JP2009261155A - Controller for electric vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a controller for an electric vehicle which can sufficiently exhibit advantages of the electric vehicle equipped with a wheel-rotating motor for every wheel. <P>SOLUTION: A drive control unit 700 performs the drive control of the wheel-rotating motors 3a to 3d for rotating each tire 2a to 2d based on the acceleration information of the tires (wheels) 2a to 2d in X, Y, Z axis directions detected with the triaxial acceleration sensor of a sensor unit 100, the rotation angle of a steering wheel 8 detected with a rotation angle sensor 530, the yaw rate information detected with a yaw rate sensor 540, the stepping angle of an acceleration pedal 6 detected with a sensor 510, and the stepping angle of a brake pedal 7 detected with a sensor 520. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a control device for an electric vehicle provided with a wheel rotation motor for each wheel.

  2. Description of the Related Art Conventionally, development for shifting from an automobile using an engine as a power source to an electric car using a motor as a power source has been made. Unlike gasoline engines, electric vehicles are attracting attention because they do not release exhaust gas that causes air pollution.

  This type of electric vehicle was originally devised by replacing the conventional engine with a motor. However, the in-wheel motor has a built-in motor in each wheel because of the high space efficiency of the vehicle and the high transmission efficiency of the driving force. The system is being adopted.

  As such an in-wheel motor system, for example, JP-A-2004-1115014 (Patent Document 1), JP-A-2005-47481 (Patent Document 2), JP-A-2005-289322 (Patent Document 3). JP-A-2006-1313 (Patent Document 4), JP-A-2006-1314 (Patent Document 5) and the like are known.

  The in-wheel motor system disclosed in Patent Document 1 described above improves the load holding performance of a vehicle by reducing fluctuations in the tire ground contact force of the vehicle.

  In the in-wheel motor system disclosed in Patent Document 2, in the configuration in which the in-wheel motor is supported in the vertical direction by the damper and the spring member arranged in parallel, the motor mass is reduced in order to reduce the ground load fluctuation near the unsprung resonance. This is an improvement of the structure that acts as the weight of the dynamic damper.

  An in-wheel motor system disclosed in Patent Document 3 is an in-wheel in an all-wheel drive vehicle in which either a front wheel or a rear wheel is driven by an internal combustion engine and the other is driven by an electric motor mounted on a wheel portion. When the motor system is not used in the entire drive area and the in-wheel motor is mounted only on the driven wheel and used only as an assist, the power transmission path between the wheel and the motor is smoothly interrupted when not in use. It is equipped with a power interrupting means.

The in-wheel motor systems disclosed in Patent Documents 4 and 5 are improved in the sealing performance of the linear motion guide used in the in-wheel motor system. This prevents dust and foreign matter from entering the linear motion guide that elastically supports the wheel motor, and reduces the increase in sliding resistance and the increase in frictional resistance in the vertical movement of the in-wheel motor.
JP 2004-1115014 A JP-A-2005-47481 JP 2005-289322 A JP 2006-1313 A JP 2006-1314 A

  However, not only the in-wheel motor system but also the drive control of an electric vehicle equipped with a wheel rotation motor for each wheel can be operated in the same way as a vehicle using a conventional engine by simply changing the power supply amount to the motor. Therefore, the control that takes advantage of the electric vehicle provided with the wheel rotation motor for each wheel is not performed.

  The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide an electric vehicle control device that can sufficiently exhibit the advantages of an electric vehicle including a wheel rotation motor for each wheel. It is in.

  In order to achieve the above object, the present invention provides a control device for an electric vehicle provided with a separate wheel rotation motor for each wheel, and is attached to each wheel, and the acceleration in the rotation direction of the wheel and the rotation axis direction A plurality of sensor units having a triaxial acceleration sensor that detects acceleration and acceleration in a direction orthogonal to the rotation axis and outputs information of each acceleration; and a turning angle setting means for setting a traveling direction angle of the vehicle; A yaw rate sensor that detects either the rotation speed or angular velocity of the vehicle body with respect to a predetermined vertical axis, outputs the detected yaw rate information, and detects the depression angle of the accelerator pedal. A first depression angle detection sensor for outputting; a second depression angle detection sensor for detecting depression angle of the brake pedal and outputting information on the depression angle; Acceleration information output from the acceleration sensor, turning angle information set by the turning angle setting means, yaw rate information output from the yaw rate sensor, and depression of the accelerator pedal output from the first depression angle detection sensor Drive control means for inputting angle information and brake pedal depression angle information output from the second depression angle detection sensor, and performing drive control of a wheel rotation motor that rotates each wheel based on the information. A control device for an electric vehicle equipped with

  In the control apparatus for an electric vehicle according to the present invention, the drive control unit performs drive control by setting the rotation direction and power supply amount of the wheel rotation motor that rotates each wheel based on the information acquired from each sensor. .

