5Dof Robotic arm pick and place w OpenMV M7

Projects Programming
1

Hey folks. I'm currently building a project and im really stuck in program development part any help or guidance is appriciated.

The main project is to assembly a robotic arm (5Dof) as grabber signed as joint and implement machine vision with help of OpenMV M7 micropython camera and Arduino microcontroller and execute pick and place.

For the build im using the following:
Arduino Mega 2560
OpenMV M7
Adafruit PCA9685 servo driver
MG996R servos
5dof robotic arm metalic frame (ebay)

After calibrating servos andconnecting the camera module with the arduino through serial Uart i'm able to receive objects X Y coordinates in sting to arduino and after i can store them in Vars but im having hard time to compute the Inverse kinematics calculations algoritm in order grapper to reach the desired position. As i imagine that the OUTPUT of IK should be an angle in degrees for each servo which i should feed to pwn servo driver. Thanks in advance.

2

Please read How to use this forum and post your full program and details of the hardware including a schematic if applicable

3

It looks like a 5DOF arm doesn't have an elbow. That's going to make it impossible to lift things straight up and place them straight down.

Except for the vertical axis of the base, the arm moves in a single plane. To get to a specific position:

  • Calculate the angle that is from the base and set the base servo to that angle. Simple trigonometry.
  • Calculate how far from the shoulder axis to the position and set the wrist angle so the shoulder/wrist/gripper triangle has the right hypotenuse. Again, simple trig. Knowing the three sides of the triangle you can calculate all of the angles.
  • Set the shoulder angle so the gripper, now a known distance from the shoulder pivot, is at the desired height. Again, simple trig. You know all of the sides so you just need to calculate an angle.

You really need a 6DOF arm. For pick-and-place you need to be able to align the gripper with a piece, pick it straight up, change it's orientation, and place it straight down. You just can't do that when the only way to change reach is to tilt the gripper.