The World’s Smallest and Lightest ABS Develop a Brake System of Outstanding Performance Second to None The World’s Smallest and Lightest ABS Develop a Brake System of Outstanding Performance Second to None

The Spirit of Monozukuri—5 The Spirit of Monozukuri—5
The Story Behind the Development of the Anti-lock Braking System The Story Behind the Development of the Anti-lock Braking System
the Anti-lock Braking System

ABS—Anti-lock Braking System Designed for Helping Vehicles Come to a Safe Stop ABS—Anti-lock Braking System Designed for Helping Vehicles Come to a Safe Stop

Among the primary dynamic factors of a vehicle, turning and braking are those critical to determining the performance of the vehicle and safe driving.
Ever lost the control with the wheels locked after sudden braking your car on an icy or wet road?
Skidding on an icy or wet road increases the risk of a crash.

When driving in slippery conditions, the anti-lock braking system (ABS) is a major safety feature because it prevents the wheels from locking up.

On a car fitted with an ABS, the electronics are performing cadence braking to prevent wheel locking when the driver suddenly pumps the brake pedal.
This allows the driver to come to a safe stop.

Anti-lock Braking System (ABS)

A safety system that operates by preventing the wheels from locking up or the vehicle from slipping during braking.
Effective when driving in slippery conditions, e.g., wet or icy roads.

Anti-lock Braking System (ABS) Anti-lock Braking System (ABS)

A Wave of Trend Changes Shock ABS Manufacturers in the Battle for Market Dominance A Wave of Trend Changes Shock ABS Manufacturers in the Battle for Market Dominance

Aisin Seiki began development on ABSs back in the 1970s.
Work started with a pneumatic ABS and was followed by a hydraulic ABS in the 1980s, then shifted to the ECU-controlled four-wheel ABS, which is the mainstream in ABSs today. Aisin's ABSs have been in use on vehicles from Toyota Motor Corporation and other Japanese automobile manufacturers.

The early electronic ABS units were designed as add-on systems. But, demand for ABSs surged as needs for cars with more safety features spurred auto manufacturers to fit more vehicles with ABSs as a standard feature.
Auto component suppliers competed fiercely for market share.
In the battle for market dominance, ABS manufacturers released new models every two years from the late 1980s through to the mid-1990s.
Then, between 1993 and 1994, a wave of trend changes shook the industry.

Toyota Motor announced that they were making it mandatory for all new model vehicles to have ABS as a standard.
That meant shorter cycle times for product development and more competition in pricing.

Profit, for any business, is the primary goal, but how to make ends meet is always a question.
Every ABS manufacturer seemed to have limited options.

ABS—Components and How It Works

The rotational speed of each wheel is monitored by speed sensors, and when slipping is detected, the ECU signals the hydraulic unit to control pressure to prevent wheel lock-up.

ABS—Components and How It Works ABS—Components and How It Works

“Reduce Dimensions, Weight, Cost, Everything to Half.” “Reduce Dimensions, Weight, Cost, Everything to Half.”

The first move came quickly from Aisin's Drivetrain Engineering.

“It's not bad luck. It's an opportunity to do good business.”
“One thing for sure is that there will be more severe price competition.”
“Definitely, the market demand will grow. We can't sit and wait.”
“We have technologies right here and now that which help us produce an ABS that outperforms competitor products.”

The goal was set—“Build the world's most compact, lightest, and best ECU-controlled ABS, at lower cost.”

All target figures for dimensions, weight, and cost per unit were set one half those of existing products.
Achieving the goal would increase global presence and show Aisin's initiative and competitiveness in the market.

Across divisions, the project members shared one watchword— “Reduce everything in half.”

Needed were technologies that existed nowhere back then. It was not, in many ways, an easy task to commercialize a product that would require the introduction of new ideas, methods, and more.
The product being developed was given a code name -- “A21V (Afterward changed to GA21)” -- representing the resolution everyone had: “What we are aiming at is a signature product of the Aisin brand that will bring victory in the 21st century.”

In November 1996, the project officially began.

How an ABS Works

The rotational speed of each wheel is monitored by speed sensors, and when slipping is detected, the ECU signals the hydraulic unit to control pressure to prevent wheel lock-up.

Required is the Smartest ECU in the Size of a Business Card. Required is the Smartest ECU in the Size of a Business Card.

The predecessor code-modeled AIV was 2 L in volume and 3 kg in weight.
Reducing it to half means making an ABS module with a volume of 1 L and weight of 1.5 kg.

The task force first addressed downsizing the electronic control unit (ECU), the brain of the ABS.

The ECU printed circuit board was targeted, to reduce the size to half, namely the size of a business card.

Downsizing microchips would reduce the overall dimensions of the ECU board. For the previous ABS, I/O, drive, and power supply used different ICs as shown in the far right in the figure below.
What if they were combined into a single IC?

No such IC existed, of course.

“You are saying putting everything, including the drive power IC for the solenoid valves, into a single IC. Tell me where we could find an ECU working on a single microchip anywhere in the world.”
“If none exists, then we make it.”

The members were never afraid of trying new things, but the results didn't come easy.

Downsizing the ECU—Integrating Functions into One IC

Packaging functions assigned to three ICs into one would eliminate larger parts, thus downsize the board.

  • Downsizing01 Downsizing01
  • Downsizing02 Downsizing02