Contact determination device and contact determination method

Abstract

This invention provides a contact determination device and a contact determination method that can detect the removal of a hand from an object even when the hand is slowly removed, while also being able to compensate for a reference value corresponding to temperature changes during contact. The contact determination device includes: a sensor that measures the degree of contact between a detected object and an object and outputs a detection value corresponding to the degree of contact; a contact determination unit that determines whether a detected object is in contact with an object based on a reference value and the detection value used in determining whether the detected object is in contact with the object; and a correction unit that corrects the reference value. During the period when the contact determination unit determines that the detected object is in contact with the object, the correction unit, in accumulating the cumulative value of the change in the detection value since the start of contact, corrects the reference value based on the maximum value when the detection value increases corresponding to an increase in the degree of contact, or based on the minimum value when the detection value decreases corresponding to an increase in the degree of contact.

Description

Technical Field

[0001] This invention relates to a contact determination device and a contact determination method. Background Technology

[0002] Conventionally, there is an input device that detects at least one of contact with an operating body and proximity of the operating body. This input device includes: a measuring unit that measures a physical quantity corresponding to the operation; a determining unit that determines an operation state, including an operation state and a no-operation state, based at least on a base value and the physical quantity; and a base value updating unit that updates the base value during the operation period when the operation state is the "operation state," using the physical quantity whose change over a given time interval is within a given range. The determining unit determines the operation state based on the difference between the physical quantity and the base value (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent documents

[0005] Patent Document 1: JP 2016-218506

[0006] However, in existing input devices, since the base value follows the physical quantity, for example, when slowly changing from an operational state to a non-operational state by gradually removing the hand as the operator, the base value decreases accordingly as the physical quantity decreases. Therefore, the difference between the physical quantity and the base value in the non-operational state may increase to some extent, potentially leading to a misjudgment of an operational state. This is because existing input devices do not consider the scenario of slowly removing the hand.

[0007] Furthermore, since physical quantities tend to increase with rising temperature, the base values ​​need to be corrected as the temperature increases. Summary of the Invention

[0008] Therefore, the object of the present invention is to provide a contact determination device and a contact determination method that, while providing a correction corresponding to a reference value corresponding to temperature changes during contact, can detect the removal of a hand from an object even when the hand is slowly removed.

[0009] Methods for solving problems

[0010] The contact determination device according to an embodiment of the present invention includes: a sensor that measures the degree of contact between a detected object and an object and outputs a detection value corresponding to the degree of contact; a contact determination unit that determines whether the detected object is in contact with the object based on a reference value used in determining whether the detected object is in contact with the object and the detection value; and a correction unit that corrects the reference value. During the period when the contact determination unit determines that the detected object is in contact with the object, the correction unit corrects the reference value based on the maximum value of a cumulative value obtained by accumulating the change in the detection value from the start of contact between the detected object and the object, if the detection value increases as the degree of contact increases, or if the detection value decreases as the degree of contact increases, the correction unit corrects the reference value based on the minimum value of the cumulative value.

[0011] Invention Effects

[0012] It can provide a contact detection device and a contact detection method, and can compensate for the reference value corresponding to the temperature change during contact, while also detecting the situation where the hand is slowly removed from the object. Attached Figure Description

[0013] Figure 1 This is a diagram showing a steering wheel 10 equipped with the contact determination device 100 of the embodiment.

[0014] Figure 2 This is a diagram showing an example of the output sine wave of the electrostatic sensor 110.

[0015] Figure 3 This diagram illustrates the determination of contact using a reference value.

[0016] Figure 4 This is a flowchart representing the contact determination process performed by the MPU120B.

[0017] Figure 5 This is a flowchart representing the contact determination process performed by the MPU120B.

[0018] Figure 6 This is a flowchart representing the contact determination process performed by the MPU120B.

[0019] Figure 7 This is a flowchart representing the contact determination process performed by the MPU120B.

[0020] Figure 8 This is a diagram illustrating the operation of the contact determination device 100.

[0021] Figure 9 This is a diagram illustrating the operation of the contact determination device 100.

[0022] Figure 10 This is a diagram illustrating the operation of the contact determination device 100.

[0023] Figure 11 This is a diagram illustrating the operation of the contact determination device in the comparative example.

[0024] Figure 12 This is a diagram illustrating the operation of the contact determination device in the comparative example.

[0025] Figure 13 This is a diagram illustrating the operation of the contact determination device in the comparative example.

[0026] Figure 14 This is a diagram illustrating the operation of the contact determination device 100 in a modified embodiment.

[0027] Explanation of reference numerals in the attached figures

[0028] 10. Steering wheel

[0029] 11. Handle

[0030] 12 signal lines

[0031] 50 ECU

[0032] 100 Contact Detection Device

[0033] 110 Electrostatic Sensor

[0034] 120 HODECU

[0035] 120A AFE

[0036] 120B MPU

[0037] 121 Main Control Unit

[0038] 122. Correction Section

[0039] 123 Contact Determination Section

[0040] 124 memory Detailed Implementation

[0041] The following describes embodiments of the contact determination device and contact determination method using the present invention.

[0042] <Implementation Method>

[0043] Figure 1 This is a diagram showing a steering wheel 10 equipped with the contact determination device 100 of the embodiment. (See diagram below.) Figure 1As shown, the steering wheel 10, as an example, is mounted in a vehicle, and an electrostatic sensor 110 of a contact determination device 100 is installed inside the grip 11. The contact determination device 100 determines whether the driver's hand H is in contact with the grip 11 of the steering wheel 10.

