Belgium
Asked — Edited

Serial Servos Lewansoul / Lobot / Dynamixel

Im researching servo's for my inmoov, and came across the serial servos by dynamixel and the more affordable alternatives by lobot (and?) lewansoul.

First of all Im confused, is lobot a knock-off of lewansoul or are they the same and perhaps a new brand name for lewansoul?

Does anyone have experience with these servos (the bigger, serial ones) ? How do they cope with heavy loads, how is their speed/accuracy, backlash and noise?

And last, but not least, I see the lewansoul servos are supported by a EZB plugin, which is fantastic. But is there also support to read parameters back from the servo, like temperature and position? This could be super useful, allowing you to position your robot by hand and then just record those positions.

Likewise, I assume there is no support for changing the PIDs and changing mode from 270 degree to continuous rotation etc?


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#1  

I am also interested in the lewansoul servo's I want to use them in a quadruped robot and in a talking head robot. the reason is the quadruped robot uses more then 8 servo's and the smart servos can be joined together and only use one port and I want to use Io-tiny. ez-robot supplies a cable to connect these servos to the EZB controller and there is a plugin for the dynamixel and lewansoul servos in the app store, so they will work with EZB. I can't find the cable at any of the ezrobot suppliers in canada and the shipping charges is way to much to purchase from the ez-robot store. I would rather buy a cable then make one. why do they have this cable and it is not available from the suppliers?

PRO
USA
#2  

I'm using EZ dynamixel plug in and there is currently no support for reports back from the servo, ie, position, torque etc. Each of these type serial servos usually have a separate control board that monitors nd sends signal via serial to the servos. Might be a better solution to have support for these control boards and then have the ezb monitor the data via another plugin.

https://www.trossenrobotics.com/store/p/6410-CM-700-Robotis-Servo-Controller.aspx

and this for the lewansoul you can use a board like this also has built in memory for playback of stored animations

http://www.lewansoul.com/product/detail-14.html

Belgium
#3  

Given that the function of these boards is largely the same as the ezb controller, Id rather see these additional functions implemented directly in the plugin one day, so we dont need 2 different controller boards and 2 different software stacks with overlapping functionality. Especially since that functionality could be very useful in ezb software, like making the robot say something if one of its servos is overheating or overloaded, or recording servo positions. Im not even sure how you imagine it would work otherwise. Correct me if Im wrong, but these boards seem to require either PWM signals on the servo inputs or be controlled via (proprietary?) software over USB. Im not sure how EZB could interface with them ?

That said, the videos Ive seen of Alan do showcase the quality of the dynamixel servos, they are fast, seem to have little to no backlash and are especially surprisingly quiet, and noise is one reason Id like to use something else than hobbyking or similar RC servos. Of course, the dynamixels also cost an arm and a leg (I guess thats why Alan doesnt have any:p) . You wouldnt happen to know how the lewansouls compare, have you tried them?

PRO
USA
#4  

I think someone on here got some lewansouls and requested the plug in, so DJ stepped in and created one. Their experience after leaving them on overnight were they were hot and they got very noisy, i think you get what you pay for in that respect.

As for the plug in, absolutely the way to go would be to be have a way to monitor directly in ARC. I'm not sure but maybe its a communication thing..ie the plug in can write out to tell the servo where to go, but any returned info dealing with temp and torque etc must be ignore or unable to be retrieve by the EZB.

Dynamixels are stupidly expensive. And they keep making more so someone is buying them. They did release a new model that is the size of a standard servo and cost 49 USD but I cannot get them to work with the Dynamixel plug in.

Belgium
#5  

There are surprisingly few reviews of the lewansoul servos. and none comparing them to the Dynamixel that I can find. I did read a similar story as what you said on a different forum, someone leaving it on overnight going back and forth with little to no load, and it overheated and failed the next day. Then again, he was feeding it with 8.4V, and he never reported back after replacing the motor (you can replace the motors on these, apparently for 5 euro). Amazon has like 5 reviews and they all seem very happy appart from one person needing instructions and another saying they arent very fast. but being smooth is at least as important than being fast, and they have variable speed, although thats also not (yet?) supported in EZB.

Anyway, Ill just buy a few and try. I wont be able to compare to a dynamixel, but at least I can see how it works and maybe even try to modify the plugin code to read back data.

PRO
USA
#6  

Cool I look forward to what you find out.

Belgium
#7  

Ah, found a thread on those servos here: https://synthiam.com/Community/Questions/10643

Both Nink and DJ lambaste these servos and DJ stated no further development will done on the plugin because the servos arent worth it.

Thats a bummer. And possibly a premature conclusion, if no attempts where made to set parameters like speed and PIDs.