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Understanding Vehicle Motion

ESC & Handling Validation with Dynamics Duo

The VBOX 4 and IMU05 combine to deliver CG-referenced, time-aligned measurement of vehicle motion – built for ESC calibration, handling balance work, and regulatory compliance testing.

100 Hz output rate
0.02° RMS Pitch / roll angle
0.15° Slip angle accuracy
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THE CHALLENGE

Why ESC and handling tests are hard to measure accurately

Fast manoeuvres, system interventions, and poor sensor placement combine to make cause-and-effect ambiguous. These are the problems Dynamics Duo is designed to resolve.

01

Signals that don't share a reference

Steering input, yaw and lateral acceleration are sometimes recorded from different points on the vehicle with different timestamps, making vehicle performance difficult to interpret reliably.
02

Data biased by mounting position

Sensors, such as GNSS antennas mounted at roof height exaggerates roll and introduces lever-arm errors in speed and lateral acceleration. During aggressive manoeuvres, this can compound into significant measurement errors.

03

Noise that obscures stability margins

Subtle changes in handling balance – understeer gradient shifts, yaw rate gain variation – are easily masked by sensor noise when data quality is marginal. ESC tuning decisions made on noisy data carry risk.

04

Separating driver action from system response

During ESC activation events, understanding whether the vehicle's behaviour was caused by the driver or the stability system requires simultaneous, synchronised capture of both. Any gap in the data creates ambiguity.

THE SYSTEM

Two instruments. One coherent measurement.

VBOX 4 provides high-accuracy GNSS-based speed, position and trajectory. IMU05 adds low-noise inertial data at the CG. Together they produce a single unified picture of vehicle motion.

VBOX 4
GNSS Data Logger

VBOX 4

100 Hz GNSS measurement engine with dual-antenna heading, CAN data logging and real-time output. The foundation for speed, position and path measurement.

  • GNSS update rate 100 Hz
  • Position accuracy (standalone)H: 1.2 m; V: 1.8 m
  • Velocity accuracy 0.1 km/h RMS
  • CAN ports 2 × CAN + 2 x CAN FD
  • RTK accuracy (optional) V: 10 mm + 0.8 ppm·BL; H: 5 mm + 0.5 ppm·BL
  • Slip angle calculation At up to 5 vehicle positions
 IMU05
Inertial Measurement Unit

IMU05

Low-noise 6-axis inertial measurement unit. Mounted at a convenient location on the vehicle; lever-arm compensation translates all measurements to the centre of gravity for analysis.

  • Gyro range ±450°/s
  • Gyro bias stability ±1.2°/h
  • Angle random walk 0.08°/√h
  • Accel range ±4 g
  • Accel bias stability 14 µg
  • IP rating 67
Data from the VBOX 4, IMU05 and other data sources are merged fully synchronised on a single time base to allow accurate analysis.

WHY DYNAMICS DUO

Four things engineers need. All resolved in one setup.

01 / 04

CG-referenced vehicle motion

For handling analysis, measurements must reflect how the vehicle moves at its true centre of gravity, not at an arbitrary mounting point.

  • Speed and slip angle referenced to the CG
  • Longitudinal and lateral acceleration at the CG, not the roof
  • Accurate vehicle trajectory for path and corridor analysis
02 / 04

Clean data in dynamic manoeuvres

Noisy or biased inertial data makes vehicle behaviour hard to read, especially in the transient phase where accurate measurement is most critical for ESC validation.

  • Pitch and roll measured cleanly during rapid steering events
  • Accurate Yaw rate and lateral acceleration in aggressive manoeuvres
  • Low noise, low drift measurements for consistent testing
03 / 04

Clear separation of driver and ESC actions

To understand ESC behaviour, you need to know what the driver did and what the system did in response. This requires synchronised capture of all relevant signals:

  • Vehicle CAN data such as ESC status, steering angle and wheel speeds
  • Yaw rate and slip angle time-aligned with vehicle CAN data
04 / 04

One setup across the full programme

From regulatory ESC tests to steady-state handling and OEM development work, a single installation covers the measurement requirements throughout the stability programme.

  • ISOFIX mount for fast vehicle changes (typically < 10 min swap)
  • Real-time output confirms run validity on track
  • Compatible with RTK correction for path-accuracy-critical tests

REGULATORY & INDUSTRY STANDARDS

Standards and test frameworks supported

Dynamics Duo provides the measurements needed to assess response, stability, and intervention behaviour across a broad range of regulatory and OEM test requirements.

