applying external force and torque on a specified point

I have a 2 link mechanism (a robotic arm) and i wanted to apply external force on arm 2. I wanted to computer torque by applying force on different locations of arm 2. as torque is F*d so by changing d i wanted to know how much torque is needed by my joint to move from 90degree to 45 degree. I have added extrnal force block from simscape multibody and it is applying force only on axis. It will be highly appericiated if you can please slve this problem.

Viswal 2 is the block where i wanted to apply force. and wanted to compute the torque at joint.

I am also attaching 4 file so anyone how is replying can understant my query better.

Thanks in advance

[jari jafri]

Answer 1

[Raj]

Hi Jari,

I went through your query and as per my understanding, you wish to apply external force on different points along the length of the rod.

I also had a similar issue and managed to find a workaround. You can add frames in your solid to achieve this. Frames can be created at specific locations on the geometry, based on its features such as surfaces, curves, and points.

Given the solid geometry, this essentially means that the possibilities for frame creation are limited to the cross-sectional areas, at either end or at the midpoint. If the provided geometry-based frame options in that cross-section are not sufficient, you can use a 'Rigid Transform' block to offset the frame location in that cross-section.

For adding Frames you can go to 'Frames' under the Properties section in the 'Solid object' box and select the appropriate frame position.

For better understanding on the same, you can refer to the following documentation links-

• 'Brick Solid' block- https://www.mathworks.com/help/sm/ref/bricksolid.html
• 'Rigid Transform' block- https://www.mathworks.com/help/sm/ref/rigidtransform.html

I hope this explanation helps you proceed ahead with your project!

[mohammad tajdani]

Hi Raj, would you please send an example for this situation?