For electric power steering (EPS) control, I generally consider the steering torque sensor and the electric motor position sensor to be the core sensors. The torque sensor tells the controller how much assistance the driver is requesting, while the motor position sensor provides rotor angle and speed information for accurate commutation and control. Depending on the vehicle architecture, the EPS controller may also use steering angle, vehicle speed, motor current, motor temperature, supply-voltage, wheel-speed, and yaw-rate data.
If you are looking for more details, kindly visit our website.
The exact sensor set depends on whether the system is column-assist, pinion-assist, or rack-assist, as well as on the vehicle network and functional safety requirements. At QEXPAND, I help buyers evaluate these inputs as part of a complete motor controller and electric power steering controller solution. The objective is not simply to add more sensors, but to select the minimum reliable measurement set required for stable assistance, diagnostics, protection, and vehicle integration.
The steering torque sensor measures the effort applied by the driver to the steering wheel or steering shaft. The EPS controller uses this signal to determine the direction and approximate level of motor assistance required. In many systems, the sensor includes redundant signal channels so the controller can compare outputs and identify disagreement or signal failure.
Torque sensors may use magnetic, magnetoresistive, strain-based, or other sensing technologies, depending on the mechanical design and required interface. When I review a torque sensor for a project, I check its measurement range, zero stability, redundancy, linearity, temperature behavior, and communication or analog output format. A controller cannot deliver predictable assistance if the torque signal has excessive noise, drift, or an unsuitable response time.
The motor position sensor provides rotor angle information to the EPS controller. This information allows the controller to energize the motor phases in the correct sequence and regulate torque more accurately. It also helps the controller determine motor speed and detect conditions such as an implausible position signal or stalled rotation.
Common choices include Hall-effect sensors, magnetic angle sensors, resolvers, and encoders. The appropriate option depends on motor construction, available space, environmental conditions, resolution requirements, and controller interface. For a compact automotive motor controller, I normally confirm the sensor’s electrical levels, number of channels, angular resolution, maximum speed, and behavior during startup before approving the design.
Motor current measurement is an important feedback and protection input. The controller uses current information to regulate motor torque, identify overcurrent conditions, estimate electrical load, and protect power-stage components. Current sensing may be implemented with shunt resistors, Hall-effect current sensors, or integrated measurement circuits.
The required accuracy depends on the control strategy and the motor power stage. As a practical engineering reference, a 12 V EPS system may operate with a nominal supply near 12 V while experiencing a wider operating range during starting, charging, and transient conditions. I therefore recommend defining the current range, bandwidth, isolation requirements, sampling method, and diagnostic thresholds rather than selecting a sensor only by its nominal ampere rating.
A steering angle sensor measures the position or movement of the steering wheel or steering column. It can support steering-angle-based assistance maps, return-to-center behavior, calibration, vehicle stability functions, and driver-assistance features. In some vehicle designs, the angle signal is integrated with another steering module and transmitted to the EPS controller over CAN rather than measured directly inside the motor controller.
I distinguish the torque sensor from the steering angle sensor during system planning. Torque primarily represents driver effort, while angle represents steering position and movement. Some EPS applications can provide basic assistance without a dedicated angle sensor at the EPS controller, but advanced coordination and diagnostic strategies may require it.
Vehicle speed is commonly used to vary steering assistance. A system may provide lighter steering effort at low speed and reduced assistance at higher speed, but the actual calibration is application-specific and must be validated by the vehicle manufacturer. The speed value may come from individual wheel-speed sensors, a vehicle control module, or the CAN network.
Wheel-speed signals can also support plausibility checks and coordination with anti-lock braking and electronic stability systems. I advise buyers to confirm whether the EPS controller needs a direct sensor input, a CAN message, or both. This decision affects connector design, software integration, network diagnostics, and responsibility for signal validation.
Temperature measurement protects the motor, inverter, current-sensing components, and controller electronics from excessive thermal stress. Depending on the design, temperature may be measured at the motor winding, power semiconductor, PCB, or housing. The controller can use this information to reduce assistance or apply a protective strategy when temperature exceeds a defined limit.
QEXPAND contains other products and information you need, so please check it out.
Supply-voltage measurement is also essential for detecting undervoltage, overvoltage, abnormal charging conditions, and power interruptions. A 12 V electrical system can experience voltage events outside its nominal value, so I recommend reviewing the full operating and transient specification. The controller should define what assistance behavior is expected during voltage loss, restart, and intermittent supply conditions.
