Force Feelin Haptic Integration of IBM Manipulator

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Force Feelin Haptic Integration of IBM
Manipulator
Scott Gunther Adrián Cuadra Matt
Kalkbrenner Krista Hirasuna Colson Griffith
Carol Reiley
Senior Design Conference Interdisciplinary
Session I May 6, 2004
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Outline

• Introduction to Haptics
• Project Goals
• Project Overview
• Subsystems
• Video Demonstration
• Experiments and Analysis

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Introduction to Haptics

• Haptikos - to come into contact with
• Also known as force feedback
• Real world uses include
• Underwater research vessels
• Hazardous material manipulation
• Surgical applications

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Project Goals

• Develop force feedback system and integrate with
  robotic arm
• Robotic arm modifications and rotational input
  device (RID)
• Human Interface Controller (HIC) that conveys
  force to operator
• Gripper that senses force
• Experimentation and testing
• Computer analysis
• Performance characterization
• Users experiences

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System Overview
Arm Gripper Torque
Human Interface Controller (HIC) and Rotational
Input Device (RID)
MOTOR CONTROLLER MICROCONTROLLER
Gripper Force Arm Position
Gripper Force Feedback
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Human Interface Controller (HIC) and Gripper
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Design Process Gripper / HIC

• Researched existing designs
• Brainstormed new solutions for a robotic gripper
• Performed Tradeoff Analyses
• Manufacturability
• Duality
• Linearity

Pictures Courtesy of Immersion Corp. and Stanford
University
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Design Process Gripper / HIC
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Mechanical Components Gripper / HIC

• Machined from Al T6-6061
• Nylon slides decrease friction
• Motor turns pinion, pinion moves palette via
  attached rack

Pinion
Motor
Rack
Rack Guard
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Electrical Components Gripper / HIC

• Encoders detect motor position
• Force Sensing Resistor (FSR)
• Range 0-2.5 Newtons
• Linear assumption
• Correlation Co. .9043
• Wilson Current Mirror

Vout
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Signal Flow Diagram Gripper / HIC
GRIPPER
FSR
Microcontroller
Motor Driver
FSR
Force Control
Position Control
Motor Driver
Encoder
Encoder
Human Interface Controller
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Robotic Arm and Rotational Input Device (RID)
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Mechanical Components Robotic Arm/RID

• Robotic Arm
• IBM 7545 industrial manipulator donated to SCU
• Rotational Input Device
• Machined from polycarbonate
• Rotates on lazy susan bearing
• Potentiometer

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Electrical Components Robotic Arm/RID

• Arm movement
• Rotational movement position control
• Up/Down movement open loop speed control

Arm
Analog Voltage
Current
Micro- Controller
PWM
Motor Controller
HIC
Current
Rotational Potentiometer
PWM
Up/Down Switch
Analog Voltage
Off/On
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• Video

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Experimentation and Analysis
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Finite Element Analysis
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Experimental Data Gripper Force Mode
Delay Time td200ms
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System Block Diagram Robotic Arm
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Experimental Data Robotic Arm
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Experimental Data Robotic Arm

SS-Offset T2 deg
90 Rise Time tr3.2s
Delay Time td200ms
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Usability Survey

• 15 people of various backgrounds tested the
  system
• Filled out a survey consisting of 10 questions
• Results
• 100 preferred force feedback over position
  control
• 100 could distinguish between hard and soft
  objects
• 80 said system was easy to use

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Improvements

• Reduce resistance of opening HIC
• Add a computer interface for the control of the
  system
• Explore the impact of derivative and integral
  gains on force control
• Increase range of sensitivity of force sensors

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Accomplishments

• Developed a haptic system and integrated it with
  a robotic arm
• Replaced existing controller with new system
• Ability to switch between force feedback and
  position control
• Pioneers of haptics at SCU
• System to be used as lab tool in
• SCU robotics
• Continued by future senior
• design teams

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Acknowledgments

• Senior Design advisors- Professors Kitts, Quinn,
  and Hight
• Pascal Stang
• Don Macubbin, Calvin Sellers, Tibor Hites
• Tim Pargett
• Deans Fund and Student Leadership Fund
• Survey Volunteers

Our robot through the eyes of 2nd graders
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Questions

• ???

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Thank You

• Please, come and feel the difference for
  yourself

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Appendix 1 FSR Calibration
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Appendix 2 Gain Plots
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Appendix 3 Further Analysis

• Analysis of screws

F
?MA 0 2.226in (F) 0.224in (-252 lbs)
Fmax 25.36 lbs/screw

of screws Fmax 225.36 50.72 lbs Motors
can apply 117 in-oz of torque at 1.41 A and 24
V. 117 in-oz 7.3125
in-lbs
A
B
Gear Radius .5 in Tmax 7.3125 in-lbs
Fmax Tmax/Gear Radius 14.625 lbs
N (Ideal Fmax)/(Real Fmax) N
(50.72)/(14.625) 3.5
Gear
Material Properties Yield Strength 42
kpsi 4-40 screw tensile stress area 0.006
in2 42 x .06 252 lbs max load 252 lbs
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Appendix 4 Design Process
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Appendix 4 Design Process