Brake Testing

VBOX equipment has led the way in high-accuracy brake testing for more than ten years.

R13 H, R78, R98, ISO 21994 and SAE J2909 testing
Measure braking distance accuracy to within +/-1.8 cm
IMU integration eliminates over-shoot errors for speed brake stops
Pedal force and travel sensor inputs via analogue or CAN
Free brake testing software with five dedicated plugins

Brake Testing with VBOX

Modern electronically controlled braking systems are extremely efficient and are very close to reaching the optimum braking distances for a given tyre and road surface. It is therefore essential that the measurement of braking distances can be carried out with very high distance accuracy.

Due to their high precision, flexibility, and ease of installation (they can be moved from vehicle to vehicle in minutes), VBOX GPS data loggers are used by almost every automotive and tyre manufacturer in the world to carry out brake distance measurements.

Highly Accurate

Using a brake pedal mounted trigger input, VBOX 3i will measure the braking distance to within ±1.8 cm for a typical 100-0 km/h brake stop.

Brake Trigger Input

Our new Pedal Force Sensor with Event Marker measures the amount of force applied to a brake pedal, in accordance to SAE and ECE standards, and automatically triggers the start of a test as soon as any pressure is detected.

Live Display

VBOX Test Suite installed on a Windows device within the test vehicle offers real-time display of all measured parameters. Having instant feedback can save valuable testing time, particularly for more complicated tests such as R139 BAS.

Standard-compliant

VBOX systems enable you to easily conduct brake tests in accordance with ECE R13 H Braking, ECE R90 Brake Pad Testing, ECE R78 Motorcycle Brake Systems, FMVSS135, ADR 31, ISO 21994, and SAE J2909 regulations.

IMU Integration

Using a VBOX Inertial Measurement Unit (IMU) improves accuracy and noise levels, and enhances the dynamic response to velocity. IMU integration also eliminates over-shoot errors and combats satellite drop-out for up to 10 seconds without lock.

Temperature Measurement

Log up to 16 temperature points per tyre with surface temperatures ranging from -20°C to 300°C. The data can be displayed live as a heat map when using a VBOX Touch data logger, or as a graphical overlay when using a VBOX video logger.

Free data analysis software with five Brake Testing plugins

VBOX Test Suite is our user-friendly, intuitive data analysis software that is free to all VBOX users. It makes the process of recording and analysing your test data as quick and easy as possible.

The software comes with five Brake Testing plugins for Trigger brake stops, Speed-to-speed brake stops, homologation testing to ECE R79, SAE J2909, and Category "B" Brake Assist Systems tests to ECE R139.

Testing Equipment

Most braking departments around the world use the VBOX 3i 100 Hz GPS data logger for measuring braking distance, along with a VBOX IMU, to counteract the lever arm effect for speed triggered measurements, or in areas of low GPS visibility. The VBOX 3i measures braking distances to within ±1.8 cm accuracy, which is why it quickly became the industry standard data logger of choice.

The cost-effective 20 Hz VBOX IISX GPS data logger can also be used for braking measurements, and offers braking distance accuracy to within ±10 cm.

VBOX systems are suitable for the following test scenarios:

ECE regulation 13H Braking
ECE regulation R90 Brake Pad Testing
ECE regulation R78 Motorcycle Brake Systems
ECE regulation R139 Category "B" Brake Assist Systems
FMVSS135 regulation
ADR 31 regulation
ISO 21994 standard
SAE J2909
ABS testing and development
Tyre testing and development
AMS testing

Measured Parameters

Trigger speed
Braking distance
Centreline deviation
MFDD
Result statistics
Lateral and Longitudinal G-forces
Brake temperatures (with TC8 or infrared sensors)
Pedal force and travel sensors
Pitch, Roll and Yaw (using the IMU04)

Measure Braking Distance Between Two Speeds

A typical VBOX setup for measuring braking distance between two speeds is a VBOX 3i data logger in conjunction with an Inertial Measurement Unit.

Using an IMU will improve all parameters measured in real-time - therefore enhancing accuracy and noise levels, as well as the dynamic response to velocity.

IMU integration also combats satellite drop-out for up to 10 seconds without lock. The VBOX 3i is compatible with the RACELOGIC IMU 04 module, which additionally provides highly accurate measurements of pitch, roll and yaw rate, as well as x, y, z acceleration via three accelerometers.

Measure Braking Distance Using a Trigger

Depending on the accuracy that you require, we offer a range of GPS measurement systems that can be used for brake testing using a trigger.

VBOX 3i: 100 Hz, CF card logging, 2x CAN interface, 4x 500 Hz analogue inputs, brake trigger input, analogue/digital/RS232 outputs.

VBOX IISX: 20 Hz SD card logging, CAN interface, brake trigger input, analogue/digital/RS232 outputs.

