JP2005247068A - Road surface condition detecting system, active suspension system, anti-lock braking system and sensor unit thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a road surface condition detecting system capable of detecting promptly and accurately the road surface when a vehicle is running, an active suspension system and an anti-lock braking system therewith, and a sensor unit thereof. <P>SOLUTION: A sensor unit 100 equipped with an acceleration sensor 100 for detecting the acceleration generated in the rotational direction by rotation of a wheel is provided at a rotor of the wheel rotating mechanical section. A detected acceleration signal is received by a monitor system 200, and information of the road surface condition specified in comparison with a variation pattern of the acceleration signal per road surface previously stored in a storage section 250 are outputted. Based on this road surface condition, drive control by the active suspension system and the anti-lock braking system is carried out. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a road surface state detection system that detects the road surface state by detecting acceleration in the rotational direction of a wheel during vehicle travel, an active suspension system and an anti-lock brake system using the same, and a sensor unit thereof. It is.

  Conventionally, the suspension part of each wheel of the vehicle has been provided with an actuator that can adjust the vehicle body support force to the wheel, etc., and actively adjust the characteristics of the suspension, etc., to change the road surface condition and the load on the vehicle There is known an active suspension system that can keep a vehicle body in a stable state even if a car breaks down.

  Examples of such an active suspension system include, for example, Japanese Patent Application Laid-Open No. 05-185820 (hereinafter referred to as Patent Document 1), Japanese Patent Application Laid-Open No. 08-197931 (hereinafter referred to as Patent Document 2), Japanese Unexamined Patent Publication No. 2000-264034 (hereinafter referred to as Patent Document 3) and the like are known.

  In Patent Document 1, an actuator that is interposed between each wheel of the vehicle and the vehicle body to adjust the force to support the vehicle body with respect to each wheel, and a roll of the vehicle can be suppressed. Distribution setting means for setting the control distribution state of the left wheel side actuator and the right wheel side actuator among the actuators, and control means for controlling the operation of the actuator according to the control distribution state set by the distribution setting means And road surface condition determining means for determining whether the traveling road surface of the vehicle is slippery, and the distribution setting means is determined by the road surface condition determining means to be slippery. An active suspension device for a vehicle is disclosed, which is configured to set a control distribution state capable of reducing the roll suppression of the vehicle. It has been.

  Patent Document 2 discloses an active suspension device in which an electromagnetic actuator including a screw means having a male screw member and a female screw member that mesh with each other and a motor that drives the screw means to extend and contract is disposed between a wheel and a vehicle body. An active suspension device is disclosed, wherein at least one of the motor or the screw means is elastically supported on at least one of a wheel or a vehicle body via a spring means.

  Further, in Patent Document 3, a hydraulic cylinder interposed between a wheel and a vehicle body and provided in parallel with a suspension spring, a hydraulic pump and a tank connected to the hydraulic cylinder, and a flow rate or a pressure of the hydraulic cylinder are commanded. A control valve controlled according to the value, a detection means for detecting the longitudinal and lateral accelerations of the vehicle, a vehicle speed, etc., a controller for calculating a detection value of the detection means and outputting a control signal, and a control signal of the controller In the active suspension control device comprising the hydraulic pump and the driver for driving the control valve, the hydraulic cylinder that is extended and contracted through the hydraulic pump by the output of the driver is configured as a double-acting type divided into upper and lower chambers Similarly, the hydraulic pump whose discharge direction and start and stop are controlled by the output of the driver is configured as a forward / reverse type, and the control valve is connected to the hydraulic cylinder. It consists of a pair of electromagnetic proportional pressure control valves provided in the return passage from the upper and lower chambers to the tank. The driver, hydraulic pump, hydraulic cylinder, and electromagnetic proportional pressure control valve are arranged independently for each wheel. The electromagnetic proportional pressure control valve controls the pressure in the upper and lower chambers of the hydraulic cylinder to generate a control force that suppresses expansion and contraction of the hydraulic cylinder, and further discharges oil from the hydraulic pump controlled by the output of the driver. A control device for an active suspension is disclosed in which the attitude of a vehicle is controlled by selectively supplying the pressure to one of the upper and lower chambers of the hydraulic cylinder via a check valve.

  Also, an example of an active suspension system that stabilizes seats in the vehicle body during vehicle travel and improves riding comfort is disclosed in Japanese Patent Laid-Open No. 10-203221 (hereinafter referred to as Patent Document 4). Yes.

  On the other hand, matters to be noted in order to perform safe driving in the vehicle include setting the air pressure in the tire of the vehicle to an appropriate state and paying attention to the wear state of the tire. For example, when the air pressure in the tire decreases, the occurrence rate of punctures increases and bursts occur at high speeds, causing a serious accident. For this reason, the driver needs to check the tires on a regular basis.

  However, when the tires are inspected and the tires are kept in good condition, the brakes are applied when the frictional force between the road surface and the tire decreases, such as when the road surface is wet during rainy weather. Slip into the car and the vehicle may move in an unexpected direction, causing an accident.

  In order to prevent accidents caused by such slips and sudden starts, an anti-lock brake system (hereinafter referred to as ABS), a traction control system, and in addition to these A stability control system equipped with a YAW sensor has been developed.

  For example, ABS is a system that detects the rotational state of each tire and controls the braking force so as to prevent each tire from entering a locked state based on the detection result.

  As the rotation state of the tire, it is possible to detect the number of rotations of each tire, the state of air pressure, distortion, and the like, and use this detection result for control.

  Examples of such a control system include, for example, an automobile brake device disclosed in Japanese Patent Laid-Open No. 05-338528 (hereinafter referred to as Patent Document 5), and brake control disclosed in Japanese Patent Laid-Open No. 2001-018775. Device (hereinafter referred to as Patent Document 6), vehicle control method and apparatus disclosed in JP 2001-182578 A (hereinafter referred to as Patent Document 7), vehicle disclosed in JP 2002-137721 A A motion control device (hereinafter referred to as Patent Document 8), a brake device disclosed in JP 2002-160616 A (hereinafter referred to as Patent Document 9), and the like are known.

  In Patent Document 5, negative pressure is supplied from a vacuum tank to a vacuum booster connected to a brake pedal, and negative pressure is supplied from a vacuum pump to the vacuum tank, and the vacuum pump is driven by a pump motor. When the acceleration sensor 14 detects that the deceleration acceleration of the vehicle has reached a predetermined value, the pump motor for operating the vacuum pump is controlled so that the operation fee at the time of a sudden brake operation and the brake operation immediately thereafter is controlled. A brake device for preventing ring changes is disclosed.

  In Patent Literature 6, in a brake control device including a control unit that executes ABS control, a lateral acceleration estimation unit that estimates a lateral acceleration generated in a vehicle and an estimation by the lateral acceleration estimation unit are included in the control unit. The lateral acceleration, the estimated lateral acceleration by the vehicle behavior detecting means, and the detected lateral acceleration detected by the lateral acceleration sensor included in the vehicle behavior detecting means are compared, and if the difference between the two is less than a predetermined value, the steering angle is met. Comparing and determining means for determining that the vehicle is turning normally and determining that the vehicle is turning abnormally if the difference is greater than or equal to a predetermined value is provided. Discloses a brake control device that switches control.

  Patent Document 7 discloses a vehicle acceleration or vehicle deceleration generated by a traveling road surface inclination in a vehicle control method and apparatus in which a control signal for adjusting vehicle deceleration and / or acceleration is formed by a corresponding set value. A vehicle control method and apparatus are disclosed that improve the vehicle deceleration and / or acceleration settings by forming a correction factor representative of

In Patent Document 8, the lateral slip angle change speed β ′ of the center of gravity is obtained as the actual yawing motion state quantity of the vehicle having a plurality of wheels, and the absolute value of the change speed β ′ is greater than or equal to the set value β ₀ ′. For example, by applying the brake fluid pressure ΔP to one of the left and right rear brakes, the larger the value of the change speed β ′, the larger the value and the smaller the value of the change speed β ′. During the yawing moment control, it is determined whether or not the slip control is necessary for the wheel to which the brake fluid pressure ΔP is applied. If the slip control is necessary, the brake fluid pressure A vehicle motion control device that performs slip control that keeps the slip ratio within an appropriate range by suppressing ΔP is disclosed.

