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constraint create joint rackpin
A rack-and-pinion joint is a five-degree-of-freedom joint that constrains the rotational and translational displacement of the I marker as it rolls along the z-axis of the J marker.
Format:
Example:
constraint create joint rackpin
joint_name = a new joint adams_id = integer comments = string
i_part_name = an existing body j_part_name = an existing body
location = location orientation = location along_axis_orientation = location in_plane_orientation = location
relative_to = an existing model, part or marker i_marker_name = an existing marker
j_marker_name = an existing marker diameter_of_pitch = real number
constraint create joint rackpin &
joint_name = JOINT__1 &
adams_id = 2 &
comments = "comment string" &
i_part_name = part_1 &
j_part_name = part_2 &
location = 10 , 10 , 5 &
orientation = 1 , 2 , 1 &
relative_to = ground &
i_marker_name = marker_1 &
j_marker_name = marker_2 &
diameter_of_pitch = 0.2
Description:
Parameter Value Type Description
joint_name A New Joint Specifies the name of the new joint. You may use this name later to refer to this joint. Adams/View will not allow you to have two joints with the same full name, so you must provide a unique name.
adams_id Adams_id Specifies an integer used to identify this element in the Adams data file.
comments String Specifies comments for the object being created or modified.
i_part_name An Existing Body Specifies the part that is the first of two parts connected by this joint. Adams/View connects one part at the I marker to the other at the J marker. These markers are automatically generated using this method of joint creation.
j_part_name An Existing Body Specifies the part that is the second of two parts connected by this joint. Adams/View connects one part at the J marker to the other at the I marker. These markers are automatically generated using this method of joint creation.
location Location Specifies the locations to be used to define the position of a constraint during its creation. The I and J markers will be automatically created at this location on the I_PART_NAME and J_PART_NAME respectively.
orientation Orientation Specifies the orientation of the J marker for the constraint being created using three rotation angles.
The I marker is oriented based on the J marker orientation and the requirements of the particular constraint being created. These markers are created automatically.
along_axis_orientation Location Specifies the orientation of a coordinate system (e.g.
marker or part) by directing one of the axes.
Adams/View will assign an arbitrary rotation about the axis.
in_plane_orientation Location Specifies the orientation of a coordinate system (e.g.
marker or part) by directing one of the axes and locating one of the coordinate planes.
relative_to An Existing Model, Part Or Marker
Specifies the coordinate system that location coordinates and orientation angles are with respect to.
Adams/View Commands constraint create joint rackpin 58
Extended Definition:
1. For a rack-and-pinion joint, the x-axis of the pinion must be parallel to and pointed in the same direction as the z (translational) axis of the rack. The separation between the two axes should be one-half the pitch diameter of the pinion. The rack-and-pinion joint itself does not enforce the position and orientation it requires, but the chain of both parts and joints that connects markers I and J should enforce the position and orientation. A common approach for enforcing the position and the orientation is to support the rack with a translational joint and to support the pinion with a revolute joint.
2. Normally, entity names like the joint name are composed of alphabetic, numeric, or '_'
(underscore) characters, and start with an alphabetic or '_' character. They may be any length. By enclosing the name in double quotes, you may use other printable characters, or start the name with a numeral. If a name contains characters, or starts with a numeral, you must always quote the name when entering it. Note that you can specify the parentage of an entity (e.g. what part "owns"
a marker or a geometry element) when you CREATE it by changing the name. If you enter just the entity name, then the default parent will be assigned by Adams/View. If you type in the full name, then you may over ride the default parent. In most cases, when creating an entity, Adams/View will provide a default name. The default name that Adams/View provides will specify the parentage that it has assumed. You may, or course, delete this name and use your own.
The form of a full name is:
"...._NAME.GRAND_PARENT_NAME.PARENT_NAME.ENTITY_NAME"
The number of levels used varies from case to case and the parentage must exist before an entity can be assigned to it.