[0044] For general purposes, the driver of the vehicle will be referred to as the operator of the contact determination device 100. The contact determination device 100 is not limited to... Figure 1 The purpose of assembling it onto the steering wheel 10 as shown is explained below. The contact determination device 100, which can determine whether the operator's hand H, which is the object being detected, has come into contact with an object equipped with an electrostatic sensor 110, will be described below. The operator's action is defined as the operator touching the object equipped with the electrostatic sensor 110.

[0045] <Structure of Contact Detection Device 100>

[0046] The contact detection device 100 includes an electrostatic sensor 110 and a HODECU (Hands Off Detection Electronic Control Unit) 120.

[0047] The electrostatic sensor 110 is disposed around the circumference of the grip 11 of the steering wheel 10, and is made of, for example, metal electrodes. The electrostatic sensor 110 is connected to the HODECU 120 via signal line 12.

[0048] HODECU120 is located inside the steering wheel 10 as an example. Figure 1 The HODECU120 is shown in enlarged form. The HODECU120 has an AFE (Analog Front End) 120A and an MPU (Micro Processor Unit) 120B.

[0049] AFE120A is connected to electrostatic sensor 110. Based on instructions received from MPU120B, it inputs a sine wave (input sine wave) to electrostatic sensor 110 and obtains a sine wave (output sine wave) output from electrostatic sensor 110. AFE120A obtains the capacitance value of electrostatic sensor 110 from the input and output sine waves, performs low-pass filter-based noise removal along with digital conversion, and outputs it to MPU120B as an AD value. The AD value is an example of a detected value. The AD value is characterized by a dimensionless count value. By performing low-pass filter-based noise removal by AFE120A, contact determination device 100 can obtain an AD value with noise above a given frequency removed.

[0050] The MPU120B is implemented as a computer including a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), input / output interfaces, and an internal bus. As an example, the MPU120B is connected to an ECU 50. The ECU 50 is a control device that controls the electronic equipment of the vehicle equipped with the steering wheel 10. This electronic equipment may be, for example, related to the vehicle's autonomous driving capabilities.

[0051] The MPU120B includes a main control unit 121, a correction unit 122, a contact determination unit 123, and a memory 124. The main control unit 121, the correction unit 122, and the contact determination unit 123 represent the functions (responsibilities) of the program executed by the MPU120B as function blocks. In addition, the memory 124 functionally represents the memory of the MPU120B.

[0052] The main control unit 121 is a processing unit that oversees the control processing of the MPU120B and performs processing other than that performed by the correction unit 122 and the contact determination unit 123.

[0053] The correction unit 122 corrects the reference value used by the contact determination unit 123 for determination. The reference value is the capacitance value of the electrostatic sensor 110 used by the contact determination unit 123 when determining whether the hand H is in contact with the grip 11 of the steering wheel 10. For example, when the hand H contacts the grip 11, the capacitance value of the electrostatic sensor 110 changes according to subtle changes in the distance between the hand H and the electrostatic sensor 110, temperature changes, etc. To eliminate the amount of variation in the capacitance value of the electrostatic sensor 110 caused by such variations, and to detect the amount of variation in the capacitance value caused by whether or not the hand H is in contact, the reference value of the capacitance value of the electrostatic sensor 110 is used. The correction unit 122 corrects the detected value according to subtle changes in distance, temperature, etc. Figures 4 to 7 The correction method based on the detection value of the correction unit 122 will be described later. The correction unit 122 has the function of performing... Figure 6 as well as Figure 7 The timer is used during processing.

[0054] The contact determination unit 123 determines whether the hand H is in contact with the handle 11 by judging whether the difference obtained by subtracting a reference value from the capacitance value of the electrostatic sensor 110 exceeds a threshold. The contact determination unit 123 notifies the ECU 50 of the data characterizing the determination result.

[0055] The memory 124 stores programs and data required for processing by the main control unit 121, the correction unit 122, and the contact determination unit 123. The memory 124 stores data characterizing the capacitance value of the electrostatic sensor 110, data generated by the correction unit 122 and the contact determination unit 123 during processing, etc.

[0056] <Output sine wave of electrostatic sensor 110>

[0057] Figure 2 This is a diagram showing an example of the output sine wave of the electrostatic sensor 110. Figure 2 The output sine wave is shown in solid line when the hand H leaves the handle 11 (when released), and the output sine wave is shown in dashed line when the hand H grasps the handle 11 (when touched).

[0058] Since the capacitance of the electrostatic sensor 110 changes when the hand H touches the handle 11 compared to when it is released, the phase and amplitude of the sine wave during touch change compared to the sine wave when released. The phase and amplitude of the sine wave during touch vary depending on the degree of contact between the hand H and the handle 11. The degree of contact refers to, for example, whether the hand H lightly grips the handle 11, or grips it firmly, or whether the area of ​​contact between the hand H and the handle 11 is small, or large, etc.

[0059] For example, the timing when the amplitude becomes zero upon release is predetermined as the detection timing td. If the amplitude of the sine wave is detected at the detection timing td, the AD value corresponding to the degree of contact between the hand and H can be obtained. This is because the change in amplitude at the detection timing td is equivalent to the AD value.

[0060] <Contact determination using reference values>

[0061] Figure 3 This diagram illustrates the contact determination using reference values. Figure 3 In the diagram, the horizontal axis represents time, and the vertical axis represents voltage. Figure 3 The AD value is represented by a solid line, the reference value by a dashed line, and the difference between the AD value and the reference value (AD value - reference value) is shown by a dotted-dash line.

[0062] Before time t1, it is assumed that hand H is not in contact with handle 11. If hand H contacts handle 11 at time t1, the AD value will increase relative to the reference value. At this time, the difference (AD value - reference value) also increases, exceeding the contact threshold Th1, and thus the contact determination unit 123 determines that hand H has contacted handle 11. Furthermore, if hand H leaves handle 11 at time t2, the AD value will decrease. At this time, the difference (AD value - reference value) also decreases, becoming below the departure threshold Th2, which is lower than the contact threshold Th1, and thus the contact determination unit 123 determines that hand H has left handle 11.

