#robotics Logs

Jun 28 2020

12:38 AM rue_shop2: mun, tape
12:44 AM rue_shop2: it keeps the springs from resonating
12:44 AM rue_shop2: "vibration damper"
12:44 AM rue_shop2: a rubber sleeve is ideal, but tape works fine
02:21 AM mun: Anyone know why most arms prefer using a large J2 motor than using a counterweight?
02:21 AM mun: Do counterweights somehow complicate the design?
02:41 AM Jak_o_Shadows: counterweights increase intertia?
03:17 AM veverak: counterweights increase weight
03:17 AM veverak: and not linearly
03:18 AM veverak: if last joint uses counterweight, it's weight +- doubles
03:19 AM veverak: but this increased weight A. has to be lifted by other joints B. the counterweigh on other joints has to be that much heavier
03:20 AM veverak: so it is 2^x thing
03:20 AM veverak: so, you end up with much heavier ARM that has brutal inertia
03:26 AM Jak_o_Shadows: Yeah. I was mostly thinking about the first joint, but yeah.
03:27 AM mun: why 2^x?
03:31 AM mun: rather than using an extra weight, the J3 motor could be shifted down past J2 and use J3 motor has counterweight, right?
04:54 AM ThomasEgi: anyone ever tried to use wire based actuators on a small robotic system and use actual counterweights dangling on the actuator wires under the desk?
05:03 AM veverak: mun: not sure what J2/J3 is
05:03 AM veverak: anyway
05:03 AM veverak: yeah, if you do not add weight, using what weight you got as counterweight is a good idea
05:03 AM veverak: meaning: do not add anything, just spread the weight
05:03 AM veverak: :)
05:04 AM mun: sorry, J2 as in shoulder, J3 as in elbow
05:04 AM mun: i see many arms shifting the elbow motor down near shoulder, but never past it
05:06 AM veverak: I saw some that put the motors past it
05:07 AM veverak: multiple motors actually
05:07 AM mun: oh?
05:07 AM veverak: as on that joint were joints that actuated following segments via belts or gears
05:08 AM veverak: some KUKA model
05:08 AM veverak: https://www.eurobots.net/media/robot/KR_6_2.jpg
05:08 AM veverak: this idea more or less, but different model
05:08 AM veverak: can't remember where I saw it
05:09 AM mun: oh, i remember this
05:09 AM mun: but still, motors don't go past the shoulder
05:15 AM mrdata_ is now known as mrdata
11:59 AM FloridaMan_ is now known as Ulyana
11:59 AM Ulyana is now known as FloridaMan_
11:59 AM FloridaMan_ is now known as Ulyana
11:59 AM Ulyana is now known as Lakota
12:00 PM Lakota is now known as marcuse