Experiment on a Semi－Active In－Car Crib with Joint Application of Regular and Inverted Pendulum Mechanisms Using Scale Model

Nomenclature

Ar＝ －4.50m/s2 Desired crib horizontal acceleration relative to the base，or the reference input.

孩子抱过来了。他已睡着了，睡得很香。秀容月明在他脸上亲了一口：“老天待我不薄，让我看到了妻子，看到了儿子。”

C2 ＝0.00Nms/rad Damping coefficient of the joint between Arm 1，which acts as an inverted pendulum，and Arm 2，which acts as a regular pendulum.

－D1 Friction torque of the joint between the base and Arm 1.This is the control input.

l1 ＝0.385m Length of Arm 1.

垂向第三亚段为藻类繁毓丰茂，第四亚段为藻类变弱衰退阶段。其中有藻进（砂退）—砂进（藻退）的韵律叠覆过程，叠覆频率核部少，前礁、后礁较多。矿区内礁灰岩体最厚217.04 m，最薄18.86 m，形成的礁面积13 km2，长轴方向为40°，以峰项位于矿区中部靠北。

法律程序与法律职业并称为具有重要意义的法治推动力。法律程序是行政相对人实体上的权益能否得到保障和实现的保证，它一般存在于执法过程中，包括民法、刑法和行政法等执法过程。鉴于水行政是一种行政行为，本文所要论述的法律程序仅指行政法上的正当法律程序。

M ＝0.200kg Mass of the crib including the mass of the infant.

m ＝0.500kg Mass of the joint between Arms 1and 2.

m1＝0.450kg Mass of Arm 1.

m2＝0.100kg Mass of Arm 2.

An example of the experimental result for the in－car crib moving almost freely case is shown in Figs.9（a—d）.The minimum friction torque acted on the joint connecting Arm 1and the base.

Horizontal acceleration of the crib.

For the impact control system，Balandin et al.proposed a method calculating the seatbelt tension required to maintain an acceleration of the thorax，a deformation of the thorax，and the migration length of the occupant in the cabin within the tolerance limits during a car crash for a nonlinear human－vehicle system［8］.To add to the occupant safety of a modern vehicle，a crushable zone is designed for the vehicle body，and seatbelts and air bags are installed in the cabin.In addition，the use of a child－seat is obligatory when an infant is present.However，these are passive or open－loop type systems，and do not always perform as expected owing to certain types of disturbances.Therefore，an impact control system that provides feedback regarding the condition of the crib is required to obtain a definitive result.In terms of active impact control，Wang et al.investigated an optimal control system，an H infinity control system［9］，a system using feed－forward input［10］，and a gain－scheduled control system［11］.In addition，an active knee bolster applying an impact control method for protecting the occupants from injury has been developed［12］.

θ10＝－π/6 Initial angular displacement of Arm 1.

The state equation is then arranged from this equation as follows

θ12＝－π/6 Difference between angular displacements of Arms 1and 2，that is，θ12＝θ1－θ2.

θ2 Absolute angular displacement of Arm 2.

讲武堂（1912年后，改为讲武学校，这里统称“讲武堂”）初创于1907年，开学7个月后停办，1909年中秋节复办。

0 Introduction

This study focuses on equipment used to ensure the safety of an infant in a car.To reduce the collision shock and injury risk to an infant in an in－car crib （or a child safety bed）during a car crash，it is necessary to limit the force acting on the crib to below a certain allowable value.That is to say，the impact force affecting the infant within a short period of time is changed to a smaller force that affects the infant for a longer period of time by moving the crib forward.However，the cabin space of a vehicle is limited.Therefore，the force must be maintained at a constant level.To realize this objective，we propose a semi－active in－car crib with a joint application of regular and inverted pendulum mechanisms，as shown in Fig.1.The crib is supported by Arm 2，which acts like a pendulum，and the pendulum system itself is supported by Arm 1，which acts like an inverted pendulum.Arm 2rotates at a difference of 30°with Arm 1using a simple linking mechanism.In addition，the friction torque of the joint connecting the base and Arm 1is controlled using a braking mechanism.Therefore，the proposed in－car crib is able to gradually increase the deceleration of the crib and maintain it at around the target value.In addition，our proposed system is able to save energy using a semiactive control system，which is a significant advantage for a vehicle with a limited amount of power.

Fig.1 Conceptual diagram of the in－car crib with a joint application of regular and inverted pendulum mechanisms

In this project，an in－car crib，which is a bedtype child－seat，is applied because the risk of brain damage（encephalopathy）from a decrease in arterial oxygen saturation can be reduced.In particular，abdominal compression can be avoided，which is not the case when achild car seat is used.In addition，it can also be used for neonatal infants.

However，with an in－car crib，a collision impact is directed toward the infant′s side，and the resulting motion of the body is relatively complex.For this reason，the use of a spin control system was proposed for the crib，allowing the impact to fall on the infant′s back，i.e.，the force acts perpendicularly on the crib.The author developed this control technique as an actively controlled regular pendulum－type bed for use inambulances［1］.The present study therefore focuses on the development of a crib movement system.

