Incorrect torque measurement in revolute joint

These past few days I've been working on simulating walking using a structure created in Simulink. To do this, I've designed a leg with three joints: ankle, knee, and hip. This leg is anchored to an horizontal bar which is connected via two prismatic joints to two vertical bars, one on each side of the horizontal bar, as shown in the attached image. To simulate the walking pattern, I've inserted the angles corresponding to the walking patterns. The kinematics seem to work perfectly with the movements I desire, but the issue arises when measuring the torque of any of the joints using the torque sensing option of the revolute joints. Excessively high torque values are measured, so I'm reaching out to you for help in identifying what needs to be changed to correct the measurement error.

Answer 1

[Divyanshu]

Hi Enrique,

Please go through the following pointers:

• If you are using 'Simulink-PS Converter' block for specifying values of External Force & Torque, then make sure to specify appropriate Value for 'Input Signal Unit' options in Block Parameters for 'Simulink-PS Converter'.
• Also refer the following documentation which talks about different parameters of Revolute Joint and what is the purpose of different sensing options, specifically 'Internal Mechanics', as they affect the torque acting on joint.
• https://www.mathworks.com/help/sm/ref/revolutejoint.html

I tried to simulate a Model with Simpler Kinematics but could not reproduce any such high unexpected torque values.