[0063] <Correction based on the reference value of correction unit 122>

[0064] The correction unit 122 changes the calculation method of the reference value when the touch is released and when the touch is made. Here, as an example, it is assumed that the HODECU 120 performs control processing every 10 ms (milliseconds).

[0065] When the correction unit 122 is released, it uses the following formula (1) to calculate the reference value. M represents the weight in the weighted average. The reference value (10ms ago) is the reference value calculated by the correction unit 122 10ms ago. The correction unit 122 calculates the weighted average of the reference value (10ms ago) and the AD value by multiplying the reference value (10ms ago) by the weight M based on formula (1). Formula (1) is a formula that uses a weighted average relative to the reference value (10ms ago) to reflect the latest AD value. The larger the value of M, the less susceptible the reference value calculated by formula (1) is to be affected by the AD value, and the smaller the value of M, the more susceptible the reference value calculated by formula (1) is to be affected by the AD value. The value of the weight M can be set to an appropriate value corresponding to the characteristics, sensitivity, etc. of the electrostatic sensor 110.

[0066]

Mathematical Formula 1

[0067]

[0068] Furthermore, the correction unit 122 calculates the reference value using the following equation (2) upon touch. M represents the weight in the weighted average. The weight M can be the same as the weight M in equation (1) or it can be a different value. The correction unit 122 calculates the weighted average of the reference value (10ms ago) and the cumulative maximum value by multiplying the reference value (10ms ago) by the weight M based on equation (2).

[0069] In other words, the correction unit 122 corrects the reference value based on the cumulative maximum value.

[0070]

Mathematical Formula 2

[0071]

[0072] Here, the so-called cumulative maximum value is the maximum value among cumulative values; more specifically, it is the maximum value when the direction of change of the AD value corresponding to the increase in the degree of contact (the direction of the increase in AD value) is set to positive. Furthermore, the cumulative value is the cumulative value obtained by accumulating the change in AD value ΔAD from the moment the hand H begins contacting the handle 11. When calculating (updating) the cumulative value, the correction unit 122 does not accumulate the change in AD value ΔAD without limit, but rather adds a value within a certain range to the previously calculated cumulative value. Figure 7 The details of this process will be described later.

[0073] Equation (2) is a formula that uses a weighted average relative to the reference value (10ms ago) to reflect the cumulative maximum value. The larger the value of M, the less the reference value calculated by Equation (2) is affected by the cumulative maximum value; the smaller the value of M, the more easily the reference value calculated by Equation (2) is affected by the cumulative maximum value. The value of weight M can be set to an appropriate value corresponding to the characteristics, sensitivity, etc. of the electrostatic sensor 110. In addition, as mentioned above, the weight M in Equation (2) can be the same as the weight M in Equation (1), or it can be a different value.

[0074] The correction unit 122 corrects the reference value using equation (1) when the hand is released and uses equation (2) when the hand is touched. Since the capacitance value of the electrostatic sensor 110 changes according to the subtle distance between the hand H and the electrostatic sensor 110, temperature changes, etc. when the hand is touched, the correction unit 122 uses the cumulative maximum value to obtain the reference value according to equation (2) so as not to make misjudgments.

[0075] <Contact determination process performed by contact determination unit 123>

[0076] Figures 4 to 7 This is a flowchart representing the contact determination process performed by the MPU120B.

[0077] If the contact determination unit 123 is connected to the power supply, it will start processing and set the initialization flag to TRUE (step S1).

[0078] The contact determination unit 123 sets the reference value to MAX (step S2).

[0079] The contact determination unit 123 sets the contact state to release (state = release) (step S3).

[0080] The contact determination unit 123 obtains the AD value from AFE120A (step S4).

[0081] The contact determination unit 123 determines whether the difference between the AD value and the reference value (AD value - reference value) is greater than the threshold Th (step S5). In step S5, the contact determination unit 123 uses the contact threshold Th1 (refer to) when the contact state is released. Figure 3 ) as Th. Furthermore, in step S5, the contact determination unit 123 uses the departure threshold Th2 (refer to) when the contact state is Touch. Figure 3 ) as Th.

[0082] If the contact determination unit 123 determines that the difference (AD value - reference value) is not greater than the threshold (S5: No), it determines that the contact state is released (State = Release) (step S6).

[0083] The contact determination unit 123 sets the initialization flag to TRUE (step S7).

[0084] The contact determination unit 123 performs a process that causes the correction unit 122 to correct the reference value of the released state (step S8). The correction process performed by the correction unit 122 to correct the reference value is a process of updating the reference value. Figure 5 The details of step S8 will be described later.

[0085] If the contact determination unit 123 finishes the process in step S8, it determines whether to end the series of processes (step S9). Ending the series of processes is, for example, when the power supply is set to off.

[0086] If the contact determination unit 123 determines that the series of processes should not be terminated (processing should continue) (S9: No), the process returns to step S4. This is to repeat the process in order to obtain the AD value. Alternatively, if the contact determination unit 123 determines that the series of processes should be terminated (S9: Yes), the series of processes is terminated (end).

[0087] If the contact determination unit 123 determines in step S5 that the difference (AD value - reference value) is greater than the threshold Th (S5: Yes), it determines that the contact state is touch (State = Touch) (step S10).

[0088] The contact determination unit 123 determines whether the initialization flag is TRUE (step S11).

[0089] If the contact determination unit 123 determines that the initialization flag is TRUE (S11: Yes), it sets the initialization flag to FALSE (step S12).

