Motion Drive 3.0 - User Guide

Useful Hints

Applying and Saving Settings

On opening a Settings Sheet.
When a Settings sheet is opened for the first time, the values that are loaded are those that are saved in the relevant conifguration file. The user is then free to adjust those settings to suit.

There are then four options:- Apply Current, Cancel, Restore Previous and Save Current.

Apply Current
This applies the settings as displayed in the settings sheet to any operational runs - Manual or Automatic, but does not save them. The settings sheet is also closed, but when reopened will still display those current settings, not the ones from the configuration file. That way you can try out new settings without altering your default saved settings.

Cancel
This closes the settings sheet. Any operational runs will employ the last settings that were applied.

Restore Current
This will bring back the settings saved in the default file. The sheet remains open for further adjustment

Save Current
This will replace the settings in the default file with the ones displayed on the sheet. The sheet will remain open for any further adjustment.

Kicks & Cues

As we have discussed before, when a person is in a vehicle the motion they feel is the accelerations in all sorts of directions. These happen both when the acceleration is first applied, and also when it is subsequently removed. Try it...get a friend to drive you in a car. When they carry out a long smooth braking manouevre you feel yourself thrown forward when the brakes are first applied. Then you feel yourself thrown back again when they brakes are released. The car has not increased speed when the brakes are released - it is still slowing down, but the rate of slowing down has reduced so you feel a forward acceleration and are pushed back in your seat. So it is with, say a quick roll movement - you first feel the acceleration into the roll (the "kick on") and then when the roll stops you feel an acceleration back towards the centre (the "kick off" ) - even though the plane is still rolled to one side.

Glossary Terms

Axis Intensity

Platform Power

Reactivity

Aircraft Configuration

As with the configuration settings for individual simulations, Motion Drive has the ability to store and apply up to five different aircraft configurations for each simulation. Many of the larger simulations have long lists of aircraft for the pilot to choose from and wihtin that list are a number of diffreing aircraft types. If your platform is to provide realistic motion cues it is no point in having the same settings for a Cessna 152 as for a Boeing 747, or as for a Spitfire MkIX, for example.

And as with the simulation configuration, finding the right values for these settings will be very much a case of experimentation and a matter of feel, as opposed to hard and fast calculations. The aircraft settings page is opened from the same menu as the other settings pages.

Upon opening you are shown the page set out here. Within this section you will be able to alter and adjust three values for configuring your platfrom to perform as the aircraft, or aircraft type of your choice. Before explaining how to go about making changes to your settings, it is best to explain what the settings are and how they affect the platform.

There are three settings to consider:- Axis Intensity, Platform Power and Reactivity. The effect of these settings is to tune the intensity and speed of the platform's reaction to movements of the plane on the screen.

Axis Intensity

As the name suggests, this setting alters the intensity of the signals that are sent to the platform from the simulation. It is different from the Axis adaption setting, in that this setting affects all the signals sent to the platfrom, not according to where the platform is positioned. It also differs in that the setting is used early on in the calculations that Motion Drive carries out, and so can have a big effect on the strength of signals sent through to the platform.

As with most of these settings, there is a neutral value. In this case it is 10. Settings values higher than 10 reduce the intensity of movement. Settings values less than 10 increase the intensity. To a certain extent, the simulation will make some differences to the intensity of different aircraft. It would be a poor simulation that showed a roll rate as the same for all types of aircraft, for example. Nevertheless you will wnat to make, possibly minor, differences between the aircraft types that fly within any one simulation.

It is very much a "seat of the pants" feeling as to what will be the correct value to choose. The thing to look out for is that if the value is too high, then the platform will feel unreactive and the movements will be small and hardly noticeable, even for quite string plane manouevres. If the setting value is too low, then the opposite will be the case - the platform will feel too jumpy and twitchy, making jerky reactions to quite small movements of the plane. The right value will feel in harmony with the plane you are flying - for a large commercial airliner you would expect the feeling of smoothness whereas for a jet fighter a feeling of extreme manouevrability.

From our work, we would suggest that you might find starting values of 50 for Roll, 50 for Pitch and 20 for Heave will work for an average kind of aircraft. Bearing in mind that higher values reduce the signal strength, you may wish to begin with values higher than our suggestions and work your way down.

Platform Power

Wherear the Axis Intensity can be tuned differently for each of the axes you are using, the Platform Power works on the platform as a whole. It is expressed as a percentage and simply is a factor in calculating the strength of all the signals sent to the platform. So, a setting value of 100 is neutral, sending 100% signal strength and 50 means that signals are 50% of their original strength.

