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7/31/2019 T3-1 Steering Systems
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7/31/2019 T3-1 Steering Systems
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Erasmus LLP Intensive Programme
Your speaker
Mark Pecqueur
Onsiphore Pecqueur (1792 1852)
Professor at KdG University college
Independent expert on Engines and vehicles
More than 18 years active in the world of alternativefuels and drive systems
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 2
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Erasmus LLP Intensive Programme
Understeer & oversteer
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 4
7/31/2019 T3-1 Steering Systems
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Erasmus LLP Intensive Programme
Understeer & oversteer
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 5
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Erasmus LLP Intensive Programme
The perfect steering system
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 6
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Erasmus LLP Intensive Programme
The perfect steering system
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 9
If we work this out we get:
+
++
=
22
22
br
br
blrl
blrl
pQff
ff
Finaly:4
22
2 br
rlpQ
f
=
If we combine this with (d) we can calculate x:
4
2
2
2
2 br
rl
br
bl
x
f
f
f
=
r
bbr
r
bb
r
x
f
ff
f
+
=
+
=2
2
2
2
2
r
bbrx
ff
+=
4
22
This is the equation of the x
coordinate of the intersectionof straight AM and BS we cannow also calculate the ycoordinate in theintersection.
7/31/2019 T3-1 Steering Systems
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Erasmus LLP Intensive Programme
The perfect steering system
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 10
pxy =
Fill in x and P and we get:
2
2
2
b
r
l
r
bb
ry
f
f
f
+
+
=
In the end we get:
r
lby
f
=2
r
bbrx
ff
+=
4
22
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Erasmus LLP Intensive Programme
The perfect steering system
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 11
24
2lim
2
b
r
bbrx
fff
r
=
+=
02
lim =
=
r
lby
f
r
02
,bf
In a first evaluation we calculate the
coordinates x and y during straightahead driving. This means that thecurvature is than equal to: Applyingthis to the equation we get:
During this situation the intersection is:
We find this point in the middle of thefront axle of the vehicle.
The second interesting point is the point with the smallest turning circle. This is when the vehicle isturning around his rear wheel the curvature is than equal to:
2
br
f= Aplying this value into the equation for x and y we
get:b
r
bbrx f
ff
rbf
=
+=
4
2lim
2
2
lr
lby
f
rbf
=
=
2
lim
2
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Erasmus LLP Intensive Programme
Different steering principles
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 12
Turntable steering system
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E LLP I t i P
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Erasmus LLP Intensive Programme
Different steering principles
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 15
Pivot steering system
0,00
5,00
10,00
15,00
20,00
25,00
30,00
5 7 911
13
15
17
19
21
23
25
27
29
31
33
35
37
39
41
43
45
47
49
51
53
55
wheelangle()
radius (m)
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Erasm s LLP Intensi e Programme
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Erasmus LLP Intensive Programme
Different steering principles
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 17
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Erasmus LLP Intensive Programme
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Erasmus LLP Intensive Programme
Forces & Moment on the steeringangle center line.
Moments du to vertical forces
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 19
Influence of or casterFncos()
Fnsin()
Erasmus LLP Intensive Programme
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Erasmus LLP Intensive Programme
Forces & Moment on the steeringangle center line.
Moments du to vertical forces
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 20
M=Fnsin()sin()ra
offset tot increase stability
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Erasmus LLP Intensive Programme
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Erasmus LLP Intensive Programme
Forces & Moment on the steeringangle center line.
Influence of the tire deformation on the moment around the king pin
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 25
displacement from the camber offset while driving in a curve
Erasmus LLP Intensive Programme
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Erasmus LLP Intensive Programme
Properties of the steering system
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 26
wa=(wl+wr)
is=ishiss
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Erasmus LLP Intensive Programme
Properties of the steering systemstiffness of the steering system
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 28
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g
Cornering performanceStationary cornering just not drifting out of the curve
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 30
FFG
Fsrslc
+= )sin()cos(
( )FFGF nrnlc += )sin()cos(
+= )cos()sin()sin()cos( GFGF cc
rgvG
r
vmFc
=
=
22
+
=
)cos()sin()sin()cos(
22
Grg
vGG
rg
vG
The centriugal force is equal to:
+
=
1)()(
22
tgrg
vtgGrg
v
Erasmus LLP Intensive Programme
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g
Cornering performanceStationary cornering just not drifting put of the curve
)()(1
2
tgtgrg
v +=
Now we calculate the speed v:
)(1
)(2
tg
tg
rgv
+
=
rgtg
tgvg
+=
)(1
)(max
Let us suppose that we drive on a flat road we have than:
rgv =
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Cornering performanceCornering stability
Powering the Future With Zero Emission and Human Powered Vehicles Terrassa 2011 33
vv gk maxmax >
rgtg
tgrg
btgh
bhtg
+>
+
)(1
)(
2)(
2)(
Square both terms and deviding by gr:
+>
+
2
)()()(1
2
)(b
tghtgtgb
htg