CN1760776A

CN1760776A - Drive unit for digital control pointer type meters in cars, and drive method

Info

Publication number: CN1760776A
Application number: CN 200510057359
Authority: CN
Inventors: 程方; 王平; 李银国; 李铮; 邓炳光; 邓定春
Original assignee: Chongqing University of Post and Telecommunications
Current assignee: Chongqing University of Post and Telecommunications
Priority date: 2005-11-03
Filing date: 2005-11-03
Publication date: 2006-04-19
Anticipated expiration: 2025-11-03
Also published as: CN100483274C

Abstract

The invention is related to automotive meters and instruments. PWM modulation method is adopted in the invention to drive step motor of pointer type meters directly. Relevant algorithms solve nonlinear acceleration and retardation in pointer rotation. Thus, software algorithms accomplish functions such as driving and speed controlling etc, which are implemented by hardware drive formerly. The invention reduces cost of instrument, complexity of hardware, and raises generality of system.

Description

The digital control pointer type meters in cars Drive And Its Driving Method

Technical field

The present invention relates to automation field, relate in particular to automobile intelligent instrument and meter drive controlling.

Background technology

Mostly present automobile is to adopt the hardware driving circuit of special use to realize that the micro-stepping of the stepper motor of pointer instrument drives with the implementation method of digital control pointer type meters, disclosed a kind of micro-stepping driving method of stepper motor as publishing house of Harbin Institute of Technology in " stepper motor and driving control system thereof ", the cost of this method is higher; Hardware circuit is comparatively complicated, is unfavorable for the maintenance of system; Not deviser's autonomous handling not high during at different application; May cause the wasting of resources of part hardware driving chip.

Summary of the invention

For the cost that overcomes in the existing digital control pointer type meters scheme higher, the hardware circuit complexity, hardware resource waste, the problem that versatility is not strong, the utility model has designed the scheme that a kind of new digital control pointer type meters directly drives.Can lower the complexity of hardware circuit, improve the versatility of system, can effectively reduce the cost of instrument simultaneously.

The technical scheme that the present invention solves its technical matters is: design a kind of automobile digital control pointer type meters drive unit, adopt the micro-stepping mode of operation of PWM modulator approach realization stepper motor, directly two-way stepping motor is realized the presentation control function of accurate pointer instrument; Use algorithm process on the software instead and realize the drive controlling of whole tachometer gage, adopt corresponding algorithm to solve non-linear acceleration and the deceleration of pointer in rotating.This instrument comprises: system initialization module, input pulse sampling module, the coordinated scheduling module of data sampling module, driving parameters computing module, PWM output driver module and each intermodule, it is characterized in that the coordinated scheduling module realizes the coordinated scheduling work to above-mentioned each module; Data sampling module is gathered the physical characteristics parameter of micro-step motor; Input pulse sampling module: carry out the input pulse sampling; The driving parameters computing module is gathering the angle that next data-switching becomes micro-step motor to turn over; The PWM driver module produces specific PWM train pulse, carries out the driving of micro-step motor.

The present invention has also designed a kind of automobile and has directly driven implementation method with digital control pointer type meters, it is characterized in that, said method comprising the steps of: the I/O mouth of system initialization module initialization MCU, and timer interrupts enabling; Data sampling module is gathered the physical characteristics parameter of micro-step motor; The angle parameter that next data-switching becomes micro-step motor to turn over will be gathered; In data list, search corresponding rotating speed; The PWM driver module receives driving data, produces specific PWM train pulse; Output pulse sequence drives micro-step motor and rotates.

The invention has the beneficial effects as follows: can when guaranteeing the pointer instrument quality, reaching higher technical indicator and reliability, effectively reduce cost, lower the complicacy of hardware circuit and improve the versatility of system.

Description of drawings

Fig. 1 is an algorithm entire block diagram of the present invention

Fig. 2 is data acquisition flow figure of the present invention

Fig. 3 is a driving parameters calculation flow chart of the present invention

Fig. 4 is that PWM of the present invention drives process flow diagram

Embodiment

The present invention is described further below in conjunction with the embodiment of accompanying drawing and digital control pointer type automobile engine speed indicator:

