This question is mainly aimed towards Jim or anyone else involved in decision making at Lynxmotion.
I realize that the humanoid robot is not offered as a kit but more of a suggestion of what you can do with the various pieces fo the servo erector set.
Why aren’t they offered as kits? With so much competition, it would be nice to see how an LM biped compares against “kitted” bipeds such as the Kondos, Robonovas, and even the budget Robophilos.
They have a comprehensive review and comparison of various bipeds and are quite up to date (the inclusion of the i-sobot for example in the comparison).
Would love to see how LM’s bipeds stack up against the rest if it were kitted.
I’m currently working on the biped scout+ssc-32+abb+atom pro 28. Am thinking about migrating to a humanoid biped by purchasing the humanoid chassis and a few more brackets necessary.
What are the parts I would need for this migration? I would obviously need the chassis for starters and a few more servos, but besides that, what do I need?
I think comparing the Lynxmotion bipeds against the Robonovas or the kondos is unfair. The servo brackets on the production bipeds were designed specifically to work with the biped configuration, where as the lynxmotion brackets are universal meaning you can take the same brackets and build something else unlike the robonovas etc…
The Lynx brackets have the ability to bolt together in many configurations so its not surprizing that for this reason, some designs are not the most efficiant design possible. If Jim optimized each bracket to work the most effective, there would be no SES.
The brackes of the Kondo were desinded to give a precise fit and function, therefore, the brackets are not reusable for a new design.
It sounds like you are looking for Out-of-the-box performance, so a ready made biped is a better choice. Many builders like to experiment with new things, so like my self, I chose to build my own using the LM brackets and try different things and configurtions.
The word SES can cause confusion since they are not really a true “set”. I think they should have called them “LMB’s” or something similar.
I am the one who makes the final decision about all things robotic at Lynxmotion. I consider SES based humanoid bipeds a do-it-yourself project. The minute I make a humanoid “kit” I will be asked for the kit with these grippers instead of those or this micro instead of that, or this control scheme or that, and why didn’t you put in a waist rotate? etc. We make the parts to let the people chose how they want their robot to look and work. Lynxmotion is a small family run business. We do an enormous amount of work to make these products available to the robotics community. So there must be trade-offs concerning where we spend our energy. 2008 is the year we close the control loop for our bots. You will see many sensors on feet (finally) for our walking robots. We will add many new tutorials on the BRAT illustrating many different methods of control as well. We are also putting a great deal of time and money into more powerful servo and microcontrollers, and an assortment of micro and quarter scale servo brackets. I could however spend the majority of my time adding Biped kits, but at what cost to these other developments? We are doing the best we can.
I think like SN96. I prefere to build my own stuff, now comparing the rest of the robots with one we could do with SES parts isn’t fair. Using the same servos you could probably end up (if you’re a good builder) with a design that will do what you want it to do better than the SES could do, but then you would have to build all your own brackets. try to make them as light as possible while it can still hold the biped without bending, now the SES is beefier because it was consieved for durable use and you can use it with anything.
Well said Jim, SN96, and Sam. I appreciate the point of views.
I still consider the LM parts to be the Cadillac for servo-based robots. The brackets are alot beefier and the anodized finish is a plus.
I think I will try to answer my own question of migrating to the humanoid walker by asking myself some questions such as waist rotate, what kind of grippers, and most important, how much is in my bank account
Tom, I hope we didn’t come across as being harsh. There are so many variables when deciding on where to go with a project or what to do. I tend to research my ideas and see what others have done before making a finnal decission. Its best to take the time and really plan out what you want to do. Sometimes you will make an error in your judgement but that’s all about the hobby, not everything is going to be a smooth ride.
No offense taken in any of the posts. So long as the posts are informative and not insulting, I don’t take it as an offense.
I bought an i-sobot as a fun humanoid to mess with, but I’m still continuing to develop the biped scout since it has so much more potential then the i-sobot. Just the ability to swap out servos and the power of the ABB/Atom Pro28 + SSC-32 gives it so many different possibilities.
Initially, I wasn’t attracted to any of the humanoid style, but watching recent videos of kondos and robonovas have somewhat captured my attention towards these types. Not to mention putting less strain on the servos with a humanoid style legs compared to the strain like on biped scout. Still, the biped scout has lower stance so the COG is much lower as compared to the biped humanoid.
I love the ABB+Pro 28 and the SSC-32. That’s what really sold me on using LM’s robot kits.
Since I have the original humanoid robot that Jim made, and have learned how to make it walk. I can tell you from first hand experience that teaching a new robot design how to walk from scratch without any examples to work with is extremely difficult and time consuming.
If Jim were to make this a full product, he would have to develop the controller and software to the point that anyone can use it and run the robot out of the box. This would also be time consuming, and probably very expensive for his company to take on.
I can just imagine all the emails Jim gets for help regarding the Brat and the Scout that doesn’t show up on this list. And I am pretty sure he gets a lot about humanoids. If humanoids were a product, he would be flooded with emails asking for help.
Though I don’t personally have a Brat, I can say it is a realitvely easy robot to get up and running, when compared to the Scout. I can base this on my experience in getting the Lynx 209 to stand, walk, and turn around for the first time a couple years ago. Humanoids are a bit tougher than that.
I think the Lynxmotion SES parts will do well in a Robo-One competition. And since it is flexible, it will do very well in the Eagle event. I would love to do the Eagle event some time.
