RoboSavvy Forum

Rook's Pawn III

2008-01-10T18:28:02+01:00

Hey Matt, I noticed that you've got an interesting looking blue slider on its chest. It seems to me that it monitors power consumption, but I might be wrong. What is it?

The blue light is from the illuminated "Rook's Pawn" marquee. The slider is actually an inexpensive multi-colored voltage indicator. It's a "GWS Onboard LED Voltage Monitor" and can be purchased at most hobby shops for around $12-$15. I have mine connected to a switch so I have the option of turning it off while the bot is still on... you don't want your opponents knowing when your batteries are running low

Statistics: Posted by bauermech — Thu Jan 10, 2008 6:28 pm

Rook's Pawn III

2007-11-12T16:44:14+01:00

Hey Matt, I noticed that you've got an interesting looking blue slider on its chest. It seems to me that it monitors power consumption, but I might be wrong. What is it?

Statistics: Posted by bbrainmonkey — Mon Nov 12, 2007 4:44 pm

Rook's Pawn III

2007-08-25T04:57:11+01:00

Any new videos coming soon I hope? Pretty soon he is going to be as tall as you..lol Best wishes at the next robogames we are all cheering for you.

P.S.
Thanks for posting the
info on the 5990's . Very
good to know.

Statistics: Posted by Droid Works — Sat Aug 25, 2007 4:57 am

Rook's Pawn III

2007-08-07T13:25:33+01:00

An impressive Rook's Pawn video showing gyro stabilization
(courtesy of Robots-Dreams.com)

phpBB [media]

Statistics: Posted by limor — Tue Aug 07, 2007 1:25 pm

Rook's Pawn III

2007-07-20T19:30:26+01:00

You'll have to catch them first

Because I bet they'll be running quite fast soon.
He definately leave's me standing

Statistics: Posted by NovaOne — Fri Jul 20, 2007 7:30 pm

Rook's Pawn III

2007-07-20T10:52:57+01:00

That robot is awesome!!!

I'd just like to walk behind Matt Bauer and pick up all his old robots!

humanoido

Statistics: Posted by Humanoido — Fri Jul 20, 2007 10:52 am

Rook's Pawn III

2007-06-20T16:10:17+01:00

Thanks StuartL

but the robot as a whole whistles at an uncomfortable frequency when it's stood/straining. When Matt was doing extended testing my ears felt like they were being drilled from the inside with the tiniest drill conceivable.

Yeah, that pitch did kind of get to me too - after an hour or so of powering him up. By the end of the day, I'm sure the others around me were thinking "Oh man, he's got that thing on again!" BUT, all sixteen of the 5990's powered on, probably outputs the same db's as one or maybe two of the 5995's. ...not too bad I guess.

You lie! You carried on programming all the way to the end of RoboGames!

Nuts! Busted! ...It actually never ends.

Likewise, it was indeed a pleasure meeting you too. Thanks for the programming tips as well

Statistics: Posted by bauermech — Wed Jun 20, 2007 4:10 pm

Rook's Pawn III

2007-06-18T05:34:37+01:00

Having now seen this robot in person this weekend at the RoboGames I can confirm it's a monster. It's a superb piece of engineering and Matt's work on the PC side of software is easily as good as the hardware and software on the robot.

bauermech wrote:
They're quieter as well. The 5995's screamed like wild banshees. These are not that much more audible over the 8498's.

I can't comment on the 8498s but the robot as a whole whistles at an uncomfortable frequency when it's stood/straining. When Matt was doing extended testing my ears felt like they were being drilled from the inside with the tiniest drill conceivable. When in motion the servo noise drowns out the whistle but the servos are still surprisingly quiet considering the load they're under.

Still using the MR-C3024. Programming away... won't stop until RoboGames starts.

You lie! You carried on programming all the way to the end of RoboGames!

It was a pleasure to meet you and a pleasure to see Rook's Pawn in person. I only wish my stuff had arrived in time to give you something else to beat up!

Statistics: Posted by StuartL — Mon Jun 18, 2007 5:34 am

Rook's Pawn III

2007-06-13T21:05:38+01:00

The 5990 only came available last month.

