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Tetsunori Haraguchi,

Tetsuya Kaneko

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Abstract

Since the concept of a Personal Mobility Vehicle (PMV) that tilts inward while turning is relatively new, there is currently a lack of theoretical considerations regarding the suspension mechanism. Therefore, this study aims to explore the theoretical relationship between suspension geometry and the pitching posture during turning in a PMV with two front wheels and one rear wheel that tilts inward during turns. Our findings suggest that a combination of a front telescopic suspension and a rear full trailing arm (swing arm) suspension is suitable for minimizing both the squatting pitching of the vehicle body during turns and the disturbances caused by changes in tread and tire camber angles during wheel strokes in the upright driving position from a static force balance perspective. From a dynamic perspective, there is no significant concern about pitching occurring even in cases where there may be a delay in active tilt angle tracking (PID) control when using the combination of front telescopic suspension and rear full trailing arm suspension. However, it is essential to note that a large sprung roll moment of inertia can still induce the squatting pitching.

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Type of the Paper: Conference Paper

A Study on Suspension Geometry for Personal Mobility Vehicles (PMVs) with Inward Tilt Mechanism

Tetsunori Haraguchi^{1,2,}*, and Tetsuya
Kaneko^{3}

^{1}Institutes of Innovation for Future Society, Nagoya
University; haraguchi@nagoya-u.jp; ORCID 0000-0003-4978-4005

^{2}College of Industrial Technology, Nihon University;
haraguchi.tetsunori@nihon-u.ac.jp

^{3}Department of Mechanical Engineering for Transportation,
Osaka Sangyo University; kaneko@ge.osaka-sandai.ac.jp

*corresponding author

Name of Editor: Jason Moore

Submitted: 17/09/2023

Accepted: 18/09/2023

Published: 19/09/2023

Citation: Haraguchi, T. & Kaneko, T. (2023). A Study on
Suspension Geometry for Personal Mobility Vehicles (PMVs) with Inward
Tilt Mechanism. The Evolving Scholar - BMD 2023, 5th Edition.

This work is licensed under a Creative Commons Attribution License
(CC-BY).

**Abstr**act:

Since the concept of a Personal Mobility Vehicle (PMV) that tilts inward while turning is relatively new, there is currently a lack of theoretical considerations regarding the suspension mechanism. Therefore, this study aims to explore the theoretical relationship between suspension geometry and the pitching posture during turning in a PMV with two front wheels and one rear wheel that tilts inward during turns. Our findings suggest that a combination of a front telescopic suspension and a rear full trailing arm (swing arm) suspension is suitable for minimizing both the squatting pitching of the vehicle body during turns and the disturbances caused by changes in tread and tire camber angles during wheel strokes in the upright driving position from a static force balance perspective. From a dynamic perspective, there is no significant concern about pitching occurring even in cases where there may be a delay in active tilt angle tracking (PID) control when using the combination of front telescopic suspension and rear full trailing arm suspension. However, it is essential to note that a large sprung roll moment of inertia can still induce the squatting pitching.

**Keywords**: Personal Mobility, Suspension Geometry,
Pitching Posture, Theoretical Considerations

**1.1. Background and Motivation**

Personal Mobility Vehicles
(PMVs) have a long history as small and highly efficient vehicles. In
recent years, a completely new narrow PMV concept has been proposed
^{(1)-(4)}, which leans inward when turning like a motorcycle to
avoid overturning. However, due to the novelty of PMVs that lean inward
during turns, there is still a limited body of prior research on such
PMVs. The authors have conducted continuous studies on the social
acceptability of PMVs (Figure 1), and the design of PMVs with two front
wheels and one rear wheel, which can actively tilt inward according to
the steering wheel angle ^{(3)-(20)}. Among them, recent efforts
have been directed towards theoretical considerations of front-wheel
steering axle configurations ^{(15)(16)(17)(19)} and suspension
geometry settings ^{(18)(20)}.

**Figure 1.** PMV with two front wheels and one rear
wheel ^{(5)(7)(8)(10)(19)(20)}

Focusing on the pitching motion of passenger cars during turning, it is known that despite the relatively long wheelbase, the roll balance axis arrangement (Figure 2) causes forward-sloping pitching. However, this tendency is not observed in general motorcycles. Moreover, on a motorcycle, the rider can cancel out the vertical input from the road surface by bending and stretching both legs, which allows for a high natural frequency of the suspension. Therefore, it is possible to set the suspension's spring constant relatively high and suppress the pitching of the vehicle despite the short wheelbase.

