Parallel Leg Mechanism Design Discussion

Discussions regarding building a walking robot at home. Most of the robots participating at Robo-One competitions are custom fabricated.
39 postsPage 2 of 31, 2, 3
39 postsPage 2 of 31, 2, 3

Post by xanhast » Wed Jun 23, 2010 1:26 pm

Post by xanhast
Wed Jun 23, 2010 1:26 pm

The Vstone Robovie-PC (or KumoTek KT-X PC) uses this or something similar

Google Translate wrote:The knee was heavily "gear interlock parallel link mechanism" adopted


ImageImage
The Vstone Robovie-PC (or KumoTek KT-X PC) uses this or something similar

Google Translate wrote:The knee was heavily "gear interlock parallel link mechanism" adopted


ImageImage
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Post by billyzelsnack » Wed Jun 23, 2010 2:07 pm

Post by billyzelsnack
Wed Jun 23, 2010 2:07 pm

I saw that interlock design awhile back, but didn't study it. That's a pretty interesting way to get rid of a leg servo.

Another thing I like about the Robovie-PC are the shoulder servos which allow for a lot more room inside the torso.
I saw that interlock design awhile back, but didn't study it. That's a pretty interesting way to get rid of a leg servo.

Another thing I like about the Robovie-PC are the shoulder servos which allow for a lot more room inside the torso.
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Post by billyzelsnack » Wed Jun 23, 2010 2:17 pm

Post by billyzelsnack
Wed Jun 23, 2010 2:17 pm

Actually.. Looking at it more it looks like it has conventional hip and ankle pitch combined with the parallel leg setup. Very cool.
Actually.. Looking at it more it looks like it has conventional hip and ankle pitch combined with the parallel leg setup. Very cool.
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Post by Tyberius » Fri Jul 02, 2010 10:17 pm

Post by Tyberius
Fri Jul 02, 2010 10:17 pm

Finally finished up my redesign of Giger.

I've put in a LOT of Inventor time recently. This is a ground up complete redesign from my previous revision, not a single part aside from some bearings and the servos will be re-used. So, I took this as a good time to get the entire robot's frame anodized black.

Here is my finalized model of Giger 4.0, using 14 EX-106+ and 10 RX-64. Stands about 75cm tall.

Image

Giger 1.0 vs Giger 4.0:

Image
Finally finished up my redesign of Giger.

I've put in a LOT of Inventor time recently. This is a ground up complete redesign from my previous revision, not a single part aside from some bearings and the servos will be re-used. So, I took this as a good time to get the entire robot's frame anodized black.

Here is my finalized model of Giger 4.0, using 14 EX-106+ and 10 RX-64. Stands about 75cm tall.

Image

Giger 1.0 vs Giger 4.0:

Image
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Post by mog123 » Sun Jul 04, 2010 2:31 am

Post by mog123
Sun Jul 04, 2010 2:31 am

I won't believe you if you'll tell me you're using the same servos as in the first Giger ;)
I won't believe you if you'll tell me you're using the same servos as in the first Giger ;)
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Post by Tyberius » Sun Jul 04, 2010 3:58 pm

Post by Tyberius
Sun Jul 04, 2010 3:58 pm

Ha, not entirely. Started off with 64s in the legs and 28s in the arms. v2 had the weight bearing 64s in the legs replaced with 106+. v4 is adding an additional set of Ex-106 in the leg-pitch for PLM, and pan/tilt in the waist. The rx-28s in the arm are being replaced by 64s
Ha, not entirely. Started off with 64s in the legs and 28s in the arms. v2 had the weight bearing 64s in the legs replaced with 106+. v4 is adding an additional set of Ex-106 in the leg-pitch for PLM, and pan/tilt in the waist. The rx-28s in the arm are being replaced by 64s
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Post by mog123 » Wed Jul 07, 2010 2:25 am

Post by mog123
Wed Jul 07, 2010 2:25 am

are you telling me your robot costs a couple of k GBP?
are you telling me your robot costs a couple of k GBP?
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Post by Tyberius » Wed Jul 07, 2010 5:20 am

Post by Tyberius
Wed Jul 07, 2010 5:20 am

14 EX-106+ and 10 RX-64 + all the frame components and onboard controller, it certainly adds up quick. :) I do work for Trossen Robotics though, so I get a bit of a discount.

Finished up head design, 80.5cm tall including the head.

Image
14 EX-106+ and 10 RX-64 + all the frame components and onboard controller, it certainly adds up quick. :) I do work for Trossen Robotics though, so I get a bit of a discount.

Finished up head design, 80.5cm tall including the head.

