Showroom Driving simulator building tutorial 3DOF heave axis

[Tuto] Driving simulator building tutorial 3DOF heave axis​

Guide implementation by Momoclic
Updated 12/01/17 (Preamble)

Vous pouvez trouver le texte original en français ici

I DO NOT HAVE ANY COMMERCIAL LINKS WITH ANYONE
Preamble
It should be pointed out that in no way do I have commercial ties, or any other kind, with the companies involved in this subject. They are used as examples or because their proposals seemed interesting to me. In no way do you have to call on them to achieve the object of your dreams by using this tutorial.​

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Table of Contents

• - 1 - Introduction
• - 2 - Objectives
• - 3 - Principles of Operation
• - 4 - Means
• - 5 - Installation
• - 6 - Now to work
• - 7 - Options and variants
• - 8 - Linking mechanical computer

- 1. Preamble

After studying various possibilities for implementing a driving simulator with three degrees of freedom (3DOF) we will give you some keys to carry out his execution at the lowest cost.

What we propose is only one example, there are many other ways. The chosen method aims to make it simple, efficient and economical. The choice and quality of the components has been achieved by retaining those offering to us the best quality / price / performance.

Also note that using wood is an economic formula. However, such a simulator that sailed over a kilowatt engine (1.5 hp) generates many vibrations and stresses. Considering these facts, it is easy to understand that a steel structure will be stronger and more durable.

The construction of the simulator does not require special skills or special tools. However a minimum of tools (
see the list below) and know-how in the field of DIY are needed. In no way we can not be held responsible for anything, in case of misuse or accident. You build this simulator at your own risk.
The primary purpose of this guide is to give you some ways to entertain you.

To these must be added the electricity, which prompt us to recall some minimum safety concepts. It will be for you to imagine and implement these concepts. These indispensable parades, if not mandatory, will help protect your family from possible accidents, your friends and yourself:

• Grounding of the structure and metal parts
• Of always accessible emergency stop button (type "punch" recommended)
• Protection of rod-crank mechanisms
• Avoid walking around with loose clothing near the connecting rods and cranks
• Release the proximity of your material and prevent young children from approaching
• Ensure the quality of the connections (bolts, welds, wiring, connections, etc.)
• Before commissioning the system, check all
• Monitor, regularly lubricate and maintain the condition of your machine

- 2 - Objectives

Carry an automobile driving simulator, airplane, etc. 3DOF kind of manager swell (vertical translation). It is useable with interfaced PC games for this.
The degrees of freedom driven by electro-mechanical:

• Roll (effect "roll")
• Pitch (effect "pitch")
• Swell (axis "heave")

Other degrees of freedom will be produced, simulated by artifices managed by the software. These movements will be added, or not, to the axes or effects of the simulator to try to feel what the machine can not do by design.

Degrees of freedom (DOF) axes and effects
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One of the most effective ways to manage the degrees of freedom is to motorize using cylinders. The form of energy easier to implement for the amateur is electricity. There are electric cylinders but these are expensive or difficult to achieve. For these reasons, we will use for this building the SimuKit 3DOF 350w with 70mm crank arm length. The electric motors will replace the cylinders using a connecting rod-crank system. This system has the advantage of being economic to the drawback of not providing a constant speed of vertical movement of the connecting rod. However, experience has already demonstrated the effectiveness of the mechanism.

In the kit we have, among others, three gear motors that rotate at 60rpm and provide 45Nm consuming 350 watts each.

To animate our games and our simulator we recommend the use of SimTools. This software runs on the same computer as your games and pilot the simulator via a single USB cable. You will find this program and explanations about " www.xsimulator.net ".

About our stops at the design and implementation of the mobile platform of the simulator and its engine. This means that anything that is likely to be installed and attached to this plateau is to imagine and design by you. We just make a few comments and recommendations thereon.

The main features of 3DOF simulator that we retain for this achievement:

• Tilt angles involved: + 10 ° (20 °)
• Rotation angle of the cranks in game: 120 °
• Cranks with 70mm arm length

Note: For security reasons, to avoid any breakages, cranks have the ability to rotate 360 °.

- 3 - Principles of Operation

Although the following description fits our project many of the principles discussed are applicable to other types of flight simulator.

The electro-mechanical part:

The maximum angle that can hang this 3DOF is determined by the inclination of the seat plate. The movements of this plateau here exclusively vertical, is provided by three connecting rods-crank teams. Each of these rods calipers is driven by a gear motor with worm and both directions of rotation. In a sense, you go up the other goes down. The high ball three rods form an equilateral triangle. The rotation of the motor raises or lowers the rods independently of each other. Each connecting rod is linked to one of the triangle points and according to its movements inclines more or less the tray. If all three engines up or down together we obtain the vertical effect. The combination of movements of these three axes allows us to simulate, in part, the behavior of a vehicle.

The electronic and computer part:

The movements of the simulator are calculated using information provided by the game running on the computer and communicated to management software simulator (SimTools). The latter, through the USB port, information map controllers. The controller card (Arduino) drives the gear motors "in position" using the power cards (Sabertooth). The potentiometers inform the controller board on the position of each motor. During the course of an action, according to information received from the game and those received from the potentiometers sending a controller board position correction signal to each of the motors concerned.

