The Control System for a Vibration Exciter

Abstract

The paper presents the control system for an electro-hydraulic vibration exciter. A vibration exciter is used to carry out kinematic and forced excitations. Such excitations are needed during the static and dynamic examinations of suspension assemblies and their elements, such as damping springs. The most important elements of the exciter are: a hydraulic servo valve, a hydraulic actuator, a control system and a hydraulic supply station. An inductor works in a negative feedback loop. A set point generator and controller are parts of a real-time control system. The authors used a cRIO-9022 industrial computer from National Instruments analogue input and output modules. Apart from supporting I/O modules, the cRIO controller in a real-time system communicates with an FPGA circuit that forms a control loop. The use of an FPGA (Field Programmable Gate Array) allowed for implementing a hardware control loop through a vibration exciter, as well as other control loops used in the research (such as controlling an active executive element). The use of such a system architecture enabled the parallel operation of multiple control threads. The selected structure also allows for flexible selection of the measuring channels, which are essential for system monitoring and data acquisition.