Reference position movements for robotic arm

[hyzentry]

Hi guys!

Currently I'm making a robot program for a 5 DOF robotic arm. In the program, I want to make an automatic function in the void loop(){}, which contains the robotic arm moves to his reference position, when the program begin. Thanks for the reference position, we know where the robot arm locate in the space, we can place the robotic arm in the space.

I know the joint angles of the reference position, I can write that thing in the program. But, if I want to do the movement from the current postion to the reference position, somehow I have to read the datas about the current joint angles to the Arduino. It can be a sensor for this task. But I don't know which type of sensors can be useful for these tasks or stuffs like that.

Can anyone have any tips or examples which sensor can be useful for angle measurements (exactly for joint angle measurements)? About the examples, I think about exact types, prototypes, or names, not generalIy speaking! I'll be so grateful, if anyone can help me, it's very important for me!

Thanks for help in advance!

Have a nice day for all of you!

[DrDiettrich]

What motors do you use? Servo motors use absolute angles, no reference point required.

If the initial position is unknown you need limit switches at one end of the path of each motor. Then move the motor into that direction until the switch comes ON. For the point of reference move back slowly until the switch goes OFF again.

[johnwasser]

If you want to know the current position after power has been lost, you will need some kind of absolute angle encoder. One relatively inexpensive form is an AS5600 magnetic rotary encoder.