  According to the control device for an electric vehicle of the present invention, the driving direction is controlled by setting the rotation direction and the power supply amount of the wheel rotation motor that rotates each wheel based on the information acquired from each sensor. It is possible to perform precise drive control that can fully exhibit the advantages of the above.

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

  1 is a schematic configuration diagram showing a control device for an electric vehicle according to an embodiment of the present invention, FIG. 2 is a schematic configuration diagram showing a hydraulic brake control system of the electric vehicle according to an embodiment of the present invention, and FIG. FIG. 4 is a block diagram showing an electric system circuit of an acceleration sensor unit in one embodiment of the present invention, and FIG. 5 is a block diagram of a receiving unit in one embodiment of the present invention. It is a block diagram which shows an electric system circuit. In the present embodiment, a control device for a four-wheel electric vehicle will be described as an example.

  In the figure, 1 is a vehicle, 2a to 2d are tires (wheels), 3a to 3d are wheel rotation motors, 4a to 4d are axles, 5a to 5d are sensor mounting plates, 6 is an accelerator pedal, 7 is a brake pedal, 8 is a handle, 100 is a sensor unit, 200 is a receiving unit, 510 is an accelerator pedal depression angle detection sensor, 520 is a brake pedal depression angle detection sensor, 530 is a handle rotation angle detection sensor, 540 is a yaw rate sensor, and 700 is a drive control unit It is. The drive control unit 700 includes a control unit 710, a motor drive unit 720, and an operation unit 730. In the present embodiment, the handle 8 and the handle rotation angle detection sensor 530 constitute turning angle setting means. Further, two left and right push button switches may be provided as the turning angle setting means, and the turning angle may be set electrically using these switches.

  In the present embodiment, in each of the sensor unit 100 and the receiving unit 200, each electric system circuit is housed in a small casing having insulation and electromagnetic wave transmission, and each of the four sensor units 100 is connected to each sensor mounting plate. 5a to 5d are mounted, and each of the four receiving units 200 is arranged in each tire house (not shown) so that the sensor unit 100 and the receiving unit 200 have a one-to-one correspondence.

  The tires 2a to 2d are, for example, well-known tubeless radial tires. In the present embodiment, the tires 2a to 2d include a wheel and a rim, and are stored in a tire house (not shown). Furthermore, a receiving unit 200 is provided in each tire house. The sensor unit 100 is fixed to the sensor mounting plates 5a to 5d attached to the axles 4a to 4d of the tires 2a to 2d at the same radius from the center of the axles 4a to 4d. In the present embodiment, the rotation direction of the tires 2a to 2d is the X-axis direction, the axle direction of the tires 2a to 2d is the Y-axis direction, and the radial direction centered on the axles 4a to 4d of the tires 2a to 2d is the Z-axis direction. The following description will be given.

  620 is a hydraulic brake master cylinder connected to the brake pedal 7, 630 is a pressure control valve for controlling the brake hydraulic pressure, 640 is an actuator for driving the brake, and 700 is a drive control unit. The hydraulic pressure corresponding to the depression angle of the brake pedal 7 is transmitted through the pressure control valve 630 to change the braking force by each brake driving actuator 640, and the pressure is controlled by the control signal output from the control unit 710 of the drive control unit 700 The control force of each brake driving actuator 640 is changed by adjusting the control valve 630.

  The control unit 710 includes a control circuit including a well-known CPU and a memory storing a program, and includes four receiving units 200, an accelerator pedal depression angle detection sensor 510, a brake pedal depression angle detection sensor 520, a handle rotation Based on the information output from the angle detection sensor 530 and the yaw rate sensor 540, the pressure control valves 630a to 630d are controlled, and the power supplied to the motors 3a to 3d and the motors 3a via the motor driving unit 720 are controlled. The rotational direction of ˜3d is individually controlled for each of the motors 3a to 3d.

