JP2018155696A - Road surface determination device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique that is not affected by an inclination of a road the road surface even at low speed.SOLUTION: Upon applying driving torque, drive shaft (DS) twisting oscillation occurs in a state where a tire 16 is gripped, and in a state where the tire is skidded (road surface μstate), twisting of a DS spring is released by tire skidding, and the DS twisting oscillation disappears. When the DS twisting oscillation occurs, an oscillation mode made up of engine block (E/G) back-and-forth resonance) and DS twisting resonance appears on an E/G block 10 and the spring, and when the DS twisting oscillation disappears, single oscillation of the E/G back-and-forth resonance appears. By checking the oscillation mode of each portion, a determination of the road surface is made.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a road surface determination device.

  Conventionally, techniques for estimating a road surface friction coefficient and a road surface friction state have been proposed.

  Patent Document 1 describes a technique for improving estimation accuracy by using a longitudinal acceleration in which an influence of a gravity component due to a road gradient is removed in a road surface friction state estimation device based on a vehicle longitudinal acceleration during braking / driving. .

  Patent Document 2 detects and detects the maximum value of the wheel acceleration obtained by differentiating the maximum value of the throttle opening and the detected wheel speed from the start of acceleration to the road surface determination when accelerating from a traveling state of a certain vehicle speed or higher. A technique is described in which a road surface is determined by determining which region the value is in.

JP 2013-28258 A JP-A-10-299529

  In the technique described in Patent Document 1, braking / driving is started on a flat road, and if it enters a slope immediately after that, the influence of the gravitational acceleration component cannot be removed. Further, since the road surface gradient is not always constant, there is a problem that the correction value based on the front-rear reference value is not correctly performed and the road surface friction state is not correctly estimated.

  In the technique described in Patent Document 2, wheel speed detection is usually performed by using a rotational speed detection slit in which an electromagnetic pickup and convex teeth are arranged at equal intervals, and the approach of the convex teeth of the slit is detected by the electromagnetic pickup. If the rotation speed is low, the back electromotive force of the electromagnetic pickup becomes small, making it difficult to detect the speed, and the number of teeth of the convex teeth is limited, so that the detection accuracy of the wheel speed decreases as the rotation speed decreases. As a result, there is a problem that the road surface cannot be determined unless the vehicle speed exceeds a certain level.

  The present invention has been made in view of such problems, and the object thereof is to determine the road surface with high accuracy without being affected by the inclination of the road surface and without being influenced by the speed (even if it is at a low speed). It is to provide the technology to obtain.

  The present invention includes a vibration detection unit that detects a vibration component of engine longitudinal resonance, a detection unit that detects acceleration / deceleration torque, a storage unit that stores a torque reference value that reaches a friction coefficient μmax for each road surface, and the vibration detection unit. Determining means for determining a road surface condition using the acceleration / deceleration torque and the torque reference value at the time when the vibration component is detected at the predetermined position of the drive shaft corresponding to the current transmission gear stage. The road surface determination device does not determine the road surface state when the torsional resonance frequency and the engine longitudinal resonance frequency coincide with each other.

  In one embodiment of the present invention, the vibration detection means includes engine longitudinal acceleration detection means for detecting longitudinal acceleration of the engine, and detects the vibration component from the detected longitudinal acceleration of the engine.

  In another embodiment of the present invention, the detection unit detects a throttle opening as the acceleration / deceleration torque, and the determination unit detects the vibration component when the throttle opening changes and a predetermined engine longitudinal resonance. When the frequency matches, the road surface condition is determined.

  In still another embodiment of the present invention, the vibration detecting means includes a sprung longitudinal acceleration detecting means for detecting a longitudinal acceleration on a spring of the vehicle, and detects the vibration component from the detected longitudinal acceleration on the spring. To do.

  In still another embodiment of the present invention, the detection unit detects a throttle opening as the acceleration / deceleration torque, and the determination unit detects the vibration component when the throttle opening changes and a predetermined engine front and rear. The road surface state is determined when the resonance frequency matches.

Further, the present invention provides a vibration detection means for detecting a vibration component of drive shaft torsional resonance, a detection means for detecting acceleration / deceleration torque, a storage means for storing a torque reference value reaching a friction coefficient μ _max for each road surface, A road surface determination apparatus comprising: determination means for determining a road surface state using the acceleration / deceleration torque and the torque reference value at the time when the vibration component is detected by the vibration detection means.

  In still another embodiment of the present invention, the vibration detection means includes torque detection means for detecting the torque of the drive shaft, and detects the vibration component from the detected torque.

  In still another embodiment of the present invention, the detection means detects a throttle opening as the acceleration / deceleration torque, and the determination means includes the vibration component at the time when the throttle opening changes and a current transmission gear. The road surface state is determined when the predetermined drive shaft torsional resonance frequency corresponding to the stage matches.

  In still another embodiment of the present invention, the vibration detection unit includes a rotation speed detection unit that detects a rotation speed of the engine, and detects the vibration component from the detected rotation speed of the engine.

  In still another embodiment of the present invention, the detection means detects a throttle opening as the acceleration / deceleration torque, and the determination means includes the vibration component at the time when the throttle opening changes and a current transmission gear. The road surface state is determined when the predetermined drive shaft torsional resonance frequency corresponding to the stage matches.

  In still another embodiment of the present invention, the vibration detecting unit further includes a band pass filter circuit that extracts a specific frequency component, and detects the vibration component from an output of the band pass filter circuit.