The axis with 3DOF heave:

In this concept, the levitation of the movable part of the simulator is provided, the kinematic point of view, for an equilateral triangle. At each of the points of this triangle there is a mechanism, over a limited travel, of lowering or raising the platform.

• If the three mechanisms working together, as the case, the movable portion rises or descends. We run here, and the axis "swell".
• If both mechanisms are stationary and the other one is, then the platform tilts and generates, according to the activated tip of the triangle, an effect of "roll" and "pitch".
• If a mechanism is motionless while the other can move independently from each other upwardly or downwardly, we thus have another means to cause angles taken. In this case too, the effects of "roll" and "pitch" are activated.

Notes that with this system we are able to take a same inclination angle of the 360 ° of a circle on the horizontal plane

- 4 - Means

Composition of SimuKit 3DOF 350w ( Kit developments might you find here )

• 3 Geared worm 350W
• 2 Cards "H bridge" Sabertooth 2 x 32 amps (which leaves the possibility of adding, for example, another motor for the yaw effect!)
• 1 Power 24 Volts 42 Amps
• 3 Potentiometers FCP22E
• 9 female heads M10
• 1 micro-power controller Arduino UNO R3
• 1 USB 2.0 cable 2.5m
• 3 sprockets 50 teeth
• 3 gears 20 teeth
• 2 AC Power Cords
• 10 son Arduino connection
• 1m shielded cable

SimuKit option

• Cranks 6-pitch 70mm

Equipment List (dimensions and quantities are adjusted according to your project)

• Panel mobile plate (against-plated 20mm) 0,625mx 0,720m
• 20mm socket panel: 0,690mx 0,790m or according to your option 0,790mx 0,900m
• Battens 40mm x 45mm x 440mm: Engine Support-wedge (x3 + 1 = 2m)
• Sheet 2.5mm 55mm x 160mm: Support-motor (x 6)
• 20 x 5mm flat iron cross anchor: Support engine (2x3 = 0,400m)
• Tube Ø 20 to 30mm X615: triangular Brace (x3 = 2,000m)
• Ø 14mm tube: connecting rod reinforcement (x6 = 1,000m)
• Square tube 25x25x2 (minimum): Rod (x3 = 0,800m)
• threaded rod Ø 10mm 200mm: Rod (x6 = 1,200m)
• Screw M8x60 partial thread: cross axes (x6)
• Bolts M8x60 (x15)
• Bolts M8x80 (x10)
• M10x40 bolts (x6)
• M10x50 bolts (x3)
• Wide washers Ø 8
• Ø 10 washers
• Lock washers Ø 10 (x6)
• M8 nuts
• M10 nuts
• son 2,5mm² electrical supply power engines
• electrical wiring son 1,5mm² other potential
• Support potentiometers (x3) (to manufacture an insulating material preferably)

Minimal tooling list

• Wood saw
• Metal saw
• Drill
• Wood Drill Bits
• Metal drill bits
• Vice
• Screwdriver Set (flat, Phillips)
• Set of keys (10, 13, 17 ...)
• Soldering iron and tin (solder)

And also some physical bases of mathematics and geometry

Why 70mm cranks?

We have engines with a torque of 45 Nm. To turn a couple power to consider the distance in meters from the center of rotation of the weight lifting

• 45 Nm / 0.07 m = 642.9 Newtons

To convert Newtons to kilograms we take into account the gravity (the gravity)

• 642.9 / 9.80665 = 65.55 kg

This means that only one gear motor when its crank is horizontal, is able to lift more than 65 kg. These calculations call has a static, while our simulator is at the opposite of this notion, our machine is dynamic. The dynamics takes into account the inertia and acceleration of masses in motion. We have the best role we do not know what constitutes the mobile part (steering wheel, screen (s), etc.) or their distance from your building's center of gravity. So there we is not possible to make these calculations and it's good, these calculations are quite complex, so you will spend like all of us.

Experience shows that an approach on static bases gives acceptable results from the time or are exploited that 2/3 to 3/4 of the calculated maximum load. More motors, by the operation of a simulation, are not constantly fully charged even if sometimes peak, they pass overload.

Vertical displacement obtained with 70mm crank arms

• 180 ° (twice 90 °) twice the crank = (2 sin (90 °) x 70mm = 140mm
• 120 ° (twice 60 °) it is as simple = (2 sin (60 °) = 121.2 mm x 70mm

In this example you notice that for the same race, simply lengthen the crank 60 to 70mm when going from 180 ° to 120 ° of rotation.

Differences between 180 ° and 120 °​

Choosing between 120 ° and 180 ° rotation of the cranks

- Perhaps you notice the undeveloped part, between 120 ° and 180 °, in the rotation we lost relatively few stroke (14%).

- A 60rpm time to travel a half rotation (180 °) is done in half a second.
At the same speed, the 120 °, the third tower is carried out in 1/3 second. Either 1/3 time less that 180 °. That is, with this angle of rotation, and the appropriate length of the crank, the same stroke will be covered in substantially less time.

