About the Platform Perturbator

"The Earthquaker" in room A2-105

Knud Larsen Last update: 25-jun-12 14:41

Note: Only if you accept and comply with the restrictions of use, then you can use the perturbator.

The perturbator was specified and developed by Johan van Doonik ao. in collaboration with Serman & Tipsmark in Brønderslev, who constructed all mechanics and hydraulics. The first test experiments were performed in the spring of 2003.

The picture on the right shows the platform while still above the floor. The base of the moving platform is a 4cm plate placed on top of four hydraulic cylinders - schematics are available at the end of this documents.

The cylinders are powered by a pump placed in room A2-111 (image left).

The system is designed to run at a pressure as high as 300Bar. At the present the working pressure is approx. 200Bar. The perturbator is still very strong and must be handled with great respect!

The basic system is controlled by a PLC placed in the cupboard on the wall next to the pump.

The real control of the movement of the perturbator is handled by a dedicated PC next to the platform in room A2-105.

The software (developed in-house) running on this controller PC is based on LabVIEW Real-Time and offers remote control capabillities to Mr. Kick II, running on another computer in A2-105.

The range of motion is presented in this visual guide.

Original Specifications

Degrees of freedom	:	4; X, Z, α, Β (as seen from schematics below)
Platform Area	:	0.7 x 0.6 m
Max. load	:	200 kg incl. person (subject) and force plate
Range, X-translation	:	±10 cm
Velocity, X-translation	:	1.04 m/s
Range, Z-translation	:	±10 cm; Implemented: +10, -8.5cm
Velocity, Z-translation	:	1.8 m/s
Acceleration, minimum	:	104 m/s2
Range, α-rotation*	:	±10°
Velocity, Rotational	:	200 °/s

^* Β-rotation was actually not formally specified, but expected to be the same as α-rotation, ±10°; implemented ±3°.

Cylinder position, schematic

System overview, under cover (seen from east).

Cylinders in neutral position, ie. platform flat at floor level (seen from east).

Top view.