  In still another embodiment of the present invention, the vibration detection means further includes a fast Fourier transform circuit, and detects the vibration component from the output of the fast Fourier transform circuit.

  In the present invention, instead of determining the road surface using the tire wheel speed and the tire longitudinal force in contact with the road surface, which has been thought to have a deep causal relationship with the road surface μ as in the prior art, the engine is based on the difference in tire grip and slip. The road surface is determined using the presence / absence of vibration of longitudinal resonance, and specifically, detection signals such as engine rotation speed, sprung longitudinal acceleration, engine longitudinal acceleration, and drive shaft torque are used. In the present invention, since the road surface is determined using the presence or absence of vibration, the influence of the gravity g component can be eliminated. The presence or absence of vibration can be detected even if the vehicle speed is zero.

  According to the present invention, it is possible to determine the road surface state with high accuracy without being affected by the road surface inclination and without being influenced by the speed.

It is a principle explanation schematic diagram of an embodiment. It is a figure which shows the relationship between the drive shaft torque in the high μ road and the low μ road, and the slip ratio and the road surface μ. It is simulation explanatory drawing of embodiment. It is a figure which shows the actual vehicle test result of Embodiment 1. 1 is a configuration block diagram of Embodiment 1. FIG. 6 is another configuration block diagram of the first embodiment. FIG. 3 is a processing flowchart of the first embodiment. It is a figure which shows the actual vehicle test result of Embodiment 2. 6 is a configuration block diagram of Embodiment 2. FIG. 10 is a processing flowchart of the second embodiment. It is a figure which shows the actual vehicle test result of Embodiment 3. FIG. 9 is a configuration block diagram of a third embodiment. 10 is a processing flowchart of the third embodiment. It is a figure which shows the actual vehicle test result of Embodiment 4. FIG. 6 is a configuration block diagram of a fourth embodiment. 10 is a process flowchart of the fourth embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<Basic principle>
First, the basic principle of the embodiment will be described.

  In the embodiment, the road surface determination method detects the presence or absence of drive shaft (DS) vibration attenuation due to a difference in tire grip and slip at each part of the vehicle, and determines the road surface with reference to the applied throttle opening. Although an acceleration sensor is used as part of the vibration measurement as in the past, it is not affected by gravitational acceleration because it focuses on the frequency of the AC component without referring to the direct current (DC) component. In addition, since detection values other than the transmission (T / M) rotation speed can be obtained from the vehicle stop state, the road surface can be determined at the time of starting from the vehicle stop.

When driving torque is applied, drive shaft (DS) torsional vibration occurs when the tire is gripped. On the other hand, when the tire slips (road surface μ _max (maximum coefficient of friction) state) DS) Torsion of the spring is released and the drive shaft (DS) torsional vibration disappears. When drive shaft (DS) torsional vibration occurs, combined vibration of engine (E / G) block longitudinal resonance (E / G longitudinal resonance) and drive shaft (DS) torsional resonance on the engine (E / G) block and spring A mode appears, and when the drive shaft (DS) torsional vibration disappears, a single vibration of engine (E / G) longitudinal resonance appears. Also, when drive shaft (DS) torsional vibration occurs, torsional vibration is generated by the drive shaft (DS) torque, and rotation speed of the engine (E / G) and transmission (T / M) is driven by drive shaft (DS) torque vibration. Variations appear.

Therefore, by checking the vibration mode of each part based on the engine (E / G) block, sprung front and rear, engine (E / G) or transmission (T / M) rotation speed, and drive shaft (DS) torque signal. It is possible to know indirectly whether the tire is in a grip state, and compare the acceleration / deceleration torque (that is, the throttle opening) with the torque reference value that is μ _max (the maximum value of the friction coefficient μ) provided for each road surface. Then, the current traveling road surface can be determined.

  FIG. 1 shows a connection relationship among an engine (E / G) block 10, a transmission (T / M) 12 to a drive shaft (DS) 14 (powertrain (PT) system), a tire 16, a vehicle body 18, and a mount 20. FIG.

  In FIG. 1, a high μ road when the slip ratio of the tire 16 and the road surface μ characteristic, which is the relationship between the slip ratio and the road surface μ characteristic, is set and the engine torque is given in steps from the 0 Nm state. Measure the drive shaft (DS) torque in the case of (dry road (dry)) and low μ road (ice top road (ice)).

  FIG. 2 shows an example of a slip ratio-road surface μ characteristic, and drive shaft (DS) torque on a high μ road and a low μ road.

  FIG. 3A to FIG. 3K show the results of computer simulation given predetermined medium-sized vehicle specifications. In the figure, engine (E / G) torque, drive shaft (D / S) torque, vehicle speed, wheel speed, slip ratio, road surface μ, sprung longitudinal acceleration, engine (E / G) longitudinal acceleration, engine (E / G) from the top E / G) Indicates the pitch angular acceleration, unsprung longitudinal acceleration, and tire driving force. The engine (E / G) block is shown as a behavior with two degrees of freedom in front and rear and pitch. Further, the unsprung and engine (E / G) longitudinal accelerations are shown as relative accelerations after the sprung longitudinal acceleration.

As shown in FIG. 3, on the low μ road (ice top road), as the throttle is applied, the road surface μ _max is reached as shown in FIG. 3 (f), so that the engine (E / G) block is shown in FIG. 3 (h). The longitudinal acceleration becomes a single vibration state of longitudinal resonance. In the figure, this simple vibration is shown as “E / G resonance period”. The reason for this simple vibration is that the torsion of the drive shaft (DS) spring is released as the tire slips, and the subsequent excitation from the spring due to the torsional vibration of the drive shaft (DS) is eliminated.

