RubyKaigi2015 making robots-with-mruby
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This document summarizes Yurie Yamane's presentation on using mruby to make robots. It discusses using mruby and TOPPERS on the LEGO EV3 to create an inverted pendulum self-balancing robot. It then covers creating a DIY self-balancing robot using a Raspberry Pi, gyro sensor, DC motors, and a motor driver. Code examples are provided for reading sensor values, controlling motors with PWM, and implementing a balancing algorithm using a balancer class. Source code links are included for further reference.
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RubyKaigi2015 making robots-with-mruby
- 1. Making Robots with mruby 2015-12-12 RubyKaigi 2015 Yurie Yamane Team Yamanekko
- 2. 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)
- 4. 2012
- 5. 2013
- 7. 2015
- 9. 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
- 14. 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)
- 15. EV3way: Software System OS Language TOPPERS/EV3RT TOPPERS RTOS C, C++ MonoBrick Linux C# leJOS EV3 Linux Java
- 16. EV3way: Software • mruby on EV3RT + TECS • mrby Forum ver. • yamanekko ver. System OS Language TOPPERS/EV3RT TOPPERS RTOS C + mruby
- 17. mruby-ev3rt
- 18. mruby-ev3rt demo Sep. 20th, 2015 at Fukuyama, Hiroshima Pref. Movie by A. Hirai with ET Robocon Staff@chu-shikoku
- 19. • 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/
- 20. Who uses TOPPERS? http://ev.nissan.co.jp/LEAF/?pfa=01 http://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-IIB from: http://toppers.jp/applications.html
- 21. TOPPERS Kernel Roadmap ATK1 ATK2 ATK3 FMP3 HRP3 ASP3 2000 2010 2020 1st generation 3rd generation2nd generation ITRON Automotive FDMP HRP FI4 JSP Dynamic gen. ASP Safety HRP2 FMP ASP SSP http://toppers.jp/docs/intro-invite.pdf
- 22. TOPPERS EV3RT unprivileged mode (user mode) privileged mode (kernel mode) http://dev.toppers.jp/trac_user/ev3pf/wiki/WhatsEV3RT
- 31. How Robot Works Target Board Sensors Actuator
- 32. Gyro Sensor Ultrasonic Sensor Motor Light Sensor
- 33. How Robot Works Target Board Sensors Actuator Read
- 34. How Robot Works Target Board Sensors Actuator Move
- 35. How Robot Works sense calculate control motor execute periodically
- 36. 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”
- 37. 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/
- 38. 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)
- 39. 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
- 40. balancer.rb loop 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.sleep end
- 41. watch.rb loop do break if back_button.pressed? EV3RT::Task.sleep end
- 42. app_ruby.rb ## initialize sensors, motors, clock and tasks touchSensor = 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 balancer EV3RT::Task.sleep ## do other tasks
- 43. Classes in mruby-ev3rt Motor TailMotor Sensor GyroSensorColorSensor TouchSensor LED LCD Clock Serial Task Balancer Button
- 45. DIY Self-balancing Robot Can we make our own robots from scratch? https://www.flickr.com/photos/84906483@N08/8747337118/
- 48. Collecting Parts Target Board Sensors Actuator
- 49. 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
- 53. How to measure an angle
- 55. Gyro Sensor • ST Micro L3GD20 • 3-axis digital gyroscope • use 8 pin DIP module by Akizuki Denshi
- 56. Gyro Sensor 😿
- 57. Gyro Sensor 🙀
- 58. Measuring the Angle !1 !2
- 60. How to rotate wheels
- 61. DC Motor • TAMIYA FA-130 Motor • speed control by voltage • IO cannot change voltage • 3.3 V (fixed) • → use PWM
- 62. DC Motor 😿
- 64. (Motor + Gear) x 2
- 66. Wheel x 2
- 67. Body Tamiya 70157 Universal Plate Set
- 71. Battery (for Pi A+)
- 74. 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
- 75. Serial Peripheral Interface (SPI) • Master and Slave model • In our case, Raspberry Pi is master • 4 pins (Input, Output, Clock, Select)
- 76. Demo
- 77. Gyro Test serial = 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
- 78. connect motors ?
- 79. PWM • Pulse-Width Modulation • pseudo-analog signal output http://www.electronics-tutorials.ws/blog/pulse-width-modulation.html
- 80. 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)
- 81. Motor Driver ST Micro L298N
- 82. Motor Driver PWMIN1 IN2 OUT1 OUT2 MOTOR Motor Driver Raspberry Pi IN1 IN2 OUT 0 0 STOP 0 1 Forward 1 0 Reverse 1 1 Brake
- 83. Demo
- 84. 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
- 85. JTAG • For Debugger • Doesn’t have to use it • but with JTAG, we can use GDB, so it’s very helpful to debug
- 86. Pinout
- 88. Balancing Equation power = k_1 * (Angular Velocity) + k_2 * (Angle) + k_3 * (Velocity) + k_4 * (Position) P = K!! + K✓✓ + Kvv + Kxx
- 89. Angle ✓ ✓
- 90. Angular Velocity ! !(fast) (slow)
- 92. Position (far) (near)y asixsy asixs
- 93. Balancing Equation power = k_1 * omega_i + k_2 * theta_i + k_3 * v_i + k_4 * x_i P = K!! + K✓✓ + Kvv + Kxx
- 94. 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✓✓ + Kvv + Kxx
- 95. Balancing Equation P = K!! + K✓✓ + Kvv + Kxx = K!! + K✓ X ! + Kv X P + Kx X X P power = k_1 * omega_i + k_2 * theta_i + k_3 * v_i + k_4 * x_i a ≒ Power v ≒ ∫ Power x ≒ ∬ Power
- 96. 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✓✓ + Kvv + Kxx = K!! + K✓ X ! + Kv X P + Kx X X P
- 97. Balancer class class 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
- 98. main loop loop 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
- 99. demo
- 101. まずは何か作ってみよう！
- 103. 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