Apparatus and method for steering wheel touch detection

Abstract

The present disclosure provides an apparatus and method for steering wheel touch detection, wherein the steering wheel comprises a plurality of touch detection sensors, the method comprising: generating a plurality of reference signals corresponding to a plurality of preselected frequencies, the number of the plurality of touch detection sensors being the same as the number of the plurality of reference signals; for each of the plurality of reference signals, applying it to each of the plurality of touch detection sensors non-overlapping in time, each touch detection sensor modulating the reference signal applied thereto to produce a corresponding modulated signal; and detecting and demodulating the modulated signal produced by each touch detection sensor to obtain a touch detection signal of each touch detection sensor under the reference signal; and determining a touch detection state of the steering wheel based on the touch detection signal of each touch detection sensor under each of the plurality of reference signals.

Description

TECHNICAL FIELD

[0001] The present application relates to steering wheel touch detection, and more particularly, to an apparatus and method for steering wheel touch detection. BACKGROUND

[0002] Currently, the automatic driving technology is not mature, and the assisted driving technology such as the Advanced Driving Assistance System (ADAS) only allows the vehicle to be in an automatic driving state for a short time, therefore, for the purpose of safety, more and more vehicle manufacturers configure the Hands off Detection (HOD) function for the vehicle. For example, by integrating a capacitive sensor in the steering wheel to detect whether the driver's hands are away from the steering wheel. However, the HOD function currently configured by the vehicle uses a single frequency reference signal, when the frequency is disturbed (for example, EMC (Electro Magnetic Compatibility)), the resulting sensing result is inaccurate, thereby causing the HOD function to fail to achieve the desired effect. SUMMARY

[0003] In view of this, the present disclosure provides a method and apparatus for steering wheel touch detection, which uses the principle of time-sharing frequency hopping, uses multiple reference signals with different frequencies to implement hands off detection for the vehicle, and avoids inaccurate detection results or inability to detect due to disturbance of a single frequency signal.

[0004] According to an aspect of the present application, a method for steering wheel touch detection is provided, wherein the steering wheel comprises a plurality of touch detection sensors. The method comprises: generating a plurality of reference signals corresponding to a plurality of preselected frequencies one by one, wherein the number of the plurality of touch detection sensors is the same as the number of the plurality of reference signals; for each reference signal in the plurality of reference signals, applying it to each touch detection sensor in the plurality of touch detection sensors without overlapping in time, wherein each touch detection sensor modulates the reference signal applied to it to generate a corresponding modulated signal; and detecting the modulated signal generated by each touch detection sensor in the plurality of touch detection sensors and demodulating the modulated signal to obtain the touch detection signal of each touch detection sensor in the plurality of touch detection sensors under the reference signal; and determining the touch detection state of the steering wheel based on the touch detection signal of each touch detection sensor in the plurality of touch detection sensors under each reference signal in the plurality of reference signals.

[0005] According to another aspect of the present application, there is provided an apparatus for steering wheel touch detection, the steering wheel comprising a plurality of touch detection sensors. The apparatus comprises: a signal generator configured to generate a plurality of reference signals corresponding to a plurality of preselected frequencies, and for each of the plurality of reference signals, to apply it to a respective one of the plurality of touch detection sensors non-overlapping in time, wherein each touch detection sensor modulates the reference signal applied thereto to produce a corresponding modulated signal, wherein the number of the plurality of touch detection sensors is the same as the number of the plurality of reference signals; a signal detector configured to detect the modulated signal produced by a respective one of the plurality of touch detection sensors and to demodulate the modulated signal to obtain a touch detection signal of the respective one of the plurality of touch detection sensors under the reference signal; and a signal processor configured to determine a touch detection state of the steering wheel based on the touch detection signal of the respective one of the plurality of touch detection sensors under each of the plurality of reference signals. BRIEF DESCRIPTION OF DRAWINGS

[0006] In order to more clearly illustrate the technical solutions of the embodiments of the present disclosure, the following will briefly introduce the drawings needed to be used in the description of the embodiments. Obviously, the drawings in the following description are only some of the example embodiments of the present disclosure, and other drawings can also be obtained by those of ordinary skill in the art without any creative effort on the basis of these drawings.

[0007] Figure 1 A steering wheel according to an embodiment of the present disclosure is schematically shown;

[0008] Figure 2 A steering wheel touch detection apparatus according to an embodiment of the present disclosure is schematically shown;

[0009] Figure 3 A structure of a signal generator in Figure 2 is schematically shown;

[0010] Figure 4A A way in which the signal generator in Figure 2 applies a reference signal to a respective one of the touch detection sensors in the steering wheel is schematically shown;

[0011] Figure 4B Another way in which the signal generator in Figure 2 applies a reference signal to a respective one of the touch detection sensors in the steering wheel is schematically shown;

[0012] Figure 5 A structure of a signal detector in Figure 2 is schematically shown;

[0013] Figure 6schematically illustrates Figure 2 the process of determining the touch detection state of the steering wheel based on the touch detection signals of each touch detection sensor under each reference signal in the plurality of reference signals;

[0014] Figure 7 schematically illustrates a steering wheel touch detection method according to an embodiment of the present disclosure;

[0015] Figure 8 schematically illustrates Figure 7 the flowchart of step 740 in

[0016] Figure 9 schematically illustrates a steering wheel touch detection method according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0017] The present application will be described in detail below with reference to exemplary embodiments of the present application. However, the present application is not limited to the embodiments described herein, which can be implemented in many different forms. The described embodiments are merely for making the present disclosure thorough and complete, and for fully conveying the concept of the present application to those skilled in the art. The features of each described embodiment can be combined or replaced with each other, unless explicitly excluded or should be excluded according to the context.

[0018] Figure 1 schematically illustrates a steering wheel according to an embodiment of the present disclosure.

[0019] Reference Figure 1 The steering wheel 100 is a steering wheel of any vehicle (especially a car), and during the driving of the vehicle, the driver can leave both hands off the steering wheel 100 due to the use of advanced driver assistance system (ADAS) or other reasons (such as dozing off, drunk, etc.), at which time the steering wheel 100 is in a hand-off (HO) state.

[0020] In order to detect whether the steering wheel 100 is in a hand-off state, the steering wheel 100 is divided into at least one touch detection zone, and at least one touch detection sensor is arranged in each touch detection zone. For example Figure 1 The steering wheel 100 is divided into three touch detection zones, i.e., a touch detection zone Z1 covering the front of the steering wheel, a touch detection zone Z2 covering the left back of the steering wheel, and a touch detection zone Z3 covering the right back of the steering wheel, as shown in Figure 1The number of touch detection zones in the steering wheel 100 and the number of touch detection sensors in each touch detection zone shown are merely examples, and the steering wheel 100 can be divided into any number of touch detection zones, and a plurality of touch detection sensors can also be redundantly arranged in each touch detection zone to detect the capacitance and / or resistance formed when the driver touches the corresponding touch detection zone in parallel to improve detection reliability.