[0090] The touch determination unit 123 causes the correction unit 122 to perform a process to initialize the touch state (step S13). Using Figure 6 The details of step S13 will be described later.

[0091] The touch determination unit 123 causes the correction unit 122 to perform a process of correcting the reference value of the touch state (step S14). The correction process of the correction unit 122 on the reference value is a process of updating the reference value. Figure 7 The details of step S14 will be described later. If the contact determination unit 123 terminates the processing of step S14, the process proceeds to step S9.

[0092] The correction unit 122 performs correction processing on the reference value of the released state. Figure 5 )>

[0093] Correction Section 122 If it begins Figure 5 The process of correcting the reference value in the released state, as shown, involves correcting the reference value in the released state according to equation (1) (step S8A). The correction unit 122 calculates the weighted average of the reference value (10ms ago) and the AD value by multiplying the reference value (10ms ago) by the weight M based on equation (1). The correction unit 122 updates the reference value in the released state in this way. After the above, the process of correcting the reference value in the released state by the correction unit 122 ends (end).

[0094] The correction section 122 performs initialization processing on the touch state. Figure 6 )>

[0095] Correction section 122 only Figure 6 When the initialization flag shown is FALSE, the touch state initialization process is executed.

[0096] Correction Section 122 If it begins Figure 6 The process shown for initializing the touch state involves setting the timer to 0 seconds (step S13A).

[0097] The correction unit 122 sets the cumulative value to the reference value 10ms ago (10ms ago) and sets the cumulative maximum value to the reference value 10ms ago (10ms ago) (step S13B).

[0098] The correction unit 122 sets the AD value from 1 second ago (1 second ago) to the current AD value (step S13C). The correction unit 122 performs the process in step S13C to utilize this process when correcting (updating) the reference value of the touch state 1 second later. With this, the process of initializing the touch state by the correction unit 122 ends.

[0099] The correction unit 122 performs correction processing on the reference value of the touch state. Figure 7 )>

[0100] Correction Section 122 If it begins Figure 7 The process shown corrects the reference value for the touch state to determine whether the timer has exceeded 1 second (step S20). This is to update the accumulated value every 1 second.

[0101] If the correction unit 122 determines that the timer has not reached 1 second (S20: No), it adds 0.01 seconds (10ms) to the timer (step S21). This is because processing is performed every 0.01 seconds.

[0102] The correction unit 122 calculates the reference value at the time of touch using equation (2) (step S22). The correction unit 122 calculates the weighted average of the reference value (10ms ago) and the cumulative maximum value by multiplying the reference value (10ms ago) by a weight M based on equation (2). That is, the correction unit 122 adds a correction value based on the cumulative maximum value to the reference value at the start of contact between the hand H and the grip 11 of the steering wheel 10. Therefore, the contact determination device 100 can improve the correction accuracy of the reference value.

[0103] If the correction unit 122 determines in step S20 that the timer has lasted for more than 1 second (S20: Yes), it determines that the change in the AD value obtained by subtracting the AD value from 1 second ago (1 second ago) from the current AD value is greater than -K and less than K (step S23A). This is so that the change in the AD value is not accumulated indefinitely, but rather limited to a value within a certain range and added to the previously calculated cumulative value. The value within a certain range is an example of a value within a given range, defined by -K and K. Although the value of K can be set to a value between 2 and 5 as an example, it can also be set to an appropriate value corresponding to the characteristics, sensitivity, etc. of the electrostatic sensor 110.

[0104] Furthermore, since the correction unit 122 processes every 0.01 seconds, the condition determined in step S20 is when the timer's counting time reaches 1 second.

[0105] If the correction unit 122 determines that the change in the AD value is greater than -K and less than K (S23A: Yes), it sets the change in the AD value ΔAD to the change obtained by subtracting the AD value from 1 second ago (1 second ago) from the current AD value (step S24A). If the correction unit 122 finishes processing in step S24A, it proceeds to step S25. Here, the change in the AD value is the change (difference) obtained by subtracting the AD value from 1 second ago (1 second ago) from the current AD value, and it is the value used in the calculation of the cumulative value.

[0106] If the correction unit 122 determines in step S23A that the change in the AD value is not greater than -K, or not less than K (S23A: No), then it determines whether the change in the AD value is less than -K (step S23B).

[0107] If the correction unit 122 determines that the change in the AD value is -K or less (S23B: Yes), it sets the change in the AD value ΔAD to -K (step S24B). In this case, the change in the AD value ΔAD is set to the lower limit value -K, which is used to limit the value to a certain range. If the correction unit 122 ends the processing in step S24B, it proceeds to step S25.

[0108] Furthermore, if the correction unit 122 determines in step S23B that the change in the AD value is not below -K (S23B: No), it sets the change in the AD value ΔAD to K (step S24C). In this case, since the change in the AD value is above K, the change in the AD value ΔAD is set to the upper limit value K used to limit it to a certain range. If the correction unit 122 ends the processing in step S24C, it proceeds to step S25.

[0109] The correction unit 122 updates the cumulative value by adding the change in AD value ΔAD to the cumulative value at the current time point (step S25). That is, the cumulative value (updated value) = the cumulative value (the value at the current time point before the update) + ΔAD.

[0110] The correction unit 122 determines whether the cumulative maximum value at the current time point is smaller than the cumulative value updated in step S25 (step S26). This is to determine whether to update the cumulative maximum value.

[0111] If the correction unit 122 determines that the cumulative maximum value at the current time point is smaller than the cumulative value updated in step S25 (S26: Yes), it updates the cumulative maximum value to the cumulative value updated in step S25 (step S27). That is, the cumulative maximum value = the cumulative value.

[0112] Correction unit 122 resets the timer to 0 seconds (step S28). This is to count the next second.

