about difference control rule

Hi, friends:
I am doing a research in a discrete time system with time delay. This system is implied in networked haptic display. this system has two haptic
displays in the remote situation.
I use position control rule, position: Y1=x1-(1/z)x2 and position: Y2=x2-(1/z)x1 as input to virtual environment, where x1 and x2 are represent position of two haptic system seperatedly, force of operators is input, (1/z) is time delay, when it touch the virtul environment,I hope to generate the virtual feedback force. Now, I only think about the simpliest virtual envirnoment, thus, I use virtual spring with paramater k to represent virtual environment. I use Y1-Y2=(1+(1/z))(x1-x2) and Y2-Y1=(1+1/z)(x2-x1) as virtual feedback force, but it does't work well, anybody can give me some hint, normally, when we use difference position control rules, how to get the force feedback! Thank you very much!
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
Add image file

Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here. All logos and trade names are the property of their respective owners.