This time saving motivates us to adopt this option, and we will have a much more efficient and responsive simulator. However please note that it is only possible to the extent that it has sufficient torque, as we have seen above.
Either two arguments to operate without regret this angle of 120 °.

Angle calculating inclination of the movable platen

mobile tray settings
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If one drives a single motor up on the triangle formed by the three upper rods anchors (tray-seat) tilts the axis of the geometric height of the triangle by using the two pivots as axis of rotation.

Rather one can keep a single fixed point and operate two engines. There are two possibilities then:
- Two engines are going in the same direction which amounts to almost the same as the previous case.
- Two motors rotate in opposite directions, the movement is on the half side of the triangle, shorter than the height and the same amplitude which increases the inclination angle with respect to the first case.

The most important angle is the one generated for the same race by the shorter lever arm. We retain the latter for our calculations. The ball we have does not accept more than 13 ° inclination from their central axis. For security reasons we will only use 12 ° to deviate slightly from the limit and offset some still possible execution errors.

The two elements at our disposal, and are part of our objectives are the 70mm stroke and angle of 12 ° whose sine is 0.208. Calculate the hypotenuse that results.

• 70 / 0.208 = 336,7mm

Calculate the side of the triangular platform
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This rating represents the half-way between two balls of axes. This is also the next half of our equilateral triangle, which makes us a triangle whose side measurement 673,4mm.

Calculate the height of the triangle using the tangent 30 ° = 0.577.

• 336.7 / 0.577 = 583,5mm

Triangle lift
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And the position of the center of the circle circumscribed to the triangle meets the middle and mediating, located at two-thirds the height of the equilateral triangle.

• 583.5 x 2/3 = 389mm is the implantation of the mobile platform radius.

Calculation of the base implant

Before embarking on the final implementation plan two possible positions for each of the engines. We take as a rule of mounting the crank-connecting rod system which guarantee symmetry of movement on 180 °, it is in survival hinges here.

Engine position
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The case for reducing motors, side view, appears briefly as follows:

Gearbox output shaft position
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Note the 51mm dimension, the end of the gearmotor, it will be helpful to draw the circle site on the support base.

As you can see, the second mounting image "Motor Position" allows us to gain 70mm on the swing radius of our simulator.
So we can draw a circle implantation simulator of the base using the information from the two previous drawings.

• 389 -35 + 51 = 405 mm distance from the center of the circle outside the discount boxes of our engines.

- 5 - Installation

We chose a location of radial engines, each branch is located at 120 ° from each other. In this configuration it is necessary to determine the front and back of the simulator. A simulator says "all mobile" square wheel, pedals, various levers or screen (s) on the front of the machine. These elements are relatively distant from the center of gravity and induce thereby significant inertia. To fight against the inertia we are going to cooperate together a pair of three engines at our disposal.
All these reasons that guide us to place a single engine at the rear and two forwards.

To carry out the layout we need essentially a single value: the radius of the circle positioning of the upper ball joints: 389mm.
This value is extrapolated others including that of 405mm extreme position of the gearbox on the star of the stand.
The height of the engines on the star is determined by the length of the cranks.
Another important dimension to be checked imperatively conditioned by the circle, the distance between the axes of the upper ball joint 673,4mm the side of the triangle.
All these values determine the position of the elements, but not the space outside.

Unit dimensions

To consider exceeded cranks and hinges outward and the spacing of the rod bracket.

Unit dimensions
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The pairs of cranks, 198mm apart to-center, equipped with two ball joints protrude outward on the axis of the limb of the star. They also overflowing laterally to this axis, all this determines the outer boundary dimensions.

Dimensions top view
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Result of this analysis, the base must always be at least 0,690mx 0,790m. This size does not account for a possible background, it ensures the construction and stability of the system.
To dress the unit must, for example, add to this format cleats to protect rods and cranks. These cleats should cover the same area as the large format.
The large tray that allows external protection directly attached, must measure 0,900mx 0,790m. Amounts panels are placed and bolted to the outside edges.
In summary, the final dimensions of your project will be one of the largest panel to which you add the thickness of the side panels.

- 6 - Now to work

Some recommendations

The forces applied by these engines are important:

• Prefer the plywood to the medium, especially for the mobile plate and apply yourself to stiffen the maximum every room.
• Consider the material sections as minimum, in general there will be no problem to use a slightly higher dimension.
• Wood trays are advantageously stiffened firmly bolting reinforcements (the seat slide rails, for example) and by placing large washers against the wood.
• It is possible to stiffen the set screws with a tubular casing for added strength.
• Tighten the fasteners and assemblies, firmly and without excesses, against nuts or lock nuts are sometimes indispensable.
• Secure the cables, do not let them hang, hang or exceed.
• Remember also that a single misplaced or a hole saw primer, whatever the material, can seriously weaken a room and consequently your simulator, or even cause an accident.
• Periodically check all clamps and lubricate the ball after a few hours.

One such work, at your fingertips, requires a minimum of rigor!

