New i-SOBOT Checkup
New i-SOBOT Checkup
by Humanoido
Mon Feb 25, 2008 5:11 am
New i-SOBOT Checkup & Calibration
It's a good idea to check the calibration of your new i-SOBOT by running him through some motions and checking the hand, head, leg, arm and torso positioning. It's easy to look for symmetry. After power on, look to see if the left hand matches the symmetry of the right hand, and the same check for the legs. The head should look straight forward. On my new i-SOBOT, when running through some of the commands, the head was hitting the limit position, and the left arm was hitting the chest. A simple adjustment using the supplied wrench was easily accomplished. The process was actually so simple that it surprised me. This is one very well designed humanoid! The wrench fits perfect, the snug is easily determined, and the reposition goes very smooth. I expect that if someone disregarded this calibration, the servo motors could have some premature wear.
humanoido
It's a good idea to check the calibration of your new i-SOBOT by running him through some motions and checking the hand, head, leg, arm and torso positioning. It's easy to look for symmetry. After power on, look to see if the left hand matches the symmetry of the right hand, and the same check for the legs. The head should look straight forward. On my new i-SOBOT, when running through some of the commands, the head was hitting the limit position, and the left arm was hitting the chest. A simple adjustment using the supplied wrench was easily accomplished. The process was actually so simple that it surprised me. This is one very well designed humanoid! The wrench fits perfect, the snug is easily determined, and the reposition goes very smooth. I expect that if someone disregarded this calibration, the servo motors could have some premature wear.
humanoido
by tom_chang79
Mon Feb 25, 2008 5:05 pm
That was one of the first things I checked when I ran my i-sobot for the first time out of the box. The factory might have set it correctly, but vibration and shock induced during shipping (ever seen how UPS and Postal Service handle packages? You swear it was like a wrestling match 
)
The supplied wrench is a standard run-of-the-mill Allen wrench. Since the screws heads doesn't have that much depth, be careful not to round out the corners of the wrench because of half insertion of the wrench.
I personally use a MIP Thorp 1.5mm wrench, which is quite costly for something like this, but it's something I had in my RC tool box...
Also, be very careful not to over torque these little screws. It doesn't take much to do so, just keep your eye on the clamping portion and don't torque any more then when the clamp is fully clamped or nearly fully clamped.
My i-sobot used to wander towards the left when commaned to walk straight, after a few readjustment, it walks much straighter, and has a more symmetrical left turn and right turn with respect to each other!
)
The supplied wrench is a standard run-of-the-mill Allen wrench. Since the screws heads doesn't have that much depth, be careful not to round out the corners of the wrench because of half insertion of the wrench.
I personally use a MIP Thorp 1.5mm wrench, which is quite costly for something like this, but it's something I had in my RC tool box...
Also, be very careful not to over torque these little screws. It doesn't take much to do so, just keep your eye on the clamping portion and don't torque any more then when the clamp is fully clamped or nearly fully clamped.
My i-sobot used to wander towards the left when commaned to walk straight, after a few readjustment, it walks much straighter, and has a more symmetrical left turn and right turn with respect to each other!
by Humanoido
Tue Feb 26, 2008 3:11 pm
What are the advantages of the MIP Thorp 1.5mm wrench over the supplied one with i-SOBOT? Also, I was not able to see enough change in the clamping mechanism to use it as a guide in determining the amount of torque to use when applying force to the allen screw in the clamp. Is this more of an art than a science?
And what is the best way to calibrate so walking is precise in the forward direction without side stray? Do you use the tic marks, or leg to leg symmetry, or both, or another method? Thanks in advance.
humanoido
And what is the best way to calibrate so walking is precise in the forward direction without side stray? Do you use the tic marks, or leg to leg symmetry, or both, or another method? Thanks in advance.