[0113] The correction unit 122 sets the AD value from 1 second ago (1ms ago) to the current AD value (step S29). That is, AD value (1ms ago) = AD value. This is to prepare for processing 1 second later, using the current AD value as the AD value 1 second later (1ms ago). If the correction unit 122 finishes processing in step S29, the process proceeds to step S22.

[0114] <Operation of the contact detection device 100>

[0115] Figures 8 to 10 This is a diagram illustrating the operation of the contact determination device 100. Figures 8 to 10 The middle horizontal axis represents time (seconds). Figure 8 The display shows the AD value, ΔAD, cumulative value, cumulative maximum value, reference value, AD value - reference value (i.e., the difference between the AD value and the reference value), threshold, and contact state. The AD value, ΔAD, cumulative value, cumulative maximum value, reference value, AD value - reference value, and threshold are characterized by the count value of electrostatic capacitance. The AD value is a measured value. The contact state characterizes the determination result of the contact determination device 100 for either a release state or a touch state.

[0116] Figure 9Displays the AD value, ΔAD, cumulative value, and cumulative maximum value. Figure 10 Displays the cumulative maximum value, baseline value, AD value - baseline value, threshold, and contact status.

[0117] Here, the actual movement of hand H is as follows: initially, it is in a released state without contacting the handle 11; then it contacts the handle 11 and becomes a touching state; finally, it slowly removes hand H from the handle 11 and returns to a released state. This actual contact state is shown below the horizontal axis. It will be explained whether the actual contact state shown below the horizontal axis is consistent with the contact determination result of the contact determination device 100.

[0118] Figure 8 As shown, after approximately 4 seconds, if the AD value minus the reference value exceeds the threshold, the contact determination device 100 switches its contact determination from the released state to the touch state, and a cumulative value appears. The cumulative value changes slowly from the AD value upwards. If the cumulative value increases, the maximum cumulative value is updated approximately every 6 seconds and then every 12 seconds, gradually increasing. The reference value changes slowly, as if influenced by the maximum cumulative value, but without significant fluctuations, remaining relatively stable.

[0119] Even if the AD value fluctuates significantly during the touch state, the AD value-reference value changes accordingly because the reference value is relatively stable. Even if, starting from approximately 14 seconds into the touch state, the hand H is slowly removed from the grip 11, causing the AD value to decrease, the AD value-reference value decreases steadily because the reference value remains stable. Approximately 22 seconds after the actual contact state transitions to the release state, the contact determination device 100 reverts to the release state determination. These determinations are consistent with the actual contact state shown below the horizontal axis.

[0120] Furthermore, if the temperature of the electrostatic sensor 110 rises during the contact state determination process described above, it can be confirmed that both the AD value and the reference value have increased. Therefore, when the temperature of the electrostatic sensor 110 rises during the contact state determination process, the contact determination device 100 can also compensate for the reference value corresponding to the temperature change, thereby suppressing false determinations and accurately determining the touch state.

[0121] <Comparative example actions>

[0122] Figures 11 to 13 This diagram illustrates the operation of a comparative example contact determination device used for comparison with contact determination device 100. The comparative example contact determination device does not calculate a cumulative value, but instead calculates a reference value according to equation (1) even in the touch state, which is different from... Figures 8 to 10 The operation of the contact determination device 100 shown is different. Figures 11 to 13The middle horizontal axis represents time (seconds). Furthermore, in... Figures 11 to 13 In this context, the AD value and ΔAD are the same as the operation of the contact determination device 100, that is, they are the same as... Figures 8 to 10 The AD value and ΔAD are the same. Furthermore, in... Figures 11 to 13 In this example, the operation of the contact determination device 100 differs from that of the reference value (comparative example), AD value - reference value (comparative example), threshold (comparative example), and contact state (comparative example), demonstrating the operation of the contact determination device in the comparative example. Figure 11 The diagram shows the AD value, ΔAD, reference value (comparative example), AD value - reference value (comparative example), threshold (comparative example), and contact state (comparative example). The AD value, ΔAD, reference value (comparative example), AD value - reference value (comparative example), and threshold (comparative example) are characterized by the count value of electrostatic capacitance. Furthermore, the AD value is a measured value.

[0123] Figure 12 The AD value and ΔAD are shown. Figure 13 The following values ​​are shown: baseline value (comparison example), AD value - baseline value (comparison example), threshold (comparison example), and contact state (comparison example).

[0124] Here, the movement and use of hand H Figures 8 to 10 The movement of hand H is the same as described above, namely, initially in a released state without contact with handle 11, then in a touching state with contact with handle 11, and finally slowly removing hand H from handle 11 to return to a released state. This actual contact state is shown below the horizontal axis. It is explained whether the actual contact state shown below the horizontal axis is consistent with the contact determination of the contact state (comparative example) by the contact determination device of the comparative example.

[0125] like Figure 11 As shown, after about 4 seconds, if the AD value minus the reference value (comparison example) exceeds the threshold, the actual contact state switches from the release state to the touch state, and the contact determination device of the comparison example changes the contact determination of the contact state (comparison example) to the touch state.

[0126] If, starting from approximately 14 seconds into the touch state, the hand H is slowly removed from the grip 11, causing the AD value to decrease, the reference value (comparative example) will also decrease accordingly. However, starting from approximately 22 seconds into the actual contact state to the release state, the AD value minus the reference value (comparative example) begins to increase and exceed the threshold. Therefore, the contact determination device in the comparative example maintains the contact determination of the contact state (comparative example) as a touch state. This differs from the actual contact state, resulting in a false determination.