From our runs and trials we have found that Platform Power settings should be between 75 and 100. Figures lower than this simply make the platform non-responsive. So, an initial cautious setting should perhaps be 80.

Platform load
Your platform will be designed to perform to your specification at a certain maximum payload. To achieve this you will have selected a mechanical arrangement of the right strength and platfrom drives/motors of sufficient power. You will have thought about the payload of the platform and what it is made up of - cockpit, equipment and people. For most single seat simulators a payload of around 200Kg is a likely maximum.

Of that 200Kg you will have planned in that 100Kg or perhaps even 120Kg will be the weight of the pilot. However in certain circumstances, the pilot may weigh alot less than the maximum figure you have allowed for. So, the overall payload instead of being 200Kg, will possibly be 150Kg or thereabouts. The power of your motors/drives is still the same. All the other settings are the same also. So that lighter person is going to be moved around alot more quickly than is they were the full weight allowed. Under such circumstances you may feel it is best to adjust the platform to cope with reduced payload. Using the Platform Power for this is ideal, as it is a one stop setting and reduces the whole platform power - without having to fiddle around with all the other settings as well.

Platform Reactivity

This is the final setting to establish. Whereas the two settings so far in this section affected the strength of the signals sent to your platform, the Platform Reactivity setting alters how fast the platform reacts to movements of the aircraft in the simulation. Different aircraft react to pilot inputs at different rates - a commercial airliner is designed to react smoothly so as not to spill any drinks, whereas a fighter is designed to react as fast as possible.

The Platform Reactivity works by adjusting how many new signals are sent to the platform per unit of time. How fast your platform reacts to movements in the aircraft on the screen will depend on a number of factors - the power of your PC to process both the simulation and Motion Drive (plus any other applications that are running), the reaction time of your motor/drive control circuit boards (in some cases this is adjustable), the power of your drives/motors (ability to move the payload of the platform) and how well your drive system reacts to changes in direction (momentum and moment).

In most cases the power of the PC should not be a limiting factor. Our system is by no means the fastest around (1.8 GHz processor) and can process Motion Drive and MS CombatFS together with a minimum time of around 5 to 10 milliseconds. That is 100 to 200 sets of signals sent to the platform per second! In fact that is too fast for the other elements of the motor control chain, so the system has to be slowed down a little.

The Platform Reactivity is designated in milliseconds. The range permitted is a wide one, from 1 to 5000ms. What you will need to find is the right range that works for your system and then establish different settings within that range for your different aircraft. From our experience the range might be between 100 and 300 milliseconds. The higher the number the slower the reaction of the platform to movements on the screen.

When experimenting with your settings, you will notice that if the settings is too low then the platform will completely miss some movements - they happened too quickly for the system to see and react to them. Try doing some hard fast roll movements and compare the screen movement with the platform movement. If it is missing some, then another sign is that it catches the reverse acceleration without having performed the initial acceleration. (See the note about "Kicks & Cues")It will miss the "kick on" but catch the "kick off" movement. If that is what you see, try increasing the reactivity setting. If the reactivity setting is too high, then the platform will appear to be rather sluggish and unwilling to move.

Entering and Saving Aircraft Settings

The process of entering ans saving the settings is much like for the other settings sheets. First you must select a simulation by highlighting one from the list and clicking on Select Simulation. The selection will be confirmed by the message below the box. Then you select one of the five aircraft for that simulation by again highlighting your choice and clicking on Select Aircraft. Your choice is confirmed by the message shown.

The initial aircraft names are pretty dull (Plane_5 etc) so you can change the name to one that is meaningful for you. You will see the initial aircraft name also diplayed in the relevant edit box. Simply click into the edit box and edit the name to your choice.

Note: When entering your aircraft name, there is a limit of 20 characters and NO SPACES must be used within the name - e.g. Boeing_747 is OK, but Boeing 747 is NOT OK and will generate an error in future configuration.

Having entered your chosen name, then enter the settings into each box. You can then save them to the default file by clicking on Save Current or simply use them in a trial run without saving them by clicking on Apply Current. You can also Cancel out of the settings sheet without affecting either default or applied settings. You can click on Restore Previous to bring back the default settings saved earlier, providing no Saves have been carried out in between.

You will be happy to realise that you have reached the end of the settings process. You will no doubt revisit and adjust certain of your settings as time goes on, but essentially your platform should now be ready to run and begin having fun with!

Motion Drive 3.0 User Guide version 1.0