Integrated Braking

A next-generation braking technology in which a single electronic control unit integrates and manages multiple braking sources such as friction braking and regenerative braking, optimizing braking per

Integrated Braking

Overview

Integrated Braking refers to a braking architecture in which a single electronic control unit (ECU) integrates and manages hydraulic friction braking, motor regenerative braking, and safety control functions that previously existed as separate modules, such as ABS, ESC, and TSC. By replacing the traditional vacuum booster + master cylinder structure with a pedal simulator and electronic actuator, it can shorten braking response time from hundreds of milliseconds to tens of milliseconds and maximize regenerative energy recovery. Driven by the spread of electric and hybrid vehicles, autonomous driving, and the software-defined vehicle (SDV) trend, its application areas have been rapidly expanding in the 2020s from passenger cars to commercial vehicles, railways, and aircraft.

Main Content

Definition and Background

Traditional braking systems were centered on mechanical and hydraulic structures in which, when the driver pressed the pedal, a vacuum booster amplified the force, and the master cylinder generated hydraulic pressure to push the calipers. As ABS and ESC were added as separate hydraulic modules, the number of parts and pipes increased, and coordination with regenerative braking was limited. Integrated braking reorganizes this structure around electrical signals. The key is the Brake-by-Wire concept, in which the pedal and hydraulic system are mechanically separated; pedal input is read by sensors, calculated by the ECU, and then actual pressure is generated by a motor pump and solenoid valves.

Components

Pedal simulator: Artificially creates pedal reaction force to deliver a natural pedal feel to the driver.
Electric motor pump and hydraulic cylinder: Precisely controls required pressure.
Solenoid valve block: Distributes pressure per wheel and performs ABS/ESC functions.
ECU and sensors: Fuses pressure, wheel speed, yaw rate, and steering angle sensors.
Redundant circuits: Ensures fail-safe operation through redundancy of power, communication, and hydraulic lines.

Depending on the structure, systems are divided into One-Box, which integrates the master cylinder and booster (e.g., Continental MK C1/C2, Bosch iPB), and Two-Box, which combines only an electronic booster while retaining the existing ESC (e.g., Bosch iBooster+ESP). One-Box is lightweight and highly integrated, but NVH and pedal feel tuning are difficult; Two-Box has lower development risk but is larger and heavier.

Operating Principle and Regenerative Braking Cooperative Control

When the driver presses the pedal, the ECU calculates the required deceleration and preferentially uses the drive motor's regenerative braking. It determines the recoverable torque by considering battery SOC, motor torque limits, low-temperature conditions, etc., and supplements only the insufficient braking force with friction braking; this is blending or cooperative braking. At this time, if deceleration changes abruptly in the transition from regenerative braking to friction braking, the driver may feel a sense of dissimilarity, so precise torque coordination that maintains deceleration continuity is essential. Integrated braking has a decisive advantage in that it can flexibly implement this cooperative control in software.

Advantages and Challenges

Advantages include ① improved energy recovery rate (cases of 10–25% improvement in driving range during city driving), ② improved braking response speed and precise control, ③ weight reduction and packaging freedom due to fewer parts, ④ updates to pedal feel and braking sensitivity through OTA, and ⑤ the possibility of direct interfacing with autonomous driving systems.

Challenges include ① functional safety requirements to guarantee braking even when power or communication is lost (ISO 26262 ASIL-D), ② securing a natural pedal feel, ③ high initial development costs and reorganization of the maintenance ecosystem, and ④ fault diagnosis and parts supply issues.

Application Areas

Passenger electric and hybrid vehicles: The standard architecture for regenerative cooperative braking.
Commercial vehicles and buses: Combination of pneumatic integrated braking (EBS) and electric drive.
Rail vehicles: Adhesion and adhesion-limit control that blends electric braking and pneumatic braking.
Aircraft: Brake-by-wire-based electronic braking systems.
Autonomous shuttles and robotaxis: Redundant integrated braking has been codified as a safety requirement.

Latest Trends

The biggest change in the integrated braking market in 2024–2025 is the popularization of One-Box. Continental MK C2, Bosch iPB, ZF IBC, etc. are spreading to small and mid-sized electric vehicles, and low-cost One-Box products from Chinese parts companies (Betop, Nabotech, etc.) are rapidly eroding global market share. In Korea, Hyundai Mobis and HL Mando have joined the competition by mass-producing and supplying integrated braking modules.

The second trend is preparation for EMB (Electro-Mechanical Brake). This method eliminates hydraulic pipes themselves and places an electric caliper at each wheel, and pilot production has been discussed in Europe and China after 2025. If hydraulics disappear, braking becomes a fully software function and naturally combines with SDV architectures.

On the regulatory side, in addition to existing regulations such as UN R13-H and FMVSS 135, redundancy and backup braking requirements for L3 and higher autonomous driving are being strengthened, and cybersecurity regulations (UN R155) and software update regulations (UN R156) directly apply to brake ECUs as well. In addition, research on AI-based controllers that optimize the distribution between regenerative braking and friction braking in real time, and predictive maintenance services linked to brake wear prediction, are establishing themselves as major trends in 2025.