Group 10

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Group 10 Helping Hand
Taylor Jones Eric Donley Kurt Graf Matt Carlson
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OUR PROJECT IS

• A Haptic Robotic Arm controlled by a sleeve
  mounted with motion and force sensors on a human
  operator's arm which controls the
  motion-tracking robotic arm's proportional
  motion.
• These robots have a wide range of industrial and
  medical applications such as pick and place
  robots, surgical robots etc. They can be employed
  in places where precision and accuracy are
  required. Robots can also be employed where human
  hand cannot penetrate.
• Theoretically, adding digits (fingers) to the arm
  with extremely fine control could make a skilled
  work duplication station possible.
• That means you make a part at your workstation
  and the Helping Hand duplicates your work on a
  robotic station.

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Motivation for Project

• We are Electrical Engineers and a Computer
  Engineer candidates for Bachelor of Science
  in Engineering diplomas
• Concern for real working world (industrial)
  knowledge and skills led the team to choose for
  senior design project a modern application of an
  industrial standard robotic application - the
  robotic arm.

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PROJECT CONCEPT
Why study the human-operated robot arm? The
future of robotics in manufacturing and assembly
is increasing flexibility both in mechanical
performance and ubiquitous integration with human
workers. The future of robotics is greater
dexterity, easier and quicker programmability,
and safe operation with human co-workers.
Building a tele-operated master-slave robot arm
driven by sensors worn on a human arm is
investigating future possibilities and general
performance considerations of advanced robotics.
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Goals and Objectives of Our Project
1. Proportional motion-tracking of a human
operator's arm motion 2. Fast tracking response
or lt 0.1 seconds 3. Effective grasp-and-place
50 gram object with end-effector 4. Smooth and
safe and stable motion 5. 61DOF with elbow and
wrist roll
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Specifications of Performance

• Less than 0.1 second (human reaction time) delay
  from
• human arm motion to robot arm motion-tracking
  response
• Automatic reset to start position
• 3. Internal range-of-motion limitation
  fail-safes
• 4. Grasp, lift, and place 50 gram payload
• 5. End-effector does not damage payload

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Not an Open Loop SystemExteroceptive (operator)
Feedback
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System Overview
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AL5D Arm

• Length 20 in.
• Gripper width 1.25 in.
• Degrees of freedom 7

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MPU-6000/6050 Six-Axis MEMS
MPU-6000/6050 Six-Axis (Gyro Accelerometer)
MEMS MotionTracking Devices for Smart Phones,
Tablets, and Wearable Sensors
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Completed sensor board with 4x4x1 mm gyro
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TWI Timing

• V(0) 0
• V(inf) Vcc
• Vcc Vc IR
• Vcc Vc RCdVc/dt
• dVc/dt Vc/RC Vcc/RC
• Vc Vcc(1-e(-t/RC))

• High gt 0.7Vcc
• Low lt 0.3Vcc
• tmax 300ns

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TWI Timing

• 0.7Vcc Vcc(1-e(-t/RC))
• 0.7 1 e(-t/RC)
• -t RCln(0.3)
• RC -t/ln(0.3)
• t lt 300ns
• RC lt (30010(-9))/ln(0.3)
• RC lt 2.4910(-7)

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GYRO Equation
The gyro gives data in degrees/second To
determine actual angle of rotation requires
integration with respect to time ?dT dt T
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Mounted Sensors
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Motor Choice
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Microcontrollers
Name I/O pins Memory A/D converter PWM Language Price
Basic ATOM 24 24 14k code 368 RAM 256 EEPROM 11 channels 3 channels BASIC 8.95
PICAXE-20X2 18 4k code 256 RAM 11 channels 0 channels BASIC 3.88
ATxmega128A4U 34 128k code 8k SRAM 2k EEPROM 12 channels 16 channels C or Assembly 3.00
Propeller 40 pin DIP 32   64k RAM/ROM   0 channels 0 channels Created in code Spin 7.99
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Operational Flow Chart
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Software Flow
Main Loop -int main(void)
Motor Control Void init_motors(void) Void
move_to_default(void) Void move_motors(uin8_t7)
IO control Void init_pins(void)
Math Functions void getQuaternion(int16_t,const
uint8_t) void createQuaternion(Quaternion,const
uint8_t) void GetGravity(VectorFloat,Quaternio
n) void GetYawPitchRoll(ypr,Quaternion,VectorFl
oat) void loadBuffer(uint8_t,accel_t_gyro_union
)
Sensor Control Void init_sensors(void) Void
init_twi(void) Void read_sensors(void) Void
translate(accel_t_gyro_union, accel_t_gyro_union,
accel_t_gyro_union)
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Motor Coordination

• Base motor is controlled by the yaw of the bicep
  sensor
• Shoulder motor is controlled by the pitch of the
  bicep sensor
• Elbow rotation is controlled by the roll of the
  forearm sensor
• Elbow motor is controlled by the yaw of the
  forearm sensor
• Wrist rotation is controlled by the roll of the
  hand sensor
• Wrist motor is controlled by the pitch of the
  hand sensor
• Grip motor is controlled by a button located on
  the finger

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Sensor Data Conversion
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TESTING

• A plastic robot arm prototype was built and
  proved very useful for component acquisition. In
  particular, an arduino control board was used to
  initially test the gyro sensor boards and to test
  the servos after mounting them on the metal robot
  arm.
• 3 systems components required testing
• 6-axis gyroscope-accelerometer sensors
• Digital and analog servo motors
• Microcontroller board

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Testing Results

• 7 servos plus two spares were tested out of the
  box OK
• 7 servos plus two spares tested on robot arm 5
  OK
• Base and shoulder servos arent strong enough
• Base only rotates plus or minus 5 degrees
• Shoulder only rotates 30 degrees
• 4 6-axis MPU-6050 gyro-accelerometers tested
  individually OK
• 6-axis MPU-6050 gyro-accelerometers not tested
  in system
• 1 MCU built and tested unconnected to
  sensor-robot system OK
• MCU not tested in sensor-robot system

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Power Supply

• Two different supplies are needed
• Microcontroller and sensors
• Rated at 3.3v
• Servos
• Rated at 6v

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Power Supply

• Initial plan
• Battery Pack
• 6v
• Limitations
• Current

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New Plan

• Power plug through the wall
• Advantages
• Limitless power supply
• Configurable for high current
• Disadvantages
• Bulky
• Increase costs

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• Use of transformer to step down the voltage from
  the wall to 6v
• Then rectify the voltage to DC
• Use of linear regulator to further drop the
  voltage to 3.3v

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Combine 2 power supplies in one using a shared dc
power bus and dc-to-dc regulator
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Single PC 350 Watt P/S configured as a Shared DC
Power Bus at 5 Volts for servos and dc-to-dc
regulated to 3.3 Volts for sensors and
micro-controller unit
5 Volts
3.3 Volts
PC 350 W P/S driving 18 amps at 5 volts
Wrist/ Forearm rotation Servo
Elbow rotation Servo
Shoulder elevation Servo
Elbow elevation Servo
Base Servo
Wrist elevation Servo
MCU
120V AC in
Gripper Servo
Gyro Forearm
Gyro Hand
Gyro Bicept
LD1117AV33
PC Power Supply
Connection board
5V to 3.3V Voltage Regulator
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Work Remaining to Complete Demo
1. Programming effectiveness between sensors,
mcu, and servos tested and proven 2. Power
supplies built, tested, implemented 3.
Mechanical and electrical system performance
documented
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Budget
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