SimCENTER Hungary

Introduction

There are six models available of the Force Dynamics full motion platform.

The 301 is our original design with 3-DOF: roll, heave and pitch.

The 401 is similar to the 301 but with 4-DOF: roll, heave, pitch and yaw. It comes in three versions. The first two have 180 degrees of rotation. There is an external control mast located about 3 to 4 feet behind the machine.

The 401-AFE needs to be fixed permanently to the floor so it can't be transported.
The 401-ATE has a portable floor allowing it to be moved from place to place.

The CR-401 has continuous yaw (360 degrees plus). The computers are on board, and there is no need for the control mast.

The 302 is our most recent design. Although essentially the same as the 301, the 302 has less motion and is a smaller scale. It is 7' long, and narrow enough to fit through a standard doorway. It is lower cost than the other models, but still has the same high quality construction of the larger machines. The base system comes with Logitech steering and pedals and Logitech sound. A display is optional and can be either fixed or integrated with the motion.

The 201 has based on the 302 but has only 2 axes: roll and heave, and the sheet metal nose is optional to keep the price down.

Two computers are necessary to run these platforms. Using only one computer to control both game software and machine control software can have negative effects on the quality of the motion. In addition, high performance gaming computers can sometimes be unstable so having a separate computer, built for reliability rather than speed, control the hardware improves stability and makes troubleshooting easier.

These platforms support Windows-based software and many off the shelf games like NASCAR 2003, Live for Speed, Richard Burns Rally, rFactor, GTR and GT Legends. We now support iRacing, Dirt, Dirt 2 and Grid as well. As new software becomes available we will be adding it to our list. We do not support X-Box or PlayStation software at this time.

Both the 301 and the 401 can be modified for use with MS Flight Simulator and we also offer a model that can convert back and forth from flight to drive mode.

Any of our platforms can be modified or customized depending on a customer's requirements.

Design Life

The design life calculations were carried out using strain gage data from a prototype motion base carrying an 81.6 kg (180 lbs.) passenger and being driven by motor racing simulation software. All bearings and the structure were examined both for peak loading and fatigue life. Our B10 design life estimate is 5,000 hours minimum under these conditions. (At 5,000 hours of use 10% of the units will have failed.)

Safety

All known single point failure modes that can cause passenger injury have been eliminated. Barriers have been put in place to prevent passenger access to pinch points while he or she is belted in place and the door is closed. If the door is opened or the seatbelt unlatched the machine immediately stops.

A pair of power control relays with their NO (Normally Open) contacts in series and supervised by an electronic safety circuit supplies power to the servo amplifiers. In the event of contact welding the machine will not start. This condition is detected by the software and the operator is notified. An E-stop switch that is accessible to the onboard passenger is provided. Connections for remote E-stop switches are also provided.

Controls

Connection to a remote control PC is via a LAN. The customer can have complete control of the platform at the motor control level. The Galil DMC 21x2 / 21x3 manuals and programmer’s reference can be found at www.galilmc.com. Force will supply the needed I/O map to customers that wish to write their own control software; see ‘301 Software Interface’ for more information.

Custom Modifications

The load capacity and the performance specifications are based on the use of the motion platform as a driving simulator. Within limits, increasing the mass of the moving group simply decreases performance. When the servos use 80% of their continuous torque capability to support the static load (approximately 363 kg / 800 lbs. total), the dynamic performance is reduced. In some applications, such as some fixed wing aircraft simulations, this is acceptable.

If the platform can be powered from a 240V 20A branch circuit then the alternative servo drives can double delivered shaft power. This can allow more weight to be carried, but platform stresses, service life and fatigue, rather than motor power, will then limit performance. The design can be scaled to use double or even triple standard servo power, but costs will rise rapidly as more production parts are discarded.

When selecting components to be fitted to the motion base, weight is a primary concern. The location of the added mass relative to the rotation axis is of primary concern with respect to pitch performance. For example adding heavy LCD panels well forward of a line connecting the side struts will increase pitch inertia and as a result reduce pitch acceleration. Because of the many tradeoffs involved, we recommend that Force Dynamics engineering carry out the fitting of custom controls and displays. If the customer chooses to fit the controls and displays themselves we can provide any engineering assistance required.