RoboSavvy Forum

General • Recommendation for servo

2018-05-04T11:52:10+01:00

Hi everyone,

I'm looking for a servo that is:
1. As small and as flat as possible (only if possible).
2. One that has attachments that can hit a light switch to turn it off and on (such as the one in https://ak8.picdn.net/shutterstock/videos/30233938/thumb/1.jpg?i10c=img.resize(height:160))

Can you give me any recommendation for one?
Thank you!

Statistics: Posted by nettek — Fri May 04, 2018 11:52 am

General • Re: Alpha 2 coding help

2018-02-21T07:01:29+01:00

thanks

Statistics: Posted by trice001 — Wed Feb 21, 2018 7:01 am

General • array's and random

2017-12-01T13:59:31+01:00

in roboplus :
is it posible to create a array of variables ?
can i generate random real number's ?
if yes how do i do that ?

Statistics: Posted by bluatigro — Fri Dec 01, 2017 1:59 pm

General • Re: Alpha 2 coding help

2017-11-27T00:06:28+01:00

hi i bouth alpha2 also.problem i cant get it connect to there server.it worked several weeks then it stopped.
also on my pc the program doesn work.may i ask how did you connect yours ?

thank you

Statistics: Posted by nomad — Mon Nov 27, 2017 12:06 am

General • Re: Inside NAO

2017-08-11T07:04:12+01:00

I love the design of this robot. Looks very friendly. Any updates on the project?

Statistics: Posted by Noblitt — Fri Aug 11, 2017 7:04 am

General • Alpha 2 coding help

2016-12-09T22:31:34+01:00

So I've started to write my own app for Alpha 2. It's open source and can be found on Github -- > https://github.com/CdRsKuLL/Neuron/tree/master

Below is a little video but I was wondering if anyone has any good API (json) sites for questions? So I ask and he finds the answer or plays music etc... So far I have..

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Any help would be great.

Thanks,

Steve

Statistics: Posted by CdRsKuLL — Fri Dec 09, 2016 10:31 pm

General • Re: Flat small BLDC gymball motors use with robots

2016-09-20T13:19:07+01:00

This showed up last week:

New startup web site Ghost Robotics will launch a quad legged gimbal motor direct driven robot with arduino compatible STM32 opensource software and Raspberry Pi native interface.
I'm speculating that it may come in kit format and maybe they will choose to launch it on kickstarter although it is a bit pricey for a successful campaign. They need to get a good pre-order price for the Chinese motors. They achieved enough power density jumping 0.5m by cleverly tethering 2 motors per leg. That's ~$2k just in motors (the rest is ~$300 wholesale in machining, bearings, battery, electronics etc). The 8 encoder boxs look a bit bulky for magnetic encoder boards. maybe they use expensive optical encoders.. So the price will likely to be North of $4.5k.

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Ghost Robotics, LLC, a developer of legged, direct-drive (gearless) and proprioceptive robotics technologies, has announced the launch of its first direct-drive legged robot platform, the Ghost Minitaur.

Founded by University of Pennsylvania PhD candidates, Avik De and Gavin Kenneally, Ghost Robotics is researching and building legged robots that it believes to be superior to wheeled and tracked autonomous vehicles in many field applications. The company’s underlying research and intellectual property have additional applications in surgery, lab operations, healthcare and advanced gait research. The company launched in October 2015 and is backed by the University of Pennsylvania and PCI Ventures, which incubate Penn’s leading research and innovations.

“We are extremely excited to be launching our first commercial robot platform, Ghost Minitaur,” said Gavin Kenneally, co-founder of Ghost Robotics. “This has been a long journey in the conceptualization and development of the robot, and we see many applications for the platform ahead and underlying technology,” added Avik De, co-founder.

Ghost Minitaur is a medium-sized legged robot highly adept at perceiving tactile sensations. Its high torque motors, motor controllers, and specialized leg design allow it to run and jump over difficult terrain while actively balancing, climb fences, and rapidly reorient from falls. High-speed and high-resolution encoders let the robot see and feel the ground through the motors and adapt quickly.