[0021] It should be noted that, Figure 1 The number of touch detection zones in the steering wheel 100 and the number of touch detection sensors in each touch detection zone shown are merely examples, and the steering wheel 100 can be divided into any number of touch detection zones, and a plurality of touch detection sensors can also be redundantly arranged in each touch detection zone to detect the capacitance and / or resistance formed when the driver touches the corresponding touch detection zone in parallel to improve detection reliability.

[0022] For ease of understanding, the following describes the steering wheel touch detection device 200 according to the embodiment of the present disclosure with the example of the steering wheel 100 shown in FIG. 1. Figure 1 The three touch detection zones Z1, Z2, Z3 and the one touch detection sensor S1, S2, S3 arranged in each touch detection zone shown are merely examples.

[0023] Figure 2 The structure of the steering wheel touch detection device 200 according to the embodiment of the present disclosure is schematically shown.

[0024] The steering wheel touch detection device 200 can be located outside the steering wheel 100 or inside the steering wheel 100. As shown in FIG. 2, the steering wheel touch detection device 200 can be located inside the steering wheel 100. Figure 2 As shown in FIG. 2, the steering wheel touch detection device 200 includes a signal generator 210, a signal detector 220, and a signal processor 230.

[0025] The signal generator 210 can use a dedicated signal generator chip or a set of registers. For example, using a dedicated signal generator chip can generate reference signals of a predetermined frequency range, for example, can generate sine waves, square waves, and square waves with a frequency range of 0.1 Hz-20 MHz, can generate low-loss sine waves, triangular waves, and square waves from 0.001 HZ-300 kHz, or can generate sine waves, triangular waves, etc. with a frequency as high as 37.5 MHz. For example, in the case of using registers to generate reference signals, the output waveform and frequency can be controlled by software.

[0026] The signal generator 210 generates a plurality of reference signals equal to the number of touch detection sensors in time, i.e., at different times, which is for Figure 1In the case where one touch detection sensor is arranged in each of the touch detection zones shown, when each touch detection zone contains multiple touch detection sensors, for each touch detection zone, a plurality of reference signals equal to the number of touch detection sensors in the touch detection zone are generated, which respectively correspond to a plurality of preselected frequencies one by one. For example, reference signals W1, W2, W3 with frequencies of preselected frequencies F1, F2, F3 respectively are generated, and the waveforms thereof include but are not limited to sine waves, square waves, triangular waves, etc. For each reference signal W1, W2, W3, the signal generator 210 applies it to three touch detection sensors S1, S2, S3 in the touch detection zones Z1, Z2, Z3 without overlapping in time. The manner of applying the reference signals W1, W2, W3 includes but is not limited to the two manners shown in FIG. 4.

[0027] Each touch detection sensor S1, S2, S3 modulates the reference signal W1, W2, W3 applied thereto to generate a corresponding modulation signal M SiWj , where i is an integer between 1 and the number of touch detection sensors, and j is an integer between 1 and the number of preselected frequencies / reference signals. For each touch detection sensor S1, S2, S3, once a capacitance or resistance formed due to the driver touching the corresponding touch detection zone Z1, Z2, Z3 is sensed, a touch sensing signal is generated, at which time the modulation signal M SiWj (i = 1-3, j = 1-3) is equivalent to the superposition of the reference signals W1, W2, W3 and the touch detection signal. Conversely, for each touch detection sensor S1, S2, S3, if no capacitance or resistance formed due to the driver touching the touch detection zone Z1, Z2, Z3 is sensed, the modulation signal M SiWj does not contain the touch sensing signal.

[0028] The modulation signal M SiWj is detected by the signal detector 220 (for example, via a wireless or wired communication line), and the signal detector 220 can demodulate the modulation signal M SiWj to obtain the touch detection signal generated by each touch detection sensor S1, S2, S3 under each reference signal W1, W2, W3. If the touch detection sensor senses a capacitance and / or resistance formed due to the driver touching the corresponding touch detection zone, the modulation signal M SiWj demodulated will include the capacitance and / or resistance.

[0029] The modulation signal M SiWjThe demodulated touch detection signal will be processed by the signal processor 230. The signal processor 230 determines the touch detection state of the corresponding touch detection sensor based on the capacitance and / or resistance indicated by the touch detection signal, and further determines the touch detection state of the steering wheel 100. The touch detection state at least includes the hand-off state HO or the non-hand-off state Non-HO.

[0030] In addition, the steering wheel touch detection device 200 can further include a wireless communication module (not shown in the figure) for supporting the signal generator 210 to send the reference signal to each touch detection sensor and supporting the signal detector 220 to receive the modulated signal from each touch detection sensor.

[0031] It should be noted that, although Figure 2 The signal generator 210, the signal detector 220 and the signal processor 230 are shown as components inside the steering wheel touch detection device 200 in the above description, one or more of them can also be external devices with equivalent functions. For example, the signal processor 230 can be an external device such as a micro control unit MCU, a system on chip or a central processing unit CPU with computing and processing functions, which is communicatively connected to the signal generator 210 and the signal detector 220 through a data interface of the steering wheel touch detection device 200.

[0032] Figure 3 The structure of the signal generator 210 in the steering wheel touch detection device 200 is schematically shown in Figure 2

[0033] Referring to Figure 3 , the signal generator 210 includes a frequency selection unit 211, a signal generation unit 212 and a sensor selection unit 213. The frequency selection unit 211 is configured to select a plurality of preselected frequencies from a certain frequency range, such as the aforementioned F1, F2, F3. The signal generation unit 212 is configured to sequentially generate a plurality of reference signals corresponding to the plurality of preselected frequencies one by one, such as the aforementioned reference signals W1, W2, W3. The sensor selection unit 213 is configured to sequentially select each touch detection sensor to which the reference signal is to be applied, such as the aforementioned touch detection sensors S1, S2, S3.

[0034] Figure 4A A way for the signal generator in the steering wheel touch detection device 200 to apply the reference signal to each touch detection sensor in the steering wheel is schematically shown in Figure 2

[0035] The time for the steering wheel touch detection device 100 to complete one touch detection of the steering wheel is set as one detection period (for example, about 10 ms), and in each detection period, the signal generator 210 completes one application of each reference signal to each touch detection sensor in the touch detection area without time overlap. ​​

[0036] Referring to Figure 4A Each of the touch detection sensors is sequentially selected by the frequency selection unit 211 in the signal generator 210, and for the selected touch detection sensor (e.g., S1), a plurality of reference signals corresponding to a plurality of preselected frequencies are sequentially generated and applied by the signal generation unit 212 in the signal generator 210.

