KR20110125130A - Method for estimating friction coefficient of road surface - Google Patents

Method for estimating friction coefficient of road surface Download PDF

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KR20110125130A
KR20110125130A KR1020100044695A KR20100044695A KR20110125130A KR 20110125130 A KR20110125130 A KR 20110125130A KR 1020100044695 A KR1020100044695 A KR 1020100044695A KR 20100044695 A KR20100044695 A KR 20100044695A KR 20110125130 A KR20110125130 A KR 20110125130A
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vehicle
friction coefficient
road surface
acceleration
surface friction
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KR1020100044695A
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KR101417866B1 (en
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김중현
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주식회사 만도
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T8/00—Arrangements for adjusting wheel-braking force to meet varying vehicular or ground-surface conditions, e.g. limiting or varying distribution of braking force
    • B60T8/17—Using electrical or electronic regulation means to control braking
    • B60T8/176—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS
    • B60T8/1763—Brake regulation specially adapted to prevent excessive wheel slip during vehicle deceleration, e.g. ABS responsive to the coefficient of friction between the wheels and the ground surface
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
    • B60W40/00—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models
    • B60W40/02—Estimation or calculation of non-directly measurable driving parameters for road vehicle drive control systems not related to the control of a particular sub unit, e.g. by using mathematical models related to ambient conditions
    • B60W40/06—Road conditions
    • B60W40/068—Road friction coefficient
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60T—VEHICLE BRAKE CONTROL SYSTEMS OR PARTS THEREOF; BRAKE CONTROL SYSTEMS OR PARTS THEREOF, IN GENERAL; ARRANGEMENT OF BRAKING ELEMENTS ON VEHICLES IN GENERAL; PORTABLE DEVICES FOR PREVENTING UNWANTED MOVEMENT OF VEHICLES; VEHICLE MODIFICATIONS TO FACILITATE COOLING OF BRAKES
    • B60T2210/00—Detection or estimation of road or environment conditions; Detection or estimation of road shapes
    • B60T2210/10—Detection or estimation of road conditions
    • B60T2210/12—Friction
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60Y—INDEXING SCHEME RELATING TO ASPECTS CROSS-CUTTING VEHICLE TECHNOLOGY
    • B60Y2400/00—Special features of vehicle units
    • B60Y2400/30—Sensors
    • B60Y2400/303—Speed sensors
    • B60Y2400/3032—Wheel speed sensors

Abstract

PURPOSE: An estimating method for a surface friction coefficient is provided to improve the efficiency and stability of a TCS(traction control system) by appropriately estimating the surface friction coefficient in the acceleration using a vehicle mass, a wheel speed and an acceleration sensor signal when selecting a control parameter. CONSTITUTION: An estimating method for a surface friction coefficient comprises the following steps. A vehicle mass, a wheel speed and a vehicle acceleration are measured. The surface friction coefficient is estimated using the measured vehicle mass, wheel speed and the vehicle acceleration(118). The surface state for the TCS control is determined using the estimated surface friction coefficient. The engine torque and brake pressure are controlled. The driving power control which stably secures the acceleration performance of the vehicle is practiced.

Description

노면 마찰계수 추정방법{METHOD FOR ESTIMATING FRICTION COEFFICIENT OF ROAD SURFACE}Road surface friction coefficient estimation method {METHOD FOR ESTIMATING FRICTION COEFFICIENT OF ROAD SURFACE}

본 발명은 노면 마찰계수 추정방법에 관한 것으로, 더욱 상세하게는 차량 구동력 제어 시스템인 TCS 제어의 효율성과 안정성을 높이기 위해서 차량 가속 중 노면 마찰계수를 추정하는 방법에 관한 것이다.The present invention relates to a road surface friction coefficient estimation method, and more particularly to a method for estimating the road surface friction coefficient during vehicle acceleration in order to increase the efficiency and stability of the TCS control, a vehicle driving force control system.