A key application includes deployment of Ghost Minitaur as an autonomous sensor vehicle for public safety, military, exploration, mining, agricultural and hazardous environment operation. The robot can also be used in advanced gait R&D and can be programmed for a range of gaits (bounding, crabbing, walking, trotting), climbing stairs and fences, and even opening doors.

“The forward thinking vision of both Gavin and Avik is quite impressive,” said Jiren Parikh, Ghost Robotics, CEO. “The market opportunity for legged robots in operating environments where wheeled or tracked robots have limitations is substantial.”

Statistics: Posted by limor — Tue Sep 20, 2016 1:19 pm

General • Re: Flat small BLDC gymball motors use with robots

2016-09-02T12:23:59+01:00

Showing a running cheetah style 4-legged robot that uses BLDC servos can really blow some new life back into hobby robotics.
I wonder if one or two Altron motors can make a leg jump 50cm up in the air with weight inclusive of 2 motors and other parts (this means leaving the ground at around 1.5m/sec).
What are the other parts they used to create those legs ? maybe it can be implemented with parts used in delta 3d printers.

Looks like the servos have great price/performance but people complain of quality issues.

Statistics: Posted by limor — Fri Sep 02, 2016 12:23 pm

General • Re: Flat small BLDC gymball motors use with robots

2016-08-18T12:11:29+01:00

Hi !!

Here another application bldc motors to robotics

GOAT: A Legged Robot with 3D Agility & Virtual Compliance by Simon Kalouche

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here his thesis work, which explains everything in more detail
http://www.ri.cmu.edu/pub_files/2016/8/kaloucheThesis.pdf

and finally Pancake MultiRotor BLDC

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http://alturn-usa.com/products/ABSM-42mm-KV650.htm

can be buyer from
https://www.amazon.es/s/ref=bl_dp_s_web_599385031?ie=UTF8&node=599385031&field-brandtextbin=Alturn+USA

Also they have high torque digital servo motors

ABRS-5314HTG+Full HV - Kondo Size (43 × 32× 32.5 mm)
Stall Torque

Torque At 12V: 53.1kg/cm , 708z/in
Speed At 12V: 0.14sec / 60 deg at no load

Torque At 8.3V: 32.4kg/cm , 466oz/in
Speed At 8.3V: 0.16sec / 60 deg at no load

Torque At 7.4V: 25.1kg/cm , 348oz/in
Speed At 7.4V: 0.18sec / 60 deg at no load

link for complete features:

http://alturn-usa.com/products/PDF/ABRS-5314HTG+HV.pdf
some images inside the servo

can be buyer from
https://www.amazon.es/ABRS-5314HTG-Full-HV-Advance-Brushless/dp/B00JWR5ZTS/ref=sr_1_4?s=toys&ie=UTF8&qid=1471515421&sr=1-4

home products site
http://alturn-usa.com/index-e.htm

regards
nicolas

Statistics: Posted by nicolas gomez — Thu Aug 18, 2016 12:11 pm

General • Re: Flat small BLDC gymball motors use with robots

2016-07-17T16:34:16+01:00

Turns out jumping robots have been developed with these motors

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The motor used was the hobby RC quadcopter motor T-Motors U8

http://ieeexplore.ieee.org/stamp/stamp. ... er=7403902

http://kodlab.tumblr.com/post/139972280 ... e-research

Using a STM32F3 controller and a hobby RC driver they managed to get enough power density to make the robot jump to twice its height.

Maybe now thanks to this knowledge, the hobby community can start exploring small scale "big dog" style robots?

Statistics: Posted by limor — Sun Jul 17, 2016 4:34 pm

General • Re: XYZrobot A1-16 Review

2016-05-06T15:09:06+01:00

We decided to see how this servo compares with ROBOTIS Dynamixel AX-12A and AX-18A.

