﻿ Tutorial 16: Motion-Path FB and Blend-Curves

# Tutorial 16: Motion-Path and Blend-Curves

## Motion-Path and Blend-Curve

### The Objective

 • Add and edit a Blend-Curve
 • Add and edit a Motion-Path FB
 • Learn about motion continuity and curvature continuity
 • Apply the Motion-Path FB and Blend-Curve to the Pick & Place motion of a two degrees-of-freedom SCARA type robot.

### Motion Properties of a Point that moves on the XY-Plane [Mechanism-Plane].

If we make a Point move with a general motion on the Mechanism-Plane, we can think of its:

 A. Path on the Plane
 B. Motion magnitude [velocity and acceleration] along the path

In MechDesigner, to define the motion of a Point on the Mechanism-Plane, you can use:

Piggyback Sliders : where we give a motion to each slider so that the Slider that is 'on the back' of the other gives the path and the motion.

Motion-Path FB : where we pre-define a sketch-path and give the motion of a Point along the Path.

Some design problems are easier to do with Piggyback Sliders and others with a Motion-Path FB.

### Summary of Procedures: 'Piggyback Sliders' and 'Motion-Path FB'

#### Piggyback Sliders

 1 Use MotionDesigner to design two separate motions for the X–axis and Y–axis.
 2 Add the 'X–Slider'. Make this move in the X–axis direction of the model.
 3 Add the 'Y–Slider'. Add this to the Y–axis of the 'X–Slider' so that its Y–axis direction of the model.

Note: The Slider directions are usually in the X–axis and Y–axis directions. However, this is not necessary. Put the direction of each slider to suit your design requirements.

Motion Properties of Piggyback Sliders:

 A. The shape of the Path is a combination of the separate X–axis and Y–axis motions.

To show the path, add a Trace-Point to a Point on the Y–Slider - the slider being given a piggyback.

 B. The magnitude of the motion is a combination of the X–axis and Y–axis motions.

The motions in the X–axis and Y–axis are known directly from the motions given to the Sliders, as designed in MotionDesigner.

You can measure the Magnitude, X–axis and Y–axis motions with a Point-Data FB.

#### Motion-Path FB

 1 Define the shape of a path, explicitly, with sketch-elements.
 2 Add a Motion-Point to the path, with the Motion-Path FB.
 3 Add a motion and Motion FB to design the motion along the path for the Motion-Point.

Motion Properties of Point along a Path

 A. The shape is given by the shape of the sketch.
 B. The magnitude of the motion is the given by the Motion and the shape of the sketch.

The motion in the X–axis and Y–axis directions are a combination of the shape and motion.

You can measure the Magnitude, X–axis and Y–axis motions with a Point-Data FB.

## Use the Blend-Curve and the Motion-Path FB

 •
 • Motion-Path FB - Basic
 • Blend-Curve and Motion-Path FB - Basic
 • Comparison of XY Piggyback Sliders and Blend-Curve

Tutorial and Reference Help Files for MechDesigner and MotionDesigner 13.2 + © Machine, Mechanism, Motion and Cam Design Software by PSMotion Ltd