  That is, at the time of acceleration, by depressing the accelerator pedal 6, the driving power supplied from the motor driving unit 720 to each of the motors 3a to 3d is increased, and the rotation speed of the motors 3a to 3d is increased.

  Further, at the time of braking, the hydraulic pressure in the master cylinder 620 is increased by depressing the brake pedal 7, etc., and this hydraulic pressure is transmitted to the brake driving actuators 640 of the tires 2a to 2d via the pressure control valve 630. A braking force is applied to the rotation of the tires 2a to 2d.

  Further, the control unit 710 stores information on the mounted tire input from the operation unit 730 in the memory and switches forward and backward based on the switch setting of the operation unit 730. Examples of the information on the mounted tire include a tire model number, a tire radius, and a diameter. Further, a table in which tire model numbers and tire radius and diameter information are associated with each other may be stored in the memory of the control unit 710 in advance.

  Further, the control unit 710 obtains the mounted tire information stored in the memory, the acceleration information input from the receiving unit 200, the rotation angle information of the handle 8 obtained from the rotation angle detection sensor 530, and the yaw rate sensor 540. Based on the yaw rate information, the rotation speed and rotation direction of each of the motors 3a to 3d are individually controlled. This control will be described later.

  As described above, the sensor unit 100 is fixed at a predetermined position on the sensor mounting plates 5a to 5d, and the X, Y, and Y in the tires 2a to 2d by the acceleration sensor 10 described later provided in the sensor unit 100. The acceleration in the Z-axis direction is detected, and the values of acceleration signals in the X, Y, and Z-axis directions are converted into digital values. Further, the sensor unit 100 generates digital information including digital values of acceleration in the X, Y, and Z axis directions and transmits the digital information at predetermined intervals. The digital information includes identification information unique to each sensor unit 100 in addition to the digital value of the acceleration.

  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. 4, the sensor unit 100 includes an antenna 110, an antenna switch 120, a rectifier circuit 130, a central processing unit 140, a transmission unit 150, and a sensor unit 160.

  The antenna 110 is for communicating with the receiving unit 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 the connection between the antenna 110 and the rectifier circuit 130 and the connection between the antenna 110 and the transmitter 150 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 transmission unit 150, and the sensor unit 160. As the capacitor 133, a known super capacitor known as a large-capacitance capacitor is used.

  The central processing unit 140 includes a known CPU 141 and a storage unit 142. The CPU 141 operates based on a program stored in the semiconductor memory of the storage unit 142. When the CPU 141 is driven by being supplied with electric energy, the CPU 141 includes a digital value of the acceleration detection result acquired from the sensor unit 160 and identification information described later. A process for generating digital information and transmitting the digital information to the receiving unit 200 is performed. Further, the identification information unique to the sensor unit 100 is stored in the storage unit 142 in advance.

  In the present embodiment, the central processing unit 140 is programmed to transmit the digital information to the receiving unit 200 when receiving the radio wave of the first frequency from the receiving unit 200. It is preferable to set appropriately considering the traveling speed of the vehicle.

  The storage unit 142 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 142 at the time of manufacture.

  The transmission unit 150 includes an oscillation circuit 151, a modulation circuit 152, and a high-frequency amplification circuit 153. The transmission unit 150 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 oscillated by the oscillation circuit 151. Based on the information signal input from the unit 140, the signal is modulated by the modulation circuit 152, and the frequency of the 2.45 GHz band (second frequency) different from the first frequency is passed through the high frequency amplifier circuit 153 and the antenna switch 120. A high frequency current is supplied to the antenna 110. In the present embodiment, the first frequency and the second frequency are set to different frequencies. However, the first frequency and the second frequency are set to the same frequency, and the sensor unit 100 and the receiving unit 200 are set to the same frequency. You may make it synchronize the timing of transmission / reception.

  The frequency of the carrier wave is not limited to the 2.45 GHz band, and any frequency band that is permitted to be used with low power can be used. For example, a frequency such as a 13 MHz band, a 315 MHz band, a 400 MHz band, a 900 MHz band, or a 1200 MHz band may be used. Further, signals and energy may be transmitted between the sensor unit 100 and the receiving unit 200 by electromagnetic induction.