The overall algorithm model framework of present embodiment mainly comprises the coordinated scheduling module (1) of computing module (4), PWM output driver module (5) and each intermodule of system initialization module (2), data sampling module (3), driving parameters as shown in Figure 1.Scheduler module mainly realizes the co-ordination of above each module, and when tachometer gage just powered on, Coordination module was at first called initialization module, the I/0 mouth of initialization MCU, and timer interrupts enabling or the like; Then start data acquisition module, gather the speed data of engine rotation; After the acquisition time, call data computation module gathering the angle that next data-switching becomes micro-step motor to turn over; At last result of calculation is passed to the driving that the PWM driver module is carried out micro-step motor.In order to shorten the time interval between each data sampling, after the PWM driver module receives driving data, also started simultaneously data acquisition module, so can realize driving and gathering and carry out simultaneously, prevent from desultory phenomenon to occur when pointer from rotating in a period of time, allow pointer can realize wideer speed drive scope.The mode of mainly interrupting by trigger action in data acquisition realizes pulse calculating, because the non-normal off of time that interrupts, to the not significantly influence of driving of PWM.

Fig. 2 is input pulse sampling functional module, and the concrete method of sampling is carried out the input pulse sampling for adopting regularly the method for long count pulse number.Can guarantee the accuracy of sampling like this when the input pulse frequency is higher, the outside simultaneously small amount of interference pulse that seals in can not have big influence to the precision of sampling yet yet.

Figure 3 shows that the driving parameters computing module, realize the calculating of pointer target location, converse the rotating speed of engine by the pulsed frequency of sampling acquisition, go out the target turned position of pointer again according to calculation of parameter such as the maximum (top) speed of engine, the number of teeth, hard-overs, the target location and the current location of pointer are compared, calculate the corner that pointer will turn over, the speed that pointer rotates is to become certain proportionate relationship with corner, also promptly and the ratio that is varied to of engine speed.Adopted the mode of tabling look-up to realize the selection of different rotating speeds in the design proposal, promptly found out the rotating speed that it should be selected according to different pointer rotation distances.In the stepper motor rotation process acceleration there is certain restriction, when acceleration is excessive, can causes the rotating torque deficiency of motor, produce shake even step-out.Therefore, variation has been adopted the acceleration and deceleration process and has been taked nonlinear processing to avoid step-out to this process to speed of finger in this project, makes that also the rotation of pointer is more steady simultaneously, and visual effect is better.Determined to determine the speed change curves table that it is corresponding according to rotating speed of target with the difference of current rotating speed and the distance of rotation behind the rotating speed that concrete velocity variations is to realize by the frequency change that control pwm pulse dutycycle changes.

Fig. 4 is for producing the functional module of dynamic PWM output control pulse drive stepping motor micro-stepping running, principle by stepper motor micro-stepping driving, the drive current of knowing stepper motor is sinusoidal staircase waveform, the current effective value of this PWM drive waveforms is sinusoidal stepped change, and the electric signal waveform of driving shows as the width of pulse near sinusoidal variation.On the continuous process that drives, be exactly to send a certain fixed pulse sequence that constantly repeats to stepper motor to the driving of stepper motor.The modified tone system process of pulse train that should be fixing is exactly the key component among the design, and it has determined the smoothness that pointer is walked about, important technology indexs such as degree of accuracy.

Claims

1, a kind of automobile digital control pointer type meters drive unit, comprise: system initialization module, input pulse sampling module, the coordinated scheduling module of data sampling module, driving parameters computing module, PWM output driver module and each intermodule, it is characterized in that the coordinated scheduling module realizes the coordinated scheduling work to above-mentioned each module; Data sampling module is gathered the physical characteristics parameter of micro-step motor; Input pulse sampling module: carry out the input pulse sampling; The driving parameters computing module is gathering the angle that next data-switching becomes micro-step motor to turn over; The PWM driver module produces specific PWM train pulse, carries out the driving of micro-step motor.

2, automobile digital control pointer type meters according to claim 1 is characterized in that, the mode that described data acquisition module interrupts by trigger action realizes step-by-step counting.

3, a kind of automobile is characterized in that with the direct driving method of digital control pointer type meters, said method comprising the steps of: the I/O mouth of system initialization module initialization MCU, and timer interrupts enabling; Data sampling module is gathered the physical characteristics parameter of micro-step motor; The angle parameter that next data-switching becomes micro-step motor to turn over will be gathered; In data list, search corresponding rotating speed; The PWM driver module receives driving data, produces specific PWM train pulse; Output pulse sequence drives micro-step motor and rotates.

4, implementation method according to claim 3 is characterized in that, after the PWM driver module receives driving data, also starts data acquisition module simultaneously.

5, implementation method according to claim 3 is characterized in that, the target location and the current location of pointer compared, and calculates the corner that pointer will turn over and obtains angle parameter, searches the rotating speed that it should be selected according to different pointer rotation distances.