Robotic Arm Replicating Human Hand Movement

Reading Time: 6 minutes

 Topics

  1. Anatomy of Human Hand
  2. Present Data Glove Technologies
  3. Glove Accessories
  4. Applications
  5. My Project

 

1      Anatomy of Human Hand

anatomy_1

anatomy_2

Human hand has 23 degrees of freedom:

 4 in each finger,

3 for extension and flexion and

one for abduction and adduction;

thumb is more complicated and has 4 DOF;

leaving 3 DOF for the rotation of the wrist

2      Present Data Glove Technologies

 

 

  • Pinch Glove

    Pinch-Glove
    Image Courtesy: http://www.mechdyne.com/

The first prototype, originally called the Chord Glove, was developed by Mapes at the University of Central Florida.Commercialized by Fakespace Laboratories (Mountain View, CA), it uses electrical contacts at the fingertips, on the back of fingers, or in the palm. When two or more electrical contacts meet, a conductive path is completed and a posture can be made. The PinchGlove interface detects whether a posture has been made and keeps a record of the posture duration. Postures can be programmed, and no additional posture recognition techniques are required. This makes the PinchGlove excellent for posture recognition with over 1000 postures theoretically possible.It uses polling algo. Asalient feature of this glove is that it does not require calibration. [1]

  • Didgi Glove  

    didgiglove
    Image Courtesy [1]

Commercialized by Didjiglove Pty, Ltd., the Didjiglove uses ten capacitive bend sensors to record finger flexion (fingers MCP and PIP, and thumb TCMP and MP). The sensors consist of two layers of conductive polymer separated by a dieletric. Each layer is comb-shaped; a change in the amount of sensor bending results in a change in the overlapping electrode surface, and ultimately in a change in capacitance. The Didjiglove requires calibration: to calibrate the glove, the user makes hand shapes and records these by pressing. It has small glove latency  (10ms)  It is designed for computer animation, and specifically to function as an advanced programming interface for toolkits such as 3-D Studio Max and Maya for which software drivers are provided. [1]

  • Cyber Glove

    Image Courtesy: http://www.vrealities.com/
    Image Courtesy: http://www.vrealities.com/
  • Cyber Force Image Courtesy: http://www.prweb.com/
    Cyber Force Image Courtesy: http://www.prweb.com/

 CyberGlove, created by Virtual Technologies, Inc. in 1990. Virtual Technologies was acquired by Immersion Corporation in September 2000. In 2009, the CyberGlove line of products was divested by Immersion Corporation and a new company, CyberGlove Systems LLC, took over development, manufacturing and sales of the CyberGlove.[2]

Image Courtesy: http://home.12move.nl/
Image Courtesy: http://home.12move.nl/

It comes equipped with 18 or 22 piezo-resistive sensors. The 18-sensor model features two bend sensors on each finger (MCP and PIP joints), and four abduction/adduction sensors ,plus sensors measuring thumb crossover, palm arch, wrist flexion, and wrist abduction/adduction. The 22-sensor model features four additional sensors for measuring DIP joints flexion. Calibration is needed to make glove measurements insensitive to differences in users’ hands, finger length, and thickness and convert sensor voltages to joint angles. It is performed with the Virtual Hand calibration software by having the user flex their hand a few times and editing the gain and offset parameter value for each sensor to best match the motion of the virtual hand to the physical hand. [1]

In addition to the CyberGlove, Immersion Corp also developed three other data glove products: the CyberTouch, which vibrates each individual finger of the glove when a finger touches an object in virtual reality; the CyberGrasp which actually simulates squeezing and touching of solid as well as spongy objects; and the CyberForce device which does all of the above and also measures the precise motion of the user’s entire arm.

