Method and system for detecting a driver's hand holding / releasing a steering wheel during driving

Abstract

The present invention relates to a method and system for detecting whether a driver's hand is holding or releasing a steering wheel during driving. A driver's hand holding / release detecting system for detecting whether a driver's hand is holding or releasing a steering wheel during driving is applied to a vehicle. When a controller operates a driving assist system during driving, the driver's hand holding / release detecting system compares a representative value of MDPS torque and a representative value of vehicle measurement data as a ratio of representative values between sensors, and divides a disturbance traveling area and a normal traveling area by the magnitude of the ratio of representative values between sensors to perform sensor detection correction control for hand holding / release confirmation by applying a disturbance torque threshold to a torque filtered value, or torque-based detection control for hand holding / release confirmation by applying an upper / lower torque limit value to a torque filtered value, thereby reducing hand holding / release detection errors during driving using only on-vehicle sensors without using a capacitive sensor.

Description

Technical Field

[0001] The present invention relates to a method and system for detecting a driver’s hands gripping / releasing the steering wheel during driving, and more specifically, to a system that detects hand gripping / releasing during operation of a driver assistance system without utilizing capacitive sensors. Background Technology

[0002] Typically, the Automatically Commanded Steering Function (ACSF) used in vehicles continuously detects whether the driver is holding the steering wheel (i.e., hands on / off) to confirm lane keeping functionality while the driver assistance system is in operation during vehicle movement, and specifies that an alert should be issued when the driver's hands leave the steering wheel during the operation of the driver assistance system.

[0003] Accordingly, driver assistance systems (which must detect whether the driver's hands are on or off the steering wheel) could include, for example, lane keeping assist (LKA) and lane following assist (LFA). In this case, LKA only operates when there is a risk of lane departure, while LFA always operates.

[0004] Therefore, when the system is running, LKA and LFA require driver hand grip / release detection functionality. An example of meeting these requirements is a driver hand grip / release detection functionality that utilizes a sensor application to detect the direct method and a post-processing calculation to determine the indirect method.

[0005] For example, a direct sensor-based detection method involves mounting a capacitive sensor on the steering wheel and directly using the capacitive sensor to determine whether the driver's hands are gripping or releasing the steering wheel. A post-processing calculation-based indirect determination method involves receiving the driver's torque input from the Electronic Motor Driven Power Steering System (MDPS), post-processing the torque sensor's measurement to generate an additional torque, and using the torque sensor's value to indirectly determine whether the driver's hands are gripping or releasing the steering wheel.

[0006] However, the post-processing calculation indirect determination method, which uses the torque sensor of MDPS to determine whether the hand is gripping or releasing, has the following limitations.

[0007] For example, post-processing calculations indirectly determine the torque by monitoring the absolute amount and change of torque measured by the torque sensor of the MDPS. However, in this method, noise may be transmitted to the torque measurement due to surrounding road conditions (e.g., driving conditions such as passing through obstacles, manholes, etc.).

[0008] Specifically, in the case of such torque measurement noise, it is possible to use only one sensor to detect whether the driver's hand is gripping or releasing. If the threshold for determining hand release is set too low, hand release may be incorrectly detected as hand gripping, potentially violating the law. On the other hand, if the threshold is set too high, hand gripping may be incorrectly detected as hand release, triggering a hand release alarm and leading to customer complaints. Summary of the Invention

[0009] Therefore, the object of the present invention is to provide a method and system for detecting a driver's hands gripping / releasing the steering wheel during driving, which significantly improves the performance of driver's hands gripping / releasing detection during driving by using a torque sensor of MDPS, enabling the provision of driver's hands gripping / releasing information required in the operation of the driver assistance system without using capacitive sensors. Specifically, by using the measurements of longitudinal acceleration sensors and wheel speed sensors (which are basic detection devices for vehicles) as interference or external noise, and applying correction processing to the post-processing results of torque sensor measurements, the error of the detection values ​​is reduced because the driver's hands gripping / releasing detection is divided into interference driving areas and normal driving areas.

[0010] The method according to the present invention for detecting a driver's hand gripping / releasing the steering wheel during driving includes: a sensor detection step, which, while the vehicle is in motion and a driving assistance system is being operated by a controller, calculates a representative value of the torque detection value of the torque sensor and a representative value of the vehicle measurement data of the sensor detection value of the on-board sensor by frequency filtering; an interference variable selection step, which calculates the ratio of the representative values ​​between the sensors as the ratio of the representative value of the torque sensor to the representative value of the vehicle measurement data; an interference condition confirmation step, which, after confirming the torque sensor detection value, divides the interfering driving area and the normal driving area by the magnitude of the ratio of the representative values ​​between the sensors; and a detection logic binarying step, which changes the torque filter value applied to the torque sensor detection values ​​of the interference-based detection step and the torque-based detection step, wherein the interference-based detection step detects the driver's hand gripping or releasing in the interfering driving area, and the torque-based detection step detects the driver's hand gripping or releasing in the normal driving area.