[0037] As Figure 4A shown, according to the number of touch detection sensors, one detection cycle can be divided into 3 sub-cycles. In sub-cycle 1, the sensor selection unit 213 selects the touch detection sensor S1, and for S1, W1, W2, W3 of frequencies F1, F2, and F3 respectively are sequentially applied. In response, the touch detection sensor S1 will sequentially generate modulation signals M S1W1 , M S1W2 , and M S1W3 corresponding to frequencies F1, F2, and F3 respectively. In sub-cycle 2, the sensor selection unit 213 selects the touch detection sensor S2, and for S2, W1, W2, W3 of frequencies F1, F2, and F3 respectively are sequentially applied. In response, the touch detection sensor S2 will sequentially generate modulation signals M S2W1 , M S2W2 , and M S2W3 corresponding to frequencies F1, F2, and F3 respectively. In sub-cycle 3, the sensor selection unit 213 selects the touch detection sensor S3, and for S3, W1, W2, W3 of frequencies F1, F2, and F3 respectively are sequentially applied. In response, the touch detection sensor S3 will sequentially generate modulation signals M S3W1 , M S3W2 , and M S3W3 corresponding to frequencies F1, F2, and F3 respectively.

[0038] Thus, during one detection cycle, each touch detection sensor S1, S2, S3 generates a total of 9 modulation signals, i.e., M SiWj (i = 1 ~ 3, j = 1 ~ 3).

[0039] Figure 4B Another way of the signal generator 210 in Figure 2 applying reference signals to each touch detection sensor in the steering wheel is schematically shown.

[0040] Referring to Figure 4BThe frequency selection unit 211 in the signal generator 210 sequentially selects each of a plurality of pre-selected frequencies, and for the selected pre-selected frequency (e.g., F1), the signal generation unit 212 in the signal generator 210 generates a corresponding reference signal (e.g., W1), and for the generated reference signal (e.g., W1), the sensor selection unit 213 in the signal generator 210 sequentially applies it to each touch detection sensor.

[0041] like Figure 4B As shown, based on the number of pre-selected frequencies, a detection cycle can also be divided into three sub-cycles. In sub-cycle 1, the frequency selection unit 211 selects a pre-selected frequency F1, the signal generation unit 212 generates a reference signal W1 corresponding to the pre-selected frequency F1, and the sensor selection unit 213 sequentially applies the generated W1 to the touch detection sensors S1, S2, and S3. In response, the touch detection sensors S1, S2, and S3 sequentially generate a modulation signal M corresponding to frequency F1. S1W1 M S2W1 and M S3W1 In sub-cycle 2, frequency selection unit 211 selects a preselected frequency F2, signal generation unit 212 generates a reference signal W2 corresponding to the preselected frequency F2, and sensor selection unit 213 sequentially applies the generated W2 to touch detection sensors S1, S2, and S3. In response, touch detection sensors S1, S2, and S3 sequentially generate a modulation signal M corresponding to frequency F2. S1W2 M S2W2 and M S3W2 In sub-cycle 3, frequency selection unit 211 selects a preselected frequency F3, signal generation unit 212 generates a reference signal W3 corresponding to the preselected frequency F2, and sensor selection unit 213 sequentially applies the generated W3 to touch detection sensors S1, S2, and S3. In response, touch detection sensors S1, S2, and S3 sequentially generate a modulation signal M corresponding to frequency F3. S1W3 M S2W3 and M S3W3 .

[0042] Therefore, with Figure 4A Similarly, within one detection cycle, the touch detection sensors S1, S2, and S3 generate a total of 9 modulation signals, namely M SiWj (i = 1 to 3, j = 1 to 3).

[0043] Figure 5 schematically shown Figure 2 The structure of the signal detector in the image.

[0044] The signal detector 220 includes a signal receiving unit 221 and an IQ demodulation unit 222. The signal receiving unit 221 can receive the modulation signals M SiWj (i = 1, j = 1 ~ 3).

[0045] The IQ demodulation unit 222 performs IQ demodulation on the modulation signals M SiWj to obtain the capacitance value C SiWj and / or the resistance value R SiWj sensed by the touch detection sensor Si when the reference signal Wj with the frequency Fj is applied to the touch detection sensor Si. SiWj As the Q component of the IQ demodulation, the resistance value R SiWj As the I component of the IQ demodulation, the influence of the parasitic resistance can be removed, and the capacitance and / or resistance change due to the touch can be more accurately measured, thereby achieving more accurate steering wheel touch detection.

[0046] As described above, the touch detection sensors S1, S2, S3 collectively generate nine modulation signals M SiWj (i = 1 ~ 3, j = 1 ~ 3), and the IQ demodulation unit 222 performs IQ demodulation on the nine modulation signals M SiWj (i = 1 ~ 3, j = 1 ~ 3) to obtain nine sets of capacitance values C SiWj and / or resistance values R SiWj (i = 1 ~ 3, j = 1 ~ 3), including: the capacitance values C S1W1 , C S1W2 , C S1W3 and / or the resistance values R S1W1 , R S1W2 , R S1W3 sensed by the touch detection sensor S1 under the respective reference signals W1, W2, W3. S2W1 , C S2W2 , C S2W3 and / or the resistance values R S2W1 , R S2W2 , R S2W3 sensed by the touch detection sensor S2 under the respective reference signals W1, W2, W3. S3W1 , C S3W2 , C S3W3 and / or the resistance values R S3W1 , R S3W2 , R S3W3 sensed by the touch detection sensor S3 under the respective reference signals W1, W2, W3.

[0047] These capacitance values C SiWj and / or resistance values R SiWjprocessed by the signal processor 230 to determine the touch detection state sensed by each touch detection sensor and in turn the touch detection state of the steering wheel.

[0048] Figure 6 The process of determining the touch detection state of the steering wheel by the signal processor 230 based on the touch detection signals of each touch detection sensor under each reference signal in the plurality of reference signals is schematically shown in Figure 2

[0049] Referring to Figure 6 , at 610, for each touch detection sensor S1, S2, S3 in the plurality of touch detection sensors, the signal processor 230 determines the touch detection state of the touch detection sensor under each reference signal W1, W2, W3 based on the touch detection signals of the touch detection sensor under each reference signal W1, W2, W3. Specifically, the signal processor 230 determines the touch detection state of the touch detection sensor under each reference signal W1, W2, W3 based on the capacitance value C SiWj and the resistance value R SiWj derived from the demodulation by the signal detector 220. A preset threshold value of C and R for the capacitance and resistance respectively formed when the driver touches the steering wheel can be set by experiment or calculation. When the driver touches the steering wheel, the driver's hand is equivalent to one pole of the capacitance, the area of the plate electrode of the capacitance increases, resulting in an increase in the capacitance value, and the driver is equivalent to a parallelly connected resistance, resulting in a decrease in the resistance value.