[0127] As described above, if the contact detection device 100 determines that a touch state has been established, then... Figure 7In step S25, the change in the AD value ΔAD is added to the cumulative value at the current time point to update the cumulative value. Furthermore, in Figure 7 In step S22, the weighted average of the baseline value (10ms ago) and the cumulative maximum value is obtained by multiplying the baseline value (10ms ago) by the weight M using equation (2). That is, the baseline value is corrected based on the cumulative maximum value.

[0128] Therefore, even if the gripping method, grip position, or contact method of the hand H when gripping the handle 11 changes during the touch state, the reference value, which is corrected based on the maximum cumulative value (the maximum of the cumulative values), will not follow the AD value but will remain stable. This also applies to temperature increases in the electrostatic sensor 110. As a result, even if the gripping method, position, or contact method of the handle 11 changes, or the temperature increases, the change from a touch state to a release state can be stably determined by comparing the difference between the AD value and the reference value (AD value - reference value) with a threshold. This is as follows... Figures 8 to 10 As shown.

[0129] Therefore, a contact determination device 100 can be provided that can correct for a reference value corresponding to temperature changes during the contact period, and can also detect when the hand H is slowly removed from the handle 11.

[0130] Furthermore, since the correction unit 122 corrects the reference value when the cumulative maximum value in the cumulative value is updated, the contact determination device 100 can detect the object leaving the contact while using the reference value based on the latest cumulative maximum value to correct the reference value corresponding to the temperature change during the contact.

[0131] Furthermore, since the correction unit 122 adds the change in AD value ΔAD to the cumulative value within a given range when accumulating the change in AD value ΔAD and updating the cumulative value, the contact determination device 100 can suppress the influence of the rapid change when the AD value (measured value) changes drastically over time due to noise or the like, thereby improving the correction accuracy of the reference value.

[0132] Furthermore, the correction unit 122 can replace the previous method of adding the AD value variation ΔAD to the accumulated value only when the AD value variation ΔAD is within a given range, instead of adding it to the accumulated value only when the AD value variation ΔAD is within the given range. When the accumulated value is obtained in this way, the contact determination device 100 can suppress the effects of rapid changes even if the AD value (measured value) changes drastically over time due to noise, etc., thereby improving the correction accuracy of the reference value.

[0133] Furthermore, the correction unit 122 updates the accumulated value for each given period. This given period is an example of the first given period. The given period used for updating the accumulated value can be set to an appropriate value corresponding to the characteristics, sensitivity, etc. of the electrostatic sensor 110, or the environment of the contact determination device 100. As a result, the contact determination device 100 can improve the correction accuracy of the reference value.

[0134] Furthermore, the change in AD value ΔAD is the change in AD value relative to 1 second ago (an example of a given period). This given period is an example of a second given period. The period before the given period is not limited to 1 second ago, and can be set to an appropriate value corresponding to the characteristics, sensitivity, etc. of the electrostatic sensor 110, or the environment of the contact determination device 100. As a result, the contact determination device 100 can improve the correction accuracy of the reference value.

[0135] Furthermore, if the latest cumulative value is greater than the maximum cumulative value, the correction unit 122 updates the maximum cumulative value to the latest cumulative value and corrects the reference value based on the updated maximum cumulative value. On the other hand, if the maximum cumulative value is greater than or equal to the latest cumulative value, the correction unit 122 corrects the reference value based on the maximum cumulative value. Thus, the contact determination device 100 can always correct the reference value based on the maximum cumulative value, which is the largest cumulative value, and can stably determine the contact state.

[0136] Furthermore, the correction unit 122 can perform correction instead of the aforementioned method of updating the cumulative maximum value, as follows: if the difference between the cumulative maximum value and the latest cumulative value is less than or equal to a given value, the reference value is corrected based on the latest cumulative value; if the difference is greater than the given value, the reference value is corrected based on the difference between the cumulative maximum value and the given value. In this way, the contact determination device 100 can also improve the accuracy of the reference value correction.

[0137] Furthermore, since the correction unit 122 adds a correction value based on the cumulative maximum value to the reference value at the start of contact between the hand H and the grip 11 of the steering wheel 10, the contact determination device 100 is able to improve the correction accuracy of the reference value.

[0138] Furthermore, since the correction unit 122 corrects the reference value by taking a weighted average of the reference value and the cumulative maximum value, the contact determination device 100 can correct the reference value while balancing the reference value and the cumulative maximum value, thereby improving the correction accuracy of the reference value.

[0139] Furthermore, the correction unit 122 can replace the weighted average and correct the reference value by calculating the moving average of the cumulative maximum values ​​of a given number of quantities in the past. The contact determination device 100 is not limited to the weighted average; it can also improve the correction accuracy of the reference value by correcting the reference value by using a moving average based on the cumulative maximum value.

[0140] Since the contact determination unit 123 determines whether the hand H is in contact with the grip 11 of the steering wheel 10 by determining whether the difference (AD value - reference value) obtained by subtracting the reference value from the AD value exceeds the threshold, the contact determination device 100 can determine the contact state (touch state or release state) in a stable manner corresponding to the threshold and suppressing false determinations.

[0141] Since an electrostatic sensor 110 is used as the sensor to measure the degree of contact between the hand H and the grip 11 of the steering wheel 10, the contact determination device 100 can improve the accuracy of measuring the degree of contact between the hand H and the grip 11.

[0142] Furthermore, since the AD value is obtained by removing noise above a given frequency from the output of the electrostatic sensor 110 using a low-pass filter with AFE120A, the contact determination device 100 can improve the accuracy of the measurement of the degree of contact of the hand H by removing noise.

[0143] Alternatively, a pressure sensor can be used instead of the electrostatic sensor 110. For example, a strain gauge type or an electrostatic capacitive pressure sensor can be used as the pressure sensor. Even when using a pressure sensor, the contact determination device 100 can improve the accuracy of measuring the degree of contact of the hand H.