[0011] In a preferred embodiment, the driving assistance system is a lane keeping assist (LKA) system that returns the vehicle to the lane when it leaves the lane, or a lane following assist (LFA) system that enables the vehicle to travel along the center of the lane.

[0012] In a preferred embodiment, the on-board sensors are a longitudinal acceleration sensor for detecting the longitudinal acceleration of the vehicle and a wheel speed sensor for detecting the wheel speeds of the left / right front wheels and the left / right rear wheels of the vehicle.

[0013] In a preferred embodiment, the sensor detection step is performed as follows: extracting interference frequency signals by performing frequency filtering preprocessing on the torque sensor detection values ​​and the sensor detection values ​​in real time; and determining the vehicle measurement data representative value and the MDPS torque representative value by selecting representative values ​​from the interference frequency signals.

[0014] In a preferred embodiment, a representative value is selected by applying any one of the peak-to-peak, total level, and amplitude to the interference frequency signal.

[0015] In a preferred embodiment, the interference variable selection step is performed by: obtaining the dispersion of the MDPS torque representative value and the vehicle measurement data representative value, linearizing the dispersion, calculating the ratio of the vehicle measurement data representative value to the MDPS torque representative value based on the linearization result, and calculating the ratio of the representative values ​​between the sensors as the ratio calculation value.

[0016] In a preferred embodiment, the ratio of representative values ​​between sensors is calculated by applying a threshold margin to the comparison value calculation.

[0017] In a preferred embodiment, the interference condition confirmation step uses the torque sensor threshold (the ratio of the torque sensor detection value to the representative value between the sensors) as a variable to define the interference driving threshold, and divides the interference driving area and the normal driving area according to the magnitude of the variables.

[0018] In a preferred embodiment, the interference driving zone is the situation where the torque sensor detection value is greater than the torque sensor threshold and the ratio of the representative values ​​between the sensors is greater than the interference driving threshold, while the normal driving zone is the situation where the torque sensor detection value is greater than the torque sensor threshold, but the ratio of the representative values ​​between the sensors is less than the interference driving threshold.

[0019] In a preferred embodiment, the interference-based detection step is performed by: applying an interference torque threshold to the torque filter value of the torque detection value; comparing the torque filter value with the interference torque threshold; identifying a hand gripping confirmation when the torque filter value is less than the interference torque threshold; and identifying a hand release confirmation when the torque filter value is greater than the interference torque threshold.

[0020] In a preferred embodiment, when the torque filter value is greater than the interference torque threshold, a hold-hold detection hold mode is applied to confirm the hold.

[0021] In a preferred embodiment, torque-based detection is performed by: applying a torque threshold and a torque change rate to a torque filter value of the torque detection value; comparing the torque filter value with either the torque threshold or the torque change rate; identifying a hand grip confirmation when the torque filter value is less than either the torque threshold or the torque change rate; and identifying a hand release confirmation when the torque filter value is greater than either the torque threshold or the torque change rate.

[0022] In a preferred embodiment, the alarm light is activated upon recognizing the confirmation that the hand has been released.

[0023] Furthermore, the driver's hand grip / release detection system of the present invention for achieving the objective includes: a controller, a longitudinal acceleration sensor, a wheel speed sensor, and a torque sensor. The controller is configured to: during vehicle operation and while the driver assistance system is running, calculate the ratio between the representative values ​​of the MDPS torque of the torque detection value calculated through frequency filtering and the representative value of the vehicle measurement data of the sensor detection value; upon confirmation of the torque detection value, divide the interfering driving area and the normal driving area by the magnitude of the ratio between the representative values ​​of the sensors; execute sensor detection correction control or torque-based detection control, wherein sensor detection correction control identifies hand grip / release confirmation on the steering wheel by applying an interference torque threshold to the torque filter value of the torque detection value in the interfering driving area, and torque-based detection control identifies hand grip / release confirmation on the steering wheel by applying an upper torque limit value and a lower torque limit value to the torque filter value of the torque detection value in the normal driving area; the longitudinal acceleration sensor and the wheel speed sensor detect the sensor detection values ​​and transmit them to the controller; the torque sensor is mounted on the MDPS and detects the torque detection values ​​and transmits them to the controller.

[0024] In a preferred embodiment, the controller is connected to the warning light, and the controller turns on the warning light when it is confirmed that the steering wheel has been released.

[0025] The driver's hand grip / release detection control implemented in the vehicle driver's hand grip / release detection system of the present invention provides the following advantages during driving.