[0050] In one example, the signal processor 230 determines the touch detection state of the touch detection sensor under each reference signal W1, W2, W3 based on only the capacitance value C SiWj derived from the touch detection signals.

[0051] For example, for the touch detection sensor S1, the capacitance value C S1W1 is sensed under the reference signal W1 from the demodulation by the signal detector 220. The capacitance value C S1W1 is compared with the capacitance preset threshold value C, and if the capacitance value C S1W1 is greater than or equal to C, i.e. C S1W1 ≥ C, it is determined that the touch detection state of the touch detection sensor S1 under the reference signal W1 is the hand-on state, otherwise, if the capacitance value C S1W1 is less than C, i.e. C S1W1 < C, it is determined that the touch detection state of the touch detection sensor S1 under the reference signal W1 is the hand-off state. Similarly, the capacitance value C S1W2 of the touch detection sensor S1 under the reference signal W2 and the capacitance value C S1W3 ​By comparing the capacitance value with a preset threshold C, it can be determined whether the touch detection state of touch sensor S1 under reference signals W2 and W3 is either in the "not removed from hand" state or the "removed from hand" state. Similarly, for touch sensors S2 and S3, the capacitance value C sensed under reference signals W1, W2, and W3 will be determined. S2W1 C S2W2 C S2W3 C S3W1 C S3W2 C S3W3 By comparing with the preset threshold C of the capacitor, it can be determined whether the touch detection state of touch detection sensors S2 and S3 under the reference signals W2 and W3 is the state of not leaving the hand or the state of leaving the hand.

[0052] In another example, the signal processor 230 bases its signal solely on the resistance value R in the touch detection signal. SiWj Determine the touch detection state of the touch detection sensor under each reference signal W1, W2, and W3.

[0053] With the use of capacitance value C SiWj Similarly, this can be achieved by comparing the resistance values ​​R. SiWj The touch detection state of each touch detection sensor under each reference signal W1, W2, and W3 is determined by a preset threshold R of the resistor. SiWj When R ≤ R, the touch detection sensor is determined to be in the "not removed from hand" state under the corresponding reference signal. When R SiWj When the value is greater than R, the touch detection state of the touch detection sensor under the corresponding reference signal is determined to be the off-hand state.

[0054] In yet another example, the signal processor 230 bases its signal on the capacitance value C in the touch detection signal. SiWj and resistance value R SiWj Both are used to determine the touch detection state of the touch detection sensor under each reference signal W1, W2, and W3.

[0055] For example, for touch detection sensor S1, the capacitance value C S1W1 With the predetermined threshold value C of the capacitor and the resistance value R S1W1 Compare with a predetermined resistance threshold R. When C S1W1 ≥C and R S1W1 When C ≤ R, the touch detection state of touch detection sensor S1 under reference signal W1 is determined to be the "not removed from hand" state; when C S1W1 <C and R S1W1 When >R, the touch detection state of the touch detection sensor S2 under the reference signal W1 is determined to be the off-hand state; when C S1W1 ≥C and R S1W1 >R or when C S1W1 <C and R S1W1≥ R, the touch detection state of the touch detection sensor S1 under the reference signal W1 cannot be determined. Similarly, for the touch detection sensors S2, S3, by comparing the capacitance values C SiWj (i = 2-3, j = 1-3) with a capacitance preset threshold value C, and comparing the resistance values R SiWj (i = 2-3, j = 1-3) with a resistance preset threshold value R, the touch detection state of the touch detection sensors S2, S3 under the respective reference signals W2, W3 can be determined.

[0056] At 620, for each of the touch detection sensors S1, S2, S3, the signal processor 230 determines the touch detection state of the touch detection sensors S1, S2, S3 based on the touch detection state of the touch detection sensor under the respective reference signals W1, W2, W3.

[0057] The signal processor 230 determines the touch detection state of the touch detection sensor under the respective reference signals according to the following rules: (1) in the case that the touch detection state of the touch detection sensor under the respective reference signals W1, W2, W3 are all hand-off states, the touch detection state of the touch detection sensor is determined as a hand-off state; (2) in the case that the touch detection state of the touch detection sensor under the respective reference signals W1, W2, W3 are all not hand-off states, the touch detection state of the touch detection sensor is determined as a not hand-off state; and (3) in the case that the touch detection state of the touch detection sensor under the respective reference signals W1, W2, W3 are inconsistent, the frequency of at least a part of the reference signals is marked as an interfered frequency. Incidentally, the touch detection state of the touch detection sensor can also be set to the touch detection state reflected by the majority of the reference signals according to the principle of minority yielding to majority.

[0058] For example, the touch detection state of each of the touch detection sensors S1, S2 and S3 under the respective W1, W2, W3 obtained at 610 can be as shown in Table 1.

[0059]

Table 1

[0060]

[0061] According to Table 1, the touch detection state of each of the touch detection sensors S1, S2 and S3 under the respective reference signals W1, W2, W3 are all hand-off states HO, which indicates that the touch detection sensors S1, S2 and S3 have not sensed the capacitance and / or resistance formed due to the driver touching the corresponding touch detection area.

[0062] In this case, it is determined that the touch detection states of the touch detection sensors S1, S2 and S3 are all hand-off states.

[0063] For another example, the touch detection states of the respective touch detection sensors S1, S2, S3 under the respective W1, W2, W3 obtained at 610 can be as shown in Table 2.

[0064]

Table 2

[0065]

[0066] According to Table 2, the touch detection states of the touch detection sensors S1, S3 under the respective reference signals W1, W2, W3 are all hand-off states HO, which indicates that the touch detection sensors S1, S3 do not sense the capacitance and / or resistance formed by the driver touching the respective touch detection zones Z1, Z3 under any of the preselected frequency of the reference signals. While the touch detection state of the touch detection sensor S2 under the respective reference signals W1, W2, W3 is all Non-HO, which indicates that the touch detection sensor S2 senses the capacitance and / or resistance formed by the driver touching the respective touch detection zone Z2 under any of the preselected frequency of the reference signals.

[0067] In this case, it is determined that the touch detection states of the touch detection sensors S1, S3 are hand-off states, and it is determined that the touch detection state of the touch detection sensor S2 is a Non-HO state.

[0068] For another example, the touch detection states of the respective touch detection sensors S1, S2, S3 under the respective W1, W2, W3 obtained at 610 can be as shown in Table 3.

