Error in simuscape model

Hello there.

I am new to simulink and simscape and I am trying to model a planar 2 DoF robot arm in simulink.

I have a picture of a simple shape and turned them into waypoints and these waypoints are used to produce polynomical trajectory.

I then turn these coodinates of trajectory into joint angles of the robot arm using inverse kinematics and use inverse dynamics from robortics toolbox to calculate torque.

But when I apply these torque into my simscape model, I am getting a error saying there might a singurality. How do I fix this error?

I have attached my simulink file with relevant script.

Answer 1

[Gowtham]

Hello Weilin,

I understand you are facing an issue while simulating a robot arm, related to the derivative of a state in the model.

I tried to reproduce the issue at my end with the given files and it ran smoothly without encountering any errors.

To address the error you are experiencing, I suggest following the steps outlined below:

1. In the model configuration parameters, navigate to Solver and adjust the type of solver to ‘Variable-step’ and set the Solver to “ode15s” (stiff/NDF).
2. If the issue still persists, proceed to the configuration parameters, and under Diagnostics > Data Validity > Signals, set the ‘Inf or NaN block output’ to ‘error’ and then rerun the model. This action will prompt an error message, which reads as follows:

• 
• To address this issue, ensure that you eliminate the ‘divide by zero’ error in ‘simulink_test1/Torque prediction/MATLAB Function1’, which generates an ‘Inf’, leading to the error.

Kindly refer to the following MATLAB Documentation for further information on ‘ode15s’ solver and ‘NaN’

• https://www.mathworks.com/help/simulink/gui/solver.html
• https://www.mathworks.com/help/matlab/matlab_prog/infinity-and-nan.html

Hope this helps.

Best Regards,

Gowtham