Tracing is the fundamental operation of realization. Its quality will depend on the angles it will be possible or not to achieve.
A positioning error of the simulator components can have dire and destructive consequences.

Base route

The route must be made directly on the 20mm panel. Minimum size is 690mm x 790mm in orange colored images.
If you make a metal tube construction, use cardboard to make this layout.

The goal is to draw a triangle whose points allow to position the gear motors.
The simplest way to draw a triangle in a circle, first draw a hexagon.
Your memories of geometry are too far? Then try the web is full of examples and videos.

If you do not have enough large compass, take a tip you will sink slightly at the location of the center.
Attach a pencil to a piece of string, then the other end, loop the right length and hook the loop at the tip.
It'll just draw.

Plot simulator base
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Draw the triangle with rules and medians mediating since we are in an equilateral triangle.
In fact, you can use a larger pan, for against the important things are to respect the position and route of the triangle.

Note: The orange area represents the minimum size of the plate. The light-green part can be useful to place the power supply and electronics, it can be increased without inconvenience. Sidebands, dark-green, delimit the space for a full lining that protects the movement of cranks.

Now we will plot the location of the three engine mounts. Arranged in a star on the center median.
Draw to 22mm, from both sides, two middle parallel.
Draw outside of the triangle points in a straight line parallel to the opposite side, the center distance of 445mm. At the back it's easier since we are on the edge of the plate.

Layout of motor carriers ​

The media gearmotors

Each of the branches of the support star is composed of a wooden parts, and two sheet steel 2.5 or 3mm.

Shims

At the center distance of 70mm must be added at the end of the crank 10mm material and safety we keep ten millimeters reserve. This places the output axis of the gear to 90mm above the base. The output shaft is 50mm from its base: 90 - 50 = 40mm thick to remember for wedges that allow cranks browse through 360 °.

The three necessary pieces of timber have the dimension of 45mm x 40mm to 440mm long, they serve both to raise and fix the engines.
Note the line on these parts "engine placement Bookmark", 40mm of the outer end that serves as a positioning gear motors.
All holes have a diameter of 8mm.

Above a wedge engine mounts ​

Note: Remember to identify the position of the end reduction boxes to 40mm from the tip of the branch of the star. The exact width reduction case is 44mm. There will be no problem to use a piece of wood of 45mm that has all the chances of crashing when tightening between the two metal plates. The height of 40mm may be modulated according to the length of the cranks used.

Fixings

The side decks are made of sheet steel minimum 2 to 3mm thick. By engine, so each branch, it takes two. What makes us six sheets of 55mm x 160mm.

At the center distance of 70mm must be added at the end of the crank 10mm material and safety we keep ten millimeters reserve. This places the output axis of the gear to 90mm above the base. The output shaft is 50mm from its base: 90 - 50 = 40mm thick to remember for shims.

Engine mounting plate
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Note: Holes reduction housings fixings are drilled home to 6.5mm. For several reasons we recommend boring, using a drill three 8mm holes. The case is aluminum this does not pose any particular difficulties. You can opt for galvanized brackets, well sized, trade. Plan well the appropriate mounting holes and think that all must ensure excellent longitudinal and transverse rigidity.

Description of attachment

It is possible to use galvanized angle bracket found in hardware stores. The dimensions are very variable, hold only that they must have a go from a minimum of 60mm. Prefer a model sheet of 2.5mm. Feel free to ask some wood screws into the holes available in addition to M8 and their large washers. Below an example that score that important heights, other dimensions depend on the characteristics of the design found.

Fixings brackets ​

The tubular reinforcements

To lute against the transverse effects, and other jolts vibrations, it is prudent to ensure system stability. The links that we will establish must be perfectly rigid. For these reasons we must spread the flat iron that is not appropriate. For simplicity of implementation we chose to use the minimum 20mm diameter tubing. An angle could have been suitable but requires access to the weld.
To manufacture these reinforcements you need three tubes of 615mm. Using a pen and a ruler, draw a line on the side of the tube. This feature allows you to align the two ends to flatten. To locate or pinch the ends draw a circle around the tube to twenty millimeters from each end.

Drawing a reinforcement
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Pinching an end of the vertical tube in a vise. Place the contour marking flush upper jaw and the vertical line you have drawn equidistant from both jaws. Then tighten the noose being careful that the tube does not rise. If so, squeeze, eg 30 mm instead of 25. In summary go gradually to crush the maximum. Proceed the same way on the other end of the tube, making sure that both ends of the dishes are on the same plane, the vertical line is there to help you.

Note: - Before pinch the tubes permanently, it is recommended to test a drop tube to see how the tube will behave. - If the quality or thickness of the tube you use causes its slot when you crush it, you can insert a piece of flat iron in the entrances of the tube. Few centimeters will suffice and remain in place. Warning, it will fold and this may require to provide a little longer screw when assembling the gearboxes.
When both ends are flat in a pinch to 20mm tip ensuring that the tube is perfectly vertical and pull it toward you until a 120 ° angle between the flat part and the tube axis. Do this only from one end and drill a 8mm hole diameter to 10mm from the edge.