*RCH: Roll Center Height GCH: Gravity Center Height h: Equivalent
roll moment height*

*Subscript f*: *front r*: *rear*

**Figure 2.** Roll Center Height (*RCH*) and
Gravity Center Height (*GCH*) ^{(20)(21)}

Considering the relatively short wheelbase (*l*) of the PMV
shown in Figure 1, there is a greater concern about pitching during
turns due to the roll balance axis arrangement than in automobiles.
Additionally, unlike motorcycles, the occupants of PMVs are seated and
are directly exposed to vertical input from the road surface. It is
challenging to suppress pitching by setting the suspension spring
constant (*k*) as high as in motorcycles. Therefore, the PMV,
which tilts inward when turning, requires a suspension geometry that can
take the pitching tendency under control as a design specification.
However, there is no prior theoretical framework for the suspension
mechanism of PMV.

**1.2. Objective**

When determining the suspension configuration for future PMV development, we aim to establish not just by applying existing suspension systems, but by defining the configuration with a theoretical necessity to avoid unnecessary pitching during turning. Therefore, this paper proposes suspension requirements for taking the pitching tendency under control during cornering based on mechanistic theoretical considerations for PMVs with two front wheels and one rear wheel, which have an inward tilting mechanism.

The authors also proposed a method for setting the steering axis in order to minimize road disturbances in reference (19). In this paper as well, when suppressing pitching during turns, careful consideration is given to the suspension geometry to avoid unnecessary road disturbances. These requirements will serve as fundamental guidelines for future PMV development.

**2.1. Assumed vehicle specifications**

Table 1 presents the specifications of the PMV used in this study. To reduce vehicle pitching when driving on uneven road surfaces, it is typical to set the spring constant (wheel rate) of the front and rear suspensions in such a way that the resonant frequency of the sprung mass is lower at the front than at the rear. However, in this study, to keep things simple, the spring constants of the front and rear suspensions were set such that the sprung mass resonant frequency is similar to that of a very small passenger car and the front and rear frequency are equal.

**Table 1.** Assumed vehicle specifications
^{(20)}

Item | Unit | Value | Item | Unit | Value |
---|---|---|---|---|---|

Total length (L) |
m | 2.645 | Total mass (m) |
kg | 370 |

Total width (W) |
m | 0.880 | Front mass distribution (m)_{f} |
kg | 222 |

Total height (H) |
m | 1.445 | Rear mass distribution (m)_{r} |
kg | 148 |

Wheel base (l) |
m | 2.020 | Sprung roll inertia moment (I)_{x} |
kgm^{2} |
43.0 |

Front tread (Tr) |
m | 0.807 | Sprung pitch inertia moment (I)_{y} |
kgm^{2} |
118 |

Gravity center height (GCH) |
m | 0.358 | Front spring constant (k)_{f} |
kN/m | 7.20 |

Normalized camber stiffness (D)_{y} |
10^{-2}/deg |
1.49 | Rear spring constant (k)_{r} |
kN/m | 10.0 |

**2.2. Suspension Types**

Although, a PMV with two front wheels and one rear wheel typically has a full trailing arm (swing arm) type suspension similar to a motorcycle (Figure 3 (a)) as the rear wheel, various suspension types such as typically double wishbone type (Figure 3 (b)) and telescopic type (Figure 3 (c)) are possible as the front wheels.

**Figure 3.** Various Suspension Types
^{(1)(18)(20)}

**2.3. Simplification of a Force and Moment Balance Model for
Pitching Suppression**

To achieve pitching suppression in a Personal Mobility Vehicle (PMV),
the force balance formula related to the pitching posture of the car
body during turning involves both the front and rear suspensions.
However, in this report, we focus on comparing the balance of individual
suspension forces between the front and rear of the vehicle to suppress
pitching. Assuming no significant difference in the front and rear
center of gravity height (*GCH*), we represent the pitching
posture using separate front and rear back view models. In these models,
the vehicle mass is divided according to the front and rear load
distribution, as illustrated in Figure 4. The goal is to suppress the
difference in the amount of sinking between the front and rear of the
car body when turning. Specifically, we suppress the pitching of the PMV
by matching the sinking of front center of gravity height
(*GCH _{r}*) during turning with the sinking of rear
center of gravity height (

*g*: *gravitational acceleration F _{y}*:

*Subscript L*: *left* *R*: *right*

**Figure 4.** Force and moment balance model divided
into front and rear ^{(20)}

**3.1. Full Trailing Arm Type Rear Suspension**

Figure 5 (a) depicts a schematic view from the rear of the full trailing arm rear suspension. When the vehicle is upright, the grounding point of the tire moves up and down precisely in response to vertical input, and no unnecessary lateral force disturbance is generated from the road surface.

