Combatant Watercraft Performance and Maneuvering Telemetry Analysis with NI LabVIEW

Author(s):
Richard M. Brueggman - Data Science Automation Inc.
Benjamin A. Rayner Jr. - Data Science Automation Inc.
Gregory C. Cala - Data Science Automation Inc.

Industry:
Water/Wastewater, Government/Defense

Products:
LabVIEW

The Challenge:
Developing a versatile, laptop-based application to automate the acquisition and analysis of data to evaluate and characterize combatant watercraft used by the various branches of the U.S. military.

The Solution:
Using National Instruments LabVIEW, LabVIEW State Diagram Toolkit, and USB-232 to create the application.

Watercraft Test Requirements

We were selected to improve test capabilities through automation to quantify performance characteristics of hull, electrical, mechanical, and propulsion systems. The versatile system needed to address the diverse range of watercraft from 14ft rubber inflatable rafts to 250 ton surface effect ships and from 170ft coastal patrol ships to hydrofoil troop transports.

Some of the specific measurements included craft weighing, propulsion system performance, dynamic trim, fuel consumption, and craft speed, control and maneuverability. This application is for the last of these measurements – craft speed, control, and maneuverability. Originally, we measured these physical characteristics during live on-water trials using manual testing and analysis procedures. The demands of testing a vessel in potentially rough waters, the expense of repeating performance trials, and the intense labor and time involved in the manual data collection and postprocessing forced the following automated system requirements. We needed a portable, self-contained, fault-tolerant solution that required minimal user interaction. It had to share GPS readings with commercial navigation software and perform integrated postprocessing of the data, including the adaptation of shore-based GPS analysis procedures.

A Fault-Tolerant System

We developed a new, turnkey solution to automate the process using NI LabVIEW 7.1, the NI LabVIEW State Diagram Toolkit, and the NI USB-232 adapter installed on a laptop and interfaced with a set of battery powered data acquisition devices. We selected the USB-232, a critical component of the application, because it did not require an external AC adapter. We used NI-VISA to control and monitor the serial port during the tests.

At design time, we addressed the complexities associated with developing a fault tolerant application. We implemented the application’s fault tolerance at multiple levels to address a wide range of failure scenarios, including loss of electrical power, and safety hazards. Using the LabVIEW State Diagram Toolkit, we considered and accounted or failures ranging from defective sensors and loss of satellite feeds to complete subsystem failures. A secondary benefit of using the LabVIEW State Diagram Toolkit was that we could quickly and easily integrate fault scenarios that we did not anticipate at design time during development. We implemented the resulting client-server architecture as an event structure to support the user interface and to maintain state and status of each subsystem.

GPS Feed Challenges

Because we did not want a separate GPS antenna for each system, the GPS feed for tracking craft location had to be accessible from a standard laptop-based navigation package that concurrently ran on a separate PC from the LabVIEW application. Any problem that affected the serial port’s ability to concurrently support two distinct tasks would render the system useless.

We accomplished supplying the GPS feed to the commercial navigation software while monitoring and logging the updates with LabVIEW using a creative hardware and software solution. The hardware involved building a custom serial cable that helped the serial port’s read line to monitor the instrumentation feed while the transmit line was available to drive one of the laptop’s serial ports. The GPS software component feed-sharing duplicated the valid receive packets and retransmitted them using the serial port’s transmit line. Using this combined hardware and software approach, we developed and tested the LabVIEW application using computers that did not have the navigation software installed and did not require any modification.

Minimal User Interaction

Based on the challenging test conditions encountered, minimal user activity was critical. We could not rely on the user to interact with the application when safety concerns demand their attention or action. We addressed the minimization of user interaction with the application in each of the three phases (setup, collection, and analysis) of a typical test run.

We logged a large number of test condition parameters with the data acquired during each trial. Most of this information is known by the user prior to the date of the test. Therefore, all configuration information could be selected and entered during setup, in advance of system deployment to the vessel under test. Then, at the time of the test, the user needs only to load the appropriate header file.

User interaction during the collection phase of the maneuvering tests was a considerable concern. During maneuvering trials, we needed to note the vessel position each time the craft’s heading had rotated a multiple of 90 degrees from the approach heading, a process called marking. We implemented an automatic marking algorithm that required the user to mark only the beginning of the turn. Using the automatic marking, the user concentrated on surviving what could be a 17s, 540 degree turn in rough waters.

Immediately after the trial was completed, the user reviewed the results via integrated postprocessing. During the trial run analysis phase, we implemented the automatic marking algorithm and corrected the recorded vessel’s track before making the required measurements.

NI Products Increase Productivity

The DSA engineers’ creativity and the versatility of the NI products we used made this project a unique success. During each test, we save considerable time and money. In addition, we improved safety and produced more accurate combatant watercraft maneuverability results. The manual postprocessing method required days to evaluate, and even longer to reschedule the necessary resources if retesting proved necessary. With the new automated analyses, the user can immediately determine if retesting is necessary for a significant improvement in productivity.

For more information, contact:

Richard M. Brueggman

Founder, President, and CEO

Data Science Automation

400 Southpointe Boulevard, Suite 210

Canonsurg, PA 15317

Tel: (724) 745-8400

Fax: (727) 745-8461

E-mail: rmb@DSAutomation.com

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