Zeaker2 - critical dimensions ============================= Track ----- Specify - 0.5mm/0.5degree per motor step If track circumference is 360mm then if each motor does 1 step then robot turns 1degree if one motor does 1 step and other motor is stopped then robot turns 1/2 degree circumference=360mm => diameter =360/PI() =114.591559mm circumference=360mm => diameter =360/PI()/25.4 =4.511478702inch so if track is 4.5inch then accuracy is within ~0.2% 4.5*25.4 =114.3mm dia mm PI*dia /360 -1 (=error) % dia inch ~ 114 358.1415625 0.994837674 -0.005162326 -0.516232636 4.488188976 4.49 114.25 358.9269607 0.997019335 -0.002980665 -0.29806648 4.498031496 4.5 114.3 359.0840403 0.997455668 -0.002544332 -0.254433249 4.5 4.5 114.5 359.7123588 0.999200997 -0.000799003 -0.079900323 4.507874016 4.51 114.6 360.0265181 1.000073661 7.36614E-05 0.007366139 4.511811024 4.51 114.7 360.3406774 1.000946326 0.000946326 0.094632602 4.515748031 4.2 114.75 360.497757 1.001382658 0.001382658 0.138265833 4.517716535 4.2 115 361.2831552 1.00356432 0.00356432 0.35643199 4.527559055 4.53 so specify 114.5 +-0.5 =>-0.5% +0.4% or specify 4.51inch +-0.02 =>-0.5% +0.4% or easier to remember 4.5inch +-0.01 =>-0.5% +0.14% DriveBoss --------- 1 step is 0.5mm motors are 48 steps/rev so BossCircumference must be 24mm 24/3.1415926 =7.639437399 ~=7.64 7.65 -0.01 =7.64 7.64/7.64 =1 7.65 +0.01 =7.66 7.66/7.64 =1.001382641 7.65 -0.025=7.625 7.625/7.64 =0.998036649 7.65 +0.025=7.675 7.675/7.64 =1.004581152 7.65 -0.05=7.6 7.6/7.64 =0.994764398 7.65 +0.05=7.7 7.7/7.64 =1.007853403 7.65 -0.1 =7.55 7.55/7.64 =0.988219895 =>~1% 7.65 +0.1 =7.75 7.75/7.64 =1.014397906 =>~1% so make boss 7.65 +- 0.1 mm inches 24/3.1415926/25.4 =0.300765252inch 0.3 -0 0.3/0.300765252 =0.997455651 0.3 +0.0015 0.3015/0.300765252 =1.002442929 7.55 =0.297244094 7.75 =0.30511811 or make boss 0.3 +-0.005 0.295/(24/3.14159/25.4) =0.980830578 0.305/(24/3.14159/25.4) =1.014079072