  The sensor unit 160 includes the acceleration sensor 10 and an A / D conversion circuit 161.

  The acceleration sensor 10 is constituted by a semiconductor acceleration sensor as shown in FIGS.

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

  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 has a piezoresistor Rx1, Rx2, Rz1, and Rz2 formed on one diaphragm piece 13a, and a piezoresistor Rx3 on the other diaphragm piece 13b. , Rx4, Rz3, and Rz4 are formed. Piezoresistors Ry1 and Ry2 are formed on one diaphragm piece 13c 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 supports 18A and 18B are provided so as to connect the outer frame portion 181 having a rectangular frame shape, the four support columns 182 standing at the four corners of the fixed portion, and the tip portions of the support columns. A cross-shaped beam portion 183, and a conical projection portion 184 provided at a central intersection of the beam portion 183.

  The outer frame portion 181 is fitted and fixed to the outer peripheral portion of the pedestal 11 so that the protruding portion 184 is located on the other surface side of the diaphragm 13, that is, on the side where the weight 15 does not exist. Here, the tip 184a of the protrusion 184 is set 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 protrusion 184 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 extended in the direction in which the forces 41 and 42 are applied, but the displacement is supported and limited by the apex 184a of the protrusion 184, so that each diaphragm piece 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 184 a of the projection 184 serving as a fulcrum, so that it is parallel to the surface of the diaphragm 13. Acceleration in any direction can be detected.

  The semiconductor acceleration sensor 10 can detect accelerations in the X, Y, and Z axis directions orthogonal to each other generated in each of the four tires 2a to 2d of the vehicle 1 when the vehicle 1 is traveling. .

  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.

  In this embodiment, as described above, the frequency of the 2.45 GHz band is used as the first and second frequencies so that the metal is hardly affected. Thus, in order to make it less susceptible to the influence of metal, it is preferable to use a frequency of 1 GHz or more as the first and second frequencies.

  The receiving unit 200 is connected to the drive control unit 700 and the control unit 710 by a cable, and operates by electric energy sent from the drive control unit 700.

  As shown in FIG. 5, the electric circuit of the receiving unit 200 includes a radiation unit 210, a wave receiving unit 220, a control unit 230, and a calculation unit 240. 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 for radiating an electromagnetic wave signal having a predetermined frequency in the 2.45 GHz band (the above first frequency) and a transmission unit 212. Based on an instruction from the control unit 230, the antenna unit 211 The electromagnetic wave having the first frequency is radiated.

  In the present embodiment, by radiating electromagnetic waves from the radiation unit 210, a voltage of 3 V or more can be stored in the capacitor 133 as electrical energy sufficient to drive the sensor unit 100 at all times.

  As an example of the transmission unit 212, similarly to the transmission unit 150 of the sensor unit 100, a configuration including an oscillation circuit 151, a modulation circuit 152, and a high frequency amplification circuit 153 can be given. 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 receiving unit 200.

  The wave receiving unit 220 includes an antenna 221 for receiving an electromagnetic wave having a predetermined frequency (the 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 electromagnetic wave having the second frequency received by is detected, and a digital signal obtained by the detection is output to the arithmetic unit 250. An example of the detection unit 222 includes a circuit including a diode and an analog / digital converter that converts a signal detected by the diode into digital data.

  When electric energy is supplied from the drive control unit 700 and the operation is started, the control unit 230 always drives the detection unit 222 and causes the detection unit 222 to output a digital signal to the calculation unit 240. Further, the control unit 230 transmits radio waves to the sensor unit 100 via the transmission unit 212 when receiving an instruction from the calculation unit 240.

  The calculation unit 240 calculates the acceleration in the X, Y, and Z axis directions based on the digital signal output from the detection unit 222 and outputs the acceleration to the control unit 710 of the drive control unit 700.

  Further, when the calculation unit 240 detects a change in driving operation based on information received from the control unit 710, for example, driving such as loosening the driver's stepping on the accelerator pedal, stepping on the brake pedal, turning the handle, etc. When a change in operation is detected, a transmission command is output to the control unit 230 to instruct the sensor unit 100 to transmit radio waves via the oscillation unit 212. Thereby, the change of the detected acceleration of each sensor unit 100 caused by the change of the driving operation can be quickly acquired.