  • Human Glove

Patented in 1997, it is commercialized by Humanware Srl (Pisa, Italy). It is equipped with 20 Halleffect sensors that measure flexion/extension of the four fingers MCP, PIP, and DIP joints and flexion/extension of the thumb TMCP, metacarpal phalangeal (MP), and interphalangeal (IP) joints, aswell as fingers and thumb abduction/adduction; two additional sensors measure wrist flexion and abduction/adduction.Glove calibration is similar to that of the CyberGlove and is performed through a software package called Graphical Virtual Hand, which displays an animated hand that mirrors movements of the user’s hand.

The Humanglove is a sensorized elastic fabric glove designed and commercialized by Humanware. The Humanglove is equipped with 20 Hall effect sensors. Each sensor measures data related to a DOF of the hand. The nominal sensor characteristics are resolution, 0.4° over a range up to 90°; linearity, about 1 percent full-scale output; and accuracy, about 1°. However, no information about the sensors is available concerning their performance when they are mounted on the elastic fabric glove.[1]

  • 5DT Data Glove 

Uses optical-fiber flexor sensors 1 sensor per finger to measure overall flexion of the

Image Courtesy: http://www.metamotion.com/
Image Courtesy: http://www.metamotion.com/

four fingers (average of MCP and PIP joint flexion) and thumb (average of MP and IP joint flexion)& 1 tilt sensor to measure tilt of wrist. Gesture library uses binary open/close configurations for the fingers, excluding the thumb, so that 2^4 = 16 possible gestures can be generated.   (V) [1]

3      Glove Accessories

A complete description of hand movement requires knowledge of

1. Hand configuration (amount of joint bending or joint relative positions)  – Sensor Glove

2. Hand position in space (location and orientation of the hand, for a total of 6 DoFs—3 for translations and 3 for rotations) – 3 D Trackers

Key performance parameters  of sensor– accuracy in dergrees , jitter, drift and Latency

Sensor are broadly classified into

  • Magnetic
  • Ultrasonic
  • Optical
  • Inertial
Tracker

Principal

Advantage

Disadvantage

Magnetic-Hall-effect eg RFID
Magnetic field producedby a stationary transmitter to determine the positionof moving receiver elementlowcost, reasonable accuracy, and no requirement of directline of sight transmitter–receiversensitivity to magnetic fields and ferromagnetic materials.
Ultrasonic
Ultrasonic signalproduced by a stationary transmitter to determine the positionof a moving receiverNo metallic interferenceSuffer from echoes from hard surfacesRequire direct line of sight Update rate is approximately 50 datasets/s, less than half that of magnetic trackers
Optical
Uses optical sensing to determine the real-time position/orientation of an objectInsensitive to metallic interferenceline of sightSensitivity to reflection of light from surfaces in theenvironment.
InertialEg Accelerometer
measures the rate of change of an object’s orientation or therate of change of an object’s translation velocityUnlimited rangeNo line-of-sight constraintsLow sensor noiseSensitive to drift and bias of thesensors

 

 

4      Applications

  • 3D Modelling
  • Virtual Training
  • Control a robot
  • Tech a robot in natural way
  • Video Games
  • Communication System for Deaf
  • Motor rehabilitation, human motion analysis
  • Wearable Computers
  • (V)

5      My Project

Till now I completed the survey of kinds of Data Glove and the kind of technology they use. I have also created my virtual reality model. Future steps I will undertake

  1. Decide Sensor’s which are most appropriate for my application
  2. Intergate sensors with hardware to process the data- NI Hardware  (V)
  3. Virtual Hand Designing in Autodesk Inventor(Completed)
  4. Integrating VR Hand  to sensory data – NI Labview

Pics of hand I designed in Autodesk Inventor

 

 myproject_5 myproject_2 myproject_1
 myproject_7 myproject_4 myproject_6
 myproject_7 myproject_9 myproject_3

So keep following this post for viewing the future work in this project!!!!!

