Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01V—GEOPHYSICS; GRAVITATIONAL MEASUREMENTS; DETECTING MASSES OR OBJECTS; TAGS
  • G01V3/00—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation
  • G01V3/02—Electric or magnetic prospecting or detecting; Measuring magnetic field characteristics of the earth, e.g. declination, deviation operating with propagation of electric current

Definitions

• Patent Document 1 The system disclosed in Patent Document 1 has multiple capacitance sensors inside the seat, and determines whether a person is seated on each sensor by comparing the capacitance values detected by those sensors with a threshold value.
• Patent Document 1 simply compares the capacitance value with a threshold value to determine whether a person is seated on each capacitance sensor. Therefore, if a person is not seated, i.e., if the person's body position is far from the capacitance sensor, the position of the person cannot be detected.
• This disclosure was made based on this situation, and its purpose is to provide a position detection device that can detect the position of a human body even when the human body is located away from the detection electrode that detects the capacitance value.
• One disclosure for achieving the above objective is a position detection device comprising one reference electrode, two or more detection electrodes, a measurement unit that measures capacitance-related values, which are either the capacitance value between the reference electrode and each detection electrode or a value that changes in relation to the capacitance value, and a position detection unit that detects the position of a human body based on the capacitance-related values measured by the measurement unit for each detection electrode.
• the reference electrode is common to two or more detection electrodes, and the measurement unit measures the capacitance value between the reference electrode and each detection electrode, or a capacitance-related value, which is a value that changes in relation to the capacitance value.
• the relative relationship between the magnitude of each capacitance-related value differs depending on the direction in which the human body position is away from the detection electrode. Therefore, the human body position can be detected with high accuracy even if the human body is located far away from the detection electrode used to detect the capacitance value.
• FIG. 1 is a diagram illustrating the configuration of a position detection device according to a first embodiment.
• FIG. 3 is a diagram showing the arrangement of detection electrodes.
• FIG. 2 is a diagram showing the configuration of a measurement unit.
• FIG. 10 is a diagram illustrating the relationship between the capacitance ratio and the foot position.
• FIG. 10 is a diagram showing the relationship between the capacitance ratio and the position of the foot in the vehicle width direction.
• FIG. 10 is a diagram showing an example of a position detection process.
• FIG. 10 is a diagram showing a position detection process executed by a position detection unit in the second embodiment.
• FIG. 10 is a diagram showing the relationship between the distance between the detection electrode and the foot and the capacitance value.
• FIG. 10 is a diagram showing the relationship between the distance between the detection electrode and the foot and the capacitance value.
• FIG. 10 is a diagram showing the configuration of a position detection device according to a fourth embodiment.
• FIG. 10 is a diagram illustrating a fifth embodiment.
• FIG. 13 is a diagram showing the configuration of a position detection device according to a sixth embodiment.
• FIG. 20 is a diagram showing a position detection process according to the sixth embodiment.
• FIG. 20 is a diagram illustrating a detection electrode according to the seventh embodiment.
• FIG. 20 is a diagram showing the arrangement of detection electrodes in the eighth embodiment.
• FIG. 1 is a diagram illustrating the configuration of a position detection device 100 according to this embodiment.
• the position detection device 100 is mounted on a vehicle 10.
• the position detection device 100 is configured to include a detection electrode 101, a reference electrode 103, a measurement unit 110, and a position detection unit 120.
• the reference electrode 103 is the body of the vehicle 10. Although the body of the vehicle 10 exists in various locations on the vehicle 10, if it can be considered to have the same potential, there is only one reference electrode 103.
• the detection electrodes 101 are respectively arranged on the accelerator pedal 11a and the brake pedal 11b of the vehicle 10.
• the detection electrode 101 arranged on the accelerator pedal 11a is referred to as detection electrode 101a
• the detection electrode 101 arranged on the brake pedal 11b is referred to as detection electrode 101b.
• Both detection electrodes 101a and 101b are flat. When there is no need to distinguish between the two detection electrodes 101a and 101b, they are referred to as detection electrodes 101. When there is no need to distinguish between the accelerator pedal 11a and the brake pedal 11b, they are referred to as pedals 11.