[0026] First, even without using a capacitive sensor directly mounted on the steering wheel, information regarding the driver's hand grip / release on the steering wheel can be provided to determine when lane-keeping assist intervenes during driving. Second, by utilizing existing onboard sensors and the torque sensor from MDPS, the accuracy of driver hand grip / release detection is improved when only the torque sensor is used. Third, by utilizing measurements from the steering column torque sensor, vehicle accelerometer, and vehicle wheel speed sensor—in the onboard sensors used to determine interference areas generated by external noise—errors in driver hand grip / release detection can be significantly reduced by separating noise conditions from normal driving conditions. Fourth, since hand grip / release can be determined independently using interference areas, the freedom to apply existing hand grip / release thresholds during normal driving is further increased, thereby reducing customer complaints due to false hand release detection in principle. Fifth, the freedom to set parameters is increased because hand release detection logic can be applied separately according to interference conditions and normal driving conditions. Sixth, since it can suppress false hand gripping in the event of interference, it can reduce the possibility of violating the laws and regulations of Automatic Command Steering Function (ACSF) due to false hand gripping when the hand is released. Attached Figure Description

[0027] Figure 1A and Figure 1B This is a flowchart of a method according to the present invention for detecting a driver's hand gripping / releasing during vehicle operation.

[0028] Figure 2 An example is shown of applying a driver's hand grip / release detection system according to the present invention, which implements improved control of driver's hand grip / release detection performance during driving, to a vehicle.

[0029] Figure 3 The diagram illustrates the status of longitudinal acceleration measurements from an onboard sensor and torque measurements from an MDPS torque sensor during turbulent driving, according to the present invention.

[0030] Figure 4 An example of peak-to-peak calculation of a frequency signal for selecting a representative value of MDPS torque from representative values ​​of vehicle measurement data, according to the present invention, is shown.

[0031] Figure 5 An example of the discreteness and linearization processing of longitudinal acceleration measurements and MDPS torque measurements for setting thresholds during normal vehicle operation, according to the present invention, is shown.

[0032] Figure 6 An example of a diagram according to the invention for determining disturbances applied during actual vehicle operation is shown.

[0033] Figure 7 An example of the MDPS torque diagrams before and after holding / releasing a low-frequency filter during driving, according to the present invention, is shown. Detailed Implementation

[0034] It should be understood that the term "vehicle" or "of a vehicle" or other similar terms as used herein generally include motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, and various commercial vehicles, boats including various vessels and ships, aircraft, etc., and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., vehicles derived from non-fossil fuels). As mentioned herein, a hybrid vehicle is a vehicle with two or more power sources, such as both gasoline and electric power.

[0035] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will also be understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of the stated feature, value, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, values, steps, operations, elements, components, and / or groups thereof. As used herein, the term “and / or” includes any and all combinations of one or more related listed items. Throughout the specification, unless explicitly stated otherwise, the word “comprising” and variations such as “including” or “comprising” should be understood to imply the inclusion of the stated element, but do not exclude any other element. Furthermore, the terms “unit,” “device,” “component,” and “module” described in the specification mean a unit for performing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0036] Furthermore, the control logic of the present invention can be implemented as a non-volatile computer-readable medium on a computer-readable medium, which contains executable program instructions that are executed by a processor, controller, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer-readable medium can also be distributed on a network-connected computer system, such that the computer-readable medium is stored and executed in a distributed manner, for example, via a telematics server or a controller area network (CAN).

[0037] Hereinafter, exemplary embodiments of the invention will be described in detail with reference to the accompanying exemplary drawings. These exemplary embodiments are illustrative examples and can be implemented in various different forms by those skilled in the art to which this invention pertains, and are therefore not limited to the exemplary embodiments described herein.

[0038] refer to Figure 1A and Figure 1B The method for detecting whether the driver's hands are on or off the steering wheel during driving is implemented as follows: while the vehicle is in motion, the controller (see...) Figure 2 During the operation of the driver assistance system (S10), for the interference driving area (S50-1) and normal driving area (S50-2) divided by calculating the ratio of the detection values ​​of the torque sensor and the vehicle sensor (S10-30), the torque sensor detection value of the torque sensor that detects whether the driver's hand is gripping or releasing is applied differently (S40-S70).

[0039] For example, different applications of torque sensor detection values ​​are used during the operation of the driver assistance system to confirm the torque detection values ​​of the torque sensor set in the electric motor driven power steering system (MDPS), and different applications of torque sensor detection values ​​are executed through detection logic binary control. The detection logic binary control changes the torque filter value applied to the torque sensor detection values ​​of interference-based detection or torque-based detection. Interference-based detection detects the driver's hand gripping or releasing in the interference area, while torque-based detection detects the driver's hand gripping or releasing in the normal driving area.

[0040] Specifically, in the operating state (S10) of the driver assistance system (i.e., in the active state), after executing the interference variable selection step (S30) through the sensor detection step (S20), the interference condition (S40) confirms the interference driving area (S50-1) and the normal driving area (S50-2), and thereby executes the detection logic binary control (S60-1, S70). The detection logic binary control changes the torque filter value of the torque sensor detection value applied to the interference-based detection (S60-1) and the torque-based detection (S70). The interference-based detection (S60-1) detects the driver's hand gripping or releasing in the interference driving area (S50-1), and the torque-based detection (S70) detects the driver's hand gripping or releasing in the normal driving area (S50-2).