In this present progress up the tube through an M8 screw in the body of the gearbox. So check your work and possibly correct it before it is too late. This operation is called a "white mount".

If this is correct, cintrez the second end and rebuilt a new white mount. When the tube is in place, the bolt of the other motor squeezing the tube, using a felt locate the drilling axis of the second hole of the reinforcement. Disassemble and drill the second hole, checked, you just completed a brace.

At their establishment consider putting large washers to properly apply the flattened surface reinforcements against the case.

Base assembly

Mark and drill the platform by positioning with maximum precision. Note that unlike the back of the star, the two lateral branches are more difficult to place correctly. The quality of your plot is a great landmark or make you a "square" cardboard with branches of 400mm to 120 °.

End left front corner
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The base assembly is executed with bolts, large washers M8. This requires having a little space under the tray base. Luckily, it is out of question to ask the board directly to the ground. We take this opportunity to set rubber stamps a good diameter under this plate. Bolts to the star ends may agree to maintain and height of the feet provided the necessary space to bolt heads. In the gap of the star center place a bolt with a very large washers (possibly wooden) solidarisera that all branches of the star.

For this you will need 15 x 60mm M8 bolts to secure the plates. And 10 bolts M8 x 80mm to fix the holds, do not forget the large washers against the wood. The tenth bolts goes to the center of the star. You can replace the bolts with pieces of threaded rod, but then think about cutting long enough extra nut.
The tubular reinforcements, set in the upper part of the reduction boxes, using three M8 x 80mm. Think of the washers and tighten all the screws subsequently remember to check the tightening sometime after setting simulator service.

First assembly
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Note: If you have very good big feet with rubber pads under the engine, it will not be necessary to further strengthen the base.

The movable plate

The moving plate is the part that will ask for great accuracy. These are the plots of the base triangle and the moving plate that define the kinematics of your simulator. The dimensions you see have a direct influence on the range of movement and symmetry. Risks increase for non compliance ratings, then bring it very carefully.

The route must be made directly on the cons-plated 20mm to 625mm x 720mm. Start your tracing the long side of the panel which will be the back of the simulator.If you opt for a different mount that will describe below, adjust the panel accordingly.Repeat the technique used above for the base. Caution here, the circle center is not the center of shelf.
As previously are the points of the triangle that must be perfectly positioned. Before starting we must make small calculations dependent on our way of fixing ball joints.

Calculating positioning ray tracing universal joints

The universal joints, in our assembly, are placed in outer boundary of the moving plate. Their three vertical axes should form an equilateral triangle to meet the defined kinematics.Calculation of drilling ray ball fastenersFor holes we use, as always, the Implementation of Radius (389mm), the Ray Exterior Limit (RLE = RI + 10) and the ratings of our mounting brackets.

• Distance outer screws = Dve = 25mm
• Distance inner screws = Dvi = 55mm
• Outer piercing ray = RLE - Dve = 399 - 25 = 374mm
• Inner bore radius = RLE - Dvi = 399 - 55 = 344mm

Route of the mobile plate

Plot shelf mobile support
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To meet the geometry defined above, we must ensure that the balls are perfectly at 120 ° to each other. Draw the triangle and drill hoops calculated above.

Plot fasteners ball joints
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Note: Remember to identify the center of the triangle formed by the ball is in the vertical axis that must be placed the center of gravity of the mobile assembly.

The cranks

If technically make the cranks presents no difficulty out of reach of the amateur, the problem is to have a way to drill a Ø 20mm.

Fortunately Thom Concept (Rider63) in designed for you the cranks of your needs and you can acquire them near SimuKit.

If you have the proper drilling means, here are the achievement scores of these cranks using 30x30x2mm square tube. Please note that the positioning of the two 8 mm holes on the same face is important. In effect the output shaft of the geared motors is crossed by a 8 mm hole placed at 9 mm from the end. In bad hole square tube would not shake the tree. The second screw ensures, with the vis-a-vis slot, the necessary clamping the other side of the square.

To saw the gap between the two holes of 20mm and 8mm is done simply by removing the Frame saw blade and up the through hole.It takes place a very large washer in the shaft to prevent the square tube slide while tightening and under the brutal operation efforts of the simulator.

Realization of a tubular handle​

Braces universal joints

Ten centimeters of acetal sufficient Ø 30mm, cut the piece in three parts of about 32mm each.
Trace on each of the ends, using a cardboard template, a square of 25 mm side, taking care to locate an axis on the side. For this draw a vertical line on one side of the acetal round and an index on the cardboard square.Cut, using a hacksaw, the excess material by thinking about the thickness of the saw blade and keep the two parallel sides. And ensure that the cuts of both ends are well perpendicular.
Then draw and drill the 8mm holes.

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Warning axes through acetal should be smooth. Pick your 6 M8 x 45mm which are not threaded along their entire length.

Fasteners braces to the movable plate

To achieve these fixings you need about 400mm angle of 25 x 25 x 3mm. Each requires two pieces of 65mm, each pierced with three holes symmetrically Ø 8mm.

