executive_control set kinematics_parameters
KINEMATICS_PARAMETERS allow control over the kinematic simulation in Adams. Kinematics parameters include error tolerances and other parameters for kinematic analyses. You would set these parameters only when you are requesting a kinematic analysis and you want to change one or more of the tolerances and parameters from the default values.
Format:
executive_control set kinematics_parameters |
|---|
model_name = | model_name |
alimit = | real_number |
error = | real_number |
maxit = | integer_number |
aerror = | real_number |
amaxit = | integer_number |
tlimit = | real_number |
hmax = | real_number |
pattern_for_jacobian = | yes/no |
apattern_for_jacobian = | yes/no |
Example:
executive_control set kinematics_parameters & |
|---|
model_name= | model_1 & |
pattern_for_jacobian = | yes & |
apattern_for_jacobian = | yes |
Description:
Parameter | Value Type | Description |
|---|
model_name | String | Specifies the model to be modified. You use this parameter to identify the existing model to be affected with this command. |
alimit | Real number | Specifies the maximum angular increment Adams is to allow per iteration. Can take a real value greater than zero. |
error | Real number | Specifies the maximum relative displacement error Adams is to allow. Can take a real value greater than zero. |
maxit | Integer number | Specifies the maximum number of iterations Adams is to allow for finding static equilibrium in a static equilibrium analysis. Can take an integer value greater than zero. |
aerror | Real number | Specifies the maximum acceleration error Adams is to allow for each time step during a kinematic solution. |
amaxit | Integer number | Specifies the maximum number of iterations Adams is to allow for finding accelerations at a point in time during a kinematics solution. |
tlimit | Real number | Specifies the maximum translational increment Adams is to allow per iteration. |
hmax | Real number | |
pattern_for_jacobian | Yes/No | Specifies as many as ten character strings that together establish the pattern for evaluating the Jacobian matrix during Newton-Raphson iteration. |
apattern_for_jacobian | Yes/No | Specifies as many as ten character strings that together establish the pattern for Jacobian evaluations during acceleration solution. |
Extended Definition:
1. Kinematics parameters include error tolerances and other parameters for kinematic analyses. You would set these parameters only when you are requesting a kinematic analysis and you want to change one or more of the tolerances andparameters from the default values.
2. A kinematic analysis is only appropriate when a system has zero degrees-of-freedom. A kinematic analysis solves for the displacements, velocities, accelerations, and forces (if any) at a series of points in time. To find the displacements, Adams uses Newton-Raphson iteration to solve a nonlinear set of algebraic equations. After finding the displacements, Adams solves linear equations without iteration to find the velocities, accelerations, and forces. Adams repeats this procedure at successively later times until it obtains results over the period of time specified in the Adams SIMULATE command.
3. You may identify a model by typing its name or by picking it from the screen. If the model is not visible on the screen, you must type the name. You may also find it convenient to type the name even if the model is displayed. You must separate multiple model names by commas. If the model is visible in one of your views, you may identify it by picking on any of the graphics associated with it.
4. The parameter PATTERN_FOR_JACOBIAN specifies as many as ten character strings that together establish the pattern for evaluating the Jacobian matrix during Newton-Raphson iteration. For each iteration, T or TRUE indicates that Adams is to evaluate the Jacobian, or F or FALSE indicates that Adams is not to evaluate the Jacobian. Thus cj determines whether or not Adams is to evaluate the Jacobian at the jth iteration. If necessary, Adams repeats the pattern of evaluation until it reaches the maximum number of iterations (MAXIT). The number of Y's or Yes’s and N's or No's, together, must be at least one and no more than ten. PATTERN defaults to Y:Y:Y:Y:Y:Y:Y:Y:Y:Y, i.e. to evaluating the Jacobian at every iteration.
5. The parameter APATTERN_FOR_JACOBIAN specifies as many as ten character strings that together establish the pattern for Jacobian evaluations during acceleration solution. For each iteration, T or TRUE indicates that Adams is to evaluate the Jacobian, or F or FALSE indicates that Adams is not to evaluate the Jacobian. Thus cj determines whether or not Adams is to evaluate the Jacobian at the jth iteration. If necessary, Adams repeats the pattern of evaluation until it reaches the maximum number of iterations (AMAXIT). The number of Y's or Yes’s and N's or No's, together, must be at least one and no more than ten. PATTERN defaults to Y:Y:Y:Y:Y:Y:Y:Y:Y:Y, i.e. to evaluating the Jacobian at every iteration.
Cautions:
1. AERROR must be greater than zero, and defaults to 1.0E-04.