차량의 엔진 성능이 고성능화되면서 차량의 주행 속도도 고속화되는 추세이다. 이에 따라 차량의 주행 안정성 향상 및 제동 안정성 확보를 위해 다양한 전자 제어 시스템이 차량에 설치된다. 이러한 차량의 전자 제어 시스템에는 차량의 제동 시 휠의 슬립에 따라 제동과 제동 해제를 반복하여 제동 안정성을 확보하는 안티록 브레이크 시스템(Anti-Lock Brake System;이하, ABS라 한다)과, 차량의 급발진 또는 급가속 시 구동륜의 슬립을 방지하는 트랙션 제어 시스템(Traction Control System;이하, TCS라 한다)과, ABS와 TCS를 조합하여 브레이크 액압을 제어함으로써 차량의 주행 안정성을 향상시키는 차량 자세 제어 시스템(Electronic Stability Program;이하, ESP라 한다) 등이 있다.As the engine performance of the vehicle is improved, the driving speed of the vehicle is also increased. Accordingly, various electronic control systems are installed in the vehicle in order to improve driving stability and ensure braking stability. The electronic control system of the vehicle includes an anti-lock brake system (hereinafter referred to as ABS) that repeatedly secures braking stability by repeatedly braking and releasing the brake according to the slip of the wheel when the vehicle is braked. Or a vehicle attitude control system that improves vehicle stability by controlling brake hydraulic pressure by combining a Traction Control System (hereinafter referred to as TCS) and ABS and TCS to prevent slippage of the driving wheel during rapid acceleration. Stability Program; hereinafter referred to as ESP).

이중에서, TCS는 차량 가속 중 과잉 구동력으로 인해 구동륜의 미끄러짐, 즉 바퀴가 헛도는 현상을 방지하여 차량의 가속성을 확보하는 차량 구동력 제어 시스템이다. 과잉 구동력 현상은 눈길이나 빙판, 젖은 노면 등 미끄러운 노면에서 발생하는데 이는 구동륜이 지지되는 노면의 마찰계수가 매우 작아 엔진 출력에 의한 구동력이 차량의 운동으로 100% 전환되지 못함에 기인한다. 따라서 TCS는 노면의 상태를 판단하여 이에 알맞게 엔진 토크 및 브레이크 압력을 제어하여 차량의 가속성을 안정적으로 확보해야 한다.Among these, the TCS is a vehicle driving force control system which secures the acceleration of the vehicle by preventing slippage of the driving wheel due to the excessive driving force during the vehicle acceleration, that is, the wheel turning off. The excessive driving force phenomenon occurs on slippery roads such as snow, ice, and wet roads, because the friction coefficient of the road on which the driving wheels are supported is very small, and the driving force due to the engine output is not 100% converted to the movement of the vehicle. Therefore, the TCS must secure the acceleration of the vehicle by judging the road condition and controlling engine torque and brake pressure accordingly.

그러나, 종래의 TCS는 차량 속도 대비 상대 슬립과 차륜 가속도를 기준으로 노면의 상태를 판단하기 때문에 판단된 노면의 마찰계수에 대한 신뢰성이 낮아 실제로 노면 마찰계수가 낮은 빙판이나 눈길 등에서는 제어 패턴이 일정하지 못하여 차량의 안정적인 구동력 제어가 원활하게 확보되지 못하는 문제점이 있다.However, since the conventional TCS determines the road surface state based on the relative slip and wheel acceleration relative to the vehicle speed, the reliability of the determined road surface friction coefficient is low, and thus the control pattern is constant on ice and snow roads having a low road surface friction coefficient. There is a problem that does not secure a stable driving force control of the vehicle smoothly.

본 발명은 차량 가속 중 노면 마찰계수를 추정하여 TCS에 제어 기준 노면 정보를 제공하며, 이를 통해 TCS 제어의 효율성과 안정성을 높이는 노면 마찰계수 추정방법을 제시하고자 한다.The present invention proposes a road surface friction coefficient estimating method for estimating road friction coefficient during vehicle acceleration and providing control reference road surface information to the TCS, thereby increasing the efficiency and stability of the TCS control.

본 발명의 일 실시예에 의한 노면 마찰계수 추정방법은, 차량 질량과 차륜속도, 차량 가속도를 측정하고; 측정된 차량 질량과 차륜속도, 차량 가속도를 이용하여 노면의 마찰계수를 추정하고; 추정된 노면의 마찰계수를 이용하여 TCS 제어를 위한 노면 상태를 판단하는 것을 특징으로 한다.Road surface friction coefficient estimation method according to an embodiment of the present invention, the vehicle mass, wheel speed, vehicle acceleration is measured; Estimating a friction coefficient of the road surface using the measured vehicle mass, wheel speed, and vehicle acceleration; The road surface state for the TCS control may be determined using the estimated coefficient of friction of the road surface.

