JPH05310130A - Steering wheel - Google Patents

Abstract

PURPOSE:To detect an information of driver's steering operation before the driver rotates a steering wheel. CONSTITUTION:In a steering wheel having a plurality of pressure sensors embedded in a ring portion 2 and intended to sense the pressure of the hand palm gripping the ring portion 2, the pressing force sensed by the pressure sensors 10 is set as a steering-wheel rotation start estimation signal. The pressing forces of the right/left pressure sensors 10 of the ring portion 2 are, on the other hand, used as a rotational-direction estimation signal for judging the rotational direction of the steering wheel to thereby enhance the responsiveness of a control system required to be controlled.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention has a pressure sensor arranged in a ring portion of a steering wheel, and in particular,
The present invention relates to a steering wheel that detects an external force applied to a ring portion.

[0002]

2. Description of the Related Art Some conventional steering wheels of this type have an air layer formed over substantially the entire ring portion to detect an external force applied to the ring portion. In addition, the electrodes are arranged on almost the entire ring portion of the steering wheel,
Some have detected that a hand is placed on the ring portion of the steering wheel by short-circuiting the electrodes by hand.

These steering wheels are mainly
It is used as a detector for a drowsiness prevention device and generates an alarm output depending on the difference from normal normal operation. Specifically, for example, the technique disclosed in Japanese Utility Model Laid-Open No. 53-84841 has two electrodes which are mounted on a steering wheel of a vehicle which is constantly operated by the driver's hand while the vehicle is traveling and which touches the driver's hand. And a circuit for detecting the differential value of the current flowing between the electrodes via the driver's hand, and a circuit for detecting that the differential value detected by the detection circuit is below a predetermined level for a certain period of time and outputting a signal. And an alarm device that operates with the output signal of the circuit, and is used as a drowsy driving alarm device.

[0004]

As described above, the conventional drowsiness driving warning device detects the external force applied to the ring portion by the air layer of the ring portion and is mounted on the steering wheel of the vehicle. Dozing is determined by the change in resistance between the two electrodes. However, the judgment of the external force applied to the ring portion or the judgment of the resistance value between the two electrodes changes depending on the grip pressure, the electric conductivity of the skin surface, the resistance value peculiar to each person, etc. Therefore, it is not always satisfactory to detect the driving condition of the driver.

On the other hand, in the technical field of electronic control of a vehicle, in the control of power steering, active electronic control suspension, etc., due to the limit of the response speed of the actuator, for example, in power steering, a clutch is applied to a system for applying assist torque. However, even if a relay for opening and closing the motor drive power source is provided, the clutch is engaged at the same time as the ignition switch is turned on, and the motor drive power source is turned on. The clutch configured to improve reliability and open / close control of the power source for driving the electric motor have not been sufficiently utilized in failsafe.

For example, a known electronic control circuit for driving and controlling an electric power steering apparatus is as shown in FIG.

FIG. 6 is a circuit diagram of an electronic control circuit for controlling a conventional electric power steering system.

The microcomputer CPU is composed of a one-chip microcomputer.
It contains OM, RAM, timer, counter, etc. The power is supplied from a constant voltage circuit (not shown). To the input of the microcomputer CPU, the pulse number output of the vehicle speed sensor SS including a permanent magnet that rotates according to the vehicle speed, a reed switch, a resistor, and the like is input after waveform shaping. Further, the output of the torque sensor TS including a strain detecting element is input to the microcomputer CPU via an amplifier and a control compensating circuit for compensating the proportional / integral / differential control constants.

On the other hand, the output of the microcomputer CPU is connected to the relay RY via the relay drive circuit DR3. Therefore, the microcomputer CP
When the relay output of U is "1", the relay RY is excited and its contact ry is closed. When it is "0", the relay RY can be de-energized to open its contact ry. Therefore, if the relay RY is de-energized, the contact ry can be opened and the rotation of the electric motor M can be stopped regardless of the later-described left signal, right signal, and PWM signal (ratio of the output of the duty ratio signal). Yes, it can have fail-safe support.

