Tilt Control Mechanism with Rotary Actuator and Anti-roll Bar

249QR of RTRI, Vol. 60, No. 4, Nov. 2019

Akihito KAZATO

Tilt Control Mechanism with Rotary Actuator and Anti-roll Bar

Takashi KOJIMARunning Gear Laboratory, Vehicle Structure Technology Division

This paper describes the development of a bogie equipped with a new type of tilt mecha-nism capable of providing a tilt of up to 5 degrees which is the same maximum tilt angle as the conventional bolster-type tilt mechanism, though with simpler structure. The tilt mecha-nism proposed provides the tilting forces to the carbody by adding torsional torque to the tor-sion bar on the anti-rolling device. The rotary actuator, which is inserted between the torsion bar and the arm in series, generates the torsional torque. The arms and the vertical links transmit the torque to the carbody. A bench test for simulating running on a curve and car-body tilting was conducted. The results demonstrate that it is possible to tilt the carbody with high responsiveness according to the target tilt pattern up to 5 degrees.

Keywords: carbody tilting, bogie, anti-rolling device, maintenance-free, ride comfort, motion sickness

1. Introduction

On a bogie (pendulum bogie) of the “controlled natural pendulum” type which is a carbody tilting type commonly used in Japan, a pendulum beam for tilting the vehicle body is mounted on the bogie frame via bearings such as a roller device. This means that pendulum bogies have a structure that is more complicated than ordinary bogies, resulting in more time and cost required for maintenance.

A simpler type of tilting carbody which uses air springs is used for Shinkansen trains. However, because of its structure, the maximum tilt angle is limited to approxi-mately 2°, which is smaller than that of the pendulum (5° to 6°), making it difficult to significantly reduce the excess centrifugal acceleration on a meter-gauged railway line with consecutive sharp curves. Furthermore, this type of tilting carbody structure consumes a significant amount of compressed air to extend the air springs.

This paper therefore proposes a new carbody tilting mechanism that has a simpler structure than pendulum bo-gies but is capable of producing the equivalent maximum tilt angle of pendulum bogies. In developing this mechanism, steps were also taken to try to reduce motion sickness, which must be taken into consideration for ride comfort on tilt-ing carbody vehicles. The goal was to implement the control performance that can follow the RTRI-developed “JTM pat-tern [1],” which is a carbody tilt pattern (consisting of target values of continuous carbody tilt angles) that reduces low-fre-quency lateral motion: the primary cause of motion sickness.

The configuration of the carbody tilt mechanism, the specification study by simulation, and the results of the fixed tilting test with the prototype mechanism and bogie are described below.

2. Anti-rolling device type carbody tilt mechanism

2.1 Configuration of the tilt mechanism

Figure 1 shows the proposed carbody tilt mechanism. It has a structure that applies a forced torque to the tor-

sion bar spring (1) of an ordinary anti-rolling device so that the tilting force can be applied to a carbody. A motorized ro-tary actuator (2) is used to generate the torque, for respon-siveness and compactness. The tilting force is transmitted to the carbody via the arms (3) and the vertical links (4). Since the maximum tilt angle is as large as 5°, if the air springs (5) are disposed at an ordinary lateral distance of approximately 1.6 to 2.0 m, a large vertical stroke must be allowed. It was therefore decided to make the lateral distance of the air spring narrower than in the ordinary disposition. This mechanism is a so-called “carbody tilt-ing above secondary suspension” without any pendulum beam; therefore, in a curve with cant deficiency, the lateral

Fig. 1 Proposed carbody tilt mechanism

(1) Torsion bar spring(2) Rotary actuator

(4) Vertical link(5) Air spring

(6) Centering actuator


(4) Vertical link

Push the bogie frame Pull the bogie frame

(3) Arm(5) Air spring(4) Vertical link (2) Rotary actuator

9/6 (4)の文字と線の重なりを修正しました。風戸

PAPER

250 QR of RTRI, Vol. 60, No. 4, Nov. 2019

movement of the carbody against the bogie would be large, creating the concern that ride comfort could be reduced due to the lateral motion and contact with lateral bump stops. To solve this, a centering actuator [2] (6) was added to suppress lateral movement of the carbody. In general, tilt mechanisms with high stiffness tend to transmit bogie vi-brations to the carbody; however, it provides better insula-tion against vertical vibration because of the linked struc-ture that allows vertical relative-displacement between the bogie and carbody.

2.2 Forces acting on carbody during carbody tilting

Figure 2 shows the main forces acting on the carbody when it tilts while traveling through a curve. For simplic-ity, the figure shows each force as a horizontal or vertical force on the rail surface. The forces resisting the centrifu-gal force acting on the center of gravity of the carbody are the gravity horizontal direction component force on upper surface of bogie frame, the lateral force of air springs, and the centering actuator force. Since the center of gravity of the carbody is usually at a higher position than the points of action of the air spring lateral force and the centering actuator force, an outward tilting moment acts to cause the carbody to tilt out of the curve. In contrast, the air spring vertical force and the vertical link force caused by the tor-sional stiffness of the torsion bar generate the counter mo-ment. At this time, the rotary actuator generates torque to increase the vertical link force, thereby causing the inward tilting moment (necessary for carbody tilting) to act and enabling carbody tilting. Meanwhile, since the air spring vertical force moment usually acts in the direction that al-lows the carbody to be kept horizontally, it acts as a resis-tance force to carbody tilting.

3. Study on Specifications and verification by simu-lation

3.1 Required specifications for the components

To study the required specifications for the compo-nents, the following steps were taken: First, one vehicle

model equipped with the above tilt mechanism was con-structed using the multibody dynamics simulation software SIMPACK. Second, the vehicle was run at 85 km/h (curved passing speed of a controlled natural pendulum vehicle) on a curve with a radius of 300 m and a cant of 105 mm (typical of a sharp curve on a meter-gauge railway line). The car-body tilt angle was then verified. The conditions in which a tilt angle of 5° was achieved were sought by sequentially varying three parameters: the required torque for the rota-ry actuator, the torsion stiffness of the torsion bar to trans-mit the tilting force to the carbody, and the lateral distance of the air spring that provides resistance to the tilt. The air spring used was a simple linear one. As a result, the mechanism achieved a tilt angle of 5 ° and succeeded in following the JTM pattern when the maximum torque of the rotary actuator was 3 kNm, the torsional stiffness of the torsion bar was 40 kNm/rad, and the air spring lateral distance was 1 m. Figure 3 shows a summary of the calcu-lation results of the tilt angle and the actuator generation torque in the front traveling bogie.

The items used for verification obtained from the re-sults of the analysis are shown below.

