Why is it difficult to go back in the car as you want?

ByChris Keating

Accidents that accidentally hit the back of a car against a pillar or fence can happen on a daily basis as it is impossible to run the car as expected in backing when placing the car in a parking lot. About reasons why back driving does not go to the desired point, we have published many commentary movies of physics for about 3 minutesMinutePhysicsI am clarifying.

Why is it Harder to Drive Backwards? - YouTube


When you steer the handle while driving with a car, the mechanism that the car bends and runs according to the cut condition of the steering wheel is self explanatory if you have driven a car.


When you turn the steering wheel, the car runs while curving at the same angle regardless of forward or reverse. In this theory it seems that it is not difficult to drive back while cutting the steering wheel, but in reality it is totally different.


The reason why back driving is difficult is that "only the front tire moves by handling the handle". The direction the driver faces does not have much to do with it.


When the car moves forward, the car bends according to the direction of the front tire.


On the other hand, the car will back in the same direction as the rear tire when going in reverse.


However, the crucial difference between the two is that when the car moves forward, the direction of travel is determined by the angle of the front tire, so you can change the orientation of the front tire freely by cutting the handle.


The angle of the rear tire is decided naturally by matching the angle to the front tire.


Such a state is called "stable" in physics. For example, if you grab the tip of a pencil with your fingers and move your hand with the pencil's axis hanging downward, the phenomenon that the tip of the opposite side of the pencil comes about naturally and hand movement can also be called "stable" I will.


On the other hand, when you run the car backwards, the direction of travel is determined by the angle of the rear tire. However, even if the steering wheel is turned off, only the front tire moves.


In other words, you have to decide the angle of the front tire so that the rear tire goes forward at the angle you want to back and you have to handle the steering wheel.


This state is called "unstable" in the field of physics, for example, it is similar to the movement which keeps ono in the palm and keeps the vertical state. In order to stand ono in the palm of your hand, it is very difficult to constantly feed back the movement of the hand while catching the movement of Ono with eyes.


In the same way when driving backward while driving, you need to concentrate on car movement and steering wheel operation.


The forklift which is active in warehouses and others is solving the problem that "the operation of the steering wheel and the movement of the tire are different when backing".


Since the forklift tends to travel backward in the warehouse, the handle and the rear tire are designed to correspond. Also, since the movement of the car body is also slow, it is easier to control the car.


Also, if you run a trailer behind the car, what about the movement of the car as you go back? As the three types of front tire, rear tire, trailer tire move at different angles, "Trailer's tire The rear tire decides the movement and the front tire decides the movement of the rear tire ", furthermore the difficulty of back running increases.


The more trailers you add, the more skilled you need to handle the steering wheel.


MinutePhysics says "Compared to the driving of a truck towing a trailer, it seems easier for ordinary cars to travel backwards"Automobile that parks in a parking lot without automatic drivingIf such an automatic driving car like that for the market appears, it will be released from such troubles.