make the animation smooth and have it play with one speed without acceleration & deceleration?

What you want to do isn’t possible, because to smooth an animation you need some kind of acceleration & deceleration, now it doesn’t have to be much. but linear keys would give you something VERY robotic. Some anticipation and some reaction would help too!

Hope it helps!

Mathias.