Further, the output of the microcomputer CPU is connected to the coil of the clutch mechanism CL via the clutch drive circuit DR5, and when the relay output of the microcomputer CPU is "1", the clutch mechanism CL.
Is in a coupled state, and when it is "0", it is in a released state.

The transistor Q1 and the base resistor R1 form a switching circuit, and the microcomputer CPU
The left signal "1" turns on the transistor Q1 via the drive circuit DR1, and the left signal "0" turns off the transistor Q1. Similarly, the transistor Q2 and the base resistor R2 form a switching circuit,
The right signal "1" of the microcomputer CPU turns on the transistor Q2 via the drive circuit DR1.
Further, the transistor Q2 is turned off by the right signal "0".

The transistor Q3 and the base resistor R3 form a switching circuit. When the PWM signal of the microcomputer CPU is "1", the transistor Q3 is turned on via the drive circuit DR2, and when the PWM signal is "0". The transistor Q3 turns off. Similarly, the transistor Q4 and the base resistor R4 form a switching circuit, and the PWM of the microcomputer CPU is
The signal "1" turns on the transistor Q4 via the drive circuit DR2, and the PWM signal "0" turns off the transistor Q4. Therefore, the electric motor M
When the transistor Q1 is turned on by a left signal "1" or the transistor Q2 is turned on by a right signal "1", the transistor Q1 rotates left or right according to the PWM signal of the microcomputer CPU. The diodes D1 to D4 are for flywheels for preventing the transistors Q1 to Q4 from being destroyed.

The microcomputer CPU of the electric power steering system of the present embodiment thus constructed is program-controlled as follows.

FIG. 7 is a flowchart of a main program for controlling the conventional electric power steering.

First, the program is started by turning on the ignition switch IG, and in step S1, the RAM and timer built in the microcomputer CPU are cleared and each output port is initialized. That is, the memory for storing the vehicle speed is cleared, the input of the clutch drive circuit DR5 is set to "0" to release the clutch mechanism CL, the input of the relay drive circuit DR3 is set to "0", and the relay RY is turned off, the drive circuit DR1 and the drive circuit DR2. Is set to "0". The clutch mechanism CL is engaged in step S2, the relay RY is excited via the relay drive circuit DR3 in step S3, and the contact ry is closed. In step S4, vehicle speed data is input from the vehicle speed sensor SS, the current vehicle speed is calculated, and the vehicle speed is stored in the memory. Step S
At 5, the output of the torque sensor TS is input, and the output of the torque sensor TS at that time is stored in the memory together with the information on the rotation direction. From the output of the torque sensor TS stored in the memory in step S6, the duty ratio output which is the PWM signal supplied to the electric motor M is calculated, and the output value is determined.

Then, in step S7, a duty ratio signal which is a PWM signal supplied to the electric motor M is output. The PWM signal determined in step S7, that is, the duty ratio and the leftward or rightward rotation direction is output, and thereafter, the routine processing of steps S4 to S7 is continued. In addition, the rotation direction of the electric motor M is output using the polarity of the output of the torque sensor TS stored in the memory. As a result, the assist torque required for steering is supplied according to the steering torque applied by the driver to the steering wheel.

In the power steering constructed as described above, the relay RY is de-excited to open the contact ry, and the rotation of the electric motor M can be stopped regardless of the left signal, the right signal and the PWM signal. The clutch mechanism CL is released by setting the input of the clutch drive circuit DR5 of the microcomputer CPU to "0", but the power steering of this type is temporarily operated by the ignition switch IG. When the program is started by turning on, the relay RY is in an excited state so that the rotation of the electric motor M is always enabled regardless of the left signal, the right signal and the PWM signal. Similarly, the clutch mechanism CL is in the engaged state,
Unless the microcomputer CPU positively detects an abnormal state, the power of the electric motor M cannot be cut off or the clutch mechanism CL cannot be released even when the steering wheel is not rotated.

Therefore, an object of the present invention is to provide a steering wheel capable of detecting steering information performed by a driver before turning the steering wheel.

