9 ms·

The biggest problem is they are using RC style servos. This is why all the arm motions are jerky and lack precision. What this means: No force feedback on pos

The biggest problem is they are using RC style servos. This is why all the arm motions are jerky and lack precision. What this means: No force feedback on positioning. Jerky motion due to actuator steps. Limited precision. Terrible slow motion control performance. Fast movements will look better. Inability to solve problems with software. Basically think of all the joints like those cheap thermal camera screens that are at 320 x 240 resolution. For rough work or finding some sort of oddity your good, but anything precise you need to spend real money. It's a pretty cool toy, but don't go buying this expecting that much.

quertyrecord74 15d ago
whats the alternative to servos that give precise movement and control via software.
- cpgxiii 15d ago
  Any of the integrated actuators on the market (e.g. Cubemars, zeroerr, myactuator, many more) do proper control and feedback.
amelius 15d ago
Well, if it can fold my laundry and do the dishes, then jerky movements don't matter to me. I suppose precision can be fixed with camera feedback. And those force feedback actuators use significantly more power.
- spwa4 14d ago
  For the love of god. You're going to hurt yourself. You don't need to be a robotics expert but, you want your motors to not jitter? Use a robotics library! PLAN the trajectory. The jerk will disappear and lots of other things will disappear. Your trajectory generator will say "sorry, Dave" (throw an exception, they're mostly C++), rather than the robot crashing or hurting you or the battery catching fire (which these servos can easily cause). Basic blind servo control is cool for RC cars but for something this size it definitely isn't. Don't send raw step changes to the servo positions. Use a trajectory generator that enforces position/velocity/acceleration/jerk limits, ideally use measured joint state (but not available on hobby servos) rather than assuming commanded position was reached, and add hardware-level current/torque/fault limits and a real emergency-stop strategy. Torque/current limiting, if necessary in software, is the minimum here.
  - amelius 14d ago
    If you're worried about safety: compliance can be implemented outside of the motor, e.g. with springs.
    - spwa4 14d ago
      Yes, at 100x the cost, so anybody taking the route of using servos is not going to do that either. Plus it's 2026, not 1960, use software.
firmretention 15d ago
It reminds me of how the first Terminator moved because of the stop motion effects.
4d4m 14d ago
Is it possible to use the PWM signal from some RC servos to measure feedback at the motor?

quertyrecord74 15d ago

whats the alternative to servos that give precise movement and control via software.

cpgxiii 15d ago
Any of the integrated actuators on the market (e.g. Cubemars, zeroerr, myactuator, many more) do proper control and feedback.

amelius 15d ago

Well, if it can fold my laundry and do the dishes, then jerky movements don't matter to me. I suppose precision can be fixed with camera feedback. And those force feedback actuators use significantly more power.

spwa4 14d ago
For the love of god. You're going to hurt yourself. You don't need to be a robotics expert but, you want your motors to not jitter? Use a robotics library! PLAN the trajectory. The jerk will disappear and lots of other things will disappear. Your trajectory generator will say "sorry, Dave" (throw an exception, they're mostly C++), rather than the robot crashing or hurting you or the battery catching fire (which these servos can easily cause). Basic blind servo control is cool for RC cars but for something this size it definitely isn't. Don't send raw step changes to the servo positions. Use a trajectory generator that enforces position/velocity/acceleration/jerk limits, ideally use measured joint state (but not available on hobby servos) rather than assuming commanded position was reached, and add hardware-level current/torque/fault limits and a real emergency-stop strategy. Torque/current limiting, if necessary in software, is the minimum here.
- amelius 14d ago
  If you're worried about safety: compliance can be implemented outside of the motor, e.g. with springs.
  - spwa4 14d ago
    Yes, at 100x the cost, so anybody taking the route of using servos is not going to do that either. Plus it's 2026, not 1960, use software.

firmretention 15d ago

It reminds me of how the first Terminator moved because of the stop motion effects.

4d4m 14d ago

Is it possible to use the PWM signal from some RC servos to measure feedback at the motor?