To facilitate the extensive performance, qualification, and mitigation testing carried out on components before they are applied or used on operational aircraft, Comar Fluid Power designs and engineers an extensive range of test rigs for the aerospace industry. These are managed through the use of control systems, which are generally bespoke and range from high-level machine sequencing to low-level time-critical closed-loop control and data acquisition. Comar works with its partner Computer Controlled Solutions (CCS) to provide these solutions.
Using design tools from National Instruments (Compact RIO range) and labVIEW, along with high-level programming language, they create modular, maintainable systems with a user-friendly interface. Their design approach is highly flexible and can lead to cost savings.
Typical Test Requirements
Standard tests carried out on, for example, an electric motor and clutch assembly that is used to control the wing surfaces of an aircraft, include: running the motor; applying resistive torque profiles; emulating typical load patterns; back-driving the motor; and applying various torsional-impact stresses.
Typically, a programmable logic controller (PLC) or computer may be used to run the various tests, linked to a magnetic-particle brake or loaded by a hydraulic motor or electric servo motor. A servo PID controller or motor drive is then used to apply the speed and loading settings. It would be normal to see a control system leading to control electronics and on to actuators. Signals would then be returned for measurement and control from transducers – torque, pressure, and velocity, on to signal conditioning, then to the acquisition system where it is mirrored (buffered) to calibration monitoring points.
Comar and CCS, together, use a systematic approach to keep it simple, using off-the-shelf (OTS) proven technology and minimising the number of brains. The inherent complexity of any machine is usually enough to create a list of problems without adding to it a multifaceted systems design. The use of technology plays a very good part in maintaining this aim.
As recently as five or six years ago, OTS became a nice idea but, unfortunately, there tends to be the occasional transducer, unique operation, or control that would best be solved with a unique PCB design or extraordinary wiring method. In addition, a mix of technology and a mix of suppliers can lead to future service issues. However, with the joint expertise of CCS and Comar, this is kept to a minimum.
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