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:

Ÿ 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.

Ÿ 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.

Joint Motion

You can create two types of joint motion.

Ÿ Translational- For a translational motion, ADAMS/View moves the first part that the joint connects along the z-axis of the second part.

Ÿ Rotational- For a rotational motion, ADAMS/View rotates the first part that the joint connects about the z-axis of a second part. The right-hand rule determines the sign of the motion. The z-axis of the first part must be aligned with the z-axis of the second part at all times. The angle is zero when the x-axis of the first part is also aligned with the x-axis of the second part.

To create a joint motion:

1) From the Motiontool stack or the Jointpalette, select the joint motion tool representing the motion that you want to create. Select either:

Ÿ to create a translational motion.

Ÿ to create a rotational motion.

2) In the settings container, specify the speed of the motion in displacement units per second. By default, ADAMS/View creates a rotational motion with a speed of 30 degrees per second and a translational motion with a speed of 10 millimeters per second.

To enter a function expression or user-written subroutine, right-click the Speedtext box, point to Parameterize, and then select Expression Builderto display the ADAMS/View Function Builder.

3) Use the left mouse button to select the joint on the screen to which the motion will be applied.

Modifying a Joint Motion:

You can change several properties about a joint motion after you create it. The properties include:

Ÿ Joint to which the motion is applied.

Ÿ Motion direction, either rotational or translational.

Ÿ Motion definition, including displacement, velocity, or acceleration.

Ÿ Initial conditions for displacement and velocity.

Point Motion

There are two types of point motion that you can create:

Ÿ Single point motion- Prescribes the motion of two parts along or around one axis.

Ÿ General point motion- Prescribes the motion of two parts along or around the three axes (six DOF).

To create a point motion:

1) From the Motiontool stack or the Jointpalette, select the tool representing the type of point motion that you want to create. Select either:

Ÿ to create a single point motion.

Ÿ to create a general point motion.

2) In the settings container, specify the these options.

3) If you selected to explicitly select the parts to which the motion is to be applied, select each part using the left mouse button.

4) Place the cursor where you want the motion to be located and click the left mouse button. If you selected to specify its location on each part, place the cursor on the second location, and click the left mouse button.

5) If you selected to orient the joint along a direction vector on a feature, move the cursor around in your model to display an arrow showing the direction you want the motion oriented. When the direction vector shows the correct orientation, click the left mouse button.

Date: 2015-12-18; view: 1331