  Further, as the accelerator pedal depression angle detection sensor 510, the brake pedal depression angle detection sensor 520, and the handle rotation angle detection sensor 530 in the present embodiment, for example, a non-contact type using a magnet, a hall element, and an IC (integrated circuit). For example, as shown in FIGS. 16 and 17, the rotation angle sensor RS changes the output voltage ratio (%) of the output voltage Vout to the input voltage Vin in accordance with the rotation angle. Is.

  Also, as is well known, the yaw rate sensor 540 detects the speed or angular velocity at which the turning angle of the vehicle turns when the cornering vehicle is viewed from above, and the detection result is electrically detected. It is output as a signal.

  Next, electric vehicle control processing in the present embodiment will be described with reference to the processing flowcharts shown in FIGS. 18 is a flowchart showing the entire control process, FIG. 19 is a flowchart showing the running speed control process, FIG. 20 is a flowchart showing the running speed deceleration process, and FIG. 21 is a flowchart showing the running direction control process.

  When the operation starts, the control unit 710 of the drive control unit 700 acquires information on the depression angle of the accelerator pedal 6 from the accelerator pedal depression angle detection sensor 510 (SA1), and based on the acquired depression angle information of the accelerator pedal 6. Then, a traveling speed control process described later is performed (SA2). Next, the control unit 710 acquires information on the depression angle of the brake pedal 7 from the brake pedal depression angle detection sensor 520 (SA3), and performs a traveling speed deceleration process, which will be described later, based on the acquired depression angle information of the brake pedal 7. (SA4), and further, information on the rotation angle of the handle 8 is acquired from the handle rotation angle detection sensor 530 (SA5), and a travel direction control process described later is performed based on the acquired rotation angle information of the handle 8 (SA6). .

  In the travel speed control process, the control unit 710 determines whether or not the depression angle of the accelerator pedal 6 is 0 degrees (SB1). When the depression angle of the accelerator pedal 6 is other than 0 degrees, four receptions are performed. Based on the acceleration in the X-axis direction (acceleration in the rotational direction of the wheel) among the acceleration values in the X-, Y-, and Z-axis directions detected by the four sensor units 100 obtained through the units 200, respectively. The number of rotations of the wheels (tires 2a to 2d) is obtained (SB2).

  The acceleration in the X-axis direction changes with a sine wave having a rotation cycle of the tires 2a to 2d, as shown in FIGS. 22 to 24, FIG. 22 is a diagram showing a change in acceleration in the X-axis direction during traveling at a speed of 2.5 km / h, and FIG. 23 is a diagram showing a change in acceleration in the X-axis direction during traveling at a speed of 20 km / h. 24 is a diagram showing a change in acceleration in the X-axis direction during traveling at a speed of 40 km / h. In addition, the minute vibration component which generate | occur | produces by the friction between a driving | running | working road surface and tire 2a-2d is superimposed on the signal waveform of each figure.

  Thus, since the rotation speed of the tires 2a to 2d increases as the traveling speed increases, the cycle in which the acceleration in the X-axis direction changes is shortened. Therefore, it is possible to obtain the rotation speed of the tires 2a to 2d from the acceleration in the X-axis direction. In the figure, the measured value has a sine wave shape because it is influenced by gravitational acceleration. That is, when the sensor unit 100 is positioned at the front part of the tires 2a to 2d (position at 90 degrees on the vehicle traveling direction side), the acceleration in the X-axis direction is obtained by subtracting the gravitational acceleration from the acceleration due to the rotation. When located at the rear of 2d (a position 90 degrees in the direction opposite to the vehicle traveling direction), the acceleration in the X-axis direction is obtained by adding the acceleration due to rotation to the acceleration due to rotation.

  Next, the control unit 710 calculates the traveling speed of the vehicle 1 using the rotation speed obtained in the processing of SB2 and the tire information stored in the memory (SB3), and further, the memory of the control unit 710. Each motor is connected via a motor drive unit 720 to a travel speed corresponding to the depression angle of the accelerator pedal 6 based on a correspondence table representing the relationship between the depression angle of the accelerator pedal 6 and the travel speed stored in advance. The power supplied to 3a to 3d is changed (SB4).

