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# Motion-Laws for Segments

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# Motion-Laws for Segments

## Motion-Laws - also called Cam-Laws.

Select the Motion-Law for each segment with the Motion-Law Selector or the Segment-Editor.

Each Motion-Law is a mathematical expression that defines how an output variable changes as a function of an input variable.

The mathematical expressions evaluate exactly the displacement, velocity, acceleration, and jerk motion-values. You do not need to know any mathematics.

For convenience, we can separate the motion-laws into three groups.

Note: We list the motion-laws for you in the Motion-Law Selector alphabetically (English spelling).

 The Traditional Motion-Laws (also named Standard Motion-Laws) have been used for many years in cam mechanisms for motions that have Rise and Return segments. The Traditional Motion-Laws are based on: •Trigonometric Functions, and/or •Polynomials Functions Traditional Motion-Laws: 1.Constant-Acceleration & Deceleration - Polynomial Function 2.- Polynomial Function 3.- Polynomial Function 4.Trigonometric Function 5.Cycloidal Constant-Velocity 50% -Trigonometric Function 6.- Polynomial Function 7.Trigonometric Functions 8.Trigonometric Functions 9.- Polynomial Function 10.- Polynomial Function 11.- Polynomial Function 12.Polynomial Low Impact Crossover - construct with two Flexible-Polynomial segments 13.- Polynomial Function 14.Ramp - Trigonometric Function 15.Trigonometric Functions 16.Sine-Constant-Cosine Acceleration + SCCA with Constant-Velocity 20%, 33%, 50%, 66%.... - Trigonometric Functions 17.Trigonometric Functions 18.Trigonometric Functions 19.Trigonometric Functions You can edit the Segment Parameters in the Segment Editor to get a motion-law similar to: 20.Flexible Polynomial - it can be used for different motion-laws - see also Special Motion-Laws Flexible-Polynomial, below. Throw: a motion-law is a rise segment followed immediately by a return segment. You must design these different Throw motion-laws with two Flexible Polynomial segments. They have different continuity, and shape as they rise and return from the maximum displacement. Low Impact at Crossover uses two Flexible-Polynomial segments to give one Rise motion-law. The Jerk is zero when the Acceleration changes to Deceleration.

### Special Motion-Laws

 These meet the needs of specific applications. 25.Y–Inverse-Sinusoid : when applied to the motion of a crank, it gives a constant linear velocity at the tip of a crank. Maximum of one Y-Inverse-Sinusoid segment per crank rotation. 26.CV Inverse Crank : similar to the Y-Inverse-Sinusoid, Not limited to one Crank-Constant-Velocity segment per motion. 27.Flexible-Polynomial - a VERY important and useful motion-law - see also Motion-Laws 20 - 24 28.Ramp - also a useful motion-law - see also Motion-Law 5, Cycloidal CV50

### List Segment-Types

 You can import your own motion-values to a List Segment-Type: 31.Z-Raw-Data

#### When to use the Flexible Polynomial OR a Traditional, or the both Motion-Laws?

Flexible-Polynomial is the default motion-law. It is very powerful. We recommend that you learn how to use it effectively and efficiently.

We recommend that you use:

All Flexible-Polynomials - to give powerful and flexible motion-design possibilities

or

All Traditional Motion-Laws - usually the easiest to design a Rise and Return type motion.

or

A mixture of Flexible-Polynomial and Traditional Motion-Laws - most difficult motion-design but may have advantages

 The Motion-Laws available in MotionDesigner exceed the German Technical VDI-guidelines 2143 Papers (Part) 1 and 2. Also bear in mind, that a motion at a cam-follower or servomotor is usually found by MechDesigner with Inverse-Kinematics. When this is the case, the motion at the cam-follower or servomotor is not the same as the motion-design that is given to the tooling, or Motion-Part.