  Patent Document 9 includes at least two of an acceleration sensor that detects acceleration in the vehicle longitudinal direction, a wheel speed sensor that detects wheel speed of each wheel, and a brake pressure sensor that detects brake pressure. The target brake pressure is calculated by feedback from at least two sensors, and based on the calculation result, the command current is calculated by the command current calculation unit, and the command current is supplied to the brake drive actuator to obtain the magnitude of the command current. A brake device is disclosed that can suppress an output abnormality even if a disturbance occurs or one sensor breaks down by generating a corresponding braking force.

Further, as a method for detecting the rotation speed of the tire, as shown in FIGS. 37 and 38, a method of detecting the rotation speed of the tire by a rotor 1 and a pickup sensor 2 that rotate integrally with a wheel carrier is common. is there. In this method, a plurality of irregularities provided at equal intervals on the circumferential surface of the rotor 1 crosses the magnetic field generated by the pickup sensor 2 to change the magnetic flux density, and a pulsed voltage is applied to the coil of the pickup sensor 2. Occur. The number of rotations can be detected by detecting this pulse. An example of the basic principle of this method is disclosed in Japanese Patent Laid-Open No. 52-109981.
Japanese Patent Laid-Open No. 05-185820 JP 08-197931 A JP 2000-264034 A Japanese Patent Laid-Open No. 10-203221 Japanese Patent Laid-Open No. 05-338528 JP 2001-018775 A Japanese Patent Laid-Open No. 2001-182578 JP 2002-137721 A Japanese Patent Laid-Open No. 2002-160616 JP 52-109981 A

  One of the reasons for requiring the active suspension system and the anti-lock brake system as described above is a change in the state of the road surface on which the vehicle travels. When the road surface condition changes depending on the weather and the environment, the vibration of the vehicle body and the stability decrease, and further, the change of the braking effect and the slip of the wheel at the time of the brake operation occur. For this reason, technology development for quickly and accurately detecting the road surface state is being performed.

  In view of the above problems, an object of the present invention is a road surface state detection system capable of quickly and accurately detecting a road surface state during vehicle travel, an active suspension system, an anti-lock brake system using the same, and a sensor unit thereof. Is to provide.

  In order to achieve the above-mentioned object, the present invention is provided in a rotating mechanism portion including a rotating body that is provided on a vehicle body of a vehicle and rotates the wheel by fixing the wheel, and in a rotating direction along with the rotation. A sensor unit that detects the generated acceleration and converts it into an electrical signal, converts the detected acceleration signal into digital data, and transmits digital information including the digital data, and is provided in the vehicle body and is transmitted from the sensor unit. A monitor device that receives the digital information and obtains the acceleration signal, and the monitor device provides information on the fluctuation characteristics of the acceleration signal detected for each road surface state on which the vehicle travels. A plurality of types of road surface state storage means corresponding to information, acceleration signals received from the sensor unit, and road surface state storage means are recorded. The road surface state specifying means for specifying the road surface state corresponding to the received acceleration signal and the information on the road surface state specified by the road surface state specifying means based on the information on the fluctuation characteristics of the acceleration signal that is received. A road surface state detection system having road surface state information output means for extracting and outputting from a state storage means is proposed.

  According to the present invention, the acceleration in the rotational direction of the wheel during traveling of the vehicle is detected by the sensor unit, and the electrical signal of the acceleration is received by the monitor device as digital information. Further, in the monitor device, the road surface state corresponding to the received acceleration signal is specified based on the received acceleration signal and information on the fluctuation characteristics of the acceleration signal stored in the road surface state storage means, and the specified road surface Status information is output.

  Further, in the present invention, the acceleration characteristic variation characteristic pattern is stored in the road surface storage means as information relating to the variation characteristic of the acceleration signal in the wheel rotation direction, and the monitor device receives the variation characteristic pattern of the acceleration signal and the received acceleration. The road surface condition is specified by comparing the signal.

  Alternatively, in the present invention, information obtained by performing predetermined processing on the fluctuation characteristics of the acceleration signal is stored in the road surface storage means as information on the fluctuation characteristics of the acceleration signal in the wheel rotation direction, and the monitor device Specifies the road surface state based on the information obtained by performing this processing and the received acceleration signal.

  Moreover, in this invention, the acceleration of the rotation direction of a wheel is detected by providing a sensor unit in the said rotary body.

  In the present invention, the sensor unit is operated by the means for receiving the electromagnetic wave of the first frequency, the means for converting the received electromagnetic wave energy of the first frequency into electric energy for driving, and the electric energy. And means for transmitting the digital information using an electromagnetic wave having a second frequency, wherein the monitor device radiates the electromagnetic wave having the first frequency, and means for receiving the electromagnetic wave having the second frequency. And means for extracting the digital information from the received electromagnetic wave of the second frequency.

  With the above configuration, the sensor unit operates by the energy of the first frequency electromagnetic wave received from the monitor device and transmits the digital data of the acceleration signal to the monitor device by the second frequency electromagnetic wave. Communication between them can be performed wirelessly. Furthermore, it is not necessary to provide a power source such as a battery in the sensor unit.

  In the present invention, the first frequency and the second frequency are set to the same frequency, and transmission and reception are performed in a time division manner.

  Further, the present invention provides a rotation mechanism in which a sensor unit is provided with means for transmitting identification information unique to itself to the monitor device and transmitted to the monitor device, and the sensor device is provided by the identification information received from the sensor unit by the monitor device. The part can be identified.

  In the present invention, the sensor unit includes a semiconductor acceleration sensor having a silicon piezo-type diaphragm in order to detect acceleration in the rotational direction of the wheel.

  Furthermore, in the present invention, the road surface state detection system having the above-described configuration is applied to an active suspension system so that suspension control can be performed quickly corresponding to the road surface state during vehicle travel.

  Further, according to the present invention, the road surface state detection system having the above-described configuration is applied to an anti-lock brake system so that the brake control can be quickly performed in response to the road surface state during vehicle travel.

  Further, in order to achieve the above object, the present invention is provided in a rotating mechanism portion that is provided on the vehicle body side and includes a rotating body that fixes a wheel and rotates the wheel, and the wheel, and is generated with rotation. A sensor unit for detecting acceleration, comprising: means for detecting acceleration generated in the rotational direction with rotation and converting it into an electrical signal; means for converting the acceleration signal into digital data; and a digital including the digital data A sensor unit comprising means for transmitting information is proposed.

  According to the sensor unit having the above-described configuration, the acceleration generated in the rotation direction with the rotation of the wheel is detected and converted into an electrical signal, and the acceleration signal is converted into digital data. Digital information including the digital data Is sent.

  Here, since the position of the sensor unit moves with the number of rotations in the rotation mechanism unit and the combined value of the acceleration in the vehicle traveling direction and the acceleration in the rotation direction of the wheels applied to the sensor unit changes, The electrical signal of the acceleration in the wheel rotation direction fluctuates in a sine wave shape with the rotation. Further, the cycle of this fluctuation becomes shorter as the rotational speed increases, and the magnitude and cycle of the fluctuation change according to the road surface condition. Therefore, it is possible to detect the rotation speed of the wheel per unit time and the road surface state from the acceleration signal.

  According to the road surface condition detection system of the present invention, the fluctuation period of the detected electrical signal of the acceleration in the wheel rotation direction when the vehicle is running is shortened as the number of rotations is increased, and the magnitude and period of the fluctuation are varied according to the road surface condition. Since it changes, it becomes possible to quickly detect the road surface state from the acceleration signal.

  Therefore, the active suspension system to which the road surface condition detection system of the present invention is applied can perform suspension control in response to the road surface condition during vehicle travel.

