virtual open globe

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Virtual Open Globe

Virtual and Augmented Reality

By:Jaime Andres Rincon Arango


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RVA Realidad Virtual y Aumentada, Curso 2012-2013

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INDEX

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INTRODUCTION ................................................................................................................... 31.1. General Purpose ....................................................................................................... 3

2. BACKGROUND .............................................................................................................. 3

3. MATERIALS .................................................................................................................. 4

3.1. Arduino Nano ....................................................................................................... 5

3.2. IMU-6DOF ............................................................................................................ 5

3.3. Bluetooth Module ................................................................................................. 8

3.4. Flex-Sensor ........................................................................................................... 9

4. OPEN DYNAMIC ENGINE (ODE) ..................................................................................... 9

5. DISCUSIN ................................................................................................................. 12

6. BIBLIOGRAFA ................................................................... Error! Marcador no definido.


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INTRODUCTION

The computer-aided modeling in virtual reality is an important tool that allows immersion

in the environment that is being built, and get the designer can observe from all possible

points of view, which is designing and helps the product improvement as a car, a

mechanical attraction, a building etc..

It is not only important to the visual part of the environment, but also to interact with it, so

it is necessary to use devices that allow the capture of the user's movements. Among these

devices are cameras, inertial sensors and mixed, among others.

This work focused attention on the use of inertial sensors such as accelerometers and

gyroscopes. An IMU or inertial capture unit, which comprises an accelerometer to capture

the acceleration in the three axes (X, Y, Z) and a gyroscope which similarly allows me to

calculate the rate of rotation of the three axes, this coupled with a development board

Arduino Nano, a resistive sensor flexible to capture flexion and finger extension and aBluetooth module for data he sent to the computer.

1.1. General PurposeDesign and build a low cost glove, open hardware and open software, which allows

interaction with virtual environments.

2. BACKGROUNDCurrently, they are developing systems that allow open electronic design projects quickly.One of these development systems is Arduino, its versatility allows the development of

projects such as robots, gaming, home automation and control gloves arms or other

applications such as those shown below:

Fig 1. Glove ultrasonic blind.

http://es.engadget.com/2011/08/22/tacit-un-guante-ultrasonico-para-invidentes/


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Fig 2. Power Glove.http://es.engadget.com/2009/04/04/power-glove-vitaminado-con-arduino-bluetooth-y-

acelerometro-por/

Examples of these gloves are constructed with open platforms, although the market also

are virtual reality gloves, such as those shown below:

Fig 3. CyberGlove Systems CyberGlove III.

http://www.bienetec.es/bienetec/jsp/web/catalogo/productos/cybergloveiii/index.jsp

3. MATERIALSFor construction of this glove uses the following components:

1. Arduino Nano2. IMU-6DOF3. Bluetooth4. Flex-Sensor
http://www.bienetec.es/bienetec/jsp/web/catalogo/productos/cybergloveiii/index.jsphttp://www.bienetec.es/bienetec/jsp/web/catalogo/productos/cybergloveiii/index.jsphttp://www.bienetec.es/bienetec/jsp/web/catalogo/productos/cybergloveiii/index.jsp


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Fig 4. Circuito esquemtico

3.1. Arduino NanoAs control unit and capture the signal from the sensors, you have the Arduino Nano, he

takes care of processing the signals.

Fig 5. Arduino Nano. http://arduino.cc/es/Main/ArduinoBoardNano

3.2. IMU-6DOFThis sensor is composed of a 3-axis gyroscope, 3-axis accelerometer, which are captured

with the hand movements. The accelerometer is responsible for obtaining the acceleration

of the hand, which signal can estimate the angle at which it is located.


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The delivery sensor to microcontroller analog values and that are necessary to process

analog to digital conversion (ADC). When using a 10-bit ADC, the maximum conversion

value will be 1023 and this voltage is calculated. See Equations 1, 2 and 3. This voltage

calculation is repeated for the three inputs from the accelerometer and gyroscope.

Once the voltage Dv is calculated on all axes, using the voltage plus the manufacturer

delivery in sensor characteristic sheet (VzeroG = 1.65 V). This delta calculation shown inEquations 4, 5 and 6.

Having already v y knowing the sensitivity value (0.4785 V) also delivered by the

manufacturer, you can get the inertial components of the force of gravity to the X, Y, Z,

using equations 7, 8 and 9. In Figure 6 components found inertial force vector.


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Fig 6. Componentes Inerciales del Vector de Fuerza [starlino,3]

With these components can now calculate the vector R, and for this equation 10 is used.

Having already calculated the R vector angle estimating now Azr, Ayr, Axr, using equations

11, 12 and 13.

In gyroscope is what we want to obtain the rate of change in deg / sec, so it is necessary to

know the sensitivity of the gyroscope, which is 0.002Voltios having this data is calculated

turning rat as shown in equation 14.

Varef is constant reference analog voltage in this case is 3.3 volts. In Figure 7 shows the

components for the gyroscope.


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Fig7. Componentes del Gyroscopio [starlino, 3 ]

And estimated bearing angles of both the accelerometer and the gyroscope are estimated

standard end angles.

