半挂汽车列车

S , the equations of motions are given at
the both axles as follows: Side-slip :
x0 = [v, r1, r2 , p1, p2 ]T , x1 =[y,ψ1,ψ2,φ1,φ2]T
Yawing:
&1 + ur1 ) = 2 S f − S M 1 (v &2 + ur2 ) = 2 S r + S M 2 (v &1 = aS − Tb I1r &2 = −bS + Tb I2r
relations with each other. The equivalent parameters, mass M i , yawing moment of inertia inertia
v1
R1
C. G.
M 1 α y1 h1 2S f y
v2
R2
C. G.
M 2 α y2 h2 2S r
I i , rolling moment of
φ1
z
v1 Y
φ2
v v2 Tb u ψ1 2S r b S Kb Tb
δ1
r1 ψ a
u
M 1,I1 ,J1 x
δ1
r1 Kφ v Kψ v2 M 2,I2 ,J2
δ2
M 1 ,I 1 2S f X
v1
r2
M 2 ,I 2 ψ2
ψ 1 -ψ 2
r2
S
a y
b
x'
Fig.2 Equivalent vehicle model for plane motion
Keywords/ Heavy duty vehicles, Driver-vehicle system, Stability, Handling performance, Body rigidity
1.
INTRODUCTION
be disturbed extensively. Therefore, it becomes necessary to establish an objective index to evaluate the handling
K t (φ 2 -φ 1 ) z K t (φ 1 -φ 2 )
φ1
Fig.1 Equivalent model with bending and torsional rigidity
z
φ2
K b and torsional rigidity K t , and furthermore they have no
（1）
and the inputs w = [δ f , δ r ]T as follows:
&0 = A0 x0 + A M0 x 1x 1+B 0w
（2）
(7)
Here, the front and the rear tire cornering forces are assumed proportional to each slip angle of the contact area at the both axles, and 2 C f , 2 C r mean the summation of cornering stiffness of right and left tires at each axle. Consequently, the linear cornering forces yield as follows:
performance in quantitative ways
in addition to
experimental and qualitative evaluations. Furthermore it may be the same way to assess new technologies of advanced chassis systems on their effectiveness for active safety. Many studies are already continued working on several systems with the potential to make driving both safer and more comfortable. In this paper a new approach is proposed to solve this subject and confirmed by computer simulations.
Hiroshi HARADA
Kyushu Institute of Technology Matsuya-Honmachi 1-2-14, Shimonoseki-City, Japan 750-1124 Phone: 81-832-82-0374, e-mail: NHT55082@nifty.com
& 1 = −Cφ 1 p1 − ( Kφ 1 − M 1 gR1 )φ1 J1 p &1 + ur1 ) − Tt + M 1 R1 (v Rolling: (3) & φ J p C p K M gR ( ) = − − − 2 2 2 φ2 2 φ2 2 2 &2 + ur2 ) + Tt + M 2 R2 (v Where the stiffness Kφ , the damping coefficient Cφ in i i
where
（8）
a, b are the distances from the vehicle
δ f , δ r are the steer angles and ε f , ε r the roll
y and the yawing angle ψ at the
steer-coefficients. In the case of lane change driving, the lateral displacement
rolling, and the roll arm length Ri are defined around the roll axis respectively, and
S f = C f {δ Biblioteka Baidu + ε f φ f − (v + ar f ) / u} S r = C r {δ r + ε r φ r − (v − brr ) / u}
Lane change driving is analyzed for heavy duty vehicles taken the bending and torsional rigidities of the vehicle body into consideration. In addition to frequency responses and a sensitivity analysis by fixed steering, the handling performance index for a driver-vehicle system is proposed in order to evaluate lateral stability, and then applied quite effectively to evaluate each contribution of the design parameters on active safety in high speeds.
J i are defined at each axles (front i = 1 , rear
y K
M 1g
φ 1φ 1
M 2g
K
φ2 φ 2
i = 2 ), respectively. The velocities of the rigid bodies are defined by ( u , vi , ri ) in the horizontal plane and both roll
velocity axis, torsional moment lateral shear force
v1 = v + ar1
v2 = v − br2
(6)
Tt around the longitudinal axis and
Combining these equations and eliminating the force S, the equations of motions are changed to the state equation of the variables
2.
STATE EQUATIONS FOR ANALYSIS
The vehicle model shown in Fig.1 is composed of two equivalent rigid bodies at the front and rear axles, which are connected with the equivalent springs of bending rigidity
center of gravity (C.G.) to each axle. The unknown moments in Eqs.(2) and (3) are assumed to be linear relation to the yaw and roll difference angles between front and rear axles, i.e. defining the equivalent stiffness
Analysis and Evaluation of Handling Performance for Heavy Duty Vehicles
Sensitivity analysis of steering responses and a closed loop handling performance
Fig.3 Equivalent rolling models at front and rear axles
pi and roll angle φ i are given around the roll axis. Assuming bending moment Tb around the vertical
(1, 2 )
Vehicle weight reduction is now the most important requirement to save energy and transportation cost. However, in general, weight reduction often decreases vehicle rigidity and consequently influences on not only ride comfort, durability, etc. but also lateral stability, i.e. steering and handling performance. Therefore in order to compromise safety problems on highways and the weight reduction for energy saving, it becomes quite difficult to optimize many design parameters including the bending and torsional stiffness of vehicle body. It is well known that good lateral stability is quite effective to prevent traffic accidents at high speeds, especially in the case of heavy and large vehicles. If a driver loses his control unfortunately, quite serious damage on driver and vehicles will be caused and then traffic flows will