  As a result of the determination of SB1, when the depression angle of the accelerator pedal 6 is 0 degree, that is, when the accelerator pedal 6 is not depressed, the control unit 710 applies the motor drive unit 720 to each of the motors 3a to 3d. The power supply is stopped (SB5).

  In the travel speed control process, the travel speed of the vehicle 1 is obtained using the acceleration in the X-axis direction, but the travel speed of the vehicle 1 is obtained using the acceleration in the Z-axis direction (a direction orthogonal to the axle). Also good. That is, as shown in FIGS. 25 to 27, the acceleration in the Z-axis direction changes with a sine wave having a rotation cycle of the tires 2a to 2d, and the centrifugal force applied to the acceleration sensor 10 increases as the traveling speed increases. Therefore, the acceleration in the Z-axis direction also increases.

  25 to 27, FIG. 25 is a diagram showing a change in acceleration in the Z-axis direction when traveling at a speed of 2.5 km, and FIG. 26 is a diagram showing a change in acceleration in the Z-axis direction when traveling at a speed of 20 km / h. 27 is a diagram showing a change in acceleration in the Z-axis direction during traveling at a speed of 40 km / h. Thus, since the centrifugal force applied to the acceleration sensor 10 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 reason why the actually measured value has a sine wave shape is that it is affected by the gravitational acceleration as described above.

  In the travel speed deceleration process, the control unit 710 determines whether or not the depression angle of the brake pedal 7 is 0 degrees (SC1). If the depression angle of the brake pedal 7 is other than 0 degrees, the motor drive unit The power supply from 720 to each of the motors 3a to 3d is stopped (SC2). When the brake pedal 7 is depressed, the above-described hydraulic brake is in operation, so that the rotation of the tires 2a to 2d is braked by the operation of the brake driving actuator 640.

  Thereafter, control unit 710 determines whether or not the vehicle 1 is rocking based on the yaw rate information acquired from yaw rate sensor 540 (SC3). As a result of this determination, when the vehicle 1 is rocking, the control unit 710 causes each of the yaw rate acquired from the yaw rate sensor 540 to be 0 (zero) so that the rocking is decreased. The pressure control valves 630a to 630d are controlled to correct the braking force by each brake driving actuator 640 (SC4).

  It should be noted that when the brake pedal 7 is depressed and the hydraulic brake is operating, the X-axis direction (the wheel of the wheel) is used to perform comfortable braking except when sudden braking is applied according to the depression angle of the brake pedal 7. The pressure control valves 630a to 630d are controlled by the control unit 710 so that the traveling speed during deceleration changes smoothly based on the acceleration value in the rotation direction) or the acceleration value in the Z-axis direction (direction orthogonal to the axle). Then, the braking force by each brake driving actuator 640 may be corrected. As a result, it is possible to automatically control the vehicle body so that the stability of the vehicle body is maintained and appropriate braking is performed or the tires 2a to 2d are locked and no slip occurs.

  In the travel direction control process, the control unit 710 determines whether or not the value of the rotation angle of the handle 8 acquired from the rotation angle detection sensor 530 is 0 degrees (SD1), and the rotation angle of the handle 8 is 0 degrees. Otherwise, the power supply ratio to the wheel rotation motors 3a to 3d for rotating the left and right wheels according to the rotation angle is adjusted (SD2) to cause the vehicle 1 to make a turning motion. At this time, the control unit 710 controls the motor driving unit 720 so that the amount of power supplied to the wheel rotation motors 3 a to 3 d on the rotation direction side of the handle 8 is for wheel rotation on the side opposite to the rotation direction of the handle 8. It is set lower than the power supply amount to the motors 3a to 3d. In addition, when using the wheel rotation motors 3a to 3d that are unlikely to reduce the number of rotations only by reducing the power supply amount, the control unit 710 controls the pressure control valves 630a to 630d individually. Then, braking is performed by the brake driving actuators 640a to 640d corresponding to the wheel rotation motors 3a to 3d whose rotation speed is to be decreased, and the rotation speed is decreased.

