US 7,010,412 B1Granted

Method for calculating parameters in road design of S-type clothoid, complex clothoid and egg type clothoid

AssigneeSaman Engineering Consultants Co., Ltd.

InventorGyu-Seok Song

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Abstract

The present invention relates to a method for calculating parameters in a road design of a S type, a complex type and an egg type clothoid, and in particular to a method for calculating a parameter value capable of determining the size of a clothoid that is inserted when designing a S-shaped and interchange, a connection road, etc. in an egg shape. In the present invention, it is possible to easily calculate the clothoid parameter A in a S shape, complex type and egg type road design, and a road design can be fast finished. In addition, in the present invention, it is possible to achieve an easier design of a S shape and egg type clothoid by determining a design specification without using CAD. The design can be achieved based on a simulation using a center coordinate of two circles for achieving an optimum design.

Claims10

Dependent claims

In a method for designing a road, an improvement comprising calculating parameters A1 and A2 in an S-shaped clothoid with R1, R2, D and

A
2
A
1
being known values and R1 and R2 being radii of two circles and A1 and A2 being clothoid parameters A adapted to R1 and R2, respectively, and D being a shortest distance between circumferential portions of two circles, a method for calculating the S-shaped clothoid parameter comprising:
a step in which an initial value of a tangential angle τ1 of the radius R1 is set;
a step in which the tangential angle τ1 is compared with 0, and when a result of the comparison is less than 0, since it means there is no solution, the process is stopped, and when a result of the same is greater than 0, a value of (R1+D+R2)2−XM2 is calculated, XM being a function of an unknown value τ1;
a step in which a value of (R1+D+R2)2−XM 2 is compared with 0, and when a result of the comparison is less than 0, τ1 is properly adjusted, and the routine goes back to the next step of setting the initial value of the tangential angle τ1, and when a result of the same is greater than 0, the function F(τ1) is calculated and the function F′(τ1) which is differentiated with τ1 from the function F(τ1) is calculated;
a step in which a ratio
G
=
F
⁡
(
τ
1
)
F
′
⁡
(
τ
1
)
is calculated;
a step in which τ1=τ1−G is calculated (τ1 is reduced by G);
and
a step in which an absolute value of G is compared with a tolerance of 10−6, and as a result of the comparison when the absolute value of G is greater than the tolerance, the routine is fed back to the next step where the initial value of τ1 is set, and when it is less than the tolerance, the tangential angle τ1 is determined, and A1, which is a clothoid parameter A adapted to R1, is easily calculated using τ1, and A2, which is a clothoid parameter A adapted to R2, is also easily calculated using A1 and given value
A
2
A
1
.

30 more elements

In a method for designing a road, an improvement comprising calculating A in an Egg-shaped clothoid with R1, R2, D being known values and R1 being a radius of a larger circle and R2 being a radius of a smaller circle and D being a shortest distance between circumferential portions of the two circles, a method for calculating an egg-shaped clothoid parameter, comprising:

a step in which an initial value of a tangential angle τ1 of the radius R1 is set;
a step in which the tangential angle τ1 is compared with 0, and when a result of the comparison is less than 0, since it means there is no solution, the process is stopped, and when a result of the same is greater than 0, a value of (R1−R2−D)2−XM2 is calculated, XM2 being a function of an unknown value τ1;
a step in which the value of (R1−R2−D)2−XM2 is compared with 0, and when a result of the comparison is less than 0, τ1 is properly adjusted, and the routine goes back to the next step of setting the initial value of the tangential angle τ1, and when a result of the same is greater than 0, the function F(τ1) is calculated and the function F′(τ1) which is differentiated with τ1 from the function F(τ1) is calculated;
a step in which a ratio
G
=
F
⁡
(
τ
1
)
F
′
⁡
(
τ
1
)
is calculated;
a step in which τ1=τ1−G is calculated (τ1 is reduced by G);
and
a step in which an absolute value of G is compared with a tolerance of 10−6, and as a result of the comparison when the absolute value of G is greater than the tolerance, the routine is fed back to the next step where the initial value of τ1 is set, and when it is less than the tolerance, the tangential angle τ1 is determined, and the value of parameter A is easily calculated using the tangential angle τ1.

20 more elements

Dependencies are inferred from the claim text.