To do that we secured the 3 servos into a piece of MDF and tried to send the same command to all 3 (not a easy task as the BUS is not the same)

To do this we connected the output ports of the CM-530 to a input pin of the XYZ controller board to trigger the same action.

First we checked the speed on position control and then on wheel mode.

After that we went to test the A1-16 position control method with a payload, for that we used 1050g at 10cm and performed some tests.

Check the video for more details

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As you saw on the video the speed is very similar to a AX-12 on position control mode (turning 180º) but that on wheel mode it's faster.

Regarding position control is almost inexistent, let's start by the test 3 on the video.

Small increments in position with a payload, it seems that the servo is trying to go to the goal position but it does not move, what the hell were the firmware guys thinking about? If you do the same test with a ROBOTIS Dynamixel it will try to go to the goal position and will only fail if the payload is bigger than the specs.

On the test 4 you can see that with the exactly same payload but sending the command to move more it will actually move, this means that the servo is powerful enough for that payload just the firmware is badly designed...

After this tests we tried to check how much payload it will hold without trying to move. Unfortunately the horn is not powerful enough and with about 2.6kg at 10cm the plastic was the weakest part. As you can see on the image below the plastic horn should be a square with a trimmed corner and it's now more like a deformed square that rotates on the metal shaft.

We would like to check what would be the maximum moving and holding torque for this servos but due to this issue we were not able to check it as the horn would rotate on the shaft. We performed those tests on the ROBOTIS Dynamixel AX-12A and AX-18A, check the results on this other forum post

Conclusion, there's some potential on the servos in terms of hardware but the bad position control and the very bad designed horn will make it very hard to use as you will have unexpected results.

Statistics: Posted by nunogato — Fri May 06, 2016 3:09 pm

General • XYZrobot A1-16 Review

2016-03-31T12:00:09+01:00

Hi Everyone,

We just received 4 x A1-16 servos from XYZrobot to check the specs and to compare to what seems that they want to compete against the ROBOTIS Dynamixel AX-12/AX-18.

We only had time to make some photos where you can see how similar this servo is to a AX series from ROBOTIS

We are preparing some tests to see how it compares in terms of speed control, position control, torque and strength of the gears with ROBOTIS servos

For now here are the announced specs and some photos below

Operation voltage : 8 ~ 12 V
Maximum speed : 70 ± 10 rpm
Stall torque : 25.0 kg-cm max
Operation Degree : 330° effective position control and endless turn speed control
Range in software is from 23 to 1001 where 512 is the center position, this gives a resolution of 0.337º
Protocol type : Duplex UART 5V TTL serial communication(8, N, 1)
Communication Speed : 9600, 19200, 57600, 115200(default)
Feedback Information : Position, Temperature, Current, Voltage, etc

To see the complete set of photos visit this Flickr album

Statistics: Posted by nunogato — Thu Mar 31, 2016 12:00 pm

General • Has anyone used the designer to RoboCUP by fishertehnik ?

2015-12-02T11:16:05+01:00

Hello,
interested in the following tasks to prepare for the RoboCUP, found on the site, that constructor ROBO TX Explorer (fishertehnik) used in these competitions, who have the experience, tell me?
Thank you in advance.
Best
Regards Katya.

Statistics: Posted by Katrino4ka — Wed Dec 02, 2015 11:16 am

General • Re: MX 106t dynamixel

2015-11-24T17:29:46+01:00

Thanks a lot!
The model is made for a joint of a 3 DoF manipulator, so the gears and so on will hopefully be included.

Statistics: Posted by Steffen — Tue Nov 24, 2015 5:29 pm

General • Re: MX 106t dynamixel

2015-11-24T11:03:46+01:00

The Dynamixel MX106 sitting on my desk has this motor:
IMG_20151124_095108.jpg

Will you also model teh gearbox and such?
Keep us posted on your development!

Statistics: Posted by vmatos — Tue Nov 24, 2015 11:03 am