humanoido
by tom_chang79
Wed Feb 27, 2008 7:59 am
Well, the MIP Thorp series of wrenches are the best wrenches in my opinion. The supplied wrench is your standard steel hex wrench, which in most cases are fine. But what separates good tool (screwdriver, hex or other forms) from an excellent tool are the following criteria:
1) Precision of the dimension. The deviation of the tip size from spec will either make it really hard to insert the tool into the screw head or make it too easy which somewhat contributes to 2):
2) Hardness of the tip. Assuming that the tip is pretty close to the spec of the tool, the hardness comes into the factor for the longevity of the screw head. If the tool tip is too soft, the corners will round out, causing the tool to slip, which in turn causes the pattern, in this case the hex, to "strip." A precision tool tip with hardened tip will increase the longevity of the mating between the tip and the screw head, therefore saving you time and hassle of things stripping. Once the tool rounds out and strip the hex for the first time (the first "click" as I like to call it), the damage of the screw head and the tool tip becomes a cycle. Since the screw head is rounded, it rounds the tool tip further and since the tool tip is rounded, it rounds the screw head's patterns, and then back and forth until you end up with a stripped screw head and a messed up tool tip.
MIP Thorps are VERY PRICEY in my opinion, but they are the best IMO. I've used a full set of these in R/C cars. I've torqued the hell out of them and they seem to still hold its shape. No noticeable rounding of the hex edges after repeated "abusive" use!
Before I bought the Thorps, I used to use the run-of-the-mill "L" hex wrenches and "Bondus" hex drivers. I used to always run through a lot of screws because the heads would get stripped out. Ever since I started to use the MIP Thorps, I've never had to replace the screws because the screw heads' shape held together due to the precision of the Thorp and the hardness never gave way...
The quality of the build often hinges on the quality of the tools you apply to them, assuming you know what you are doing
There are other "hardened" tip screw drivers like from integy and the like, but I've never leaned towards any of the other brands.
The Japanese Industrial Screwdriver is a good example of a great tool that probably equals in quality with the MIP Thorp. I know a lot of Robot builders who use this.
Regarding the centering of the i-sobot's joints. I just follow the tick marks on there. It seems to be close enough to make it walk center. At least it mechanically sets them straight. The deviation from a straight walk after this alignment is probably due to the tolerance of the servos. They are the same servos throughout the left and right legs, but each servo has a tolerance. Some are possibly slightly faster, some possibly outputs more torque. No two servos can be the same, even if they are the same model and lot code... They are darn close, but never exact...
1) Precision of the dimension. The deviation of the tip size from spec will either make it really hard to insert the tool into the screw head or make it too easy which somewhat contributes to 2):
2) Hardness of the tip. Assuming that the tip is pretty close to the spec of the tool, the hardness comes into the factor for the longevity of the screw head. If the tool tip is too soft, the corners will round out, causing the tool to slip, which in turn causes the pattern, in this case the hex, to "strip." A precision tool tip with hardened tip will increase the longevity of the mating between the tip and the screw head, therefore saving you time and hassle of things stripping. Once the tool rounds out and strip the hex for the first time (the first "click" as I like to call it), the damage of the screw head and the tool tip becomes a cycle. Since the screw head is rounded, it rounds the tool tip further and since the tool tip is rounded, it rounds the screw head's patterns, and then back and forth until you end up with a stripped screw head and a messed up tool tip.
MIP Thorps are VERY PRICEY in my opinion, but they are the best IMO. I've used a full set of these in R/C cars. I've torqued the hell out of them and they seem to still hold its shape. No noticeable rounding of the hex edges after repeated "abusive" use!
Before I bought the Thorps, I used to use the run-of-the-mill "L" hex wrenches and "Bondus" hex drivers. I used to always run through a lot of screws because the heads would get stripped out. Ever since I started to use the MIP Thorps, I've never had to replace the screws because the screw heads' shape held together due to the precision of the Thorp and the hardness never gave way...
The quality of the build often hinges on the quality of the tools you apply to them, assuming you know what you are doing
There are other "hardened" tip screw drivers like from integy and the like, but I've never leaned towards any of the other brands.
The Japanese Industrial Screwdriver is a good example of a great tool that probably equals in quality with the MIP Thorp. I know a lot of Robot builders who use this.
