Petoi Doc Center
🇺🇸English
🇺🇸English
  • Welcome to Petoi Doc Center
  • Getting Started Guide
  • 🙋‍♂️FAQ(Frequently Asked Questions)
  • Petoi robot joint index
    • Joint Pins on NyBoard
      • Nybble
      • Bittle
    • Joint Pins on BiBoard V0
      • Bittle X
      • Bittle X+Arm
    • Joint Pins on BiBoard V1
      • Bittle X
      • Bittle X+Arm
      • Nybble Q
  • Bluetooth Connection
    • BiBoard
    • NyBoard
  • Upload Firmware
    • NyBoard
    • BiBoard V0
    • BiBoard V1
  • Joint Calibration
  • Infrared Remote
    • Remote Controller
  • Mobile App
    • Introduction
    • Calibrator
      • Nybble
      • Bittle
    • Controller
  • Desktop APP
    • Introduction
    • Firmware Uploader
      • NyBoard
      • BiBoard V0
      • BiBoard V1
    • Joint Calibrator
      • NyBoard Preparation
      • BiBoard Preparation
      • Nybble
      • Bittle / Bittle X
        • Bittle (NyBoard)
        • Bittle X (BiBoard V0)
        • Bittle X (BiBoard V1)
      • Bittle X+Arm
        • BiBoard V1
        • BiBoard V0
    • Skill Composer
      • NyBoard Connection
      • BiBoard Connection
      • Interface
        • Nybble
        • Bittle / Bittle X
        • Bittle X+Arm
    • Tools
  • Block-based programming
    • Petoi Coding Blocks
      • NyBoard Preparation
      • BiBoard Preparation
    • Block-based Coding Curriculum - Learn Quadruped Robotics for Beginners
    • Python coding mode in Mind+
    • Generic Arduino Uno Blocks
    • Install Mind+ on Chromebook
  • Arduino IDE
    • Upload Sketch for NyBoard
    • Upload Sketch for BiBoard
    • Calibrate the joints with Arduino IDE
    • Serial Monitor
    • C++ Curriculum: Learn Quadruped Robotics for Beginners
    • Install Arduino IDE on Chromebook
  • Free Curriculum
    • 📚Download
  • APIs
    • 🖇️Serial Protocol
      • Feedback servos
      • Nested task queue and signal generator
    • 🐍Python API
    • 🐛8266 MicroPython controller
      • Run MicroPython on ESP8266
      • Setup WebREPL
      • Using the ESP-NOW protocol
    • 🦎8266 Arduino C Controller
    • ©️C++ API
    • 🍓Raspberry Pi serial port as an interface
      • For BiBoard V1
    • 💻Set up Development Environment on Chromebook
    • 🤖ROS
  • Nyboard
    • Overview
    • NyBoard V1_0
    • NyBoard V1_1 & NyBoard V1_2
  • BIBOARD
    • BiBoard V0 Guide
    • BiBoard Extension Hat
    • Demo Applications
      • 1.GPIO port
      • 2.Serial port
      • 3.Analog-digital converter
      • 4.Digital-Analog Converter
      • 5.EEPROM (Electrically Erasable Programmable read only memory)
      • 6.Gyro IMU(MPU6050)
      • 7.Infrared remote control
      • 8.PWM(Pulse Width Modulation)
      • 9.Servo(under construction)
      • 10.Classic Bluetooth serial port SPP
      • 11.Bluetooth low energy (BLE) serial port pass-through
      • 12.File system SPIFFS
      • 13.Add hardware partition configuration option in Arduino IDE
      • 14.Play MP3
      • 15.The usage of Wi-Fi OTA(Over-The-Air)
    • BiBoard V1 Guide
  • Communication Modules
    • Introduction (For NyBoard)
    • USB Uploader (CH340C or CH343G)
    • Dual Mode Bluetooth
    • WiFi module ESP8266
      • ESP8266 + Python Scripts Implement wireless crowd control
  • Extensible Modules
    • Introduction
    • MU Camera
    • Ultrasonic Sensor
    • Light Sensor
    • Touch Sensor
    • Gesture Sensor
    • PIR Motion Sensor
    • IR Distance Sensor
    • Voice Command Module
    • Petoi AI Vision Module
    • Advanced development and application of AI vision modules
      • Model Training
      • Model quantification
      • Model deployment
      • Training on the COCO DIY dataset
    • Robot Arm
      • Upgrade your older Bittle/Bittle X for the robotics arm gripper
    • 🎮Joystick with Micro:Bit
  • Applications
    • Melody Creation
    • Skill Creation
    • OpenCat Imitation Tutorial
    • Programmable Puppet Character
    • Tutorial for simulating Bittle In Isaac Sim
  • History
    • Upload Sketch For NyBoard (software 1.0)
  • Technical Support
    • 💾Supporting Application and Software
    • 🔧Burn Bootloader for NyBoard
    • 🛠️Useful Tools
    • 🔋Battery
  • Useful Links 🕸
    • 🔭Home of Petoi Robots
    • 🛒Shop Coding Robots
    • 💿GitHub of OpenCat
    • 🎪PetoiCamp (Forum)
    • 📽️Petoi Robot Videos
    • 📬Users' repositories
Powered by GitBook
On this page

Was this helpful?

Export as PDF

Petoi robot joint index

PreviousFAQ(Frequently Asked Questions)NextJoint Pins on NyBoard

Last updated 3 months ago

Was this helpful?

We humans and many other legged animals have many joints. They give us the freedom to move in many ways. Though it's difficult to reproduce those complex motions on a robot, we can simplify all those joints to limited numbers of actuators.

When controlling so many joints, the first thing is to index them. We can define an order according to their distance from the torso. For example, the shoulder joint is closer to the torso than the elbow joint, and the joint that let us look around is closer to the torso than the joint that let us nod. If we had tails, it would be as close as the head compared to the shoulder joints.

So we can order the joints in this way: head panning, head tilting, tail panning, tail tilting, 4x shoulder (or hip) roll, 4x shoulder (or hip) pitch, 4x elbows (or knees). For the joints in the same distance group, we can index them clockwise from the front-left corner if the body is looked at from behind.

Coordinate values and directions.

The rotation angle range of the joint servo is between [-125~125]. For the leg servo, when viewed from the left side of the robot, when the leg rotates counterclockwise from the 0-degree position around the joint center point (the screw fixing position), the angle is a positive value; clockwise rotation, the angle is a negative value; viewed from the right side of the robot, the leg rotation angle is mirror-symmetrical to the left side (when rotating clockwise from the 0-degree position around the joint center point, the angle is a positive value; Rotate counterclockwise, the angle is negative). For the robot's neck servo, looking down from the top of the robot's head, when the neck rotates counterclockwise from the position of 0 degrees around the joint center point (the position where the screw is fixed), the angle is a positive value; when it rotates clockwise, the angle is a negative value.

For the Nybble head servo (No. 1 servo) observed on the right side of the robot, the head rotates counterclockwise from the 0-degree position around the joint center point (screw fixed position), and the angle is positive; when it rotates clockwise, the angle is negative.

For the Nybble tail servo (No. 2 servo) facing the tail and looking down, the tail rotates counterclockwise from the 0-degree position around the center point (screw fixing position), and the angle is positive; when it rotates clockwise, the angle is negative.