[0041] In this situation, the driving assistance system in operation (S10) indicates lane keeping control and lane following assist control. In this case, the activation of the driving assistance system is confirmed by checking the vehicle's driving status or by pressing the driving assistance button.

[0042] Specifically, the sensor detection step (S20) is related to the MDPS torque sensor, which uses an acceleration sensor and a wheel speed sensor as interference detection devices, and the interference variable selection control (S30) simultaneously considers the acceleration sensor, the wheel speed sensor, and the MDPS torque sensor.

[0043] Furthermore, the detection logic binary control (S60-1, S70) performs the driver's hand release detection on the steering wheel using any one of interference-based detection (S60-1), interference-based detection hold (S60-1), and torque-based detection (S70). Therefore, interference-based detection (S60-1) and torque-based detection (S70) can eliminate the influence of interference on the hand release detection of the MDPS torque sensor by applying different MDPS torque values.

[0044] Therefore, the driver's hand grip / release detection method during driving can independently determine hand grip / release in the interference area, increasing the freedom to set the threshold for hand release determination during normal driving without interference. Since keeping the driver's hand gripped can suppress false detections when the driver assistance system is running under interference, detection performance can be improved, reducing the possibility of violating the law due to false detections of hand gripping after hand release. Furthermore, since false detection variables can be considered separately for interfering driving and normal driving, the freedom to set the parameters of the hand release detection logic can be increased.

[0045] As a result, with the MDPS torque sensor used as is for lane keeping control and lane following assist control, the method of detecting the driver's hand grip / release during driving can improve the accuracy of the logic for detecting the driver's hand grip / release.

[0046] refer to Figure 2 The vehicle 1 includes a driver's hand grip / release detection system 10 connected to the driver assistance system 5.

[0047] Specifically, the driver assistance system 5 includes a Lane Keeping Assist System (LKA) 5A and / or a Lane Following Assist System (LFA) 5B. In this case, the vehicle 1 may include a driver assistance button to activate the driver assistance system 5, or may determine the vehicle's driving status (e.g., constant speed driving or cruise driving).

[0048] For example, LKA 5A operates only when there is a risk of lane departure, such as when a vehicle 1 traveling at a predetermined speed (e.g., 60 km / h) deviates from its lane and performs the function of bringing the vehicle 1 back into the lane, while LFA 5B always operates, such as when it performs the function of enabling the vehicle 1 to travel along the center of the lane by recognizing the lane ahead and the vehicle 1.

[0049] Specifically, the driver's hand grip / release detection system 10 includes a vehicle sensor 20, a controller 30, and a warning light 40.

[0050] For example, vehicle sensor 20 is divided into on-board sensor 20-1 and torque sensor 20-2. On-board sensor 20-1 is longitudinal acceleration sensor 21 and wheel speed sensor 22, and torque sensor 20-2 is an MDPS torque sensor installed on the electric motor driven power steering system (MDPS) 3.

[0051] Therefore, the longitudinal acceleration sensor 21 detects the longitudinal acceleration in the longitudinal direction (i.e., the x direction in the xyz coordinate system) of the vehicle 1, the wheel speed sensor 22 is installed on each of the left / right front wheels (FL / FR) and left / right rear wheels (RL / RR) of the vehicle 1 to detect the wheel speed, and the torque sensor 20-2 detects the magnitude of the steering torque generated when the driver grips and rotates the steering wheel.

[0052] For example, the controller 30 operates as a central processing unit (i.e., CPU), which, in conjunction with memory, performs data detection, calculation, and estimation for control. The following logic is stored in memory through programming: confirmation of the operating status of the driving assistance system (S10), sensor detection (S20), variable selection control (S30), determination of interference conditions (S40), confirmation of interference / normal driving area (S50-1, S50-2), sensor detection correction control (S60-1), sensor detection hold control (S60-1), sensor detection control (S70), etc.

[0053] Therefore, the controller 30 includes: a signal processing unit 31, a ratio calculation unit 32, a driving area determination unit 33, and a signal output unit 34.

[0054] For example, a warning light 40 is located in the driver's side instrument cluster of vehicle 1 and issues an alert when the driver's hands are released from the steering wheel while the driver assistance system is in operation. The warning light 40 can be implemented using a buzzer or a light-emitting diode (LED) light.

[0055] In the following text, reference will be made to Figures 2 to 7 To describe in detail Figure 1A and Figure 1B A method for detecting when a driver's hands are gripping or releasing them during driving. In this case, the control unit is the controller 30, and the controlled object is a component of the driver's hands gripping / releasing detection system 10.

