Honeywell’s New Sensors Self-Diagnose Internal Failures

August 21, 2017

William Kucinski

Honeywell claims its IHM sensor technology, which can be configured with an optional health monitoring output to a host system, is an improvement on traditional ECKO topology—the previous standard in aerospace applications. (Source: Honeywell)

In August, Honeywell announced a new series of self-diagnosing sensors designed to improve the performance of aircraft systems and reduce maintenance costs associated with false readings. The Integral Health Monitoring (IHM) series of aerospace proximity sensors can detect when a sensor has been damaged or impacted. The new sensor technology utilizes a unique circuit where, once an impact occurs and a metallic object is detected in front of the sensing face, a signal is passed through the conditioning circuitry to give an output configured according to the sensor application. In doing so, the sensor can detect any internal failures and display a fault output instead of a false positive or false negative.

"Aircraft operators who receive a sensor reading often cannot be sure if they have a system issue that needs to be addressed or if the sensor itself is malfunctioning," said Graham Robinson, President of Honeywell's Sensing and Internet of Things business. "Our circuit can detect whether a sensor reading is correct or the result of damage or some other problem with the sensor itself."

For instance, proximity sensors in aircraft landing gear systems provide a pilot with a fault alert on landing approach to warn if the landing gear is not completely deployed. However, the new health-monitoring sensors can indicate if the error message was caused by the sensor itself rather than an issue with the landing gear.

"Our proximity sensors can notify engineers or operators of potential issues with a system before or after the component fails," said Robinson. "The sensor fault-detection provides mechanics on the ground with the information they need to perform inspections and repairs without a long and costly troubleshooting process."

The IHM sensors are configurable, noncontact, hermetically sealed devices designed to sense the presence or absence of a target in harsh-duty aircraft applications (e.g., when a thrust reverser is not fully closed). The design eliminates mechanical failure mechanisms, reduces wear, minimizes downtime, and increasing reliability.

As Honeywell and other OEMs and suppliers design for the demand of next-gen aircraft and integrated vehicle health monitoring (IVHM), operators will be able to move away from scheduled maintenance cycle and concentrate on maximizing day-to-day operations, budget, and profit margins.

Honeywell claims that the IHM sensor technology, which can be configured with an optional health monitoring output to a host system, is an improvement on traditional ECKO (eddy current killed oscillator)—the previous standard in aerospace applications.

The sensors can be designed into a range of aircraft systems such as thrust reverser actuation systems, flight controls, aircraft doors, cargo loading systems, evacuation slide locks, and landing gears systems.

In addition to the IHM sensors, Honeywell also recently introduced LVDTs (linear variable differential transformers) for use in engine mechanisms, pilot controls, and nose-wheel steering applications. The LVTDs are designed to provide next-generation aircraft with continuous position monitoring and have also been developed for use in harsh environments. The LVDT sensors are already being incorporated into Honeywell-manufactured aircraft systems and can support other component and system manufacturers.