Motion-Laws [also called 'Cam-Laws'].
A Motion-Law defines, with a mathematical expression, how an output variable changes as a function of an input variable. The output variable is either a linear [m, cm, mm, inch] or an angular [degrees, radians] value. The input variable is usually machine-angle [ degrees, radians, cycles] or time [ msecs, seconds].
The mathematical expression is defined as a displacement, velocity or acceleration function.
The mathematical expression is differentiated or integrated to obtain displacement, velocity, acceleration and jerk. The calculus does not use 'numerical' techniques. Rather, we solve the equations for each motion-derivative to give the motion-values for each motion-derivative exactly.
We list the Motion-Laws alphabetically [English] in the Motion-Law Selector.
We can separate the motion-laws into three broad groups.
Traditional Motion-Laws are those that have been used for many years as 'Rise' or 'Return' segments, usually between two Dwell Segments.
The Traditional Motion-Laws' are based on function that are:
|•||Trigonometric / Harmonic|
In English alphabetical order, the Traditional Motion-Laws are:
|3.||Cubic - Polynomial Function|
|5.||Dwell - Polynomial Function|
|13.||Ramp - Trigonometric Function|
|15.||Sine-Constant-Cosine + SCCA with Constant-Velocity 20%, 33%, 50%, 66%.... - Trigonometric Function|
Also, use the 'Triple Harmonic' Controls in the Segment-Editor to give:
Throw Motion Laws*
Construct a 'Throw' motion with two Flexible Polynomial segments. The two segments can be thought to be a Rise and Return motion, without a Dwell segment between them.
The motion is named 'Throw' because it is similar to the vertical motion of a ball when it is 'thrown' up in the air. For convenience, they are called 'Quick-Return'. However they are actually a 'quick-transition' from the Rise segment to the Return segment.
The of motion 26 is high compared to the other motion laws. This means that backlash is traversed quickly to give a large velocity impact.
Asymmetrical Throw Motion
We construct the Throw motion-laws with two segments. Thus, they do not need to have the same duration, nor actually the same displacement.
These meet the needs of specific applications.
When you select these 'Motion-Law', you can import your own motion-values.
The Z-Raw-Data is the easiest to use, as it imports your data values directly.
The Position-List scales all of the values you import. The scale is in proportion to the difference between the start and end positions that you specify with the Blend-Point Editor - it is used to compatible with Camlinks.
'Flexible Polynomial' OR 'Traditional' Motion-Laws?
The Flexible Polynomial is the 'default' motion-law. We strongly recommend you learn how to use it effectively and efficiently. It is very powerful.
Traditional Motion-Laws have advantages in some circumstances, especially for simple Rise-Dwell-Return motions.
Thus, we recommend, make the segments:
|•||All Flexible-Polynomials - most powerful and flexible motion design possibilities|
- or -
|•||All Traditional Motion-Laws - 'standard' motion-design requirements|
- or -
|•||A mixture of Flexible-Polynomial and Traditional Motion-Laws - least preferred.|
The Motion-Laws available in MotionDesigner exceed the German Technical VDI-guidelines 2143 Papers (Part) 1 and 2. Also bare in mind, that the motion at a cam-follower or servomotor is usually found by MechDesigner with Inverse-Kinematics. In this case, the motion at the cam-follower or servomotor will not be the same as the motion of the Motion-Part.