3.2 Effect of track twist on tilt control

While traveling on the transition curve, it was ob-served that the rotary actuators of the front and rear bo-gies exerted forces in opposite directions to each other due to the effect of track twisting (flatness), causing them to be in tension. Such a phenomenon not only requires a large tilting force but may also affect the vehicle running safety. This phenomenon occurred when the tilt patterns of the front and rear bogies were made identical (i.e. in phase). Although the tilt patterns of the front and rear bogies of the conventional carbody tilt vehicles were identical, it may not have appeared because neither the maximum gen-erating force nor the responsiveness of the tilting actuator were very high.

To overcome this problem, a proposal was made to im-prove followability to the track twist by advancing the tilt pattern of the rear traveling bogie, by the traveling time for the running distance between the bogie centers, with respect to the front traveling bogie [3]. Figure 4 shows the comparison of the calculation results of the leading axle outside rail wheel load for when the tilt pattern was identi-cal for both the front and rear bogies and when the com-

Fig. 2 Forces acting on a carbody running through a curve or during carbody tilting

Fig. 3 Example of simulation result of tilt angle and actu-ator-generated torque

must be allowed. It was therefore decided to make the lateral distance of the air spring narrower than in the ordinary disposition. This mechanism is a so-called "carbody tilting above secondary suspension" without any pendulum beam; therefore, in a curve with cant deficiency, the lateral movement of the carbody against the bogie would be large, creating the concern that ride comfort could be reduced due to the lateral motion and contact with lateral bump stops. To solve this, a centering actuator [2] (6) was added to suppress lateral movement of the carbody. In general, tilt mechanisms with high stiffness tend to transmit bogie vibrations to the carbody; however, it provides better insulation against vertical vibration because of the linked structure that allows vertical relative-displacement between the bogie and carbody.


Figure 2 shows the main forces acting on the carbody when it tilts while traveling through a curve. For simplicity, the figure shows each force as a horizontal or vertical force on the rail surface. The forces resisting the centrifugal force acting on the center of gravity of the carbody are the gravity horizontal direction component force on upper surface of bogie frame, the lateral force of air springs, and the centering actuator force. Since the center of gravity of the carbody is usually at a higher position than the points of action of the air spring lateral force and the centering actuator force, an outward tilting moment acts to cause the carbody to tilt out of the curve. In contrast, the air spring vertical force and the vertical link force caused by the torsional stiffness of the torsion bar generate the counter moment. At this time, the rotary actuator generates torque to increase the vertical link force, thereby causing the inward tilting moment (necessary for carbody tilting) to act and enabling carbody tilting. Meanwhile, since the air spring vertical force moment usually acts in the direction that allows the carbody to be kept horizontally, it acts as a resistance force to carbody tilting. 3. Study on Specifications and verification by simulation


To study the required specifications for the components, the following steps were taken: First, one vehicle model equipped with the above tilt mechanism was constructed using the multibody dynamics simulation software SIMPACK. Second, the vehicle was run at 85 km/h (curved passing speed of a controlled natural pendulum vehicle) on a curve with a radius of 300 m and a cant of 105 mm (typical of a sharp curve on a meter-gauge railway line). The carbody tilt angle was then verified. The conditions in which a tilt angle of 5° was achieved were sought by sequentially varying three parameters: the required torque for the rotary actuator, the torsion stiffness of the torsion bar to transmit the tilting force to the carbody, and the lateral distance of the air spring that provides resistance to the tilt. The air spring used was a simple linear one. As a result, the mechanism achieved a tilt angle of 5° and succeeded in following the JTM pattern when the maximum torque of the rotary actuator was 3 kNm, the torsional stiffness of the torsion bar was 40 kNm/rad, and the air spring lateral distance was 1 m. Figure 3 shows a summary of the calculation results of the tilt angle and the actuator generation torque in the front traveling bogie.

The items used for verification obtained from the results of the analysis are shown below. 3.2 Effect of track twist on tilt control

While traveling on the transition curve, it was observed that the rotary actuators of the front and rear bogies exerted forces in opposite directions to each other due to the effect of track twisting (flatness), causing them to be in tension. Such a phenomenon not only requires a large tilting force but may also affect the vehicle running safety. This phenomenon occurred when the tilt patterns of the front and rear bogies were made identical (i.e. in phase). Although the tilt patterns of the front and rear bogies of the conventional carbody tilt vehicles were identical, it may not have appeared because neither the maximum generating force nor the responsiveness of the tilting actuator were very high.

To overcome this problem, a proposal was made to improve followability to the track twist by advancing the tilt


Component ofcentrifugal force

Vertical link force

Carbody

Componentof gravity

Vertical link force

Air spring force

Centering actuator force

Tilting

Fig. 3 Example of simulation result of tilt

angle and actuator-generated torque

0 2 4 6 8 10 12 14 16 18-2

0

2

4

6

0 2 4 6 8 10 12 14 16 18-1

0

1

2

3

Time [s]

Carb

ody

tilt

angl

e(°

)Ac

tuat

or g

ener

atio

n to

rque

(kN

m)

TargetActual

Transition curve Transition curve

Circular curve

must be allowed. It was therefore decided to make the lateral distance of the air spring narrower than in the ordinary disposition. This mechanism is a so-called "carbody tilting above secondary suspension" without any pendulum beam; therefore, in a curve with cant deficiency, the lateral movement of the carbody against the bogie would be large, creating the concern that ride comfort could be reduced due to the lateral motion and contact with lateral bump stops. To solve this, a centering actuator [2] (6) was added to suppress lateral movement of the carbody. In general, tilt mechanisms with high stiffness tend to transmit bogie vibrations to the carbody; however, it provides better insulation against vertical vibration because of the linked structure that allows vertical relative-displacement between the bogie and carbody.