[0144] Alternatively, an AD value can be used, which is the result of removing noise above a given frequency from the pressure sensor output using a low-pass filter with an AFE120A. The contact determination device 100 can improve the accuracy of measuring the degree of contact of hand H by removing noise.

[0145] Furthermore, this section explains how to correct the reference value based on the cumulative maximum value when the AD value increases in response to increased contact intensity. However, when the AD value decreases in response to increased contact intensity, the reference value can be corrected based solely on the cumulative minimum value (cumulative minimum). Figure 14 To illustrate this action.

[0146] Figure 14This is a diagram illustrating the operation of the contact determination device 100 in a modified embodiment. Figure 14 The middle horizontal axis represents time (seconds). Figure 14 The display shows the AD value, ΔAD, cumulative value, cumulative minimum value, reference value, AD value - reference value (i.e., the difference between the AD value and the reference value), threshold, and contact state. The AD value, ΔAD, cumulative value, cumulative minimum value, reference value, AD value - reference value, and threshold are characterized by the count value of electrostatic capacitance. The AD value is a measured value. The contact state characterizes the determination result of the contact determination device 100 for either a release state or a touch state.

[0147] Here, with use Figure 8 Similarly, the actual movement of the hand H is as follows: initially, it is in a released state without contact with the handle 11; then it contacts the handle 11 and becomes a touching state; finally, the hand H is slowly removed from the handle 11 and returns to a released state. This actual contact state is shown below the horizontal axis. It will be explained whether the actual contact state shown below the horizontal axis is consistent with the contact determination result of the contact determination device 100.

[0148] like Figure 14 As shown, if the AD value minus the reference value falls below the threshold after approximately 4 seconds, the contact determination device 100 switches its contact determination from the released state to the touch state, and a cumulative value appears. The cumulative value changes more slowly than the AD value. If the cumulative value increases, the cumulative minimum value is updated approximately every 6 seconds and gradually decreases. The reference value changes slowly, as if pulled by the cumulative minimum value, but without large fluctuations, remaining relatively stable.

[0149] Since the reference value remains relatively stable even when the AD value fluctuates significantly during the touch state, the AD value minus the reference value changes with the AD value. Even when the AD value begins to increase as the hand H is slowly removed from the grip 11 starting from approximately 15 seconds into the touch state, the reference value remains stable, resulting in a stable increase in the AD value minus the reference value. Approximately 20 seconds after the actual contact state transitions to the release state, the contact determination device 100 reverts to the release state in its determination of the contact state. These determinations are consistent with the actual contact state shown below the horizontal axis. Thus, a contact determination device 100 can be provided that, even when the AD value decreases as the degree of contact increases, it can compensate for the reference value corresponding to temperature changes during the touch state (contact period), and detect the removal of the hand H from the grip 11 even when the hand H is slowly removed.

[0150] Furthermore, the above has explained how the contact determination device 100 is used for determining HOD, but the application of the contact determination device 100 is not limited to determining HOD. As long as a part of a living organism such as a hand H touches an object equipped with an electrostatic sensor 110 for a relatively long period of time, the contact determination device 100 can also determine the contact state.

[0151] The above describes the contact determination device and contact determination method according to exemplary embodiments of the present invention. However, the present invention is not limited to the specific disclosed embodiments and can be modified and altered in various ways without departing from the claims.

Claims

1. A contact determination device, characterized in that, Include: The sensor measures the degree of contact between the detected object and the target object, and outputs a detection value corresponding to the degree of contact. The contact determination unit determines whether the detected object is in contact with the object based on a reference value used in determining whether the detected object is in contact with the object and the detection value; and The correction unit corrects the reference value. The correction unit performs the following processing: During the period when the contact determination unit determines that the detected object is in contact with the object, among the cumulative values ​​obtained by accumulating the changes in the detection values ​​from the start of contact between the detected object and the object, if the detection value increases in response to an increase in the degree of contact, the reference value is corrected based on the maximum value of the cumulative value; or, if the detection value decreases in response to an increase in the degree of contact, the reference value is corrected based on the minimum value of the cumulative value. When the detected value increases in response to an increase in the degree of contact, if the maximum value of the cumulative value is less than the latest cumulative value, the maximum value of the cumulative value is updated to the latest cumulative value, and the reference value is corrected based on the updated maximum value of the cumulative value. If the maximum value of the cumulative value is greater than or equal to the latest cumulative value, the reference value is corrected based on the updated maximum value. Alternatively, when the detected value decreases in response to an increase in the degree of contact, if the minimum value of the cumulative value is greater than the latest cumulative value, the minimum value of the cumulative value is updated to the latest cumulative value, and the reference value is corrected based on the updated minimum value of the cumulative value. If the minimum value of the cumulative value is less than or equal to the latest cumulative value, the reference value is corrected based on the minimum value of the cumulative value.

2. A contact determination device, characterized in that, Include: The sensor measures the degree of contact between the detected object and the target object, and outputs a detection value corresponding to the degree of contact. The contact determination unit determines whether the detected object is in contact with the object based on a reference value used in determining whether the detected object is in contact with the object and the detection value; and The correction unit corrects the reference value. The correction unit performs the following processing: During the period when the contact determination unit determines that the detected object is in contact with the object, among the cumulative values ​​obtained by accumulating the changes in the detection values ​​from the start of contact between the detected object and the object, if the detection value increases in response to an increase in the degree of contact, the reference value is corrected based on the maximum value of the cumulative value; or, if the detection value decreases in response to an increase in the degree of contact, the reference value is corrected based on the minimum value of the cumulative value. When the detected value increases in response to an increase in the degree of contact, if the absolute value of the difference between the maximum value of the cumulative value and the latest cumulative value is below a given value, the reference value is corrected based on the latest cumulative value; if the absolute value of the difference is greater than the given value, the reference value is corrected based on the difference between the maximum value of the cumulative value and the given value. Alternatively, when the detected value decreases in response to an increase in the degree of contact, if the absolute value of the difference between the minimum value of the cumulative value and the latest cumulative value is below a given value, the reference value is corrected based on the latest cumulative value; if the absolute value of the difference is greater than the given value, the reference value is corrected based on the difference between the minimum value of the cumulative value and the given value.