#References

[1] Dipietro, L.; Sabatini, A.M.; Dario, P., “A Survey of Glove-Based Systems and Their Applications,” Systems, Man, and Cybernetics, Part C: Applications and Reviews, IEEE Transactions on , vol.38, no.4, pp.461,482, July 2008

[2] http://en.wikipedia.org/wiki/Wired_glove 

Modern Marvel-Touch Screen

Reading Time: 9 minutes

Topics being covered :-

 

1.Introduction

2.Types of touchscreens

3.Resistive touch

4.Capacitive touch

5.Acoustic touch

6.Infrared technology

7.Comparison between various touchscreens

 

Introduction

Do you know what a touch screens is?

It is a human machine interface (HMI). HMI, as its name indicates, is an interface or device that allows communication between machine and its user.

A touch screen is also this type of HMI that uses images for communications between a user and electronic device. Unlike mouse and keyboard, touch screen allows a user to interact with electronic device by directly touching images displayed on the screen.

Touch screen itself is just a transparent switch that detects touched locations. How the device reacts to your touches is controlled by software. Various input devices can be made with combination use of touch screen, display and software.

 

Advantages

1. Switch and buttons are not physically required. Device makers can make and modify various input interfaces creatively by software.

2.With multi-touch function, various operations/inputs (eg: zoom-in/zoom-out, rotation) are possible.

3.Because a user operates an electronic device by directly touching the images on the display he is seeing, the operation will be intuitive, thus anyone can operate it from first use.

4.The whole unit is space-saving because display and input space are integrated. There is a lot of flexibility in design.

5.Unlike keyboard or physical switch, there will be no dirt, dust, and moisture getting into the spaces between buttons. Thus, it is easy for maintenance.

 

Disadvantages

1.Since a display is directly touched, the display may get dirty, then become less-visible. A direct touch may also cause scratches on the screen that may cause malfunction in some cases.

2.Unlike push-button and mouse, users will not feel “click” when a user input a touch screen, thus operation may become clumsy sometimes. However, there are certain touch screens that provide “click feeling” when touched.

 

Resistive touch

 

4 Wire Touchscreen

They are all constructed similarly in layers-a back layer such as glass with a uniform resistive coating plus a polyester coversheet,

with the layers separated by tiny insulating dots. When the screen is touched, it pushes the conductive coating on the coversheet against the coating on the glass, making electrical contact. (fig 2)

Analog 4-wire resistive is the most basic sensing method of resistive technology.

Top and bottom transparent conductive sheets that have uniform resistance value, are facing each other with a gap.

When the top sheet is touched, the touched point of the top sheet yields, and contact the bottom sheet.

The contacted point is conducted, and its location is sensed.

fig1

fig1

fig2

fig2

 

 

The sensing process (refer fig 1 for understanding)

 

1. Voltage is imposed between the electrode X1 and X2 on the top sheet. Then, there will be formed on the top sheet an equipotential distribution that is parallel to the X1 and X2.

2.Assuming that the electrode X1 is 0V (Ground), then impose 5V to the electrode X2. If the central point between the right and left electrodes is touched, 2.5V would be measured by the bottom sheet. If a    point 1/5 away from X1 (4/5 away from X2) is touched, 1V would be measured by the bottom sheet. The X coordinate point is detected in this way.

3. After detecting the coordinate point in X direction, Voltage is imposed between the electrode Y1 and Y2 on the bottom sheet. The point between Y1 and Y2 (Y coordinate) would be measured by the top sheet, just in the same manner as X coordinate in the step 1-2.

4.As the set of step 1 ? 3 is repeated, the X and Y coordinate points of touched locations keeps being detected.

 

 

5-Wire TouchScreen

In analog 4-wire resistive technology, one sheet has equipotential distribution in X direction, and the other sheet has equipotential distribution in Y direction.

The two sheets measure each others’ voltages. In analog 5-wire resistive technology on the other hand, one sheet (bottom sheet) has equipotential distribution in both X and Y directions. Voltage of the bottom sheet is measured by the top sheet.

