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STEERING TEST SYSTEMS

CHARACTERIZATION • FATIGUE • DYNAMIC EVALUATION

VEHICLE DYNAMICS

BIA has developed an efficient and flexible test solution to perform dynamic tests on complete

steering sub-system. By simulating its real environment, the test system evaluates accurately the

steering behavior in any configuration.

By simulating loads applied on steering wheel and steering rack, BIA test system

can performed relevant dynamic tests :

• Violent wheel swerve :

acceleration up to 15 000 °/s with 6 000 N resistance force on rack

• Wheel release after wheel turn :

steering column behavior after wheel releasing, under real load on the rack

• Frequency characterization (direct or reverse) :

system response measurement under vibration (force/displacement)

• Derating :

power electronics failure analysis

For characterization of steering column, two optional modules are

available to perform measurement of twist rigidity, friction torque and

homokinetic defects.

• Columns and steering assembly positioned in real

configurations

• High dynamic actuator to evaluate steering behaviour

• Power for steering assistance (electric or hydraulic) with

CAN communication

• User-friendly software with customizable interface

• Steering column characterization with optional modules

• Simulation of climatic conditions available, including

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Loading Actuators

BIA solution integrates three main actuators: one electric motor simulating driver’s action on

steering wheel and two hydraulic cylinders applying load or displacement on steering rack. Each

actuator can be closed loop controlled in displacement, speed or force. Hydraulic power pack is

also available.

Power assistance modules can be added either for hydraulic or electric assistance systems.

Corresponding information are simulated through CAN communication to control vehicle electronic

commands.

Optional modules are also available to characterize steering column :

• A sub-unit to provide torque and measure angle at the steering column end

• A sub-unit with low friction bearing & calibration arm

STEERING WHEEL ACTUATOR

It simulates the driver of the vehicle by providing active and reactive torque. It allows adjustments

in every direction to meet vehicle configuration.

• Max. torque at low speed 56 Nm

• Min. angular velocity 0.1 °/s

• Max. angular velocity 2000 °/s

• Closed loop control in speed, torque or position

The torque meter is calibrated for two different ranges:

• Up to 50 Nm accuracy of 0.1 Nm

• Up to 5 Nm accuracy of 0.05 Nm

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Loads on the steering rack are provided by two hydrostatic bearing cylinders. Each actuator can

be adjusted in Z axis to match with real configuration.

• Max. load 9 kN

• Stroke 200 mm (LVDT position sensor)

• Max. speed 0.5 m/s (0.3 m/s dynamic)

Closed loop control in position / load

• Precision ± 0,1% from 0 to 25 Hz

• Frequency Max. 25 Hz

LOADING ACTUATOR ON STEERING RACK 2A 2B

As a turnkey solution, BIA can provide climatic chamber to simulate

environmental conditions. Temperature ranges from -40°C to +140°C.

Humidity production and mud sputtering device are also available.

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Complementary Modules

STEERING POWER ASSISTANCE

ELECTRIC POWER SUPPLY FOR STEERING ASSISTANCE

Electric power supply provides stable energy to the EPS & HPS in this electric cabinet. This

station is mobile and can be used either on characterization or durability zone.

Voltage and current are controlled by test cycle. This station is also connected to the BMC system

in order to communicate with CAN bus. Two input signals are simulated to control electronic

vehicle command: vehicle speed and engine speed.

• Power Constant regulation

• Adjustable Voltage 0 to 18 V

• Current output 150 A

• Voltage or intensity Control by outside input

Intensity measurement

• Type Shunt measurement

• Range 200 A

• Accuracy 0.5%

HYDRAULIC POWER SUPPLY FOR STEERING ASSISTANCE

BIA can provide hydraulic power for steering assistance. Hydraulic circuit should be similar to

vehicle circuit volume, about 1 liter. Flow, pressure and temperature measurements are

integrated in the circuit.

When real pump of hydraulic power assistance is connected, an

asynchronous motor providing variable speed drives it. The pump is

fixed on the motor by an interface. Several different interfaces can

be provided.

• Speed 0 to 1500 rpm

• Power 7.5 kW

• Torque 49 Nm

In any case, a communication module of the control system generates actual electric signals to

simulate sensors or required information for ECU. The communication flow is created through

CAN protocol. DBC files can be imported.

Voltage measurement

• Full Scale 20 V

• Accuracy 0.1% FS

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OPTIONAL MODULES, STEERING COLUMNS CHARACTERIZATION

For characterization of steering column, two optional modules are available to perform

measurement of twist rigidity, friction torque and homokinetic defects.

Sub-unit providing torque and measuring angle at the column’s end

When the system is used without steering rack, this module provides torque on the column’s end

through an electrical Brushless servo-motor:

• Max. torque in rotation 10.6 Nm

• Max. angular velocity 2000 °/s

• Inertia 0.023 kg.m²

• Feedback accuracy 0.1 Nm (in torque, in static)

Low friction sub-unit

This module is used for tests without steering rack which require low residual friction.

It can be oriented in order to realize angular measures. Its rotation can be locked.

• Setting in RY ± 45°

• Setting in RZ ± 360°

• Only 0.03 Nm residual friction torque in pinion shaft bearing

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BIA Control System

BMC800 CONTROLLER

The standard BIA controller (BMC 800) is used to control the complete test

system. It provides closed loop control for each axis, conditioning for sensor

signals and integrates data acquisition module. Many types of sensors can

be plugged, such as torquemeter, load cell, LVDT, flowmeter, pressure and

temperature sensors, etc… For steering assistance system, full

communication under CAN protocol is available.

A remote control with programmable display is available

for remote operation and monitoring.

UTM CONTROL SOFTWARE

As a single package, BMC800 is supplied with UTM software which provides powerful control

functions in a user-friendly environment.

The UTM software provides an easy-to-use “drag and drop” environment for building standard

and non-standard sequences. In this environment, it is possible to link basic processes, including

function generation (sinus, square, triangle, pause, imported file, etc…), data acquisition, events,

and triggers, to quickly and easily build complex tests.

Moreover, specific function provides the possibility to create customized control screens for test

monitoring with graphical representation of any channel. Test report and standard data export are

available too.

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