Advanced Load Sensing technology for Aerospace Application

Project Information

TecALSens

Grant agreement ID: 821135

DOI

10.3030/821135

Project closed

EC signature date 18 October 2018

Start date 1 November 2018

End date 31 October 2021

Funded under

• SOCIETAL CHALLENGES - Smart, Green And Integrated Transport

Total cost

€ 865 157,50

EU contribution

€ 605 610,25

Coordinated by

TECSIS GMBH
Germany

Periodic Reporting for period 3 - TecALSens (Advanced Load Sensing technology for Aerospace Application)

Reporting period: 2021-02-01 to 2021-10-31

Summary of the context and overall objectives of the project

Future aircraft architectures like more and all-electric aircraft foresee a more extensive use of electrical actuators and higher level of load monitoring for primary and secondary flight control and landing gears.
Current load sensing solutions are mostly based on bonded strain gauge technology and on the insertion of LVDT (Linear Variable Differential Transformer) sensors. More innovative and “smart” components require more reliable and stable load sensors, which overcome the drawbacks of bonded strain gauge technology. New devices should enable a smooth integration with existing or innovative aircraft systems as well as with on-board electronics. The scope of the TecALSens project is to develop and deliver a load sensor able to enhance current load sensor technology and to provide the aeronautic industry a new class of products ready for validation at system and aircraft level. Air traffic contributes to overall well-being but also to the impact on air quality. Within the Systems ITD Platform new aircraft architecture are being analysed for accomplishing with the environmental objectives set by ACARE: Reduction of CO2 emissions by 50% per passenger and kilometre, reduction of NOx emissions by 80%; reduction of perceived noise by 50%.
The more- and all-electric aircraft configurations represent a new approach to overall aircraft architecture. Replacement of hydraulic and pneumatic systems by means of electrical systems like electro-mechanical actuators (EMA) contributes to more efficient fuel burning by reducing energy consumption of on-board systems and their weight, enabling an optimisation of energy management and reduction of pollutants’ emission.
Load measurement is crucial for many systems and supports future technology trends and the achievement of environmental objectives. The integration of Electro-Mechanical Actuators (EMA) requires the insertion of load sensors for monitoring and controlling actuator’s performance. Load monitoring delivers valuable data for health monitoring and durability prognostic. TecALSens addresses all these challenges and focuses on the development of a load sensor able to satisfy this request. Main objective of the TecALSens project is the development of a new load sensor based on thin-film technology. The new product offers new possibilities considering safety, integration, reliability and stability. The new load sensor must be able to fulfil the challenging requirements set for an aeronautic device for integration in primary and secondary flight control systems. At the end, the load sensor will be developed up to TRL 5.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

TecALSens represents an innovative project aiming at delivering a class of load sensors based the thin-film sensor technology. Primary and secondary flight control and landing gear have been considered for implementation of the load sensor. Each application has been thoroughly analysed considering feasibility, force measurement possibilities and integration issues.
The landing gear system has been selected as target application. For this, weight on wheel is the main objective of the load measurement, which has been extended to two perpendicular directions for accounting for landing as well as on-ground loads.
An analysis of currents state of the art of force sensor applications in aeronautics has been conducted. Resistive-effect-based load sensing (especially strain gauges and thin-film sensors) better fits to general project requirements considering force range, maturity level, applications and expected stability and accuracy. Thin-film-based load sensing elements have been selected as promising technology for the purposes of the project. During batch 1, the complete load sensor – electronic and mechanical components, as well as all parts for integration in the landing gear, have been designed, manufactured and tested. DO254 and DO160G requirements have been considered for design issues and experimental verification of sensors properties. Results of batch 1 have shown a very reliable design: Most of the requirements concerning electronic properties have been fulfilled already at this stage. Mechanical and overall sensing performances have been verified at tecsis by means of on-purpose test rig. The results have shown that the sensor is capable to measure the applied loads in both direction with the same quality.
Based on the results of batch 1, in batch 2 all components of the load sensor have been critically reviewed: Electronics has been improved for complying with all requirements. Load sensor inner design and fastening elements have been redesigned considering shock and vibration requirements. Clamping elements for integration in the aircraft have been optimized for improving force measurement. After manufacturing of all parts, 15 load sensor prototypes have been assembled, calibrated and tested. Results show that almost all requirements have been fulfilled, also considering environmental conditions, which have been verified in batch 2. Load transfer to the sensor has been measured on eight different prototypes. The sensor is able to measure correctly the applied load in both directions. Improvements of sensor integration could further improve load measurements results.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Load sensors currently applied on civil aircraft are few and restricted mostly to strain gauge and LVDT technologies. Future trends of aircraft architecture, like for instance more and all-electric configuration, show the need for wider insertion of these devices. Considering current state of the art of load measurements in aeronautics, the outcome of the TecALSens project provides the market a new class of load sensors based on the thin-film technology, which are not yet available. A load sensor based on the thin-film technology offers several advantages with respect to strain gauges and LVDT: precise and punctual measurement of forces, long-term stability of bonding on the hosting structure, small dimensions, high accuracy, possibility of redundant measurement, automation of production processes for high quality and repeatability of results. All this at a good maturation level, which enables a fast implementation in a real application. The sensor has been conceived in a modular way, which enables the use of the electronic also for other applications.
Deployment of more- and all-electric technical potential can fore sure take advantage of this new load sensor: load measurement represents a mandatory feature of these architectures and related systems. Load measurement in future electro-mechanical and electro-hydraulic actuators, in landing gears and in other components of an aircraft can be realised by introducing this new device. Thanks its scalability, different systems and aircraft sizes can make use of this sensor. Aircraft and systems manufacturers have now an additional load sensing possibility for designing and implementing the new systems.
Considering societal and environmental challenges, more and all-electric aircraft architectures generates a direct effect on the environmental impact of air transport by reducing fuel consumption and the amount of pollutant (less weight, more efficient on-board energy management).
These technologies strengthen European position in a strategic sector like aeronautics by increasing its competitiveness. This supports the innovation of tecsis as an SME by delivering high technical results and enabling the generation and growth of new competences and qualified jobs.

Load sensor in the testing machine

Complete load sensor