Figure 2 shows the main forces acting on the carbody when it tilts while traveling through a curve. For simplicity, the figure shows each force as a horizontal or vertical force on the rail surface. The forces resisting the centrifugal force acting on the center of gravity of the carbody are the gravity horizontal direction component force on upper surface of bogie frame, the lateral force of air springs, and the centering actuator force. Since the center of gravity of the carbody is usually at a higher position than the points of action of the air spring lateral force and the centering actuator force, an outward tilting moment acts to cause the carbody to tilt out of the curve. In contrast, the air spring vertical force and the vertical link force caused by the torsional stiffness of the torsion bar generate the counter moment. At this time, the rotary actuator generates torque to increase the vertical link force, thereby causing the inward tilting moment (necessary for carbody tilting) to act and enabling carbody tilting. Meanwhile, since the air spring vertical force moment usually acts in the direction that allows the carbody to be kept horizontally, it acts as a resistance force to carbody tilting. 3. Study on Specifications and verification by simulation


To study the required specifications for the components, the following steps were taken: First, one vehicle model equipped with the above tilt mechanism was constructed using the multibody dynamics simulation software SIMPACK. Second, the vehicle was run at 85 km/h (curved passing speed of a controlled natural pendulum vehicle) on a curve with a radius of 300 m and a cant of 105 mm (typical of a sharp curve on a meter-gauge railway line). The carbody tilt angle was then verified. The conditions in which a tilt angle of 5° was achieved were sought by sequentially varying three parameters: the required torque for the rotary actuator, the torsion stiffness of the torsion bar to transmit the tilting force to the carbody, and the lateral distance of the air spring that provides resistance to the tilt. The air spring used was a simple linear one. As a result, the mechanism achieved a tilt angle of 5° and succeeded in following the JTM pattern when the maximum torque of the rotary actuator was 3 kNm, the torsional stiffness of the torsion bar was 40 kNm/rad, and the air spring lateral distance was 1 m. Figure 3 shows a summary of the calculation results of the tilt angle and the actuator generation torque in the front traveling bogie.

The items used for verification obtained from the results of the analysis are shown below. 3.2 Effect of track twist on tilt control

While traveling on the transition curve, it was observed that the rotary actuators of the front and rear bogies exerted forces in opposite directions to each other due to the effect of track twisting (flatness), causing them to be in tension. Such a phenomenon not only requires a large tilting force but may also affect the vehicle running safety. This phenomenon occurred when the tilt patterns of the front and rear bogies were made identical (i.e. in phase). Although the tilt patterns of the front and rear bogies of the conventional carbody tilt vehicles were identical, it may not have appeared because neither the maximum generating force nor the responsiveness of the tilting actuator were very high.

To overcome this problem, a proposal was made to improve followability to the track twist by advancing the tilt


Component ofcentrifugal force

Vertical link force

Carbody

Componentof gravity

Vertical link force

Air spring force

Centering actuator force

Tilting

Fig. 3 Example of simulation result of tilt

angle and actuator-generated torque

0 2 4 6 8 10 12 14 16 18-2

0

2

4

6

0 2 4 6 8 10 12 14 16 18-1

0

1

2

3

Time [s]

Carb

ody

tilt

angl

e(°

)Ac

tuat

or g

ener

atio

n to

rque

(kN

m)

TargetActual

Transition curve Transition curve

Circular curve


mand to the rear bogie was advanced. This approach sup-pressed both the increase in wheel load on the transition curve near the entrance and the decrease in wheel load on the transition curve near the exit.

3.3 Effect of lateral deviation of carbody center-of-gravity

It was found that when the carbody center-of-gravity deviated from the center of the carbody to the lateral di-rection, a large actuator force was required to retain the carbody roll moment due to this deviation. Consequently, a load would have to be continuously applied to the rotary actuator even when running in straight sections, which is undesirable. One of possible solutions for this is to improve the roll supporting stiffness by the air springs disposed on the left and right (hereinafter “air springs roll stiffness”) as well as the tilt mechanism.

3.4 Effect of improvements on motion sickness

The followability of the carbody tilt angle was effective for matching the JTM pattern. The impact of the improve-ment on motion sickness was verified using the motion sickness dose value [4] (MSDVy). Motion sickness is gener-ally felt as a result of the cumulative action of vibrations on the human body, making it desirable to suppress the MSDVy as much as possible. Figure 5 shows a continuous waveform of short-term MSDVy obtained by running on a continuous curve, assuming an actual commercial line (each MSDVy was calculated from the lateral acceleration for a total of 20 seconds before and after). Compared to the model simulating the conventional controlled pendulum vehicle, this mechanism succeeded to reduce the short-term MSDVy to 1/3 to 1/2 and suppress it to approximately

1 m/s1.5. This is equivalent to the value obtained when a conventional limited express vehicle runs in a straight line, and suggests that this mechanism should reduce motion sickness.

4. Prototyping of Tilt Mechanism

The component parts were selected on the basis of specifications formulated through simulation and those of the test equipment used for the experiment, and a proto-type was made of the tilting mechanism.

4.1 Rotary actuator and torsion bar

After researching the market for power-operated rotary actuators, the Harmonic Drive Systems SHA65 (Fig. 6) was selected, as it was the most compact model with the larg-est torque. It contains a motor and a drive gearing speed reducer (reduction gear ratio 1:161) and has a maximum torque of 3.4 kNm. It also has a braking system that fixes the input and output shafts when not energized. In addi-tion, a prototype torsion bar was made to which the rotary actuator could be attached with a torsional stiffness of 40 kNm/rad.

4.2 Centering actuator

A centering actuator was used with compressed air as the driving source [2]. This cylinder does not require a controller or sensor because it contains a mechanical valve mechanism in the piston rod to generate a reaction force (up to approximately 10 kN) depending on the displacement. It has a dead zone near the neutral position in order to sup-press unnecessary reaction forces when a vehicle is run-ning in a straight line and has the characteristic that in the case of displacement of the carbody when it is running through a curve, a large reaction force is generated.

4.3 Air spring

Since the air spring lateral distance was set to 1 m, it was necessary to avoid interference with the center pin and thus a ready-made product with a relatively small outer diameter (effective diameter 460 mm) was selected.

5. Tilting Test with Stationary Test Equipment

5.1 Configuration of test equipment

The tilt mechanism was temporarily installed on the vi-bration load test equipment that can simulate various modes of vibration on the vehicle, and conducted the stationary tilt-

Fig. 5 Evaluation of motion sickness using short-term MSDVy

Fig. 6 Rotary actuator and torsion bar

Fig. 4 Wheel load fluctuation depression effect of the rear-bogie early tilt pattern

pattern of the rear traveling bogie, by the traveling time for the running distance between the bogie centers, with respect to the front traveling bogie.[3] Figure 4 shows the comparison of the calculation results of the leading axle outside rail wheel load for when the tilt pattern was identical for both the front and rear bogies and when the command to the rear bogie was advanced. This approach suppressed both the increase in wheel load on the transition curve near the entrance and the decrease in wheel load on the transition curve near the exit. 3. 3 Effect of lateral deviation of carbody center-of-gravity

It was found that when the carbody center-of-gravity deviated from the center of the carbody to the lateral direction, a large actuator force was required to retain the carbody roll moment due to this deviation. Consequently, a load would have to be continuously applied to the rotary actuator even when running in straight sections, which is undesirable. One of possible solutions for this is to improve the roll supporting stiffness by the air springs disposed on the left and right (hereinafter "air springs roll stiffness") as well as the tilt mechanism. 3.4 Effect of improvements on motion sickness

