Post on 09-Jan-2017
Making Robots with mruby
2015-12-12 RubyKaigi 2015 Yurie Yamane
Team Yamanekko
Who am I?
やまね ゆりえ(Yurie Yamane) @yuri_at_earth(only in Japanese)
a member of TOPPERS project ET robocon staff たいやき部(taiyaki-bu)
2012
2013
2014
nomitory
2015
Robots and Us
http://global.yamaha-motor.com/jp/showroom/event/2015tokyomotorshow/sp/exhibitionmodels/mgp/
“There are probably some things in this world that only I can do.”https://www.youtube.com/watch?v=EzgJWwAx8Mo
PART 1: Self-balancing Robot using LEGO EV3
闇RubyKaigi(2011)
http://gihyo.jp/news/report/01/rubykaigi2011/0001?page=7
ETロボコンAdvent Calendar 2015
http://www.adventar.org/calendars/734
ET Robot Contest• aka ET ロボコン(ET ROBOCON)
• ET means “Embedded Technology”
• To develop the advanced skills of embedded technology such as modeling, designing, and developing embedded systems
• “one-make racing” style (all robots have same designs)
EV3way: SoftwareSystem OS Language
TOPPERS/EV3RT TOPPERS RTOS C, C++
MonoBrick Linux C#
leJOS EV3 Linux Java
EV3way: Software
• mruby on EV3RT + TECS
• mrby Forum ver.
• yamanekko ver.
System OS Language
TOPPERS/EV3RT TOPPERS RTOS C + mruby
mruby-ev3rt
mruby-ev3rt demoSep. 20th, 2015 at Fukuyama, Hiroshima Pref.
Movie by A. Hirai with ET Robocon Staff@chu-shikoku
• TOPPERS（Toyohashi OPen Platform for Embedded Real-time Systems）
• TOPPERS’ Products
• Realtime Kernel
• Automotive Kernel
• Tools
• TOPPERS + TSUBAME(swallow) -> TOPAME
TOPPERS Project
とぱめ(TOPAME)https://www.toppers.jp/
Who uses TOPPERS?
http://ev.nissan.co.jp/LEAF/?pfa=01http://www.ricoh.co.jp/printer/sg/3100ke/
http://www.korg.com/jp/products/dj/electribe/http://music.casio.com/ja/products/digital_pianos/ghs/products/
https://en.wikipedia.org/wiki/H-IIBfrom: http://toppers.jp/applications.html
TOPPERS Kernel Roadmap
ATK1 ATK2 ATK3
FMP3
HRP3
ASP3
2000 2010 2020
1st generation 3rd generation2nd generation
ITRON
Automotive
FDMP
HRP
FI4
JSP
Dynamicgen.
ASP Safety
HRP2
FMP
ASPSSP
http://toppers.jp/docs/intro-invite.pdf
TOPPERS EV3RTunprivileged mode (user mode)
privileged mode (kernel mode)
http://dev.toppers.jp/trac_user/ev3pf/wiki/WhatsEV3RT
Self Balancing Robot
Inverted Pendulum
Inverted Pendulum
Inverted Pendulum
Inverted Pendulum
Inverted Pendulum
Inverted Pendulum
Inverted Pendulum
How Robot Works
Target BoardSensorsActuator
Gyro Sensor
Ultrasonic Sensor
Motor
Light Sensor
How Robot Works
Target BoardSensorsActuator
Read
How Robot Works
Target BoardSensorsActuator
Move
How Robot Works
sense
calculate
control motor
execute periodically
What’s RTOS• OS for Real Time System
• Real time system: to make much of Deadlines
• NOTICE: “Real-Time” has several meanings
• “Real-Time” in RTOS is completely different from such as “Real-time Web”
Time is Resource• In real time
system, Tasks should be done in a given time (deadline)
• RTOS manage “Time” as resources (like memories)
https://www.flickr.com/photos/arjanrichter/3886579525/
Priority of tasks
• Every tasks have their own priority
• Lower-priority tasks never execute when higher-priority tasks alive
• While higher-priority task is running, lower-priority tasks are not running (into READY status)
