90° Chebyshev like straight line linkage Tuning
■ How about straight line?
Please drag/ move the blue point D ◇. and see the orange ● trace shape.
y(H) = 3.66
y(Axis) = from 3.66 to 3.69 [when x(Axis)=2, just y=3.66]
error gap=0.03 --- 0.03/3.66 < 0.03/3 = 1%
■ calculation of length
H(4,h), HB=a, B(4-a/√2, h+a/√2), B'(4+a/√2,h-a/√2)
So,
AB=OB' ---- ①
a=4√2/(h-2)
and, when bar a (= upper bar) is horizontal (at middle stride),
(a+2)2 + h2 = AB2 ---- ②
solve ① and ②
h = 4√2 -2 (= 3.656854249), --- true
a = 2 +√2 (= 3.414213562), --- true
X-bar = AB= OB' = √(54-8√2) = √42.6862915 = 6.533474688 --- true