[0019]

A plurality of steering wheels according to the invention of claim 1 are embedded in a ring portion,
A pressure sensor that detects the pressure of the palm that grips the ring portion is provided, and the pressing force of the pressure sensor is used as a rotation start prediction signal of the steering wheel.

A steering wheel according to a second aspect of the present invention has a plurality of pressure sensors embedded in the ring portion and having a pressure sensor for detecting the pressure of the palm holding the ring portion, and the pressing force of the pressure sensors on the left and right of the ring portion. Is used as a turning direction prediction signal for determining the turning direction of the steering wheel.

[0021]

According to the invention of claim 1, a plurality of pressure sensors are embedded in the ring portion and detect the pressure of the palm holding the ring portion. When the pressure sensor detects a predetermined pressing force or more, This signal is used to predict the start of rotation of the steering wheel. That is, immediately before the rotation of the steering wheel is applied, the actuator can be driven from the initial stage when the necessary conditions for entering the preparation system for the control to be performed next are complete, and the response can be improved.

According to the second aspect of the present invention, a plurality of pressure sensors are embedded in the ring portion and detect the pressure of the palm holding the ring portion, and the pressing force of the palm holding the ring portion is applied to the left and right of the ring portion. The turning direction of the steering wheel is determined by the pressure sensors to detect the turning direction of the steering wheel based on the magnitude of the left and right pressure sensors, and the turning direction is predicted based on the magnitude of the pressing force of the palm gripping the ring portion. That is, immediately before the rotation of the steering wheel is applied, the actuator can be driven from the initial stage when the necessary conditions for entering the preparation system for the control to be performed next are complete, and the response can be improved.

[0023]

EXAMPLES Examples of the present invention will be described below.

FIG. 1 is a plan view of an essential part of a ring portion of a steering wheel according to an embodiment of the present invention.

In the figure, the steering wheel body 1
As is well known, has a pad portion 4 that covers the ring portion 2, the spoke portion 3, and the boss portion based on the core metal 5.
The steering wheel body 1 used in this embodiment
Are not necessarily limited to those having the cored bar 5, and the product has the cored bar 5, but a steering wheel without the cored bar 5 can also be used in this case. The synthetic resin layer 6 is formed of vinyl chloride or is formed of a material known as a steering wheel such as integral skin urethane foam. Further, a skin layer 7 made of synthetic leather is formed on the outer periphery of the synthetic resin layer 6. The skin layer 7 is subjected to color and surface treatment according to the user's preference. An adhesive is used for joining the skin layers 7, and they are firmly integrated.

A pressure sensor 10 made of a known semiconductor pressure sensor, pressure-sensitive conductive rubber, or the like is provided at a predetermined required position on the ring portion 2 on the pad-side surface and the non-pad-side surface of the synthetic resin layer 6. It is set up. In this embodiment, the pressure sensors 10 composed of a plurality of semiconductor pressure sensors and the like are arranged in rows. Here, a plurality of pressure sensors 10 arranged on the outer peripheral side of the ring portion 2 located on the side opposite to the driver side, a group A, a plurality of pressure sensors 10 arranged on the back side of the ring portion 2 are group C, the ring portion 2 A plurality of pressure sensors 10 arranged between the groups A and C will be referred to as group B. However, in the case of the description of identifying the pressure sensor 10 on the right side of the steering wheel, the “right side pressure sensor 10R” and the left side pressure sensor 10
In the case of the description that specifies "left pressure sensor 10L",
"Pressure sensor 10RA" for specifying the pressure sensor 10 of the group A, "pressure sensor 10RC" for specifying the pressure sensor 10 of the group C, pressure sensor 10 for the group B
Is specified as “pressure sensor 10RB”.

The pressure sensor 10 is constructed as shown in FIG. FIG. 2 is a position explanatory view of the ring portion 2 of the steering wheel according to the embodiment of the present invention.
The presence of the individual R pressure sensors 10 is shown. The arrangement of the left side pressure sensor 10L is the symmetrical position in FIG. 2, and therefore its illustration is omitted.

