Hello everyone! I am interested in purchasing a desktop robot arm in order to have it around and conduct experiments. Well, the biggest issue is that because I want to develop controllers for it, it is essential that it comes with joint sensors that can provide the angle of each joint as feedback. Are there any such robot arms that are also affordable (for example that cost maximum 300 dollars) ? Does, for example, the LittleArm Big Full Robotic Arm Kit comes with sensors for the joint angles ? Any idea would be great. Thank you in advance!
Hello @teo_protoulis and welcome to the RobotShop community,
What exactly do you mean by developing controllers for the arm?
Most (if not all) robotic arms use servo motors on each joint whose positions must be calibrated. The positions are then controlled by a microcontroller, however, not all servos provide position feedback to the microcontroller so for most hobby arms it is simply assumed that the servo has reached the commanded position (but this is not verified). You can find more information about this here:
If you want a robotic arm with position feedback then you should buy an arm that has servos with feedback. Unfortunately, the one you mentioned does not have feedback nor do any of the arms under 300 dollars in the store. So it is likely that you will need to increase your budget, if this is possible then an excellent option is this arm:
Which includes smart servos that not only provide position feedback but also voltage, current, temperature and more.
I hope this information can help you
Let us know if you have further questions
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Hello and thank you for the answer. By “developing controllers” I meant the control schemes (PID, state feedback controller) which regulate the error between a reference trajectory and the actual position of each angle. Control theory to be specific. This is why I would like feedback regarding the position of each joint. However, your answer is quite good, gave useful insights. Thanks again!
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Oh I see, then if you are interested in the arm I suggested these topics might help you:
Thank you very much for your time and help! Will check them out and consider everything!
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Hi @teo_protoulis
if you have a tight budget, you can open (any) cheap servo and solder some wires to the internal potmeter (wiper and GND will do) to get closed loop feedback. That’s what I did here.
The beauty of robotics is you can just replace everything as the robot develops so that the machine becomes more capable. Try this as a starting platform.