侧向力 英文.pptVIP

* The slip angle, alpha from the previous slide is the angle between the velocity vector of the vehicle and the center of the tire. The force produced by the tire due to the slip angle is the lateral force Fy. The lateral force acts at a distance from the center of the tire called the pneumatic trail. The lateral force changes as the slip angle changes, the rate of this change is called the cornering stiffness. * The slip angle is equal to the weight on the tires times the velocity of the vehicle divided by the cornering stiffness times the acceleration of gravity times the radius of the turn. We can note several things from looking at the equations. A larger turning radius will lead to a smaller slip angle. The higher the velocity of the vehicle, the greater the amount of slip. A heavy vehicle traveling at an equal velocity to a light vehicle will have a larger slip angle. Additionally, if a supports more weight on the rear tires than on the front tires, the rear slip angle will be larger than the front slip angle. * Steering angle, delta, is also known as the ackerman angle for ackerman type geometry. Some texts refer to it as phi. At low speeds, the steering angle is the length of the wheelbase divided by the radius of the turn. At high speeds the slip angles must be subtracted from the wheelbase length over the radius of the turn. Ideally, wheels follow a true arc when the vehicle is turning. Slippage occurs, however, causing the wheels to alter the path slightly, and we account for it by including the slip angle in our equation. Now that we have discussed the most basic parameters of a vehicle layout * In some instances, vehicles may have only three wheels. The most common example of a three wheeled vehicle is probably a sprayer like the Terra Gator. The nice thing about three-wheeled vehicles is the simplicity in determining the turn center. All we need is the intersection of two lines. The also makes it easy to find the steer angle, and eli