The key expertise for control systems
We have expertise in development of control systems for running complex testing processes. The development requires expertise in
- real-time control,
- servo hydraulic control,
- sensors,
- electronic interfaces,
- software.
Our expertise in multi-discipline engineering (control technology, electronics, software programming, mechanics, structures) is the key of the development.
Why real-time control?
In control of an experiment where time-depending physical quantities are involved, the physical phenomenon should be reproduced in real-time manner, meaning to be exact at the same time scale with the real physical world. For example, control systems for inertial forces, inertial moments and nonlinear damping forces in vibration systems (dynamics of actuators, vibration of specimen in considering mass effects, nonlinear dampers, etc) are examples of the need of a real-time control.
Real-time control of servo hydraulic actuator for testing
In a real-time digital control system, all tasks perform their actions with an time accuracy in level of a clock pulse which counts the time in the system. Real-time controllers have their accompanied real-time operating systems that allow developers to code their real-time applications.
Real-time control of servo hydraulic actuator for testing satellite
Our real-time control solution
A typical real-time control system integrates
- a real-time digital control hardware,
- actuators,
- sensors,
- electronic interfaces,
- and more important, an advanced control program which is programmed on computer and runs in the real-time hardware.
Based on the advanced real-time control hardware NI RIO (National Instruments) and ADwin (Jäger Computergesteuerte Messtechnik GmbH), we provide customized complete control systems for measuring, testing and control. This includes
- provide solution for the required control system,
- select appropriate digital control hardware,
- select the necessary instrument of sensors, signal conditioners, signal transmitters, adapters, etc.
- integrate components,
- customize a real-time control software for the specific application.
Being efficient for most of real-time applications, our real-time digital control solutions have great features:
- wide range of available performance capabilities,
- wide range of available hardware modules for different inputs and outputs,
- highly precise in real-time control,
- highly reliable in system performance,
- excellent technical supports from the manufacturers,
- cost effective.
| Real-time platform |
Number of closed loops |
Inputs | Outputs | Control frequency | DAQ channels | Features |
|
ADwin cRIO |
1-64 | Types: IEPE, strain, LVDT, variable resistors, voltage, current; ADC: 14 , 16, 18, 24 bits | Types: voltage, current, relay, digital;
DAC: 14, 16, 18 bits |
typical frequency: 10 kHz – 20 kHz (max. to 100 kHz) | 1-256 | complex systems, multi control loops, adaptive and smart control |
Our real-time control system can control either hydraulic actuators (servo hydraulic actuators, multi hydraulic actuators, hydraulic shaking tables, our distributed servo universal testing machines) or electrodynamic actuators (modal shakers, large electrodynamic shaker systems).
Hydraulic actuators can provide large ranges of forces, long displacements at relatively low frequencies (DC to hundred Hz or lower). Hydraulic actuators are commonly used for dynamic tests of structures under traffic loads, wind loads, earthquake loads
For dynamic tests of mechanical components or satellite in aerospace and defense engineering, a wider range of frequencies (up to 2 kHz or 4 kHz) is usually required, thus electrodynamic shakers are used.
Such fast real-time tests require that the real-time control loops running at high frequency (eg. higher than 10 kHz, at least five times higher than the considered frequency 2 kHz) like our control solution which can be higher than 100 kHz.
