More documented in my BLOG: http://lamjonah.no-ip.info/wp_tech/?cat=20

Introduction of "ThisArm" Firmware

I put this hobby project open-source with a view to change the close source nature of Robot Arm firmware. More detail on calibration steps was included in the document "MainDocumentWithCalibrationSteps.docx"

This Firmware aim to provide a higher level of automation and user interaction with hobby level robot arm. This firmware is compatible with Robot Arm that replicate kinematic of ABB IRB460. Existing example in the market/open source world include:

• MeArm
• EEZYbotArm
• EEZYbotArm MK2
• And a lot more in E-bay, Taobao¡K¡K

Feature in this version include:

• Utilize the calibration data, convert human-understanding angle to RC-servo signal
• Invert kinematic to calculate desirable angle of Left, Right Servo from shoulder and elbow angle
• Interaction with robot arm with Mechanical Encoder with push button.
• Control of Robot arm by 4 potentialmeter
• G-code interpreter
  • Able to automate motion of arm by any G-code senders in the internet:
    • https://chrome.google.com/webstore/detail/gcode-sender/ngncibnakmabjlfpadjagnbdjbhoelom
    • https://github.com/MarginallyClever/GcodeSender

Hardware Requirement of this Firmware

• Computer with Arduino IDE 1.6.9 (or higher version) set-up
• Arduino UNO (or any higher grade model like Arduino Mega Uno)
  • This is the brain
• Encoder with Push button
  • This is a great human computer interaction interface
  • This would make your life much more easier during calibration
• RC-servo based Robot arm share the same kinematic of ABB IRB460

Optional Hardware

• Arduino Sensor shield V5 (save you a lot of time when wiring the servo motors and others)
• Female Dupont Cable (save you from soldering)
• Linear Potentialmeter (4 of them, each for one dimension)
  • Beware do not use logarithmic potentiometer

Default pin assignment

You can change the pin assignment as you want after you understand the code. The following is the default pin assignment:

Pin	Function of pin	Defined location
10	Base servo (a.k.a. middle servo)	Procedure "AngularServoInit()" in "AngularServo.h"
9	Left servo	Procedure "AngularServoInit()" in "AngularServo.h"
6	Right servo	Procedure "AngularServoInit()" in "AngularServo.h"
5	Claw servo	Procedure "AngularServoInit()" in "AngularServo.h"
12	Encoder Channel A (Encoder1_A)	"ThisArm.ino"
13	Encoder Channel B (Encoder1_B)	"ThisArm.ino"
11	Encoder Push button (Encoder1_Click)	"ThisArm.ino"
A2	Potentiometer for Base	Procedure "initJointsControl()" of "AnalogControl.h"
A1	Potentiometer for Shoulder	Procedure "initJointsControl()" of "AnalogControl.h"
A0	Potentiometer for Elbow	Procedure "initJointsControl()" of "AnalogControl.h"
A3	Potentiometer for Claw	Procedure "initJointsControl()" of "AnalogControl.h"

Source Code Files Explained

This part aim to deliver a brief view on structure and usage of different files. Skip this part if you just want to set the arm up without more understanding.

File Name	Function
AnalogControl.h	Contain Structure that convert potential meter input to corresponding angle
AngularServo.h	Contain Logic that convert input angle to Servo signal
ControlFunctions.h	Header for ControlFunctions.ino
ControlFunctions.ino	Contains function for different system stage that supposed to put into LOOP() for getting user's input and deliver servo output
CoordinateControl.h	Contains coordinate management and invert kinematic logics.
DisplayFunctions.h	Header for DisplayFunctions.ino
DisplayFunctions.ino	Contains functions for different system stage that deliver debug/calibration assistance output via Serial interface
GCode.h	Header for GCode.ino
GCode.ino	Contains functions for taking G-code and convert it to arm output.
InitFunctions.h	Header for InitFunctions.ino
InitFunctions.ino	Contains Initialize functions for different machine stage
ThisArm.ino	The Main file of the This Arm software
StageContainer.h	Contains structures that help to manage different stages of the firmware.
Transformation.h	Contains functions for Linear linear interpolation

Explanation of Encoder control interface:

Available action:

• Turn
  • Increase/Decrease the parameter selected.
• Pushdown and Turn
  • Increase/Decrease the parameter selected in a larger step
• Click
  • Switch selected item (Except G-code and Analog Control Stage)
• Double Click
  • Button was clicked twice within "DoubleClickInteral_ms" (10ms by default)
  • Execute DoubleClick Routine (For change of machine Stage)

Reference:

• GCode CNC Demo by MarginallyClever
  • https://github.com/MarginallyClever/GcodeCNCDemo