차량 가속도를 측정하는 것은, 차량에 종가속도 센서가 장착된 경우에는 센서 신호를 필터링하여 차량 가속도로 사용하고, 차량에 종가속도 센서가 장착되지 않은 경우에는 차륜속도 중 비구동륜 속도 평균의 미분값을 취하여 차량 가속도로 사용하는 것을 특징으로 한다.To measure the vehicle acceleration, the sensor signal is used as the vehicle acceleration when the vehicle is equipped with the longitudinal acceleration sensor, and when the vehicle is not equipped with the longitudinal acceleration sensor, the derivative value of the non-drive wheel speed average among the wheel speeds is measured. It is characterized by using as a vehicle acceleration.

추정된 노면의 마찰계수는 차량 가속 시, TCS 제어의 유무와 관계없이 사용할 수 있는 것을 특징으로 한다.The estimated friction coefficient of the road surface can be used regardless of the presence or absence of TCS control during vehicle acceleration.

추정된 노면의 마찰계수는 아래의 [수학식 2]를 이용하여 계산하는 것을 특징으로 한다.The estimated friction coefficient of the road surface is characterized by using Equation 2 below.

[수학식 2][Equation 2]

μ = Μａｖ/Ν μ = Μ ａ ｖ / Ν

여기에서, μ는 노면 마찰계수이고, Ν은 수직항력이고, Μ은 차량 질량이고, ａｖ는 차량 가속도를 나타낸다.Here, μ is the road surface friction coefficient, Ν is the normal force, and Μ is vehicle mass, v represents the vehicle acceleration a.

이상에서 살펴본 바와 같이, TCS에서 노면에 맞는 제어 파라미터를 선택할 때, 차량 질량과 차륜속, 가속도 센서 신호 등을 이용하여 차량 가속 중 노면 마찰계수를 적절히 추정함으로써 TCS 제어의 효율성과 안정성을 높일 수 있게 된다.As described above, when selecting the control parameters for the road surface in the TCS, by using the vehicle mass, wheel speed, and acceleration sensor signals, the road friction coefficient during vehicle acceleration can be properly estimated to increase the efficiency and stability of the TCS control. do.

도 1은 본 발명의 일 실시예에 의한 차량 구동력 제어 시스템의 구성 블록도이다.
도 2는 본 발명의 일 실시예에 의한 차량 구동력 제어 시스템에서 노면 마찰계수를 추정하는 방법을 나타낸 동작 순서도이다.1 is a block diagram of a vehicle driving force control system according to an embodiment of the present invention.
2 is a flowchart illustrating a method of estimating a road surface friction coefficient in a vehicle driving force control system according to an embodiment of the present invention.

이하, 본 발명의 일 실시예를 첨부된 도면을 참조하여 설명한다.Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

도 1은 본 발명의 일 실시예에 의한 차량 구동력 제어 시스템의 구성 블록도이다.1 is a block diagram of a vehicle driving force control system according to an embodiment of the present invention.

도 1에서, 본 발명의 일 실시예에 의한 차량 구동력 제어 시스템은 차량 질량 측정부(10), 차륜속도 센서(20), 가속도 측정부(30), 노면 마찰계수 추정부(40), 브레이크 전자 제어 유닛(50), 엔진 제어부(620), 유압 제어부(70)를 포함한다.In FIG. 1, a vehicle driving force control system according to an exemplary embodiment of the present invention includes a vehicle mass measuring unit 10, a wheel speed sensor 20, an acceleration measuring unit 30, a road surface friction coefficient estimating unit 40, and brake electronics. The control unit 50, the engine control unit 620, the hydraulic control unit 70 is included.

차량 질량 측정부(10)는 차량의 질량(Μ)을 측정하여 노면 마찰계수 추정부(40)에 전달하는 것으로, 차량 구동력 제어 시스템에서 사용되는 각종 센서들에 의해 센싱되는 값들을 이용하여 차량의 질량(Μ)을 추정하거나, 질량 측정을 위한 질량 센서를 장착하여 차량의 질량(Μ)을 직접 측정하는 방식 등이 있다.The vehicle mass measuring unit 10 measures the mass ( M ) of the vehicle and transmits the mass to the road surface friction coefficient estimating unit 40. The vehicle mass measuring unit 10 measures the mass of the vehicle using values sensed by various sensors used in the vehicle driving force control system. There is a method of estimating mass ( M ) or directly measuring the mass ( M ) of a vehicle by installing a mass sensor for mass measurement.

