How to change the direction of rotation of gears in revolute joint block by giving torque inputs?

I have been woking on a 6DOF manipulator. So, I have calculated torques using lagrange's equation of motion for each joint. So, when I use these values as input for which I am expecting motion of a particular joint to be in anti-clockwise motion, but it turned out to be clockwise. I tried by changing the sign of input, but that did not change the any effect. So, can anyone please tell me where I am doing wrong?

And for my robot, there is some configuration for which at that particular joint in static conditions that is at time = 0; there must be some value of torque for which the robot can be in that configuration with falling due to gravity. So, why the measured values from the joint values using total torque is actually zero instead of some torque value?

Answer 1

[Steve Miller]

Hi Shravista,

If you change the sign of the torque that actuates a joint, it will actuate the joint in the opposite direction. If you're not seeing that effect, then perhaps your model isn't constrained properly or perhaps there is another effect in your model that is masking the effect of the sign change.

As far as Total Torque is concerned, if (for example) you have an inverted pendulum that is pointing directly up, no torque is required to hold it there. That would be one example of a configuration that would match your observation.

If you share the model, perhaps we can help further.

--Steve

[Shravista Kashyap]

Thanks for your reply, I will share it in this post here.