[0069]

Table 3

[0070]

[0071] According to Table 3, the touch detection states of the touch detection sensor S1 under the reference signals W1, W2, W3 are all hand-off states HO, and it is determined that the touch detection state of the touch detection sensor S1 is a hand-off state HO. The touch detection states of the touch detection sensor S3 under the reference signals W1, W2, W3 are all hand-off states Non-HO, and it is determined that the touch detection state of the touch detection sensor S3 is a non-hand-off state Non-HO. The touch detection state of the touch detection sensor S2 under the reference signal W1, W3 is a hand-off state HO, and the touch detection state under the reference signal W2 is a non-hand-off state Non-HO, which indicates that the sensing results of the touch detection sensor S2 for different frequency reference signals are inconsistent, and thus the touch detection state of the touch detection sensor S2 cannot be determined, because: since the position of the driver's hand relative to the steering wheel 100 does not change much at the same time or within a very short period of time (for example, one detection period, about 10 ms), the touch detection state obtained by applying any preselected frequency reference signal to the same touch detection sensor should be the same. If the touch detection state obtained by applying a certain preselected frequency is different from the touch detection state obtained by applying other preselected frequencies, it is possible that the preselected frequency or the other preselected frequencies are interfered.

[0072] In this case, according to the principle of minority yielding to majority, the frequencies of a part of the reference signals reflecting a touch detection state different from the touch detection state reflected by the majority of the reference signals can be marked as interfered frequencies. For Table 3, the reference signal W2 reflects a touch detection state different from W1 and W3, and the frequency F2 of the reference signal W2 can be marked as an interfered frequency. Incidentally, according to the principle of minority yielding to majority, the touch detection state of the touch detection sensor can also be set to the touch detection state reflected by the majority of the reference signals.

[0073] It should be noted that the case of Table 3 is only an example, and a more likely case is that once a certain preselected frequency is interfered, the touch detection state determined by the reference signal of the interfered frequency for any touch detection sensor can reflect a touch detection state different from the touch detection state determined by the reference signal of other frequencies.

[0074] At 630, based on the touch detection state of each touch detection sensor of the plurality of touch detection sensors, a touch detection state of the steering wheel is determined.

[0075] The signal processor 230 determines the touch detection state of the steering wheel 100 according to the following rules: (1) when the touch detection state of each touch detection sensor is determined to be the off-hand state at 620, the touch detection state of the steering wheel is determined to be the off-hand state; (2) when the touch detection state of each touch detection sensor is determined to be the not-off-hand state at 620, or when the touch detection state of at least one touch detection sensor is determined to be the not-off-hand state and the touch detection state of the other touch detection sensors is determined to be the off-hand state at 620, the touch detection state of the steering wheel 100 is determined to be the not-off-hand state; (3) when at least one interfered frequency is marked at 620, the touch detection state of the steering wheel cannot be determined, and the marked interfered frequency is fed back to the signal generator. As an alternative to (3) here, (4) can also be considered: when at least one interfered frequency is marked at 620, for each touch detection sensor, the touch detection state of the touch detection sensor with the largest number of touch detection states is selected as the touch detection state of the touch detection sensor according to the principle of majority. In addition, in this case, when a plurality of touch detection sensors are arranged in each touch detection area, the state of the touch detection area where the touch detection sensors are located can be determined according to the touch detection states of the touch detection sensors, and then the touch detection state of the steering wheel can be finally determined according to the touch detection states of each touch detection area.

[0076] Thus, at the end of a detection period, the steering wheel touch detection device 200 can determine the touch detection state of the steering wheel to be the off-hand state, the not-off-hand state, or unable to determine the touch detection state of the steering wheel.

[0077] On this basis, the steering wheel touch detection device 200 can continuously implement a plurality of detection periods on the steering wheel, and if it is detected that the steering wheel is in the off-hand state for more than a preset off-hand threshold, for example, in 500 detection periods (10 ms per detection period, i.e. 5 seconds), the steering wheel is detected to be in the off-hand state, an alarm message is issued to remind the driver that the off-hand time has been too long, which may cause a safety accident.

[0078] As described above, the signal processor 230 feeds the marked interfered frequency to the signal generator 210, once the signal generator 210 is fed the interfered frequency, the frequency selection unit 211 in the signal generator 210 can replace the interfered frequency with a new frequency that has not been used in a predetermined period (e.g., a certain number of detection cycles, such as the last 3, 5, 10 detection cycles, etc., which is not limited in the present disclosure) to update the pre-selected frequency in the new detection cycle. For example, for Table 3, once the signal processor marks the frequency F2 as the interfered frequency at 620, in the new detection cycle, the frequency selection unit 211 selects a new frequency F4 that has not been used in the predetermined period to replace the interfered frequency F2, and the signal generation unit 212 generates updated reference signals W1, W4, W3 corresponding to the updated pre-selected frequencies F1, F4, F3. Then, the signal processor 230 determines the touch detection state of the steering wheel 100 based on the touch detection signals generated by each touch detection sensor under each updated reference signal W1, W4, W3.

[0079] In addition, as another example, even if no frequency is marked as the interfered frequency in the last detection cycle, one or more new frequencies that have not been used in the predetermined period can be used to replace one or more of the pre-selected frequencies F1, F2 and F3 in the new detection cycle, for example, the pre-selected frequencies F1, F2 and F3 are updated to F1, F4 and F5 in the new detection cycle, where F4 and F5 are different from F1, F2 and F3. In this way, the reliability of the touch detection state can be improved.

[0080] According to the steering wheel touch detection device of the embodiments of the present disclosure, the time-sharing frequency hopping principle is adopted, by applying reference signals of different frequencies to each touch detection sensor in the steering wheel, and determining the touch detection state of the steering wheel based on the touch detection state sensed by each touch detection sensor under each reference signal of each frequency, the reliability of the steering wheel touch detection is improved, which is conducive to enhancing the safety during driving of the vehicle. At the same time, by marking the interfered frequency and replacing the interfered frequency with a new frequency that has not been used in a predetermined period, the interference caused by the detection of the touch detection sensor, for example, caused by electromagnetic compatibility EMC, can be reduced.

[0081] The above describes the steering wheel touch detection device 200 according to the embodiments of the present disclosure, and the following describes the steering wheel touch detection method performed by the steering wheel touch detection device. Figure 2 to Figure 6 The steering wheel touch detection method performed by the steering wheel touch detection device is described. Since some steps or processes have been described in detail above, in order to avoid repetition, the same or similar content will be omitted below. Figure 7 to Figure 9 The steering wheel touch detection method performed by the steering wheel touch detection device is described. Since some steps or processes have been described in detail above, in order to avoid repetition, the same or similar content will be omitted below.

[0082] Figure 7A flow chart of a steering wheel touch detection method 700 according to an embodiment of the present disclosure is schematically shown, which can be performed by the steering wheel touch detection apparatus 200 described above in one detection cycle.