 

The sensing process (Refer fig3 for understanding)

 

1. 5V is imposed on the electrodes A and C. The other side (electrode B and D) will be 0V (Ground). In this way, there will be formed an equipotential distribution parallel to AC and BD.

2.   Voltage of a touched point will be measured by the top sheet. If the central point between AC and BD electrodes is touched, 2.5V would be measured by the top sheet. If a point 1/5 away from AC (4/5 away from BD) is touched, 1V would be measured by the top sheet. Touched coordinate point in X direction will be measured in this way.

3.    After detecting the coordinate point in X direction, 5V is imposed on the electrodes A/B. Then, C/D will be 0V (Ground). The point between AB and CD (Y direction) would be measured by the top sheet, in the same manner as X direction.

4.  As the set of step 1 ? 3 is repeated, the touched points in X and Y direction keeps being detected.

fig 3

fig3

An analog 5-wire resistive sensor was regarded as more durable than analog 4-wire resistive sensor.Since,there is no equipotential

distribution formed on the top sheet in analog 5-wire resistive.

So, the top sheet did not need to be good at resistance uniformity and environmental durability in this sensing method.

 

8 Wire touchscreen

 

The structure and sensing method of 8-wire resistive technology is same as 4-wire resistive technology.

Two transparent conductive sheets are facing. One sheet has electrodes on right and left sides, and the other sheet has electrodes on top and bottom sides.

Voltage is imposed on the sheet with electrodes on right and left sides, then a touched point in X direction is detected as the voltage is measured by the other sheet.

Then, voltage is imposed on the sheet with electrodes on top and bottom sides, then a touched point in Y direction is detected as the voltage is measured by the other sheet.

 

fig 4

fig4

You would be thinking it same as 4 wire touchscreen??

Yes,you are right but there are additional wirings connected to each electrode in analog 8-wire resistive technology. Each electrode is added with one more wiring. These added wirings work as supplemental electrodes and measure voltage on each electrodes, then feedback the information to the controller.

Analog 4-wire resistive technology required calibration not only at the beginning but regularly because touch detecting points are gradually going off the alignment due to change of resistance value on wiring and/or connector parts with the passage of time. In analog 8-wire resistive technology, supplemental electrodes measure the voltage on each electrode automatically, and feedback the measured values to the controller. The voltage detected at touching is transformed into locational information in the relative ratio with the feedback voltage. In this way, the effects of voltage change at electrodes can be cancelled, thus recalibration would not be required.

 

Capacitive touch

 

There are two types in capacitive technology that are surface capacitive and projected capacitive.

Surface capacitive is employed for applications such as ATM and factory automation, but demand is limited.

As projected capacitive was developed and started to be employed for smartphone, the number of capacitive touch screen has been increasing dramatically.

Surface Touchscreen

Transparent conductive coating is on the base glass sheet, and glass protective coating is placed over it. Electrodes are placed on the four corners.

fig 5

fig5

Sensing Method

The same phase voltage is imposed to the electrodes on the four corners, then a uniform electric field will be forming over the panel. When a finger touches on the panel, electrical current will flow from the four corners through the finger. Ratio of the electrical current flowing from the four corners will be measured to detect the touched point. The measured current value will be inversely proportional to the distance between the touched point and the four corners.

fig 6.

fig6

Projected Capacitive

There are various structures in projected capacitive technology. “One sheet piled-up structure” has X and Y electrodes piled on one sheet. “One sheet two-sided structure” has X and Y electrodes on its surface and backside of one sheet respectively. “Two-sheets-laminated structure” consists of two sheets facing each other with electrodes in between.

fig 7

fi7

In the two-sheets-laminated structure of projected capacitive, X electrodes are forming on one glass, and Y electrodes are forming on another glass. The two glass sheets are laminated in the way that two electrode sides are facing. The X and Y electrodes are intersecting in matrix.

