Modelling Balancer in V-Rep

[antoronson]

Hello All
I am interested in modelling a balancer unit of an Industrial Robot in V-Rep. This balancer unit is a spring mechanism. When the body is moved away from home by motor, this spring expands, inducing more torque on motor. When it returns, the motor effect is almost nil as it returns with the effect of spring. I am interested to model it using V-Rep using the reciprocating joint for Spring and rotating for motor. Reciprocating joint has spring constant and force. If this reciprocating joint is somehow converted to a spring in V-Rep, the motor need to apply enough force to expand spring and return, the motor can apply zero force to return.
Can this be done in V-Rep.

[antoronson]

Hello All
i have a small update
Using the reciprocating joint, I am able to bring in the spring. I was also able to note down the force acting on the spring. My spring has an initial force, so that the expansion adds up to the initial force. I need to set up a spring with initial force and the given spring constant. So whenever the rotating joint rotates, it needs to give additional force for the spring also, since it is attached to the body2. Further when it retracts, automatically the body should be brought back by the release of accumulated tension in spring. Have anyone modelled such criteria, who can help me.

[coppelia]

Hello,

can you please clarify following:

• you have two bodies linked via a spring. Is body 1 static? Or are both bodies dynamic? In that case, are we in a situation of zero gravity, or on a frictionless surface?
• The motor on body 2 can only have an effect if it is attached to another body (e.g. a simple mass). Where is that mass?

Are you basically trying to control body 2's movement by having the spring effect and motor/inertia effect?

Cheers

[antoronson]

Hello
Thank you fro your reply
I hope this picture explains better

Body 1 is rotated around z axis and body 2 linked to body 1 is rotated around the axis perpendicular to z-axis. Now when the body2 rotates clockwise, I need the spring to be expanded with stored energy, while return, i need the spring to pull back the body 2.

[coppelia]

Ok, I see you have a loop there. So you should set-up your scene hierarchy like:

Code: Select all

body1 --> revJoint --> body2 --> dummy1
      --> sphericalJoint --> smallMass --> prismaticJoint(i.e. spring) --> smallMass --> sphericalJoint --> dummy2

Then you need to link dummy1 with dummy2 via a dynamic overlap constraint. Make sure the two dummies are in the correct position and overlap at simulation start

Cheers