All tasks are mruby
main_task
balance_task
watch_task
HIGH priority
LOW priority
balancer.rb
watch.rb
app_ruby.rb
注）バランス制御に重点を置いた例。 これが正しい方法というわけではない
balancer.rbloop do forward = 30 color = colorSensor.brightness if color >= (LIGHT_WHITE + LIGHT_BLACK)/2 turn = 20 ## turn left else turn = -20 ## turn right end
pwm_left, pwm_right, *args = balancer.calculate_auto(forward, turn, GYRO_OFFSET) leftMotor.pwm = pwm_left rightMotor.pwm = pwm_right EV3RT::Task.sleepend
watch.rb
loop do break if back_button.pressed? EV3RT::Task.sleepend
app_ruby.rb## initialize sensors, motors, clock and taskstouchSensor = EV3RT::TouchSensor.new(EV3RT::PORT_1)gyroSensor = EV3RT::GyroSensor.new(EV3RT::PORT_4)leftMotor = EV3RT::Motor.new(EV3RT::PORT_C, EV3RT::LARGE_MOTOR)rightMotor = EV3RT::Motor.new(EV3RT::PORT_B, EV3RT::LARGE_MOTOR)clock = EV3RT::Clock.new()EV3RT::Task.active(EV3RT::BALANCE_TASK_ID) ## initialize balancer
loop do ## waiting button pushed break if touchSensor.pressed? clock.sleep(10)end
EV3RT::Task.start_cyclic(EV3RT::BALANCE_CYC_ID) ## start balancerEV3RT::Task.sleep ## do other tasks
Classes in mruby-ev3rtMotor
TailMotor
Sensor
GyroSensorColorSensor
TouchSensor
LED LCD Clock Serial Task
Balancer
Button
PART 2:
DIY Self-balancing Robot
DIY Self-balancing Robot
Can we make our own robots from scratch?
https://www.flickr.com/photos/84906483@N08/8747337118/
DIY Self-balancing Robot
😿🙀😸http://www.instructables.com/id/Another-Easier-Inverted-Pendulum/
Collecting Parts
Target BoardSensors Actuator
Raspberry Pi A+• Lower battery usage
than Pi B+ and Pi 2
• Works with small USB battery
• Cheeper (< $30) than Pi B+ and Pi 2
Raspberry Pi A+
😿
ARM Family
http://www.emcu.it/CortexFamily/CortexFamily.html
Pi1 Pi2
EV3STM32F4
Inverted Pendulum
How to measure an angle
Gyro Sensor
http://akizukidenshi.com/catalog/g/gK-06779/
Gyro Sensor
• ST Micro L3GD20
• 3-axis digital gyroscope
• use 8 pin DIP module by Akizuki Denshi
Gyro Sensor
😿
Gyro Sensor
🙀
Measuring the Angle
!1 !2
How to rotate wheels
DC Motor
• TAMIYA FA-130 Motor
• speed control by voltage
• IO cannot change voltage
• 3.3 V (fixed)
• → use PWM
DC Motor
😿
(Motor + Gear) x 2
Wheel x 2
Body
Tamiya 70157 Universal Plate Set
Batteries (for motors)
Batteries (for motors)
🙀
Battery (for Pi A+)
connect a sensor
?
SPI vs I2C• SPI and I2C are popular protocols
• Gyro sensor L3GD20 supports both
• SPI is more complex, but faster than I2C
• Raspberry Pi supports SPI (see “BCM2835 ARM Peripherals”) • https://www.raspberrypi.org/wp-content/uploads/
2012/02/BCM2835-ARM-Peripherals.pdf
Serial Peripheral Interface (SPI)
• Master and Slave model • In our case, Raspberry Pi is master • 4 pins (Input, Output, Clock, Select)
Demo
Gyro Testserial = Serial.new timer = SystemTimer.new gyro = Gyro.new() serial.puts("time,gyro")
MESURE_COUNTS = 45 start_time = timer.now
cnt = 0 loop do mesure_sum = 0 MESURE_COUNTS.times{ mesure_sum += gyro.read(Gyro::Y) }
omega_i = mesure_sum * 0.00875 / MESURE_COUNTS; cnt +=1 now = ((timer.now - start_time) / 1000).floor if cnt == 10 cnt = 0 serial.puts("#{now},#{omega_i}") end end
connect motors
?