3. When you use the FILE ADAMS_DATA_SET WRITE command, Adams/View writes an Adams data file for your model. Adams requires that each modeling element be identified by a unique integer identifier. If you use this parameter to specify a non-zero identifier, Adams/View will use it in the corresponding statement in the Adams data file. You may also enter zero as an identifier, either explicitly or by default. The next time you write an Adams file, Adams/View will replace the zero with a unique, internally-generated identifier. Adams/View will permanently store this identifier with the element just as if you had entered it yourself. Normally, you would let all identifiers default to zero, and Adams/View would generate the identifiers for you. You are never required to enter a non-zero identifier. You only need to specify it if, for some reason, you wish to control the Adams file output.
i_marker_name An Existing Marker Specifies a marker on the first of two parts connected by this joint. Adams/View connects one part at the I marker to the other at the J marker.
j_marker_name An Existing Marker Specifies a marker on the second of two parts connected by this joint. Adams/View connects one part at the I marker to the other at the J marker.
diameter_of_pitch Length Specifies the pitch diameter of the pinion gear of a rack-andpinion joint.
Parameter Value Type Description
4. When an Adams/Solver data file (.adm) is read into Adams/View, all comments associated with a statement (from the end of the previous statement through the end of the current statement) are stored with the object. Comments in the data file can be associated with model. These comments must follow the title statement and be followed by the comment 'END OF MODEL
COMMENTS'. This string must be uppercase. When an Adams/Solver data file is written, the comments for an object are written before the statement corresponding to the object.
5. Adams/View will orient the coordinate system by starting from the initial coordinate system and applying three successive rotations. Depending on the convention you have selected, the rotations may occur about space-fixed or bodyfixed axes in any meaningful combination of the x, y, and z axes.
By default, you supply Euler (body313, or body-fixed z, x, z) angles. You may change this convention with the 'DEFAULTS UNITS ORIENTATION_TYPE=' command. For example, selecting SPACE123 means you will subsequently be supplying space-fixed x, y, and z angles.
Adams/View applies your orientation angles starting from the coordinate system you identify with the RELATIVE_TO parameter. The default for the RELATIVE_TO parameter is the default coordinate system.
6. For the along_axis_orientation parameter you may enter either one or two locations to direct the axis. If you enter one location, the axis will point toward the location. If you specify two locations, the axis will be parallel to, and pointing the same way as, the vector from the first location to the second. Note that this does not completely dictate the orientation of the coordinate system.
Adams/View will osition the coordinate system with an arbitrary rotation about the axis. If you must completely control the coordinate system orientation, use ORIENTATION or
IN_PLANE_ORIENTATION. By default, you direct the Z axis of the coordinate system.
You may change this convention with the 'DEFAULTS ORIENT_AXIS_AND_PLANE AXIS_AND_PLANE_SETTING=' command. For example, selecting either
X_AXIS_XY_PLANE or X_AXIS_XZ_PLANE means you will subsequently be directing the X axis. The plane-convention setting does not affect this parameter. Adams/View applies your location coordinates in the coordinate system you identify with the RELATIVE_TO parameter.
The default for the RELATIVE_TO parameter is the default coordinate system.
7. For the in_plane_orientation parameter you may enter either two or three locations. If you enter two locations, the axis will point toward the first location and the plane will fall on the second. If you specify three locations, the axis will be parallel to, and pointing the same way as, the vector from the first location to the second and the plane will be parallel to the plane defined by the three locations. By default, you direct the Z axis of the coordinate system and locate the ZX plane. You may use the 'DEFAULTS ORIENT_AXIS_AND_PLANE AXIS_AND_PLANE_SETTING=' command to change this convention. For example, selecting X_AXIS_XY_PLANE means you will subsequently be directing the X axis and locating the XY plane. Adams/View applies your location coordinates in the coordinate system you identify with the RELATIVE_TO parameter.
The default for the RELATIVE_TO parameter is the default coordinate system.
8. If the relative_to parameter is not specified, the default coordinate system is used. The default coordinate system is initially your model, i.e. the global coordinate system. You may change the default coordinate system using the 'defaults coordinate_system' command.
Adams/View Commands constraint create joint rackpin 60
9. The pitch diameter relates the rotational motion of the pinion to the translational motion of the rack. When the pinion turns in the positive direction around the z-axis of the I marker, a positive pitch diameter moves the rack in the positive direction along the z-axis of the J marker and a negative pitch diameter moves the rack in the negative direction along the z-axis of the J marker.
Tip: The I marker is at the center of the pinion, and the J marker is in the rack.