  Moreover, the anti-lock brake system to which the road surface condition detection system of the present invention is applied can perform brake control in response to the road surface condition when the vehicle is running.

  Furthermore, according to the sensor unit of the present invention, it is possible to easily detect the acceleration in the rotational direction caused by the rotation of the wheel only by providing the sensor unit at a predetermined position of the rim, the wheel, the wheel such as the tire body, and the rotating body such as the axle. can do.

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

  FIG. 1 is a block diagram showing an electric circuit of the road surface condition detection system according to the first embodiment of the present invention. The road surface condition detection system in the present embodiment includes a sensor unit 100 and a monitor device 200.

  As shown in FIG. 1, the electrical system circuit of the monitor device 200 includes a radiation unit 210, a wave receiving unit 220, a control unit 230, a calculation unit 240, and a storage unit 250. Here, the control unit 230 and the calculation unit 240 are configured by a memory circuit including a known CPU, a ROM storing a program for operating the CPU, a RAM necessary for performing calculation processing, and the like.

  The radiation unit 210 includes an antenna 211 and a transmission unit 212 for radiating electromagnetic waves having a predetermined frequency (first frequency) in the 2.45 GHz band. Based on an instruction from the control unit 230, the radiation unit 210 performs the above-described operation from the antenna 211. Radiates electromagnetic waves of one frequency.

  As an example of the transmission unit 212, a configuration including an oscillation circuit 161, a modulation circuit 162, and a high-frequency amplification circuit 163 can be given, similarly to the transmission unit 160 of the sensor unit 100. As a result, an electromagnetic wave of 2.45 GHz is radiated from the antenna 211. The high frequency power output from the transmitter 212 is set to a value that can supply electric energy to the sensor unit 100 from the electromagnetic wave radiation antenna 211 of the monitor device 200. Accordingly, the acceleration 320 of each tire 300 can be detected for each monitor device 200.

  The wave receiving unit 220 includes an antenna 221 for receiving an electromagnetic wave having a predetermined frequency (second frequency) in the 2.45 GHz band and a detection unit 222. Based on an instruction from the control unit 230, the antenna 221 The received electromagnetic wave of the second frequency is detected, and the signal obtained by the detection is converted into a digital signal and output to the arithmetic unit 250. As an example of the detection unit 222, a circuit similar to the detection unit 150 of the sensor unit 100 described later can be cited.

  When the operation starts, the control unit 230 drives the transmission unit 212 to radiate electromagnetic waves for a predetermined time t3, and then drives the detection unit 222 for a predetermined time t4, from the detection unit 222 to the calculation unit 240. To output a digital signal.

  The arithmetic unit 240 detects accelerations in directions orthogonal to each other including acceleration in the wheel rotation direction transmitted from the sensor unit 100 based on the digital signal, and the acceleration in the wheel rotation direction is stored in the storage unit 250. A road surface state is specified based on the road surface state information, and information on the specified road surface state and detected values of three accelerations are output. Thereafter, the control unit 230 repeats the same processing as described above.

  The storage unit 250 includes a plurality of types of information regarding the fluctuation characteristics of the acceleration signal in the rotational direction of the wheel detected by the sensor unit 100 for each state of the road surface on which the vehicle travels corresponding to the road surface state information, as will be described later. It is remembered. These pieces of information are obtained in advance by performing a test run of the vehicle. In the present embodiment, the storage unit 250 stores a variation characteristic pattern of an acceleration signal generated in the wheel rotation direction as information on the variation characteristic of the acceleration signal. Note that information obtained by performing a predetermined processing on the variation characteristic of the acceleration signal may be stored as information regarding the variation characteristic of the acceleration signal in the wheel rotation direction. For example, the noise component information corresponding to the road surface state obtained by mixing the anti-phase component of the acceleration component with the acceleration signal in advance and removing the acceleration component is stored in the storage unit 250 in advance. The road surface condition may be determined based on information on noise components obtained by performing the same processing as described above on the acquired acceleration signal and information stored in the storage unit 250. Alternatively, as information obtained by performing the processing, information obtained by integrating the noise component of the acceleration signal, for example, a voltage value obtained by integrating the noise component may be used.

  In the present embodiment, the radiation time t3 in the monitor device 200 is set to 0.15 ms, and the reception time t4 is set to 0.85 ms. Thereby, the monitor apparatus 200 can acquire an acceleration signal from the sensor unit 100 every 1 ms, and can acquire an acceleration signal in a state close to an analog signal. In the present embodiment, electromagnetic waves are radiated from the radiating unit 210 for a time t3 so that a voltage of 3 V or more can be stored as electric energy sufficient to drive the sensor unit 100.

  As shown in FIG. 2, the sensor unit 100 and the monitor device 200 are fixed to the rotation mechanism portion of the tire 300 of the vehicle, and the monitor device 200 is fixed to the tire house 3 of the tire 300. ing.

  As shown in FIG. 3, the rotation mechanism unit 500 provided with the sensor unit 100 includes a brake disc 520 that rotates together with the axle 510, a wheel carrier 530 for fixing the wheel of the tire 300, and a tire body and rim in the tire 300. Including rotating bodies.

  In the present embodiment, the sensor unit 100 is fixed to a predetermined position of a brake disk 520 that rotates together with the tire 300 as shown in FIGS. 2 and 3, for example, and will be described later. Acceleration in three directions perpendicular to each other caused by rotation of the tire 300 is detected by the acceleration sensor that converts the acceleration signal into an electrical signal, and the acceleration signal is converted into digital data. Further, digital information including digital data of the acceleration signal as a detection result is generated and transmitted.

  In this embodiment, the sensor unit 100 is fixed to the brake disk 520, but the present invention is not limited to this. For example, as shown in FIG. In FIG. 4, a tire 300 is, for example, a well-known tubeless radial tire, and includes a wheel and a rim in this embodiment. 3 and 4, reference numeral 300 denotes a tire, which includes a tire body 305, a rim 306, and a wheel (not shown). The tire body 305 includes a well-known cap tread 301, under tread 302, belts 303A and 303B, carcass 304. Etc.

  Further, the number of sensor units 100 provided in each rotation mechanism unit 500 is not limited to one, and two or more sensor units 100 may be provided for assistance.

  A specific example of the electrical circuit of the sensor unit 100 is the circuit shown in FIG. That is, in one specific example shown in FIG. 5, the sensor unit 100 includes an antenna 110, an antenna switch 120, a rectifier circuit 130, a central processing unit 140, a detection unit 150, a transmission unit 160, and a sensor unit 170. .

  The antenna 110 is for communicating with the monitor device 200 using electromagnetic waves, and is matched to a predetermined frequency (first frequency) in the 2.4 GHz band, for example.

  The antenna switch 120 is configured by an electronic switch, for example, and switches between connection of the antenna 110, the rectifier circuit 130 and the detection unit 150, and connection of the antenna 110 and the transmission unit 160 under the control of the central processing unit 140.

  The rectifier circuit 130 includes diodes 131 and 132, a capacitor 133, and a resistor 134, and forms a known full-wave rectifier circuit. An antenna 110 is connected to the input side of the rectifier circuit 130 via an antenna switch 120. The rectifier circuit 130 rectifies the high-frequency current induced in the antenna 110 and converts it into a direct current, and outputs this as a drive power source for the central processing unit 140, the detection unit 150, the transmission unit 160, and the sensor unit 170.

  The central processing unit 140 includes a well-known CPU 141, a digital / analog (hereinafter referred to as D / A) conversion circuit 142, and a storage unit 143.

  The CPU 141 operates based on a program stored in the semiconductor memory of the storage unit 143, and when supplied with electric energy and driven, digital information including digital data of an acceleration signal acquired from the sensor unit 170 and identification information described later. And processing for transmitting this digital information to the monitor device 200 is performed. The storage unit 143 stores the identification information unique to the sensor unit 100 in advance.

  The storage unit 143 includes a ROM in which a program for operating the CPU 141 is recorded and an electrically rewritable nonvolatile semiconductor memory such as an EEPROM (electrically erasable programmable read-only memory). The unique identification information is stored in advance in an area designated as non-rewritable in the storage unit 143 at the time of manufacture.

