Mechanism Design and Mechanism Dynamics > Mechanism Dynamics > Other Measures > About Loadcell Reaction Measures
About Loadcell Reaction Measures
Use a loadcell reaction measure when you run a force balance analysis. You must create the loadcell lock on the Preferences tab of the force balance Analysis Definition dialog box, and run the analysis before you can get the value of the measure in the Measure Results dialog box.
You can think of a force balance analysis as an inverse static analysis. When a static analysis is run, the software searches for a configuration in which all the loads and forces in your mechanism are balanced. A force balance analysis is a way to obtain information on the loads needed to balance your mechanism before running a static analysis. The loadcell lock is a device to isolate a portion of your model and obtain a balancing load for it.
Your goal is to reach a state in which all loads and forces balance so that the mechanism cannot move. Before you run a force balance analysis, you must reduce your mechanism to zero degrees of freedom. You do this by locking bodies and connections or by creating a loadcell lock. Any servo motors, springs or dampers you have applied to a connection also reduces the connection's DOF. You then run the force balance analysis. If you have applied a loadcell lock, a message box opens with the magnitude of the force required to balance the mechanism at the specified point in the specified direction. You can also view this quantity by creating a loadcell reaction measure.
Keep the following in mind when defining a loadcell lock:
A loadcell lock requires that you specify a point or vertex, a body, and a force direction.
The balancing force is applied at the point or vertex you select. The point or vertex must be associated with a non-ground body.
The LCS of the selected body is used to reference the direction vector. This body, and the body associated with the point where the force is applied, can be different.
After you select the body for the LCS, you are prompted to enter the coordinates for the direction vector. A shaded, magenta arrow is displayed, indicating the direction of the force vector.
You can define several loadcell locks, but only one can be active during the force balance analysis.
Once you define the direction of the force vector, you cannot edit it. If you want to change the direction of the force, create another loadcell lock.