차륜속도 센서(20)는 차량의 전륜(FL, FR)과 후륜(RL, RR)의 네 바퀴에 각각 설치되어 각 차륜(FL, FR, RL, RR)의 속도를 검출하여 노면 마찰계수 추정부(40)에 전달한다.The wheel speed sensor 20 is installed on four wheels of the front wheels FL and FR and rear wheels RL and RR of the vehicle, respectively, and detects the speed of each wheel FL, FR, RL and RR to detect the road surface friction coefficient. Pass in 40.

가속도 측정부(30)는 차량의 가속도(ａｖ)를 측정하여 노면 마찰계수 추정부(40)에 전달하는 것으로, 차량의 가속도(ａｖ)는 차량의 구동력, 즉 엔진 출력에 의한 차량 운동의 결과로 나타나는 물리량을 의미한다. 종가속도 센서가 장착된 경우에는 종가속도 센서 신호를 단순 필터링하여 차량 가속도를 측정하고, 종가속도 센서가 장착되지 않은 경우에는 차륜속도 중 비구동륜의 속도 평균의 미분값을 사용하여 차량 가속도를 측정한다.Acceleration measurement unit 30 of the vehicle movement due to that by measuring the acceleration (a v) of the vehicle transmitted to the road surface friction coefficient estimation unit 40, the acceleration of the vehicle (a v) is the driving force of the vehicle, i.e. the engine power It means the resultant physical quantity. When the longitudinal acceleration sensor is installed, the vehicle acceleration is measured by simply filtering the longitudinal acceleration sensor signal, and when the longitudinal acceleration sensor is not equipped, the vehicle acceleration is measured by using the derivative value of the speed average of the non-drive wheel among the wheel speeds. .

노면 마찰계수 추정부(40)는 차량 질량 측정부(10)에 의해 측정된 차량 질량(Μ)과, 차륜속도 센서(20)에 의해 검출된 차륜속도, 가속도 측정부(30)에 의해 측정된 차량의 가속도(ａｖ)를 이용하여 차량의 가속 중 노면의 마찰계수(μ)를 추정한다. 노면의 마찰계수(μ)를 추정하는 것은 수평의 지면에 네 바퀴(FL, FR, RL, RR)로 지지된 차량에 구동력이 인가되고, 이로부터 차량의 운동이 발생할 때 노면 마찰력과 차량 운동력 간의 힘의 균형을 반영하는 아래의 [수학식 1]과 같은 간단한 물리식으로 출발한다.The road surface friction coefficient estimator 40 measures the vehicle mass Μ measured by the vehicle mass measuring unit 10 and the wheel speed and acceleration measurement unit 30 detected by the wheel speed sensor 20. to estimate the friction coefficient (μ) of the road surface during acceleration of the vehicle using the acceleration of the vehicle (a v). Estimating the friction coefficient ( μ ) of the road surface is applied to the vehicle supported by four wheels (FL, FR, RL, RR) on the horizontal ground, and when the vehicle motion occurs, Start with a simple physics equation like Equation 1 below that reflects the balance of power.

[수학식 1][Equation 1]

μΝ = Μａｖ μΝ = Μ ａ ｖ

여기에서, μ는 노면 마찰계수이고, Ν은 수직항력이고, Μ은 차량 질량이고, ａｖ는 차량 가속도를 나타낸다.Here, μ is the road surface friction coefficient, Ν is the normal force, and Μ is vehicle mass, v represents the vehicle acceleration a.

따라서, 추정하고자 하는 노면 마찰계수(μ)는 아래의 [수학식 2]을 이용하여 계산할 수 있다.Therefore, the road friction coefficient ( μ ) to be estimated can be calculated using Equation 2 below.

