Ate AEROTECH’s HSDA system is designed for taking high‑speed and/or high‑stability measurements from wind tunnel balances (both internal and external types) and has proved to be very popular in a variety of applications
Originally designed for capturing reliable, repeatable, clean (well‑filtered) data at speeds of up to 300 Hz on a 6‑axis balance, this capability has also allowed the filtering system to accurately track and stabilize data with highly dynamic elements, with even extreme examples such as an aircraft model under stall conditions. The system is being used in both commercial and research environments, and has made possible a recent study into the dynamic behaviour of road vehicles.
The data from each wind tunnel balance axis is captured at 4.8 kHz (with 24-bit resolution), and is then passed through an intelligent filtering system, with several independently adjustable parameters for each individual channel. This allows clean data to be produced at rates between 1 Hz and 300 Hz, selectable by the operator.
The system builds on the latest version of ATE’s Digital Signal Conditioning Units (DSCUs), and adds a Management unit (DSCM) which can drive these devices (using specialised communication hardware) at much higher speeds than was previously possible, and sends a continuous data stream to the balance or tunnel control system over a dedicated Ethernet link. The DSCM also enables the tuning of the DSCU filters to be controlled in detail.
Two cases of users who have been making good use of this detailed control illustrate the range of capabilities of the HSDA system, and show why users are delighted with the results. In one case data taken under very difficult conditions has been tamed to produce results with excellent stability and repeatability, and has also enabled the measurement times to be substantially reduced without losing these benefits. In another case, an older weigh‑beam balance has been upgraded to use loadcells, and has been fitted with the new HSDA system. Using the new configuration, data has been collected during continuous sweep motion, and has again proved to have repeatability very close to the static resolution of the balance. Results have proved to be in very good agreement with earlier measurements, but can now be completed in a fraction of the time, making substantial gains in tunnel productivity.
There is serious interest also from the Formula One arena, but here the scheme can be taken further and combined with ATE high‑speed continuous motion controls, for synchronized positioning and data acquisition. This not only provides for very rapid collection of results, but also enables some new kinds of work to be undertaken.
HSDA is available for retro-fitting to existing balances, and is now the primary system offered with any new ATE balance.
If you might have an application for the HSDA system, ATE will be very happy to discuss it with you, and to provide technical details and references. Although we have not at the time of writing been released to publish details of the two specific cases outlined here, both of these clients (and others) are in general very happy to talk about their experience with the new Aerotech system.
Summary
The HSDA system has been developed due to demand from wind tunnel users wanting to move towards high speed data sampling to enable them to:‑
- Take data in real time to see high frequency effects.
- Take data during continuous sweep movements.
- Take data during contoured moves, with precise timing.
- Sample data quicker for better productivity.
- Remove unwanted frequencies, such as those due to harmonics in a spin rig.
In addition, we have found that the system enables unwanted frequencies and noise to be more accurately smoothed out, and at much faster rates than can be achieved with simple averaging.