2.3.3.3 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 Joint palette, select the Point-Curve Constraint tool .

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

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

• 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 Joint palette, select the 2D Curve-Curve Constraint tool .

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

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

• 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.

2.3.3.4 Working with Motions generators

A motion generator dictates the movement of a part as a function of time. It supplies whatever force is required to make the part satisfy the motion.

ADAMS/View provides you with the following types of motion:

• Joint Motion - Prescribes translational or rotational motion on a translational, revolute, or cylindrical joint. Each joint motion removes one DOF from your model. Joint motions are very easy to create, but they limit you to motions that are applied to the above listed joints and movements in only one direction or rotation.

• Point Motion - Prescribes the movement between two parts. When you create a point motion, you specify the direction along which the motion occurs. You can impose a point motion on any type of idealized joint, such as a spherical or cylindrical. Point motions enable you to build complex movements into your model without having to add joints or invisible parts.