[0056] First, the controller 30 executes step S10 of entering the driving assistance system. This step can be executed by recognizing constant speed driving and / or cruise driving in the driving information of the vehicle 1 or by button operation for driving assistance actions, or by the detection information of the engine rpm sensor or vehicle speed sensor in the on-board sensor 20-1.

[0057] As a result, when the driving assistance system is put into operation (S10), if the condition of vehicle 1 is met, the LKA 5A and / or LFA 5B of the driving assistance system 5 are in operation (i.e., in an active state).

[0058] Subsequently, the controller 30 enters the sensor detection step (S20) and performs the sensor detection step (S20) as follows: driver's hand gripping / releasing sensor confirmation step S21, vehicle sensor measurement value preprocessing step S22, interference frequency signal extraction step S23, vehicle measurement data representative value selection step S24, and MDPS torque representative value selection step S25.

[0059] refer to Figure 2 The controller 30 confirms the longitudinal acceleration sensor 21, wheel speed sensor 22 and torque sensor 20-2 in the signal processing unit 31. The signal processing unit 31 receives the activation (i.e., operation on) signal of LKA 5A and / or LFA 5B, and the controller 30 reads and confirms the longitudinal acceleration detection value of the longitudinal acceleration sensor 21, the wheel speed detection value (or wheel rpm detection value) of the wheel speed sensor 22 for all or at least one of the left / right front wheels and left / right rear wheels, and the steering torque detection value of the torque sensor 20-2.

[0060] For example, the driver's hand grip / release determination sensor confirmation (S21) can increase the determination of the disturbance generation conditions by utilizing one or more sensor information from the acceleration sensor (x direction) and wheel speed sensors (FR, FL, RR, RL) already installed in the vehicle's sensors, while maintaining the existing hand grip / release determination method using the MDPS torque sensor as is.

[0061] For example, vehicle sensor measurement preprocessing (S22) is performed by filtering the signal using a frequency filter, which has the characteristics of... Figure 3The appropriate frequency bands for the high-frequency and x-direction acceleration of the MDPS torque sensor are confirmed. Interference frequency signal extraction (S23) is performed using the sensor interference frequency signal and the MDPS interference frequency signal obtained from the frequency filter. Therefore, the filtered interference frequency signal is the result of filtering the high-frequency and x-direction acceleration of the MDPS torque sensor, and the confirmation and filtering of the detected values ​​are performed in real time while the vehicle is in motion, so that multiple different amplitudes are extracted until the release of the hand is detected.

[0062] For example, the vehicle measurement data representative value selection (S24) selects a representative sensor interference frequency signal from the sensor interference frequency signal as the vehicle measurement data representative value, and the MDPS torque representative value selection (S25) selects a representative MDPS interference frequency signal from the MDPS interference frequency signal as the MDPS torque representative value.

[0063] refer to Figure 3 The diagram shows a frequency graph in which the x-direction acceleration (i.e., longitudinal acceleration) measured by vehicle sensors when the vehicle is traveling under disturbance conditions is compared with the MDPS torque.

[0064] As shown in the figure, because the interference transmitted to vehicle 1 due to obstacles, stones, manholes, etc., begins with the impact on the wheels, when the signal strength of the longitudinal wheel speed sensor 22 and the longitudinal acceleration sensor 21 is compared with the signal strength of the torque sensor 20-2 of the MDPS 5, the signal strength of the on-board sensor 20-1, which is displayed as an acceleration frequency diagram in the x direction, is greater than the signal strength of the torque sensor 20-2, which is displayed as an MDPS torque frequency diagram, and a relatively high frequency signal is generated at this signal strength.

[0065] As a result, the impact of the wheels through the left / right front wheels (FL / FR) and left / right rear wheels (RL / RR) propagates throughout the vehicle, causing interference to the vehicle 1 due to obstacles, stones, manholes, etc., and the resulting interference is measured by the longitudinal acceleration sensor 21, wheel speed sensor 22 and torque sensor 20-2, thus serving as the cause of false detection of hand gripping when the hand is released.

[0066] refer to Figure 4 An example is shown where a representative MDPS torque value is selected by applying peak-peak to the frequency signal in the MDPS interference frequency signal. Thus, it can be seen that a representative value of the vehicle measurement data is also selected by applying peak-peak to the frequency signal. In this case, since the peak-peak application method is a conventional technique, a detailed description is omitted.

[0067] Furthermore, the representative values ​​for MDPS torque and vehicle measurement data can be selected by applying the total level to the frequency band or the amplitude to the frequency signal. In this case, since the methods for applying the total level and the amplitude are conventional techniques, detailed descriptions are omitted.

[0068] Next, the controller 30 enters the disturbance variable selection step (S30), and performs the disturbance variable selection step (S30) as a representative value linearization processing step (S31) and a ratio calculation step of representative values ​​between sensors (S32).

[0069] refer to Figure 2 The controller 30 performs representative value linearization processing (S31) and ratio calculation between representative values ​​of the sensors (S32) by exchanging information with the ratio calculation unit 32 connected to the signal processing unit 31.