Regarding the centering of the i-sobot's joints. I just follow the tick marks on there. It seems to be close enough to make it walk center. At least it mechanically sets them straight. The deviation from a straight walk after this alignment is probably due to the tolerance of the servos. They are the same servos throughout the left and right legs, but each servo has a tolerance. Some are possibly slightly faster, some possibly outputs more torque. No two servos can be the same, even if they are the same model and lot code... They are darn close, but never exact...
by Humanoido
Wed Feb 27, 2008 9:24 am
Great info! I don't recall seeing any Thorp wrenches in China, but that doesn't surprise me as most product stock in China is made in China. However, mail order is a possible option and I see most hobby stores in the USA stock these wrenches. The cost currently averages around $11 each, before shipping. Tower Hobbies is one example found here online:
http://www3.towerhobbies.com/cgi-bin/wt ... XAX94&P=WR
It does appear that the smaller the bolt becomes, so does the head become more shallow. This directly increases the propensity for stripping the metal, and I've had some do exactly that on bots smaller than i-SOBOT, but never any stripping of bolts on i-SOBOT.
humanoido
http://www3.towerhobbies.com/cgi-bin/wt ... XAX94&P=WR
It does appear that the smaller the bolt becomes, so does the head become more shallow. This directly increases the propensity for stripping the metal, and I've had some do exactly that on bots smaller than i-SOBOT, but never any stripping of bolts on i-SOBOT.
humanoido
by tom_chang79
Wed Feb 27, 2008 4:57 pm
I use the really small hexes (forgot the size) for the set screw on the pinion gears for R/C cars. I've torqued the HELL out of these since the set screws are notorious for backing out since the pinion is spinning at a really high rate + vibration, and these wrenches have never rounded off.
We (in the US) have TONS of tools from China as well, they are just pure junk, avoid them for precision work. I usually use the tools from China for dirty work, usually for abusive situations such as scratching something or scraping something, or cutting a gauge of wire that are beyond the wire cutter's capability.
I was looking at a bunch of Stanley-brand of phillip's screw driver. All four sides of the "+" pattern at the tip was different in dimension. They are made in China. Again, tools and metals from China are just junk. You get what you pay for is the old saying...
Robophilo is a good example of you get what you pay for. For a biped with 16 to 18 servos, 150 oz/in torque servos are the bare minimum to do anything interesting IMO. Robophilo pack in wimpy servos so if you ever watch the videos on these things, they "sway" back and forth because the servos are struggling to hold position.
I-Sobot is manufactured in China as well, but designed in Japan. I was a little nervous at first since it is made there in China. But so far so good, and I know that the Japanese are a little more demanding of quality for manufacturing in China then the Americans (we buy basically junk goods).
Again, you get what you pay for...
We (in the US) have TONS of tools from China as well, they are just pure junk, avoid them for precision work. I usually use the tools from China for dirty work, usually for abusive situations such as scratching something or scraping something, or cutting a gauge of wire that are beyond the wire cutter's capability.
I was looking at a bunch of Stanley-brand of phillip's screw driver. All four sides of the "+" pattern at the tip was different in dimension. They are made in China. Again, tools and metals from China are just junk. You get what you pay for is the old saying...
Robophilo is a good example of you get what you pay for. For a biped with 16 to 18 servos, 150 oz/in torque servos are the bare minimum to do anything interesting IMO. Robophilo pack in wimpy servos so if you ever watch the videos on these things, they "sway" back and forth because the servos are struggling to hold position.
I-Sobot is manufactured in China as well, but designed in Japan. I was a little nervous at first since it is made there in China. But so far so good, and I know that the Japanese are a little more demanding of quality for manufacturing in China then the Americans (we buy basically junk goods).
Again, you get what you pay for...
by Humanoido
Sun Mar 09, 2008 4:08 am
As screw heads are 1.5mm for the servo adjustments, I'm still using the supplied wrench, and after making several adjustments - it's still working fine. At the same time, I'm very careful in using this wrench. However, the battery compartment has two Phillips (+) screws. I use either a number 0 or 1. The fit really depends on the style of the screwdriver. Some tips are shaped shallow and some are rather steep. Make sure to match one with a good fit or stripping can result. I use standard Precision screwdriver sets. One set has screwdrivers with both numbers 0 and 1, and the other has a number 1.
humanoido
humanoido
by Humanoido
Sun Mar 09, 2008 8:18 am
You can probably head out to the dollar store. This is where I got the precision set. Since there is no appreciable hard turning on these battery lid screws, and the screws are large enough to have significant head metal content and mass, these screwdrivers are very effective. However, for adjustment with the hex bolts, I'd recommend only the highest quality as previously discussed.
humanoido
humanoido