[0083] Reference is made to Figure 7 The method 700 for steering wheel touch detection according to an embodiment of the present disclosure comprises steps 710-740, wherein the steering wheel comprises a plurality of touch detection sensors. The plurality of touch detection sensors can be simultaneously located in one touch detection area, or can be respectively located in different touch detection areas.

[0084] In step 710, a plurality of reference signals corresponding to a plurality of preselected frequencies are generated, wherein the number of the plurality of touch detection sensors is the same as the number of the plurality of reference signals. For example, reference signals with frequencies F1, F2 and F3 are generated, and the waveforms of the reference signals can be sine wave, rectangular wave, triangular wave, etc.

[0085] In step 720, for each of the plurality of reference signals, it is applied to each of the plurality of touch detection sensors without time overlap. This means that the reference signals with different frequencies are applied to each of the plurality of touch detection sensors in time division, and the way of applying the reference signals includes but is not limited to the two ways described above in connection with Figure 4A and Figure 4B Each of the plurality of touch detection sensors modulates the reference signal applied thereto to generate a corresponding modulated signal.

[0086] In step 730, for each of the plurality of reference signals, the modulated signal generated by each of the plurality of touch detection sensors is detected and demodulated to obtain a touch detection signal of each of the plurality of touch detection sensors under the reference signal. As an example of this step, the modulated signal can be IQ demodulated using IQ demodulation technology, and each touch detection signal obtained includes a capacitance value and / or a resistance value sensed by the touch detection sensor, wherein the capacitance value is the Q component of the IQ demodulation, and the resistance value is the I component of the IQ demodulation, so that the influence of parasitic resistance can be removed, and the capacitance and / or resistance changes due to touch can be more accurately measured to achieve more accurate steering wheel touch detection.

[0087] In step 740, based on the touch detection signal of each of the plurality of touch detection sensors under each of the plurality of reference signals, the touch detection state of the steering wheel is determined. As an example of this step, the touch detection state of the steering wheel can be determined based on the capacitance value and / or the resistance value obtained by IQ demodulation in step 730, which will be described in detail in Figure 8 .

[0088] Figure 8 schematically shows Figure 7 the flowchart of step 740 in FIG. 7.

[0089] Referring to Figure 8 , step 740 includes three sub-steps 810-830.

[0090] In sub-step 810, for each touch detection sensor of the plurality of touch detection sensors, a touch detection state of the touch detection sensor under each reference signal is determined based on the touch detection signal of the touch detection sensor under the reference signal. As an example of this sub-step, one or both of the capacitance value and / or the resistance value indicated by the touch detection signal of the touch detection sensor under the reference signal can be compared with the corresponding predetermined capacitance threshold C and / or resistance threshold R, respectively, to determine the touch detection state of the touch detection sensor under the reference signal.

[0091] In sub-step 820, for each touch detection sensor of the plurality of touch detection sensors, a touch detection state of the touch detection sensor is determined based on the touch detection states of the touch detection sensor under each reference signal. In this sub-step, the touch detection state of the touch detection sensor is determined according to the following rules: (1) in the case that the touch detection states of the touch detection sensor under each reference signal are all off-hand states, the touch detection state of the touch detection sensor is determined to be an off-hand state; (2) in the case that the touch detection states of the touch detection sensor under each reference signal are all not off-hand states, the touch detection state of the touch detection sensor is determined to be a not off-hand state; and (3) in the case that the touch detection states of the touch detection sensor under each reference signal are inconsistent, the touch detection state of the touch detection sensor cannot be determined, and meanwhile, according to the principle of majority over minority, the frequency of a part of the reference signals of the plurality of reference signals that reflect a touch detection state different from the touch detection state reflected by the majority of the reference signals is marked as a disturbed frequency. Incidentally, according to the principle of majority over minority, the touch detection state of the touch detection sensor can also be set to the touch detection state reflected by the majority of the reference signals of the plurality of reference signals.

[0092] In sub-step 830, the touch detection state of the steering wheel is determined based on the touch detection state of each of the plurality of touch detection sensors. In this sub-step, the touch detection state of the steering wheel 100 is determined according to the following rules: (1) when the touch detection state of each of the touch detection sensors is determined to be the off-hand state in sub-step 820, the touch detection state of the steering wheel is determined to be the off-hand state; (2) when the touch detection state of each of the touch detection sensors is determined to be the on-hand state in sub-step 820, or when the touch detection state of at least one of the touch detection sensors is determined to be the on-hand state and the touch detection state of the other touch detection sensors is determined to be the off-hand state in sub-step 820, the touch detection state of the steering wheel 100 is determined to be the on-hand state; (3) when at least one of the interference frequencies is marked in sub-step 820, the touch detection state of the steering wheel cannot be determined. As an alternative to (3) here, (4) can also be considered: when at least one of the interference frequencies is marked in sub-step 820, for each touch detection sensor, the touch detection state that is presented by the touch detection sensor in the largest number is selected as the touch detection state of the touch detection sensor according to the principle of majority over minority. In addition, in this case, when a plurality of touch detection sensors are arranged in each touch detection area, the state of the touch detection area where the plurality of touch detection sensors are located can be determined according to the touch detection states of the plurality of touch detection sensors, and then the touch detection state of the steering wheel can be finally determined according to the touch detection state of each touch detection area.

[0093] The above sub-steps 810-830 are similar to the process 610-630 in which the signal processor 230 in the steering wheel touch detection device 200 shown in FIG. 2 determines the touch detection state of the steering wheel based on the touch detection signals of each of the touch detection sensors under each of the plurality of reference signals, and since the process has been described in detail above by taking Table 1, Table 2, and Table 3 as examples, no further description is given here. Figure 6

[0094] Figure 9 is a schematic flowchart that schematically shows a steering wheel touch detection method 900 according to an embodiment of the present disclosure, which is performed by the steering wheel touch detection device 200 described above in a plurality of detection cycles.

[0095] In step 910, the number of detection cycles is set to k, and the method 900 starts with k = 1.

[0096] In step 920, the method 700 described above is performed in the first detection cycle to determine the touch detection state of the steering wheel in the detection cycle.

[0097] ​In step 930, it is determined whether at least one frequency is marked as a disturbed frequency in step 920. As one case, if at least one frequency is marked as a disturbed frequency in step 920, proceed to step 940.

[0098] In step 940, the plurality of preselected frequencies is updated by replacing the disturbed frequency with a new frequency that is not used in a predetermined period (e.g., a certain number of detection periods). For example, when frequency F2 is marked as a disturbed frequency in step 920, the updated preselected frequencies are F1, F2 and F4 by replacing F2 with a new frequency F4 that is not used in the predetermined period. Then, proceed to step 950.