[0070] refer to Figure 5 The representative value linearization process (S31) obtains the dispersion for each of the MDPS torque representative value (e.g., labeled as MDPS torque) and the vehicle measurement data representative value (e.g., labeled as LONG ACCEL), and performs it by linearizing the dispersion.

[0071] Additionally, the calculation of the ratio of representative values ​​between sensors (S32): The ratio of values ​​is calculated by comparing the vehicle measurement data representative value with the MDPS torque representative value, which are respectively linearized, and the threshold value of the calculated ratio is then multiplied by a margin to be used as the normal threshold for normal driving. In this case, the size of the margin is determined by calculating the ratio between normal driving conditions and disturbed driving conditions during vehicle development, and considering the ratio that can be used as the limit of the normal driving range.

[0072] Then, the controller 30 performs interference condition verification (S40). Interference condition verification is performed by applying the following interference condition verification formula (S40).

[0073] Interference condition confirmation formula: A>a? & B>b?, a=M×K Here, "A" is the ratio of representative values ​​between sensors obtained by calculating the ratio of representative values ​​between sensors (S32), "a" is the interference driving threshold of the ratio of representative values ​​between sensors, "B" is the detection value of the MDPS torque sensor, "b" is the threshold of the MDPS torque sensor, "M" is the margin value considering noise, "K" is the ratio of representative values ​​set by the sensors, ">" is an inequality indicating the magnitude relationship between two values, and "&" indicates the sum condition of two values.

[0074] Therefore, in the interference condition confirmation (S40), the ratio A of the representative values ​​between the sensors obtained in real time during vehicle operation is compared with the interference driving threshold (i.e., the predetermined value) a, and the MDPS torque sensor detection value B is compared with the MDPS torque sensor threshold (i.e., the predetermined value) b.

[0075] As a result, after confirming that the MDPS torque sensor detection value B is greater than the MDPS torque sensor threshold b by "B > b", and confirming that the ratio A of the representative values ​​between the sensors is greater than the interference driving threshold a by "A > a", it is determined that the current driving state of vehicle 1 is in the interference driving area (S50-1).

[0076] On the other hand, if it is confirmed by “B>b” that the MDPS torque sensor detection value B is greater than the MDPS torque sensor threshold b, but it is not confirmed by “A>a” that the ratio A of the representative values ​​between the sensors is greater than the interference driving threshold a, then it is determined that the current driving state of vehicle 1 is in the normal driving area (S50-2).

[0077] refer to Figure 6 The interference driving determination diagram shows that the interference driving threshold 'a' is set to the Z-line value of 0.73. When this value is greater than 0.73, interference driving is determined; when this value is less than 0.73, normal driving is determined.

[0078] Therefore, it can be seen that, based on a value of 0.73, the hand grip / release logic in the interference area can be identified as a logic separate from the hand grip / release logic in the normal driving area.

[0079] Finally, the controller 30 performs an interference-based detection step (S60-1) or an interference-based detection hold step (S60-1) in the interference driving area (S50-1), and performs a torque-based detection step (S70) in the normal driving area (S50-2).

[0080] refer to Figure 2 The controller 30 outputs the signal of the driving area determination unit 33 to the outside through the driving area determination unit 33 and the signal output unit 34, which exchange information with the ratio calculation unit 32.

[0081] Therefore, the driving area determination unit 33 will Figure 6 The interference driving determination map is stored in the memory to determine interference driving and normal driving, and during the operation of LKA 5A and / or LFA 5B, the signal output unit 34 outputs a signal to the warning light 40 to indicate the driver's hand has been removed from the steering wheel.

[0082] Specifically, the interference-based detection step (S60-1) is performed through the hand release detection interference mode step (S61), the interference variable condition satisfaction confirmation step (S62), the hand holding confirmation step (S63), and the hand release confirmation step (S64).

[0083] As an example, the hand release detection interference mode (S61) indicates entering the interference-based detection step, and the interference variable condition is satisfied (S62) to apply the following interference false detection determination formula.

[0084] Formula for determining interference false detection; F < f? Here, "F" is the torque filter value (i.e., the value after filtering by the MDPS low-frequency filter), and "f" is the interference torque threshold.

[0085] Specifically, the disturbance torque threshold f can be applied as an absolute value of approximately 1 Nm or less. However, in situations involving disturbance, the driver's grip force on the steering wheel may change, affecting the torque detection value; therefore, the disturbance torque threshold f of 1 Nm or less can be set differently. Thus, the specific value applied as the disturbance torque threshold f should be treated as an example.

[0086] As a result, in “F>f”, if the torque filter value F is less than the interference torque threshold f, then the hand grip confirmation is executed (S63), while in “F>f”, if the torque filter value F is greater than the interference torque threshold f, then the hand release confirmation is executed (S64), thereby turning on the alarm light 40.

