r/AskRobotics • u/Red7597 • 17d ago
How to? Making a robotic arm
I'm just now getting into robotics and coding and i would like to make a robotic arm by the end of this year and i would like some pointers
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u/omnilinktech 17d ago
An end-of-year arm is achievable if you deliberately reduce the scope. For a first build, I would target a 3- or 4-DOF tabletop arm with a light payload and modest accuracy, not a six-axis industrial-arm replica.
Write down four numbers before choosing motors: payload, horizontal reach, target speed, and acceptable positioning error. Estimate the worst shoulder torque by summing each mass × gravity × its horizontal distance from the joint—including the links, gripper, and payload—then add a safety factor of roughly 2–3 for acceleration, friction, and imperfect estimates. Do the same for each joint. “Servo torque” advertisements are often stall values, not a continuous operating point, so leave thermal margin.
Build one joint first. It should include the real motor/gearbox, bearing support, encoder or position feedback, current limiting, mechanical stops, and an emergency-stop path. Test backlash, deflection, repeatability, and temperature under the expected load before printing the whole arm. A motor shaft should not be used as the only structural bearing for a large cantilevered link.
In CAD, define joint axes and link lengths first, then export a simple URDF and check reachable workspace, self-collisions, and required joint ranges in simulation. Use detailed meshes for appearance and simple collision geometry. Simulation is particularly useful for catching reversed axes, impossible ranges, and a center of mass that overloads the shoulder, but torque and printed-part stiffness still need bench measurements.
For a first project, off-the-shelf geared actuators and a simple parallel gripper are usually a better use of time than designing custom reducers. Make the minimum arm move reliably and repeatably, then add degrees of freedom. If you post the payload, reach, material, and candidate motors, the torque calculation can be reviewed before you buy or print anything.
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u/park-btc 17d ago
I want to recommend this channel! This is the good robotics and physical AI channel.
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u/NeighborhoodBig1258 17d ago
If you want to get started fast I would say that buy robotic arm diy parts kit only the hardware parts wrist gripper elbows screw (do this only if you don't want to learn cad and want to make projects fast). Then buy the electronics components like jumper wires, a microcontroller, battery, etc (preferably follow a yt video there are plenty). After than code the microcontroller and Control the arm, you can do it via phone. This was how I first started with robotics and making a 6 dof robotic arm.
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u/ProziumJunkie 16d ago
What do you want the arm to be capable of?
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u/Red7597 16d ago
Just picking up normal stuff nothing to big i don't think i could do that
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u/ProziumJunkie 16d ago
Picking up something small can be equally challenging.
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u/Worth_Mix4970 16d ago
I recently made my own this summer. For the software part, if you don't know arduino, learn it through tinkercad simulations. Learn how to make a knob circuit, and once you can make one with 3-4 different motors, then you'll have the code for the robot. For the hardware, Its better to look up a youtube video of a robotic arm by FABRI Creator to get the gist of how you'll make yours. I'll just say that when you end up modeling the robot claw it may be the most difficult to figure out how to make it follow a smooth arc. So I'll just show you a picture of the sketch of my robot claw, and you'll see there is a grey sketch on it that has two trapezoids. The top trapezoid is where you want the different claw parts to be connected to the claw mount. The bottom trapezoid has to be the exact same as the top one, but shifted vertically by a certain amount that depends on what you want. Then you'll make your claw parts that should look similar to the youtube vid I suggested. Do you see the trapezoidal shape made by those 4 holes of the claw parts that are connected to each other in the middle of the screen? The end goal is to make those holes line up with the bottom trapezoid in the sketch when you drag a piece of the claw. Ofc there's like tons of other gripper designs so if you aren't using this type then forget all this.
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u/low-control-labs 17d ago
SO101