Thanks for sharing your experience with the lynx 209, Pete. Curious, what servos did you use on the lynx? I’m trying to determine which servos needs to be swapped out for stronger ones.
My goal with my scout is to have a relatively good height clearance on the lifted leg during a walk. Currently, I’m using the HS-645MG for all twelve servos on the scout, and the knee that’s on the planted leg seems to be maxing out on the load. I’m thinking of swapping out the knee servo, and the servo “above” and “below” the knee if you view the servos on the legs as a chain.
I am using the HS-5645 servos. I will never go back to analog servos again. The HS-645 and the HS-5645 servos are identical in all aspects except for the internal circuit board. The internal electronics makes these servos a little bit better than the HS-645.
If you are using the SSC-32, then you are not really going to notice much of a difference between the HS-5645 and the HS-645 sevos since it is a mighty fine servo controller.
If you want to replace any of the servos for a higher torque ones, go with the HSR-5980SG servos. I would recommend that you replace all of the servos.
Right now you are seeing that the knees have a high current draw. You will get this with moving or standing still. But as soon as you replace these servos with better ones, you will then begin to notice that your ankle servos are drawing a lot of power when the body shifts its weight from one foot to another. Then you are going to want to replace those servos.
Then you are going to want to do some kick turns, and the next thing you know, the hib servos are a big current draw. And so on, and so on.
You can replace the servos one at a time, but in the end (assuming that you plan to do some really interesting things with the robot) you will replace all of them. It is best to do this up front to avoid all of the frustrations of having to deal with the weaker servos.
I’m planning on going to a more powerful servos altogether, and buy some more brackets to make mine similar to the waist rotate humanoid biped. Going to probably transfer my “old” hs-645s onto the top portion, basically any non-leg portion of the biped.
Looking at the HSR-5980sg/5990tg versus their hs-5955tgs, are these identical servos? Are the 5980/90s just rated to a higher voltage (7.4v) from testing, or are the internal electronics more tolerant to these conditions: such as the breakdown voltage of various parts of the internal boards having a higher breakdown?
The scout has a lot of potential with a lower COG and all, but looking at some of the robo one videos and robo games videos, I kinda want a humanoid style robot. The waist-rotate humanoid biped that Jim made is a beaut!
I believe taht the 5980/90 are better at supporting the weight for a reasonable amount of time. The board won’t burn out, but I would still use it at only 6 volts I plan on buying some of these beasts soon but
Fast question : the only reason for titanuim gears is that is makes the servos 2 grams lighter.
thanks for that link sam. Not sure if I’m going to be using it at a higher stall torque (biped humanoid’s legs), but I will definitely be on the look out for heating issue of the power fet on the pcb.
Are the “charged” condition of the batteries ever factored in? For a give “1.2V” cell, with 5 in series, it would produce a net voltage of 6.0V theoretically. But, when fully charged, it has an open-circuit voltage of about 7.2V and it only drops slightly depending on the load.
A 7.2V pack gets even worse. I have a 6-cell sub-c packs from my r/c car (3300mAH which is crappy for R/Cs but waaaaay over what you need for a robot with heating servos).
They are 6cell at 1.2V each, so they produce 7.2V theoretically. But when fully charged, the open-circuit voltage is approximately 9 volts. I’ve ran them on my scout that has 12 hs-645mg for a short period of time without blowing the servos. Maybe I got off lucky. But my memory from that is, the servos felts as if it was on steroids and the it heating up after about 3-4 minute use (by then I turned it off). 8)
I guess the difference between the 5980sg/90tg versus the 5955tg counterparts is that the 80sg/90tg has a over-current protection? Or is it a thermal protection, such as having a thermistor inside to sharply cut the current?
Moving the 645 servos to the arms in a humanoid is only delaying the inevatble, that you will need the higher torque servos in the arms also. The arms will see a lot of torque when you start experimenting with the concept of getting back up on its feet. The robot is going to fall over. So how do you get the robot to get back on its feet? The arms. I learned this the hard way.
Hey Pete, thanks for the helpful tip. Are you currently still working on the humanoid biped made from the LM’s SES? I was wondering what kind of servos people are using and what kind of runtime with what kind of battery. Do you have to shut it down due to overheating?
I am using the 6.0 Volt Ni-MH 1600mAh Battery Pack that Lynxmotion sells.
I don’t know how long it lasts, time wise. When I am developing code, I use a bench top power supply. When I go to shows and tournaments, I use the battery pack. Generally one charge gets me through the day. The competition and a bunch of demo’s. But I couldn’t tell you how much actual robot-ON time there was. When I go to tournaments and shows, I bring spares with me just in case I need to change one.
Right now I am using the HS-5645 servos. I haven’t been noticing an overheating problem. If the robot isn’t doing anything, I turn it off. The power is only on during a contest or a demo then I shut it off.
I will evenutally upgrade to the more powerful servos, but that is out of the budget/priority list right now.
I posted some humanoid biped with hip rotation done in solid works. It’s something that’s been lingering in my mind since I saw the torso-rotating biped. The design was also inspired partly by the KHR-series biped humanoid from Kondo.
Originally, I had it drawn with the “shin” servo just a bit forward in relation to the “knee,” which is the scheme that Kondo uses on their bots, but not sure what the advantages are…
I plan on buying some of these beasts soon but