CN103837704A - Signal processing circuit used for processing vertical acceleration signals of vehicle - Google Patents

Abstract

The invention discloses a signal processing circuit used for processing vertical acceleration signals of a vehicle. The signal processing circuit is composed of a power module and a signal processing module. The signal processing module is composed of a signal preprocessing module, a low-pass module, an integration module, a high-pass part and a signal postprocessing module. The power module is composed of an MAX765 chip and an LM2575-5 chip. The power module supplies power to the signal processing module. The positive signals and the negative signals of the acceleration signals are input to the signal processing module, and speed signal output is completed finally after difference solving, low pass, integration, high pass, biasing and reversing amplification. A hardware filtering signal obtained through the signal processing circuit is quite similar to a true signal, and therefore the signal processing effect is good.

Description

Be applied to the signal processing circuit of vehicle vertical acceleration signal processing

Technical field

The present invention relates to a kind of signal processing circuit, particularly a kind of signal processing circuit that is applied to the processing of vehicle vertical acceleration signal.

Background technology

For the Suspension control of vehicle, accurately obtain fast that spring carries and nonspring carried mass vertical speed is prerequisite and the emphasis of controlling.

Summary of the invention

The object of this invention is to provide a kind of signal processing circuit that is applied to the processing of vehicle vertical acceleration signal, the present invention is directed to normal acceleration effective frequency, carry out integral filtering, remove high frequency and low-frequency noise signal, and then obtain effective velocity signal.For improving circuit adaptability, increase signal pre-treatment and post processing circuitry, with should be in unlike signal demand, add post processing circuitry in circuit rear end, on the one hand velocity voltage signal is increased to fixed bias, for permanent malleation input simultaneously, increase on the other hand polarity switching, be used for changing circuit output voltage polarity, and realize multichannel by short-circuit block and select, increase its adaptability.

The present invention is by power module, signal processing module composition, described signal processing module is by signal pre-processing module, low-pass module, integration module, high pass part and signal post-processing module composition, signal pre-processing module, low-pass module, integration module, high pass part and signal post-processing module are electrically connected successively, power module is to be made up of MAX765 chip and LM2575-5 chip, power module provides power supply for signal processing module, the ﹢ signal of acceleration signal and ﹣ signal input signal processing module, through asking poor, low pass, integration, high pass and biasing and commutation are amplified, finally complete rate signal output.

Beneficial effect of the present invention: hardware filtering signal and actual signal are very approaching, signal treatment effect is better.

Accompanying drawing explanation

Fig. 1 is theory diagram of the present invention.

Fig. 2 is low-frequency high-amplitude signal schematic representation.

Fig. 3 is low frequency and amplitude signal schematic representation.

Fig. 4 is true velocity signal schematic representation.

Fig. 5 is different circuit form Bode diagram.

Fig. 6 is power circuit module principle figure.

Fig. 7 is signal processing module circuit diagram.

Fig. 8 is dual power supply RC low-pass filter circuit figure.

Fig. 9 is dual power supply RC circuit of high pass filter figure.

Figure 10 is the circuit diagram of signal pre processing circuit.

Figure 11 is the circuit diagram of signal post-processing circuit.

Figure 12 is signal treatment effect comparison diagram.

Embodiment

As shown in Figure 1, the present embodiment is by power module 1, signal processing module 2 forms, described signal processing module 2 is by signal pre-processing module 21, low-pass module 22, integration module 23, high pass part 24 and signal post-processing module 25 form, signal pre-processing module 21, low-pass module 22, integration module 23, high pass part 24 and signal post-processing module 25 are electrically connected successively, power module 1 is to be made up of MAX765 chip and LM2575-5 chip, power module 1 provides power supply for signal processing module 2, power supply is 5V, 12V and ﹣ 12V, simultaneously, the ﹢ signal of acceleration signal and ﹣ signal input signal processing module 2, through asking poor, low pass, integration, high pass and biasing and commutation are amplified, finally complete rate signal output.

The circuit theory of signal processing module

Conventionally, effectively vehicle vertical velocity signal frequency range is 0.5～20Hz, in view of sensor signal is made up of multi-signal, comprises the signal of different frequency scope and different amplitudes, therefore, needs specific aim processing.The signal being obtained by acceleration signal integration roughly comprises following four parts: noise signal, low-frequency high-amplitude signal, low frequency and amplitude signal and high frequency signal by a narrow margin, wherein first three class signal is the undesired signal that needs eliminating, the 4th class is target vertical velocity signal, as shown in Figure 2, Figure 3 and Figure 4.

According to the analysis of aforementioned signal content, design low cost signal filtering integrating system, realizes the integration of acceleration signal to rate signal on the one hand, realizes on the other hand the elimination of undesired signal.In this case cost-saving, combine with basic low pass, Hi-pass filter, build based on acceleration transducer, be applied to the signal processing system that suspension vertical speed is obtained.

At this, for guaranteeing signal processing real-time, select first-order system to process, integration module adopts the low-pass filter composition that cutoff frequency is lower, at this, respectively low pass → integration → high pass circuit, low pass → low pass → high pass circuit to be analyzed, its Bode diagram is as shown in Figure 5.