In Figure 5 (b), the force
equilibrium state during turning is shown. As the vehicle tilts inward,
the height of the center of gravity of the vehicle decreases by
*ΔGCH _{r}*

**Figure 5.** Rear view of the full trailing arm type
rear suspension ^{(20)}

**Figure 6.** Rear body sinking for the full trailing
arm type suspension ^{(20)}

\[\begin{array}{r} {\Delta GCH}_{r1} = \left( 1 - \cos\varphi \right)GCH\#(1) \\ \end{array}\]

\[\begin{array}{r} {\Delta GCH}_{r2} = \frac{F_{yr}\sin\varphi}{k_{r}}\cos\varphi\#(2) \\ \end{array}\]

To suppress pitching during turning, it is essential to minimize the
difference in sinking between the front and rear of the vehicle. The
sinking of rear is represented by the sum of the changes in the rear
center of gravity height (*ΔGCH _{r}*

**3.2. Double Wishbone Type Front Suspension (for
Cars)**

The double wishbone type suspension is popular in automobiles. Therefore, let's first briefly organize the double wishbone type suspension for automobiles from a fundamental perspective. The mechanical equilibrium is illustrated in Figure 7. To simplify the illustration, Figure 7 demonstrates an example where the upper and lower suspension arms are parallel and equal in length, and there is no change in the tire camber angle due to suspension movement. Additionally, to avoid unnecessary complexity, the illustration assumes no roll angle is generated during turning, which implies that the torsional rigidity of the anti-roll bar is infinite.

Figure 7 illustrates the force balance of a double wishbone type
suspension, commonly used in automobiles. In a conventional car, the
virtual suspension arm axis (the line between the tire grounding point
and the instantaneous center of the suspension) is typically angled
(*α*) to reduce the vehicle body roll. The intersection of this
axis and the vehicle center is called the roll center (RC), and its
height (*RCH _{f}*) is used as a representative value for
design. However, from the perspective of the tire grounding point
trajectory, this angle (

The suspension reaction
forces (*F ^{*}_{yfL}*,

**Figure 7.** Force balance analysis for the double
wishbone type front suspension ^{(20)}

\[m_{f}a = F_{yfL} + F_{yfR}\]

\[m_{f}g = F_{zfL} + F_{zfR}\]

\[\begin{array}{r} F_{yfL}^{*} = F_{yfL}/\cos( - \alpha)\#(2.1) \\ \end{array}\]

\[\begin{array}{r} F_{yfR}^{*} = F_{yfR}/\cos\alpha\#(2.2) \\ \end{array}\]

\[\begin{array}{r} F_{zfL}^{*} = F_{yfL}\tan( - \alpha)\#(2.3) \\ \end{array}\]

\[\begin{array}{r} F_{zfR}^{*} = F_{yfR}\tan\alpha\#(2.4) \\ \end{array}\]

*F ^{*}_{yfL}*: Left suspension reaction force

*F ^{*}_{zfL}*: Left wheel lifting force in
stroke direction

**3.3. Double Wishbone Type Front Suspension (for Inward
Tilting PMVs)**

Next, referring to the aforementioned fundamental consideration
regarding the double wishbone type suspension on automobiles, Figure 8
depicts the force balance of the double wishbone type when the PMV tilts
inward. In PMVs, inward tilt balances the rolling moment of the vehicle
body during steady turning, eliminating the need to shift the load from
the inner to the outer wheel in a steady state. However, Figure 8 shows
the case where load shift occurs from the inner to the outer wheel along
with the inward tilt, as a generalized relationship that includes the
transient state. Additionally, a small initial *α* value is
assumed, as in the case of automobiles.