First, the core metal of the target steering wheel body 1 is loaded into a mold, a synthetic resin layer 6 is formed by injection molding, and at the same time, a predetermined number of insertion holes 8 are formed at predetermined positions. Keep it. At this time, the place where the insertion hole 8 is formed is
For example, the driver's hand is usually determined by the position of the hand, but at the center of the ring portion 2, at least the left and right sides are divided into two groups. A pressure sensor 10 is inserted therein, a lead wire 11 is inserted in a lead wire insertion groove 9 formed along the outer circumference of the ring portion 2, and an end portion of the lead wire 11 is built in the pad portion 4 microcomputer CPU It leads to a control circuit equipped with etc. and performs a predetermined signal processing. Then, the ring portion 2 and the pressure sensor 1
On the outer periphery of 0, a skin layer 7 made of synthetic leather, which is subjected to color and surface treatment according to the user's preference, is formed.

The output of the pressure sensor 10 arranged on the ring portion 2 of the synthetic resin layer 6 is as follows.

The right pressure sensors 10R arranged in three rows are
As shown in the output ratio characteristic diagram of the right pressure sensor 10R in the right lane change test at the vehicle speed of 60 km / h in the present embodiment of FIG. 3A and the output characteristic diagram of the right pressure sensor 10R in the present embodiment of FIG. 3B. Become.

That is, generally, the pressure sensor 10RA of the group A is used.
The output of the pressure sensor 1 of the group B is generated because the gripping force is generated by the force held by the finger with respect to the palm.
It is larger than the output of the pressure sensor 10RC of 0 RB and C group. However, the pressure sensor 10RB of the B group is located between the pressure sensor 10RA of the A group and the pressure sensor 10RC of the C group, and depending on the individual difference or the position of the palm or the position of the finger, the pressure sensors 10RA and C of the A group. Group pressure sensor 1
Although it is assumed that the output will be larger than the output of 0RC, according to the experiments by the inventors, the output of the pressure sensor 10RC of the group C> the output of the pressure sensor 10RB of the group B> the output of the pressure sensor 10RA of the group A It did not upset the relationship.

The outputs of the pressure sensor 10RA of the group A, the pressure sensor 10RB of the group B, and the pressure sensor 10RC of the group C have different waveforms depending on the driver, but basically the actual steering angle is different. The phase is advanced by 1/4 cycle (1 second) from the waveform of.

This type of steering wheel can be used as a power steering as follows.

FIG. 4 is a circuit diagram of electronic control means for driving and controlling an electric power steering apparatus using a steering wheel according to an embodiment of the present invention. In the figure, the same reference numerals and symbols as those of the conventional example indicate the same or corresponding components as those of the present embodiment.
A duplicate description will be omitted.

The difference between this embodiment and the conventional example is that the pressure sensor 10RA of the group A on the right side and the pressure sensor 10R of the group B on the right side.
A circuit for introducing the outputs of the pressure sensors 10RC of the B and C groups to the microcomputer CPU via an amplifier circuit (not shown) is referred to as a right side pressure sensor RP, and a left side pressure sensor of the A group, a B group pressure sensor, and a C group. The output of the pressure sensor of FIG.
The circuit configuration is such that the circuit introduced into U is the left side pressure sensor LP and is input to the microcomputer CPU.

This power steering is controlled as follows by a control circuit including a microcomputer CPU and the like.

FIG. 5 is a flow chart of a control program executed by the microcomputer CPU of the power steering according to this embodiment.

In the figure, initialization is performed in step S11, vehicle speed input processing is performed by the output of the vehicle speed sensor SS in step S12, and it is determined in step S13 whether there is torque output from the torque sensor TS.

When the torque output of the torque sensor TS is present in step S13, the routine directly starts from step S18. When the torque output of the torque sensor TS is not present, it is determined in step S14 whether there is a rotation start prediction signal. If there is no rotation start prediction signal, step S1
In step 5, the PWM signal is set to "0", the transistors Q3 and Q4 are turned off, the right or left rotation direction signal is set to "0" or "1", and either the transistor Q1 or the transistor Q2 is turned on. Then, in step S16, the input of the clutch drive circuit DR5 is set to "0" to release the clutch mechanism CL, and in step S17.
Then, the input of the relay drive circuit DR3 is set to "0", the relay RY is turned off, and the steps S12 to S1 are performed.
The routine of 7 is repeatedly executed.