  On the other hand, on the high μ road (dry road), the drive shaft (DS) spring torsion is maintained because the tire is in a grip state, and the drive shaft (DS) torsion resonance based on the upstream side of the drive shaft (DS) is generated. The top is vibrated. As a result, as shown in FIG. 3 (h), the longitudinal acceleration of the engine (E / G) block has two frequencies: a drive shaft (DS) torsional frequency from the spring and an engine (E / G) longitudinal resonance. It becomes a vibration.

  Therefore, if the simple vibration state of the longitudinal acceleration of the engine (E / G) block is detected and the acceleration / deceleration torque (throttle opening) at the time of the simple vibration detection is compared with a predetermined torque reference value, road surface discrimination becomes possible. Normally, the resonance of the engine (E / G) block before and after is around 10 Hz, so you only need to pay attention to vibrations in this frequency range, and remove other low frequency components from direct current (DC) to several Hz with a bandpass filter. It is possible to solve the problem of erroneous determination due to gravitational acceleration.

  Here, in FIG. 3, a solid line is shown in the vertical direction between the engine (E / G) longitudinal acceleration shown in FIG. 3 (h) and the sprung longitudinal acceleration shown in FIG. It can be seen that the convex part of the engine (E / G) longitudinal acceleration and the concave part (or concave and convex) of the sprung longitudinal acceleration when traveling on the road (ice top road) coincide with each other in time. This is because the engine (E / G) block and the sprung spring are connected by the front and rear springs in the vehicle traveling direction, and as a result, both are subjected to acting force and reaction force.

  Therefore, instead of engine (E / G) longitudinal acceleration, focus on sprung longitudinal acceleration, and determine whether the engine (E / G) longitudinal resonance is a simple vibration based on the bandpass filter processing value. The acceleration / deceleration torque (throttle opening) is compared with a torque reference value (throttle reference value) to determine the road surface.

  In addition, since the drive shaft (DS) torsional vibration continues on the high μ road (dry road), the drive shaft (DS) torque is measured and the drive shaft (DS) corresponds to the transmission (T / M) gear ratio. It is also possible to determine whether the vibration is a torsional frequency, and to determine the road surface by comparing the acceleration / deceleration torque (throttle opening) at the time of determination with a torque reference value (throttle reference value).

  Also, when drive shaft (DS) torsional torque is generated, the counter torque is handled on the engine (E / G) block side, so the drive shaft is driven to engine (E / G) rotation speed or transmission (T / M) rotation speed. (DS) Rotational speed fluctuation corresponding to torsional vibration occurs. Therefore, it is also possible to determine whether the rotational speed includes torsional vibration of the drive shaft (DS), and to determine the road surface by referring to the acceleration / deceleration torque (throttle opening) at the time of determination with the torque reference value (throttle reference value). it can.

  The above is the basic principle of the embodiment. Next, the road surface determination of the embodiment will be described in more detail.

<Embodiment 1>
FIG. 4 shows the actual vehicle test results when the transmission (T / M) gear is chip-in accelerated from the coast state on the high μ road and the low μ road with the low side gear set. In the figure, engine (E / G) torque estimated value, sprung longitudinal acceleration, and engine (E / G) longitudinal acceleration are shown from the top. The engine (E / G) longitudinal acceleration indicates a waveform as a result of the bandpass filter processing.

  When driving on a low μ road, the band pass value of the longitudinal acceleration of the engine (E / G) immediately after chip-in is a single vibration state of the longitudinal resonance of the engine (E / G). It can be seen that the road surface can be determined by comparing the throttle opening with the throttle level value.

  FIG. 5 shows a configuration block diagram of the present embodiment. The device includes a transmission (T / M) gear set value detector 30, a throttle opening detector 32, an engine (E / G) longitudinal acceleration detector 34, a bandpass filter circuit 36, an engine (E / G) longitudinal resonance frequency. A storage circuit 38, a vibration frequency detection circuit 40, a throttle opening level determination circuit 42, a throttle opening level storage circuit 44, an engine (E / G) front / rear resonance frequency comparison circuit 46, and a road surface determination circuit 48 are provided.

  The transmission (T / M) gear set value detector 30 detects the gear stage of the transmission (T / M) and outputs it to the road surface determination circuit 48.

  The throttle opening detector 32 detects the throttle opening as acceleration / deceleration torque and outputs the detected throttle opening to the vibration frequency detection circuit 40 and the throttle opening level determination circuit 42.

  The engine (E / G) longitudinal acceleration detector 34 detects the engine (E / G) longitudinal acceleration and outputs it to the bandpass filter circuit 36.

  As described above, the bandpass filter circuit 36 extracts a signal having a specific frequency (near 10 Hz) from the longitudinal acceleration of the engine (E / G), removes other frequency components as noise, and detects the vibration frequency detection circuit 40. Output to.

  The vibration frequency detection circuit 40 detects the vibration frequency when the throttle opening changes based on the throttle opening detection signal from the throttle opening detector 32 and the output signal of the bandpass filter circuit 36 to detect the engine (E / E G) Output to the front-rear resonance frequency matching circuit 46.

  The engine (E / G) longitudinal resonance frequency storage circuit 38 stores the engine (E / G) longitudinal resonance value in advance.

  The engine front / rear (E / G) front / rear resonance frequency comparison circuit 46 is detected by the engine (E / G) front / rear resonance frequency stored in the engine (E / G) front / rear resonance frequency storage circuit 38 and the vibration frequency detection circuit 40. The vibration frequency is compared with each other, and it is determined whether or not both are substantially the same.