  If the rotation angle of the handle 8 is 0 degree as a result of the determination of SD1, the power supply amount to the wheel rotation motors 3a to 3d for rotating the left and right wheels is set equal (SD3), and each sensor unit The power supply ratio to the wheel rotation motors 3a to 3d for rotating the left and right wheels is adjusted so that the acceleration value detected in 100 in the Y-axis direction (rotation axis direction) becomes 0 (zero) (SD4). In this way, by adjusting the power supply ratio so that the acceleration value in the Y-axis direction (rotation axis direction) becomes 0 (zero), the rotation speed generated by the difference in the characteristics of the wheel rotation motors 3a to 3d can be reduced. Stable running can be realized by suppressing the turning movement of the vehicle 1 caused by the difference or the difference in the radius of the tires 2a to 2d.

  In the process of SD4, the ratio of the power supplied to the wheel rotation motors 3a to 3d for rotating the left and right wheels is adjusted based on the yaw rate information acquired from the yaw rate sensor 540 so that the rotational swing of the vehicle body is reduced. It is also possible to use both of them.

  In the present embodiment, the driving power of the sensor unit 100 is covered by the electric energy of the radio wave received from the monitor device 200. However, a battery is provided in the sensor unit 100, and the sensor unit 100 is powered by the power supplied from the battery. May be driven.

  The present invention is not limited to the above-described embodiment, and can be applied to control various electric vehicles. For example, an electric vehicle using a motor other than an in-wheel motor, a vehicle that can be braked only by the motor or a vehicle that cannot be braked only by the motor, a wheel angle that changes following the rotation of the steering wheel, a wheel angle that changes The present invention can be applied to electric vehicles such as fixed ones.

The schematic block diagram which shows the control apparatus of the electric vehicle in one Embodiment of this invention. The schematic block diagram which shows the hydraulic brake control system of the electric vehicle in one Embodiment of this invention The block diagram which shows the electric system circuit of the electric vehicle in one Embodiment of this invention The block diagram which shows the electric system circuit of the acceleration sensor unit in one Embodiment of this invention The block diagram which shows the electric system circuit of the receiving unit in one Embodiment of this invention 1 is an external perspective view showing a semiconductor acceleration sensor according to an 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 one Embodiment of this invention. The block diagram which shows the electric system circuit of the semiconductor acceleration sensor in one Embodiment of this invention The figure which shows the bridge circuit which detects the acceleration of the X-axis direction using the semiconductor acceleration sensor in one 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 one 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 one Embodiment of this invention. The figure explaining operation | movement of the semiconductor acceleration sensor in one Embodiment of this invention. The figure explaining operation | movement of the semiconductor acceleration sensor in one Embodiment of this invention. The block diagram which shows an example of the rotation angle sensor in one Embodiment of this invention. The figure which shows the electrical property of the rotation angle sensor in one Embodiment of this invention. The flowchart which shows the whole control processing in one Embodiment of this invention. The flowchart which shows the traveling speed control process in one Embodiment of this invention. The flowchart which shows the traveling speed deceleration process in one Embodiment of this invention. The flowchart which shows the traveling direction control process in one Embodiment of this invention. The figure which shows the acceleration change of the X-axis direction at the time of driving | running | working at 2.5 km / h in one Embodiment of this invention. The figure which shows the acceleration change of the X-axis direction at the time of the driving | running | working at 20 km / h in one Embodiment of this invention. The figure which shows the acceleration change of the X-axis direction at the time of driving | running | working at 40 km / h in one Embodiment of this invention. The figure which shows the acceleration change of the Z-axis direction at the time of driving | running | working at 2.5 km / h in one Embodiment of this invention. The figure which shows the acceleration change of the Z-axis direction at the time of driving | running | working at 20 km / h in one Embodiment of this invention. The figure which shows the acceleration change of the Z-axis direction at the time of the driving | running | working at 40 km / h in one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Vehicle, 2a-2d ... Tire, 3a-3d ... Wheel rotation motor, 4a-4d ... Axle, 5a-5d ... Sensor mounting plate, 6 ... Accel pedal, 7 ... Brake pedal, 8 ... Steering wheel, 100 ... Acceleration Sensor unit, 110 ... antenna, 120 ... antenna switch, 130 ... rectifier circuit, 131,132 ... diode, 133 ... capacitor, 134 ... resistor, 140 ... central processing unit, 141 ... CPU, 142 ... memory unit, 150 ... transmission 151, oscillation circuit, 152 ... modulation circuit, 153 ... high frequency amplification circuit, 160 ... sensor unit, 161 ... A / D conversion circuit, 200 ... reception unit, 210 ... radiation unit, 211 ... antenna, 212 ... transmission unit, 220 ... receiving unit, 221 ... antenna, 222 ... detection unit, 230 ... control unit, 240 ... calculation unit, 510 ... accelerator pedal depression angle detection sensor, 520 ... brake pedal depression angle detection sensor, 530 ... handle rotation angle detection sensor 540 ... Yo -Rate sensor, 620 ... Master cylinder, 630a-630d ... Pressure control valve, 640a-640d ... Brake drive actuator, 700 ... Drive control unit, 710 ... Control unit, 720 ... Motor drive unit, 730 ... Operating unit, 10 ... Semiconductor acceleration Sensor, 11 ... Base, 12 ... Silicon substrate, 13 ... Diaphragm, 13a-13d ... Diaphragm piece, 14 ... Thick film part, 15 ... Weight, 18A, 18B ... Support, 181 ... Outer frame part, 182 ... Post, 183 ... Beam, 184 ... Projection, 184a ... Projection tip, 31A-31C ... Voltage detector, 32A-32C ... DC power supply, Rx1-Rx4, Ry1-Ry4, Rz1-Rz4 ... Piezoresistor (Diffusion resistor) ).

