chassis control systems

Chassis Control Systems:

The chassis control system can be classified as

Brake control system Steering control system Suspension(Ride) control system Supervision Control Systems Assistance Control system

Eeshan BashirMtech ARAI Academy

BRAKE CONTROL SYSTEM:

1. ABS-Antilock Braking system: Anti-lock braking systems (ABS) are active safety features designed to help drivers retain steering control by preventing wheels from locking up during an episode of heavy braking. ABS system calculates slip ratio based on the speed of the vehicle and the wheel. That slip ratio is used to calculate the braking pressure required to avoid the wheel lock.

Sensor inputs: Wheel speed sensor Vehicle speed sensor Brake lever position sensor

The parameters that affect ABS system are:

Drive torque Wheel Mass Gravity(g) Wheel radius Moment of inertia


Braking torque

2. Traction control system: is typically a secondary function of the anti-lock braking system. TCS is activated when throttle input and engine torque are mismatched to road surface conditions causing wheel slip, designed to prevent loss of traction of driven road wheels.

Intervention consists of one or more of the following: Brake force applied to one or more wheels Reduction or suppression of spark sequence to one or more cylinders Reduction of fuel supply to one or more cylinders Closing the throttle, if the vehicle is fitted with drive by wire throttle In turbocharger vehicles, a boost control solenoid is actuated to reduce boost and

therefore engine power.


Traction Control also uses slip ratios to determine the slipping of wheels by comparing the speed of the vehicle and the wheels. The sensors are same as ABS usually TCS system comes as an advanced feature of ABS not much hardware changes are required for TCS if ABS is already there.

3. Electronic Stability Program:

This is an active safety technology that improves the stability of the vehicle by detecting and reducing loss of the traction, brakes are applied when Electronic stability program detects a loss of steering control. The loss of the steering control can be due to Under-steering or Over-steering during cornering. The ESP ECU controls against over-steering or under-steering during cornering by controlling the vehicle stability using the input values from the sensors and applying the brakes independently to the corresponding wheels. The system also limits the engine output by limiting the throttle.

Sensor Inputs: Steering wheel angle sensor Yaw rare sensor


Lateral acceleration sensor Wheel speed sensor Longitudinal acceleration sensor

Control system Diagram

These equations are used to calculate the desired values for vehicle side slip and vehicle and vehicle yaw velocity.

ESP during Under steering:

Under steering is when the steering wheel is steered to a certain angle during the front tires slip towards the reverse direction of the desired direction. The ESP system recognizes the directional angle with the steering wheel angle sensor and the slipping route that occurs reversely against the vehicle cornering direction during under-steering with the yaw rate sensor and the lateral sensor. Then the ESP system applies the brake at the rear inner wheel to compensate the yaw moment value.


ESP during Over steering:

Oversteering is when the wheel is steered to a certain angle during driving and the rear tires slip outward losing traction. ESP system recognizes the directional angle with the steering angle sensor and senses the slipping route that occurs towards the vehicle cornering direction during over steering with the yaw rate sensor and the lateral sensor. Then the ESP brakes at the front outer wheel to compensate the yaw moment value.

STEERING:

Electric Power steering


Sensors Used:o Torque sensoro Angle Sensoro Speed Sensor

Actuator Used :

o Dc Motor.

Control System:


SUSPENSION SYSTEMS:

Adaptive suspension/semi-active suspension:

The active suspension and adaptive suspension/semi-active suspension are types of automotive suspensions that control the vertical movement of the wheels with an onboard system, rather than in passive suspensions where the movement is being determined entirely by the road surface. Active suspensions can be generally divided into two main classes: pure active suspensions and adaptive/semi-active suspensions

Active suspension control system:


Sensors used:

Wheel Speed sensor Body sensors(accelerometer) Yaw rate sensors.

ASSISTANCE SYSTEMS:

Lane Assist Park Assist Adaptive Cruise Control System

Lane Assist:

Lane Assist/lane departure warning system is a mechanism designed to warn a driver when the vehicle begins to move out of its lane.

Control System:

Park Assist:


The technology assists drivers in parking their vehicle On vehicles equipped with the Park Assist system, via an in-dash screen and button controls, the car can steer itself into a parking space with little input from the user

Control System:



Adaptive cruise control system:

Adaptive cruise control (ACC) is an intelligent form of cruise control that slows down and speeds up automatically to keep pace with the car in front of you. The driver sets the maximum speed — just as with cruise control — then a radar sensor watches for traffic ahead, locks on to the car in a lane, and instructs the car to stay 2, 3, or 4 seconds behind the person car ahead of it (the driver sets the follow distance, within reason). ACC is now almost always paired with a pre-crash system that alerts you and often begins braking.

RIDE:

Tire Pressure sensor


Automotive

chassis control systems