[0087] On the other hand, the interference-based detection hold step (S60-1) is converted to a hand grip detection hold mode. Therefore, hand grip confirmation is not performed, and feedback is sent to the driver's hand grip / release determination sensor confirmation step S21. In this case, sensor detection hold control (S60-1) can be applied when the torque filter value F is approximately at least 1.5 times the absolute value of the torque threshold f (i.e., 1.5 Nm or more).

[0088] Therefore, the interference-based detection hold step (S60-1) does not proceed from the interference variable condition satisfaction confirmation step (S62) of the interference-based detection step (S60-1) to the hand release confirmation step (S64), but can directly feed back to the driver's hand grip / release determination sensor confirmation step (S21).

[0089] Specifically, the torque-based detection step (S70) is executed as the normal mode step for hand release detection (S71), the MDPS torque variable confirmation step (S72), the hand grip confirmation step (S73), and the hand release confirmation step (S74).

[0090] For example, the normal mode for hand release detection (S71) indicates that the torque-based detection step has been entered, and the MDPS torque variable confirmation (S72) applies the following torque-based detection determination formula.

[0091] The formula for determining torque detection is: D < d? or E < e? Here, "D" is the torque detection value, "d" uses approximately 0.5 Nm as the torque threshold, "E" is the torque change rate, and "e" uses approximately 10 Nm as the torque change rate threshold.

[0092] As a result, in the case of "D < d", when the torque detection value D detected and calculated by the torque sensor (20-2) of MDPS 5 is less than the torque threshold d, or in the case of "E < e", when the torque change rate E is less than the torque change rate threshold e, a hand grip confirmation (S73) is executed, and when both values ​​are large, a hand release confirmation (S74) is executed, thereby turning on the warning light 40.

[0093] refer to Figure 7 Based on the frequency diagram of MDPS torque before / after low-frequency filtering when interference occurs, the simulation results of the difference between interference-based detection (S60-1) and torque-based detection (S70) can be seen in Table 1 below.

[0094] [Table 1] Therefore, the torque value of the MDPS torque sensor 20-2 is confirmed differently when the hand is released and when the hand is held. Thus, it is demonstrated that even when using the MDPS torque sensor 20-2 as is, the accuracy and reliability of the MDPS torque value are significantly improved compared to conventional technology.

[0095] As described above, in the method for detecting driver's hand grip / release during driving in the driver's hand grip / release detection system 10 applied to vehicle 1 according to this embodiment, when vehicle 1 is driving, during the operation of the driving assistance system 5 by the controller 30, the MDPS torque representative value of the torque detection value calculated by frequency filtering and the vehicle measurement data representative value of the sensor detection value are calculated as the ratio of the representative values ​​between the sensors. When the torque detection value is confirmed, the interference driving area (S50-1) and the normal driving area (S50-2) are divided by the magnitude of the ratio of the representative values ​​between the sensors, and sensor detection correction control (S60-1) is executed, wherein hand grip / release confirmation is identified by applying an interference torque threshold to the torque filter value of the torque detection value in the interference driving area (S50-1), or torque-based detection control (S70) is executed, wherein hand grip / release confirmation is identified by applying an upper torque limit value and a lower torque limit value to the torque filter value of the torque detection value in the normal driving area (S50-2).

[0096] Therefore, the driver's hand grip / release detection system 10 can reduce hand grip / release detection error by dividing the interfering driving area and the normal driving area, without using a capacitive sensor. Specifically, it reduces hand grip / release detection error by taking the measured values ​​of the longitudinal acceleration sensor 21 and wheel speed sensor 22 of the vehicle sensor 20-1, which are the basic sensing devices of the vehicle 1, as the post-processing result of the torque sensor measurement value to correct for interference (or external noise).

Claims

1. A method for detecting when a driver's hands are on / off the steering wheel while the vehicle is in motion, comprising: During the operation of the driver assistance system, the controller divides the interfering driving area and the normal driving area by calculating the ratio between the detection values ​​of the torque sensor and the vehicle sensor. In the interference driving area and the normal driving area, the torque sensor detection value is applied differently by the controller, and the torque sensor detects whether the driver's hand is gripping or releasing the hand; The torque sensor detection values ​​are obtained by applying them in different ways as follows: During the operation of the driver assistance system, confirm the torque detection value of the torque sensor set on the MDPS; The detection logic is binary control, which applies the torque filter value to the disturbance-based detection and applies the torque detection value or torque change rate to the torque-based detection. The disturbance-based detection detects whether the driver's hand is gripping or releasing in the disturbance driving area, while the torque-based detection detects whether the driver's hand is gripping or releasing in the normal driving area. The binary control of the detection logic includes: The sensor detection step calculates the MDPS torque representative value by performing frequency filtering on the torque detection value of the torque sensor, and calculates the vehicle measurement data representative value by performing frequency filtering on the sensor detection value of the vehicle sensor. The interference variable selection step calculates the ratio of representative values ​​between sensors as the ratio of the MDPS torque representative value to the vehicle measurement data representative value. The interference condition confirmation step, after confirming the torque sensor detection value, divides the interference driving area and the normal driving area by the ratio of the representative values ​​between the sensors. The detection logic binary step applies torque filter values ​​differently after dividing the detection into interference-based detection and torque-based detection.

