Simple robotic arm with a joystick controller

Intro

Simple robotic arm with a joystick controller is a project I made for teaching robotics in high school. The design is intentionally simple and there is a lot of room for improvement, but the basic parts work as intended.

The robotic arm itself has 3 degrees of freedom and a gripper as the end-effector. The joystick has potentiometers in the joints so when you place it in a pose the arm will also move into that pose. The pushbuttons at the top of the joystick are for opening and closing the gripper.

Below you can find detailed instructions on how to build the arm and considerations for printing.

Parts

Provided here are the 3D models of the mechanical parts needed to build the arm:

Gripper:

• gripper base - holds all the parts
• servo pincer - this one is fixed to the servo
• free pincer - this one follows the movement of the servo pincer
• pincer bar - a small bar that ensures that gears of pincers mesh together

Arm:

• upper link - the top-most link, has a slot for the gripper
• lower link - together with upper link allows for 2 DOF rotating around the Y axis
• base lid - turns around the Z axis
• base - holds everything together

Joystick controller:

• base - holds the pot for Z axis rotation
• L-link - holds the first pot for Y axis rotation
• lower link - holds the second pot for Y axis rotation
• upper link - holds two pushbuttons that control the gripper of the arm

Printing

Provided here are STL and STEP files. All the STL models are oriented as they should be printed, no modifications are needed.

Several parts have holes with sacrificial bridging – you will need a spanner or other metallic sharp object to punch through the single layer of plastic:

• base of the arm – holes for M3 screws
• lid of the base – one hole for M3 screw
• lower arm link – two holes for M2 screws and one M3
• upper arm link – two holes for M2 screws
• gripper base – two holes for M2 screws and one M3
• servo pincer – one hole for M2 screw
• pincer bar – one hole for an M2 and M3 screw each

The upper link of the joystick has tiny custom supports between the covers for buttons. They will easily break if you hold one of the covers in place and press in the other. Use a scalpel to cut them away if they are stubborn.

The gripper base needs supports for the upper lip of the slot which fits with the upper link of the arm. There is just no way to orient that piece nicely, I'll design custom supports in another version. I recommend using tree supports only on that detail of the part.

The parts have been tested with PLA and PETG but they should print fine with other types of plastic. Use 0.3 mm layer height as there is no advantage to using finer layers, it will only take longer.

Instructions on how to build

…coming soon