docs: Reword smoothed look-ahead description in Kinematics

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

1 files changed, 14 insertions, 11 deletions

diff --git a/docs/Kinematics.md b/docs/Kinematics.md
index 0a0670f8..4787ebf8 100644
--- a/docs/Kinematics.md
+++ b/docs/Kinematics.md
@@ -101,7 +101,7 @@ Smoothed look-ahead
 -------------------
 
 Klipper also implements a mechanism for smoothing out the motions of
-short "zig-zag" moves.  Consider the following moves:
+short "zigzag" moves.  Consider the following moves:
 
 ![zigzag](img/zigzag.svg.png)
 
@@ -109,20 +109,23 @@ In the above, the frequent changes from acceleration to deceleration
 can cause the machine to vibrate which causes stress on the machine
 and increases the noise.  To reduce this, Klipper tracks both regular
 move acceleration as well as a virtual "acceleration to deceleration"
-rate.  Using this system, the top speed of these short "zig zag" moves
+rate.  Using this system, the top speed of these short "zigzag" moves
 are limited to smooth out the printer motion:
 
 ![smoothed](img/smoothed.svg.png)
 
-In the above, note the dashed gray lines - this is a graphical
-representation of the "pseudo acceleration".  Where the two dashed
-lines meet enforces a limit on the move's top speed.  For most moves
-the limit will be at or above the move's existing limits and no change
-in behavior is induced. However, for short "zig-zag" moves the limit
-comes into play and it reduces the top speed. Note that the grey lines
-represent a pseudo-acceleration to limit top speed only - the move
-continues to use it's normal acceleration scheme up to its adjusted
-top-speed.
+Specifically, the code calculates what the velocity of each move would
+be if it were limited to this virtual "acceleration to deceleration"
+rate (half the normal acceleration rate by default). In the above
+picture the dashed gray lines represent this virtual acceleration rate
+for the first move. If a move can not reach its full cruising speed
+using this virtual acceleration rate then its top speed is reduced to
+the maximum speed it could obtain at this virtual acceleration
+rate. For most moves the limit will be at or above the move's existing
+limits and no change in behavior is induced. For short zigzag moves,
+however, this limit reduces the top speed. Note that it does not
+change the actual acceleration within the move - the move continues to
+use the normal acceleration scheme up to its adjusted top-speed.
 
 Generating steps
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