Group 10 – Helping Hand
Taylor Jones
Eric Donley
Kurt Graf
Matt Carlson
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.
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.
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 coworkers. 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.
Goals and Objectives of Our Project
1. Proportional motion-tracking of a human operator's arm motion
2. Fast tracking response = or < 0.1 seconds
3. Effective grasp-and-place 50 gram object with end-effector
4. Smooth and safe and stable motion
5. 6+1DOF with elbow and wrist roll
Specifications of Performance
1. Less than 0.1 second (human reaction time) delay from
human arm motion to robot arm motion-tracking response
1. 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
Not an Open Loop System
Exteroceptive (operator) Feedback
System Overview
AL5D Arm
• Length : 20 in.
• Gripper width : 1.25 in.
• Degree’s of freedom : 7
MPU-6000/6050 Six-Axis MEMS
MPU-6000/6050 Six-Axis (Gyro + Accelerometer)
MEMS MotionTracking™ Devices
for Smart Phones, Tablets, and Wearable Sensors
Completed sensor board with 4x4x1 mm gyro
TWI Timing
• V(0) = 0
• V(inf) = Vcc
• Vcc = Vc + I*R
• Vcc = Vc + R*C*dVc/dt
• High >= 0.7*Vcc
• Low <= 0.3*Vcc
• tmax = 300ns
• dVc/dt + Vc/RC = Vcc/RC
• Vc = Vcc(1-e^(-t/RC))
TWI Timing
• 0.7*Vcc = Vcc*(1-e^(-t/RC))
• 0.7 = 1 – e^(-t/RC)
• -t = RC*ln(0.3)
• RC = -t/ln(0.3)
• t <= 300ns
• RC <= (300*10^(-9))/ln(0.3)
• RC <= 2.49*10^(-7)
GYRO Equation
The gyro gives data in
degrees/second
To determine actual angle of
rotation requires integration with
respect to time
∫dΘ dt = Θ
Mounted Sensors
Motor Choice
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
Operational Flow Chart
Software Flow
Motor Control
Void init_motors(void)
Main Loop
-int main(void)
IO control
Void init_pins(void)
Void move_to_default(void)
Void move_motors(uin8_t[7])
Sensor Control
Void init_sensors(void)
Math Functions
void getQuaternion(int16_t*,const uint8_t*)
void createQuaternion(Quaternion*,const uint8_t*)
Void init_twi(void)
void GetGravity(VectorFloat*,Quaternion*)
Void read_sensors(void)
void GetYawPitchRoll(ypr,Quaternion*,VectorFloat*)
Void translate(accel_t_gyro_union, accel_t_gyro_union,
accel_t_gyro_union)
void loadBuffer(uint8_t*,accel_t_gyro_union)
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
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Sensor Data Conversion
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
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 aren’t 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
Power Supply
• Two different supplies are needed
• Microcontroller and sensors
• Rated at 3.3v
• Servos
• Rated at 6v
Power Supply
•
Initial plan
•
Battery Pack
•
•
6v
Limitations
•
Current
 Click to edit the outline text
format
 Second Outline Level
 Third Outline Level
Fourth Outline Level
Fifth Outline Level
Sixth Outline Level
Seventh Outline
Level
Eighth Outline
Level
New Plan
• Power plug through the wall
• Advantages
• Limitless power supply
• Configurable for high current
• Disadvantages
• Bulky
• Increase costs
• 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
Combine 2 power supplies in one using a shared dc power bus
and dc-to-dc regulator
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
PC 350 W
P/S driving
120V 18 amps
AC in at 5 volts
3.3 Volts
Base
Servo
Shoulder
elevation
Servo
Elbow
rotation
Servo
Elbow
elevation
Servo
Wrist/
Forearm
rotation
Servo
Wrist
elevation
Servo
Gripper
Servo
LD1117AV33
MCU
Gyro
Bicept
Gyro
Forearm
PC
Power
Supply
Connection board
5V to 3.3V Voltage Regulator
Gyro
Hand
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
Budget