Sensing Method

There are two types of sensing methods in projected capacitive technology. They are GRID type and wire sensing type. GRID type will be introduced here.

 

Human body is conductive since it contains a lot of water. When a finger comes close to the patterning of X and Y electrodes, a capacitance coupling will occur between the finger and the electrodes. The capacitance coupling makes the electrostatic capacitance between the X and Y electrodes change. The touch sensor detects touched points as it checks where on the electrode lines the electrostatic capacitance changed.

fig 8

fig8

Projected capacitive technology make use of conductivity of human body. Then, you can imagine that projected capacitive can detect only fingers just like surface capacitive.

Projected capacitive can detect gloved finger as well.

fig 9

fig9

 

Acoustic touch

 

Surface acoustic wave technology makes use of ultrasonic waves for detection. It is often abbreviated to SAW.

Let’s look at the structure of the touch screen first.

fig10

fig10

Take a look at the fig10.

Surface acoustic wave touch screen consists of one glass sheet with transmitting transducers, receiving transducers, and reflectors. Transmitting transducers generate ultrasonic waves that travel over the panel surface. The ultrasonic waves are reflected by the reflectors and received by the receiving transducers.

The ultrasonic waves traveling over the panel surface are surface acoustic waves.

Sensing Method

1.If contacted by a soft material, SAW will get absorbed by it. Surface acoustic wave technology makes use of this nature of SAW.SAWs are sent out from the transmitting transducers, and traveling along the edge of panel. The reflectors located on the edge of the panel change directions of the SAWs at the angle of 90 degrees, thus the SAWs travel over the panel. Once the SAWs reached the other side of the panel, their directions get changed again by the reflectors located on the other side, and travel toward the receiving transducers. Once the SAWs are received by the receiving transducers, they will be converted into electric signals.

2.If it is touched by a finger, the SAWs will be absorbed by it and do not reach to the receiving transducer. Then, the sensor detects where the SAWs were absorbed?

3.There are routes on which the SAWs travel from the transmitting transducers to the receiving transducers. Each route has its own distance. If one of the routes is touched by a finger, the pulse will be absorbed, and the SAW on the route will not be received by the receiving transducers. Thus, the sensor will recognize which route was touched, and locate the touched point.

 

 

History & Latest Trends In Microcontroller & Microprocessor

Reading Time: 5 minutes

      

       Topics :-

  • –   Physical View of MPU & MCU
  • –   Moore’s Law
  • –   Key Features Of MPU & MCU
  • –    Bridge between College and Real Life Scenario-Work Of Intel Engineer
  • –   Latest in MPU & MCU
  • –   Leading Companies In MPU

 

Physical View of MPU & MCU:

Historical Background

Fairchild

  • –   Fairchild Semiconductors founded in 1957, invented the first IC in 1959.
  • –   In 1968, Robert Noyce, Gordan Moore, Andrew Grove resigned from Fairchild Semiconductors.
  • –   Found their own company Intel (Integrated Electronics).
  • –   Intel grows from 3 man start-up in 1968 to industrial giant by 1981.
  • –   It had 82,500 employees (2010) and $53.34 Billion revenue(2012).

Timeline:

  • –   1947-Invention Of Transistor
  • –   1959-Invention Of Integrated Circuit
  • –   1965-Birth Of Moore’s Law
  • –   1971-Development of First Microprocessor-4004
  • –   1971-Development of First Microcontroller-TMS1000
  • –   2011 May 2, , Intel announced its first 22 nm microprocessor, codenamed Ivy Bridge, using a technology called 3-D Tri-Gate

 

Gorden Moore’s Law

”The number of transistors on integrated circuits will double approximately every 24 months.”

 moores law

 So what changes do they do actually?