2. The method according to claim 1, wherein, The vehicle-mounted sensors are a longitudinal acceleration sensor for detecting the longitudinal acceleration of the vehicle and a wheel speed sensor for detecting the wheel speeds of the left / right front wheels and the left / right rear wheels of the vehicle.

3. The method according to claim 1, wherein, The sensor detection step is performed as follows: Interference frequency signals are extracted by preprocessing the torque sensor detection values ​​and sensor detection values ​​in real time with frequency filtering. The representative values ​​for vehicle measurement data and MDPS torque are determined by selecting representative values ​​from the interference frequency signals.

4. The method according to claim 3, wherein, The representative value is determined by applying any one of peak-to-peak, total level, and amplitude to the interference frequency signal.

5. The method according to claim 1, wherein, The interference variable selection step is performed as follows: Obtain the dispersion of the representative value of MDPS torque and the representative value of vehicle measurement data, and linearize the dispersion; The ratio of the representative value of the vehicle measurement data to the representative value of the MDPS torque is calculated based on the linearization processing results, and the ratio of the representative values ​​between the sensors is calculated as the ratio calculation value.

6. The method according to claim 5, wherein, The threshold value is calculated by comparing the values ​​to determine the margin, and then the ratio of the representative values ​​between the sensors is calculated.

7. The method according to claim 1, wherein, The interference condition confirmation step uses the torque sensor threshold used for the torque sensor detection value and the interference driving threshold used for the ratio of representative values ​​between sensors as variables, and divides the interference driving area and the normal driving area according to the relationship between the magnitudes of the variables.

8. The method according to claim 7, wherein: The interference driving zone is defined as a situation where the torque sensor detection value is greater than the torque sensor threshold, and the ratio of the representative values ​​between the sensors is greater than the interference driving threshold. The normal driving area is the situation where the torque sensor detection value is greater than the torque sensor threshold, but the ratio of the representative values ​​between the sensors is less than the interference driving threshold.

9. The method according to claim 1, wherein, The interference-based detection is performed as follows: The interference torque threshold is applied to the torque filter value of the torque detection value, and the torque filter value is compared with the interference torque threshold. When the torque filter value is less than the interference torque threshold, the hand grip is confirmed. When the torque filter value is greater than the interference torque threshold, the system will recognize that the hand has been released.

10. The method according to claim 9, wherein, When the torque filter value is greater than the interference torque threshold, the hold-hold detection hold mode is applied to confirm the hold.

11. The method according to claim 9, wherein, The alarm light will turn on once the hand is released.

12. The method according to claim 1, wherein, The torque-based detection is performed as follows: Apply a torque threshold to the torque detection value or apply a torque change rate threshold to the torque change rate, and compare the torque detection value with the torque threshold or compare the torque change rate with the torque change rate threshold. When the torque detection value is less than the torque threshold or the torque change rate is less than the torque change rate threshold, the hand grip is confirmed. When the torque detection value is greater than the torque threshold and the torque change rate is greater than the torque change rate threshold, the hand release confirmation is detected.

13. The method according to claim 12, wherein, The alarm light will turn on once the hand is released.

14. A system for detecting when a driver's hand grips / releases its grip, comprising: A longitudinal acceleration sensor and a wheel speed sensor, wherein the longitudinal acceleration sensor and the wheel speed sensor generate sensor detection values; A torque sensor is mounted on the MDPS and detects torque values. as well as The controller is configured to: during vehicle operation and while the driver assistance system is running, calculate the ratio of the representative values ​​between the MDPS torque values ​​of the torque detection values ​​(calculated through frequency filtering) and the representative values ​​of the vehicle measurement data detected by the sensors; after confirming the torque detection values, divide the interfering driving area and the normal driving area by the magnitude of the ratio between the representative values ​​between the sensors; and execute sensor detection correction control or torque-based detection control. Sensor detection correction control identifies hand grip / release confirmation on the steering wheel by applying an interference torque threshold to the torque filter value of the torque detection values ​​in the interfering driving area, while torque-based detection control identifies hand grip / release confirmation on the steering wheel by applying upper and lower torque limit values ​​to the torque filter value of the torque detection values ​​in the normal driving area.

15. The system for detecting a driver's hand gripping / releasing as claimed in claim 14, wherein, The driving assistance system is either a lane keeping assist system that returns the vehicle to the lane when it leaves the lane, or a lane following assist system that keeps the vehicle moving along the center of the lane.

16. The system for detecting a driver's hand gripping / releasing as claimed in claim 14, wherein, The controller is connected to the warning lights and activates them when the steering wheel is released.

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