  The throttle opening level judgment circuit 42 compares the detected throttle opening with the throttle opening (throttle reference value) stored in the throttle opening storage circuit 44 and becomes μmax of each road surface. Output to the road surface determination circuit 48.

  The road surface determination circuit 48 includes a gear detected by the transmission (T / M) gear set value detector 30, a verification result of the engine (E / G) front / rear resonance frequency verification circuit 46, and a throttle opening level determination circuit 42. Based on the determination result, the road surface is determined and output. In other words, considering the detected transmission (T / M) gear stage, the result of the throttle opening when the detected vibration frequency substantially matches the engine (E / G) longitudinal resonance frequency is output as the road surface determination result. To do.

  Depending on the transmission (T / M) gear stage, the drive shaft (DS) torsional resonance frequency approaches the engine (E / G) longitudinal resonance frequency, making it difficult to determine the road surface by detecting the engine (E / G) longitudinal resonance frequency. (If the engine (E / G) longitudinal vibration of the same frequency occurs on the high μ road and the low μ road, it may be difficult to distinguish both) Drive shaft (DS) considering the gear stage The accuracy of road surface determination can be ensured by not performing road surface determination at a specific gear stage where the torsional resonance frequency approaches the engine (E / G) front-rear resonance frequency.

  Specifically, the engine (E / G) longitudinal acceleration detector 34 includes an acceleration sensor, and includes a bandpass filter circuit 36, an engine (E / G) longitudinal resonance frequency storage circuit 38, a vibration frequency detection circuit 40, a throttle opening. The degree level determination circuit 42, the throttle opening degree storage circuit 44, the engine (E / G) front / rear resonance frequency comparison circuit 46, and the road surface determination circuit 48 are configured by an ECU (electronic control circuit) including one or more processors and a memory. Is done. The processor functions as the vibration frequency detection circuit 40, the road surface determination circuit 48, or the like by executing a processing program stored in a ROM or the like. The memory stores an engine (E / G) longitudinal resonance frequency and a throttle opening that is μmax of each road surface, and functions as an engine (E / G) longitudinal resonance frequency storage circuit 38 and a throttle opening storage circuit 44.

  In the configuration block diagram of FIG. 5, the vibration frequency of the longitudinal acceleration of the engine (E / G) when the throttle opening is changed is detected by combining the band-pass filter circuit 36 and the vibration frequency detection circuit 40. The vibration frequency may be detected using (FFT).

  FIG. 6 shows a block diagram of the configuration in this case. Instead of the bandpass filter circuit 36, the vibration frequency detection circuit 40, and the engine (E / G) front-rear resonance frequency matching circuit 46 in FIG. 5, an FFT circuit 50 and a gain reading circuit 52 for the engine (E / G) front-rear resonance frequency are provided. Prepare.

  The FFT circuit 50 performs fast Fourier transform (FFT) on the detected engine (E / G) longitudinal acceleration signal at the timing when the throttle opening changes, and outputs it to the gain reading circuit 52 for the engine (E / G) longitudinal resonance frequency. To do.

  The engine (E / G) front-rear resonance frequency gain reading circuit 52 reads the FFT gain at the resonance frequency stored in the engine (E / G) front-rear resonance frequency storage circuit 38, and when this exceeds a predetermined threshold value. The gain is output to the road surface determination circuit 48.

  The road surface determination circuit 48 performs road surface determination using the determination result from the gain reading circuit 52 of the engine (E / G) front-rear resonance frequency and outputs the result.

  FIG. 7 shows a processing flowchart of the present embodiment. FIG. 6 is a process flowchart executed by the configuration block shown in FIG. 5. FIG.

  First, an initial value for performing road surface determination is set (S101). That is, an engine (E / G) longitudinal resonance value, a drive shaft (DS) torsional resonance frequency reference table for a transmission (T / M) gear stage, a bandpass filter constant, and the like are set.

  Next, the gear position (gear position) is detected by the transmission (T / M) gear set value detector 30 (S102). The detected gear stage is supplied to the road surface determination circuit 48.

  The road surface determination circuit 48 reads out the drive shaft (DS) torsional resonance frequency corresponding to the detected gear stage from the reference table (S103), and sets the read drive shaft (DS) torsional resonance frequency and the initial value as the engine ( E / G) It is determined whether the longitudinal resonance values are substantially equal (S104). When both are substantially equal, the process after S102 is repeated and road surface determination is not performed, and when both are not substantially equal, the process proceeds to the next process. As described above, this determination processing is performed so that the road surface determination is not performed at a specific gear stage in which the drive shaft (DS) torsional resonance frequency approaches the engine (E / G) front-rear resonance frequency. .

  If the two are not substantially equal (NO in S104), the throttle opening detector 32 detects the throttle opening (S105), and the engine (E / G) longitudinal acceleration detector 34 detects the engine (E / G) longitudinal acceleration. Detect (S106). The bandpass filter circuit 36 performs bandpass filter processing on the detected engine (E / G) longitudinal acceleration (S107).

  Next, the vibration frequency detection circuit 40 determines whether or not the throttle opening has changed (S108), and if the throttle opening has changed (YES in S108), the engine (E / G) A vibration frequency is detected from the longitudinal acceleration signal (S109).