Although the torque output of the torque sensor TS is not generated in step S13, when the rotation start prediction signal is output in step S14, the input of the clutch drive circuit DR5 is set to "1" in step S18 and the clutch mechanism C is output.
Combine L, relay drive circuit DR3 in step S19
Is set to "1", the relay RY is turned on, the torque output applied by the output of the torque sensor is determined in step S20, and when there is no torque output, the routine of steps S12 to S14 and steps S18 to S20 is performed. Is repeatedly executed.

Then, in step S20, the torque sensor T
When it is confirmed that the output of S is generated, in step S21, the duty ratio output which is the PWM signal supplied to the electric motor M is calculated according to the vehicle speed and the magnitude and direction of the steering torque of the torque sensor TS, and the output value is determined. To do. Step S
Based on the calculation of the assist torque at 22, the assist torque is output by setting the PWM signal and the right or left rotation direction signal to "0" or "1". The same operation is performed when the output of the torque sensor TS is confirmed in step S13.

As described above, the steering wheel according to the embodiment of the present invention is a steering wheel having a plurality of pressure sensors 10 embedded in the ring portion 2 and detecting the pressure of the palm gripping the ring portion 2. 10
The pressing force detected by is used as a turning start prediction signal of the steering wheel.

Therefore, as in the case of the power steering of the above-described embodiment, it is possible to detect the time immediately before the driver turns the steering wheel, so that it is possible to secure the time to start the preparatory operation for outputting the assist torque before outputting the assist torque. The time required for opening and closing the circuit and the engagement / disengagement of the clutch mechanism, which are set for fail-safe, can be sufficiently taken, and the reliability of the power steering can be improved. Also, when the power steering is not functioning and is unnecessary, the function as the power steering device can be released and can be used as a manual steering mechanism, so by the way, an abnormality not detected by the abnormality detection circuit occurs. However, those effects can be released when the function as the power steering is not used.

That is, according to this embodiment, the coupling relationship with the steering wheel is generated electrically and mechanically only while the power steering is functioning.
As long as the steering wheel is not rotated, it functions as manual steering, and the control system and mechanism system that function as power steering can be released, so that the device can be made fail-safe. In addition, it is possible to secure a time for starting the preparatory operation for outputting the assist torque before outputting the assist torque, and improve the responsiveness.

The rotation start prediction signal is generated by the pressure sensors 10R and 10L on the left and right sides of the ring portion 2, and the right pressure sensor 10 is rotated rightward or leftward.
Since an output difference occurs between R and the left side pressure sensor 10L, and a large output is generated in the direction in which the left side pressure sensor 10L is being rotated, the pressing force of the right side pressure sensor 10R and the left side pressure sensor 10L on the left and right of the ring portion 2 is generated. The direction of rotation can also be determined by the difference between Therefore, if the difference between the pressures of the pressure sensors 10R and 10L on the left and right of the ring portion 2 is used as the rotation direction prediction signal, the preparatory operation for rotation, that is, the right or left rotation direction signal in the case of the power steering described above. It can be "0" or "1" and either the transistor Q1 or the transistor Q2 can be turned on. In this case, the assist torque can be adjusted only by the pulse width of the PWM signal rather than using the rotation start prediction signal, so that the responsiveness can be further improved.

As a matter of course, as the rotation start prediction signal and / or the rotation direction prediction signal, only one signal can be used, but both signals can also be used.

The turning start prediction signal and / or the turning direction prediction signal in the above embodiment has been described in the case of being used in the power steering device. However, in the case of implementing the present invention, the power steering is performed. As with the device, it can also be a control signal for an active electronically controlled suspension that is affected by the rotation of the steering wheel. It can also be used as a four-wheel steering control signal or a four-wheel drive control signal. In either case, it is possible to control the vehicle height, the turning angle of the wheels, the number of revolutions of each wheel, etc., which are caused by the change in the steering angle of the steering wheel.