Image
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Post by Stephane » Thu Jul 08, 2010 8:59 pm

Post by Stephane
Thu Jul 08, 2010 8:59 pm

I never feel very comfortable when I don't have both end of a servo axis attached to the other section (such as servos for neck, waist, hips, shoulders and elbow twisting in Tyberius design).
On the other hand, changing these joints is not something so easy.

With a big robot like yours, don't you worry that the load on such attached servo will wear them out faster?

(I am probably worrying for nothing, but I can't help thinking that I must find another way to do when I have this kind of joints, not very successfully so far.)
I never feel very comfortable when I don't have both end of a servo axis attached to the other section (such as servos for neck, waist, hips, shoulders and elbow twisting in Tyberius design).
On the other hand, changing these joints is not something so easy.

With a big robot like yours, don't you worry that the load on such attached servo will wear them out faster?

(I am probably worrying for nothing, but I can't help thinking that I must find another way to do when I have this kind of joints, not very successfully so far.)
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Post by mog123 » Thu Jul 08, 2010 10:26 pm

Post by mog123
Thu Jul 08, 2010 10:26 pm

Tyberius wrote:14 EX-106+ and 10 RX-64 + all the frame components and onboard controller, it certainly adds up quick. :) I do work for Trossen Robotics though, so I get a bit of a discount.

Finished up head design, 80.5cm tall including the head.


I envy you so much. I'd like to work in a company like that. I'm currently designing a humanoid under 400$ (http://xmog123x.blogspot.com/2010/06/im ... alive.html)
Tyberius wrote:14 EX-106+ and 10 RX-64 + all the frame components and onboard controller, it certainly adds up quick. :) I do work for Trossen Robotics though, so I get a bit of a discount.

Finished up head design, 80.5cm tall including the head.


I envy you so much. I'd like to work in a company like that. I'm currently designing a humanoid under 400$ (http://xmog123x.blogspot.com/2010/06/im ... alive.html)
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Post by Tyberius » Thu Jul 08, 2010 10:36 pm

Post by Tyberius
Thu Jul 08, 2010 10:36 pm

Stephane wrote:I never feel very comfortable when I don't have both end of a servo axis attached to the other section (such as servos for neck, waist, hips, shoulders and elbow twisting in Tyberius design).
On the other hand, changing these joints is not something so easy.

With a big robot like yours, don't you worry that the load on such attached servo will wear them out faster?

(I am probably worrying for nothing, but I can't help thinking that I must find another way to do when I have this kind of joints, not very successfully so far.)


These particular joints are reinforced using a different type of horn and a thrust bearing beneath. The current build of Giger was at one point, 7.2kg in weight and about 2/3 the proposed size. It did not stress these joints in any considerable way. The Kung Fu variant that I competed with in Korea at KRGF was lightened up a good amount to just over 5kg, but was under quite a bit more 'wear' given the type of shuffle gaits and impacts I was taking in competition. This again didn't prove to be an issue for these joints. I think as long as they're placed in a manner that they don't have a vertical side loading force on them, it's fine.
Stephane wrote:I never feel very comfortable when I don't have both end of a servo axis attached to the other section (such as servos for neck, waist, hips, shoulders and elbow twisting in Tyberius design).
On the other hand, changing these joints is not something so easy.

With a big robot like yours, don't you worry that the load on such attached servo will wear them out faster?

(I am probably worrying for nothing, but I can't help thinking that I must find another way to do when I have this kind of joints, not very successfully so far.)


These particular joints are reinforced using a different type of horn and a thrust bearing beneath. The current build of Giger was at one point, 7.2kg in weight and about 2/3 the proposed size. It did not stress these joints in any considerable way. The Kung Fu variant that I competed with in Korea at KRGF was lightened up a good amount to just over 5kg, but was under quite a bit more 'wear' given the type of shuffle gaits and impacts I was taking in competition. This again didn't prove to be an issue for these joints. I think as long as they're placed in a manner that they don't have a vertical side loading force on them, it's fine.
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Post by Ausrobo » Fri Oct 01, 2010 9:47 am

Post by Ausrobo
Fri Oct 01, 2010 9:47 am

Tyberius,

I have been following this forum for some time and your design for parallel legs using dual servos has inspired me to come up with my own. I have been working with a Kondo KHR-3HV for some time and would like to continue to use that platform, however need to translate everything from Japanese is just a little tiresome. The Robotis platform looks pretty good.

My goal is to build a biped at around 80cm. I am thinking of legs of about 60cm. The design I have come up with is based on using carbon fibre tubes for the vertical elements in the legs and the servos, top and bottom for the mounting. Unfortunately my cad skill are not up your level and the plans are on paper.

