Autonomous Gripforce Stabilizer Robotic Arm

Introduction: Autonomous Gripforce Stabilizer Robotic Arm

The Autonomous Gripforce Stabilizer Robotic Arm is a robot arm capable of applying the exact amount of pressure needed to pick up any object without breaking nor dropping it, as you can see in the video. It is first demonstrated in manual mode and again with the autonomous grip force enabled to show the difference.


The project is based around PhantomX Pincher Robot Arm Kit Mark II priced at $379.95.

in addition to this kit you will need the following components.

Step 1: Component List

  1. Robot Geek Large Workbench x 1 $8.95
  2. RobotGeek Joystick x 1 $5.95
  3. RobotGeek Rotation Knob x 1 $4.95
  4. RobotGeek LED Driver x 2 $7.90
  5. .5 Inch FSR Kit x 2 $29.90
  6. RobotGeek Pushbutton x 1 $2.95
  7. RobotGeek Slider x 2 $13.90
  8. M3 x 6mm screw x A LOT
  9. M3 stand offs x A LOT
  10. M3 screwdriver

Totalling this project around $400-$500 depending if you use these exact parts or similar.

Step 2: Assembly Guide

The link to assembling the PhantomX Pincher can be found here.

When the arm has been assembled, the I/O devices is mounted on the workbench as shown i the first picture. The base plate from the robot kit is removed and the Arm is mounted onto the workbench along with the Arbotix-M controller board.

Each component takes 8 x M3 6mm screws and 4 x stand offs to securely mount to the workbench.

You will need a total of 8 jumper cables to connect I/O from the workbench to the controller board. Additionally you will need 2 jumper cables to connect to the FSR board mounted on the Arm itself. The FSR boards are mounted on servomotor 2 as shown in the second picture.

Step 3: Wiring Up the Arbotix-M

Connecting to the board is done with 3pin jumper cables. Each I/O unit requires 1 cable except the joystick, it requires 2 cables. It is important to notice where ground is located on each I/O unit when connecting it to the board. Ground is noted G on the I/O from RobotGeek.

A0: Vertical joystick

A1: Horizontal joystick

A2: Analog slider (this will be for the height)

A3 Analog slider (this will be for the gripper)

A4: Rotation knob

A5: FSR kit (this will be the top pressure sensor)

A6: FSR kit (this will be the bottom pressure sensor)

D0: Push button

D1: LED driver

D2: LED driver

3-pin DYNAMIXEL port: Servomotor 0

FTDI port: FTDI to USB cable (for programming purposes only)

It is important to jump J1 and J2 and the Power Selection Jumper should be set to VIN to take power from the power supply.

Step 4: Programming

With the FTDI cable connected to your computer with Arduino 1.0.6 installed.

To upload to the arduino board:

  1. Open file: AutonomousGripforceV1.ino
  2. Click on the upload arrow in the top left corner
  3. Open the serial monitor in the top right corner

If the program is uploaded successfully you should see the following in the serial monitor:

  • Serial communication establised
  • Variables initialised
  • Robotic system ready

If this message does not show up but the program have been uploaded succesfully, reset the board.

If the program does not upload, check your connections and ensure that the correct board and COM port is selected.

The board should be: ArbotiX and the COM port will depend on your computer.

If it is not possible to select the given board, go back and follow the PhantomX pincher guide to setup the arm here.

Step 5: Controls

The Arm will start up in manual mode, meaning that YOU have full control of the gripper with the horizontal analog slider. The software ensures that the servos will not try to destroy itself nor other parts of the system.

  • The joystick has two axis of movement, a vertical and horizontal. The vertical movement is used to control the distance of the robot arm from the center of servomotor ID2 to the center of servomotor ID4. The horizontal movement is for controlling the tilt of the tool. The software included keeps the tilting angle fixed. The control is done with the right thumb.
  • The knob controls the base angle. The base angle can be changed so the Arm is able to work in a 3D area. The control is done with the left hand.
  • The vertical slider is used to control the height of arm. The variable is set in the software and keeps the height fixed.
  • The horizontal slider is used to control the gripper, if the Arm is in manual mode. In automatic mode, the gripper applies perfect pressure automatic.
  • The button is used to change between automatic grip mode and manual grip mode. The button also functions as a reset circuit if it is held for 5 seconds or more.
  • The automatic mode uses the pressure sensors to determine the correct pressure for any given object. If both sensors are active, the object is held in place. If the object slides and the top sensor no longer is active, it applies more pressure. If none of the sensors are active the robot arm returns a “dropped object” error and the operator will have to find the object again. The pressure control is done so that an object will be held with no more pressure than necessary.

Step 6: Test

  1. Place any object to pick up, make sure the object fits between the gripper in a fully open position.
  2. Guide the robot arm to the object with the joystick and height slider.
  3. Close the gripper firmly onto the object and move the object to another location.
  4. Open the slider fully and press the push button.
  5. Let the automatic system apply pressure.
  6. Move the object around, notice the object does not fall nor change height/reach/tilt without interaction from YOU.

The video demonstrates the functionality of the Autonomous Gripforce Stabilizer Robotic Arm.

Sensors Contest 2016

Participated in the
Sensors Contest 2016

Automation Contest 2016

Participated in the
Automation Contest 2016

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    4 years ago

    Very nice! This looks like a great setup, well done.