Servo torque to weight ratios
0.16 Hitec HS-805BB 24.5kg-cm / 152g
0.16 HS-645MG 9.6kg-cm / 60g
0.18 HXT900 1.6kg-cm / 9g
0.19 Hitec HS-805BB @7.2V maybe 29kg-cm / 152g
0.30 Robotis AX-12+ 16.5kg-cm / 55g
0.37 Hitec HS-7955TG 24kg-cm / 65g
0.42 Futaba BLS152 31kg-cm / 74g
0.44 Hitec HS-5990TG 30kg-cm / 68g
0.46 JRPROPO DS6311HV 36.5oz-in / 80g
0.52 Robotis RX-28 37.7kg-cm / 72g
0.55 Robotis RX-64 64kg-cm / 116g
0.68 Robotis EX-106 106kg-cm / 155g
0.66 VSTONE V-SERVO VS-SV410 41kg-cm / 62g
0.68 VSTONE V-SERVO VS-SV1150 115kg-cm / 170g
0.85 VSTONE V-SERVO VS-SV3310 327kg-cm / 387g
The nice trend is that as you go up in torque your torque to weight ratio also goes up. So bigger robots should actually be easier to make than smaller robots. However what I also should really factor in is how much weight is required to power the servo. You could run a entire HXT900 biped on 2 A123 cells, but you might need on average a cell for each VS-SV3310 ( just a guess. )
Another thing going for the bigger bots is that the computer and censor bits take up a much smaller percentage of the over all mass.
Now for laughs.. http://www.z425.com/robot/diy-servo-project/
1.63 BILLY CRAZY DIY SERVO 594kg-cm / 365g ( no electronics )
I came up with those numbers years ago. Soon I'll finally get around to building one and see what it actually ends up at. I think I want to swap out the motor with a smaller one for physical size and amp reasons. The ratio should still end up above 1.0 with electronics. Which would be awesome.
0.16 HS-645MG 9.6kg-cm / 60g
0.18 HXT900 1.6kg-cm / 9g
0.19 Hitec HS-805BB @7.2V maybe 29kg-cm / 152g
0.30 Robotis AX-12+ 16.5kg-cm / 55g
0.37 Hitec HS-7955TG 24kg-cm / 65g
0.42 Futaba BLS152 31kg-cm / 74g
0.44 Hitec HS-5990TG 30kg-cm / 68g
0.46 JRPROPO DS6311HV 36.5oz-in / 80g
0.52 Robotis RX-28 37.7kg-cm / 72g
0.55 Robotis RX-64 64kg-cm / 116g
0.68 Robotis EX-106 106kg-cm / 155g
0.66 VSTONE V-SERVO VS-SV410 41kg-cm / 62g
0.68 VSTONE V-SERVO VS-SV1150 115kg-cm / 170g
0.85 VSTONE V-SERVO VS-SV3310 327kg-cm / 387g
The nice trend is that as you go up in torque your torque to weight ratio also goes up. So bigger robots should actually be easier to make than smaller robots. However what I also should really factor in is how much weight is required to power the servo. You could run a entire HXT900 biped on 2 A123 cells, but you might need on average a cell for each VS-SV3310 ( just a guess. )
Another thing going for the bigger bots is that the computer and censor bits take up a much smaller percentage of the over all mass.
Now for laughs.. http://www.z425.com/robot/diy-servo-project/
1.63 BILLY CRAZY DIY SERVO 594kg-cm / 365g ( no electronics )
I came up with those numbers years ago. Soon I'll finally get around to building one and see what it actually ends up at. I think I want to swap out the motor with a smaller one for physical size and amp reasons. The ratio should still end up above 1.0 with electronics. Which would be awesome.