[수학식 2][Equation 2]

μ = Μａｖ/Ν μ = Μ ａ ｖ / Ν

이때, 수직항력(Ν)은 구동 방식에 따라 달라진다. 2륜 구동(2WD)의 경우, 차량의 전륜(FL, FR)과 후륜(RL, RR) 중 한 쌍의 바퀴{(FL, FR) 또는 (RL, RR)}에 전달되는 구동륜에 지지되는 수직항력(Ν)만이 해당하므로 사전에 차량 질량(Μ)을 부분별로 측정하여 해당 질량(Μ)에 중력가속도를 곱하여 계산한다. 4륜 구동(4WD)의 경우, 네 바퀴(FL, FR, RL, RR) 모두 구동륜이 되므로 단순히 차량 질량(Μ)과 중력가속도의 곱으로 수직항력(Ν)을 계산한다.At this time, the vertical drag Ν depends on the driving method. In the case of the two-wheel drive 2WD, a vertical support supported by the drive wheels transmitted to the pair of wheels ((FL, FR) or (RL, RR)) of the front wheels FL and FR of the vehicle and the rear wheels RL and RR. Since only drag ( Ν ) is applicable, the vehicle mass ( Μ ) is measured in parts and calculated by multiplying the mass ( Μ ) by the gravitational acceleration. In the case of four-wheel drive (4WD), since all four wheels (FL, FR, RL, RR) are driving wheels, the vertical drag ( Ν ) is calculated simply by the product of the vehicle mass ( Μ ) and the acceleration of gravity.

브레이크 전자 제어 유닛(50)은 노면 마찰계수 추정부(40)에 의해 추정된 노면 마찰계수(μ)의 정보를 바탕으로 엔진 토크와 브레이크 압력 제어 파라미터를 구성하여 각 차륜(FL, FR, RL, RR)의 브레이크 압력과 엔진 토크를 제어하기 위한 신호를 엔진 제어부(60)와 유압 제어부(70)에 출력한다.Brake electronic control unit 50 for each wheel by constructing a road surface friction coefficient (μ) of the information based on the engine torque and the brake pressure control parameters estimated by the road surface friction coefficient estimation section (40) (FL, FR, RL, Signals for controlling the brake pressure and engine torque of the RR are output to the engine control unit 60 and the hydraulic control unit 70.

엔진 제어부(60)는 브레이크 전자 제어 유닛(50)으로부터 출력되는 엔진 제어 신호에 따라 엔진 토크를 제어하여 차량의 안정성을 최대한 확보하도록 TCS 제어블록(61)과 협조 제어하여 차량의 가속 중 엔진의 구동력을 제어한다.The engine controller 60 controls the engine torque according to the engine control signal output from the brake electronic control unit 50 to cooperatively control the engine control force with the TCS control block 61 so as to secure the stability of the vehicle. To control.

유압 제어부(70)는 브레이크 전자 제어 유닛(50)으로부터 출력되는 브레이크 제어 신호에 따라 각 차륜(FL, FR, RL, RR)의 휠 실린더에 공급되는 브레이크 액압을 제어하여 차량의 안정성을 최대한 확보하도록 브레이크 압력을 발생한다.The hydraulic control unit 70 controls the brake hydraulic pressure supplied to the wheel cylinders of the wheels FL, FR, RL, and RR according to the brake control signal output from the brake electronic control unit 50 so as to ensure the stability of the vehicle to the maximum. Generate brake pressure.

이하, 상기와 같이 구성된 차량 구동력 제어 시스템에서 노면의 마찰계수를 추정하는 방법의 동작과정 및 작용효과를 설명한다.Hereinafter, an operation process and an effect of the method for estimating the friction coefficient of the road surface in the vehicle driving force control system configured as described above will be described.

도 2는 본 발명의 일 실시예에 의한 차량 구동력 제어 시스템에서 노면 마찰계수를 추정하는 방법을 나타낸 동작 순서도이다.2 is a flowchart illustrating a method of estimating a road surface friction coefficient in a vehicle driving force control system according to an embodiment of the present invention.

도 2에서, 차량에 종가속도 센서가 장착되었는가를 판단하여(100), 차량에 종가속도 센서가 장착된 경우 종가속도 센서가 정상 동작하는가를 판단한다(102).In FIG. 2, it is determined whether the longitudinal acceleration sensor is mounted on the vehicle (100), and when the longitudinal acceleration sensor is mounted on the vehicle, it is determined whether the longitudinal acceleration sensor operates normally (102).

단계 102의 판단 결과, 종가속도 센서가 정상 동작하는 경우, 가속도 측정부(30)는 종가속도 센서에서 검출된 신호를 단순 필터링하여 차량의 가속도(ａｖ)로 측정하고, 이를 노면 마찰계수 추정부(40)에 전달한다(104).If it is determined in step 102, the closing velocity sensor for normal operation, the acceleration measuring section 30 is closing speed filters simple a signal detected by the sensor is measured by the acceleration of the vehicle (a v), this road surface friction coefficient estimation unit (104).