• the measurement unit 110 can apply an AC voltage to the detection electrode 101.
• the measurement unit 110 measures the capacitance value C between the detection electrode 101a and the reference electrode 103, and between the detection electrode 101b and the reference electrode 103.
• the reference electrode 103 When an AC voltage is applied to the detection electrode 101, the reference electrode 103, which is the body of the vehicle 10, becomes GND, and an electrical circuit is created that includes the detection electrode 101, the occupant P, and the metal parts inside the seat 12 of the vehicle 10.
• capacitance and resistance exist between the reference electrode 103 and the detection electrode 101, as indicated by symbols in Figure 1.
• the capacitance value C between the reference electrode 103 and the detection electrode 101a is the capacitance value Ca
• the capacitance value C between the reference electrode 103 and the detection electrode 101b is the capacitance value Cb.
• FIG. 3 shows the configuration of the measurement unit 110.
• the measurement unit 110 includes a current measurement unit 111, a detector 112, and a power supply 113.
• the measurement unit 110 can also be referred to as a measurement device or a measurement circuit.
• the current measurement unit 111 detects the amplitude and phase of the current flowing through the detection electrode 101, and can use a shunt resistor, for example.
• a current measurement unit 111 is provided for each of the multiple detection electrodes 101.
• the detector 112 detects current information and voltage information of the current flowing through the current measuring unit 111. This current information and voltage information include amplitude and phase. The detector 112 then calculates impedance or admittance based on the detected current information and voltage information. Furthermore, the detector 112 calculates a capacitance component from the calculated impedance or admittance. The value of the capacitance component calculated based on the current information and voltage information of the current measuring unit 111 corresponding to the detection electrode 101a is the capacitance value Ca, and the value of the capacitance component calculated based on the current information and voltage information of the current measuring unit 111 corresponding to the detection electrode 101b is the capacitance value Cb.
• the position detection unit 120 controls the measurement unit 110 to cause the measurement unit 110 to measure the capacitance values Ca and Cb.
• the position detection unit 120 also detects the human body position based on the capacitance values Ca and Cb measured by the measurement unit 110.
• the human body position detected is the position of the feet PF of the occupant P, which is a part of the human body.
• the feet PF are parts below the ankles.
• the position detection unit 120 can be realized, for example, by a computer equipped with a processor and memory.
• the position detection unit 120 is not limited to a computer, and may also be configured to include a hardware circuit that performs the following processing.
• the position detection unit 120 uses the two capacitance values Ca and Cb by calculating the ratio between the two capacitance values Ca and Cb.
• the ratio between the capacitance values Ca and Cb will be referred to as the capacitance ratio.
• Either the capacitance value Ca or Cb may be used as the denominator.
• the capacitance ratio Ca/Cb will be calculated using the capacitance value Cb as the denominator.
• FIG. 4 is a state in which the foot PF is located above and near the brake pedal 11b.
• (B) is a state in which the foot PF is located above and near the accelerator pedal 11a.
• (C) is a state in which the foot PF is located above the brake pedal 11b, but away from it.
• FIG. 5 shows the relationship between the capacitance ratio Ca/Cb and the position of the foot PF in the vehicle's width direction.
• (A), (B), and (C) represent the states (A), (B), and (C) in Figure 4, respectively.
• the capacitance ratio Ca/Cb is greatly affected by the position of the foot PF in the vehicle's width direction, i.e., the direction in which the detection electrodes 101 are arranged, and is hardly affected by the vertical position of the foot PF.
• the capacitance values Ca and Cb are also affected by differences in the material of the shoe sole. This is because the dielectric constant changes depending on the material of the shoe sole. However, by making it a ratio, differences in the material of the shoe sole are also canceled out.
• FIG 6 shows an example of position detection processing. This processing is performed by the position detection unit 120.
• the measurement unit 110 measures the capacitance value Ca and acquires this value.
• the measurement unit 110 measures the capacitance value Cb and acquires this value.
