MRI robot/JHU 2007 07 10 Meeting

From CISSTwiki

Contents 1 Participants 2 Overview 3 Software design 4 Other

Participants

• Greg Fischer, JHU
• Csaba Csoma, JHU

Overview

Navigation Software ⇔ OpenTracker ⇔ Network ⇔ OpenTracker (BRPtprReceiver) ⇔ Named Pipe ⇔ Robot Controller (BRPtprControl)

Software design

• C++
• 2 threads in each process, one for each direction
• blocking read/write with named pipe

Other

• Watchdog for the network communication
  • Navigation Software sends a "ping" message every second
  • Robot controller goes into the "fault" state if there's no message for 5 sec

if (ThereIsMessage) {
 counter = 500;
 ProcessMessage(x);
} else {
 counter--;
 if (counter<=0) {
   NetworkFailure();
 }
}

• Command priority: what happens if there's 30 "GetPosition" in the queue, and "Emergency Stop" arrives?
  • Controller side: command priority
  • Controller side/Navigation Software side: group "GetPosition" messages into a single one