  The detection unit 150 includes a diode 151 and an A / D converter 152, the anode of the diode 151 is connected to the antenna 110, and the cathode is connected to the CPU 141 of the central processing unit 140 via the A / D converter 152. . Thus, the electromagnetic wave received by the antenna 110 is detected by the detection unit 150, and the signal obtained by the detection is converted into a digital signal and input to the CPU 141.

  The transmission unit 160 includes an oscillation circuit 161, a modulation circuit 162, and a high-frequency amplification circuit 163. The transmission unit 160 is configured using a known PLL circuit or the like and performs central processing on a carrier wave having a frequency of 2.45 GHz band oscillated by the oscillation circuit 161. Based on the information signal input from the unit 140, the signal is modulated by the modulation circuit 162 and supplied to the antenna 110 through the high frequency amplifier circuit 163 and the antenna switch 120 as a high frequency current of a 2.45 GHz band frequency (second frequency). To do. In this embodiment, the same frequency as the first frequency and the second frequency is set, but the first frequency and the second frequency may be different frequencies.

  The sensor unit 170 includes the acceleration sensor 10 and an A / D conversion circuit 171.

  The acceleration sensor 10 is composed of a semiconductor acceleration sensor as shown in FIGS.

  6 is an external perspective view showing the semiconductor acceleration sensor according to the first embodiment of the present invention, FIG. 7 is a sectional view taken along line BB in FIG. 6, and FIG. 8 is a sectional view taken along line CC in FIG. 9 and 9 are exploded perspective views.

  In the figure, reference numeral 10 denotes a semiconductor acceleration sensor, which comprises a pedestal 11, a silicon substrate 12, and supports 19A and 19B.

  The base 11 has a rectangular frame shape, and a silicon substrate (silicon wafer) 12 is attached to one opening surface of the base 11. Further, the outer frame portion 191 of the supports 19a and 19B is fixed to the outer peripheral portion of the base 11.

  A silicon substrate 12 is provided at the opening of the pedestal 11, a thin film diaphragm 13 having a cross shape is formed at the center of the wafer outer peripheral frame 12a, and piezoresistors are formed on the upper surfaces of the diaphragm pieces 13a to 13d. (Diffusion resistors) Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4 are formed.

  Specifically, one of the diaphragm pieces 13a and 13b arranged on a straight line is formed with a piezoresistor Rx1, Rx2, Rz1, and Rz2 and the other diaphragm piece 13b is formed with a piezoresistor Rx3. , Rx4, Rz3, and Rz4 are formed. Piezoresistors Ry1 and Ry2 are formed on one of the diaphragm pieces 13c and 13d arranged on a straight line orthogonal to the diaphragm pieces 13a and 13b, and the piezoresistor is formed on the other diaphragm piece 13d. The bodies Ry3 and Ry4 are formed. Further, these piezoresistors Rx1 to Rx4, Ry1 to Ry4, and Rz1 to Rz4 can configure a resistance bridge circuit for detecting acceleration in the X axis, Y axis, and Z axis directions orthogonal to each other. And connected to a connection electrode 191 provided on the outer peripheral surface of the silicon substrate 12.

  Further, a thick film portion 14 is formed on one surface side of the central portion of the diaphragm 13 at the intersection of the diaphragm pieces 13a to 13d, and the surface of the thick film portion 14 has a rectangular parallelepiped shape made of, for example, glass. A weight 15 is attached.

  On the other hand, the support members 19A and 19B are provided so as to connect an outer frame portion 191 having a rectangular frame shape, four support columns 192 erected at the four corners of the fixed portion, and tip portions of the support columns. A cross-shaped beam portion 193 and a conical projection portion 194 provided at the central intersection of the beam portion 193.

  The outer frame portion 191 is fitted and fixed to the outer peripheral portion of the pedestal 11 so that the protruding portion 194 is positioned on the other surface side of the diaphragm 13, that is, on the side where the weight 15 does not exist. Here, the tip 194a of the protrusion 194 is set so as to be located at a distance D1 from the surface of the diaphragm 13 or the weight 15. This distance D1 causes the diaphragm pieces 13a to 13d to extend even when acceleration occurs in a direction perpendicular to the surface of the diaphragm 13 and a force of a predetermined value or more is applied to both surfaces of the diaphragm 13 due to this acceleration. The displacement is set to a value that can be limited by the projection 194 so as not to occur.

  When the semiconductor acceleration sensor 10 having the above configuration is used, three resistance bridge circuits are configured as shown in FIGS. That is, as a bridge circuit for detecting the acceleration in the X-axis direction, as shown in FIG. 11, the positive electrode of the DC power supply 32A is connected to the connection point between one end of the piezoresistor Rx1 and one end of the piezoresistor Rx2. The negative electrode of the DC power supply 32A is connected to the connection point between one end of the piezoresistor Rx3 and one end of the piezoresistor Rx4. Further, one end of the voltage detector 31A is connected to the connection point between the other end of the piezoresistor Rx1 and the other end of the piezoresistor Rx4, and the other end of the piezoresistor Rx2 and the other end of the piezoresistor Rx3 are connected. The other end of the voltage detector 31A is connected to the point.

  As a bridge circuit for detecting the acceleration in the Y-axis direction, as shown in FIG. 12, the positive electrode of the DC power supply 32B is connected to the connection point between one end of the piezoresistor Ry1 and one end of the piezoresistor Ry2. The negative electrode of the DC power supply 32B is connected to the connection point between one end of the piezoresistor Ry3 and one end of the piezoresistor Ry4. Further, one end of the voltage detector 31B is connected to the connection point between the other end of the piezoresistor Ry1 and the other end of the piezoresistor Ry4, and the connection between the other end of the piezoresistor Ry2 and the other end of the piezoresistor Ry3. The other end of the voltage detector 31B is connected to the point.

  As a bridge circuit for detecting acceleration in the Z-axis direction, as shown in FIG. 13, the positive electrode of the DC power supply 32C is connected to the connection point between one end of the piezoresistor Rz1 and one end of the piezoresistor Rz2. The negative electrode of the DC power source 32C is connected to the connection point between one end of the piezoresistor Rz3 and one end of the piezoresistor Rz4. Further, one end of the voltage detector 31C is connected to a connection point between the other end of the piezoresistor Rz1 and the other end of the piezoresistor Rz3, and a connection between the other end of the piezoresistor Rz2 and the other end of the piezoresistor Rz4. The other end of the voltage detector 31C is connected to the point.

  According to the semiconductor acceleration sensor 10 having the above-described configuration, when the force generated along with the acceleration applied to the sensor 10 is applied to the weight 15, the diaphragm pieces 13a to 13d are distorted, thereby causing the piezoresistors Rx1 to Rx4, The resistance values of Ry1 to Ry4 and Rz1 to Rz4 change. Accordingly, by forming a resistance bridge circuit by the piezoresistors Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4 provided on the diaphragm pieces 13a to 13d, accelerations in the X axis, Y axis, and Z axis directions orthogonal to each other are formed. Can be detected.

  Further, as shown in FIGS. 14 and 15, when acceleration is applied such that forces 41 and 42 including force components in a direction perpendicular to the surface of the diaphragm 13 are applied, a predetermined value is applied to the other surface side of the diaphragm 13. When the above force is applied, the diaphragm 13 is distorted and stretched in the direction in which the forces 41 and 42 are applied, but the displacement is supported and limited by the apex 194a of the protrusion 194, so that each of the diaphragm pieces 13a to 13d is maximum. There is no limit. Thereby, even when a force of a predetermined value or more is applied to the other surface side of the diaphragm 13, the position of the weight 15 is displaced with the vertex 194 a of the projection 194 serving as a fulcrum, so that it is parallel to the surface of the diaphragm 13. Acceleration in any direction can be detected.