• the capacitance ratio Ca/Cb is calculated using the capacitance values Ca and Cb acquired in S10 and S20.
• the proximity threshold is a value used to determine whether a human body is present near the detection electrode 101 corresponding to the capacitance values Ca and Cb. In this embodiment, the proximity threshold is a fixed value determined in advance. If the capacitance values Ca and Cb are both equal to or less than the proximity threshold, the process proceeds to S50. In S50, it is determined that the foot PF, which is the detection target, is not present near the detection electrode 101.
• Position determination threshold TH1 is a threshold used to determine whether the foot PF is near the detection electrode 101b, i.e., near the brake pedal 11b.
• Position determination threshold TH2 is a threshold used to determine whether the foot PF is near the detection electrode 101a, i.e., near the accelerator pedal 11a. The specific values of position determination thresholds TH1 and TH2 are determined based on experiments, etc.
• the process proceeds to S70, where it is determined that the foot PF is near the brake pedal 11b. If the determination in S60 shows that the capacitance ratio Ca/Cb is greater than the position determination threshold TH1 and less than the position determination threshold TH2, the process proceeds to S80, where it is determined that the foot PF is between the brake pedal 11b and the accelerator pedal 11a. If the determination in S60 shows that the capacitance ratio Ca/Cb is greater than or equal to the position determination threshold TH2, the process proceeds to S90, where it is determined that the foot PF is near the accelerator pedal 11a.
• the notification method may be, for example, displaying the determination result on a specified display unit.
• the position detection device 100 of the first embodiment described above includes two detection electrodes 101 and a common reference electrode 103, and the measurement unit 110 measures the capacitance values Ca and Cb between the reference electrode 103 and each detection electrode 101 (S10, S20). As described with reference to Fig. 4, the relative relationship between the magnitudes of the capacitance values Ca and Cb varies depending on the direction in which the foot PF is separated from the detection electrode 101. Therefore, the position detection device 100 can accurately detect the position of the foot PF even if the foot PF is separated from the detection electrode 101.
• the body of the vehicle 10 serves as the reference electrode 103. Therefore, when installing the position detection device 100 in the vehicle 10, there is no need to prepare a separate reference electrode 103.
• the position detection unit 120 detects the position of the foot PF based on the capacitance ratio Ca/Cb (S60, S70, S80, S90).
• the capacitance ratio Ca/Cb is less affected by the vertical position of the foot PF and the material of the sole. Therefore, the position of the foot PF in the vehicle width direction can be detected with high accuracy.
• the position detection unit 120 determines whether the foot PF is near the detection electrode 101 based on the magnitudes of the capacitance values Ca and Cb used to calculate the capacitance ratio Ca/Cb (S40, S50). This improves the accuracy of detecting the position of the foot PF.
• the two detection electrodes 101a, 101b are provided on the accelerator pedal 11a and the brake pedal 11b. Therefore, when S50 in Figure 6 is executed, it can be determined that the foot PF is neither near the accelerator pedal 11a nor near the brake pedal 11b.
• Figure 7 shows the position detection process executed by the position detection unit 120 in the second embodiment.
• S10, S20, S30, and S40 are the same as in Figure 6.
• S50, S60, S70, S80, and S90 shown are also the same as in Figure 6.
• the process proceeds to S71.
• S71 the differential value of the capacitance value Cb is calculated.
• the pedal operation state is determined based on the differential value calculated in S71.
• the second state is when the depression state of the brake pedal 11b is maintained.
• the third state is when the depression amount of the brake pedal 11b is decreasing. These first to third states are when the detection electrode 101b and the brake pedal 11b are pressed down.
• the final fourth state is when the foot PF is not in contact with the brake pedal 11b.
• Figure 8 shows the relationship between the distance D between the detection electrode 101b and the foot PF and the capacitance value Cb when the detection electrode 101b is installed on the brake pedal 11b.
• the scale to the left of 0 on the horizontal axis represents the amount of operation of the brake pedal 11b.
• the amount of change in capacitance value Cb increases as distance D approaches 0 from a large state. This amount of change further increases as brake pedal 11b is operated.
