It’s no great revelation that cars have come a long way since the early days of steam propulsion. And while we still haven’t quite met the predictions of 80s sci-fi automotive transportation, we’re certainly on our way.
It is now nearly 350 years since Belgian mathematician and astronomer Ferdinand Verbiest showcased the first automobile to the world. In that time, cars have become safer, easier to control, and more comfortable for drivers.
Embedded systems have played their part in this evolution of the automobile.
Embedded software supports most car features using Electronic Control Units (ECUs). A high-end vehicle may have over 100 ECUs communicating using 3000-5000 signals. Those ECUs use various microcontrollers, microprocessors, and Field Programmable Gate Array (FPGA) support.
It’s safe to say that embedded systems play an integral role in the safety and comfort we enjoy while driving modern cars. But what exactly are they? This article explores the central embedded systems used in cars today.
1. Anti-Lock Braking System (ABS)
ABS prevents wheels from locking up during the braking process. This is particularly useful on slippery surfaces. The primary components of the ABS include:
- Electronic Control Unit: ECU uses data from sensors to figure out whether to pump the brakes.
- Hydraulic Control Unit: The hydraulic control unit holds pumps filled with hydraulic fluid. The pumps apply pressure to the brake drums when there is a need to do so.
- Valves: Brakes positioned in the brake line regulate pressure, allowing or blocking the pressure applied on the brakes.
- Wheel sensor unit: These sensors check how fast the car wheels are running.
Sensors are attached to wheels to detect locking or when the wheel stops moving and begins to skid off the ground.
First, the working stages of ABS involve the driver pushing the brake pedal. Wheel sensors then detect skidding or locking, and subsequently, the ABS pumps the brakes.
ABS provides traction control by rhythmically restoring grip to wheels that slip off the ground by applying the brake.
(ABS is a precursor to today’s drive-by-wire systems, and you’ll find more on those further down.)
2. Electronic Stability Control (ESC)
The ESC system increases the car’s stability on the road. It works with the Anti-Lock Braking System (ABS) to avoid understeer or oversteer situations that might cause skidding.
Understeer is when the vehicle loses front-wheel traction and wants to push forward nose-first. Oversteer is when the rear wheels lose traction, and the back begins to slide.
This system is beneficial when the driver somehow loses control of the steering wheel. It automatically applies brakes to have the car move in the intended direction. Braking is applied to the different wheels. The system works with the ABS by enabling the ESC to slow down the wheels.
Sensors used in this system include:
- Steering wheel angle sensor
- Wheel speed sensors
- Lateral sensor
- A yaw rate sensor
3. Adaptive Cruise Control System
The Adaptive Cruise Control System controls the car’s speed by adjusting the throttle position. It uses sensors to tell the speed and throttle position.
This system helps the driver to drive safely on the road in traffic. For example, it allows the driver to cruise at a given speed when the road is clear (cruise control). Adaptive means the car monitors the speed of the vehicle in front and adapts the set speed to track a vehicle in front.
Drive-by-wire technology replaces or augments traditional mechanical control systems that use hydraulics or cables with electronic control systems. These systems use sensors and actuators to control elements of vehicle operation. They can also enable non-traditional human-machine interfaces such as controls like joysticks or paddles. Drive-by-Wire covers three central systems:
- Steer-by-wire: no physical connection between a steering wheel and tyres.
- Electronic throttle control: no physical connection between accelerator pedal and throttle.
- Brake-by-wire: in an actual electromechanical version of this, there is no hydraulic part, but instead, sensors determine how much force is used.
Steer-by-wire and brake-by-wire are not as widely used (yet), but electronic throttle control has been present in vehicles for some time. A low-level of electronic throttle control has been used for decades in cars that have computerised fuel controls.
Currently, Tesla is one of the few car brands on the road that have extensively used all types of drive-by-wire systems.
5. Airbag Control Unit
The airbag control unit protects the front passengers from head collisions in the case of an accident.
Depending on the severity of an accident, the system triggers the right restraint systems. Crash sensors send information to the micro-controllers to release the airbags. These sensors detect speed and rotational speed.
The airbag control unit stores crash data that explains the events leading up to the occurrence of the accident.
The collected data is beneficial during investigations of the causes of an accident. For example, information collected can include the speed at which the car was moving.
6. Telematics System
Telematics brings several features to a vehicle. First, it controls wireless tracking and contact to and from the car.
Telematics allows cars to communicate with other devices via an internet connection. Vehicles with embedded telematics systems send the vehicle’s data to the producer for regulation.
Recorded information includes the car’s location, tyre pressure, fuel tank level, and engine oil life. This all guides the producer in making servicing instructions.
7. Rain-Sensing System
The rain-sensing system uses infrared light as the primary signal to trigger the wipers.
An optical sensor is placed on the front windshield glass to emit infrared light. Depending on the amount of reflected light, the optical sensor decides the speed of the windshield wipers.
8. Automotive Night Vision System
This system creates enhanced night vision for the driver to provide better visibility at night.
The light generated goes beyond the reach of the headlights. The system detects pedestrians or obstacles near the road and highlights any hazards that may be hazardous.
Night Vision Devices (NVD) like infrared cameras and Radar devices support Night Vision Systems. These devices work in image enhancement, thermal imaging, and active lighting modes. These systems fall either in the Active or Passive categories.
Dynamic systems use infrared light sources to light a long distance ahead of the car headlamps. Rolls-Royce Motor Cars and Toyota are some brands that have installed these systems in their vehicles.
The passive systems run differently. They use cameras to capture thermal radiation emitted by surrounding objects. Some car brands using passive night vision systems include Cadillac, BMW, and Audi.
9. Climate Control System
Cars need to be prepared for all types of weather. Maintaining a comfortable cabin environment is essential for the driver and the passengers.
The climate control system embedded in a car regulates the vehicle’s internal temperature. Maintaining a proper climate in the car does factor into automotive safety.
10. Blind-Spot Monitoring System
The blind-spot monitoring system helps increase safety by alerting the driver. Often vehicles will be out of the driver’s field of vision in the side-view mirrors.
This system uses radar sensors found inside the left and right sides of the rear bumpers. It uses cameras in the side-view mirrors to find vehicles in their view.
Blind spots are more likely to be an issue when a driver tries to change lanes or park.
The Future of embedded systems in cars
Embedded systems are not simply used in high-end vehicles to power luxury accessories. (Although they do that too!)
They are crucial to the performance and safety of all modern cars. And they will continue to play a vital role in the evolution of automobiles as electric, and hydrogen vehicles become commonplace and research into self-driving vehicles expands.
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