  As shown in FIG. 16, when the vehicle is running with the tire 300 rotated by the semiconductor acceleration sensor 10, the X, Y, and Z axis directions perpendicular to each other generated with the rotation of the tire 300. Can be detected. Here, the sensor unit 100 is provided such that the X axis corresponds to the rotation direction of the tire 300, Y corresponds to the rotation axis direction, and the Z axis corresponds to the direction orthogonal to the rotation axis.

  On the other hand, the A / D conversion circuit 171 converts the analog electrical signal output from the acceleration sensor 10 into a digital signal and outputs the digital signal to the CPU 141. This digital signal corresponds to the acceleration values in the X, Y, and Z axis directions.

  In addition, as the acceleration generated in the X, Y, and Z axis directions, there are a positive acceleration and a negative acceleration. In the present embodiment, both accelerations can be detected.

  Further, as will be described later, it is also possible to obtain the rotational speed of the wheel from the acceleration in the X-axis direction. The central processing unit 140 of the sensor unit 100 calculates the rotational speed of the wheel per unit time, and the calculation result It is also possible to transmit the digital value included in the digital information.

  Further, in the present embodiment, as described above, the frequency of the 2.45 GHz band is used as the first and second frequencies, thereby being affected by the belts 303A and 303B in which metal wires for reinforcing the tire 300 are woven. Therefore, even if the sensor unit 100 is fixed to the rim 306, stable communication can be performed. Thus, in order to make it difficult to be affected by the metal in the tire such as a reinforcing metal wire, it is preferable to use a frequency of 1 GHz or more as the first and second frequencies.

  It is also possible to embed the sensor unit 100 in the tire 300 at the time of manufacturing the tire 300. In this case, the IC chip and other components are designed to withstand the heat during vulcanization. Needless to say that it is.

  Next, the operation of the system configured as described above will be described with reference to FIGS. FIGS. 17 to 19 are actual measurement results of acceleration in the Z-axis direction, FIGS. 20 to 22 are actual measurement results of acceleration in the X-axis direction, FIGS. 23 and 24 are actual measurement results of acceleration in the Y-axis direction, and FIG. The actual measurement result of the acceleration in the X-axis direction when applied, and FIG. 26 show the actual measurement result of the acceleration in the Z-axis direction when the brake is applied.

  17 to 19, FIG. 17 is an actual measurement value of acceleration in the Z-axis direction when traveling at a speed of 2.5 km, FIG. 18 is an actual measurement value of acceleration in the Z-axis direction when traveling at a speed of 20 km / hour, and FIG. This is an actual measurement value of acceleration in the Z-axis direction when traveling at a speed of 40 km / h. Thus, since the centrifugal force of the wheel increases as the traveling speed increases, the acceleration in the Z-axis direction also increases. Therefore, the traveling speed can be obtained from the acceleration in the Z-axis direction. In the figure, the measured value has a sine wave shape because it is influenced by gravitational acceleration.

  20 to 22, FIG. 20 is an actual measurement value of acceleration in the X-axis direction when traveling at a speed of 2.5 km, FIG. 18 is an actual measurement value of acceleration in the X-axis direction when traveling at a speed of 20 km, and FIG. This is an actual measurement value of acceleration in the X-axis direction when traveling at a speed of 40 km / h. Thus, since the rotation speed of the wheel increases as the traveling speed increases, the cycle in which the acceleration in the X-axis direction changes becomes shorter. Therefore, it is possible to obtain the rotational speed of the wheel from the acceleration in the X-axis direction. In the figure, the reason why the actually measured value has a sine wave shape is that it is affected by the gravitational acceleration as described above.

  FIG. 23 shows measured values of acceleration in the Y-axis direction when the steering wheel is turned to the right during traveling, and FIG. 24 shows measured values of acceleration in the Y-axis direction when the steering wheel is turned to the left during traveling. Thus, when the steering wheel is turned and the wheel is swung left and right, the acceleration in the Y-axis direction appears significantly. Needless to say, the acceleration in the Y-axis direction is similarly generated when the vehicle body slides. The reason why the reverse acceleration occurs in the actual measured values of the acceleration in the Y-axis direction is that the driver unconsciously turns the steering wheel slightly in the reverse direction.

  25 and 26, it is also accurate that the time from when the brake is applied (when the brake is on: when the brake pedal is depressed) to when the wheel stops rotating is about 0.2 seconds. Could be detected.

  By detecting the acceleration generated when the brake pedal 610 is depressed in this way, it is possible to estimate the amount of distortion of the tire 300 caused by this acceleration, the side slip state of the vehicle body, the idling state of the tire, and the like. Thus, the pressure control valve during vehicle braking can be controlled.

  Further, the state of the acceleration signal in the X-axis direction (acceleration in the wheel rotation direction) changes depending on the road surface state during vehicle travel. For example, FIGS. 27 to 29 each record changes in the acceleration signal in the X-axis direction (wheel rotation direction) when traveling at a vehicle traveling speed of 60 km / h. However, FIG. 27 shows a change in acceleration signal on a dry paved road during fine weather, and FIG. 28 shows a change in acceleration signal on a paved road with a water film having a depth of 2 to 3 mm in rainy weather. FIG. 29 shows a recorded change in acceleration signal on a paved road (including a snow-capped road) where the entire surface of the road surface is frozen.

  As shown in FIG. 27, on the dry paved road in fine weather, the amplitude and period of the acceleration signal in the X-axis direction are substantially constant. Further, as shown in FIG. 28, on a paved road where the road surface is covered with a water film having a depth of 2 to 3 mm during rainy weather, the tire may slip due to the water film, so the amplitude of the acceleration signal in the X-axis direction and Disturbance occurs in the cycle. In addition, as shown in FIG. 29, on a paved road (including a snowy road) whose surface is frozen, tires are always slipping, so the amplitude of the acceleration signal in the X-axis direction is a dry paved road when the weather is clear. Compared to, the period is also increased.

  Since the state of the acceleration signal in the X-axis direction clearly changes depending on the road surface in this way, in this embodiment, the change pattern of the acceleration signal in the X-axis direction at a plurality of traveling speeds in various road surface states is measured in advance. This is stored in the storage unit 250.

  Therefore, the calculation unit 240 of the monitor device 200 identifies the road surface state based on the acceleration signal in the wheel rotation direction (X-axis direction) received from the sensor unit 100 and the road surface state information stored in the storage unit 250. Information on the identified road surface condition can be output. Thus, in this embodiment, the state of the traveling road surface can be detected quickly and accurately based on the acceleration signal in the X-axis direction.

  Next, a second embodiment of the present invention will be described. In the second embodiment, an active suspension system to which the aforementioned road surface information detection system is applied will be described.

  FIG. 30 is a schematic configuration diagram showing an active suspension system according to the second embodiment of the present invention, and FIG. 31 is a configuration diagram showing a suspension main body according to the second embodiment. In the figure, the same components as those of the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

In the figure, 100 is a sensor unit, 200 is a monitoring device, 300 is a tire, 410
Is a suspension drive source, 420 is a suspension body, and 450 is a suspension drive control unit.

  The monitor device 200 is fixed to each tire house in the same manner as described above, and each monitor device 200 is connected to the suspension drive control unit 450 by a cable, operates by the electric energy sent from the suspension drive control unit 450, and detects the road surface Information on the state is sent to the suspension drive control unit 450.

  The suspension drive control unit 450 is configured mainly with a well-known CPU, takes in road surface state information output from each monitor device 200, and performs drive control of the suspension drive source 410 based on these information.

  The suspension drive source 410 is configured mainly with a known hydraulic pump, and controls the hydraulic pressure in the damper of the suspension body 420 based on an electrical signal from the suspension drive control unit 450.

  As shown in FIG. 31, the suspension main body 420 includes an upper mount portion 421 for absorbing a change in the angle of the damper 425 with respect to the vehicle body, a spring upper seat 422, a coil spring 423, a rubber member 424, a hydraulic damper 425, And a damper connecting member 426.

