CWAS Upgrade Project – Computer Based Simulation Software Test & Validation Report
- E. Runnerstrom, et. al
- MPR Document Number 0552-0004-407,
As the Navy builds ships with more complex, distributed systems, centralized control of distributed systems becomes a single point of failure. This is particularly important for recovering from damage, when the rapid execution of complex tasks often is necessary to effectively recover from damage. A control system that is vulnerable to damage when it is needed most, when recovering from damage, presents a significant survivability concern. The Navy Research Laboratory’s Damage Control Automation for Reduced Manning (DCARM) program demonstrated that automated “distributed control” results in more a survivable control system than the centralized control architecture typical aboard today’s Navy ships. The Chilled Water Automation System being installed aboard new construction DDG 51 Class destroyers is the first installation of the “distributed control” technology developed by the DC-ARM Program. Live fire weapon effects testing for the DD (X) program demonstrated the superior survivability of this “distributed control” technology for fluid systems. As used in this paper, “distributed control” is the distribution of control capabilities throughout a system as opposed to “central control” in which control functions for a system are performed by a central computer (or by redundant, yet still centralized control computers). A key feature of properly designed distributed control is that there is less dependence on long communication paths between sensors, the control processor, and the control actuators. This reduced dependence on vulnerable communications improves the survivability of the controls. In a properly designed distributed control system, the control decisions at each distributed component are likely to be simpler than a total system control logic in a centralized processor. The resulting simplicity makes the development and maintenance of a distributed system easier, and it typically leads to a more robust, more reliable system. To achieve the benefits of a distributed control system, it must be properly designed. This paper highlights a successful control system design approach, how that approach was applied in a complete prototype control system and how aspects of that control system were transitioned for shipboard application.