Aerospace and Electronic Systems - March 2019 - 12

The Adaptive Avionics Platform

Figure 6.
ACMS lab demonstrator.

distributes the C-APPs from its repository to the CPMs
and triggers the initialization phase of each C-APP.

COMMUNICATION ROUTING (STEP 4)
During initialization, all C-APPs and P-APPs publish and
subscribe all required topics. The CORG collects all topics
and calculates publisher-subscriber matches. Based on the
topology, routes for every topic are calculated as virtual
channels, i.e., the shortest path is determined through the
backbone topology. The determined routes are forwarded
to the in-router and out-router partitions. In addition, the
SWIs are configured to provide a static routing of topics
according to the virtual channels. Moreover, an alternative
route is determined and configured as a passive routing
table to the SWI. The alternative routing table is activated
if the shortest route becomes unavailable.

SELF-VERIFICATION (STEP 5)
The CORG runs a set of verification operations.
1) It checks that each module is alive and responsive.
2) It checks that each distributed application is initialized and does not report any error. 3) It checks that
each topic has at least one matching publisher-
subscriber pair. 4) The routing tables in all SWIs
are verified against the calculated routing in step 4.
5Optionally, a model of the expected topology is compared with the detected topology [31].

START OF THE STANDARD PHASE (STEP 6)
The CORG signals all P-APPs and C-APPs to enter the
standard phase. The scheduler on each module is started.
Afterward, the CORG can be disconnected. No further
self-configuration is possible.
12

FAULT-TOLERANCE MECHANISMS
The AAP provides two kinds of fault-tolerance. 1) CPMs
are grouped into redundancy groups. All CPMs of the
same group run the same applications, but only one is the
master. All other CPMs are slaves. The topic and routes
for all slaves are preconfigured, but passive during the
NOP. The CPMs of the group exchange status information
on their own quality-of-service (QoS). The QoS is calculated from the hardware status and the number of visible
peripherals of each CPM. If the QoS ranking between
CPMs changes over a confirmation time, the CPM with
the highest QoS becomes the new master. The silent topics
become active and the degraded CPM becomes silent.
2) If the PLAMA supervisor identifies a communication
problem, the master CPM reconfigures the SWIs with an
alternative route that isolates any faulty SWI or link. In
addition, IOMs that send corrupted messages over a short
confirmation time are isolated.

VERIFICATION AS AN ACMS
Based on the AAP concept and methods, an ACMS
demonstrator was developed, which is depicted in
Figure 6. The ACMS comprises a typical cabin electronics architecture, cabin applications, and peripherals.
The design goal is the verification of the AAP capabilities in real hardware.

HARDWARE AND SOFTWARE OF THE ACMS
DEMONSTRATOR
All modules are x86 small form-factor computers
equipped with UBUNTU 12.04.5 LTS. IOMs and SWIs

IEEE A&E SYSTEMS MAGAZINE

MARCH 2019

Aerospace and Electronic Systems - March 2019

Table of Contents for the Digital Edition of Aerospace and Electronic Systems - March 2019