3.3. Bluetooth ModuleThe Bluetooth module is in charge of sending data to the computer, using the RS-232

protocol, the Arduino sends a data string which is encapsulated estimated angle values,

the values of the acceleration voltage and the value in flex sensor voltage. Figure 8 showsthe Bluetooth module used.

Fig 7. Modulo Bluetooth


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3.4. Flex-SensorThis is a resistive sensor, which varies its value depending on the deflection have unit. This

sensor is located in the fingers. Figure 8 shows the physical form of the sensor.

Fig 8. Flex-Sensor

4. OPEN DYNAMIC ENGINE (ODE)

Open Dynamic Engines (ODE) is a physics simulation library written in C + +, with whichyou can perform simulations of rigid bodies, body dynamics and collision detection.

The virtual environment was created entirely with ODE. Arm was used, which was built an

API that allows access to data capture serial port, a section of calculations which were

programmed functions for signal filtering, smooth type filter and Kalman filtering, these

filter can eliminate involuntary movements or small movements that would make the

virtual model moved the wrong way.

Smooth filter allows smoothing the input signal, in order to avoid jerking. Smooth filter for

Equation 15 was used.

(15)

The graph of the signals are shown in Graph 1 for movement in X and in Figure 2 for the

movement in Y.


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Grafica 1. X axis movement

Grafica 2 Y-axis movement

The data shown in these graphs were obtained when the hand was in neutral. In Figures 3 shows

the data obtained by making flexion and extension of the wrist for the X axis (MMAX).

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-14

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-10

-8

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01

94

187

280

373

466

559

652

745

838

931

1024

1117

1210

1303

1396

MMAX

Smooth - MMAX

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-16

-14

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-8

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01

94

187

280

373

466

559

652

745

838

931

1024

1117

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1303

1396

MMAY

Smooth - MMAY


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Grafica 3. Flexion-extension movement

Chart 4 is the data obtained by making the movement of pronation and supination of the forearm to

the Y axis (MMAY).

Grafica 4. Pronation-supination movement.

In this graph we see that the filter does its job Smooth, smoothing the signal and avoid

sudden movements.

-2,0000E+01

-1,5000E+01

-1,0000E+01

-5,0000E+00

0,0000E+00

5,0000E+00

1,0000E+01

1

309

617

925

1233

1541

1849

2157

2465

2773

3081

3389

3697

4005

MMAX

Smooth - MMAX

-2,0000E+01

-1,5000E+01

-1,0000E+01

-5,0000E+00

0,0000E+00

5,0000E+00

1,0000E+01

1,5000E+01

1

309

617

925

1233

1541

1849

2157

2465

2773

3081

3389

3697

4005

MMAY

Smooth - MMAY


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5. DISCUSSIONFor improvement of this prototype, it is advisable to use a IMU but the output data are not

similar, because in the micro controller in this case Arduino, the analog inputs are limited.

In this glove sensors occupy all Arduino entries in the market but can be found IMU's thesame type but with I2C and PCI communication thus could be left free analog inputs for

connecting other sensors flex .

As for the virtual environment can be improved using 3D Delta or other software for the

design of virtual worlds, this would increase the applicability of the glove. One might even

think of the connection of the glove to mobile devices.

Something not speak was the haptic feedback, get some information coming from the

virtual world that we feel with the glove, the glove has installed an engine in the event of

receiving a data that comes from the virtual environment, to vibrate , although in this case

the virtual environment does not provide this information to produce this sensation.

6.REFERENCES

1. starlino, A Guide To using IMU (Accelerometer and Gyroscope Devices) in EmbeddedApplications. December 29, 2009

2. Simon Haykin, ADAPTATIVE FILTER THEORY. 1986 by Prentice-Hall3. Paul D. Groves, Principles of GNSS, Inertial, and Multi-Sensor Integrated Navigation

Systems (GNSS Technology and Applications).

4. http://www.ode.org/5. http://dreamcaller.tistory.com/entry/ODE-322-Robot-arm-with-hand-attached-to-

the-bodypanel6. http://www.chem.uoa.gr/applets/appletsmooth/appl_smooth2.html
http://www.ode.org/http://www.ode.org/http://dreamcaller.tistory.com/entry/ODE-322-Robot-arm-with-hand-attached-to-the-bodypanelhttp://dreamcaller.tistory.com/entry/ODE-322-Robot-arm-with-hand-attached-to-the-bodypanelhttp://dreamcaller.tistory.com/entry/ODE-322-Robot-arm-with-hand-attached-to-the-bodypanelhttp://dreamcaller.tistory.com/entry/ODE-322-Robot-arm-with-hand-attached-to-the-bodypanelhttp://dreamcaller.tistory.com/entry/ODE-322-Robot-arm-with-hand-attached-to-the-bodypanelhttp://www.chem.uoa.gr/applets/appletsmooth/appl_smooth2.htmlhttp://www.chem.uoa.gr/applets/appletsmooth/appl_smooth2.htmlhttp://www.chem.uoa.gr/applets/appletsmooth/appl_smooth2.htmlhttp://dreamcaller.tistory.com/entry/ODE-322-Robot-arm-with-hand-attached-to-the-bodypanelhttp://dreamcaller.tistory.com/entry/ODE-322-Robot-arm-with-hand-attached-to-the-bodypanelhttp://www.ode.org/

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