I did have on question. I have been looking at the ankle and hip joints and am concerned that like the legs, they will need two servos each. Have you considered this on your design.
Also how is the design going, have you moved on to construction?
Peter
Tyberius,

I have been following this forum for some time and your design for parallel legs using dual servos has inspired me to come up with my own. I have been working with a Kondo KHR-3HV for some time and would like to continue to use that platform, however need to translate everything from Japanese is just a little tiresome. The Robotis platform looks pretty good.

My goal is to build a biped at around 80cm. I am thinking of legs of about 60cm. The design I have come up with is based on using carbon fibre tubes for the vertical elements in the legs and the servos, top and bottom for the mounting. Unfortunately my cad skill are not up your level and the plans are on paper.

I did have on question. I have been looking at the ankle and hip joints and am concerned that like the legs, they will need two servos each. Have you considered this on your design.
Also how is the design going, have you moved on to construction?
Peter
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Post by Tyberius » Fri Oct 01, 2010 6:00 pm

Post by Tyberius
Fri Oct 01, 2010 6:00 pm

Ausrobo wrote:Tyberius,

I have been following this forum for some time and your design for parallel legs using dual servos has inspired me to come up with my own. I have been working with a Kondo KHR-3HV for some time and would like to continue to use that platform, however need to translate everything from Japanese is just a little tiresome. The Robotis platform looks pretty good.

My goal is to build a biped at around 80cm. I am thinking of legs of about 60cm. The design I have come up with is based on using carbon fibre tubes for the vertical elements in the legs and the servos, top and bottom for the mounting. Unfortunately my cad skill are not up your level and the plans are on paper.

I did have on question. I have been looking at the ankle and hip joints and am concerned that like the legs, they will need two servos each. Have you considered this on your design.
Also how is the design going, have you moved on to construction?
Peter


Hi Peter,

Would love to see your designs when you get them on a digital medium!

I have actually had the same thoughts about the ankle/hip joints. The way I have it designed currently, I could forgo using the current hip/ankle brackets and replace them with the brackets in the knees. Those brackets could then attach to a double EX-106 assembly quite easily. I had even set aside 4 additional knee brackets in my BOM specifically for this purpose.

My current plan was to try it out with a single EX-106+ in the ankle/hip roll positions, and then move on to the double ex-106+ configuration as needed. I'm fairly certain I will need that configuration to get the desired results however. I'm also looking at getting the size down a bit on my own, under 60cm total height so it's still viable for the kidsize Robocup league.
Ausrobo wrote:Tyberius,

I have been following this forum for some time and your design for parallel legs using dual servos has inspired me to come up with my own. I have been working with a Kondo KHR-3HV for some time and would like to continue to use that platform, however need to translate everything from Japanese is just a little tiresome. The Robotis platform looks pretty good.

My goal is to build a biped at around 80cm. I am thinking of legs of about 60cm. The design I have come up with is based on using carbon fibre tubes for the vertical elements in the legs and the servos, top and bottom for the mounting. Unfortunately my cad skill are not up your level and the plans are on paper.

I did have on question. I have been looking at the ankle and hip joints and am concerned that like the legs, they will need two servos each. Have you considered this on your design.
Also how is the design going, have you moved on to construction?
Peter


Hi Peter,

Would love to see your designs when you get them on a digital medium!

I have actually had the same thoughts about the ankle/hip joints. The way I have it designed currently, I could forgo using the current hip/ankle brackets and replace them with the brackets in the knees. Those brackets could then attach to a double EX-106 assembly quite easily. I had even set aside 4 additional knee brackets in my BOM specifically for this purpose.

My current plan was to try it out with a single EX-106+ in the ankle/hip roll positions, and then move on to the double ex-106+ configuration as needed. I'm fairly certain I will need that configuration to get the desired results however. I'm also looking at getting the size down a bit on my own, under 60cm total height so it's still viable for the kidsize Robocup league.
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Servo Hubs

Post by Ausrobo » Sat Oct 09, 2010 8:13 am

Post by Ausrobo
Sat Oct 09, 2010 8:13 am

Andrew,

I have been working on building the hubs that link the carbon fibre tubes to the servos. I am pleased with the first version, however it took way to long to make. I will need 32 of these, so I need a more streamlined way of producing them. The second version was faster but I am concerned if it will be robust enough. Off to design something in between.

Cheers,

Peter

Image
Image
Andrew,

I have been working on building the hubs that link the carbon fibre tubes to the servos. I am pleased with the first version, however it took way to long to make. I will need 32 of these, so I need a more streamlined way of producing them. The second version was faster but I am concerned if it will be robust enough. Off to design something in between.

Cheers,

Peter

Image
Image
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Post by UncleBob » Sat Oct 09, 2010 5:03 pm

Post by UncleBob
Sat Oct 09, 2010 5:03 pm

Funny. I tought about tube yesterday. Tubes to join the servos together actually.
Funny. I tought about tube yesterday. Tubes to join the servos together actually.
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