汽车电子控制技术(Bilingual 12.14)
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18
2012/12/22
In order to determine the desired performance, the signals are evaluated which define the driver's input.
These comprise the signals from the steering-wheel sensor (3, driver's steering input), the brake-pressure sensor (2, desired deceleration input), and the engine management (7, desired drive torque).
2012/12/22
19
Apart from the vehicle speed, the calculation of the desired performance also takes the coefficients of adhesion between the tires and the road into account. These are calculated from the signals outputted by the wheel-speed sensors (1), the lateral-acceleration sensor (5), the yaw-rate sensor (4), and the brake-pressure sensor (2).
20wk.baidu.com2/12/22
10
Lateral dynamics of a vehicle 1. Step input at steering wheel, steering- wheel angle fixed; 2. Track on highμroad; 3. Track on lowμroad with "open-loop" steering correction and yaw-rate control; 4. Track on low- μ road when the slip angle is also controlled (ESP);
⑷ Improved handling behavior also in limit situations. For the driver, this behavior becomes predictable as a function of his (or her) experience. The vehicle remain fully under control even in critical traffic situations;
2012/12/22
2
8.5 The ABS functions expand 8.5.1 The ASR system 8.5.2 The ESP system
2012/12/22
3
8.5.2 The ESP system 1. The basic function of the ESP; 2. Vehicle handling characteristic introduction. 3. ESP control systems
2012/12/22
8
2. Vehicle handling The vehicle's steering properties are defined in the description of the vehicle's lateral dynamics. This description is derived from steadystate cornering and shows the dependence of the tire slip angle a on the lateral vehicle acceleration ay and therefore on the lateral tire forces on the tire slip.
2012/12/22
5
Further to the advantages inherent in ABS and ASR, ESP improves the active driving safety in the following points:
⑴ Provides the driver with active support, even in laterally critical dynamic; ⑵ Enhances vehicle stability and tracking performance even in limit situations in all operating modes such as full braking, partial braking, coasting, accelerating, engine drag, and load shift;
2012/12/22
9
Lateral dynamics of a vehicle 1. Step input at steering wheel, steering- wheel angle fixed; 2. Track on highμroad; 3. Track on lowμroad with "openloop" steering correction and yawrate control; 4. Track on low- μ road when the slip angle is also controlled (ESP);
2012/12/22
14
The overall system (see Fig.), shows the vehicle as the controlled system, with Sensors (1...5) for defining the controller input variables, and actuators (6 and 7) for influencing the tractive force and the braking force. Also shown are the hierarchically structured controller comprising the higherlevel vehicle dynamics controller, and the lower-level slip controllers.
2012/12/22
7
⑸ Depending upon the situation, even better utilization of the adhesion potential between the tires and the road when ABS and TCS intervene, and therefore improved traction and stopping distances in addition to improved steerability and stability.
The automoive electronics control technique
Southeast University Mechanical Department
Feng Chong-Yi
2012/12/22
1
Previous lessen content review lessen (12/03/2012): The 8th chapter: The brake system 8.1 brief introduction of the Brake system 8.2 Anti-lock Brake System (ABS) 8.3 Criteria of control quality 8.4 ABS Versions 8.5 The ABS functions expand The contents for today (12/06/2012)
2012/12/22
16
Observer Estimated value of vehicle-motion variables ESPcontroller Sideslip- angle control and yaw- rate control
Slip controller with intorface to ESP
2012/12/22
6
⑶ Enhances directional stability even during extreme steering maneuvers (panic reactions), resulting in a drastic reduction in the danger of skidding;
2012/12/22 15
The higher-level controllers input the nominal values to the lower-level controllers in the form of a nominal slip. The "observer" determines the controlled state variable (vehicle slip angle β).
2012/12/22
12
Block diagram of ESP controller
2012/12/22 13
In this respect, as shown in the block diagram, it must first of all be defined how the vehicle is to behave at the physical driving limit in accordance with the driver's input (nominal behavior), and how it actually behaves (actual behavior). In order to minimize the difference between nominal and actual behavior (deviation), the tire forces must in some way be controlled by actuators.
2012/12/22
17
Overall control system of ESP
1. 2. 3. 4. 5. 6. 7. 8. Wheel-speed sensors; Brake-pressure sensor; Steering-wheel sensor; Yaw-rate sensor; Lateral-acceleration sensor; Pressure modulation; Engine management; Sensor signals for ESP: α Tire slip angle, δW Steering angle of the wheel, λNo Nominal tire slip.
2012/12/22
11
3. ESP control systems ⑴ control The control of the vehicle's behavior at the physical driving limit must influence the vehicle's three degrees of freedom in the plane of the road (longitudinal and lateral velocities, and yaw moment about the vertical axis) so that vehicle handling is in line with the driver's input and with the prevailing road conditions.
brief
2012/12/22
4
1. The basic function of the ESP While ABS prevents wheel lockup when braking and ASR (TCS) prevents spin of the driven wheels, ESP prevents the vehicle from "pushing out" of the turn or spinning out of the turn when it is steered.