Upper anchorage of the spider​

The connecting rods

The dimensions given on the drawing are indicative. Both are very important, one is the center distance between the two rods and the other the minimum "bridge" height 160mm, it is what allows this mobile hitch pass over the housing reduction. These two rods must be perfectly vertical, spacing is determined by the cranks and three washers 2mm thicknesses necessary for the passage of spherical caps.The rods consist of two threaded rods of about 180 mm wrapped in a steel tube of 14 mm of about 120mm. They are capped by the bridge square tube of 2mm thick and 25mm side. Laying against nuts or brake nuts is essential.On the bridge is built the cross from universal joint. To achieve using the flat iron 20x5mm Ø 8mm drilled holes.

Rod bridge
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If you can weld two flat drilled a hole each, otherwise a flat U-bolt will do. Do not drill holes through the dishes once in place. To allow a better sliding of both sides of the cross inserting a large washer. We must therefore take account of this thickness and add washers between the flat bar and square tube during welding or assembly.The space under the crosspiece is important to allow the lateral angle socket without interfering with the threaded rod.You have chosen the second solution U, then think about the extra thickness under the bridge. It may require you to lengthen the threaded rods and tubing.

Size of a connecting rod
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Note the assembly of round tubes in the square tube:

Detail rod assembly
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On either side of the square tube holes are different. The top hole is 10 mm to allow the passage of the threaded rod. The lower hole, he is reamed to the outer diameter of the cladding tube reinforcement.In summary tightening is only between the end of the round tube (blue) and the upper side of the square tube (gray) is a few millimeters thick.This is important for two reasons:

• Prevent overwriting of square tube during tightening so that over time.
• Ensure greater lateral stiffness to the rod.

This type of assembly is to apply even if you weld the tubes to prevent crushing of the square tube.
Here on the 10 mm rods are sheathed in 12/14 mm tube, it can be more if you have the time it enters the square tube. In this case it will be based on a robust ring against the ball tip.
This assembly is particularly important in ensuring the lateral rigidity of the system. The threaded rods risking to flex easily in the jolts repeated simulation. If you have the ability to weld the tubes, 10 mm holes suffice.

Note: If you do not use the cranks or kneecaps kit, consider correct dimensions in the specific features of your hardware. Similarly if you use a larger diameter tube for reinforcements, this may affect the minimum height of the rods.

Assembling your simulator

The angles are simply fixed to the plate by 35mm M8 and a large washer is applied next timber. Remember to put too side nut, lock washer or range to prevent loosening.

Your future simulator​

• Different heights of the plateau above the ground:
  
  Simulation:
  - Top 430mm
  - Down 310mm
  
  Extreme:
  - 440mm High
  - Down 300mm

- 7 - Options and variants

Driving position

There is no way to assess a driving position that does not match your expectations, each with their preferences and style. However, we must consider several factors before embarking on the construction of the simulator. As you can see in the following image, depending on the length of your structure, you do not have more than ten centimeters from the ground to the front of the mobile structure.

Risk of interference of the mobile structure with the ground
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One of the fundamental rules in a dynamic system such as ours is that the center of gravity (CG) is closest to the center of rotation (CR). The rotation center of our system moves with the movements a few centimeters below the moving plate.

This rule, imposed by physics, it follows that the bottom of the bucket seat must be as close to the moving plate, attached directly to it, Avoid the raise.
So you say the only possible driving position is that of a formula, heels a few centimeters below the level of the seat! ensured frustration rally drivers ...
Rest assured the solution is simple: to extend the rods all that wish to increase the vertical distance between your buttocks and your heels. This will not alter the simulator's behavior by improving your driving comfort. Of course, this surélèvera average seat height but we start from relatively low.

Note: If you wish to 100mm between the seat bottom and the surface or rest your heels, threaded rods connecting rods will increase from 180 to 280mm and reinforcements tubes (essential here because of the risk of buckling increases with the length) of 110 to 210mm.Thus the torque required for reversal will be lower which may involve widening between the points of support on the ground ...

Support points
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An example of what it can do, the more tight, like protection with panels 10mm thick. Probably there-was-there enough space on either side of the rear motor to place the electronics and power supplies.Note also the example of tubular structure primer. Enjoy the space under the tray to lower the center of gravity by bolting the same time structure that slides here in black and possibly remove unnecessary angles of said plate. You have to figure the mobile structure that suits you. The rules being to make rigid, light and concentrate the masses as close to the center of gravity ...

The closed 3DOF​

Variations

The project we have just described is only one example. Many opportunities are available to you, all depends on the goals you set for yourself. However kinematics and physics have their intransgressible laws.

One of the selected constraints is that induced by the choice of the hinges which limit the angle taken by more or less 13 °. Know that there are ball joints that permit up to 16 °. But their nominal diameter of 14mm does not use to everyone.There is a solution which is to use "angle enlargers" with the usual ball:

http://www.25crmo4.fr/Roulements - Rotules.htm#hoekver

Corner enlargers (08/16 Rates)
​

The interest can exceed 13 ° and possibly reduce the crank is to decrease the size of the simulator. Thus it becomes possible to pass through a standard building our door. For this we limit the angles at 15 ° for mechanical safety and also reduce some piercing crank 65mm. By choosing this option it is necessary to review the implementation by referring to the base circle that goes from 389mm to 313mm. Some simple calculations will be necessary to achieve your goals, why you just follow step by step example of this guide and adapt. The implantation beam can not, must not go below 290mm.