Claims (7)

A control device for an electric vehicle equipped with a separate wheel rotation motor for each wheel,
A plurality of three-axis acceleration sensors that are attached to each wheel and that detect acceleration in the rotation direction of the wheel, acceleration in the rotation axis direction, and acceleration in a direction orthogonal to the rotation axis, and output information on each acceleration A sensor unit;
A turning angle setting means for setting a turning angle of the vehicle;
A yaw rate sensor that detects either the rotational speed or angular speed of the vehicle body relative to a predetermined vertical axis, and outputs the yaw rate information of the detection result;
A first depression angle detection sensor that detects a depression angle of an accelerator pedal and outputs information of the depression angle;
A second depression angle detection sensor that detects a depression angle of the brake pedal and outputs information of the depression angle;
The acceleration information output from the three-axis acceleration sensor, the turning angle information set by the turning angle setting means, the yaw rate information output from the yaw rate sensor, and the accelerator output from the first depression angle detection sensor Drive that performs pedaling angle information of the pedal and brake pedal depression angle information output from the second depression angle detection sensor and performs drive control of a wheel rotation motor that rotates each wheel based on the information. And an electric vehicle control apparatus. The said drive control means is provided with the means to increase the electric power supplied to the said wheel rotation motor in proportion to the depression angle detected by the said 1st depression angle detection sensor. Electric vehicle control device. Based on the turning angle information set by the turning angle setting means, the drive control means equalizes the amount of power supplied to the wheel rotation motors that rotate the left and right wheels when the set turning angle is 0 degrees. When the set turning angle is other than 0 degrees, the power supply amount to the wheel rotation motor on the turning direction side is set lower than the power supply amount to the wheel rotation motor on the opposite side to the turning direction. The electric vehicle control device according to claim 1, further comprising: means. When the turning angle set by the turning angle setting means is 0 degree, the drive control means is a wheel rotation motor that rotates the left and right wheels so as to reduce the rotational swing of the vehicle body based on the yaw rate information. The apparatus for controlling an electric vehicle according to claim 1, further comprising a means for adjusting a power supply ratio of the electric vehicle. The drive control means rotates the left and right wheels so that the acceleration in the rotation axis direction detected by the three-axis acceleration sensor becomes zero when the turning angle set by the turning angle setting means is 0 degree. The control device for an electric vehicle according to claim 1, further comprising means for adjusting a ratio of electric power supplied to the motor for rotation. The drive control means detects the number of rotations of the wheel per unit time from a change in acceleration value of either the acceleration in the rotation direction of the wheel detected by the three-axis acceleration sensor or the acceleration in the direction orthogonal to the rotation axis. The apparatus for controlling an electric vehicle according to claim 1, further comprising means for obtaining a vehicle traveling speed using the rotation speed. 2. The electric vehicle according to claim 1, wherein the drive control unit includes a unit that obtains a vehicle traveling speed based on an acceleration value in a direction orthogonal to the rotation axis detected by the three-axis acceleration sensor. Control device.

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