Electronic Braking and Aid to Vehicle StabilityBradford University1 GRRF Ad-Hoc Working Group Electronic Vehicle Stability Control “Trailers” 25 – 26 November 2004 Document No. EVSC04-05

Electronic Braking and Aid to Vehicle StabilityBradford University2 T railer I nduced R oll O ver

Electronic Braking and Aid to Vehicle StabilityBradford University3 Number of Roll Over Accidents UK Roll Over Statistics - Heavy Commercial Vehicles Rigids Articulated

Electronic Braking and Aid to Vehicle StabilityBradford University4 Causes of Roll-Over: Driver misjudgement of speed & road conditions

Electronic Braking and Aid to Vehicle StabilityBradford University5 Causes of Roll-Over: Collision avoidance

Electronic Braking and Aid to Vehicle StabilityBradford University6 Considerations: It is NOT possible to prevent ALL roll overs Vehicle is “Tripped” Many roll overs are the result of loss of concentration and minor misjudgement of road conditions Excessive over speed

Electronic Braking and Aid to Vehicle StabilityBradford University7 Position of load Centre of gravity Effective track Vehicle speed Primary Roll Over Factors: Primary Roll Over Factors: Radius of turn

Electronic Braking and Aid to Vehicle StabilityBradford University8 Road camber Roll stiffness Torsional chassis stiffness Load shift Secondary Roll Over Factors: Secondary Roll Over Factors: Fifth wheel coupling Tyre Pressure

Electronic Braking and Aid to Vehicle StabilityBradford University9 Trailer ABS & EBS Functionality:

Electronic Braking and Aid to Vehicle StabilityBradford University10 Conventional Semi-Trailer Anti-Lock Braking System ECU ISO 7638 (5 Pin) 2S/2M or 4S/2M Independent Control

Electronic Braking and Aid to Vehicle StabilityBradford University11 Semi-Trailer Electronic Braking System ISO 7638 (7 Pin) 42 ECU S/2M or 4S/2M Independent Control

Electronic Braking and Aid to Vehicle StabilityBradford University12 Wheel speed signals Driver demand - pneumatic Brake chamber Delivery pressure Reservoir pressure Axle load / bogie load ParameterTrailer ABSTrailer EBS Control Input Variables: X Driver demand - CANXX X X X X

Electronic Braking and Aid to Vehicle StabilityBradford University13 Anti-Lock control Load sensing Auxiliary Outputs Auxiliary inputs Automatic brake applications FunctionTrailer ABSTrailer EBS Functionality: Data communicationsXx x XX X X X X

Electronic Braking and Aid to Vehicle StabilityBradford University14 Roll Stability Function

Electronic Braking and Aid to Vehicle StabilityBradford University15 Objective:Objective: Reduce the Incidence of Trailer Induced Roll-Over Lateral Acceleration Sensor Roll Stability Software Trailer EBS +

Electronic Braking and Aid to Vehicle StabilityBradford University16 Tractor / Trailer Compatibility: Trailer equipped with EBS + RSF Towing VehicleTrailer Specification Functionality No ISO7638 (no ABS) No ABS - LSF - RSF ABS Full functionality EBS Full functionality EBS + ESF Full functionality Full functionality maintained when connected to any towing vehicle equipped with an ISO7638 power supply (5 or 7pin)

Electronic Braking and Aid to Vehicle StabilityBradford University17 Control Line Signal Priorities: No Brake Demand: Trailer EBS defines & controls the pressure at the brake chambers Pneumatic or Electric Control Line Signal: higher If the signal would produce a brake chamber pressure higher than the pressure defined by the trailer EBS the pressure associated with the control line signal will be generated. lower If the signal would produce a brake chamber pressure lower than the pressure defined by the trailer EBS the EBS defined pressure will be generated. This principle applies irrespective of whether the brake demand is generated by the driver or the towing vehicle ESP system

Electronic Braking and Aid to Vehicle StabilityBradford University18 Conclusions: Trailer “Roll Stability” is effective when connected to a towing vehicle via the ISO7638 connector. Compatible with all ABS, EBS & EBS+ESF towing vehicles ESP-RSF RSF Installation of ESP-RSF on the tractor or RSF on the trailer is not a replacement for good driving practice.

Electronic Braking and Aid to Vehicle StabilityBradford University19 Current System Applications: Semi-Trailers Centre Axle Trailers Full Trailers Roll Control Yaw Control Roll Control Yaw Control Roll Control Yaw Control YES Air suspension only No Not necessary YES Air suspension only YES Air suspension only No Not necessary No

Electronic Braking and Aid to Vehicle StabilityBradford University20 Towing Vehicle Specification Trailer Specification Semi-trailerCentre Axle Trailer Full Trailer Non RSF RSFESPNon RSF RSFESFNon RSF RSFESF Non ABS ABS / EBS??? EBS + ESF??? Compatibility of Mixed Combinations:

Electronic Braking and Aid to Vehicle StabilityBradford University21 GRRF Ad-Hoc Working Group Electronic Vehicle Stability Control “Trailers” 25 – 26 November 2004