The followability of the carbody tilt angle was effective for matching the JTM pattern. The impact of the improvement on motion sickness was verified using the motion sickness dose value [4] (MSDVy). Motion sickness is generally felt as a result of the cumulative action of vibrations on the human body, making it desirable to suppress the MSDVy as much as possible. Figure 5 shows a continuous waveform of short-term MSDVy

obtained by running on a continuous curve, assuming an actual commercial line (each MSDVy was calculated from the lateral acceleration for a total of 20 seconds before and after). Compared to the model simulating the conventional controlled pendulum vehicle, this mechanism succeeded to reduce the short-term MSDVy to 1/3 to 1/2 and suppress it to approximately 1 m/s1.5. This is equivalent to the value obtained when a conventional limited express vehicle runs in a straight line, and suggests that this mechanism should reduce motion sickness. 4. Prototyping of Tilt Mechanism

The component parts were selected on the basis of specifications formulated through simulation and those of the test equipment used for the experiment, and a prototype was made of the tilting mechanism. 4.1 Rotary actuator and torsion bar

After researching the market for power-operated rotary actuators, the Harmonic Drive Systems SHA65 (Fig. 6) was selected, as it was the most compact model with the largest torque. It contains a motor and a drive gearing speed reducer (reduction gear ratio 1:161) and has a maximum torque of 3.4 kNm. It also has a braking system that fixes the input and output shafts when not energized. In addition, a prototype torsion bar was made to which the rotary actuator could be attached with a torsional stiffness of 40 kNm/rad. 4.2 Centering actuator

A centering actuator was used with compressed air as the driving source [2]. This cylinder does not require a controller or sensor because it contains a mechanical valve mechanism in the piston rod to generate a reaction force (up to approximately 10 kN) depending on the displacement. It has a dead zone near the neutral position in order to suppress unnecessary reaction forces when a vehicle is running in a straight line and has the characteristic that in the case of displacement of the carbody when it is running through a curve, a large reaction force is generated. 4.3 Air spring

Since the air spring lateral distance was set to 1 m, it was necessary to avoid interference with the center pin and thus a ready-made product with a relatively small outer diameter (effective diameter 460 mm) was selected. 5. Tilting Test with Stationary Test Equipment 5.1 Configuration of test equipment


Fig. 5 Evaluation of motion sickness using

short-term MSDVy

0 5 10 15 2030

40

50

60

70

Time(s)

Whe

el lo

ad (k

N)

（le

adin

g ax

le o

utsid

e ra

il）

Advancing rear bogie pattern

Identical pattern

Transition curvenear the entrance

Transition curvenear the exit

Radius of curve 300mCant 105mm

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atur

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-1)

Conventional controlled pendulum vehicle

Vehicle with proposed mechanism


Rotary actuator

Torsion bar springpattern of the rear traveling bogie, by the traveling time for the running distance between the bogie centers, with respect to the front traveling bogie.[3] Figure 4 shows the comparison of the calculation results of the leading axle outside rail wheel load for when the tilt pattern was identical for both the front and rear bogies and when the command to the rear bogie was advanced. This approach suppressed both the increase in wheel load on the transition curve near the entrance and the decrease in wheel load on the transition curve near the exit. 3. 3 Effect of lateral deviation of carbody center-of-gravity










short-term MSDVy

0 5 10 15 2030

40

50

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70

Time(s)

Whe

el lo

ad (k

N)

（le

adin

g ax

le o

utsid

e ra

il）


Identical pattern




0 20 40 60 80 100 120-5

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5×10-3

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atur

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Rotary actuator

Torsion bar spring

pattern of the rear traveling bogie, by the traveling time for the running distance between the bogie centers, with respect to the front traveling bogie.[3] Figure 4 shows the comparison of the calculation results of the leading axle outside rail wheel load for when the tilt pattern was identical for both the front and rear bogies and when the command to the rear bogie was advanced. This approach suppressed both the increase in wheel load on the transition curve near the entrance and the decrease in wheel load on the transition curve near the exit. 3. 3 Effect of lateral deviation of carbody center-of-gravity










short-term MSDVy

0 5 10 15 2030

40

50

60

70

Time(s)

Whe

el lo

ad (k

N)

（le

adin

g ax

le o

utsid

e ra

il）


Identical pattern




0 20 40 60 80 100 120-5

0

5×10-3

0 20 40 60 80 100 1200

1

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Time (s)

Shor

t-te

rmM

SDVy

(m/s

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atur

e of

trac

k (m

-1)




Rotary actuator

Torsion bar spring


ing test. Figure 7 shows the configuration of the test equip-ment. The actuator (7) simulated the excess centrifugal force acting on the carbody. Figure 8 shows the installation sta-tus of the tilt mechanism. We temporarily installed the tilt mechanism on the bogie to limit the space taken by the test equipment. The carbody mass was 12.5 tons (half a carbody).

5.2 Results

5.2.1 Followability to the tilt pattern

A simulation was performed of running through a continuous curved section. Figure 9 shows time-series re-sponse waveforms of the carbody tilt angles and the tilting forces (i.e. longitudinal forces acting on the vertical link measured by a load cell). The tilting motion was smooth in all of the various conditions that were set for the test. As in the simulation, good followability was obtained in relation to the JTM pattern.

5.2.2 Communication between the left and right air springs

Based on the results of the simulation, it was decided to give the air spring system similar roll supporting stiff-ness in consideration of the left-right imbalance of the car-body mass and the fail-safe property. However, it is consid-ered that when the vehicle tilts, the air spring roll stiffness becomes a resistance and requires a larger tilting force. To verify this disadvantage solenoid valves were provided for communication between the left and right air springs (aux-iliary air reservoir), and compared the tilting performance

Fig. 7 Configuration of the stationary test equipment

Fig. 8 Installation status of the tilt mechanism

The tilt mechanism was temporarily installed on the vibration load test equipment that can simulate various modes of vibration on the vehicle, and conducted the stationary tilting test. Figure 7 shows the configuration of the test equipment. The actuator (7) simulated the excess centrifugal force acting on the carbody. Figure 8 shows the installation status of the tilt mechanism. We temporarily installed the tilt mechanism on the bogie to limit the space taken by the test equipment. The carbody mass was 12.5 tons (half a carbody). 5.2 Results


A simulation was performed of running through a continuous curved section. Figure 9 shows time-series response waveforms of the carbody tilt angles and the tilting forces (i.e. longitudinal forces acting on the vertical link measured by a load cell). The tilting motion was smooth in all of the various conditions that were set for the test. As in the simulation, goodfollowability was obtained in relation to the JTM pattern. 5.2.2 Communication between the left and right air springs

Based on the results of the simulation, it was decided to give the air spring system similar roll supporting stiffness in consideration of the left-right imbalance of the carbody mass and the fail-safe property. However, it is considered that when

the vehicle tilts, the air spring roll stiffness becomes a resistance and requires a larger tilting force. To verify this disadvantage solenoid valves were provided for communication between the left and right air springs (auxiliary air reservoir), and compared the tilting performance when the air spring roll stiffness was lowered.