During turning, the left and
right wheels tilt inward by *γ* = *φ* along with the
vehicle body. Viewing the wheels from the vehicle body, the inner wheel
strokes toward the bound direction, and the outer wheel strokes toward
the rebound direction. As depicted in Figure 8, when the upper and lower
suspension arms are equal in length (1/2 of the tread) and parallel, the
roll moment balance point (RC) does not move. The reaction forces in the
axial direction of the virtual suspension arm
(*F ^{*}_{yfL}*,

**Figure 8.** Front suspension with double wishbone type
and inward tilting mechanism ^{(20)}

\[\begin{array}{r} F_{yfL}^{*} = \frac{F_{yf\ L}\cos\varphi}{\cos\alpha\cos\varphi + \sin\alpha\sin\varphi}\#(3.1) \\ \end{array}\]

\[\begin{array}{r} F_{yfR}^{*} = \frac{F_{yfR}\cos\varphi}{\cos\alpha\cos\varphi - \sin\alpha\sin\varphi}\#(3.2) \\ \end{array}\]

\[\begin{array}{r} F_{zfL}^{*} = \frac{{- F}_{yfL}\sin\alpha}{\cos\alpha\cos\varphi + \sin\alpha\sin\varphi}\#(3.3) \\ \end{array}\]

\[\begin{array}{r} F_{zfR}^{*} = \frac{F_{yfR}\sin\alpha}{\cos\alpha\cos\varphi - \sin\alpha\sin\varphi}\#(3.4) \\ \end{array}\]

In the case of a front double
wishbone type PMV, if there is no load shift between the left and right
wheels as in steady turning shown in Figure 8, the residual forces
*F ^{*}_{zfL}* and

**Figure 9.** Squatting posture of the vehicle during
tilting ^{(20)}

As discussed in Section 3.1, when using a full trailing arm type rear wheel suspension, the vehicle body tends to sink during turning. Consequently, when combined with the double wishbone type front suspension described earlier, it becomes inevitable for the PMV to be in a squat position.

In general, it is difficult to make the actual arm length of the double wishbone suspension exactly 1/2 of the tread. Therefore, the balance point (RC) of the roll moment typically moves up and down along with the suspension stroke, as shown in Figure 10.

When the PMV tilts inward during turning, the roll moment balance
point (RC) at the inner wheel moves in the direction opposite to the
tilting angle (*φ*) by the angle *θ _{L}*, and the
reaction force angle (

The axial reaction forces
(*F ^{*}_{yfL}*,

**Figure 10.** Movement of the instantaneous center
during bound/rebound ^{(20)}

\[\begin{array}{r} F_{yfL}^{*} = \frac{F_{yf\ L}\cos\varphi}{\cos\beta_{L}\cos\varphi + \sin\beta_{L}\sin\varphi}\#(4.1) \\ \end{array}\]

\[\begin{array}{r} F_{yfR}^{*} = \frac{F_{yfR}\cos\varphi}{\cos\beta_{R}\cos\varphi - \sin\beta_{R}\sin\varphi}\#(4.2) \\ \end{array}\]

\[\begin{array}{r} F_{zfL}^{*} = \frac{{- F}_{yfL}\sin\beta_{L}}{\cos\beta_{L}\cos\varphi + \sin\beta_{L}\sin\varphi}\#(4.3) \\ \end{array}\]

\[\begin{array}{r} F_{zfR}^{*} = \frac{F_{yfR}\sin\beta_{R}}{\cos\beta_{R}\cos\varphi - \sin\beta_{R}\sin\varphi}\#(4.4) \\ \end{array}\]

\[\beta_{L} = \alpha + \theta_{L}\ \ \ \ \ \ \ \ \ \ \beta_{R} = \alpha - \theta_{R}\]

**Figure 11.** Same level of sinking as the full
trailing arm type rear suspension ^{(20)}

To achieve the same sinking as the full trailing arm type without any
unnecessary lateral disturbance, it is necessary to match the movement
of the roll moment balance point (RC) to that of the full trailing arm
type when tilted inward by setting the initial reaction force angle
(*α*) to zero. This relationship is illustrated in Figure 11.
Even if there is a load shift in both front wheels, the average sinking
value of the front is the same as that of the rear, although there is
some effect in suppressing the inward tilt.