• the first state i.e., when the amount of depression of brake pedal 11b is increasing, the absolute value of the derivative of capacitance value Cb increases.
• the third state i.e., when the amount of depression of brake pedal 11b is decreasing, the absolute value of the derivative of capacitance value Cb also increases.
• a pedal depression threshold is set based on experiments, etc., and a determination is made based on whether the absolute value of the derivative exceeds this pedal depression threshold.
• the absolute value of the differential value first exceeds the pedal depression threshold, it can be determined that the first state has been reached. Subsequently, as the change in the amount of depression decreases, such as when the brake pedal 11b is fully depressed, the change in the capacitance value Cb also decreases. Therefore, when the process of FIG. 7 is repeatedly executed and S70 is continuously executed, if the differential value of the capacitance value Cb falls below the pedal depression threshold after determining that the first state has been reached, it can be determined that the second state has been reached, i.e., the brake pedal 11b is still being depressed.
• the differential value has the opposite sign to when the first state was determined, but the absolute value of the differential value exceeds the pedal depression threshold, it can be determined that the third state has been reached, i.e., the amount of depression of the brake pedal 11b is decreasing. If the differential value then falls below the pedal depression threshold, it can be determined that the fourth state has been reached, i.e., the foot PF is not in contact with the brake pedal 11b.
• the process proceeds to S91.
• the differential value of the capacitance value Ca is calculated.
• the pedal operation state is determined based on the differential value calculated in S91.
• the pedal operation state is the four states determined in S72, but with the accelerator pedal 11a replaced, and there are four states as follows: The first state is when the depression amount of the accelerator pedal 11a is increasing. The second state is when the depression state of the accelerator pedal 11a is maintained. The third state is when the depression amount of the accelerator pedal 11a is decreasing. The fourth state is when the foot PF is not in contact with the accelerator pedal 11a.
• the pedal depression threshold is exceeded for the first time after it is determined that the foot PF is near the accelerator pedal 11a, it can be determined that the first state is in effect, i.e., the amount of depression of the accelerator pedal 11a is increasing.
• the pedal depression threshold is determined based on experiments, etc.
• the pedal depression threshold may be the same as or different from S72.
• the change in the capacitance value Ca also decreases. Therefore, when the process of FIG. 7 is repeatedly executed and S70 is continuously executed, if the differential value of the capacitance value Ca falls below the pedal depression threshold after determining that the first state is in effect, it can be determined that the second state is in effect, i.e., that the accelerator pedal 11a is being maintained in a depressed state. Furthermore, if the differential value has the opposite sign to when the first state was determined to be in effect, but the absolute value of the differential value exceeds the pedal depression threshold, it can be determined that the third state is in effect, i.e., that the amount of depression of the accelerator pedal 11a is decreasing. If the differential value then falls below the pedal depression threshold, it can be determined that the fourth state is in effect, i.e., that the foot PF is not in contact with the accelerator pedal 11a.
• the second embodiment it is possible to determine whether the foot PF is near the detection electrode 101 (S70, S90), and also to determine whether the detection electrodes 101b, 101a are being pressed down based on the differential values of the capacitance values Ca, Cb.
• the pedal operation state is determined based on the capacitance values Cb and Ca.
• the pedal operation state is determined based on the capacitance ratio Ca/Cb.
• the differential value of the capacitance ratio Ca/Cb is calculated instead of the differential value of the capacitance value Cb, and in S72, the pedal operation state can be determined based on the differential value of the capacitance ratio Ca/Cb.
• the differential value of the capacitance ratio Ca/Cb is calculated instead of the differential value of the capacitance value Ca, and in S92, the pedal operation state can be determined based on the differential value of the capacitance ratio Ca/Cb.
• Fourth Embodiment 9 shows the configuration of a position detection device 400 according to the fourth embodiment.
• a reference electrode 403 is disposed in the bottom portion 12a of the seat 12.
• the other configuration is the same as that of the position detection device 100.