By the way, the steering wheel according to the above-described embodiment includes the pressure sensor 10RA of the A group on the right side, the pressure sensor 10RB of the B group, the pressure sensor 10RC of the C group, and the pressure sensors of the A group and B group on the left side. In the embodiment of the present invention, one or a plurality of pressure sensors 10 are arranged linearly or in a matrix at a position where the driver normally grips with the palm. It suffices to dispose it, and it may be a position where the driver stochastically holds it with the palm and a position where the pressing force of the driver can be strongly detected.

By using the turning start prediction signal and / or the turning direction prediction signal of the above embodiment as a power steering control signal, the response of the power steering control can be improved. .. Further, by using the control signal of the active electronically controlled suspension, the control response of the active electronically controlled suspension can be improved. The response of the four-wheel steering control can be improved by using the four-wheel steering control signal. Furthermore, by using the control signal for four-wheel drive, the responsiveness of four-wheel drive control can be improved.

[0050]

As described above, the steering wheel according to the invention of claim 1 is a steering wheel having a plurality of pressure sensors embedded in a ring portion for detecting the pressure of the palm gripping the ring portion. The pressing force detected by is used as a turning start prediction signal of the steering wheel. Therefore, it is possible to detect the time immediately before the driver rotates the steering wheel, so that it is possible to secure a time for the preparation operation before the start of steering for the change in the steering angle for rotating the steering wheel, and the control system corresponding to the change in the steering angle can be secured. The responsiveness of can be improved.

A steering wheel according to a second aspect of the present invention is a steering wheel having a plurality of pressure sensors embedded in a ring portion for detecting the pressure of the palm gripping the ring portion, the left and right sides of the ring portion detected by the pressure sensor. It is used as a turning direction prediction signal for judging the turning direction of the steering wheel based on the pressing force of the pressure sensor. Therefore, since the direction of rotation can be detected immediately before the driver turns the steering wheel, a change in the steering angle for turning the steering wheel can be secured for the time to enter the preparatory operation before the start of steering, and the steering angle can be changed. The responsiveness of the control system can be improved.

[Brief description of drawings]

FIG. 1 is a plan view of an essential part of a ring portion of a steering wheel according to an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part of a ring portion of a steering wheel according to an embodiment of the present invention.

FIG. 3 (a) is an output ratio characteristic diagram of the right side pressure sensor in the right lane change test in the steering wheel of the embodiment of the present invention, and FIG. 3 (b) is an output characteristic diagram of the same right side pressure sensor.

FIG. 4 is a circuit diagram of electronic control means for driving and controlling an electric power steering apparatus using a steering wheel according to an embodiment of the present invention.

FIG. 5 is a flowchart of a control program executed by the microcomputer CPU of the power steering according to the embodiment of the present invention.

FIG. 6 is a circuit diagram of an electronic control circuit for controlling a conventional electric power steering system.

FIG. 7 is a flowchart of a main program for controlling a conventional electric power steering system.

[Explanation of symbols]

 1 Steering Wheel Main Body 2 Ring Part 10 Pressure Sensor 10RA A Group Pressure Sensor 10RB B Group Pressure Sensor 10RC C Group Pressure Sensor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Chiharu Totani 1 Ochiai, Nagahata, Kasuga-cho, Nishikasugai-gun, Aichi Toyoda Gosei Co., Ltd. Toyoda Gosei Co., Ltd.

Claims (2)

[Claims] 1. A steering wheel having a plurality of pressure sensors embedded in a ring portion for detecting the pressure of a palm gripping the ring portion, wherein the pressing force detected by the pressure sensor is used as a rotation start prediction signal of the steering wheel. A steering wheel characterized by: 2. A steering wheel having a plurality of pressure sensors embedded in a ring portion for detecting the pressure of a palm gripping the ring portion, wherein the pressure sensors detect the pressure of the pressure sensors on the left and right sides of the ring portion. A steering wheel, which uses a turning direction prediction signal for determining a turning direction of a steering wheel.