PWM• Pulse-Width Modulation
• pseudo-analog signal output
http://www.electronics-tutorials.ws/blog/pulse-width-modulation.html
PWM• Raspberry Pi A+/B+/2 supports 2 PWMs
• Old Raspberry Pi B support only 1 PWM
• So we can control 2 motors (Right/Left)
Motor Driver
ST Micro L298N
Motor Driver
PWMIN1 IN2
OUT1 OUT2
MOTOR
Motor Driver
Raspberry Pi
IN1 IN2 OUT0 0 STOP
0 1 Forward
1 0 Reverse
1 1 Brake
Demo
Motor Test# in1, in2, enable, pwm0or1 motor_left = Motor.new(5,6,12,0) motor_right = Motor.new(16,20,19,1)
motor_right.drive(50) motor_left.drive(50) RSRobot.delay(3000000) motor_left.drive(200) motor_right.drive(200) RSRobot.delay(3000000) motor_right.drive(50) motor_left.drive(50) RSRobot.delay(3000000) motor_right.drive(-100) motor_left.drive(-100) RSRobot.delay(3000000) motoy_right.stop motor_left.sop
JTAG• For Debugger
• Doesn’t have to use it
• but with JTAG, we can use GDB, so it’s very helpful to debug
Pinout
Making Balancer class
Balancing Equation
power = k_1 * (Angular Velocity) + k_2 * (Angle) + k_3 * (Velocity) + k_4 * (Position)
P = K
!
! +K
✓
✓ +K
v
v +K
x
x
Angle
✓ ✓
Angular Velocity! !(fast) (slow)
Velocity(fast) (slow)vv
Position(far) (near)y asixsy asixs
Balancing Equation
power = k_1 * omega_i + k_2 * theta_i + k_3 * v_i + k_4 * x_i
P = K
!
! +K
✓
✓ +K
v
v +K
x
x
Balancing Equation
power = k_1 * omega_i + k_2 * theta_i + k_3 * v_i + k_4 * x_i
a ≒ Power v ≒ ∫ Power x ≒ ∬ Power
P = K
!
! +K
✓
✓ +K
v
v +K
x
x
Balancing EquationP = K
!
! +K
✓
✓ +K
v
v +K
x
x
= K
!
! +K
✓
X! +K
v
XP +K
x
XXP
power = k_1 * omega_i + k_2 * theta_i + k_3 * v_i + k_4 * x_i
a ≒ Power v ≒ ∫ Power x ≒ ∬ Power
Balancing Equation
theta_i += omega_i v_i += power x_i += v_i power = k_1 * theta_i + k_2 * omega_i + k_3 * v_i + k_4 * x_i
P = K
!
! +K
✓
✓ +K
v
v +K
x
x
= K
!
! +K
✓
X! +K
v
XP +K
x
XXP
Balancer classclass Balancer
def calculate(omega_i) @theta_i += omega_i # … t = @k_angle * @theta_i o = @k_omega * omega_i # … power = t + o + … # … return power, power end
end
main looploop do gyro_value = gyro.measure(Gyro::Y, MESURE_COUNTS)
pwm_left, pwm_right = balancer.calculate(gyro_value)
motor_left.pwm = pwm_left motor_right.pwm = pwm_right end
demo
まずは何か作ってみよう！
Source code
• https://github.com/yamanekko/mruby-ev3rt
• https://github.com/yamanekko/mruby-rs-robot
• https://github.com/yamanekko/raspi_robot
Thank you & Domo Arigato!
ZZZ...
You can contact us on Twitter: @yuri_at_earth Special Thanks to: @tenderlove A. Hirai with ET Robocon Staff@chu-shikoku