• the distance between the occupant P and the reference electrode 103 changes when the occupant P approaches the door of the vehicle 10, for example. Therefore, in the first embodiment, the capacitance values Ca and Cb are easily affected by the posture of the occupant P.
• the reference electrode 403 is disposed in the seat portion 12a of the seat 12, so the distance between the occupant P and the reference electrode 403 remains stable regardless of the posture of the occupant P.
• This increases the correlation between the capacitance values Ca and Cb and the position of the foot PF. This improves the accuracy of the position of the foot PF detected based on the capacitance values Ca and Cb.
• FIG. 10 is a diagram illustrating the fifth embodiment.
• the fifth embodiment includes a guard electrode 502 near the detection electrode 101.
• the guard electrode 502 includes a voltage follower circuit 504 for applying the same potential as the detection electrode 101 to the guard electrode 502.
• the guard electrode 502 is provided for the purpose of preventing electric field lines from spreading to unnecessary areas, so that the capacitance values Ca and Cb measured by the measurement unit 110 become the capacitance value C of the portion where the occupant P is present between the detection electrode 101 and the reference electrode 103.
• the guard electrode 502 is provided in a direction from the detection electrode 101 toward the reference electrode 103 without passing through the occupant P.
• two guard electrodes 502 are provided, but the number of guard electrodes 502 can be adjusted as appropriate for the above purpose.
• the number of guard electrodes 502 may be one, or three or more.
• the correlation between the capacitance values Ca and Cb and the capacitance of the occupant P is increased, so that changes in the position of the feet PF, which are part of the occupant P, are more likely to affect the capacitance values Ca and Cb. This improves the accuracy of detecting the position of the feet PF based on the capacitance values Ca and Cb.
• Sixth Embodiment 11 shows the configuration of a position detection device 600 according to the sixth embodiment.
• the position detection device 600 includes the measurement unit 110, detection electrode 101, and reference electrode 403 described in the previous embodiments.
• the position detection device 600 also includes a press detection unit 610, a position detection unit 620, and an occupant identification unit 630.
• the depression detection unit 610 detects when the occupant P presses down on the pedal 11 on which the detection electrode 101 is located. Because the detection electrode 101 is located on the accelerator pedal 11a and the brake pedal 11b, the depression detection unit 610 detects when the accelerator pedal 11a and the brake pedal 11b are pressed down, respectively. The depression detection unit 610 detects when the pedal 11 is pressed down based on a characteristic value different from the capacitance values Ca and Cb.
• the depression of the accelerator pedal 11a can be determined based on a signal from an accelerator position sensor, for example.
• the depression of the brake pedal 11b can be determined based on a signal from a brake switch.
• the position detection unit 620 detects the position of the foot PF through the process shown in FIG. 12.
• proximity thresholds THa and THb are used.
• the position detection unit 620 adjusts the proximity thresholds THa and THb based on the capacitance values Ca and Cb measured by the measurement unit 110 when the depression detection unit 610 detects that the accelerator pedal 11a or the brake pedal 11b has been depressed.
• the proximity threshold THa is determined by multiplying the capacitance value Ca measured by the measurement unit 110 when the depression detection unit 610 detects that the accelerator pedal 11a has been depressed by a predetermined coefficient that is smaller than 1.
• the proximity threshold THb is determined by multiplying the capacitance value Cb measured by the measurement unit 110 when the depression detection unit 610 detects that the brake pedal 11b has been depressed by a predetermined coefficient that is smaller than 1.
• S210 and S220 are the same as S10 and S20 in Figure 6, and the position detection unit 620 causes the measurement unit 110 to measure the capacitance values Ca and Cb and acquires these values.
• S230 it is determined whether the capacitance value Ca obtained in S210 is equal to or less than the proximity threshold value THa, and whether the capacitance value Cb obtained in S220 is equal to or less than the proximity threshold value THb. If the determination result in S230 is YES, the process proceeds to S240. In S240, it is determined that there is no foot PF near the detection electrode 101.
• S250 it is determined whether the magnitude of the capacitance value Ca obtained in S210 is greater than the proximity threshold value THa. If the determination result in S250 is YES, proceed to S260. In S260, it is determined that the foot PF is near the accelerator pedal 11a.