  Next, the engine (E / G) front-rear resonance frequency comparison circuit 46 determines whether or not the detected vibration frequency substantially matches the engine (E / G) front-rear resonance value set as an initial value ( S110). When the detected signal frequency substantially matches the engine (E / G) front-rear resonance frequency (YES in S110), the throttle opening level determination circuit 42 determines the throttle opening level (S111), and the road surface is determined. (S112). That is, the throttle opening is compared with the throttle opening that is μmax of each road surface stored in the throttle opening storage circuit 44, and the corresponding road surface is determined and output.

<Embodiment 2>
FIG. 8 shows an actual vehicle test result in the present embodiment. In the figure, an estimated engine (E / G) torque value, a signal obtained by subjecting the engine (E / G) longitudinal acceleration signal to bandpass filter processing, and a signal obtained by subjecting the sprung longitudinal acceleration signal to bandpass filter processing are shown from the top. The road surface judgment can be performed by utilizing the fact that the bandpass filter processing value of the sprung acceleration corresponds to the single vibration state of the longitudinal resonance of the engine (E / G).

  FIG. 9 shows a configuration block diagram of the present embodiment. The apparatus includes a transmission (T / M) gear set value detector 30, a throttle opening detector 32, a sprung longitudinal acceleration detector 35, a bandpass filter circuit 36, an engine (E / G) longitudinal resonance frequency storage circuit 38, A vibration frequency detection circuit 40, a throttle opening level determination circuit 42, a throttle opening storage circuit 44, an engine (E / G) front-rear resonance frequency comparison circuit 46, and a road surface determination circuit 48 are provided. The difference from FIG. 5 is that a sprung longitudinal acceleration detector 35 is provided instead of the engine (E / G) longitudinal acceleration detector 34.

  The transmission (T / M) gear set value detector 30 detects the gear stage of the transmission (T / M) and outputs it to the road surface determination circuit 48.

  The throttle opening detector 32 detects the throttle opening and outputs it to the vibration frequency detection circuit 40 and the throttle opening level determination circuit 42.

  The sprung longitudinal acceleration detector 35 detects the longitudinal acceleration on the spring and outputs it to the bandpass filter circuit 36.

  The band-pass filter circuit 36 extracts a signal having a specific frequency (near 10 Hz) from the longitudinal acceleration on the spring, removes other frequency components as noise, and outputs it to the vibration frequency detection circuit 40.

  The vibration frequency detection circuit 40 detects the vibration frequency when the throttle opening changes based on the throttle opening detection signal from the throttle opening detector 32 and the output signal of the bandpass filter circuit 36 to detect the engine (E / E G) Output to the front-rear resonance frequency matching circuit 46.

  The engine (E / G) longitudinal resonance frequency storage circuit 38 stores the engine (E / G) longitudinal resonance value in advance.

  The engine front / rear (E / G) front / rear resonance frequency comparison circuit 46 is detected by the engine (E / G) front / rear resonance frequency stored in the engine (E / G) front / rear resonance frequency storage circuit 38 and the vibration frequency detection circuit 40. The vibration frequency is compared with each other, and it is determined whether or not both are substantially the same.

  The throttle opening level determination circuit 42 compares the detected throttle opening with the throttle opening that is stored in the throttle opening storage circuit 44 and becomes μmax of each road surface, and the result is sent to the road surface determination circuit 48. Output.

  The road surface determination circuit 48 includes a gear detected by the transmission (T / M) gear set value detector 30, a verification result of the engine (E / G) front / rear resonance frequency verification circuit 46, and a throttle opening level determination circuit 42. Based on the determination result, the road surface is determined and output. In other words, considering the detected transmission (T / M) gear stage, the result of the throttle opening when the detected vibration frequency substantially matches the engine (E / G) longitudinal resonance frequency is output as the road surface determination result. To do.

  FIG. 10 shows a processing flowchart of the present embodiment.

  First, an initial value for performing road surface determination is set (S201). That is, an engine (E / G) longitudinal resonance value, a drive shaft (DS) torsional resonance frequency reference table for a transmission (T / M) gear stage, a bandpass filter constant, and the like are set.

  Next, the gear position (gear position) is detected by the transmission (T / M) gear set value detector 30 (S202). The detected gear stage is supplied to the road surface determination circuit 48.

  The road surface determination circuit 48 reads the drive shaft (DS) torsional resonance frequency corresponding to the detected gear stage from the reference table (S203), and reads the drive shaft (DS) torsional resonance frequency and the engine (set as an initial value). E / G) It is determined whether the longitudinal resonance values are substantially equal (S204). When both are substantially equal, the process after S202 is repeated and road surface determination is not performed, and when both are not substantially equal, the process proceeds to the next process. This determination processing is to prevent road surface determination from being performed at a specific gear stage in which the drive shaft (DS) torsional resonance frequency approaches the engine (E / G) front-rear resonance frequency.

  When the two are not substantially equal (NO in S204), the throttle opening is detected by the throttle opening detector 32 (S205), and the longitudinal acceleration on the spring is detected by the sprung longitudinal acceleration detector 35 (S206). The band pass filter circuit 36 performs a band pass filter process on the detected longitudinal acceleration on the spring (S207).

  Next, the vibration frequency detection circuit 40 determines whether or not the throttle opening has changed (S208). If the throttle opening has changed (YES in S208), the longitudinal acceleration on the spring subjected to the bandpass filter processing is determined. The vibration frequency is detected from the signal (S209).

