Summary of the invention
Based on the problem existing for above-mentioned prior art, the invention provides a kind of control method improving pure electric vehicle driving, can not cause accelerate postpone and under accelerating unable prerequisite, the driving solving existing battery-driven car is bad, has the problem of vibration during anxious step on the accelerator.
For solving the problems of the technologies described above, the invention provides a kind of control method improving pure electric vehicle driving, comprising the following steps:
Obtain drive wheel wheel speed and motor speed;
Speed ratio of main reducer in conjunction with this battery-driven car carries out computing to the described drive wheel wheel speed obtained and motor speed and draws correction torque;
The described correction torque that computing is drawn be added to entire car controller in the torque request signal of motor as new torque request signal to control motor.
Beneficial effect of the present invention is: due to the drive wheel wheel speed of acquisition and motor speed are drawn correction torque in conjunction with the speed ratio of main reducer computing of this battery-driven car, and utilize the correction torque that draws to superpose with the former torque request signal of entire car controller to form new torque request signal and control motor, the accelerating curve that motor is exported is more smooth-going while maintenance higher value, therefore pure electric vehicle is made both to have ensured quick acceleration, effectively inhibit again the vibration of vehicle, this control method is simple, easy realization, effectively improves the traveling comfort that pure electric vehicle is driven.
Detailed description of the invention
Be clearly and completely described the technical scheme in the embodiment of the present invention below, obviously, described embodiment is only the present invention's part embodiment, instead of whole embodiments.Based on embodiments of the invention, those of ordinary skill in the art, not making the every other embodiment obtained under creative work prerequisite, belong to protection scope of the present invention.
Figure 1 shows that a kind of control method improving pure electric vehicle driving that the embodiment of the present invention provides, comprise the following steps:
Step 1, obtains drive wheel wheel speed and motor speed;
Step 2, the speed ratio of main reducer in conjunction with this battery-driven car carries out computing to the described drive wheel wheel speed obtained and motor speed and draws correction torque;
Step 3, the described correction torque that computing is drawn be added to entire car controller in the torque request signal of motor as new torque request signal.
In above-mentioned control method, the speed ratio of main reducer in conjunction with this pure electric vehicle carries out computing to the described drive wheel wheel speed obtained and motor speed and show that revising torque comprises:
The first step, carries out multiplying by the speed ratio of main reducer of described drive wheel wheel speed and this pure electric vehicle and obtains signal S1;
Second step, the described signal S1 described motor speed S2 and the first step obtained carries out subtraction and obtains signal e;
3rd step, carry out pid control computation to described signal e and obtain revising dtc signal u, operational formula is: u (t)=kp [e (t)+1/TI ∫ e (t) dt+TD × de (t)/dt].
In above-mentioned control method, each step of method realizes by arranging driving control module in the entire car controller of this pure electric vehicle.
In above-mentioned control method, driving control module comprises:
Motor speed obtains submodule, and it obtains motor speed, is electrically connected through arithmetic and logic unit and PID controller;
Drive wheel wheel speed obtains submodule, and it obtains drive wheel wheel speed, receives submodule, described arithmetic and logic unit and described PID controller be electrically connected through speed ratio of main reducer;
Described arithmetic and logic unit, signal S1 is obtained for the speed ratio of main reducer of described drive wheel wheel speed and this pure electric vehicle is carried out multiplying, and the described signal S1 described motor speed S2 and the first step to be obtained carries out subtraction and obtains signal e, and signal e is sent to described PID controller;
Described PID controller, obtains revising dtc signal u for carrying out pid control computation by operational formula u (t)=kp [e (t)+1/TI ∫ e (t) dt+TD × de (t)/dt].
In above-mentioned control method, driving control module also comprises: wheel speed sensors, obtains submodule be electrically connected with described motor speed, gathers drive wheel wheel speed.For the situation not having abs controller to obtain drive wheel wheel speed, wheel speed sensors can be increased to obtain drive wheel wheel speed, apply the system architecture of the pure electric vehicle of this control method as indicated with 6.
In above-mentioned control method, drive wheel wheel speed obtains submodule and obtains drive wheel wheel speed by the entire car controller of this pure electric vehicle from abs controller.
Below in conjunction with the drawings and specific embodiments, control method of the present invention is described further.
Apply the system architecture of the pure electric vehicle of control method of the present invention as indicated with 2, motor is connected with main reduction gear by axle drive shaft, and main reduction gear drives wheel by semiaxis.Entire car controller is responsible for gathering driver's operation information, as Das Gaspedal information, brake pedal information etc., and the operation of chaufeur is converted into the torque requests to motor, the torque command request that electric machine controller is responsible for receiving entire car controller controls the torque that motor makes motor generation target, and the wheel speed signal of abs controller collection vehicle as antiblock device, and control wheel when braking and do not skid.Entire car controller, electric machine controller are connected by CAN with abs controller.
Control method of the present invention, can on the basis of entire car controller, and increase each step that driving control module realizes controlling, as shown in Figure 3,4, wherein motor speed comes from the CAN signal of electric machine controller to driving control module; Drive wheel wheel speed comes from the CAN signal of abs controller; And the output of driving control module is for revising torque, the correction torque that this driving control module calculates is added to the torque requests of real electrical machinery being formed new torque requests, and then controls motor.
Wherein the computing of driving control module draws the calculation procedure revising torque following (shown in composition graphs 4):
Drive wheel wheel speed is multiplied by speed ratio of main reducer and is the input e (t) of difference as PID controller again with motor speed, after PID controller, export correction torque be designated as u (t), wherein, PID (ratio (proportion), integration (integration), differential (differentiation)) controller is easily understood, and does not need the condition precedenies such as accurate system model in using.
PID controller is made up of proportional unit (P), integral unit (I) and differentiation element (D).Its input e (t) with the pass exporting u (t) is:
In u (t)=kp [e (t)+1/TI ∫ e (t) dt+TD × de (t)/dt] formula, the bound of integration is 0 and t respectively;
Therefore its transfer function is: G (s)=U (s)/E (s)=kp [1+1/ (TI × s)+TD × s];
Wherein kp is proportionality coefficient; TI is the integration time constant; TD is derivative time constant, and these three control variable are demarcated by real vehicle and obtained.
Realizing control method of the present invention by increasing driving control module in entire car controller, pure electric vehicle can be made when anxious step on the accelerator, obtain good accelerating ability and high traveling comfort simultaneously, effectively reduce the vibration that acceleration shock causes.Fig. 5 is in anxious step on the accelerator situation, do not adopt control method of the present invention and adopt the accelerating curve of driving control method of the present invention to contrast, as can be seen from accelerating curve, have employed the accelerating curve of control method of the present invention when keeping higher value, more level and smooth, thus decrease the impact because sudden change of acceleration is formed.
The above; be only the present invention's preferably detailed description of the invention, but protection scope of the present invention is not limited thereto, is anyly familiar with those skilled in the art in the technical scope that the present invention discloses; the change that can expect easily or replacement, all should be encompassed within protection scope of the present invention.Therefore, protection scope of the present invention should be as the criterion with the protection domain of claims.