• S270 it is determined whether the magnitude of the capacitance value Cb obtained in S220 is greater than the proximity threshold value THb. If the determination result in S270 is YES, proceed to S280. In S280, it is determined that the foot PF is near the brake pedal 11b.
• the occupant identification unit 630 identifies the occupant P based on the capacitance values Ca and Cb measured by the measurement unit 110.
• the occupant P is identified based on the correlation between the capacitance values Ca and Cb and the physique of the occupant P.
• the difference in capacitance values Ca and Cb is largely influenced by differences in the physique of the occupant P.
• the reference electrode 403 is provided on the bottom portion 12a of the seat 12, there is little change in capacitance values Ca and Cb due to changes in the posture of the occupant P.
• the depression detection unit 610 when it is possible to determine that the position of the foot PF relative to the pedal 11 is in a certain fixed state by the depression detection unit 610, it is possible to estimate, based on the capacitance values Ca and Cb measured by the measurement unit 110, whether the occupant P is one or more people whose capacitance values Ca and Cb have been detected in the past, or whether the occupant P is a person whose capacitance values Ca and Cb have not been detected in the past.
• the state of the foot PF relative to the pedal 11 may be, for example, a state in which the foot PF of the occupant P has started to press the pedal 11, or a state in which the foot PF of the occupant P has fully depressed the pedal 11. Furthermore, if a sensor is provided to detect the amount of depression of the accelerator pedal 11a and the brake pedal 11b, the state of the foot PF relative to the pedal 11 may be a state in which the pedal is depressed by a predetermined amount.
• the capacitance values Ca and Cb corresponding to the detection electrodes 101a and 101b are obtained (S210, S220), and the position of the foot PF is detected based on the magnitude of the capacitance values Ca and Cb for each detection electrode 101a and 101b (S230-S290).
• the position of the foot PF can also be detected based on the magnitude of the capacitance values Ca and Cb, rather than the capacitance ratio Ca/Cb.
• the position detection unit 620 adjusts the proximity thresholds THa and THb based on the capacitance values Ca and Cb when it detects that the accelerator pedal 11a or the brake pedal 11b has been pressed. This improves the accuracy of the determinations made in S230, S250, and S270, thereby improving the accuracy of detecting the position of the foot PF.
• the sixth embodiment includes an occupant identification unit 630 that identifies the occupant P based on the capacitance values Ca and Cb measured by the measurement unit 110 when the pedal 11 is pressed. Therefore, in addition to detecting the position of the occupant P's foot PF, the occupant P can also be identified.
• two detection electrodes 701 i.e., a detection electrode 701a arranged on the accelerator pedal 11a and a detection electrode 701b arranged on the brake pedal 11b, have different areas. Note that these detection electrodes 701a and 701b may be applied to the previous embodiments. Also, the detection electrodes 101a and 101b of the previous embodiments may have the same area.
• the capacitance value Cbo is free from the influence of the difference in the dielectric constant of the shoes of the occupant P, as described below.
• the capacitance value Ca can be expressed by Cfa and Cbo .
• Cfa is the capacitance value C between the foot PF and the detection electrode 101a arranged on the accelerator pedal 11a
• Cbo is the capacitance value C between the body of the occupant P and the reference electrode 103.
• the capacitance value Cb can be expressed by Cfb and Cbo .
• Cfb is the capacitance value C between the foot PF and the detection electrode 101b arranged on the brake pedal 11b. Furthermore, Cfa and Cfb can also be expressed by equations (3) and (4), respectively. In equations (3) and (4), ⁇ is the dielectric constant determined by the material of the shoe sole, d is the thickness of the shoe sole, S a is the area of the detection electrode 101 a, and S b is the area of the detection electrode 101 b.
• Equation (5) can be obtained from equations (3) and (4). Substituting equation (5) into equation (1) gives equation (6). Looking at equations (6) and (2), there are two unknowns, C fb and C bo , so the two unknowns, C fb and C bo, can be found from equations (6) and (2).
