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Example Sketch/Code for Climbing a Step

Hi Rongzhong,

Great job with this robot. Your passion and dedication towards this project is incredible indeed.

I have purchased a few of your kits and so far it's worked out great. I also believe you and your team have done a great job with the assembly, coarse/fine-calibration instructions.

Can you please share some sample code as an example for climbing up and down a step? I see it in one of your videos, but the standard instincts and any posted newbilities don't have an example to make the Bittle climb up and down step that's 0.5" in height, for example.

If there there is some basic Arduino code that you can share, that'll really help me get started on writing some code to improve on this behavior.

Any assistance is greatly appreciated.

18 comments

18 Comments

gkrangan

Mar 26, 2021

Hi Gero,

Thanks again for your patience and guidance. After messing with the "leanForward" parameter from (-0.5 to -5.0), I guess I'm half way there.

The test step (book) is about 1cm in height. The obstacleHeight is still at 3cms.

However, unsure if the hind-legs will clear the book by adjusting this parameter alone.

Any suggestions to help get the hind legs to get on top of the book?

Behavior definition:

const char zero[] PROGMEM = {

-22, 0, 0, 1,

0, 21, 1,

0, 0, 0, 0, 0, 0, 0, 0,-51, 39, -6, 55, 90, -9, 22, -12, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-17, 6, -7, 64, 37, 6, 25, -10, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 5, -55, 5, 67, 13, 90, 13, -9, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 23, -54, 22, 43, -1, 90, 0, -17, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 35, -51, 40, -6, -7, 90, -9, 22, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 39, -17, 55, -7, -9, 37, -12, 25, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 7, 5, 64, 5, -13, 13, -10, 13, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-52, 23, 67, 22, 70, -1, -9, 0, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-54, 35, 43, 40, 76, -7, -17, -9, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-33, 39, -6, 55, 41, -9, 22, -12, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-13, 7, -7, 64, 14, -13, 25, -10, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 8, -52, 5, 67, -7, 70, 13, -9, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 27, -54, 22, 51, -22, 76, 0, -37, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 42, -33, 40, -4, -29, 41, -9, 2, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 47, -13, 55, -4, -30, 14, -12, 4, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 7, 8, 64, 8, -13, -7, -10, -7, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-52, 27, 67, 26, 70, -22, -9, -21, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-54, 42, 51, 49, 76, -29, -37, -31, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-33, 47, -4, 69, 41, -30, 2, -34, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-13, 7, -4, 80, 14, -13, 4, -32, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 8, -52, 8, 84, -7, 70, -7, -30, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 27, -54, 26, 51, -22, 76, -21, -37, 4, 0, 0, 0,

};

kinematics_bittle_step

.py

Download PY • 11KB

Thanks,

Ganesh

Gero

Mar 26, 2021

Replying to

You can use this parameter, to increase the rear leg swing height. It will be multiplied with the value of swingHeight.

swingFactorLegs = 5    # Increase swing amplitude for legs

gkrangan

Mar 27, 2021

Replying to

Hi Gero,

That was it. I changed it from the default of "1" to "2" and mission-accomplished.

Thanks for your persistent support.

Regards,

Ganesh

gkrangan

Mar 27, 2021

Replying to

Hi Gero,

That was it!! I changed it from the default of "1" to "2" and mission-accomplished.

const char zero[] PROGMEM = {

-22, 0, 0, 1,

0, 21, 2,

0, 0, 0, 0, 0, 0, 0, 0,-57, 16, -5, 55, 90, 4, 19, -12, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-53, -20, -7, 64, 90, 35, 25, -10, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-23, -60, 5, 67, 45, 90, 13, -9, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, -2, -60, 22, 46, 19, 90, -4, -24, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 11, -57, 40, -5, 7, 90, -9, 19, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 16, -53, 55, -7, 4, 90, -12, 25, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-18, -23, 64, 5, 21, 45, -10, 13, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-65, -2, 67, 22, 90, 19, -9, -4, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-64, 11, 46, 40, 90, 7, -24, -9, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-62, 16, -5, 55, 90, 4, 19, -12, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-51, -18, -7, 64, 77, 21, 25, -10, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-19, -65, 5, 67, 27, 90, 13, -9, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 1, -64, 22, 53, 5, 90, -4, -50, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 14, -62, 40, -5, -7, 90, -9, -5, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 19, -51, 55, -4, -10, 77, -12, -2, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-18, -19, 64, 7, 21, 27, -10, -13, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-65, 1, 67, 26, 90, 5, -9, -27, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-64, 14, 53, 51, 90, -7, -50, -37, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-62, 19, -5, 73, 90, -10, -5, -41, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-51, -18, -4, 86, 77, 21, -2, -38, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0,-19, -65, 7, 90, 27, 90, -13, -37, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 1, -64, 26, 53, 5, 90, -27, -50, 4, 0, 0, 0,

};

The final-code is attached as well.