3. A contact determination device, characterized in that, Include: The sensor measures the degree of contact between the detected object and the target object, and outputs a detection value corresponding to the degree of contact. The contact determination unit determines whether the detected object is in contact with the object based on a reference value used in determining whether the detected object is in contact with the object and the detection value; and The correction unit corrects the reference value. The correction unit performs the following processing: During the period when the contact determination unit determines that the detected object is in contact with the object, among the cumulative values ​​obtained by accumulating the changes in the detection values ​​from the start of contact between the detected object and the object, if the detection value increases in response to an increase in the degree of contact, the reference value is corrected based on the maximum value of the cumulative value; or, if the detection value decreases in response to an increase in the degree of contact, the reference value is corrected based on the minimum value of the cumulative value. When the detected value increases in response to an increase in the degree of contact, the reference value is corrected by taking the moving average of the maximum value of the cumulative values ​​of a given number of quantities in the past; or, when the detected value decreases in response to an increase in the degree of contact, the reference value is corrected by taking the moving average of the minimum value of the cumulative values ​​of a given number of quantities in the past.

4. The contact determination device according to any one of claims 1 to 3, wherein, The correction unit performs the following processing: When the detected value increases in response to an increase in the degree of contact, the reference value is corrected when the maximum value in the cumulative value is updated; or, when the detected value decreases in response to an increase in the degree of contact, the reference value is corrected when the minimum value in the cumulative value is updated.

5. The contact determination device according to any one of claims 1 to 3, wherein, The correction unit performs the following processing: When updating the cumulative value by accumulating the changes in the detected values, the changes in the detected values ​​are limited to a value within a given range and added to the cumulative value.

6. The contact determination device according to any one of claims 1 to 3, wherein, The correction unit performs the following processing: When updating the cumulative value by accumulating the changes in the detected values, the changes in the detected values ​​are added to the cumulative value only if the changes in the detected values ​​are within a given range.

7. The contact determination device according to any one of claims 1 to 3, wherein, The correction unit updates the cumulative value for each given first period.

8. The contact determination device according to any one of claims 1 to 3, wherein, The change in the detected value is the change in the detected value relative to the period prior to the second given period.

9. The contact determination device according to any one of claims 1 to 3, wherein, The correction unit performs the following processing: If the detected value increases in response to an increase in the degree of contact, a correction value based on the maximum value of the cumulative value is added to the reference value at the start of contact between the detected object and the object; or, if the detected value decreases in response to an increase in the degree of contact, a correction value based on the minimum value of the cumulative value is added to the reference value at the start of contact between the detected object and the object.

10. The contact determination device according to any one of claims 1 to 3, wherein, The correction unit performs the following processing: When the detected value increases in response to an increase in the degree of contact, the reference value is corrected by taking the weighted average of the maximum value of the reference value and the cumulative value. Alternatively, when the detected value decreases in response to an increase in the degree of contact, the reference value is corrected by taking the weighted average of the minimum value of the reference value and the cumulative value.

11. The contact determination device according to any one of claims 1 to 3, wherein, The contact determination unit determines whether the detected object is in contact with the target object by determining whether the difference obtained by subtracting the reference value from the detected value exceeds a threshold.

12. The contact determination device according to any one of claims 1 to 3, wherein, The sensor is an electrostatic sensor.

13. The contact determination device according to any one of claims 1 to 3, wherein, The sensor is an electrostatic sensor, and the detected value is obtained by removing noise above a given frequency using a low-pass filter.

14. The contact determination device according to any one of claims 1 to 3, wherein, The sensor is a pressure sensor.

15. The contact determination device according to any one of claims 1 to 3, wherein, The sensor is a pressure sensor, and the detected value is obtained by removing noise above a given frequency using a low-pass filter.

16. A contact determination method, characterized in that, It includes the following steps: Sensors are used to determine the degree of contact between the tested object and the object, and a detection value corresponding to the degree of contact is output. The determination of whether the detected object is in contact with the object is based on the reference value used in determining whether the detected object is in contact with the object and the detection value. as well as The reference value is corrected. In the correction step, during the period when it is determined by the determination step that the detected object is in contact with the object, the reference value is corrected based on the maximum value of the cumulative value obtained by accumulating the change in the detection value from the start of the contact between the detected object and the object, if the detection value increases in response to an increase in the degree of contact; or, if the detection value decreases in response to an increase in the degree of contact, the reference value is corrected based on the minimum value of the cumulative value. When the detected value increases in response to an increase in the degree of contact, if the maximum value of the cumulative value is less than the latest cumulative value, the maximum value of the cumulative value is updated to the latest cumulative value, and the reference value is corrected based on the updated maximum value of the cumulative value. If the maximum value of the cumulative value is greater than or equal to the latest cumulative value, the reference value is corrected based on the updated maximum value. Alternatively, when the detected value decreases in response to an increase in the degree of contact, if the minimum value of the cumulative value is greater than the latest cumulative value, the minimum value of the cumulative value is updated to the latest cumulative value, and the reference value is corrected based on the updated minimum value of the cumulative value. If the minimum value of the cumulative value is less than or equal to the latest cumulative value, the reference value is corrected based on the minimum value of the cumulative value.

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