To achieve the reaction force
angle change shown in Figure 11 in a double wishbone type suspension, it
is not easy in practice. One possible approach is to significantly
shorten the length of the upper arms as shown in Figure 12. However,
this can result in significant changes in the reaction force angle
(*α*) and camber angle due to changes in vehicle height, and it
may not be possible to avoid lateral force disturbance from the road
surface. Therefore, it may not be possible to achieve both the avoidance
of road disturbances and the suppression of squatting during cornering
with a combination of double wishbone type front suspension and full
trailing arm type rear suspension.

**Figure 12.** Arm arrangement to avoid the squatting
posture ^{(20)}

**3.4. Telescopic Type Front Suspension**

Next, let us consider the upright state of a telescopic suspension,
which is commonly used in motorcycles, for both front wheels of a PMV as
shown in Figure 13. In the telescopic type, the reaction force angle
(*α*) is always zero when the left and right wheels move up and
down in phase. However, when turning as shown in Figure 14, the reaction
force axis supporting the tire lateral force tilts with the inward tilt
of the vehicle body, similar to the rear full trailing type.

The axial reaction forces (*F ^{*}_{yfL}*,

\[\begin{array}{r} F_{yfL}^{*} = F_{yf\ L}\cos\varphi\#(5.1) \\ \end{array}\]

\[\begin{array}{r} F_{yfR}^{*} = F_{yfR}\cos\varphi\#(5.2) \\ \end{array}\]

\[\begin{array}{r} F_{zfL}^{*} = {- F}_{yfL}\sin\varphi\#(5.3) \\ \end{array}\]

\[\begin{array}{r} F_{zfR}^{*} = {- F}_{yfR}\sin\varphi\#(5.4) \\ \end{array}\]

**Figure 13.** No road disturbances in the case of a
telescopic type suspension ^{(20)}

**Figure 14.** Same level of sinking as the full
trailing arm rear suspension ^{(20)}

In a PMV that tilts inward when turning, there is no need for load
shift between the left and right wheels during steady turning
(*F _{zfL}*=

In the previous chapter, as a fundamental theoretical consideration,
we examined the vehicle's posture in a static balanced state and
demonstrated that to suppress pitching during turns, it is preferable to
use a telescopic type suspension for the front wheels. However, when
transitioning to real-world analysis, it is necessary to consider the
pitching during dynamic steering response in advance. As demonstrated in
the authors' previous investigations on dynamic characteristics
^{(5)-(10), (13)} using CarMaker from a German company IPG, it
is possible to obtain vehicle responses under dynamic conditions through
multibody dynamics analysis e.g., Carmaker instead of real vehicle
experiments. However, this is an outcome as just result and does not
lead to a theoretically derived framework.

Hence, in this chapter, building upon the results obtained in the previous chapter, we extend the static analysis to systematically organize the pitching attitudes under dynamic conditions for the combination of front wheel telescopic suspension and rear wheel full trailing arm suspension using a theoretical approach.

**4.1. Active Inward Tilt Tracking Control Model**

For PMVs equipped with
motorcycle tires, the lateral forces during turns primarily arise from
camber thrust due to the tire's camber angle with respect to the ground
(Figure 15). Assuming an extremely small tire slip angle, achieving an
active inward lean angle (*φ*) involves following a target lean
angle (*TTA*) as shown in Equation (6). An illustrative concept
of a general PID control is shown in Figure 16. In the case of general
PID control for achieving active inward lean angle tracking, the actual
lean angle (*φ*) lags significantly behind the lateral
acceleration (*a*) of the vehicle ^{(5)-(10), (13)}. Even
during steady-state turns where there is no load transfer between the
left and right wheels in a PMV, as required to balance the roll moment
caused by lateral acceleration (*a*), transiently, there is a
load transfer from the inner to the outer wheel similar to automobiles
^{(5)-(10)}. For simplicity, assuming no delay due to the body's
roll inertia moment (*I _{x}*) shown in Equation (7), the
load transfer between the left and right wheels solely depends on the
delay of the active inward tilt angle tracking (PID control) behind to
lateral acceleration (

*δ*: tire steered angle *ρ*: turning
radius *l*: wheel base

**Figure 15.** Tire steering angle and turning radius
^{(10)}

\[\begin{array}{r} TTA = \tan^{- 1}\frac{v^{2}\sin\delta}{lg}\#(6) \\ \end{array}\]

\[\begin{array}{r} I_{x}\ddot{\varphi} = F_{zfR} - F_{zfL}\#(7) \\ \end{array}\]

