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:
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