• the seventh embodiment by making the areas of the detection electrodes 101a and 101b different, it is possible to obtain Cbo that does not include Cfb . By using Cbo , the accuracy of identifying the occupant P is improved.
• detection electrodes 801 include detection electrodes 801a1, 801a2, 801b1, 801b2, and 801b3. Detection electrodes 801a1 and 801a2 are arranged on the accelerator pedal 11a. Detection electrodes 801b1, 801b2, and 801b3 are arranged on the brake pedal 11b.
• the capacitance value C between the detection electrode 801a1 and the reference electrode 103 and the capacitance value C between the detection electrode 801a2 and the reference electrode 103 is used as the capacitance value Ca. Furthermore, the sum of the capacitance values C between the detection electrodes 801b1, 801b2, and 801b3 and the reference electrode 103 is used as the capacitance value Cb. Then, using the processing described in the previous embodiments, it is determined whether the foot PF is near the accelerator pedal 11a or the brake pedal 11b.
• the size or ratio of the two capacitance values C between the detection electrodes 801a1 and 801a2 and the reference electrode 103 is used to determine which detection electrode 801a1 or 801a2 the foot PF is stepping on.
• the size of the capacitance values C it can be determined that the foot PF is more likely to be stepping on the detection electrode 801a1 or 801a2 with the larger capacitance value C.
• the ratio of the capacitance values C it can be determined that the larger the ratio, the more likely the foot PF is stepping on the detection electrode 801a1 or 801a2 corresponding to the capacitance value C used as the numerator.
• the size or ratio of the three capacitance values C between the detection electrodes 801b1, 801b2, and 801b3 and the reference electrode 103 is used to determine which of the detection electrodes 801b1, 801b2, and 801b3 the foot PF is stepping on.
• ratios three ratios are calculated. Two of the three ratios have the capacitance value C corresponding to one of the three detection electrodes 801b1, 801b2, and 801b3 as the denominator. For example, the capacitance value C corresponding to the detection electrode 801b1 is used as the denominator. The remaining one of the two ratios is the ratio of the capacitance values C corresponding to the detection electrodes 801b2 and 801b3, which were not used as the denominators in the previous two ratios.
• the accelerator pedal 11a and the brake pedal 11b are each provided with a plurality of detection electrodes 801a1, 801a2, 801b1, 801b2, and 801b3.
• the capacitance value C between each of the detection electrodes 801a1, 801a2, 801b1, 801b2, and 801b3 and the reference electrode 103 is calculated. In this way, it is possible to determine where on the pedal 11 the foot PF is stepping, or how the pedal 11 is being stepped on.
• the reference electrodes 103, 403 are provided on the body of the vehicle 10 or the seat portion 12a of the seat 12.
• the reference electrodes may be provided on the floor surface of the vehicle 10.
• the reference electrode 403 may be arranged near the feet of the driver's seat of the vehicle 10 so as to include an area where the left foot of the occupant P is placed.
• the reference electrode 403 may be provided on a footrest.
• the capacitance values Ca, Cb are less likely to be affected by the upper body posture of the occupant P.
• the reference electrode 403 is provided in the seat portion 12a of the seat 12.
• the reference electrode 403 may be provided in the backrest portion of the seat 12 instead of or in addition to the seat portion 12a of the seat 12.
• the reference electrode 403 provided in the seat portion 12a and the reference electrode 403 provided in the backrest portion are electrically connected to form a single reference electrode 403.
• the position of the human body is detected based on the capacitance value C.
• the detection electrodes 101, 701, and 801 are disposed on the pedal 11. However, the detection electrodes 101, 701, and 801 may be disposed on one or both of the steering wheel of the vehicle 10 and the operation panel surface of the vehicle 10. When the detection electrodes 101, 701, and 801 are disposed on the steering wheel of the vehicle 10 and the operation panel surface of the vehicle 10, the positions of the hands of the occupant P are to be detected.
• the accelerator pedal 11a and the brake pedal 11b each have a plurality of detection electrodes 801.
