[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. 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 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 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 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 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 The case for reducing motors, side view, appears briefly as follows: Gearbox output shaft position 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 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 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.