Bring in Advanced Micro-architecture technology which puts in more and more no. of transistors on a unit sized chip

 

Key Features Of MPU & MCU:

  • Smaller Size
  • Lower Cost
  • Higher Reliability
  • Lower Power Consumption-CMOS
  • Higher Versatility
  • More Powerful

 

Bridge between College and Real Life Scenario-Work Of Intel Engineer

What do these Engineers do?[1]

–   Process Engineers-develop the most efficient methods for semiconductor manufacturing using state-of-the-art equipment and materials

–   Yield Engineers– work closely with process engineers to improve product yield and to troubleshoot process flow from root causes to equipment tuning

–   Equipment Engineers–  own and lead the stability, improvement, maintenance and performance functions of extremely advanced tools

–   Design Automation and Computer Aided Design (CAD) Engineers– design, develop, maintain, and provide user support of CAD tools, assist with schematic entry and analysis in the integrated circuit design process, and create and implement computer-controlled automatic test systems. In all of these tasks, their core objectives are simple—to improve quality and reduce costs

–   Hardware and Software
Product Development- ensuring the testability and manufacturability of integrated circuits, optimizing component production, and evaluating, developing and debugging complex test methods. Working with our process technology development and product teams, these individuals help deliver the best process and design effective reliability models based on ROI, process limitations, Q&R requirements and product usage models

–   Component Design and Validation–  responsible for chip layout, circuit design, circuit checking, device evaluation, and validation. Starting with product requirements and logic diagrams, they plan design projects and help address the unique needs of our customers

–   Research and Development– Explore how customers interact with technology, what they love about it, and how to make off-the-wall ideas usable reality. Whether you’re applying new materials, emerging technologies or customer insights, your innovations will be what transforms the computing capabilities of tomorrow.

 

Latest in MPU & MCU:

What the hell is the difference between these i3 i5 and i7 Processors???

I3I5I7
–   Cores-2(dual)–   3-4 MB Cache–   2.93 to 3.06 GHz Clock Speed –   Cores2(dual)/4(Quard)Threads-2/4–   4/(6-8) MB Cache–   3.2 to 3.6/2.4 to 2.6 GHz Clock Speed– Cores-4(quard)8 MB Cache3.06 to 3.2 GHz Clock Speed  
–   Threads-4 Threads 2/4Threads-8
–   Hyperthreading-Yes–   Hyperthreading-Yes/NoHyperthreading-Yes
–   Turbo Boost-No–   Turbo Boost-Yes/YesTurbo Boost-Yes
–   32 nm technology–   32/45 nm technology32-45 nm technology

 

 

Meaning Of Pratik has 64-Bit Laptop???

  • –   It means the Microprocessor has 64 data bus lines.
  • –   So if you have 32 bit Microprocessor, then it means that there are 32 data lines .

Meaning of 256 MB Memory

–   256 =2^8

–   So there are in total 8 address lines

 

Leading Companies In MPU:

 intel

INTEL

 

 

  • –   Integrated Electronics founded in 1968
  • –   Paul Otellini –CEO
  • –   Headquarter-Santa Clara ,California
  • –   Intel has also begun research in electrical transmission and generation
  • –   It has 23,000 employers
  • –    Intel has recently introduced a 3-D transistor that improves performance and energy efficiency.
  • –   Intel has begun mass producing this 3-D transistor, named the Tri-Gate transistor, with their 22 nm process, which is currently used in their 3rd generation core processors initially released on April 29, 2012

Others:

 

 

 History & Latest Trends In Microcontroller & Microprocessor microcontroller vs microprocessorHistory & Latest Trends In Microcontroller & Microprocessor microcontroller vs microprocessorHistory & Latest Trends In Microcontroller & Microprocessor microcontroller vs microprocessor
History & Latest Trends In Microcontroller & Microprocessor microcontroller vs microprocessor History & Latest Trends In Microcontroller & Microprocessor microcontroller vs microprocessor History & Latest Trends In Microcontroller & Microprocessor microcontroller vs microprocessor

 

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