Pitching control device for electric vehicle

Abstract

In order to suppress postural changes due to pitching movement occurring when a vehicle is braking, the disclosed pitching control device for an electric vehicle and can prevent deceleration discontinuity occurring at the moment when a vehicle stops by means of appropriate control of the vehicle braking force, can effectively control the pitching movement of the vehicle, and can increase stability and controllability and maintain riding comfort for passengers, even if there are substantial changes in travelling resistance due to road surface gradient, or substantial changes in vehicle weight due to an increase or decrease in drivers or load. The disclosed pitching control device for an electric vehicle implements control which suppresses postural changes in the electric vehicle which are generated by the pitching movements of said electric vehicle. When the electric vehicle is stopped, control is carried out such that a braking / driving torque command value outputted to a drive motor for driving the electric vehicle, is a torque which corresponds to travelling resistance, said torque being a value resulting from the power required to maintain a state wherein the electric vehicle is stopped on a road surface having gradient, being converted into the driving motor torque.

Description

technical field [0001] The present invention relates to a vehicle control device for an electric vehicle, and more particularly, to a technique for suppressing pitching motion of a vehicle. Background technique [0002] The dynamics of the vehicle's attitude are determined by the suspension telescoping of the front and rear wheels, known as the pitching motion. [0003] It is known that the dynamics of the vehicle posture caused by the pitching motion changes according to the running state and the state of the road surface. [0004] For example, when the vehicle accelerates and decelerates, the front-rear direction of the vehicle body generates a moment around the center of gravity, called a pitch moment, in a vertically changing orientation. [0005] A pitching motion is caused by this pitching moment. [0006] In particular, when the vehicle is stopped by braking, since the braking torque is continuously applied to the vehicle until the vehicle stops, a nose-dive that ca...

AI Technical Summary

Problems solved by technology

[0007] Furthermore, since the deceleration based on this braking torque disappears suddenly as the vehicle stops, there is a problem that the energy stored in the suspension due to nodding is released at the same time, causing nodding vibrations.

[0009] Although the ride comfort and handling stability of the vehicle can be adjusted by setting the springs and shock absorbers of the suspension device, it is very difficult to simultaneously achieve ride comfort and handling stability.

[0010] This is because ride comfort and handling stability are opposite characteristics, and in an actual vehicle, the weight of the vehicle varies greatly due to changes in the load of passengers and cargo, so it is difficult to determine the optimum value under all conditions

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