This page (revision-54) was last changed on 2021-10-02 05:56 by Murray Altheim

This page was created on 2021-03-29 18:18 by Murray Altheim

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Page References

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Mars Rover
MarsRover

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At line 29 changed one line
I've found three potential suppliers of motors. It's unclear exactly at this point what my unloaded speed (RPM) and torque (oz-in or kg-cm) should be to support the robot at a reasonable target velocity. The NASA Mars rovers move very slowly, for reasons due to the communication distance to and from Mars, caution (no repairs possible), etc. I'd like the new robot to have roughly the same top speed as the KR01, so I'm basing the new spec on that of the 9V OSEPP 25mm DC motors, about 60m in length, with 8500RPM motors geared down 45:1 to 189RPM. I can't find a torque rating but we'll assume that a motor in that ballpark or maybe a bit stronger would be okay. I'll have to do some tests on the KR01 to actually measure its top speed.
I've found three potential suppliers of motors. It's unclear exactly at this point what my unloaded speed (RPM) and torque (oz-in or kg-cm) should be to support the robot at a reasonable target velocity. The NASA Mars rovers move very slowly, for reasons due to the communication distance to and from Mars, caution (no repairs possible), etc. I'd like the new robot to have roughly the same top speed as the KR01, so I'm basing the new spec on that of the 9V OSEPP 25mm DC motors, about 60m in length, with 8500RPM motors geared down 45:1 to 189RPM. I can't find a torque rating but we'll assume that a motor in that ballpark or maybe a bit stronger would be okay. I'll have to do some tests on the KR01 to actually measure its top speed.
At line 31 added 3 lines
ServoCity sells an off-road style robot kit called The Warden which uses the 4.3 inch off-road tires and is roughly the same
size as the planned rover, and it's using four of the 195RPM Precision Planetary Gearmotors that I've ordered, so hopefully
this is an indication that my choice isn't too far off.
At line 34 changed one line
TBD
At line 45 added 8 lines
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|| Description || Length || Shaft || Voltage || RPM || Gear Ratio || Stall Current || Stall Torque || Encoder CPR || Price (US$) || Notes
| [OSEPP DC Motor-25 Wheel Kit|https://www.osepp.com/mechanical-parts/124-dc-motor-25-wheel-kit] | 59mm | 4mm | 9V | 185 | 45:1 | | 1.5Kgf.cm | 494 | $19.99 | problematic encoder mount; comes with wheel and tire
| [47:1 Metal Gearmotor 25Dx67L mm HP 12V with 48 CPR Encoder|https://www.pololu.com/product/4845] | 66.5mm | 4mm | 12V | 210 | 45:1 | 5.6A | 165 oz-in | 2248 | $36.95 | 25mm diameter, bronze bushing output shaft
| [ServoCity 195 RPM Premium Planetary Gear Motor w/Encoder|https://www.servocity.com/195-rpm-premium-planetary-gear-motor-w-encoder/] | 64.8mm | 4mm | 12V | 195 | 61.6:1 | 4.9A | 6.8kgf-cm | 740 | $31.99 | 22mm diameter, ball-bearing output shaft
| [ServoCity 5202 Series Yellow Jacket Planetary Gear Motor|https://www.servocity.com/5202-series-yellow-jacket-planetary-gear-motor-50-9-1-ratio-117-rpm-3-3-5v-encoder/] | 132.8mm | 6mm | 12V | 117 | 50.9:1 | 9.2A | 250kg-cm | 356 | $31.99 | ball-bearing output shaft
| [ServoCity 165 RPM HD Premium Planetary Gear Motor w/Encoder|https://www.servocity.com/165-rpm-hd-premium-planetary-gear-motor-w-encoder/] | 106.8mm | 6mm | 12V | 165 | 51:1 | 20A | 49kgf-cm | 2443 | $47.99 | 32mm diameter motor, likely larger than necessary
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At line 45 removed 2 lines
This page (revision-54) was last changed on 2021-10-02 05:56 by Murray AltheimTop