Some EPS systems receive yaw-rate, lateral-acceleration, brake-pressure, or driver-assistance signals from other vehicle controllers. These inputs may be used for stability coordination, lane-keeping support, automated parking, or torque overlay functions. They are not universally required for basic electric assistance, and their inclusion depends on the vehicle’s electronic architecture.
For this reason, I do not recommend treating every possible vehicle signal as a mandatory EPS sensor. Instead, I separate inputs into three groups: direct control inputs, protection inputs, and networked coordination inputs. This structure helps engineering teams avoid unnecessary hardware while preserving the interfaces needed for future software or vehicle-level functions.
| Sensor or Signal | Primary Purpose | Key Specifications to Review |
|---|---|---|
| Steering torque | Driver-intent detection | Range, redundancy, offset, linearity, noise, interface |
| Motor position | Commutation and rotor feedback | Resolution, speed, phase alignment, startup behavior |
| Motor current | Torque control and protection | Measurement range, accuracy, bandwidth, isolation |
| Temperature | Thermal protection | Location, operating range, response time, diagnostic limits |
| Vehicle speed | Assistance calibration | CAN format, update rate, plausibility, fallback strategy |
Signal timing is as important as sensor accuracy. For example, a sensor update rate of 100 Hz represents a 10-millisecond update interval, but that does not by itself guarantee suitable closed-loop performance because filtering, software scheduling, and network latency also contribute. I therefore evaluate the complete signal path from sensing element to controller software.
For a basic EPS application, the core configuration generally includes a steering torque sensor, a motor position sensor, motor current measurement, temperature monitoring, and supply-voltage measurement. Vehicle-speed information is commonly added to support assistance calibration. This configuration establishes the essential feedback and protection functions without assuming advanced driving features.
Applications involving lane keeping, automated parking, or steering torque overlay may require additional steering-angle, yaw-rate, lateral-acceleration, and vehicle-status signals. In these cases, the EPS controller must handle commands from another control unit while still preserving driver override, diagnostics, and safe fallback behavior. I recommend defining message ownership, signal priority, timeout behavior, and torque limits at the beginning of the project.
Special vehicles may not provide the same network signals as passenger cars. In that situation, a controller may need dedicated analog, PWM, pulse, or digital inputs for speed, angle, and safety status. The mechanical interface, motor rating, environmental sealing, and wiring strategy can be as important as the sensor selection itself.
One common mistake is specifying only the sensor type while ignoring the controller interface. A Hall sensor, resolver, or magnetic angle sensor is not automatically interchangeable because each may require different excitation, conditioning, calibration, and software support. I also see projects where buyers define nominal voltage but do not define current peaks, thermal conditions, EMC expectations, or fault behavior.
Another mistake is assuming that vehicle-speed and wheel-speed data are always available to the EPS controller. The source, message format, update interval, and fallback value must be confirmed with the vehicle network owner. Finally, buyers should not treat a prototype sensor configuration as production-ready until calibration, redundancy, diagnostics, environmental testing, and system-level validation are addressed.
At QEXPAND, I approach EPS sourcing as a system-integration task rather than a standalone sensor purchase. We can help buyers organize the motor controller requirements, sensor interfaces, power-stage parameters, communication needs, connector definitions, and installation constraints. This process is useful when the project requires a controller matched to a specific motor, torque sensor, position sensor, or vehicle network.
Before requesting a quotation, I recommend preparing the motor voltage, continuous and peak current, sensor types, signal formats, CAN requirements, operating temperature, mounting conditions, expected quantity, and target delivery schedule. If some parameters are not finalized, we can begin with a requirements review and identify which values must be measured or confirmed. Clear technical information reduces redesign risk and makes supplier comparison more meaningful.
The most important sensors for electric power steering control are the steering torque sensor and motor position sensor, supported by motor-current, temperature, and supply-voltage measurements. Vehicle-speed and steering-angle signals are commonly required for refined assistance and vehicle integration, while wheel-speed, yaw-rate, and other signals depend on the application architecture. Some inputs may be connected directly, while others may arrive through CAN.
My recommended next step is to map every sensor by function: driver intent, motor control, protection, vehicle coordination, or diagnostics. Then confirm its range, accuracy, redundancy, electrical interface, update rate, environmental rating, and failure response. Contact QEXPAND with your motor and vehicle-controller specifications, and I can help you identify a practical EPS motor controller and sensor interface configuration for your project.
For more What Sensors Are Required for Electric Power Steering Controlinformation, please contact us. We will provide professional answers.