한편, 단계 100의 판단 결과, 차량에 종가속도 센서가 장착되지 않은 경우, 가속도 측정부(30)는 차륜속도 센서(20)에서 검출된 차륜속도 중 비구동륜 속도를 평균한 속도 평균의 미분값을 취하여 차량의 가속도(ａｖ)로 측정하고, 이를 노면 마찰계수 추정부(40)에 전달한다(106).On the other hand, as a result of the determination in step 100, when the vehicle is not equipped with a longitudinal acceleration sensor, the acceleration measuring unit 30 is a derivative of the average of the speed averaged average of the non-drive wheel speed of the wheel speed detected by the wheel speed sensor 20 Taken and measured by the acceleration (a ｖ ) of the vehicle, and transmits it to the road surface friction coefficient estimator 40 (106).

이후, 차량의 구동 방식이 4륜 구동(4WD)인가를 판단하여(108), 차량의 구동 방식이 4륜 구동(4WD)인 경우 차량의 네 바퀴(FL, FR, RL, RR)가 모두 구동륜이 되므로 노면 마찰계수 추정부(40)는 단순히 차량 질량(Μ)과 중력가속도의 곱으로 전륜(FL, FR)과 후륜(RL, RR) 전체의 수직항력(Ν)을 계산한다(110).Then, it is determined whether the driving method of the vehicle is the four-wheel drive (4WD) (108), and if the driving method of the vehicle is the four-wheel drive (4WD), all four wheels (FL, FR, RL, RR) of the vehicle are driving wheels. Therefore, the road surface friction coefficient estimating unit 40 calculates the vertical drag ( N ) of the entire front wheels FL and FR and the rear wheels RL and RR simply by multiplying the vehicle mass Μ by the gravity acceleration 110.

단계 108의 판단 결과, 차량의 구동 방식이 4륜 구동(4WD)이 아닌 경우에는 2륜 구동(2WD)이라고 판단하여 차량의 구동 방식이 전륜(FL, FR) 구동인가를 판단한다(112).As a result of the determination in step 108, if the driving method of the vehicle is not the four-wheel drive (4WD), it is determined that the two-wheel drive (2WD) to determine whether the driving method of the vehicle is driving the front wheels (FL, FR) (112).

단계 112의 판단 결과, 차량의 구동 방식이 전륜(FL, FR) 구동인 경우, 차량의 전륜(FL, FR)이 구동륜이 되므로 노면 마찰계수 추정부(40)는 사전에 부분별로 측정된 차량 질량(Μ)에 중력가속도를 곱하여 전륜(FL, FR)의 수직항력(Ν)만을 계산한다(114).As a result of the determination in step 112, when the driving method of the vehicle is the front wheels FL and FR, the front wheels FL and FR of the vehicle become the driving wheels, so that the road surface friction coefficient estimator 40 measures the vehicle mass previously measured for each part. Multiply ( M ) by the acceleration of gravity to calculate only the normal drag ( N ) of the front wheels (FL, FR) (114).

한편, 단계 112의 판단 결과, 차량의 구동 방식이 전륜(FL, FR) 구동이 아닌 경우, 차량의 후륜(RL, RR)이 구동륜이 되므로 노면 마찰계수 추정부(40)는 사전에 부분별로 측정된 차량 질량(Μ)에 중력가속도를 곱하여 후륜(RL, RR)의 수직항력(Ν)만을 계산한다(116).On the other hand, as a result of the determination in step 112, when the vehicle driving method is not driving the front wheels (FL, FR), the rear wheels (RL, RR) of the vehicle is a driving wheel, so the road surface friction coefficient estimator 40 previously measured for each part Only the normal drag ( N ) of the rear wheels (RL, RR) is calculated by multiplying the calculated vehicle mass ( Μ ) by gravity acceleration (116).

따라서, 노면 마찰계수 추정부(40)는 차량 질량(Μ)과 차량 가속도(ａｖ), 수직항력(Ν)을 이용하여 아래의 [수학식 2]에 따라 노면 마찰계수(μ)를 추정한다.Accordingly, the road surface friction coefficient estimator 40 estimates the road surface friction coefficient μ using Equation 2 below by using the vehicle mass ( M ), the vehicle acceleration (A ｖ ), and the vertical drag ( N ). .