Many different pendulum mechanisms have been proposed for crib movement systems.In a patented design by Sawaishi［2］，a child car seat is described as a rotating seat，similar to a pendulum，which is aimed at reducing the impact on a baby pressed against the seatbelt and redirecting the force toward the seat.When a child car seat is supported in this manner，the initial deceleration acting on the seat can be reduced almost completely by moving the seat.However，this deceleration cannot be reduced further after the pendulum has rotated［3］.Therefore，regular pendulumtype in－car cribs are unsuitable when large impulsive forces are involved.In our proposed in－car crib，the deceleration of the crib can be maintained at almost a constant level during a collision，which is one of the main advantages of the proposed system.A child car seat that is rotated using electromagnets installed on the seat and base to reduce the impact forces and redirect the force toward the child′s hip has been registered as a utility model by Tamura［4］.In addition，apatent for a child car seat that is rotated to a safe position before a collision using predictive information of a vehicle crash to reduce harm to the baby was developed by Ono et al［5］.With these two systems，the child car seat is moved by an ac－tuator using power during or before a collision.In our proposed system，the rotation of the arms supporting the crib is controlled semi－actively using a braking mechanism，resulting in a reduction in the impulsive force.That is，our proposed system saves energy，which is a significant advantage for a vehicle with a limited amount of power.

An inverted pendulum－type active in－car crib was previously proposed to reduce the impulsive force acting on the crib to an allowable level during crib movement in a car crash.This crib is supported by an arm，which also acts like an inverted pendulum.In a vehicle cabin，the space for the crib movement is limited.To minimize the impulsive force in such a restricted space，the force acting on the crib must be maintained at a constant level，from the initial stage until the final collision stage.The arm is initially tilted backward because of the difficulty of movement of the inverted arm.Therefore，the deceleration of the crib can be maintained at less than the vehicle deceleration until the arm reaches an upright position.In addition，a semi－active shock control system is applied to maintain the deceleration at a constant level.Although this system is effective during a car crash with strong impulsive forces，it is not effective during a car crash with weak forces because the crib does not move［3］.

当时图灵只有23岁。他提出了一个不俗的构想，主张建构一种“通用机器”。这种机器只是一种思想实验中的装置，但它是人类历史上最具影响力的机器。图灵设想的机器，可以通过运用存在于储存器中的逻辑运算解决一切数学问题，这种机器就是“图灵机”。图灵的工作推动了一场计算与认知的实践转向。他第一个提出在计算机运行中采用逻辑代码以模拟人类的各种计算和推理过程，这成了后人设计实用计算机的思想来源，也成为当今各种计算机理论的基石。今天世界计算机科学领域的最高荣誉奖称为“图灵奖”，相当于计算机科学界的诺贝尔奖。

We also propose a semi－active control system.First，we developed a control algorithm that adjusts only the damping coefficient of the joint connecting the base and the arm acting as an inverted pendulum.We confirmed the effectiveness of the system using numerical simulations.The results indicate that the deceleration of the crib increases gradually and is maintained at around the target value of 26g when the deceleration of the base fixed on the vehicle seat is 30g.Subsequently，we developed a control algorithm that adjusts the friction torque of the joint connecting the base and the arm acting as an inverted pendulum.We also confirmed the effectiveness of the modified system through numerical simulations.The results indicate that the deceleration of the crib increases gradually and is maintained at around the target value of 25gwhen the deceleration of the base fixed on the vehicle seat is 30g［3］.We then developed a control algorithm that adjusts the friction torque of the joint connecting the base and the arm acting as an inverted pendulum，as well as the joint connecting this arm and the arm acting as a regular pendulum.We again confirmed the effectiveness of the modified system through numerical simulations.The results indicate that the deceleration of the crib increases gradually and is maintained at around the target value of 25g when the deceleration of the base fixed on the vehicle seat is 30g.The robustness of the proposed control system was also examined based on numerical simulations［6］.

On the other hand，we derived a semi－active acceleration control law for controlling the acceleration of the crib directly，but it is not required for the generation of the arm trajectory.The semi－active control system was built using a dynamic equation for the jerking of the crib.The effectiveness was confirmed using software for a multibody dynamics simulation［7］.

For this work，a semi－active control law was proposed for controlling the crib horizontal acceleration relative to the vehicle.Further，the effectiveness was investigated by model examination，and some of the results are reported.

In our systems，Arm 1，which is tilted backward and acts as an inverted pendulum，is supported by a stopper.The controlled joints are set for a large damping under normal conditions for a comfortable ride.Moreover，a forward stopper is also installed for safety.In addition，the controlled joints were designed to exhibit a large fric－tion torque as a fail－safe in case of a breakdown of the control system.

等的时间总是充满无聊，但又别无他法。常爱兰叫周小羽干活，比如刷碗，比如洗菜，周小羽是一样也不肯干的。他的成绩很差，语文勉强及格，数学也是勉强及格。所以，常爱兰经常说，你这个天杀的，你老爸好的不像坏的全像来了。

θ1 Angular displacement of Arm 1.