  The upper surface of the suspension body 420 is connected to a vehicle body (not shown), and a spring upper seat 422 is attached to the bottom surface of the upper mount portion 421. In addition, a coil spring 423 is mounted between the spring upper sheet 422 and an annular tray-shaped guide 433 provided on the cylindrical damper 425.

  In this state, the piston rod 432 of the damper 425 is positioned substantially at the central axis of the coil spring 423, and an annular bracket provided so as to protrude radially to the tip of the piston rod 432 is an upper mount portion 421. It touches the bottom of the. A substantially cylindrical rubber member 424 is provided so as to be positioned between the piston rod 432 and the coil spring 423.

  The piston rod 432 of the damper 425 is inserted into the outer cylinder 431 from its upper end, and the amount of the piston rod 432 inserted into the outer cylinder 431 according to the pressure of the oil filled in the outer cylinder 431 and the force applied from the outside is As a result, the length of the damper 425 itself changes.

  The lower end of the damper 425 is fixed to a damper connecting member 426. The damper connecting member 426 is connected to the hub carrier 440, and the axle is supported by the hub carrier 440 as shown in FIG. Further, the hub carrier 440 is connected to a vehicle body (not shown) via a lower arm.

  In addition, the suspension drive control unit 450 is preliminarily provided with hydraulic characteristic information representing the relationship between the acceleration and acceleration signals in the X, Y, and Z axis directions obtained from the monitoring device 200, road surface information, and the hydraulic pressure in the damper 425. It is obtained and memorized by actual measurements such as experiments. Furthermore, the suspension drive control unit 450 estimates the vertical fluctuation amount of each tire 300 based on the acceleration and acceleration signal, the road surface state detection result, and the hydraulic characteristic information, and based on the estimated vertical fluctuation amount of the tire. The operation of the suspension drive source 410 is controlled, and the injection hydraulic pressure from the suspension drive source 410 to the damper 425 is controlled. As a result, the suspension drive control unit 450 performs active suspension control.

  According to the active suspension system having the above-described configuration, the above-described sensor unit 100 is provided, and traveling based on each acceleration signal in the X-axis direction (wheel rotation direction) for each rotation mechanism unit 500 output from the monitor device 200. Since the information on the road surface state is taken into the suspension drive control unit 450 and active suspension control is performed, it is possible to perform control with higher accuracy than before.

  For example, the type of tire mounted on the vehicle is different, and high-precision control is possible even if the frictional force between the tire and the road surface changes. Further, even a vehicle such as a 4WD vehicle that is individually driven and controlled for each tire can perform highly accurate control.

  The active suspension system may be applied to a seat seat suspension as in the conventional example described above.

  Next, a third embodiment of the present invention will be described.

  FIG. 32 is a schematic configuration diagram showing an active suspension system according to the third embodiment of the present invention. In the figure, the same components as those of the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted. Further, the difference between the third embodiment and the second embodiment is that in the third embodiment, one monitor device 200A and a sensor unit 100A provided in each rotation mechanism unit 500 are used.

  The sensor unit 100A has the same configuration as that of the sensor unit 100 of the above embodiment, and differs from the sensor unit 100 of the above embodiment in that an information request instruction including its own identification information is received from the monitor device 200A. The program of the CPU 141 is set so that each acceleration is detected and the detection result is transmitted as digital information together with its own identification information.

  The monitor device 200A has the same configuration as the monitor device 200 of the above-described embodiment, and differs from the monitor device 200 of the above-described embodiment in that the control unit 230 uses the identification information of the sensor unit 100A provided in each tire 300. An operation unit (not shown) for storing in advance is provided, and during driving, the sensor units 100A of all tires 300 provided in the vehicle in a predetermined order or at random, When the program of the control unit 230 is set to transmit the information request instruction including the identification information of the sensor unit 100A, and when the detection result is output to the suspension drive control unit 450, the vehicle together with the detection result This is to output detection position information indicating the detection result corresponding to the rotation mechanism unit 500 at which position of the head.

  According to the above configuration, detection results can be acquired from all the sensor units 100A by one monitor device 200A.

  Next, a fourth embodiment of the present invention will be described. In the fourth embodiment, an antilock brake system to which the road surface information detection system described above is applied will be described.

  FIG. 33 is a schematic configuration diagram showing an antilock brake system according to a fourth embodiment of the present invention, and FIG. 34 is a configuration diagram showing an electric circuit of a monitor device according to the fourth embodiment. In the figure, the same components as those of the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted.

  In the figure, 100 is a sensor unit, 200 is a monitoring device, 300 is a tire, 500 is a rotation mechanism, 600 is a braking control unit, 610 is a brake pedal, 620 is a master cylinder for braking, and 630 is a hydraulic pressure for braking. The pressure control valve 640 is an actuator for driving the brake.

  As described above, the monitor device 200 is fixed to each tire house 3, and each monitor device 200 is connected to the brake control unit 600 by a cable as shown in FIG. Operates and sends the detected road surface condition information to the braking control unit 600.

  The braking control unit 600 is mainly composed of a well-known CPU, captures detection results output from the sensors 510 and 520 that detect the rotation speed of each tire 300, and captures road surface state information output from each monitor device 200. Based on these, the pressure control valve 630 is controlled.

  That is, in the braking control unit 600, the X-, Y-, and Z-axis direction acceleration and acceleration signals obtained from the monitor device 200, and strain characteristic information representing the relationship between the road surface state information and the strain amount of the tire 300 are previously tested. It is calculated | required and memorize | stored by actual measurement. Further, the braking control unit 600 estimates the distortion amount of each tire 300 based on the acceleration, the acceleration signal, the road surface state detection result, and the distortion characteristic information, and the estimated tire distortion amount and the rotation of each tire 300. The pressure control valve 630 is controlled based on the number of detection results, and the brake driving actuator 640 is driven. As a result, the braking control unit 600 performs braking control.

  That is, when the brake pedal 610 is depressed, the hydraulic pressure in the master cylinder 620 increases, and this hydraulic pressure is transmitted to the brake drive actuator 640 of each tire 300 via the pressure control valve, thereby controlling the rotation of each tire 300. Power is applied.

  The braking control unit 600 automatically controls the operation state of each pressure control valve 630 to prevent the tire 300 from locking and slipping. The braking control unit 600 electrically controls the operating state of each pressure control valve 630 based on the road surface information output from the monitor device 200.

  According to the antilock brake system configured as described above, for example, a conventional general antilock brake system uses a detection result output from a sensor that detects the number of rotations of the tire 300 mounted on the vehicle. The pressure control valve 630 is taken in and controlled, but the sensor unit 100 is provided, and based on the acceleration signals in the X-axis direction (wheel rotation direction) for each rotation mechanism unit 500 output from the monitor device 200. Since the information on the traveling road surface state is taken into the braking control unit 600 and the braking control is performed, it is possible to perform the control with higher accuracy than before.

  For example, the type of tire mounted on the vehicle is different, and high-precision control is possible even if the frictional force between the tire and the road surface changes. Further, even a vehicle that individually controls driving for each tire such as a 4WD vehicle can perform highly accurate control.

  Further, as described above, in the present embodiment, the sensor unit 100 receives the electromagnetic wave radiated from the monitor device 200 and transmits the detection result when the electric energy is obtained. Even if it does not provide, the said effect can be acquired. In addition, in the configuration in which the sensor unit 100 includes the detection unit 150, by setting a program or the like so that the detection result is transmitted from the sensor unit 100 when receiving the identification information from the monitor device 200, an external input The detection result is not transmitted due to unnecessary noise, thereby preventing unnecessary electromagnetic radiation.

  In the above embodiment, the sensor unit 100 is fixed to the brake disk 520. However, the present invention is not limited to this, and any rotating body that rotates in the rotating mechanism unit 500 may be fixed to a rotating shaft (axle), a rotor, or the like. May be.

  In addition, transfer of digital information between the sensor unit 100 and the monitor device 200 may be performed by electromagnetic induction coupling using a coil, or by wire using a brush used for a motor or the like. Also good.

  Next, a fifth embodiment of the present invention will be described.