Attention involved, the angles of inclination may be significant and will likely be limited in SimTools. The relative narrowness of the simulator will need to attach struts on the sides and back, they will eventually be folded, just like what we have done to the front of our simulator.

Cranks calculations 65mm and 15 ° angle
​

Télécharger la feuille de calcul (.ods, logiciels gratuits) qui vous permettra de penser et optimiser votre 3DOF à effet de houle.
Download the spreadsheet (.ods, free software) that allows you to optimize your thinking and swell effect 3DOF.

Télécharger la feuille de calcul (.xls, Microsoft) qui vous permettra de penser et optimiser votre 3DOF à effet de houle.
Download the spreadsheet (.xls, Microsoft) that lets you maximize your thinking and swell effect 3DOF.

Note: In summary, unless you want amplitude of movement, more congestion increases and vice versa.

- 8 - Connect the mechanical and computer

To make this work we use the two vectors that are electricity and electronics. The mechanical work produced by the electric motors must be managed to ensure the simulation. Several components are essential to achieve our goals:

• Position sensor
• Power board
• Micro-controller board

The position sensor (potentiometer)

The electric motors we use to position the nickname car is our simulator. They must quickly reach the position requested by the game and our controls: steering wheels, pedals, etc. For this we use the type of cards "H-bridge" to reverse the direction of rotation of DC motors, themselves are managed by the Arduino microcontroller. To work the microcontroller needs to be constantly aware of the position of the cranks (relative elevation rods). To this end we use pots that tell the system to the placement of the platform. The only potentiometers to retain should have 360 ° of rotation, in other cases it is the insured case ... However despite being able to do many laps this potentiometer has an active range on 300 ° 340 °.

Note: The potentiometers 360 (without stop) were chosen rather than any other sensor (Hall effect or other) for their excellent quality / price and implementation simplicity.

As you know we want to exploit the rotation of the cranks on 120 °. Turn the potentiometer shaft end of the gear motor will make us lose a lot of precision, which generate parasitic oscillations. The solution is to use gear that role will be to travel 300 ° when the potentiometer 120 ° will be driven by the crank.
We must therefore determine the transmission ratio required for our example:

Gear ratio: 300/120 = 2.5

Starting from the assumption that we have a sprocket 50 teeth to the motor calculate the required number of tooth the potentiometer:

Number of teeth to the potentiometer: 50 / 2.5 = 20 teeth

With a 50 sprocket 20 teeth torque and thus we fulfill perfectly the specifications for motor rotation of 120 ° and 300 ° using the potentiometer.

The potentiometer support

Here it is very simple to make, choose an insulating material a few millimeters thick and 100mm long by 30 to 40mm wide.

Supporting a position sensor​

Note the few tricks of the assembly, first the diameters of the holes are to accommodate you component.The tree 350w motor is 20mm in diameter. The hole is slightly higher not to force on the shaft. The top hole is 10mm but here the original gear motor casing is drilled 6mm we recommend 8mm boring with a drill. The remaining game odds allow small errors while facilitating assembly, but the wafer to be clamped between washers.
For realized the oblong hole to start with drill two 3mm holes and two 9mm and finish with a small flat file.
But in fact, why a slot?
Well, for at least two good reasons:
- To allow precise adjustment gears
- Allow a "release" position sensor in the development phase.

Remember to put a washer under the nut of potentiometer so that it is well maintained and does not slip over time.

Odds and tracing support​

The sensor mounting Wanegain​

The wiringHome, home, electrical outlets accept a maximum current of 16 Amps. To carry this current section is the son of 2.5mm². A simple division allows us to calculate the density mm²:

16 / 2.5 = 5.77 Amps / mm²

350w engines are supplied with 24 volts which requires intensity:

350/24 = 14.6 amps

As a result of 2.5mm² wire will be perfect for powering an engine. But CAUTION a Sabertooth card supplies two engines!
This will require between diet and each of the Sabertooth 6mm² wire (or failing double the 2.5 mm²).

Note: For security reasons, follow them carefully son sections to prevent overheating and loss of performance.

Cable schematics

Provisional: two engines
​

Wanegain recommend taking the 5 volts potentiometers on Ardiuno rather than Sabertooth. Indeed, in case of malfunction or power failure 24v potentiometers are always powered. So that when restarting there will be consistency in the positions of the values since they have been stored by the Arduino.

The power board (or Sabertooth Moto-Monster)

It is this electronic card that supplies DC motors (DC). It is directly connected to the low voltage supply and sending according to the instructions received from the micro-controllers the rotation orders in one direction or the other.This type of card replaces the relay since no contact. The H-bridge used to perform two functions to reverse the direction of motor rotation by reversing the current to the motor terminal and the variation of the engine speed by modulating the voltage across the motor. In addition, it allows a magnetic braking if it is able to dissipate the generated power. Indeed an engine such as those we use is called "universal" because it works in both engine dynamo.