  Next, the engine (E / G) front-rear resonance frequency comparison circuit 46 determines whether or not the detected vibration frequency substantially matches the engine (E / G) front-rear resonance value set as an initial value ( S210). When the detected signal frequency substantially coincides with the engine (E / G) front-rear resonance frequency (YES in S210), the throttle opening level determination circuit 42 determines the throttle opening level (S211) and determines the road surface. (S212). That is, the throttle opening is compared with the throttle opening that is μmax of each road surface stored in the throttle opening storage circuit 44, and the corresponding road surface is determined and output.

<Embodiment 3>
FIG. 11 shows actual vehicle test results in the present embodiment. In the figure, engine (E / G) torque and drive shaft (DS) torque are shown from the top. The drive shaft (DS) torque measurement value of the high μ road shows the vibration waveform of the drive shaft (DS) torsional resonance determined by the transmission (T / M) gear and does not appear on the low μ road. It is possible to determine the road surface by detecting the presence or absence of torsional resonance and comparing the throttle opening at the time of detection with the throttle level value.

  Note that when detecting vibration of the drive shaft (DS) torsional resonance, noise may be removed using a bandpass filter processing value of several Hz to several tens Hz of the drive shaft (DS) torque.

  FIG. 12 shows a configuration block diagram of the present embodiment. The apparatus includes a transmission (T / M) gear set value detector 30, a throttle opening detector 32, a drive shaft (DS) torque detector 33, a drive shaft (DS) torsional resonance frequency storage circuit 39, and a vibration frequency detection circuit 40. , A throttle opening level determination circuit 42, a throttle opening storage circuit 44, a drive shaft (DS) torsional resonance frequency matching circuit 47, and a road surface determination circuit 48.

  The transmission (T / M) gear set value detector 30 detects the gear stage of the transmission (T / M) and outputs it to the road surface determination circuit 48.

  The throttle opening detector 32 detects the throttle opening and outputs it to the vibration frequency detection circuit 40 and the throttle opening level determination circuit 42.

  The drive shaft (DS) torque detector 33 detects the torque of the drive shaft (DS) and outputs it to the vibration frequency detection circuit 40.

  The vibration frequency detection circuit 40 detects the vibration frequency when the throttle opening changes based on the throttle opening detection signal from the throttle opening detector 32 and the output signal of the drive shaft (DS) torque detector 33. Output to the drive shaft (DS) torsional resonance frequency matching circuit 47.

  The drive shaft (DS) torsional resonance frequency storage circuit 39 stores in advance the torsional resonance value of the drive shaft (DS) for each gear stage.

  The drive shaft (DS) torsional resonance frequency check circuit 47 stores the drive shaft (DS) torsional resonance frequency corresponding to the detected gear stage and the vibration frequency detection stored in the drive shaft (DS) torsional resonance frequency storage circuit 39. The vibration frequency detected by the circuit 40 is collated, and it is determined whether or not both are substantially the same.

  The throttle opening level determination circuit 42 compares the detected throttle opening with the throttle opening that is stored in the throttle opening storage circuit 44 and becomes μmax of each road surface, and the result is sent to the road surface determination circuit 48. Output.

  The road surface determination circuit 48 determines and outputs the road surface based on the verification result of the drive shaft (DS) torsional resonance frequency verification circuit 47 and the determination result of the throttle opening level determination circuit 42. That is, the determination result of the throttle opening when the detected vibration frequency substantially coincides with the drive shaft (DS) torsional resonance frequency is output as the road surface determination result.

  Specifically, the drive shaft (DS) torque detector 33 is composed of a torque sensor, and a drive shaft (DS) torsional resonance frequency storage circuit 39, a vibration frequency detection circuit 40, a throttle opening level determination circuit 42, a throttle opening. The storage circuit 44, the drive shaft (DS) torsional resonance frequency matching circuit 47, and the road surface determination circuit 48 are configured by an ECU (electronic control circuit) including one or a plurality of processors and a memory. The processor functions as the vibration frequency detection circuit 40, the road surface determination circuit 48, or the like by executing a processing program stored in a ROM or the like. The memory stores a drive shaft (DS) torsional resonance frequency and a throttle opening that is μmax of each road surface, and functions as a drive shaft (DS) torsional resonance frequency storage circuit 39 and a throttle opening degree storage circuit 44.

  As described above, a band-pass filter circuit may be further provided between the drive shaft (DS) torque detector 33 and the vibration frequency detection circuit 40.

  FIG. 13 shows a processing flowchart of the present embodiment.

  First, an initial value for performing road surface determination is set (S301). That is, a drive shaft (DS) torsional resonance frequency reference table, a bandpass filter constant, etc. are set for the transmission (T / M) gear stage.

  Next, the gear position is detected by the transmission (T / M) gear set value detector 30 (S302), and the throttle opening is detected by the throttle opening detector 32 (S303).

  Further, the drive shaft (DS) torque detector 33 detects the drive shaft (DS) torque (S304), the band pass filter circuit performs band pass filtering processing (S305), and outputs the result to the vibration frequency detection circuit 40.

  The vibration frequency detection circuit 40 determines whether or not the throttle opening has changed based on the detection signal from the throttle opening detector 32 (S306), and when the throttle opening changes, the drive shaft (DS) torque. The vibration frequency is detected from the signal (S307).

  Next, the drive shaft (DS) torsional resonance frequency comparison circuit 47 determines whether or not the torsional frequency from the driveshaft (DS) torsional resonance frequency storage circuit 39 and the detected vibration frequency substantially coincide (S308). ), And outputs the determination result to the road surface determination circuit 48.

  On the other hand, the throttle opening level determination circuit 42 compares the detected throttle opening with the throttle opening that is stored in the throttle opening storage circuit 44 and becomes μmax of each road surface, and the result is a road surface determination circuit. 48 (S309).