Standard Manoeuvre Measurement challenge How Dynamics Duo helps
UNECE R140ESC Regulation (Global) Sine with dwell, lane change on low-µ Separating driver input from ESC action; yaw response timing under intervention CG-referenced yaw, slip and lateral acceleration — time-aligned with CAN ESC status
FMVSS 126US Federal Standard Sine with dwell (1 Hz, 0.5 Hz variants) Steering–yaw phase lag; noisy yaw in high-frequency transients Low-lag yaw and slip on one time base — accurate intervention timing measurement
ISO 3888-2Double Lane Change Double lane change (elk test) Path corridor compliance within tight tolerances; roof-biased motion during transients CG-true trajectory and yaw for corridor analysis RTK recommended
ISO 3888-1Obstacle Avoidance Obstacle avoidance lane change Speed-dependent path deviation; yaw overshoot after course exit Slip angle and yaw time-history; trajectory vs cone corridor overlay
ISO 4138Steady-State Circular Constant radius / constant speed sweep Noise masks understeer gradient changes; CG vs wheel measurement discrepancy Low-noise yaw rate gain and lateral acceleration at the CG
ISO 7401Transient Response Step steer, ramp steer, sinusoidal steer Delayed or noisy signals obscure rise time and overshoot measurement Time-aligned steering, yaw and slip with low lag — accurate response time measurement
ISO 11026High-Speed Sinusoidal Sine sweep (frequency ramp) Lateral acceleration and yaw rate amplitude accuracy at 1–2 Hz; phase measurement High sample rate GNSS-IMU fusion maintains accuracy through the frequency range
OEM ESC ProtocolsInternal / Benchmarking Manufacturer-specific calibration sequences Inconsistent reference points when comparing variants or competitors Single CG-referenced motion reference simplifies variant-to-variant benchmarking
UNECE R140ESC Regulation (Global)
Manoeuvre
Sine with dwell, lane change on low-µ
Challenge
Separating driver input from ESC action; yaw response timing under intervention
How Dynamics Duo helps
CG-referenced yaw, slip and lateral acceleration — time-aligned with CAN ESC status
FMVSS 126US Federal Standard
Manoeuvre
Sine with dwell (1 Hz, 0.5 Hz variants)
Challenge
Steering–yaw phase lag; noisy yaw in high-frequency transients
How Dynamics Duo helps
Low-lag yaw and slip on one time base — accurate intervention timing measurement
ISO 3888-2Double Lane Change
Manoeuvre
Double lane change (elk test)
Challenge
Path corridor compliance within tight tolerances; roof-biased motion during transients
How Dynamics Duo helps
CG-true trajectory and yaw for corridor analysis RTK recommended
ISO 3888-1Obstacle Avoidance
Manoeuvre
Obstacle avoidance lane change
Challenge
Speed-dependent path deviation; yaw overshoot after course exit
How Dynamics Duo helps
Slip angle and yaw time-history; trajectory vs cone corridor overlay
ISO 4138Steady-State Circular
Manoeuvre
Constant radius / constant speed sweep
Challenge
Noise masks understeer gradient changes; CG vs wheel measurement discrepancy
How Dynamics Duo helps
Low-noise yaw rate gain and lateral acceleration at the CG
ISO 7401Transient Response
Manoeuvre
Step steer, ramp steer, sinusoidal steer
Challenge
Delayed or noisy signals obscure rise time and overshoot measurement
How Dynamics Duo helps
Time-aligned steering, yaw and slip with low lag
ISO 11026High-Speed Sinusoidal
Manoeuvre
Sine sweep (frequency ramp)
Challenge
Lateral acceleration and yaw rate amplitude accuracy at 1–2 Hz; phase measurement
How Dynamics Duo helps
High sample rate GNSS-IMU fusion maintains accuracy through the frequency range
OEM ESC ProtocolsInternal / Benchmarking
Manoeuvre
Manufacturer-specific calibration sequences
Challenge
Inconsistent reference points when comparing variants or competitors
How Dynamics Duo helps
Single CG-referenced motion reference simplifies variant-to-variant benchmarking

WHAT YOU CAN MEASURE

Objective, reproducible parameters for dynamics testing

The parameters below are direct outputs of the VBOX 4 + IMU05 combination unless noted. All are logged, time-aligned and available for real-time display and post-test analysis.

Steering & response

  • Yaw rate
  • Steering angle
  • Lateral acceleration (CG)
  • Understeer / oversteer behaviour

Steering angle: sourced from vehicle CAN or optional sensor – not a native GNSS/IMU output.

Body slip & balance

  • Body slip angle at the CG
  • Lateral acceleration at the CG
  • Roll and pitch angle

Individual tyre slip angles require additional wheel angle information.

Path & corridor

  • Vehicle trajectory
  • ISO 3888-1/2 corridor compliance
  • Speed and distance throughout test
  • Lateral deviation from centreline

Centimetre-level path accuracy requires RTK correction (NTRIP or base station).

ESC & stability systems

  • ESC activation timing (via CAN)
  • Yaw change at and after ESC intervention
  • Wheel speed and slip measurement

SOFTWARE & ANALYSIS

VBOX Test Suite – Analysis built for dynamics work

VBOX Test Suite supports your entire test workflow – from live track-side monitoring through to regulatory submission – all within a single platform. Engineers can compare runs, overlay channels from identical test conditions, and export to downstream tools without conversion.

  • Live data display for real-time pass/fail feedback at the trackside
  • Vehicle trajectory overlay for path comparison
  • Multi-run overlay with channel alignment – compare back-to-back or vehicle-to-vehicle
  • Customisable workspace combining charts, maps, and synchronised HD video
  • Automated report generation for regulatory submissions

Data export formats

All VBOX data can be exported for use in other analysis tools such as MATLAB and Python.

.vbbNative VBOX format
.csv Excel & Python compatible
.matMATLAB / Python compatible
.txtTab-delimited text

VBOX CAN output is available for real-time integration with external data acquisition systems.

Ready to discuss your ESC or handling programme?

Our engineers understand the demands of stability and handling validation work. Contact us to discuss your specific test requirements, vehicle types and preferred standards.

Speak to a VBOX engineer