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The Human Touch with iRemote

Maintained by: Paul Newman Get PDF

1  Overview
2  Summary of Functionality
3  Informing the Pilot

1 Overview

This section will give you a description of how to use and configure iRemote to inject commands into a community and also to query the status of certain commonly used variables from a terminal. iRemote was designed to be a control terminal for a deployed vehicle. It is really nothing more than a long switch statement based on characters input from the keyboard. One of its many functions is to allow remote control of the actuators of the vehicle. This is an invaluable asset for land and sub-sea vehicles alike.

The application is multithreaded. The primary thread blocks on a read of keyboard input. When a character is pressed some action is taken - for example publishing a new value for DESIRED_THRUST. The fact that iRemote can take control of a real vehicle presents a safety problem. What if the human controller walks away or even worse the vehicle moves out of communication range (eg a submarine dives) and the console is not available? To prevent the last issued actuator command being carried out ad-infinitum a secondary in thread iRemote prompts the user to hit an acknowledge key (') at least every 15 seconds. If the human driver does not respond then all actuators are set to the zero position.

2 Summary of Functionality

The following (not exhaustive) list describes some of the online functionality that iRemote provides:

Function	Key	Comment
Restart Logger	G	Tells pLogger to begin recording to a new set of log files
Begin Mission	O	Instructs the helm to go online
Halt Mission	spacebar	The helm goes offline and iRemote takes control immediately.
Navigation Summary	*	Prints a summary of salient navigation information
Rudder Left/Right	n,m	Steer control
Elevator Up/Down	p,l	Pitch control
Thrust Up/Down	a,z	Throttle control (+ shift gives 100 percent)
Stop	spacebar	Immediate zero of all degrees of freedom
Fetch DB	F	Prints a summary of the contents of the entire MOOSDB
CustomKey	[0,...,9]	The numeric keys can be made (via iRemote configuration block) to publish any named variable with a specified value. In the example configuration block below (Listing 2.1), pressing key "2" will cause iRemote to write the variable JANITOR_SWITCH with the string value "ACTUATION::OFF"
CustomSummary	+	The configuration block allows a custom summary to be built consisting of any variable names used within the system. iRemote subscribes to this data and prints its current value when requested.
CustomJournal	[0,...,9]	Similar to CustomSummary but instead of keeping the most recently published variable it keeps a history of values. Each Journal can be bound to a numeric key. In the example below pressing key "6" will show the past 10 values of DESIRED_RUDDER with every delta captured as the capture time is 0.

Table 2.1: iRemote keyboard mappings.

Listing 2.1 - An example onfiguration block for iRemote showing typical usage of the CustomX commands.

  1  //-----------------------------------------------------------------
  2  // iRemote config block
  3   
  4  ProcessConfig = iRemote
  5  {
  6    CustomJournal = Name = DESIRED_RUDDER,Key =6, History = 10,Period = 0
  7    CustomSummary = DESIRED_THRUST
  8    CustomKey = 2 : JANITOR_SWITCH @ "ACTUATION:OFF"
  9  }

3 Informing the Pilot

In most missions iRemote is the only interface the vehicle pilot has with the vehicle. Clearly then a method is needed by which important information can be sent to the iRemote console from any process. The CMOOSApp member function MOOSDebugWrite achieves this by issuing a notification on a variable watched by iRemote. Such messages are displayed on the iRemote console at run time along with the process making the announcement. Note that this name is somewhat unfortunate as this function should not be used for debugging - it is a run-time thing. It is frustrating to have a cornucopia of messages flashing on the screen during a mission the content of which is meaningless to the pilot. Typical uses of this functionality would be a very occasional summary of navigation status and system level warning messages - for example notification of unexpected mission task termination.

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