Traction Curving IAVSD 2007

Parametric Simulation Study of Traction Curving of Three Axle

Steering Bogie Designs

Scott SimsonColin Cole

Research Objective

• Problem– Adhesion in tight curves

• limited by AOA– Current passive steering bogies loose

steering control under high traction• Active Steering Traction Bogies

– Higher adhesion in tight curves – Less locomotives needed for ruling grades

Passive Steering Bogies• Yaw Relaxation Bogies: Primary suspension

with yaw stiffness relaxed

• Self Steering Bogies: end axles cross linked together, Axles yaw in opposite directions only

• Force Steered Bogies: end axles are cross linked together and linked to the bogie yaw angle.

• Articulated Bogies: steering angle of bogie axles linked to the articulation angle of vehicle bodies

• Independent Wheels: Axles with independent rotating wheels, zeros longitudinal creep forces

Locomotive Bogies

• EMD Radial, [self steering, 2, 1], – 1st patent 1987 ~ 12 years after the Scheffel– Production 1993

• Further Self Steer Patents– ABB, 1993 [self steering, 3H]– MK Rail 1996, GE Locomotive 1997, [self

steer 2,1]– Bombardier, [self steer 3, AWY 3]

EMD Radial Patents

US Patents ABB

US Patents M-K Rail

US Patent GE Locomotive

US Patents Bombardier

Traction Steering Papers

• EMD Radial [1989 IHHA]: – steering performance deteriorates with

traction• IAVSD 2005, Grassie & Elkins

– Yaw relaxation bogies– Steering performance deteriorates to rigid

bogie performance levels

Active Steering • Secondary Yaw Control

– Braghin, Bruni, Resta, VSD v44– Reduces lateral loads

• Actuated Wheelset Yaw– Goodall, Mei [many publications]– Bombardier Mechtronic bogie

• Independent Wheels• Directly Steered

3 Angles of Idealised Steering

Perfect Steering

• Goodall, Bruni & Mei (IAVSD 2005)• Minimise wheel-rail creep forces

– No longitudinal creep [pure rolling]– Equal lateral creep for all wheelsets [equal

angle of attack]• Some creep in the lateral direction is

desirable to compensate for any cant-deficiency

• Requires profile conicity sufficient for the curve

Gravitational Stiffness

• Contact angles of 10 degrees before flanging

• Ignored in linear models

Traction Ideal Steering

• Longitudinal creep are not zero– Longitudinal creep need only be +ve– Lateral creep force are not needed– Contact lateral forces to balance

acceleration

Bogie Curving Forces

Research Program

• Traction Steering Ideal• Passive Bogie Simulation• New Bogie Design• Active Bogie Simulation

Simulation• 117 tonne 6 axle Locomotive• Coupler loads• Steering movements subject to friction

damping [mu = 0.05]• Traction, 16.6% 60 kph 186 kN, 37% 416 kN• Active control delay 16 Hz input and output

filter.• Test track 600m reversing curves, • Equal amounts of tangent, transition and curve

Stability Testing

Passive Bogie, Traction SteeringWear Energy for High Rail Friction Conditions

0

3

6

9

12

15

2000 1600 1250 1000 800 600 500 400 300 220 160

Curve Radius [m]

Wea

r Ene

rgy

Rigid

YawRelaxSelfSteer -3HSelfSteer 2-1ForceSteer

Wear Energy for Low Rail Friction Conditions

0

3

6

9

12

15

2000 1600 1250 1000 800 600 500 400 300 220 160

Curve Radius [m]

Wea

r Ene

rgy Rigid

YawRelaxSelfSteer -3HSelfSteer 2-1ForceSteer

Steering at High Traction

Wheel Rail Curving Wear Energy with 37% Adhesion

010

2030

4050

6070

80

0.38 0.40 0.45 0.50

Locomotive Train Position and Rail Friction

Wea

r Ene

rgy

[MJ/

Loco

mot

ive]

Rigid

Yaw Relax

Self Steer-3HSelf Steer2-1ForceSteer

Bogie PitchingSteering

Simson Bogie Patent

• Active bogie yaw control

• Forced steered • Australian

provisional patent 2007900891

Control Methods

• Semi Active– Longitudinal Creep

Forces– Yaw Moment

difference• Full Active

– Yaw misalignment – Target yaw for track

position

Semi Active Control, Sensing Creep Forces

Semi Active and Passive Steered Bogies at High and Low Friction to Adhesion Ratio

0

20

40

60

80

100

400 m 300 m 220 m 160 m 400 m 300 m 220 m 160 mTrack Curvature

Sum

med

Wea

r En

ergy

Self Steer

ActuatedWheelset YawForce Steer

Active Yaw-Force SteerRigid

Full Active Control, Sensing Yaw Alignment of Bogies

Full Active and Passive Steered Bogies for High and Low Friction Adhesion Ratio's

0

20

40

60

80

100

400m

300m

220m

160m

400m

300m

220m

160m

Curve Radius

Sum

med

W

ear E

nerg

y Self Steer

ActuatedWheelset YawForce Steer

Active Yaw-Force SteerRigid Bogie

Ideal Steeringcontrol

High Traction Curving Actuated Bogies

Wheel Rail Curving Wear Energy with 37% Adhesion

0

20

40

60

80

0.38 0.40 0.45 0.50

Locomotive Train Position and Rail Friction

Wea

r Ene

rgy

[MJ/

Loco

mot

ive]

Rigid

Self Steer 2-1

ActuatedWheelset YawForce Steer

Active Yaw -Force SteerIdeal Steer

Curvature Estimation• Active Yaw Dampers

– Braghin F., Bruni S., Resta F., (2006) VSD 44 • Curve Radius Estimate from:

– Bogie yaw velocity transducers – Vehicle speed

• Trail simulations have problems identifying curve transition vs instability– Increased wear energy in transition– Target yaw in transition to be developed

Sensor, Actuator Placement

• Actuated Wheelset Yaw– Actuators and sensors at primary

suspension• Actuated Yaw, Force Steered (Simson)

– Actuators at secondary suspension– Sensors bogie frame mounted or higher

Conclusions

• Traction steering requires ideal steering– Steering angle control– Bogie yaw angle control– Minimal or zero angle of attack

• Simson bogie – yaw activated force steered – achieves better (ideal) steering even at low friction to adhesion ratios.– Steering bogies must trade of transition

curving performance against stability