I am looking at this code as my students have found this video for an example to build code based off of this ramp up style of gyro coding. They had a question about the "20" on the set Degrees variable block (2:38) . What does the 20 signify? Size of the tire?
Hi Timothy 20 is the factor you need to convert cm to degrees. I measured the wheel diameter as 5.6 cm, this gives a circumference of 17.59 cm. One wheel rotation is therefore 360 degrees and 17.59 cm. The factor I need is in theory 360 divided by 17.59 which is 20.46. I then programmed the robot to drive 50cm with this factor and measured the distance travelled. I had to slightly modify the factor to give me the correct result. Theory and practice are usually slightly different! The sources of error are perhaps my measurement of the wheel diameter, some wheel slip and some overshoot at the end of the 50cm run which would be speed dependent. Factor 20 gave good results and is a nice round number. I hope this answers your question, thanks for your interest!
Excellence explanation and great video as always. Can you make a video about pros and cons of using distance sensor and touch/force sensor? I don't see people use those sensor much during competition.
Hi, thanks for your comments! It's true, you don't see much use of force sensors in competitions, you could use one to tell when you have reached the side of the table for example. Is this what you have in mind? Have you tried using one yourself?
@@why-not-bot yeah, without the touch/force sensor, you have to measure the distance to reach a object or destination point (because there's no line lead to that object). Is this the technique you usually use in the competition? This requires multiple tries and fine tune, doesn't it?
Hi again I have sometimes used one motor to do two things like lift, grab etc. It is not easy to do more than two things because both operate at the same time and both will have to have about the same number of motor rotations. It is something I have often thought about, if I have any new ideas I will definitely make a video!
Hi there I really appreciate the time you’ve put in making this video, I have one question, in the “S” ramp, when we scale the function, you have a hard-coded value of “8” could you please tell me what this number signifies. Thank you for your help.
Hi There I will do my best to explain the value of 8. We calculate the distance travelled as Adegrees/Degrees. This varies from 0 to 1 over the distance we want to travel. The S-curve equation I have used has an input of minus infinity to plus infinity for an output of zero to one. If we use an input of minus 4 to plus 4 we use about 99% of the curve which is good enough for our ramp. So before we can use the S-ramp curve we have to convert the signal which varies from 0 to 1 into -4 to plus 4. To do this I multiply by 8 and then subtract 4. I hope I have managed to explain it! Best regards Paul
Hi there, thank you for your excellent video. Can you provide me the PDF file you mentioned in 4:29? Thank you!
Hi, send me your email address and I will send the file. My address is pablocutler@gmail.com
I am looking at this code as my students have found this video for an example to build code based off of this ramp up style of gyro coding. They had a question about the "20" on the set Degrees variable block (2:38) . What does the 20 signify? Size of the tire?
Hi Timothy
20 is the factor you need to convert cm to degrees. I measured the wheel diameter as 5.6 cm, this gives a circumference of 17.59 cm. One wheel rotation is therefore 360 degrees and 17.59 cm. The factor I need is in theory 360 divided by 17.59 which is 20.46. I then programmed the robot to drive 50cm with this factor and measured the distance travelled. I had to slightly modify the factor to give me the correct result. Theory and practice are usually slightly different! The sources of error are perhaps my measurement of the wheel diameter, some wheel slip and some overshoot at the end of the 50cm run which would be speed dependent. Factor 20 gave good results and is a nice round number. I hope this answers your question, thanks for your interest!
Excellence explanation and great video as always. Can you make a video about pros and cons of using distance sensor and touch/force sensor? I don't see people use those sensor much during competition.
Hi, thanks for your comments!
It's true, you don't see much use of force sensors in competitions, you could use one to tell when you have reached the side of the table for example. Is this what you have in mind? Have you tried using one yourself?
@@why-not-bot yeah, without the touch/force sensor, you have to measure the distance to reach a object or destination point (because there's no line lead to that object). Is this the technique you usually use in the competition? This requires multiple tries and fine tune, doesn't it?
@@why-not-bot do you have a video about motor simulation? e.g one motor for many actions likes grab, lift ...
Hi again
I have sometimes used one motor to do two things like lift, grab etc. It is not easy to do more than two things because both operate at the same time and both will have to have about the same number of motor rotations. It is something I have often thought about, if I have any new ideas I will definitely make a video!
@@why-not-bot thanks in advance. may I ask if you're located in Australia?
Hi there I really appreciate the time you’ve put in making this video, I have one question, in the “S” ramp, when we scale the function, you have a hard-coded value of “8” could you please tell me what this number signifies.
Thank you for your help.
Hi There
I will do my best to explain the value of 8.
We calculate the distance travelled as Adegrees/Degrees. This varies from 0 to 1 over the distance we want to travel. The S-curve equation I have used has an input of minus infinity to plus infinity for an output of zero to one. If we use an input of minus 4 to plus 4 we use about 99% of the curve which is good enough for our ramp. So before we can use the S-ramp curve we have to convert the signal which varies from 0 to 1 into -4 to plus 4. To do this I multiply by 8 and then subtract 4. I hope I have managed to explain it!
Best regards Paul
@ thank you that does explain it!!!
Hi, you asked if I am located in Australia. I am a long way from there, in Switzerland! How about you?
Very close to me! I live in Germany near the Lake of Constance!
Very close! I am in the Zürich area!
@why-not-bot nice! i live near Friedrichshafen.