*TTA:* target tilt angle *v*: vehicle speed

*g*: gravitational acceleration *I _{x}*:
rolling inertia

*φ*: actual tilt angle *e*: error *u*:
output

*K _{p}* = 4000: proportional gain

**Figure 16.** PID tracking control ^{(13)}

**4.2. Preliminary Dynamic Considerations of Delay in Active
Inward Tilt Tracking Control**

As an illustrative scenario, even if the vehicle has already
responded (lateral acceleration is present), if the inward tilt angle
(*φ*) has not yet occurred, load transfer between the left and
right wheels will occur similarly to the case of an automobile described
in Section 3.2. At this point, the tilt angle (*φ*) is zero.
Consequently, as indicated in Figure 12, for telescopic suspension,
*α*=*φ*, which means the reaction angle (*α*) is
also zero. By substituting *φ*=0 into Equations (5.3) and (5.4),
*F ^{*}_{zfL}*=

\[\begin{array}{r} F_{zfL} = F_{zfR}\#(8) \\ \end{array}\]

\[\begin{array}{r} F_{y} = D_{y}F_{z}\gamma\#(9) \\ \end{array}\]

\[\begin{array}{r} F_{yfL} = F_{yfR}\#(10) \\ \end{array}\]

\[\begin{array}{r} F_{zfL}^{*} = F_{zfR}^{*}\#(11) \\ \end{array}\]

**4.3. Preliminary Dynamic Considerations on the Influence of
Roll Inertia Moment**

On the other hand, as indicated in references (5)-(10), sudden steering can lead to moments where the inner wheel lifts momentarily during a turn. An example of this phenomenon is shown in Figure 17. Vehicle specifications are given in Table 1.

*F _{z}*: vertical load, subscript

*v*=10m/s, sinusoidal steering input 0.5Hz, steering
angle=±60deg

I factor of PID control *K _{i}*=50, standard sprung
roll inertia moment

**Figure 17.** Difference in vertical load change due to
roll inertia moment ^{(8)}

This phenomenon of the inner wheel lifting is influenced by the
relationship between the body's roll inertia moment
(*I _{x}*) and the control parameters
(

When the body's roll inertia moment (*I _{x}*) is
large, even if the intended stroke of the inner and outer wheels is
achieved through tracking control, the required inward tilt angle cannot
be achieved, leading to a significant rebound of the outer wheel and
lifting of the inner wheel. As shown in Figure 17 calculated using
CarMaker, while the inner wheel is lifted and the inner wheel's ground
load remains zero in case with the largest

5. Conclusions

After considering the suspension geometry of a PMV with an inward tilting mechanism, the following conclusions were drawn to take the pitching tendency under control during turning based on the mechanistic theoretical considerations:

- The rear wheel full trailing arm type suspension has the same sinking characteristic as a motorcycle, and in order to prevent body pitching, it is necessary to provide the front suspension with the same sinking characteristic as the rear suspension.

- The front double wishbone type suspension is incompatible with sinking when turning and avoiding road disturbances during straight running caused by tread and camber changes.

- The front telescopic suspension has sinking characteristics synchronized with the rear suspension and avoids road disturbances during straight running caused by tread and camber changes, regardless of whether there is load transfer between the left and right wheels due to the delay of the tracking control (PID control) for the active inward tilt.

- However, even with the front telescopic suspension, the delay in
tilt angle due to the roll moment of inertia (*I _{x}*) of
the vehicle body can cause the squatting pitching.

These findings indicate that sinking the vehicle body during turning with the front and rear suspensions of the PMV, which tilts inward when turning like a motorcycle, can take the squatting pitching tendency under control. These requirements can serve as fundamental guidelines for future PMV development. As future works, the transient phenomena that cannot be explained by static balance through dynamic model analysis on the time axis will be also investigated.

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Submitted by17 Sep 2023

- License: CC BY
- Review type: Open Review
- Publication type: Conference Paper
- Submission date: 17 September 2023
- Publication date: 19 September 2023
- Conference: The Evolving Scholar - BMD 2023, 5th Edition

Haraguchi, T. & Kaneko, T. (2023). A Study on Suspension Geometry for Personal Mobility Vehicles (PMVs) with Inward Tilt Mechanism. The Evolving Scholar - BMD 2023, 5th Edition. https://doi.org/10.59490/6506799f4a8ec6d8f1c40fd6

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