[수학식 2][Equation 2]

μ = Μａｖ/Ν μ = Μ ａ ｖ / Ν

여기에서, μ는 노면 마찰계수이고, Ν은 수직항력이고, Μ은 차량 질량이고, ａｖ는 차량 가속도를 나타낸다.Here, μ is the road surface friction coefficient, Ν is the normal force, and Μ is vehicle mass, v represents the vehicle acceleration a.

이에 따라, 브레이크 전자 제어 유닛(50)은 노면 마찰계수 추정부(40)에서 추정된 노면 마찰계수(μ)의 정보를 바탕으로 엔진 토크 및 브레이크 압력 제어 파라미터를 구성하여 차량의 가속 중 구동력 제어에 이용함으로써 보다 효율적이고 안정적인 TCS 제어를 행할 수 있도록 한다(120).Accordingly, the brake electronic control unit 50 for accelerating the driving force control of the vehicle by configuring the engine torque and the brake pressure control parameters based on information from the road surface friction coefficient (μ) estimate from the road surface friction coefficient estimation unit 40, By using this method, more efficient and stable TCS control can be performed (120).

10 : 차량 질량 측정부 20 : 차륜속도 센서
30 : 가속도 측정부 40 : 노면 마찰계수 추정부
50 : 브레이크 전자 제어 유닛 60 : 엔진 제어부
70 : 유압 제어부10: vehicle mass measurement unit 20: wheel speed sensor
30: acceleration measurement unit 40: road surface friction coefficient estimation unit
50: brake electronic control unit 60: engine control unit
70: hydraulic control unit

Claims (4)

차량 질량과 차륜속도, 차량 가속도를 측정하고;
상기 측정된 차량 질량과 차륜속도, 차량 가속도를 이용하여 노면의 마찰계수를 추정하고;
상기 추정된 노면의 마찰계수를 이용하여 TCS 제어를 위한 노면 상태를 판단하는 노면 마찰계수 추정방법.Measure vehicle mass, wheel speed, vehicle acceleration;
Estimating a friction coefficient of a road surface using the measured vehicle mass, wheel speed, and vehicle acceleration;
Road surface friction coefficient estimation method for determining the road surface state for the TCS control using the estimated friction coefficient of the road surface. 제1항에 있어서,
상기 차량 가속도를 측정하는 것은,
상기 차량에 종가속도 센서가 장착된 경우에는 센서 신호를 필터링하여 차량 가속도로 사용하고,
상기 차량에 종가속도 센서가 장착되지 않은 경우에는 상기 차륜속도 중 비구동륜 속도 평균의 미분값을 취하여 차량 가속도로 사용하는 노면 마찰계수 추정방법.The method of claim 1,
Measuring the vehicle acceleration,
When the longitudinal acceleration sensor is mounted on the vehicle, the sensor signal is filtered and used as the vehicle acceleration.
If the vehicle is not equipped with a longitudinal acceleration sensor, the road friction coefficient estimation method for taking the derivative of the average of the non-drive wheel speed of the wheel speed to use as the vehicle acceleration. 제1항에 있어서,
상기 추정된 노면의 마찰계수는 차량 가속 시, TCS 제어의 유무와 관계없이 사용할 수 있는 노면 마찰계수 추정방법.The method of claim 1,
And the estimated friction coefficient of the road surface may be used regardless of the presence or absence of TCS control during vehicle acceleration. 제1항에 있어서,
상기 추정된 노면의 마찰계수는 아래의 [수학식 2]를 이용하여 계산하는 노면 마찰계수 추정방법.
[수학식 2]
μ = Μａｖ/Ν
여기에서, μ는 노면 마찰계수이고, Ν은 수직항력이고, Μ은 차량 질량이고, ａｖ는 차량 가속도를 나타낸다.The method of claim 1,
The estimated friction coefficient of the road surface is calculated using the equation [2] below.
[Equation 2]
μ = Μ ａ ｖ / Ν
Here, μ is the road surface friction coefficient, Ν is the normal force, and Μ is vehicle mass, v represents the vehicle acceleration a.
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KR20150006592A (en) * 2013-07-09 2015-01-19 삼성전자주식회사 Mobile robot having function estimating friction coefficient and method of estimating the same
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