Thanks for your persistent support.

kinematics_bittle_step

.py

Download PY • 11KB

Regards,

Ganesh

gkrangan

Mar 25, 2021

Hi Gero,

Yes, I placed an obstacle of precisely 3cms in height. It was a book.

However, the front legs are not lifting high enough to clear the book. The hind legs do lift more... but due to the issues with the front, the back does not seem to have a chance.

Can you please tell me how I can fix this?

Will try more stuff this evening after work.

Thanks,

Ganesh

Gero

Mar 25, 2021

Replying to

You have to play a little bit with the balancing rear vs. front. The current gait falls over when lifting the front leg. You could play with the following parameters:

leanForward =  0.0      # Shifting torso in x-direction
stanceFront = 0.0       # Distance of front paws from shoulder in x-direction
stanceBack = 3          # Distance of back paws from hip in negative x-direction

The first one shifts the body in relation to the legs forward and backward. So if it falls over in front, use negative values to move the torso backwards in relation to the paws. You can also play with the stance width by manipulating the stanceFront/stanceBack values.

It's a little bit of trail and error and you will need a few iterations.

gkrangan

Mar 25, 2021

Hi Gero,

Yes, I placed an obstacle of precisely 3cms in height. It was a book.

However, the front legs are not lifting high enough to clear the book. The hind legs do lift more... but due to the issues with the front, the back does not seem to have a chance.

Can you please tell me how I can fix this?

Will try more stuff this evening after work.

Thanks,

Ganesh

gkrangan

Mar 24, 2021

Hi Gero,

So made some progress. The leg behavior has improved so to speak 😀.

I now believe I have a better understanding between a posture, gait and behavior. In this case, I believe we are dealing with a behavior.

So here are the few things I fixed:

(1) The first number in the first line was changed to a -ve number to classify it as a behavior.

(2) The number of columns was incorrect in the python script when it formats the CSV file and I fixed line# 273 to this: f.write("4, 0, 0, 0,") instead of f.write("4, 0,")

(3) I also set the second line to "0, 21, 1," in the array definition below to indicate the start-frame, end-frame and how many times to execute the frames.

(4) Here's the "zero" behavior array definition:

const char zero[] PROGMEM = {

-22, 0, 0, 1,

0, 21, 1,

0, 0, 0, 0, 0, 0, 0, 0, 29, 76, 53, 68, -4, 4, -14, 30, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 44, 65, 52, 73, -11, -19, -12, 39, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 60, 19, 60, 70, -11, -1, -11, 47, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 71, 18, 70, 83, -6, 2, -7, -2, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 75, 29, 71, 53, 1, -4, 9, -14, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 76, 44, 68, 52, 4, -11, 30, -12, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 86, 60, 73, 60, -46, -11, 39, -11, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 22, 71, 70, 70, -26, -6, 47, -7, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 22, 75, 83, 71, -24, 1, -2, 9, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 35, 76, 53, 68, -31, 4, -14, 30, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 57, 86, 52, 73, -39, -46, -12, 39, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 80, 22, 60, 70, -40, -26, -11, 47, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 90, 22, 70, 109, -31, -24, -7, -26, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 90, 35, 71, 69, -19, -31, 9, -43, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 90, 57, 68, 68, -14, -39, 30, -40, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 86, 80, 73, 80, -46, -40, 39, -40, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 22, 90, 70, 94, -26, -31, 47, -34, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 22, 90, 109, 102, -24, -19, -26, -21, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 35, 90, 69, 102, -31, -14, -43, -4, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 57, 86, 68, 99, -39, -46, -40, 11, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 80, 22, 80, 91, -40, -26, -40, 25, 4, 0, 0, 0,

0, 0, 0, 0, 0, 0, 0, 0, 90, 22, 94, 109, -31, -24, -34, -26, 4, 0, 0, 0,

};

(5) Video attached.

(6) It's getting there, but not there yet. The front legs are lifting high enough.

I also changed the obstacle-height by 1cm to 4cms.

Any ideas as to what might still be going on?

Thanks much in advance.

Regards

petoi_bittle_step_progress

.mov

Download MOV • 11.71MB

Gero

Mar 25, 2021

Replying to

It's already a good progress. You have to place an obstacle there, otherwise Bittle just falls over, because he expects one to be there. Makes sense, no?

Just be careful with higher obstacles, because the kinematic model will be at the end of range of motion (because the shoulders and hip joints do not move upwards yet). Then the result can be completely unexpected, because the model produces a movement within this range of motion. You can always check this, by looking at the images created by the script, whether the movement looks fine.

BTW: You can upload a video, via "Add a video" and select "from Computer". So one can look at the video directly from the browser.

My NyBoard

Using different servo motor models, how to calibrate

Different parts needed

Example Sketch/Code for Climbing a Step