steeringbywire

Steering by wire, also called steer-by-wire, is a method of steering a vehicle in which the steering wheel’s input is not transmitted to the wheels through a mechanical linkage. Instead, steering wheel position and torque are sensed by sensors and converted into electronic signals that drive actuators at the wheels or steering mechanism.

The system typically includes sensors to detect steering wheel angle and applied torque, an electronic control unit that processes the data together with vehicle state information, and electric or hydraulic actuators that turn the wheels. Redundancy and fault-tolerant design are standard, with duplicate sensors and dual actuators connected to independent power and communication paths. The system can deliver steering feel to the driver via haptic feedback and can adjust steering ratio and assist level dynamically to suit speed, road condition, or driving mode.

Full steer-by-wire replaces the mechanical linkage entirely, removing any direct physical connection between the steering wheel and the wheels. Some configurations use a hybrid approach that retains a mechanical backup or partial linkage for safety. In all cases, the system must protect against sensor failure, actuator jam, and cyber threats, and it relies on robust fault management and secure communications.

Advantages of steer-by-wire include flexible packaging and potential weight savings, the ability to vary steering ratio and assist level, and tighter integration with driver-assistance and autonomous driving systems. It also enables more sophisticated vehicle dynamics control and can simplify routing of controls and sensors in modern, feature-rich architectures.

Key challenges are ensuring high reliability and safety, managing cybersecurity risks, and meeting regulatory and certification requirements. Standards for functional safety (such as ISO 26262) and evolving automotive cybersecurity guidelines guide design, testing, and verification. Adoption has been selective, with concept vehicles and some premium applications driving further development.