Active vibration isolation with Bilz AIS™
The AIS™ consists of a PLC, CAN-Bus, 16-bit controllers, High Speed electro-pneumatic servo valves and BiAir® membrane air springs and/or HAB horizontal air springs. A range of sizes is available for both the vertical and horizontal air springs. One 16-bit controller and one High Speed electro-pneumatic servo valve is used for each air spring or group of air springs. The AIS™ works with a minimum of 3 groups (degrees or freedom) to a maximum of 6 groups (degrees of freedom).
The 16-bit controller can be mounted directly to the air-spring itself or to the machine, in the same direction as the isolator motion. Located inside the 16-bit-controller is a microprocessor, a position sensor (resolution 0,2 μm), an acceleration sensor (resolution 8 μg) and an air-pressure sensor (resolution 0,2 mbar). The signals from each of these sensors will be sampled at the rate of 4 kHz. Since each 16-bit controller has a microprocessor with specially developed control algorithms along with a special high dynamic pneumatic servo valve, the resulting performance is a very efficient real-time control and no feed-forward signal is required.The 16-bit controllers are connected by a CAN-BUS to the PLC. The PLC can be connected to a PC by a standard RS-232 for initial set-up and diagnosis. The primary function of the PLC is to manage and watch over the 16-bit controllers. In addition, the PLC has digital inputs and outputs, for example Ready, Motion Complete, Inspection of Position, Pressure and Power Supply, Switch over from Scanning Mode to Loading Mode, Emergency Stop.
The PLC also provides the possibility to switch from scanning mode to loading mode by using a digital I/O. The PLC takes care of downloading all of the necessary parameters to each 16 bit-controller to achieve the two different modes. The advantage of providing two different modes is that the performance of the system can be optimized for each mode. For example, during scanning mode when the machine is performing sensitive operations the system should be very soft and not aggressive. Otherwise forces created by the isolation system can affect the machine performance. During loading mode, level accuracy and shortest possible settling times are the most important factors and a very stiff, fast and aggressive system will provide the best performance.
- Active electro-pneumatic vibration isolation with up to six degrees of freedom.
- Highly-effective isolation of vibration without resonance amplification.
- Optimal positional precision in both the vertical and horizontal direction. Minimal deflection and subsidence times when machine changes loads.
- Highly-effective real-time control. SPS, CAN bus, one control unit for each degree of freedom and a highly-dynamic proportional position valve.
- Each control unit has its own processor and an integrated, high-resolution sensor for position, pressure and acceleration.
- Easy-to-use, intelligent WinSNI software for operation and diagnostics.
- Simple digital switching between scanning mode (during sensitive machine operations) and loading mode (while machine load is being changed).
- No feed-forward signal required.
- In contrast to electro-magnetic actuators or linear motors, no generation of heat or magnetic fields which could disturb machine operation. Consumption of electricity is held within normal limits.