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BRAKE TESTING WITH VBOX - SYSTEM FEATURES

Features

  • GPS based measurement of speed and distance
  • Easy to fit, simple to use
  • Braking distance accuracy +/-1.8cm
  • Pedal force and travel sensor inputs via analogue or CAN
  • Live and logged results
  • Customisable tests
  • ADR 31, ADR 33, ADR 35, FMVSS135 and ECE13, R13H compatible
  • Measurement of longitudinal G-forces
  • Centre of gravity correction by combined use of GPS and inertial systems
  • Specific brake testing software available
  • Multiple brake temperature logging using thermocouple inputs
  • IMU integration eliminates over-shoot errors for speed to speed brake stops
vbox motorcycle brake test

Measured Parameters

  • Trigger speed
  • Braking distance
  • Centreline deviation
  • MFDD and average from start (a = v2-u2/2s)
  • Result statistics
  • Lateral and Longitudinal G-forces
  • Brake temperatures (TC8 module required)
  • Pedal force and travel sensors
  • Pitch, Roll and Yaw (if using the IMU04)

Live Results

A laptop or tablet PC running VBOX Brake Test software can be used to monitor the measured parameters in real time, either by a serial, USB, or Bluetooth connection.

This package also allows for detailed post processing of the logged data in sync with any video footage recorded by a Video VBOX.

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 IMU04 with a suitably upgraded VBOX 3i 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 a compensation for the overshoot and allows for consistent brake stop testing.

IMU lever arm

The graphs below show how point A has travelled further than point B:

IMU lever arm effect in high dynamic brake stop

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.

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 benefit from IMU integration and lever-arm compensation.

IMU lever arm effect in high dynamic manoeuvres

Orange = Pitch measured by the IMU Blue = GPS speed Red = IIMU itegrated 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.

IMU Integration

However, the integration of an IMU04 with a suitably upgraded VBOX 3i 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 a compensation for the overshoot and allows for consistent brake stop testing.

Dedicated Brake Test Software

VBOX Brake Test software is designed for customers who are performing multiple high dynamic brake stop tests using a VBOX 100Hz data loggers and speed sensors.

The software is able to process both live serial data and recorded VBO files in order to generate results from either brake trigger or deceleration tests. This allows customers to perform multiple brake stop tests and view the results in a useful format.

This software has been developed on conjunction with brake test engineers to reduce test track time and simplify analysis.

Brake Test overview plugin

Video Integration

Video integration enables engineers to have a graphical representation of the test over live footage, enhancing the data for quick fault analysis and to aid presentations.