  FIG. 35 is a schematic configuration diagram showing an antilock brake system according to a fifth embodiment of the present invention, and FIG. 36 is a configuration diagram showing an electric circuit of a monitor device according to the fifth embodiment. In the figure, the same components as those of the above-described embodiment are denoted by the same reference numerals and the description thereof is omitted. Further, the difference between the fifth embodiment and the fourth embodiment is that in the fifth embodiment, one monitor device 200A and the sensor unit 100A provided in each rotation mechanism unit 500 are used.

  The sensor unit 100A has the same configuration as that of the sensor unit 100 of the above embodiment, and differs from the sensor unit 100 of the above embodiment in that an information request instruction including its own identification information is received from the monitor device 200A. The program of the CPU 141 is set so that each acceleration is detected and the detection result is transmitted as digital information together with its own identification information.

  The monitor device 200A has the same configuration as the monitor device 200 of the above-described embodiment, and differs from the monitor device 200 of the above-described embodiment in that the control unit 230 uses the identification information of the sensor unit 100A provided in each tire 300. The operation unit 260 is stored in advance, and during driving, the sensor units 100A of all the tires 300 provided in the vehicle are arranged in a predetermined order or randomly. The program of the control unit 230 is set to transmit the information request instruction including the identification information, and when the detection result is output to the braking control unit 600A, the rotation position of the vehicle along with the detection result The detection position information indicating whether the detection result corresponds to the mechanism unit 500 is output.

  According to the above configuration, detection results can be acquired from all the sensor units 100A by one monitor device 200A.

  In addition, you may comprise the system which combined the structure of said each embodiment, or replaced some structural parts.

  Moreover, in the said embodiment, although both said 1st and 2nd frequency was 2.45 GHz, it is not limited to this, If it is a frequency of 1 GHz or more as mentioned above, it will be electromagnetic waves by the metal in a tire The detection data by the sensor unit 100 can be obtained with high accuracy by greatly reducing the influence of reflection and blocking of the light, and the first and second frequencies may be different frequencies. These first and second frequencies are preferably set as appropriate during design.

  In this embodiment, the anti-lock brake system for a four-wheel vehicle has been described as an example. However, the same effect can be obtained even in a vehicle other than four wheels, for example, a two-wheel vehicle or a vehicle having six or more wheels. It goes without saying that we can do it.

The block diagram which shows the electric system circuit of the road surface state detection system in 1st Embodiment of this invention. The figure explaining the mounting state of the sensor unit and monitor apparatus in 1st Embodiment of this invention. The figure explaining the mounting state of the sensor unit in 1st Embodiment of this invention. The figure explaining the other mounting state of the sensor unit in 1st Embodiment of this invention. The block diagram which shows the electric system circuit of the sensor unit in 1st Embodiment of this invention. 1 is an external perspective view showing a semiconductor acceleration sensor according to a first embodiment of the present invention. BB direction arrow sectional view in FIG. CC sectional view taken along the line CC in FIG. The disassembled perspective view which shows the semiconductor acceleration sensor in 1st Embodiment of this invention. The block diagram which shows the electric system circuit of the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure which shows the bridge circuit which detects the acceleration of a X-axis direction using the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure which shows the bridge circuit which detects the acceleration of the Y-axis direction using the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure which shows the bridge circuit which detects the acceleration of a Z-axis direction using the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure explaining operation | movement of the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure explaining operation | movement of the semiconductor acceleration sensor in 1st Embodiment of this invention. The figure explaining the acceleration of the X, Y, Z-axis direction which the acceleration sensor of the sensor unit in 1st Embodiment of this invention detects. The figure which shows the actual measurement result of the acceleration of a Z-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a Z-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a Z-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a X-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a X-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a X-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of the Y-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of the Y-axis direction in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a X-axis direction when a brake is applied in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a Z-axis direction when a brake is applied in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of the wheel rotation direction in the dry paved road at the time of fine weather in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a wheel rotation direction in the paved road where the road surface was covered with the water film of the depth of 2-3 mm at the time of rain in 1st Embodiment of this invention. The figure which shows the actual measurement result of the acceleration of a wheel rotation direction in the paved road where the whole surface is frozen in 1st Embodiment of this invention. The schematic block diagram which shows the active suspension system of 2nd Embodiment of this invention The block diagram which shows the suspension main body in 2nd Embodiment of this invention. The schematic block diagram which shows the active suspension system of 3rd Embodiment of this invention The schematic block diagram which shows the braking control apparatus of the vehicle in the anti-lock brake system of 4th Embodiment of this invention. The block diagram which shows the electric system circuit of the monitor apparatus in 4th Embodiment of this invention The schematic block diagram which shows the braking control apparatus of the vehicle in 5th Embodiment of this invention. The block diagram which shows the electric system circuit of the monitor apparatus in 5th Embodiment of this invention The figure explaining the rotation speed detection mechanism of the wheel in a prior art example The figure explaining the rotation speed detection mechanism of the wheel in a prior art example

Explanation of symbols

  100,100A ... sensor unit, 110 ... antenna, 120 ... antenna switcher, 130 ... rectifier circuit, 131,132 ... diode, 133 ... capacitor, 134 ... resistor, 140 ... central processing unit, 141 ... CPU, 142 ... D / A conversion Circuit: 143: Storage unit, 150: Detection unit, 151: Diode, 152: A / D conversion circuit, 160: Transmission unit, 161: Oscillation circuit, 162: Modulation circuit, 163: High frequency amplification circuit, 170, 170B: Sensor unit , 171 ... Acceleration sensor, 172 ... A / D conversion circuit, 173 ... Pressure sensor, 174 ... A / D conversion circuit, 200, 200A, 200B ... Monitor device, 210 ... Radiation unit, 211 ... Antenna, 212 ... Transmitter, 220 ... receiving unit, 221 ... antenna, 222 ... detection unit, 230 ... control unit, 240 ... calculation unit, 250 ... storage unit, 260 ... operation unit, 300 ... tyre, 301 ... cap tread, 302 ... under tread, 303A, 303B ... Belt, 304 ... Carcass, 305 ... Tire body, 306 ... Rim, 410 ... Suspension Power source, 420 ... Suspension body, 421 ... Upper mount, 422 ... Spring upper seat, 423 ... Coil spring, 424 ... Rubber member, 425 ... Damper, 426 ... Damper connecting member, 431 ... Outer cylinder, 432 ... Piston rod, 433 ... Guide, 434 ... Bracket, 440 ... Hub carrier, 510,520 ... Rotation speed sensor, 600,600A ... Brake control unit, 610 ... Brake pedal, 620 ... Master cylinder, 630 ... Pressure control valve, 640 ... Brake drive actuator, 3 ... Tire house, 10 ... Semiconductor acceleration sensor, 11 ... Pedestal, 12 ... Silicon substrate, 13 ... Diaphragm, 13a-13d ... Diaphragm piece, 14 ... Thick film part, 15 ... Weight, 19A, 19B ... Support, 191 ... Outer frame portion, 192 ... post, 193 ... beam portion, 194 ... projection portion, 194a ... projection tip, 31A to 31C ... voltage detector, 32A to 32C ... DC power supply, Rx1 to Rx4, Ry1 to Ry4, Rz1 to Rz4 ... Piezoresistors (diffusion resistors).