  The road surface determination circuit 48 determines the road surface using the determination result in the throttle opening level determination circuit 42 when the drive shaft (DS) torsional resonance frequency comparison circuit 47 determines that they match, and outputs the road surface (S310).

<Embodiment 4>
FIG. 14 shows the actual vehicle test results of this embodiment. In the figure, engine (E / G) torque, drive shaft (DS) torque, and engine (E / G) rotation speed are shown from the top. The engine (E / G) rotation speed indicates the result of applying a band pass filter of several Hz to several tens Hz. As shown in this figure, the engine (E / G) rotation speed has a component with the same period as the high μ road drive shaft (DS) torsional vibration.

  Therefore, it is possible to detect the drive shaft (DS) torsional vibration based on the engine (E / G) rotational speed bandpass filter processing value, and to determine the road surface by comparing the throttle opening at the time of detection with the throttle level value. Instead of the engine (E / G) rotation speed, the transmission (T / M) rotation speed may be used.

  In FIG. 14, there is a phase shift in the bandpass filter value of the engine (E / G) rotation speed with respect to the drive shaft (DS) torque waveform, and the drive shaft (DS) torque is delayed by 270 ° from the point when it reaches the peak. At that point, the engine (E / G) rotation speed has reached a convex peak. This is because the drive shaft (DS) torque is a load torque on the engine (E / G) rotation inertia side, and the engine (E / G) rotation speed is 180 ° behind the engine (E / G) rotation angular acceleration. As a result of the 90 ° delay in the first order integration, the total delay is 270 °.

  FIG. 15 shows a configuration block diagram of the present embodiment. The apparatus includes a transmission (T / M) gear set value detector 30, a throttle opening detector 32, an engine (E / G) rotation speed detector 31, a bandpass filter circuit 36, a drive shaft (DS) torsional resonance frequency memory. A circuit 39, a vibration frequency detection circuit 40, a throttle opening level determination circuit 42, a throttle opening storage circuit 44, a drive shaft (DS) torsional resonance frequency comparison circuit 47, and a road surface determination circuit 48 are provided.

  The transmission (T / M) gear set value detector 30 detects the gear stage of the transmission (T / M) and outputs it to the road surface determination circuit 48.

  The throttle opening detector 32 detects the throttle opening and outputs it to the vibration frequency detection circuit 40 and the throttle opening level determination circuit 42.

  The engine (E / G) rotational speed detector 31 detects the rotational speed of the engine (E / G) and outputs it to the bandpass filter circuit 36.

  The bandpass filter circuit 36 extracts a specific frequency component from the rotation speed signal of the engine (E / G) and outputs it to the vibration frequency detection circuit 40.

  The vibration frequency detection circuit 40 detects the vibration frequency when the throttle opening changes based on the throttle opening detection signal from the throttle opening detector 32 and the output signal of the bandpass filter circuit 36 to detect the drive shaft (DS). ) Output to the torsional resonance frequency matching circuit 47.

  The drive shaft (DS) torsional resonance frequency storage circuit 39 stores in advance the torsional resonance value of the drive shaft (DS) for each gear stage.

  The drive shaft (DS) torsional resonance frequency check circuit 47 stores the drive shaft (DS) torsional resonance frequency corresponding to the detected gear stage and the vibration frequency detection stored in the drive shaft (DS) torsional resonance frequency storage circuit 39. The vibration frequency detected by the circuit 40 is collated, and it is determined whether or not both are substantially the same.

  The throttle opening level determination circuit 42 compares the detected throttle opening with the throttle opening that is stored in the throttle opening storage circuit 44 and becomes μmax of each road surface, and the result is sent to the road surface determination circuit 48. Output.

  The road surface determination circuit 48 determines and outputs the road surface based on the verification result of the drive shaft (DS) torsional resonance frequency verification circuit 47 and the determination result of the throttle opening level determination circuit 42. That is, the determination result of the throttle opening when the detected vibration frequency substantially coincides with the drive shaft (DS) torsional resonance frequency is output as the road surface determination result.

  FIG. 16 shows a processing flowchart of the present embodiment.

  First, an initial value for performing road surface determination is set (S401). That is, a drive shaft (DS) torsional resonance frequency reference table, a bandpass filter constant, etc. are set for the transmission (T / M) gear stage.

  Next, the gear position is detected by the transmission (T / M) gear set value detector 30 (S402), and the throttle opening is detected by the throttle opening detector 32 (S403).

  The engine (E / G) rotation speed detector 31 detects the engine (E / G) rotation speed (S404), the bandpass filter circuit 36 performs bandpass filtering processing (S405), and the vibration frequency detection circuit 40 Output to.

  The vibration frequency detection circuit 40 determines whether or not the throttle opening has changed based on the detection signal from the throttle opening detector 32 (S406). If the throttle opening has changed, the vibration frequency detection circuit 40 determines from the bandpass filter processing value. The vibration frequency is detected (S407).

  Next, the drive shaft (DS) torsional resonance frequency matching circuit 47 determines whether or not the torsional frequency from the driveshaft (DS) torsional resonance frequency storage circuit 39 and the detected vibration frequency substantially coincide (S408). ), And outputs the determination result to the road surface determination circuit 48.

  On the other hand, the throttle opening level determination circuit 42 compares the detected throttle opening with the throttle opening that is stored in the throttle opening storage circuit 44 and becomes μmax of each road surface, and the result is a road surface determination circuit. 48 (S409).

