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18 Feb 2019, 11:12

Turning Virtual Reality into a Fully Immersive Experience

Radial G Virtual Racer

Colleagues at RS Components, Austella and ebm-papst UK got together to discuss a new project: adding an extra dimension to the Radial-G virtual reality racer, in order to make the game a fully immersive experience. Working together to turn the concept into a working system grew to be a very interesting and exciting challenge.

The Brief

The Radial-G Virtual Reality game puts the gamer inside the cockpit of a hover racer, competing for supremacy against a group of opponents. The game has multiple skill levels from novice to expert, multiple track layouts and the choice of conventional racing mode or adversarial battle mode for a more combative experience. Racers must navigate the track, picking up speed at booster gates, avoiding braking gates and being shot by opposing racers whilst negotiating the twists, turns and jumps along the way.

To augment the experience, the game designers wanted to make the experience more immersive, to get the physical feeling of movement whilst in the game environment. To achieve this, the idea of a fan blowing air over the gamer, varying the velocity as the virtual hover racer accelerates and decelerates in the game was conceived.

The Fan Selection

With the game developed, the question that needed consideration was the type of fan to deliver the effect. The directionality of the air, the airflow pattern, the velocity of the air over the gamer during play, the speed of response from the fan and its noise level were all considerations to be taken into account.

Axial fans by their nature have a relatively straight air path which results in a flow pattern on the exhaust side which is directional and spreads out in a cone shape over distance. This effect also meant that a smaller compact fan could be aimed directly at the gamer to deliver the effect of travelling at speed.

The next consideration was the velocity of the air as it passes over the gamer. Whilst the virtual speed of the hover racer is fast the experience needs to be enjoyable and exhilarating. For most of us who ride bicycles reaching a speed of 25mph is achieved whilst travelling downhill with an assisting wind. At this speed, the wind in our faces adds to the excitement of travelling fast. For this reason, the volume flow from different sizes of axial fan (80mm to 150mm diameter), was calculated to deliver a velocity of up to 25mph.

To achieve the flow rates required from a relatively small device, a DC compact fan was chosen for its high power density. The 24V DC fans chosen for the tests were also equipped with a dedicated speed control signal input and being a low voltage device, the risks associated with electrical safety were reduced.

Once a selection of fans was chosen it then came to the real testing. The fans were bench tested in a workshop environment to test the velocity, air flow pattern, speed of response and noise level. Placed in a simple mounting frame the fans were aimed at a simple frame with cord attached to visualise the air as the gamer would experience it. The fans were powered up, connected to a speed control signal and run at various speeds. This reduced the number of fan possibilities down to 4.

In parallel, the software design company were working on a method to communicate the speed signal out from the game, to the fan. The game is capable of transmitting data out however, the fans require an open collector PWM signal to vary their speed, so an interface to convert data into a variable signal would be required. The chosen solution was an Arduino (available from RS Components) to convert the data from the game into a 0 to 5V analogue output signal. This signal was then fed to an ebm-papst configurable generic controller (CGCXX00000), which was configured with a response profile to convert the 0 to 5V analogue output signal into a 0-100% open collector PWM output to the fan.

The Gaming Trial

The stage was set at the next meeting to try the system for the first time with the fans selected during bench testing. The gaming station was set up with the fans in front of the gamer to obtain subjective feedback of the experience.

After a few trial runs using the fans selected for the test, it became clear that in all respects the 6314/2TDHHP compact fan (055-7723) proved to be the most appropriate fan selection.

Once the fan selection was known, the package in which they would be supplied was discussed. The 6314/2TDHHP is a fan supplied with flying lead connection with a round housing. There is no guarding supplied on the suction or exhaust sides and with the fan having 5 rigid plastic blades rotating at 7200 rpm, a housing was required to eliminate the risk of accidental exposure to an electric shock and the risk of coming in to contact with the rotating blades.

After some discussion, the concept of the fan boxes was drawn up. Two fan boxes, each with two fans, would be used per gaming station. The boxes could be used in a vertical or horizontal position with the airflow aimed at the gamer. The fans would be mounted at two angles (parallel and oblique), to provide an effect that surrounds the gamer. Each fan would be fitted with a switch to isolate the power and control signal, enabling individual fans to switch off without affecting the operation of the other fans being used. Isolating the fans as required would provide flexibility in the amount of air delivered and the pattern it would be delivered in.

The connection at the box for the power and signal of the fans would be designed to accept a panel mount plug fit connector, readily available from RS Components.

Prototyping and Field trial

Based on the initial sketches, the fan box concept was developed into a working model using 3D CAD modelling and transferred in CAM files to a CNC punch and bending machine for processing. Fans, finger guards, isolation switches, power supply and electrical connectors, all available via RS Components, were specified to produce the final fan box assembly.

A sample pair was fabricated and hand assembled to trial the concept and ensure the fan boxes provided the desired effect when the gamer was in play.

After some feedback from the game designers as well as exhibitions, RS Components events and trials at ebm-papst, the fan boxes required some tweaking to improve the fan response to live game action.

Finally, a game inspired merchandising skin was commissioned, printed and applied to complete the project and produce the first draft of the final product.

The Next Steps

Further development is on-going to allow direct communication from the game to the CGCXX00000 fan controller, using its serial programming interface to reduce the complexity and cost of the system. A safety review of the design is also currently on-going whereupon completion it is hoped the product will be ready for commercial use.

Summary

Whilst the project is not a traditional industrial or commercial use of a fan and virtual reality hardware, the result is an exhilarating and exciting gaming experience accessible to all. In addition to the Radial-G virtual racer game, using fans to transform the experience of other virtual reality software, immersing the participant into the virtual world can be achieved simply and effectively through collaboration. DesignSpark is one of those places where collaboration can happen.

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My background is in Mechanical & Production Engineering however working for ebm-papst that has expanded into electro-mechanical, some electronic and acoustic engineering. When it comes to acquiring and passing on knowledge, I try to keep it as simple and as least painful as possible. I am happy to receive feedback and if there are any questions that arise from anything that gets published. If I don't know the answer to your question immediately, I am sure that I know someone that can help.

18 Feb 2019, 11:12