Claims (29)

A rotation mechanism provided on a vehicle body and including a rotating body that fixes the wheel and rotates the wheel and the wheel, detects acceleration generated in the rotation direction along with the rotation and converts it into an electrical signal. And a sensor unit for converting the detected acceleration signal into digital data and transmitting digital information including the digital data;
A monitor device that is provided on a vehicle body, receives digital information transmitted from the sensor unit, and acquires the acceleration signal;
The monitor device is
Road surface state storage means for storing a plurality of types of information relating to fluctuation characteristics of the acceleration signal detected for each state of the road surface on which the vehicle travels in association with information on the road surface state;
Road surface state specifying means for specifying a road surface state corresponding to the received acceleration signal based on the acceleration signal received from the sensor unit and information on the fluctuation characteristics of the acceleration signal stored in the road surface state storage means;
A road surface state detection system comprising: road surface state information output means for extracting and outputting information relating to the road surface state specified by the road surface state specifying means from the road surface state storage means. The road surface state detection system according to claim 1, wherein the road surface state storage unit stores a variation characteristic pattern of the acceleration signal as information regarding the variation characteristic of the acceleration signal. The road surface state storage unit stores information obtained by performing a predetermined processing on the variation characteristic of the acceleration signal as information regarding the variation characteristic of the acceleration signal. The road surface condition detection system described. The road surface condition detection system according to claim 1, wherein the sensor unit is provided on the rotating body. The sensor unit is
Means for receiving electromagnetic waves of a first frequency;
Means for converting the energy of the received electromagnetic wave of the first frequency into electric energy for driving;
Means for operating with the electrical energy and transmitting the digital information using electromagnetic waves of a second frequency,
The monitor device is
Means for radiating electromagnetic waves of the first frequency;
Means for receiving electromagnetic waves of the second frequency;
The road surface condition detection system according to claim 1, further comprising means for extracting the digital information from the received electromagnetic wave of the second frequency.   The road surface condition detection system according to claim 5, wherein the first frequency and the second frequency are the same frequency. The sensor unit has storage means for storing identification information unique to itself, and means for transmitting the identification information included in the digital information,
The road surface state detection system according to claim 1, wherein the monitor device includes means for identifying the rotation mechanism unit based on the identification information. The road surface state detection system according to claim 1, wherein the sensor unit includes a semiconductor acceleration sensor having a silicon piezo-type diaphragm that detects acceleration in the rotation direction. In the vehicle active suspension system configured to drive the suspension actuator according to the detection result of the vertical movement of the wheel and generate the braking force so as to reduce the vertical movement of the vehicle body,
Provided in a rotating mechanism unit including a rotating body that is provided on the vehicle body and rotates the wheel while fixing the wheel, and detects acceleration generated in the rotating direction along with the rotation and converts it into an electrical signal and the detection. A sensor unit for converting the acceleration signal into digital data and transmitting digital information including the digital data;
A monitor device that receives the digital information transmitted from the sensor unit, acquires the acceleration signal, and outputs road surface state information representing a state of a traveling road surface based on the acceleration signal;
Drive means for driving the suspension actuator based on road surface condition information output from the monitor device;
The monitor device is
Road surface state storage means for storing a plurality of types of information relating to fluctuation characteristics of the acceleration signal detected for each state of the road surface on which the vehicle travels in association with information on the road surface state;
Road surface state specifying means for specifying a road surface state corresponding to the received acceleration signal based on the acceleration signal received from the sensor unit and information on the fluctuation characteristics of the acceleration signal stored in the road surface state storage unit;
An active suspension system, comprising: road surface state information output means for extracting and outputting information relating to the road surface state specified by the road surface state specifying means from the road surface state storage means. The active suspension system according to claim 9, wherein the road surface state storage unit stores a variation characteristic pattern of the acceleration signal as information on the variation characteristic of the acceleration signal. The road surface state storage means stores information obtained by performing a predetermined processing on the fluctuation characteristics of the acceleration signal as information on the fluctuation characteristics of the acceleration signal. Active suspension system as described. The active suspension system according to claim 9, wherein the sensor unit is provided on the rotating body. The sensor unit is
Means for receiving electromagnetic waves of a first frequency;
Means for converting the energy of the received electromagnetic wave of the first frequency into electric energy for driving;
Means for operating with the electrical energy and transmitting the digital information using electromagnetic waves of a second frequency,
The monitor device is
Means for radiating electromagnetic waves of the first frequency;
Means for receiving electromagnetic waves of the second frequency;
The active suspension system according to claim 9, further comprising means for extracting the digital information from the received electromagnetic wave of the second frequency.   The active suspension system according to claim 13, wherein the first frequency and the second frequency are the same frequency. The sensor unit has storage means for storing identification information unique to itself, and means for transmitting the identification information included in the digital information,
The active suspension system according to claim 9, wherein the monitor device includes means for identifying the rotation mechanism unit based on the identification information. The active suspension system according to claim 9, wherein the sensor unit includes a semiconductor acceleration sensor having a silicon piezo diaphragm that detects acceleration in the rotation direction. In the vehicle anti-lock brake system configured to drive the actuator for driving the brake according to the detection result of the brake operation state of the vehicle and generate the target braking force,
Provided in a rotating mechanism unit including a rotating body that is provided on the vehicle body and rotates the wheel while fixing the wheel, and detects acceleration generated in the rotating direction along with the rotation and converts it into an electrical signal and the detection. A sensor unit for converting the acceleration signal into digital data and transmitting digital information including the digital data;
A monitor device that receives the digital information transmitted from the sensor unit, acquires the acceleration signal, and outputs road surface state information representing a state of a traveling road surface based on the acceleration signal;
Driving means for driving the brake driving actuator based on road surface state information output from the monitor device;
The monitor device is
Road surface state storage means for storing a plurality of types of information relating to fluctuation characteristics of the acceleration signal detected for each state of the road surface on which the vehicle travels in association with information on the road surface state;
Road surface state specifying means for specifying a road surface state corresponding to the received acceleration signal based on the acceleration signal received from the sensor unit and information on the fluctuation characteristics of the acceleration signal stored in the road surface state storage unit;
An anti-lock brake system, comprising: road surface state information output means for extracting and outputting information relating to the road surface state specified by the road surface state specifying means from the road surface state storage means. The anti-lock brake system according to claim 17, wherein the road surface state storage unit stores a variation characteristic pattern of the acceleration signal as information regarding a variation characteristic of the acceleration signal. The road surface state storage means stores information obtained by performing a predetermined processing on the fluctuation characteristics of the acceleration signal as information on the fluctuation characteristics of the acceleration signal. Anti-lock brake system as described. The anti-lock brake system according to claim 17, wherein the sensor unit is provided on the rotating body. The sensor unit is
Means for receiving electromagnetic waves of a first frequency;
Means for converting the energy of the received electromagnetic wave of the first frequency into electric energy for driving;
Means for operating with the electrical energy and transmitting the digital information using electromagnetic waves of a second frequency,
The monitor device is
Means for radiating electromagnetic waves of the first frequency;
Means for receiving electromagnetic waves of the second frequency;
The anti-lock brake system according to claim 17, further comprising means for extracting the digital information from the received electromagnetic wave of the second frequency.   The anti-lock brake system according to claim 21, wherein the first frequency and the second frequency are the same frequency. The sensor unit has storage means for storing identification information unique to itself, and means for transmitting the identification information included in the digital information,
The anti-lock brake system according to claim 17, wherein the monitor device includes means for identifying the rotation mechanism unit based on the identification information. The anti-lock brake system according to claim 17, wherein the sensor unit includes a semiconductor acceleration sensor having a silicon piezo-type diaphragm that detects acceleration in the rotation direction. A sensor unit that is provided on a vehicle body side and is provided in a rotating mechanism that includes a rotating body that fixes and rotates the wheel and the wheel, and that detects acceleration generated with rotation,
Means for detecting acceleration generated in the rotation direction with rotation and converting it into an electrical signal;
Means for converting the acceleration signal into digital data;
And a means for transmitting digital information including the digital data. Means for receiving electromagnetic waves of a first frequency;
Means for converting the energy of the received electromagnetic wave of the first frequency into electric energy for driving;
26. The sensor unit according to claim 25, further comprising: a unit that operates by the electric energy and transmits the digital information using an electromagnetic wave having a second frequency.   27. The sensor unit according to claim 26, wherein the first frequency and the second frequency are the same frequency. A storage means storing identification information unique to itself;
26. The sensor unit according to claim 25, further comprising means for transmitting the identification information included in the digital information. The sensor unit according to claim 25, further comprising a semiconductor acceleration sensor having a silicon piezo-type diaphragm that detects acceleration in the rotation direction.

Images