MaxBrix

I haven't, but I think It is possible. I have hope it will be solved. The holes don't really have to be cut but it might get hot.

This is my brushless M-Motor modification. I have used it in a few models and it hasn't self destructed yet. It is pretty good if you don't mind using an RC radio. I also have some Lego compatible servos so the combination makes it easy to build with Lego and use a good radio.

My sixth and fastest Robot dog. https://youtu.be/MC8_yIHKBOc

One unedited shot Walking up Stairs.

Just a happy accident.

Big Dog 5 gets lateral hip motion for a 30% speed increase. Progress continues. Still only one L-motor, no brains.

Thanks, It seems like the realism is an unexpected outcome of trying to make it work better. Weight is my enemy. I have to find another way. It could eliminate bouncing with a flat footpath but that would require one foot to always be on the ground. Running requires bouncing.

Ankles and Hips. I am working toward Raptor 3.0 by experimenting with a leg that flexes side to side and linkage to control the foot path so that it travels under the center of gravity with as little tipping as possible. The leg has to move forward without colliding with the other foot. The lack of springs at this point makes me sad. 3.0 will need to be larger to make the linkage placement more adjustable. It needs a higher step and grip adjustment also.

The feet are made from wire shelf rubber caps with the tip cut off with blue silicon tubes from a whisk inserted through the hole into an axle connector. I personally don't consider the non-Lego radio/ESC/Battery any different than a Buwizz, Arduino, Sbrick or other 3rd party solution. 350mah 2s 35c battery, 10 amp ESC, Radiolink r6 FG receiver - The total weight is 39.1 grams. That tiny weight helps a lot with getting the feet in the air.

Lego Raptor2' moves like a dinosaur by swinging it's head while walking like a real biped. The head not only balances but pushes back on the torque from one leg pushing on the body which usually causes the model to twist back and forth. The tail swings freely absorbing side to side torque. The tail's harmonics cause a delay that keeps the tail on the high side of the walker. Weight far from the center of gravity acts like a tightrope walkers pole. Steering is controlled by a small change of speed altering the bounce of an imbalanced gate. One leg's stride is maybe 1mm longer. When the motor moves slower the air time is less so the stride becomes effectively lower. The change of speed needed is very small. The wider a biped is the more stable it is with both feet on the ground. the narrower it is the more stable it is with one foot in the air. If the CG is low the model the model is more stable standing. If CG is high it will fall less quickly in an imbalanced position. This the first Robo Raptor.

Boston Dynamics Big Dog 4 (Speed Dog). I am trying out a new leg linkage design that has more stable compliance so it can handle non-smooth surfaces. It is also my fastest Big Dog.

Sorry for that first reply. Although smaller that wasn't the same transmission. You want a smaller 2 speed and smooth switching transmission. I rebuilt it smaller as per your request and made a video. Here you go.

This one is the smallest. The down side is that the low gear is slightly less efficient. The upside is that it acts like a CVT by mixing two gear ratios.

The switching mechanism uses the differential as a synchronizer and low gear. It's simple, small and efficient. The small grey gear was lightly sanded so it could slip on the axle. I think there is a red gear that would not need modification. The spring can be replaced with rubber but would require a different build.

It is Tank steering. All of the legs on one side are linked together. The timing of the legs on a side can be done a few ways that work but there is also many that don't so the legs of a side have to stay in sync. The leg lifting motors are independent. Everything is operated by 4 channels. One motor to drive the left legs, one for the right and a motor to lift each leg. The controller is SBrick. I have it set up with a forward fast button, both sides forward 90%, slow at 60%. Turn forward one side 80% other %40. Full turn One side 80% other -80%. And reverse 2 speeds. It could be operated from any 4 channel controller. Just like a tank + 2 channels for the lifting the legs. I can't seem to be able to upload photos.

This Lego spider has an articulated chassis so it can change it's posture and stabilize it's self. When I started I forgot I was sort of building a climbing truck. I started with the weight in the back. The front had no traction and the back wouldn't lift up. I did get it to work both ways but heavy side front for going up and heavy side back going down was best. The little helper legs on the sides were really tricky to get right. In the video you can see some different adjustments to it and working both directions. The helper legs had to replace the back legs when the back legs are in the air and not get caught on obstacles while climbing. The other challenges are the leg stride angle to changing in relation to the ground In the end this allowed for an efficient walking stride and a good alternate climbing stride with more lift depending on the position of the chassis. Next time - Higher.

This method doesn't just increase torque it puts the torque at the end of the drive train. This reduces friction and stress on the entire drive. Mounting to your frame from the turntable puts the wheel near its original placement. After the gear down the torque is distributed through 2 axles that don't twist increasing the strength more than 4x to the highest torque part of the gear train. No more twisted axles. One trade off is you can't mount steering inside the wheel hub.

Sorry I am bad at documentation. I will at least take some good photos for Eurobricks next time. I do have a very simple spider tutorial video though. It's a good place to start with walkers. Diy Walkers has a lot of info on building walkers. About the battery:

The toes are made from the silicon from a wire wisk. When removed from the wisk you have 2mm silicon tube. Now jam them into a Lego axle coupler. Now find a wire shelf. It needs to have soft plastic end caps on the metal frame. These fit snugly on the coupler. cut the tip so the silicon tubes stick out when you put it on the coupler. I show them up close and talk about it here.

It is difficult for mechanical walkers to go over a surface with bumps or any places for the feet to get caught. They often struggle on unlevel ground. This is my latest attempt to defy these restrictions. 4-Bar Linkage legs, Split Chassis, Dual Crank 2 L-Motors 1- Sbrick 1 3S 850mah LIPO

The gun is as compact and light weight as possible. The leg stride has a very small vertical lift so the model can carry the extra weight of the gun without shaking itself to bits. Slowing it down is not an option.

I used slow mo footage to improve the walking efficiency of my big dog quadruped robot. The video has clips of a few iterations showing progress. I improved the existing design with steering, more speed and better stability. I hope to get stabilization integrated into the leg geometry in the future. 1 L-Motor 1 Geek servo (Lego compatible) 1 Additional for stabilization 1 Radiolink R6FG RX 1 2 Amp ESC Sorry for the non Lego radio. It is really good though.

A taser makes a high voltage low current spark in a smallish battery-powered package.