• the plurality of detection electrodes 801 may be disposed on a component other than the accelerator pedal 11a or the brake pedal 11b.
• the plurality of detection electrodes 801 may be disposed on only one of the accelerator pedal 11a or the brake pedal 11b.
• the number of detection electrodes 801 disposed on one component can be adjusted as appropriate based on the size, shape, etc. of the component.
• a position detection device comprising:
• the reference electrode (103) is the body of the vehicle (10).
• a position detection device according to Technical Idea 1. (Technical thought 3) The reference electrode (403) is provided on one or both of a seat portion (12a) and a backrest portion of a seat (12) of a vehicle (10).
• a position detection device according to Technical Idea 1. (Technical thought 4) The reference electrode is provided on the floor of the vehicle.
• a position detection device according to Technical Idea 1. (Technical Thought 5)
• a guard electrode (502) to which the same potential as the detection electrode is applied is provided.
• the position detection unit detects the position of the human body based on the magnitude of the capacitance-related value for each of the detection electrodes.
• a position detection device according to any one of technical concepts 1 to 5.
• the position detection unit detects the position of the human body based on the ratio of the capacitance-related values;
• a position detection device according to any one of technical concepts 1 to 5.
• the position detection unit determines whether or not a human body is located near the detection electrode corresponding to the capacitance-related value based on the magnitude of the capacitance-related value used in calculating the ratio of the capacitance-related values.
• a position detection device according to Technical Idea 7.
• the sensing electrode is disposed on a pedal (11) of a vehicle, the position detection unit determines whether a human body is located near the detection electrode disposed on the pedal based on the magnitude of the capacitance-related value used to calculate the ratio of the capacitance-related values.
• a position detection device according to Technical Idea 7. the position detection unit determines, based on a differential value of the capacitance-related value, whether or not the detection electrode corresponding to the capacitance-related value is being pressed by a human body.
• a position detection device according to any one of technical concepts 1 to 9.
• the position detection unit determines, based on a differential value of the ratio of the capacitance-related values, whether or not the human body is pressing down on the detection electrode corresponding to the capacitance-related value used to calculate the ratio of the capacitance-related values.
• a position detection device according to Technical Idea 7 or 8. (Technical Thought 12) The sensing electrode is disposed on a pedal (11) of a vehicle. A position detection device according to any one of technical concepts 1 to 8 and 11.
• a depression detection unit (610) that detects that the pedal has been depressed based on a characteristic value different from the capacitance-related value; and adjusting a threshold value for determining the position of the human body based on the capacitance-related value measured by the measurement unit while the depression detection unit detects that the pedal is depressed.
• a position detection device according to Technical Idea 12.
• the detection electrode is disposed on at least one of a steering wheel of a vehicle and an operation panel surface of the vehicle.
• a position detection device according to any one of technical concepts 1 to 9.
• a plurality of the detection electrodes (801) are arranged on one member that determines whether a human body is in contact with the member.
• a position detection device according to any one of technical concepts 1 to 14.
• (Technical Thought 16) an occupant identification unit (630) that identifies an occupant based on the capacitance-related value measured by the measurement unit while the pedal is pressed;
• a position detection device according to any one of technical concepts 9, 12, and 13.
• the reference electrode (403) is provided on the seat portion (12a) of the vehicle seat, The detection electrode is provided on a pedal (11) of the vehicle, an occupant identification unit (630) that identifies an occupant based on the capacitance-related value measured by the measurement unit while the pedal is pressed;
• a position detection device according to Technical Idea 1.
• a plurality of the detection electrodes are provided on a plurality of pedals of the vehicle, respectively, and the areas of the plurality of the detection electrodes are different from one another; the occupant identification unit identifies the occupant based on the capacitance-related values measured by the measurement unit while each of the plurality of pedals is pressed down. 18.
• a position detection device according to Technical Idea 16 or 17.

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• 2024
  • 2024-05-28 JP JP2024086539A patent/JP2025179647A/ja active Pending
• 2025
  • 2025-05-15 WO PCT/JP2025/017721 patent/WO2025249195A1/ja active Pending

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