As a result of the test, no effect was found on the carbody tilt angle as shown by the blue and red curves in Fig. 9. On the other hand, a reduction in the tilting force of approximately 30% on average was observed in the circular curve when communication was made between the air springs. However, in the transition curve which includes the tilt being in the transient state, the reduction of the tilting force was only approximately 10% at maximum, and at a high tilting speed, a larger tilting force was occasionally required than in the non-communication case. It is presumed that the flow rate performance of each solenoid valve used for communication was insufficient and it took time to balance the inner pressure between the left and right air springs.

5.2.3 Effect of lateral deviation of carbody center-of-gravity

To verify the effect of the lateral deviation of the carbody center-of-gravity, the position of the deadweight loaded on the carbody was adjusted and another a tilting test was conducted when the center of gravity had been shifted 25 mm. In the conditions where the left and right air springs did not communicate, no significant difference was found in the carbody tilt angle or tilting force. This is because the air spring roll stiffness bore the moment due to lateral deviation. On the other hand, in the condition where the left and right air springs communicated, the maximum value of the tilting force increased approximately 15% compared to when there was no uneven loading, as shown by the green curve in Fig. 9 (because the rotary actuator bore the moment). There was, however, no effect on the carbody tilt angle.

5.2.4 Control failure test

Fig. 7 Configuration of the stationary test

equipment


(1)

(2)

(3)(4)

(5) (6)(7)

(1) Torsion bar (2) Rotary actuator (3) Arm (4) Vertical link (5) Air spring(6) Centering actuator (7) Actuator simulating excess centrifugal force

Torsion bar

Vertical link

Rotary actuator

Air springCenteringactuator

Fig. 9 Tilt angle and tilting force in the stationary tilting test

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ody

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)

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rce

(kN

)（

Vert

ical

link

forc

e）

Without communicationWith communicationWith communication & lateral deviation

（Grey line）JTM pattern

The maximum value with lateral deviation increased approx.15%











equipment


(1)

(2)

(3)(4)

(5) (6)(7)


Torsion bar

Vertical link

Rotary actuator



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Tilti

ng fo

rce

(kN

)（

Vert

ical

link

forc

e）




when the air spring roll stiffness was lowered.As a result of the test, no effect was found on the carbody

tilt angle as shown by the blue and red curves in Fig. 9. On the other hand, a reduction in the tilting force of approxi-mately 30% on average was observed in the circular curve when communication was made between the air springs. However, in the transition curve which includes the tilt be-ing in the transient state, the reduction of the tilting force was only approximately 10% at maximum, and at a high tilting speed, a larger tilting force was occasionally required than in the non-communication case. It is presumed that the flow rate performance of each solenoid valve used for communication was insufficient and it took time to balance the inner pressure between the left and right air springs.


To verify the effect of the lateral deviation of the car-body center-of-gravity, the position of the deadweight loaded on the carbody was adjusted and another a tilting test was conducted when the center of gravity had been shifted 25 mm. In the conditions where the left and right air springs did not communicate, no significant difference was found in the carbody tilt angle or tilting force. This is because the air spring roll stiffness bore the moment due to lateral devia-tion. On the other hand, in the condition where the left and right air springs communicated, the maximum value of the tilting force increased approximately 15% compared to when there was no uneven loading, as shown by the green curve in Fig. 9 (because the rotary actuator bore the moment). There was, however, no effect on the carbody tilt angle.


Vehicle behavior was verified when the control power was lost during tilt control. When the torque of the rotary actuator was released (with the built-in brake released as well) during tilt control, the carbody lost the roll support-ing stiffness and tilted outward due to centrifugal force (reverse tilt state). This shows that in order to make the












equipment


(1)

(2)

(3)(4)

(5) (6)(7)


Torsion bar

Vertical link

Rotary actuator



20 40 60 80 100 120

6

4

2

0

-2

-4

-6

20 40 60 80 100 120

15

10

5

0

-5

-10

-15

Time (s)

Carb

ody

tilt

angl

e (°

)

Tilti

ng fo

rce

(kN

)（

Vert

ical

link

forc

e）





mechanism fail-safe, it is necessary to quickly secure the roll supporting stiffness of the carbody when the torque and brake force of the actuator are lost.

6. For Practical Use of the Proposed Carbody Tilt Mechanism

6.1 Study on the state switching function of the car-body support device

6.1.1 System configuration

Implementing the proposed mechanism requires state switching between the co-existing carbody support devices. Figure 10 shows the proposed system configuration of the carbody support device corresponding to the proposed mechanism.

A normally open solenoid valve (hereinafter, “LV sole-noid valve”) that disables the height adjustment function of a leveling valve (hereinafter, “LV”) for an ordinary air spring vehicle between the LV and each air spring. A pipe line was then added that connected the left and right air springs (or auxiliary air reservoir) and a communication solenoid valve (hereinafter, this is called “communication solenoid valve”) between them. Table 1 lists the actions of the solenoid valves and other components on tilt control, including the other necessary switching elements.

6.1.2 Action on tilt control failure

If a failure occurs in the carbody tilt control system or its peripheral system, the tilt control must be stopped to ensure safety. Table 2 lists the actions of the solenoid valves and the behavior of the carbody responding to the

control power being lost. These actions prevent the carbody from losing the roll supporting stiffness against the bogie, and secure the fail-safe property. The carbody could, how-ever, remain fixed in a tilted state if the power is lost dur-ing tilting, for example, in a circular curve. As one of the possible measures against this, it was thought that setting the brake holding power for the time of non-energization of the rotary actuator could recover the carbody position horizontally so that the air spring vertical force by the LV height adjustment function could overcome it.

6.2 Prototyping the bogie

A study was made of the equipment components of the bogie and its layout to mount the anti-rolling device type carbody tilt mechanism using an ordinary meter-gauged bolsterless bogie as the base. A prototype of the bogie was made. Figure 11 shows the prototype bogie, which was man-ufactured with a structure that had a tilt mechanism on the carbody, taking into account the running vibration applied to the rotary actuator and the component layout of the bogie.