[0099] In step 950, the number of detection periods k is increased by 1, i.e., entering the next detection period.

[0100] Returning to step 930, as another case, if no frequency is marked as a disturbed frequency in step 920, proceed to step 960.

[0101] In step 960, it is determined whether the time that the steering wheel is in the hands-off state exceeds a preset hands-off threshold, e.g., 5 seconds, which corresponds to 500 detection periods if each detection period is 10 ms. For example, if the result of step 920 is the hands-off state in the consecutive 500 detection periods, it is determined that the time that the steering wheel is in the hands-off state has reached the preset hands-off threshold. In this case, an alarm message is issued. If it is determined that the time that the steering wheel is in the hands-off state has not exceeded the preset hands-off threshold, proceed to step 950, and the number of detection periods k is increased by 1, i.e., entering the next detection period.

[0102] The steps 920 to 960 are repeated until the alarm message is issued when the time that the steering wheel is in the hands-off state exceeds the preset hands-off threshold, so as to remind the driver that the hands-off time has been too long, which can cause a safety accident.

[0103] Although the above describes that the steering wheel includes three touch detection zones and each detection zone includes one touch detection sensor, it should be understood that the steering wheel touch detection method of the embodiments of the present disclosure is not limited thereto.

[0104] The steering wheel touch detection method of the embodiments of the present disclosure can be applied to the case where the steering wheel comprises at least one touch detection area and each detection area comprises a plurality of touch detection sensors. In this case, for the plurality of touch detection sensors in each touch detection area, the steering wheel touch detection method of the embodiments of the present disclosure can be used to determine the touch detection state of the touch detection area, i.e., whether the touch detection area is in the hand-off state or the hand-on state. That is, a plurality of reference signals respectively having different preselected frequencies are applied to the plurality of touch detection sensors in the touch detection area, the number of which is the same as that of the touch detection sensors in the touch detection area; then, the touch detection state of the touch detection area is determined based on the touch detection signals of the touch detection sensors in the touch detection area under each of the plurality of reference signals; then, the touch detection state of the steering wheel is determined based on the detection results of each touch detection area, which can be performed according to the following rules: (1) when the touch detection state of all touch detection areas is in the hand-off state, it is determined that the touch detection state of the steering wheel is in the hand-off state; (2) when the state of all touch detection areas is in the hand-on state, or when at least one touch detection area is in the hand-on state and the touch detection state of the other touch detection areas is in the hand-off state, it is determined that the touch detection state of the steering wheel is in the hand-on state; (3) when the touch detection state of at least one touch detection area cannot be determined due to at least one frequency being marked as an interference frequency, it is considered that the touch detection state of the steering wheel cannot be determined, in which case, the new frequency that has not been used in the predetermined period of time can be used to update the marked interference frequency as described above, and the updated preselected frequency can be used to perform the next detection period; as an alternative to (3) here, (4) when at least one frequency is marked as an interference frequency, for each touch detection sensor, the touch detection state of the touch detection sensor can be selected as the touch detection state of the touch detection sensor according to the principle of majority.

[0105] In addition, for the case where there are a plurality of touch detection areas and each touch detection area comprises a plurality of touch detection sensors, the number of touch detection sensors in each touch detection area can be the same or different. In the case where the number of touch detection sensors in each touch detection area is the same, the same preselected frequency can be applied to each touch detection area. In the case where the number of touch detection sensors in each touch detection area is different, different frequencies can be applied to each touch detection area.

[0106] As shown above, according to the steering wheel touch detection method of the embodiments of the present disclosure, by employing the time-sharing frequency hopping technology, the reference signals of different frequencies are applied to each touch detection sensor in the steering wheel in time non-overlapping manner, and the touch detection state of the steering wheel is determined based on the touch detection state sensed by each touch detection sensor under each reference signal of each frequency, thereby improving the reliability of the steering wheel touch detection. Meanwhile, by marking the interfered frequency and excluding the interfered frequency in the detection process, the adverse effects of EMC on the touch detection result can be reduced. Furthermore, by issuing an alarm message when it is judged that the time of the hands-off state exceeds the preset hands-off threshold, the safety accident is advantageously avoided, and the HOD function plays the expected effect.

[0107] The example embodiments of the present disclosure described in detail above are merely illustrative, rather than limiting. It should be understood by those skilled in the art that various modifications and combinations of these embodiments or features thereof can be made without departing from the principles and spirits of the present disclosure, and such modifications shall fall within the scope of the present disclosure.

Claims

1. A method for steering wheel touch detection, wherein the steering wheel comprises a plurality of touch detection sensors, the method comprising: generating a plurality of reference signals corresponding to a plurality of preselected frequencies, wherein the number of the plurality of touch detection sensors is the same as the number of the plurality of reference signals; for each of the plurality of reference signals, applying it to each of the plurality of touch detection sensors non-overlapping in time, wherein each touch detection sensor modulates the reference signal applied to it to produce a corresponding modulated signal; detecting and demodulating the modulated signal produced by each of the plurality of touch detection sensors to obtain a touch detection signal of each of the plurality of touch detection sensors under the reference signal; and determining a touch detection state of the steering wheel based on the touch detection signal of each of the plurality of touch detection sensors under each of the plurality of reference signals, wherein determining the touch detection state of the steering wheel comprises: for each of the plurality of touch detection sensors, determining a touch detection state of the touch detection sensor based on the touch detection signal of the touch detection sensor under each of the plurality of reference signals, and in the case that the touch detection state of the touch detection sensor under each of the plurality of reference signals is inconsistent, marking the frequency of at least a portion of the plurality of reference signals as an interfered frequency; updating the plurality of preselected frequencies by replacing the interfered frequency with a new frequency that has not been used in a predetermined period of time, and generating an updated plurality of reference signals corresponding to the updated plurality of preselected frequencies; and determining the touch detection state of the steering wheel based on the updated plurality of reference signals. Determining the touch detection state of the steering wheel comprises:

2. The method of claim 1, wherein, for each of the plurality of touch detection sensors, determining a touch detection state of the touch detection sensor under each of the plurality of reference signals based on the touch detection signal of the touch detection sensor under each of the plurality of reference signals; for each of the plurality of touch detection sensors, determining a touch detection state of the touch detection sensor based on the touch detection state of the touch detection sensor under each of the plurality of reference signals; and determining the touch detection state of the steering wheel based on the touch detection state of each of the plurality of touch detection sensors. 3.The method according to claim 2, the touch detection state at least comprises a hands-off state, a hands-on state, and wherein, wherein in the case that the touch detection state of each of the plurality of touch detection sensors is the hands-off state, determining the touch detection state of the steering wheel as the hands-off state. ​ 4. The method of claim 3, wherein, For each of the plurality of touch detection sensors, determining a touch detection state of the touch detection sensor based on touch detection signals of the touch detection sensor under respective reference signals of the plurality of reference signals, comprises: In a case that the touch detection states of the touch detection sensor under the respective reference signals are all off-hand states, determining the touch detection state of the touch detection sensor as an off-hand state; In a case that the touch detection states of the touch detection sensor under the respective reference signals are all not off-hand states, determining the touch detection state of the touch detection sensor as a not off-hand state.