Left figure in Fig. 5 is low pass → integration → high pass circuit, and the right figure in Fig. 5 is low pass → low pass → high pass circuit, and as shown in Figure 5, low pass → integration → high pass cannot realize high pass effect, and low pass → low pass → high pass circuit is better realized band and led to and carry out integration.Therefore, treatment circuit structure of the present invention adopts low pass (filtering), low pass (integration) and high pass composition.

The hardware of acceleration signal treatment circuit

Power module 1 is made up of MAX765 and LM2575-5 and peripheral circuit thereof, and for signal processing module 2 provides reference voltage (5V, 12V, ﹣ 12V), its circuit diagram as shown in Figure 6.

LM2575-5 voltage stabilizing chip, is the integrated stable voltage circuit that National Semiconductor produces, and is the desirable substitute products of traditional trifocal integrated regulator, and its maximum steady state error is 4%, and efficiency is 75%～88%, and input voltage is 5-42V.Carry out dividing potential drop by the steady 5V signal providing, for signal post-processing fixed bias in addition, as shown in Figure 1.

In view of rate signal has the feature of generating positive and negative voltage after high-pass filtering, need to carry out dual power supply to amplifier at this, for LM358 amplifier, its voltage input allowed band is ± 15V, therefore, design negative voltage generation module, provide ± 12V voltage at this based on MAX765.MAX765 chip, for+3V is to+15V input ,-12V output.At this, output voltage is adjustable, and as shown in formula (1), wherein RR5 selects at this pot that range is 100K, for adjusting negative voltage output

Vout=-1.5×RR5/R19 (1)

Signal processing module 2 schematic diagrams as shown in Figure 7, are the LM358 composition based on dual power supply, and circuit is divided into two parts, and downside is pre processing circuit and post processing circuitry, and upside is that signal is processed primary module.

Low-pass first order filter as shown in Figure 8, is low pass RC wave filter, transport function G as shown in formula (2), gain G _h, cut-off angular frequency w _h, as shown in formula (3), based on useful signal frequency, be 2 for make an uproar low-pass filter gain of filter at this, cutoff frequency is 17.5Hz, and for integration low-pass filtering, gain is 2, and cutoff frequency is 0.16Hz.

$G\left(s\right)=\frac{G_H}{1+(s/\mathrm{\ωH})}---\left(2\right)$

$G_H=1+\frac{R23}{R22},{\mathrm{\&omega;}}_H=\frac{1}{\mathrm{<figure-callout\; id="2"\; label="RH"\; filenames="140318102520.png,140318102553.png"\; state="\{\{state\}\}">RH</figure-callout>}2\&CenterDot;\mathrm{CH}2}---\left(3\right)$

Single order Hi-pass filter as shown in Figure 9, is high pass RC wave filter, transport function Z as shown in formula (4), gain G _z, cut-off angular frequency wZ, as shown in formula (5), based on useful signal frequency, is 2 for make an uproar low-pass filter gain of filter at this, cutoff frequency is 0.48Hz.

$Z\left(s\right)=\frac{{\mathrm{<figure-callout\; id="1"\; label="G\; Z"\; filenames="140318102544.png"\; state="\{\{state\}\}">G</figure-callout>}}_Z}{1+({\mathrm{\&omega;}}_Z/s)}---\left(4\right)$

$G_Z=\frac{R18}{R17},{\mathrm{\&omega;}}_Z=\frac{1}{\mathrm{<figure-callout\; id="2"\; label="RZ"\; filenames="140318102520.png,140318102553.png"\; state="\{\{state\}\}">RZ</figure-callout>}2\&CenterDot;\mathrm{CZ}2}---\left(5\right)$

Signal pre processing circuit as shown in figure 10, is inputted for the difference that realizes acceleration transducer signals.Output voltage is (V2_In+)-(V2_In-), reduces common-mode signal.

Signal post-processing circuit as shown in figure 11, comprises adding circuit and commutation circuit.The offset signal that adding circuit is input as Hi-pass filter output signal and the generation of LM2575-5 process pot, realizes the output of fixed bias signal, is convenient to controller signals collection.Commutation circuit act as signal sign is converted, regulate enlargement factor by pot RR4 simultaneously, realize multi-signal output, increase circuit adaptability, export selection at this by 3pin short-circuit block, from Figure 12, V2_out_1 and V2_out_2 select a road to export, as shown in Fig. 1 theory diagram.

As shown in figure 12, process and ideal signal comparative analysis figure for actual hardware circuit signal, as shown in Figure 12, hardware filtering signal and actual signal are very approaching, and signal treatment effect is better, has verified the validity of circuit of the present invention.

Claims (1)

1. one kind is applied to the signal processing circuit of vehicle vertical acceleration signal processing, it is characterized in that: formed by power module and signal processing module, described signal processing module is by signal pre-processing module, low-pass module, integration module, high pass part and signal post-processing module composition, signal pre-processing module, low-pass module, integration module, high pass part and signal post-processing module are electrically connected successively, power module is to be made up of MAX765 chip and LM2575-5 chip, power module provides power supply for signal processing module, the ﹢ signal of acceleration signal and ﹣ signal input signal processing module, through asking poor, low pass, integration, high pass and biasing and commutation are amplified, finally complete rate signal output.

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