To implement the 1 m air spring lateral distance men-tioned above, the structure supported the air springs with a connection beam connecting the cross beams, although the air springs of a typical bolsterless bogie were disposed on the side beam or outside.

7. Tilting Test with Prototype Bogie

A stationary tilting test was conducted to evaluate the carbody tilting performance of the prototype bogie.

7.1 Test method

As shown in Fig. 12, a load frame (14.7 tons in the 1/2 vehicle condition) equivalent to a carbody was mounted on

Table 1 Actions of the solenoid valves and other compo-nents on tilt control

Component name Operating state Purpose

LV solenoid valve ClosedTo disable the vehicle height adjustment function by LV so that the tilting action will not be disturbed.

Communication solenoid valve

OpenTo reduce the roll stiffness of the air spring system, thereby reducing the resistance during tilting action.

Tilt actuator brake Brake releasedTo release the restraint of the tilt actuator to make it controllable.

Centering solenoid valve

Open To enable centering control.

Fig. 10 Proposed system configuration of the carbody support device

Vehicle behavior was verified when the control power was lost during tilt control. When the torque of the rotary actuator was released (with the built-in brake released as well) during tilt control, the carbody lost the roll supporting stiffness and tilted outward due to centrifugal force (reverse tilt state). This shows that in order to make the mechanism fail-safe, it is necessary to quickly secure the roll supporting stiffness of the carbody when the torque and brake force of the actuator are lost.


6.1 Study on the state switching function of the carbody support device



A normally open solenoid valve (hereinafter, "LV solenoid valve") that disables the height adjustment function of a leveling valve (hereinafter, “LV”) for an ordinary air spring vehicle between the LV and each air spring. A pipe line was then added that connected the left and right air springs (or auxiliary air reservoir) and a communication solenoid valve (hereinafter, this is called "communication solenoid valve") between them. Table 1 lists the actions of the solenoid valves and other components on tilt control, including the other necessary switching elements.


If a failure occurs in the carbody tilt control system or its peripheral system, the tilt control must be stopped to ensure safety. Table 2 lists the actions of the solenoid valves and the behavior of the carbody responding to the control power being lost. These actions prevent the carbody from losing the roll supporting stiffness against the bogie, and secure the fail-safe property. The carbody could, however, remain fixed in a tilted state if the power is lost during tilting, for example, in a circular curve. As one of the possible measures against this, it was thought that setting the brake holding power for the time of non-energization of the rotary actuator could recover the carbody position horizontally so that the air spring vertical force by the LV height adjustment function could overcome it.


A study was made of the equipment components of the bogie and its layout to mount the anti-rolling device type carbody tilt mechanism using an ordinary meter-gauged bolsterless bogie as the base. A prototype of the bogie was made. Figure 11 shows the prototype bogie, which was manufactured with a structure that had a tilt mechanism on the carbody, taking into account the running vibration applied to the rotary actuator and the component layout of the bogie.

To implement the 1 m air spring lateral distance mentioned above, the structure supported the air springs with a connection beam connecting the cross beams, although the air springs of a typical bolsterless bogie were disposed on the side beam or outside.


A stationary tilting test was conducted to evaluate the

Fig. 10 Proposed system configuration of the

carbody support device

Table 1 Actions of the solenoid valves and other components on tilt control

Pipe lineLV

LV solenoid valve(Normally open)

Air spring

Auxiliaryair

reservoirCommunication solenoid valve(Normally close)

Differential pressure valve

Rotary actuator (with mechanical brake)

Vertical link

Carbody

Bogie

Torsion bar

Centering actuator

Centering solenoid valve (Normally open)


LV solenoid valve Closed To disable the vehicle height adjustment function byLV so that the tilting action will not be disturbed.

Communicationsolenoid valve Open To reduce the roll stiffness of the air spring system,

thereby reducing the resistance during tilting action.

Tilt actuator brake Brake released To release the restraint of the tilt actuator to make itcontrollable.

Centering solenoidvalve Open To enable centering control.

Table 2 Actions of the solenoid valves and other components on tilt control failure

Fig. 11 Prototype bogie with anti-rolling

carbody tilting device

Component name Operating state Vehicle behavior

LV solenoid valve Open The vehicle height is adjusted by LV, and the carbodyis controlled horizontally.

Communicationsolenoid valve Closed

The left and right air springs are made independent,and the roll stiffness of the air spring system issecured.

Tilt actuator brake Brake The roll stiffness is secured by the torsion bar.

Centering solenoidvalve Closed Centering control is released.

(2) Rotary actuator

(1) Torsion bar


(4) Vertical link

(3) Arm

Fig. 11 Prototype bogie with anti-rolling carbody tilting device

Vehicle behavior was verified when the control power was lost during tilt control. When the torque of the rotary actuator was released (with the built-in brake released as well) during tilt control, the carbody lost the roll supporting stiffness and tilted outward due to centrifugal force (reverse tilt state). This shows that in order to make the mechanism fail-safe, it is necessary to quickly secure the roll supporting stiffness of the carbody when the torque and brake force of the actuator are lost.


6.1 Study on the state switching function of the carbody support device



A normally open solenoid valve (hereinafter, "LV solenoid valve") that disables the height adjustment function of a leveling valve (hereinafter, “LV”) for an ordinary air spring vehicle between the LV and each air spring. A pipe line was then added that connected the left and right air springs (or auxiliary air reservoir) and a communication solenoid valve (hereinafter, this is called "communication solenoid valve") between them. Table 1 lists the actions of the solenoid valves and other components on tilt control, including the other necessary switching elements.


If a failure occurs in the carbody tilt control system or its peripheral system, the tilt control must be stopped to ensure safety. Table 2 lists the actions of the solenoid valves and the behavior of the carbody responding to the control power being lost. These actions prevent the carbody from losing the roll supporting stiffness against the bogie, and secure the fail-safe property. The carbody could, however, remain fixed in a tilted state if the power is lost during tilting, for example, in a circular curve. As one of the possible measures against this, it was thought that setting the brake holding power for the time of non-energization of the rotary actuator could recover the carbody position horizontally so that the air spring vertical force by the LV height adjustment function could overcome it.


A study was made of the equipment components of the bogie and its layout to mount the anti-rolling device type carbody tilt mechanism using an ordinary meter-gauged bolsterless bogie as the base. A prototype of the bogie was made. Figure 11 shows the prototype bogie, which was manufactured with a structure that had a tilt mechanism on the carbody, taking into account the running vibration applied to the rotary actuator and the component layout of the bogie.

To implement the 1 m air spring lateral distance mentioned above, the structure supported the air springs with a connection beam connecting the cross beams, although the air springs of a typical bolsterless bogie were disposed on the side beam or outside.