5. The method of claim 4, further comprising: In a case that the touch detection state of the touch detection sensor is determined as an off-hand state or a not off-hand state, updating the plurality of pre-selected frequencies by replacing one or more of the plurality of pre-selected frequencies with a new frequency that is not used within a predetermined period of time; and generating an updated plurality of reference signals corresponding to the updated plurality of pre-selected frequencies one-to-one, and determining the touch detection state of the steering wheel based on the updated plurality of reference signals. The touch detection signals comprise capacitance values and / or resistance values, wherein the modulated signals generated by each of the plurality of touch detection sensors are detected and demodulated to obtain the touch detection signals of each of the plurality of touch detection sensors under the reference signals, comprises:

6. The method of claim 2, wherein, The modulated signals are IQ demodulated to obtain the capacitance values and / or resistance values sensed by each of the plurality of touch detection sensors. Determining the touch detection state of the touch detection sensor under the respective reference signals based on the touch detection signals of the touch detection sensor under the respective reference signals, comprises:

7. The method of claim 6, wherein, The capacitance values and / or the resistance values of the touch detection sensor under the respective reference signals are compared with preset threshold values to determine the touch detection state of the touch detection sensor under the respective reference signals. Generating a plurality of reference signals corresponding to a plurality of pre-selected frequencies one-to-one, and for each of the plurality of reference signals, applying it to each of the plurality of touch detection sensors without temporal overlap, comprises:

8. The method of claim 1, wherein, sequentially selecting each of the plurality of touch detection sensors; and for the selected touch detection sensor, sequentially generating and applying a plurality of reference signals corresponding to a plurality of pre-selected frequencies one-to-one. Generating a plurality of reference signals corresponding to a plurality of pre-selected frequencies one-to-one, and for each of the plurality of reference signals, applying it to each of the plurality of touch detection sensors without temporal overlap, comprises:

9. The method of claim 1, wherein, sequentially selecting each of the plurality of pre-selected frequencies, and generating a reference signal corresponding to the pre-selected frequency; and for the generated reference signal, sequentially applying it to each of the plurality of touch detection sensors. ​ 10. A device for steering wheel touch detection, the steering wheel including a plurality of touch detection sensors, the device comprising: A signal generator is configured to generate a plurality of reference signals corresponding one-to-one with a plurality of preselected frequencies, and to apply each of the plurality of reference signals to a respective touch detection sensor of the plurality of touch detection sensors in a non-overlapping manner, wherein each touch detection sensor modulates its applied reference signal to generate a corresponding modulated signal, wherein the number of the plurality of touch detection sensors is the same as the number of the plurality of reference signals. A signal detector is configured to detect and demodulate the modulation signal generated by each of the plurality of touch detection sensors to obtain the touch detection signal of each of the plurality of touch detection sensors under the reference signal. as well as The signal processor is configured to determine the touch detection state of the steering wheel based on the touch detection signals of each of the plurality of touch detection sensors under each of the plurality of reference signals. The signal processor is further configured to, for each of the plurality of touch detection sensors, determine the touch detection state of the touch detection sensor based on the touch detection signal of the touch detection sensor under each of the plurality of reference signals, and, if the touch detection states of the touch detection sensors under the various reference signals are inconsistent, mark the frequencies of at least a portion of the plurality of reference signals as interference frequencies. The signal generator is further configured to update the plurality of preselected frequencies by replacing the interfered frequencies with new frequencies that have not been used within a predetermined time period, and to generate updated reference signals corresponding one-to-one with the updated plurality of preselected frequencies; and The signal processor is further configured to determine the touch detection state of the steering wheel based on the updated plurality of reference signals.

11. The apparatus of claim 10, wherein, The signal processor determines the touch detection status of the steering wheel through the following steps: For each of the plurality of touch detection sensors, the touch detection state of the touch detection sensor under each of the plurality of reference signals is determined based on the touch detection signal of the touch detection sensor under each of the plurality of reference signals; For each of the plurality of touch detection sensors, the touch detection state of the touch detection sensor is determined based on the touch detection state of the touch detection sensor under each reference signal; as well as The touch detection state of the steering wheel is determined based on the touch detection state of each of the plurality of touch detection sensors.

12. The device according to claim 11, wherein The touch detection state includes at least the off-hand state and the on-hand state, and The signal processor determines the touch detection state of the steering wheel as being off-hand if the touch detection states of the plurality of touch detection sensors are all off-hand.

13. The apparatus of claim 12, wherein, For each of the plurality of touch detection sensors, the signal processor: determines the touch detection state of the touch detection sensor as being off-hand if the touch detection states of the touch detection sensor under the respective reference signals are all off-hand; and determines the touch detection state of the touch detection sensor as being not off-hand if the touch detection states of the touch detection sensor under the respective reference signals are all not off-hand.

14. The apparatus of claim 13, wherein, the signal generator is further configured to: update the plurality of pre-selected frequencies by replacing one or more of the plurality of pre-selected frequencies with a new frequency that has not been used within a predetermined period of time if the signal processor determines the touch detection state of the touch detection sensor as being off-hand or not off-hand; and generate an updated plurality of reference signals corresponding to the updated plurality of pre-selected frequencies. The signal processor is further configured to determine the touch detection state of the steering wheel based on the updated plurality of reference signals.

15. The apparatus of claim 11, the touch detection signals comprise capacitance values and / or resistance values, wherein wherein the signal detector comprises an IQ demodulation unit configured to IQ demodulate the modulated signals to obtain the sensed capacitance values and / or resistance values of each of the plurality of touch detection sensors. The signal processor is configured to determine the touch detection state of each of the plurality of touch detection sensors under the respective reference signals by comparing the capacitance values and / or the resistance values of the touch detection sensor under the respective reference signals with a pre-set threshold.

16. The apparatus of claim 15, wherein, The signal generator comprises:

17. The apparatus of claim 10, wherein, a frequency selection unit configured to select the plurality of pre-selected frequencies; a signal generation unit configured to sequentially generate a plurality of reference signals corresponding to the plurality of pre-selected frequencies; and a sensor selection unit configured to sequentially select each of the plurality of touch detection sensors to which the plurality of reference signals are to be applied. ​

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