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Working with Higher-Pair Constraints

ADAMS/View provides you with two types of higher-pair constraints: point curve and 2D curve-curve. See table 2.6.

Table1 2.6 Higher-Pair Constraints in ADAMS/View

 Icon Higher-Pair Constraints An example Constrains the following pin-in-slot The point-curve constraint restricts a fixed point defined on one part to lie on a curve defined on a second part. The first part is free to roll and slide on the curve that is fixed to a second part. The curve on the second part can be planar or spatial, or open or closed. A point-curve constraint removes two translational DOF from your model. Point-Follower 2D curve-curve A 2D curve-curve constraint restricts a curve defined on the first part to remain in contact with a second curve defined on a second part. The curve-curve constraint is useful for modeling cams where the point of contact between two parts changes during the motion of the mechanism. The curve-curve constraint removes three DOF from your model.

To create a point-curve constraint:

1) From the Jointpalette, select the Point-Curve Constrainttool .

2) In the settings container, set whether or not you will be selecting an edge or curve:

Ÿ Curves- Splines, chains, and data-element curves are all considered curves.

Ÿ Edge- An edge is one of the wireframe outlines drawn on a solid.

3) Select a point on a part that will travel along a curve.

4) Select the curve or edge along which the point will travel. The curve can be closed or open. Note that when you select a closed curve, the Dynamic Model Navigator highlights only a portion of the curve. ADAMS/View will use the entire curve.

To create a 2D Curve-Curve constraint:

1) From the Jointpalette, select the 2D Curve-Curve Constrainttool .

2) In the settings container, for each part, set whether or not you will be selecting an edge or curve:

Ÿ Curves- Splines, chains, and data-element curves are all considered curves.

Ÿ Edge- An edge is one of the wireframe outlines drawn on a solid.

3) For a curve-on-curve cam, select a curve or edge that will travel along a second curve.

4) Select the curve along which the first curve will travel. The curve can be closed or open. Note that when you select a closed curve, the Dynamic Model Navigator highlights only a portion of the curve. ADAMS/View will use the entire curve.

Date: 2015-12-18; view: 633

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