2012/12/22
In order to determine the desired performance, the signals are evaluated which define the driver's input.
These comprise the signals from the steering-wheel sensor (3, driver's steering input), the brake-pressure sensor (2, desired deceleration input), and the engine management (7, desired drive torque).
2012/12/22
19
Apart from the vehicle speed, the calculation of the desired performance also takes the coefficients of adhesion between the tires and the road into account. These are calculated from the signals outputted by the wheel-speed sensors (1), the lateral-acceleration sensor (5), the yaw-rate sensor (4), and the brake-pressure sensor (2).
20wk.baidu.com2/12/22
10
Lateral dynamics of a vehicle 1. Step input at steering wheel, steering- wheel angle fixed; 2. Track on highμroad; 3. Track on lowμroad with "open-loop" steering correction and yaw-rate control; 4. Track on low- μ road when the slip angle is also controlled (ESP);
⑷ Improved handling behavior also in limit situations. For the driver, this behavior becomes predictable as a function of his (or her) experience. The vehicle remain fully under control even in critical traffic situations;
2012/12/22
2
8.5 The ABS functions expand 8.5.1 The ASR system 8.5.2 The ESP system
2012/12/22
3
8.5.2 The ESP system 1. The basic function of the ESP; 2. Vehicle handling characteristic introduction. 3. ESP control systems
2012/12/22
8
2. Vehicle handling The vehicle's steering properties are defined in the description of the vehicle's lateral dynamics. This description is derived from steadystate cornering and shows the dependence of the tire slip angle a on the lateral vehicle acceleration ay and therefore on the lateral tire forces on the tire slip.
2012/12/22
5
Further to the advantages inherent in ABS and ASR, ESP improves the active driving safety in the following points:
⑴ Provides the driver with active support, even in laterally critical dynamic; ⑵ Enhances vehicle stability and tracking performance even in limit situations in all operating modes such as full braking, partial braking, coasting, accelerating, engine drag, and load shift;
2012/12/22
9
Lateral dynamics of a vehicle 1. Step input at steering wheel, steering- wheel angle fixed; 2. Track on highμroad; 3. Track on lowμroad with "openloop" steering correction and yawrate control; 4. Track on low- μ road when the slip angle is also controlled (ESP);
2012/12/22
14
The overall system (see Fig.), shows the vehicle as the controlled system, with Sensors (1...5) for defining the controller input variables, and actuators (6 and 7) for influencing the tractive force and the braking force. Also shown are the hierarchically structured controller comprising the higherlevel vehicle dynamics controller, and the lower-level slip controllers.
2012/12/22
7
⑸ Depending upon the situation, even better utilization of the adhesion potential between the tires and the road when ABS and TCS intervene, and therefore improved traction and stopping distances in addition to improved steerability and stability.
The automoive electronics control technique
Southeast University Mechanical Department
Feng Chong-Yi
2012/12/22
1
Previous lessen content review lessen (12/03/2012): The 8th chapter: The brake system 8.1 brief introduction of the Brake system 8.2 Anti-lock Brake System (ABS) 8.3 Criteria of control quality 8.4 ABS Versions 8.5 The ABS functions expand The contents for today (12/06/2012)
2012/12/22
16
Observer Estimated value of vehicle-motion variables ESPcontroller Sideslip- angle control and yaw- rate control
Slip controller with intorface to ESP
2012/12/22
6
⑶ Enhances directional stability even during extreme steering maneuvers (panic reactions), resulting in a drastic reduction in the danger of skidding;
2012/12/22 15
The higher-level controllers input the nominal values to the lower-level controllers in the form of a nominal slip. The "observer" determines the controlled state variable (vehicle slip angle β).
2012/12/22
12
Block diagram of ESP controller
2012/12/22 13
In this respect, as shown in the block diagram, it must first of all be defined how the vehicle is to behave at the physical driving limit in accordance with the driver's input (nominal behavior), and how it actually behaves (actual behavior). In order to minimize the difference between nominal and actual behavior (deviation), the tire forces must in some way be controlled by actuators.
2012/12/22
17
Overall control system of ESP
1. 2. 3. 4. 5. 6. 7. 8. Wheel-speed sensors; Brake-pressure sensor; Steering-wheel sensor; Yaw-rate sensor; Lateral-acceleration sensor; Pressure modulation; Engine management; Sensor signals for ESP: α Tire slip angle, δW Steering angle of the wheel, λNo Nominal tire slip.
2012/12/22
11
3. ESP control systems ⑴ control The control of the vehicle's behavior at the physical driving limit must influence the vehicle's three degrees of freedom in the plane of the road (longitudinal and lateral velocities, and yaw moment about the vertical axis) so that vehicle handling is in line with the driver's input and with the prevailing road conditions.
brief
2012/12/22
4
1. The basic function of the ESP While ABS prevents wheel lockup when braking and ASR (TCS) prevents spin of the driven wheels, ESP prevents the vehicle from "pushing out" of the turn or spinning out of the turn when it is steered.