VBOX Speed Sensor: available in a range of update rates from 5 to 100 Hz, our speed sensors are another popular choice if you do not require logging capabilities.

Our new Pedal Force Sensor can also be used with the VBOX 3i, to measure the amount of force applied to a brake pedal, and will automatically trigger the start of a test as soon as any pressure is detected.

Measure Brake Temperatures

Our new Brake Temperature Sensor measures the highly transient surface temperature of a brake rotor at multiple points, making it possible to acquire the time-based temperature distribution across a rotor's surface in order to evaluate & optimize the pad pressure distribution, pad selection, cooling efficiency, braking efficiency, and hot spot formation from thermoelastic instabilities.

The sensor is capable of measuring temperature at 16, 8, 4 points, at a sampling frequency of up to 100 Hz, object temperature between -20 to 950˚C, using CAN 2.0A protocol, and enclosed in a compact IP66 rated aluminium enclosure.

Tyre Temperature Monitoring

Up to four sensors can be installed, that measure up to 16 temperature points on each tyre, with surface temperatures ranging from -20 to 300° C. A dedicated tyre temperature monitoring app for the VBOX Touch data logger presents individual heat maps, as well as live and maximum temperature values, in real-time, on a 4.3" colour display.

Free Brake Testing Software

Want to save time analysing your data? Let VBOX Test Suite do it for you. Our free data analysis software comes with five dedicated Brake Testing plugins for Trigger brake stops, Speed-to-speed brake stops, homologation testing to ECE R79 and SAE J2909 standards, and Category "B" Brake Assist System tests to ECE R139.

Measure pedal application and force

The VBOX Pedal Force Sensor with Event Marker Interface enables you to measure pedal force and activation with just one sensor.

As soon as any pressure is applied to the brake pedal, the interface outputs a digital signal, which can be used to trigger the start of a test. It works similarly to a traditional brake pedal trigger, but also allows for the measurement of pedal force and does not need to be stuck to the pedal.

This gives you a complete solution which measures the amount of force applied to a brake pedal, as well as pedal application, in accordance with SAE J2909 (Braking) and ECE R13H (Braking Assist Systems) regulations.

The VBOX Pedal Force Event Marker Interface constantly monitors the pedal force sensor voltage and adjusts the trigger threshold. This accounts for any fluctuations in pedal force caused by changes in temperature of the sensor itself, preventing incorrect trigger activation.

How we verify brake distance accuracies?

We regularly verify the brake test measurements obtained by VBOX systems against a light barrier, laser, and RTK DGPS setup with Base Station to confirm its high positional accuracy.

We also capture the test on our LabSat GPS simulator, which records the raw GPS signals and the brake trigger input, and allows us to replay it through any VBOX on the bench. This gives us a repeatable reference to check against any new firmware or hardware updates, and maintains a high standard of brake testing accuracy.

GPS Accuracy

How do you derive velocity, distance, position & vehicle body attitudes from GPS? Which factors are crucial in producing accurate measurements for vehicle testing?

Find out more

Increased Accuracy with RTK

What is Real Time Kinematic (RTK)? How do you increase the accuracy of GPS signals using RTK? What are the limitations?

Find out more

Brake testing using IMU integration

Conducting brake tests on tall vehicles with long suspension travel can result in a speed overshoot of the velocity data, due to the measurements being taken at the high roof position of the GPS antenna. As the brakes are initially applied, there is a higher rate of change in velocity at the roof than there is at the vehicle's centre of gravity (COG).

However, the integration of an Inertial Measurement Unit, such as the RACELOGIC IMU 04 module, can be used to counteract this 'lever-arm' effect, by placing the IMU at the COG, which measures the vehicle pitch as it brakes. This data, when combined with that from GPS, provides compensation for the overshoot and allows for consistent brake stop testing.

Counteracting the lever-arm effect will also aid test engineers when conducting high-dynamic manoeuvres other than brake stops. In slip angle measurements the speed overshoot can occur if the antenna is moving through a greater arc of travel than that of the vehicle's centre of gravity as it corners. Procedures such as lane change manoeuvres can therefore also benefit from IMU integration and lever-arm compensation.

Point A has travelled further than point B.

This graph shows how point A has travelled further than point B.

Blue trace = GPS Speed; Red trace = IMU-corrected data

In this example of a high-dynamic brake stop, the blue trace (GPS Speed) overshoots at the initial point of brake application, and then exhibits a damped oscillation as the deceleration continues. The IMU-corrected data (red trace) accurately records the brake stop from the vehicles centre of gravity.

Red (below) = Pitch measured by the IMU; Blue = GPS speed; Red = IMU integrated GPS speed

The traces between the green and red vertical lines are of a car going over a speed hump. Note how the GPS speed alters as the vehicle roof moves independently of the COG as it goes over the hump. The integrated speed logs the correct speed of the vehicle.