Function Expression for Force based on Joint Speed in Ansys Motion,

[B10838033]

I am using Ansys Workbench Motion and need to define a force that dynamically updates based on a joint's rotational speed during the solution (e.g., the force increases as the speed increases).

 

Could you please advise on:

 

What is the exact Function Expression syntax to extract a joint's rotational speed in a specific direction (e.g., Z-axis)?

 

How can I integrate this speed variable into a Force expression correctly?

 

Any simple syntax examples would be highly appreciated.

 

Best regards,

[dlooman]

Does the explanation below help?  

How do you specify a joint moment as a function of rotational velocity in the Motion product?

In Ansys Motion you can apply a joint moment via a function expression, and this function can use a measure (such as the joint’s rotational velocity) as its input; you define the velocity measure for the joint, then assign it as the input of a torque (moment) function so that the applied torque becomes a user-defined function of that velocity.

1. Applying a joint moment using a function expression

• You can create a Joint Moment load and set its Moment to Function Expression, then select a torque expression (for example based on STEP or other functions) as the definition of the joint moment. 
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• In the Details of “Joint Moment”, the torque can be defined directly as a function expression (e.g. a step torque using STEP(TIME,…)), and this mechanism is the same place where you would use a velocity-based expression once the velocity is available as an input measure. 
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2. Getting joint rotational velocity as an input measure (command-based)

• The developer API provides a way to obtain the joint velocity: a joint is first found using CS_Joint.Find(_jid), and then its velocity measure is obtained with joint.GetVelocity(). 
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• That velocity measure can then be assigned as the input measure of a load (actuator) using load.SetInputMeasure(vel); this is how you connect the joint’s rotational velocity to the function driving the torque.