A stationary tilting test was conducted to evaluate the

Fig. 10 Proposed system configuration of the

carbody support device

Table 1 Actions of the solenoid valves and other components on tilt control

Pipe lineLV

LV solenoid valve(Normally open)

Air spring

Auxiliaryair

reservoirCommunication solenoid valve(Normally close)

Differential pressure valve

Rotary actuator (with mechanical brake)

Vertical link

Carbody

Bogie

Torsion bar

Centering actuator

Centering solenoid valve (Normally open)


LV solenoid valve Closed To disable the vehicle height adjustment function byLV so that the tilting action will not be disturbed.

Communicationsolenoid valve Open To reduce the roll stiffness of the air spring system,

thereby reducing the resistance during tilting action.

Tilt actuator brake Brake released To release the restraint of the tilt actuator to make itcontrollable.

Centering solenoidvalve Open To enable centering control.

Table 2 Actions of the solenoid valves and other components on tilt control failure

Fig. 11 Prototype bogie with anti-rolling

carbody tilting device


LV solenoid valve Open The vehicle height is adjusted by LV, and the carbodyis controlled horizontally.

Communicationsolenoid valve Closed

The left and right air springs are made independent,and the roll stiffness of the air spring system issecured.


Centering solenoidvalve Closed Centering control is released.

(2) Rotary actuator

(1) Torsion bar


(4) Vertical link

(3) Arm

Table 2 Actions of the solenoid valves and other compo-nents on tilt control failure


LV solenoid valve OpenThe vehicle height is adjusted by LV, and the carbody is controlled horizontally.

Communication solenoid valve

ClosedThe left and right air springs are made independent, and the roll stiffness of the air spring system issecured.


Centering solenoid valve

Closed Centering control is released.


the prototype bogie. The JTM pattern simulating actual running was controlled as the target angle with various curve radii and set cant values. The excess centrifugal force generated in curves was simulated by pulling the as-sumed center-of-gravity height of the carbody laterally via a wire rope.

7.2 Results

Figure 13 shows the carbody tilt angles and actuator current values that resulted from the With- and Without-Communication conditions. Since the communication sole-noid valve used in Section 5.2.2 had an insufficient opening area, a ball valve with an opening area of about 66 mm2

was used for this test.The carbody tilt angle followed the tilt pattern with

almost no delay with or without communication. The maxi-mum tilt angle in the circular curve was larger however with communication than without. The current in the cir-cular curve exceeded the continuous rating when without communication, whereas it was reduced by 35% and was around the continuous rating with communication. The maximum current was also reduced by 33% in the transi-tion curve. The above strongly suggests that air spring communication is an effective means for reducing the tilt-ing force.

In tests where the carbody center-of-gravity was dis-placed 62 mm to the outside of the curve, the current in the circular curve exceeded the continuous rating. Consequent-ly, this reveals that necessary measures include the follow-ing: (1) design a carbody that suppresses lateral deviation of the carbody center-of-gravity as much as possible, (2) use an actuator with a margin of output in consideration of

Fig. 13 Result of the stationary tilting test on a prototype bogie

Fig. 12 Load frame and bogie at a tilt angle of 5°

carbody tilting performance of the prototype bogie.

7.1 Test method

As shown in Fig. 12, a load frame (14.7 tons in the 1/2 vehicle condition) equivalent to a carbody was mounted on the prototype bogie. The JTM pattern simulating actual running was controlled as the target angle with various curve radii and set cant values. The excess centrifugal force generated in curves was simulated by pulling the assumed center-of-gravity height of the carbody laterally via a wire rope.

7.2 Results

Figure 13 shows the carbody tilt angles and actuator current values that resulted from the With- and Without-Communication conditions. Since the communication solenoid valve used in Section 5.2.2 had an insufficient opening area, a ball valve with an opening area of about 66 mm2 was used for this test.

The carbody tilt angle followed the tilt pattern with almost no delay with or without communication. The maximum tilt angle in the circular curve was larger however with communication than without. The current in the circular curve exceeded the continuous rating when without communication, whereas it was reduced by 35% and was around the continuous rating with communication. The maximum current was also reduced by 33% in the transition curve. The above strongly suggests that air spring communication is an effective means for reducing the tilting force. In tests where the carbody center-of-gravity was displaced

62 mm to the outside of the curve, the current in the circular curve exceeded the continuous rating. Consequently, this reveals that necessary measures include the following: (1) design a carbody that suppresses lateral deviation of the carbody center-of-gravity as much as possible, (2) use an actuator with a margin of output in consideration of lateral deviation, and (3) avoid the actuator having to bear an imbalance in force in a straight section.

8. Conclusion

This paper proposes a mechanism which uses an anti-rolling device as a new carbody tilting mechanism that has a simple structure compared to a pendulum bogie and is still able to achieve the maximum tilt angle equivalent to that of a pendulum bogie. The following findings were obtained after studying the configuration of the tilt mechanism and testing the stationary tilting test using a prototype mechanism and bogie:

- A tilt equivalent to that of a pendulum bogie (5°) was achieved by setting the maximum torque of the rotary actuator to 3 kNm or more, setting the torsional stiffness of the torsion bar to approximately 40 kNm/rad, and setting the air spring lateral distance to approximately 1 m.

- The above specification enables the mechanism to achieve the followability to the JTM pattern, which requires high responsiveness; this mechanism should therefore reduce motion sickness.

- For this mechanism to be used for tilt control, track twist (flatness) in transition curves, needs to be taken into account. To this end, advancing the carbody tilt pattern input to the rear traveling bogie by traveling time for the running distance between bogie centers against the front traveling bogie, was found to be effective.

- Communication between the left and right air springs is effective in reducing the tilting force. However, the solenoid valve selected for this purpose needs to have a sufficient flow rate performance.

- The lateral deviation of the carbody center-of-gravity requires a larger tilting force. The measures required for this include the following: (1) design a carbody that suppresses

Fig. 12 Load frame and bogie at a tilt angle

of 5°

Rotary actuator Torsion bar

Wire ropeforcentrifugalforce

Load frame (Carbody mass)

Bogie

Air spring

Fig. 13 Result of the stationary tilting test on

a prototype bogie

0 5 10 15 20 25 30 35-2

0

2

4

6

時間 (s)

車体

傾斜

角 (°

)

0 5 10 15 20 25 30 35-20

0

20

40

時間 (s)

アク

チュ

エー

タ電流

(A)

With communication

Without communication

Maximum rating

Target

With communication


Continuousrating

Carb

ody

tilt a

ngle

(°)

Actu

ator

cur

rent

(A)

Time(s)

Time(s)

carbody tilting performance of the prototype bogie.