Note: In these last remarks we can deduce that the resistors supplied with this type of card may not be necessary.

The micro-controller board (Arduino)

Now geared motors and position sensors are connected to the power cards, but are still not in communication with the game. For this're implementing the microcontroller board (Arduino). This card connected to the computer via a port and a USB cable, receives the information of the game through the simulator manager what SimTools one hand. On the other hand knobs to inform about the position of the platform. After treatment of these two types of data the microcontroller sending orders to the engine via the power cards.
The treatment that cooperate this little world is the program "injected" into our controller card (Arduino). This program receives gambling information via PC SimTools according to the information provided by position sensors directs it using the engines positioning the platform of the simulator.

The microcontroller program

Achieving a "sketch" Arduino requires some knowledge of programming and operation. If you do not have these skills Wanegain offers its expertise in the field on the site PCSHM "simtool 3 engine" that allows you to shake your achievement. For this you must have read the Arduino operating bases. You will find on the web many tutorials for you to choose one that suits you, search engines are available. Then simply "inject" the code into the card and whether you have complied with the recommendations you can begin testing full-scale ...

The PID

After the mechanical implementation of an effective position sensor, we are faced with the aspect of "real time" of the problem. Indeed nothing is instant, it takes time to reach the set position (the one requested by the game) and stabilize this position (downtime of the engine that continues more or less to run despite the current is cut or inverted). To manage this phenomenon there is a control method called PID for "Proportional, Integral and Derivative."This method does nothing complicated in itself and to understand it better I invite you to read the page from Ferdinand Piette:
Implémenter un PID sans faire de calculs !
Implementing a PID without making calculations!

Not to worry for its implementation, the software versions at your disposal on the site take perfectly into account. With this information, and others, you may be able to improve or upgrade your simulator.

Note: A good PID tuning is essential for proper operation of the simulator. It must be completely settled before embarking on the setting SimTools.

If you want to narrow the PID, Adp-sys has made a handy code generator:
Générateur de code PID pour Arduino et SimTools
PID code generator for Arduino and SimTools

Et le propos tenu par notre camarade de jeu est ici
And the remark made by our playmate is here

First lapsThe free version of automobile simulation software "Live for Speed" (LFS) authorizes the use of a plugin with SimTools also free. For this reason we encourage you to begin the development of your simulator with these elements.
_________________
Good luck !
And do not hesitate to interpellate me in case I'm not quite clear ...

Momoclic

Rédigé en français j'ai converti le texte avec "Google Traduction" j'espère que ceci sera lisible en anglais.
Merci pour votre compréhension.

Written in French I converted the text with "Google Translate" I hope this will be readable in English.
Thanks for your understanding.

Exemples de réalisation par différents constructeurs :
Examples by different builders:

https://www.xsimulator.net/community/threads/simulateur-3-dof-heave-motor-350w-24v.8358/

http://pcshm-simulateurs-homemade.clicforum.com/t932-Projet-3DOF-2-DOF-1-DOF-Wanegain.htm

http://www.racingfr.com/forum/index.php?showtopic=51621



http://pcshm-simulateurs-homemade.clicforum.com/t1010-Projet-3DOF-de-vince-129.htm

Excellent !

Bravo!
It's a thesis more than a tutorial

Merci, mais il se veut avant tout un outil pour aider à correctement réaliser son jouet...

Thank you, but it is primarily a tool to help properly perform his toy ...

Great job!

super travail

great job

Thanks Travial, I have been looking at making a stewart platform. I really enjoyed your explanations.

Awesome post. Should be made a sticky. Well written. Inspired, adaptable informative, debatable. What more could you want?

Merci, j'espère qu'en Anglais ce ne soit pas "imbuvable"

Thank you, I hope that in English it is not "unbearable"

Great work buddy, hope you enjoy it.

Bravo à toi

Like it !

Thank you !

@momoclic - Excellent Sim. I've finally had time to sit down and read the article.

You note that the given weight that each motor can lift is 65.55kg.
At a guess, would three of these motor's support a person with seat at 110 - 120 Kg??

I'm assuming the 3 motors at 65kg are not quite cumulative, more an average? What I mean by that is the lifting force is not 3 x 65kg (195kg) but more like 150kg (still enough!)

Magnifique ...

Good question I would also like to know.

Merci à tous.
La charge déterminée ici est le résultat d'un calcul en statique. Celle d'un moteur se multiplie par le nombre de moteurs.
Les calculs en dynamique sont beaucoup plus complexe et nécessitent de connaître parfaitement la structure et la répartition des masses.
La grande majorité d'entre nous se contente de cette approche statique en appliquant une marge de réserve de 10 à 25% à ce calcul. Ensuite l'expérimentation fait le reste...

Thank you all.
The load determined here is the result of a static calculation. That of an engine multiplies by the number of engines.
The calculations in dynamics are much more complex and require to know perfectly the structure and the distribution of the masses.
The vast majority of us are satisfied with this static approach by applying a reserve margin of 10 to 25% to this calculation. Then experimentation does the rest ...

Excellent!