NotImplementedError: No touch sensors for this robot!

@stepjam 
Hi, Stephen:

I meet the error using **ur5** as manipulator simulator to generate demos when to reproduce your paper. Would you mind sharing the details how to run this code in ur5 robot?
![image](https://user-images.githubusercontent.com/32757213/227500647-ce839423-01b1-4c2c-a8b9-40c86e52c51e.png)