Lynxmotion have them I think ( 124..99 USD !)

Statistics: Posted by i-Bot — Wed Jun 13, 2007 9:05 pm

Rook's Pawn III

2007-06-13T19:47:07+01:00

Thank for the info i-bot.

I checked the 5990TG at servo city and it is NOT listed on the site.
I also checked at my local hobby store, they never heard of it.

Do you know where I can get it. I prefer to order from canada.
If not canada then USA is fine.

Statistics: Posted by AI-Bot — Wed Jun 13, 2007 7:47 pm

Rook's Pawn III

2007-06-13T17:59:48+01:00

The HSR-5990TG has HMI, the HSR-5995TG does not, so avoid it. The 5990 seems more quiet than the 5995, though both are significantly more noisy than most servos. The 5990 also has motor overload protection and better heatsink.

The 5990 has a metallic ring to its sound, like large coins in a bucket, which is rather appropriate !

Statistics: Posted by i-Bot — Wed Jun 13, 2007 5:59 pm

Rook's Pawn III

2007-06-13T17:01:31+01:00

HI

This is probably has nothing to do with anything.
But I notice that Rook Pawn 3 uses Hitec 5990 servo

I have a quick questions.
Hitec 5590 servo and Hitec HS-5995TG - DIGITAL

I know that the speed is 0.12 for 60degree
and their torque is very good.

But how is the noise on them... are they noisy like any other servo.
They are very expensive, just curious before I buy them.

p.s. Nice looking robot.

Statistics: Posted by AI-Bot — Wed Jun 13, 2007 5:01 pm

Rook's Pawn III

2007-06-05T15:45:31+01:00

The on to off ratio of the motor current from 0 to 100% on, is represented in the HMI serial interface as a value from 0 to 255. When you read the servo voltage and current, this value is what is returned.

The servo works internally in microsec from 550 to 2450 for the position which is the servo pulse width, and corresponds to the 10 to 190 value which is sent and read by the HMI pulse modes.

The 8498 default settings have a dead band of +/- 5 microsec, then the motor pwm current rises linearly over the next 100 microsec to 100% in each direction. These settings all appear the same on the 8498 , though they vary on the 5990, and are programmable on both. Note this is the static proportional behaviour, there is also a derivative term, but that does not matter when servo is not moving which is the case we normally want to consider for load sensing.

If the servo is to apply any torque, current must be applied to the motor. Torque is proportional to current when the motor is not moving and no back emf. The current is pretty much proportional to the on to off ratio in the lower current part, guess there are some inductive effects in the motor

If the servo is 30 microseconds off position ( 3 degrees) , it is loaded to about 30%.

Of course with serial HMI you have accuracy 10 times greater than over pulse HMI, and more accurate communication. However measuring the position is still a good way to measure the torque. Also reading the position via serial HMI does not turn the servo off, like the pulse HMI position read.

Statistics: Posted by i-Bot — Tue Jun 05, 2007 3:45 pm

Rook's Pawn III

2007-06-05T13:39:06+01:00

I think the second sentence is more telling:

"This in turn is proportional to the distance of actual position from desired position when not moving."

If the sensed position is different from the desired position, and the servo isn't moving, then it must be applying torque, and the torque is going to be proportional to the amount of power being applied by the motor.

- Jon

Statistics: Posted by JonHylands — Tue Jun 05, 2007 1:39 pm

Rook's Pawn III

2007-06-05T11:31:04+01:00

i-Bot wrote:
The Hitec servos do not measure current directly. The current they report over serial HMI is the proportion of PWM applied to the motor. This in turn is proportional to the distance of actual position from desired position when not moving. If the servos switch off they have to be repowered to reset.

This sounds like important piece of information but i have a hard time following it. Can you kindly expand on this. what do you mean by "proportion of PWM applied to the motor"? why is it proportional to distance? how does externally applied torque, which creates more current consumption, influence the position..

Statistics: Posted by limor — Tue Jun 05, 2007 11:31 am