  The road surface determination circuit 48 determines the road surface using the determination result in the throttle opening level determination circuit 42 when it is determined by the drive shaft (DS) torsional resonance frequency matching circuit 47 to match (S410).

  As described above, the road surface can be determined using the engine (E / G) longitudinal acceleration in the first embodiment, the road surface can be determined using the sprung longitudinal acceleration in the second embodiment, and the drive in the third embodiment. The road surface can be determined using the shaft (DS) torque, and in the fourth embodiment, the road surface can be determined using the engine (E / G) rotational speed or the transmission (T / M) rotational speed. It is possible to determine the road surface by removing the influence of. Further, since physical quantities other than the transmission (T / M) rotation speed are obtained even when the vehicle is stopped, the road surface can be determined even when the vehicle is stopped to start.

  As mentioned above, although embodiment of this invention was described, this invention is not limited to these embodiment, A various deformation | transformation is possible.

  For example, in addition to performing road surface determination using any one of Embodiments 1 to 4 alone, two or more of Embodiments 1 to 4 may be combined to perform road surface determination in combination. . For example, a combination of the first embodiment and the fourth embodiment.

  In the second to fourth embodiments, the vibration frequency may be detected using an FFT circuit instead of the bandpass filter circuit, as in the first embodiment.

  Further, in the first embodiment, the engine (E / G) front / rear resonance frequency storage circuit 38 to the road surface determination circuit 48 are configured by an ECU including one or more processors and a memory, but at least one of these configuration blocks May be mounted as a dedicated hardware circuit (ASIC, FPGA, etc.).

  In this embodiment, the power train (PT) is described as the engine (E / G) and the transmission (T / M). However, the engine (E / G) includes a motor, and the engine (motor And transmission (T / M). When the vehicle is equipped with only a motor, the engine (E / G) may be read as a motor and applied.

10 engine (E / G) block, 12 power train (PT), 14 drive shaft (DS), 16 tires, 18 car body, 20 mount, 30 transmission (T / M) gear set value detector, 32 throttle opening detection , 34 engine (E / G) longitudinal acceleration detector, 36 bandpass filter circuit, 38 engine (E / G) longitudinal resonance frequency memory circuit, 40 vibration frequency detection circuit, 42 throttle opening level judgment circuit, 44 throttle open Degree memory circuit, 46 engine (E / G) front / rear resonance frequency verification circuit, 48 road surface judgment circuit.

Claims (12)

Vibration detection means for detecting vibration components of engine longitudinal resonance;
Detection means for detecting acceleration / deceleration torque;
Storage means for storing a torque reference value up to a friction coefficient μ _max for each road surface;
Determination means for determining a road surface state using the acceleration / deceleration torque and the torque reference value at the time when the vibration component is detected by the vibration detection means;
And the determination means does not determine the road surface state when a predetermined drive shaft torsional resonance frequency corresponding to the current transmission gear stage matches the engine longitudinal resonance frequency. The vibration detection means includes
The road surface determination device according to claim 1, further comprising an engine longitudinal acceleration detection unit configured to detect an engine longitudinal acceleration, wherein the vibration component is detected from the detected longitudinal acceleration of the engine. The detecting means detects a throttle opening as the acceleration / deceleration torque,
The road surface determination device according to claim 2, wherein the determination unit determines the road surface state when the vibration component at the time when the throttle opening changes matches a predetermined engine longitudinal resonance frequency. The vibration detection means includes
The road surface determination device according to claim 1, further comprising a sprung longitudinal acceleration detecting unit that detects a longitudinal acceleration on a spring of the vehicle, and detecting the vibration component from the detected longitudinal acceleration on the spring. The detecting means detects a throttle opening as the acceleration / deceleration torque,
The road surface determination device according to claim 4, wherein the determination unit determines the road surface state when the vibration component at the time when the throttle opening changes matches a predetermined engine longitudinal resonance frequency. Vibration detecting means for detecting a vibration component of drive shaft torsional resonance;
Detection means for detecting acceleration / deceleration torque;
Storage means for storing a torque reference value up to a friction coefficient μ _max for each road surface;
Determination means for determining a road surface state using the acceleration / deceleration torque and the torque reference value at the time when the vibration component is detected by the vibration detection means;
A road surface judging device. The vibration detection means includes
The road surface determination device according to claim 1, further comprising: a torque detection unit configured to detect a torque of the drive shaft, and detecting the vibration component from the detected torque. The detecting means detects a throttle opening as the acceleration / deceleration torque,
The determination unit determines the road surface state when the vibration component at the time when the throttle opening changes matches a predetermined drive shaft torsional resonance frequency corresponding to the current transmission gear stage. The road surface determination apparatus described. The vibration detection means includes
The road surface determination device according to claim 1, further comprising: a rotation speed detection unit that detects a rotation speed of the engine, and detecting the vibration component from the detected rotation speed of the engine. The detecting means detects a throttle opening as the acceleration / deceleration torque,
The determination unit determines the road surface state when the vibration component at the time when the throttle opening changes matches a predetermined drive shaft torsional resonance frequency corresponding to the current transmission gear stage. The road surface determination apparatus described. The vibration detection means further includes
The road surface judging device according to claim 1, further comprising: a band pass filter circuit that extracts a specific frequency component, and detecting the vibration component from an output of the band pass filter circuit. The vibration detection means further includes
The road surface determination device according to claim 1, further comprising: a fast Fourier transform circuit, wherein the vibration component is detected from an output of the fast Fourier transform circuit.