7.1 Test method

As shown in Fig. 12, a load frame (14.7 tons in the 1/2 vehicle condition) equivalent to a carbody was mounted on the prototype bogie. The JTM pattern simulating actual running was controlled as the target angle with various curve radii and set cant values. The excess centrifugal force generated in curves was simulated by pulling the assumed center-of-gravity height of the carbody laterally via a wire rope.

7.2 Results

Figure 13 shows the carbody tilt angles and actuator current values that resulted from the With- and Without-Communication conditions. Since the communication solenoid valve used in Section 5.2.2 had an insufficient opening area, a ball valve with an opening area of about 66 mm2 was used for this test.

The carbody tilt angle followed the tilt pattern with almost no delay with or without communication. The maximum tilt angle in the circular curve was larger however with communication than without. The current in the circular curve exceeded the continuous rating when without communication, whereas it was reduced by 35% and was around the continuous rating with communication. The maximum current was also reduced by 33% in the transition curve. The above strongly suggests that air spring communication is an effective means for reducing the tilting force. In tests where the carbody center-of-gravity was displaced

62 mm to the outside of the curve, the current in the circular curve exceeded the continuous rating. Consequently, this reveals that necessary measures include the following: (1) design a carbody that suppresses lateral deviation of the carbody center-of-gravity as much as possible, (2) use an actuator with a margin of output in consideration of lateral deviation, and (3) avoid the actuator having to bear an imbalance in force in a straight section.

8. Conclusion

This paper proposes a mechanism which uses an anti-rolling device as a new carbody tilting mechanism that has a simple structure compared to a pendulum bogie and is still able to achieve the maximum tilt angle equivalent to that of a pendulum bogie. The following findings were obtained after studying the configuration of the tilt mechanism and testing the stationary tilting test using a prototype mechanism and bogie:

- A tilt equivalent to that of a pendulum bogie (5°) was achieved by setting the maximum torque of the rotary actuator to 3 kNm or more, setting the torsional stiffness of the torsion bar to approximately 40 kNm/rad, and setting the air spring lateral distance to approximately 1 m.


- For this mechanism to be used for tilt control, track twist (flatness) in transition curves, needs to be taken into account. To this end, advancing the carbody tilt pattern input to the rear traveling bogie by traveling time for the running distance between bogie centers against the front traveling bogie, was found to be effective.


- The lateral deviation of the carbody center-of-gravity requires a larger tilting force. The measures required for this include the following: (1) design a carbody that suppresses

Fig. 12 Load frame and bogie at a tilt angle

of 5°

Rotary actuator Torsion bar

Wire ropeforcentrifugalforce

Load frame (Carbody mass)

Bogie

Air spring

Fig. 13 Result of the stationary tilting test on

a prototype bogie

0 5 10 15 20 25 30 35-2

0

2

4

6

時間 (s)

車体

傾斜

角 (°

)

0 5 10 15 20 25 30 35-20

0

20

40

時間 (s)

アク

チュ

エー

タ電流

(A)

With communication


Maximum rating

Target

With communication


Continuousrating

Carb

ody

tilt a

ngle

(°)

Actu

ator

cur

rent

(A)

Time(s)

Time(s)

lateral deviation, and (3) avoid the actuator having to bear an imbalance in force in a straight section. 8. Conclusion

This paper proposes a mechanism which uses an anti-rolling device as a new carbody tilting mechanism that has a simple structure compared to a pendulum bogie and is still able to achieve the maximum tilt angle equivalent to that of a pendulum bogie. The following findings were obtained after studying the configuration of the tilt mecha-nism and testing the stationary tilting test using a proto-type mechanism and bogie:

- A tilt equivalent to that of a pendulum bogie (5°) was achieved by setting the maximum torque of the ro-tary actuator to 3 kNm or more, setting the torsional stiffness of the torsion bar to approximately 40 kNm/rad, and setting the air spring lateral distance to ap-proximately 1 m.


- For this mechanism to be used for tilt control, track twist (flatness) in transition curves, needs to be tak-en into account. To this end, advancing the carbody tilt pattern input to the rear traveling bogie by trav-eling time for the running distance between bogie centers against the front traveling bogie, was found to be effective.


- The lateral deviation of the carbody center-of-gravity requires a larger tilting force. The measures required for this include the following: (1) design a carbody that suppresses lateral deviation of the carbody center-of-gravity as much as possible, (2) use an actuator with a margin of output in consideration of


Authors

　　　　　

Akihito KAZATO, Dr. Eng.Senior researcher, Running Gear Laboratory,Vehicle Structure Technology DivisionResearch Areas: Carbody Suspension System,Pneumatic Control, Ride Comfort Evaluation

　　　　　

Takashi KOJIMA, Dr. Eng.Assistant senior researcher, Running GearLaboratory, Vehicle Structure TechnologyDivisionResearch Areas: Carbody Suspension System,Condition Monitoring, Signal Processing

lateral deviation, and (3) in straight sections, provide an air spring system with carbody roll supporting stiffness, through communication between the left and right air springs.

- Even if the carbody tilt control fails due to any abnormality, the tilt mechanism must not lose its stiffness. However, since the carbody needs to be returned to a horizontal position, it is necessary to have a fail-safe mechanism that uses the automatic height adjustment function of the air spring, by us-ing an LV, for example.

Future work aims to focus on component development and fail-safe system design, in order to conduct further studies for the practical application of this carbody tilting mechanism.

References

[1] Kazato, A., Kamiyama, M., Maki, Y., Kamoshita, S. and Sasaki K., “Generating method of target tilt angle of tilting vehicle by optimization based on human fac-tors,” presented at the WCRR 2013, Sydney, Australia, 2013.

[2] Ishiguri, K., Kazato, A., Miyahara, K., Niiyama, M. and Sasaki, K., “Improvement of the Lateral Ride Comfort on Railway Vehicles by Application of Pneumatic Actu-ators for Centering,” Quarterly Report of RTRI, Vol.58, No.1, pp.14-20, 2017.

[3] Kazato, A., “Tilt Control Method of Railway Vehicle to Follow Variation in Cross Level of Track,” presented at the J-Rail 2012, Tokyo, Japan, 2012, Paper 3106(in Japanese).

[4] Suzuki, H., Shiroto, H. and Tezuka, K., “Effects of Low Frequency Vibration on Train Motion Sickness,” Quar-terly Report of RTRI, Vol.46, No.1, pp.35-39, 2005.

Tilt Control Mechanism with Rotary Actuator and Anti-roll Bar

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Transcript of Tilt Control Mechanism with Rotary Actuator and Anti-roll Bar