Ackermann Steering Most vehicle steering systems use some form of the Ackermann Steering model. For turning stability tires will turn on different radii.

Ackermann Steering

Research First step was to research steering geometries and types of mechanism suitable for our requirements. – Cheap – Rugged – Easily maintained – Readily available parts

Mechanism Selection Mechanism should provide moderate responsiveness and ease of operation – Best choice – Recirculating Ball Steering Mechanism

Mechanism Elimination Hydraulic – Failed Ease of Maintenance and availability of parts. Rack and Pinion – Failed ease of operation at low speeds

Rough Geometry Due to the suspension design I was required to follow the following setup.

Geometry

Equations

Left Side Equations

Right Side Equations

Equations VariableDescription aDistance from knuckle to center link bTravel of center link cDistance from center link to axis of rotation xLength of steering knuckle yTie rod length Angles between steering knuckle and tire Angle between knuckle and axis of rotation on the left side Angle between knuckle and axis of rotation on the right side Left turn angle Right turn angle

Program #include int main(){ float y, c, b; double x= 6.403; double P, Q, R, Theta1, Gamma1; double I, J, K, Theta2, Gamma2; printf("Input value for y: "); scanf("%f", &y); printf("Input value for c: "); scanf("%f", &c); printf("Input value for b: "); scanf("%f", &b); printf("The values entered are: %f, %f, %f\n", y, c, b); float a = ; float g = ; float pi = ; printf("a equals: %f\n", a); printf("g equals: %f\n", a); R = pow(y,2) - pow(x,2) - pow(b,2) - pow(a,2) - pow(c,2) - 2*a*b; Q = 2*x*c; P = 2*x*(a+b); K = pow(y,2) - pow(x,2) - pow(b,2) - pow(g,2) - pow(c,2) + 2*g*b; J = 2*x*c; I = 2*x*(g-b);

Program I = 2*x*(g-b); printf("P equals: %f\n", P); printf("Q equals: %f\n", Q); printf("R equals: %f\n", R); printf("I equals: %f\n", I); printf("J equals: %f\n", J); printf("K equals: %f\n", K); double den1, den2; double den3, den4; den1 = sqrt( pow(P,2) + pow(Q,2) ); //denominator den2 = den1; //both denominators are the same den3 = sqrt( pow(I,2) + pow(J,2) ); //denominator den4 = den3; //both denominators are the same Theta1 = ((1 / cos((R/den1)*(-1)) - 1 / cos(P/den2))*(180/pi)); Theta2 = ((1 / cos((K/den3)*(-1)) - 1 / cos(I/den4))*(180/pi)); printf("Theta1 equals: %f\n", Theta1); printf("Theta2 equals: %f\n", Theta2); Gamma1 = ( Theta1); Gamma2 = ( Theta2); printf("Gamma1 equals: %f\n", Gamma1); printf("Gamma2 equals: %f\n", Gamma2); getch (); return 0; }

Sample Input Values cyb

Final Geometry

 Turn Radii ◦ 7.15 ft. (Inside) ◦ ft. (Outside

Parts

Constructed System

Deliverables  Mechanism Selection  Rough Geometry Selection  Geometric Equation Research  C++ Program  Calculations of Ackerman Angles  Final Geometry  Construction

Conclusion  Questions?