A semi－active impact control system，in which the actuator can be miniaturized and the power consumption can be reduced，has also been studied by the author［13］.The system utilizes an actuator for semi－active control using a braking mechanism.In addition，an active seatbelt that uses a semi－active actuator was proposed，and its effectiveness was confirmed experimentally using a model［14］.Narukawa et al.studied a knee bolster applied for semi－active impact control［15］.

Although child restraint systems with moving mechanisms are not considered in the present technical standards in Japan，this paper demonstrates the extent to which the deceleration of a crib can be reduced when both a moving mechanism and a control system are applied.

1 Semi－active Control Law

First，a semi－active control law for controlling the crib horizontal acceleration relative to the base（or the vehicle or the carriage in the model experiment）is derived using the sliding mode control theory.

1.1 Analytical model

To develop the control law，an analytical model is derived，which is shown in Fig.2.The crib and joint are assumed to be a single mass particle.In this study，Arm 2rotates at a difference of 30°from Arm 1，that is，θ12＝θ1－θ2 .In addition，the torque of the joint connecting Arm 1to the base，－D1，is only controlled using a brake mechanism.And the deceleration of the vehicle，that is，of the base is assumed to be constant because of the crushable zone installed on the vehicle body.

Fig.2 Analytical model of the proposed in－car crib with joint application of regular and inverted pendulum mechanisms

1.2 Semi－active sliding mode control law

The equation of motion for the model shown in Fig.2is derived first for applying the sliding mode control theory.Then，it is differentiated to derive the control law with acceleration feedback as follows

人文教育是以经典阅读为基础，所以，需要与当前语文教学的实际情况相结合。而小学语文主题教学的教材可以选择一些古今中外的经典文章，以此帮助学生积累大量的语文底蕴，进而帮助学生能够更好地学习语文。除此之外，在小学语文主题教学中，教师对于教学内容的选择可以在教学主题的基础上，适当选择一些课外文章，不仅能够有效帮助教师顺利地进行主题教学，还能帮助学生更好地理解教学内容，进而拓展学生的语文视野，培养学生的语文情操。对于课外文章的选择，不仅要基于教学主题，选择一些提高学生语文素养的文章，还要根据学生的性格特点、兴趣爱好等因素进行选择，从而激发学生的学习兴趣，调动学生的学习积极性。

三是持续打造适应新时代需要的专业化统战干部队伍。统一战线事务头绪多、敏感度高、社会影响大，对统战干部队伍的素质提出了更高标准和要求。党的十九大报告要求，建设高素质专业化干部队伍，注重培养专业能力、专业精神，增强干部队伍适应新时代中国特色社会主义发展要求的能力［24］。着眼新时代统一战线的战略定位，新时代统一战线工作要提高专业性、主动性、科学化水平。要加强系统规划，剖析新时代统战干部队伍专业素质的结构，持续培育一支适应统战工作专业化需要的高水平干部队伍。要加强党委统战部门干部与其他党政部门干部交流，全面提升统战干部的综合能力素质。

The effectiveness of the controller was confirmed by the numerical simulations conducted using the real－size model shown in Fig.3.Fig.4 shows the simulation result with a sinusoidal disturbance，with an amplitude of 1.00g and a frequency of 120Hz，added to the vehicle deceleration for 0.1s.Figs.4（a—e）indicate the changes in vehicle acceleration，torque of joint，which is the control input，angular displacement of Arm 1，the horizontal in－car crib acceleration，and relative horizontal in－car crib acceleration，respectively.

Fig.3 Simulation model（Adams，MSC Software）

It is confirmed that the relative crib acceleration is insensitive to the high frequency disturbance，although the absolute crib acceleration is disturbed.Therefore，stable control is expected by the proposed control law.

2 Experiment

The performance of the proposed control system was confirmed by a model experiment.In particular，the effectiveness of the controller with feedback from a short sampling period of 1ms during a short collision time was verified.

2.1 Track for small scale crash testing facility

The track is a channel with the dimensions of 600mm in width，130mm in depth，and 25min length.Twenty－seven linear induction motors（LIM）with a maximum thrust of 588Nare installed at 0.9mintervals.The speed of the carriage is controlled by changing the driving frequency of the LIM using two inverters.Here，the car－riage is decelerated by LIMs connected to the power supply in reverse instead of the concrete wall after it is accelerated for ensuring the reproducibility of the deceleration.A photograph of the track is shown in Fig.5.

Fig.4 Simulation results with the proposed control and disturbance

Fig.5 Track of the small－scale crash testing facility

2.2 Carriage for small scale crash testing facility

The lightweight carriage running on the track is fabricated using aluminum.An aluminum plate of 3mm thickness，350mm width，and 900mm length is installed under the same sized steel plate installed at the bottom of the carriage to be driven by the LIMs.The clearance between the aluminum plate and the upper surface of the LIMs is adjusted to about 4mm.The area covering the LIMs becomes almost constant by making the length of the plate 900mm，and a constant thrust is expected although the effect of the magnetic leakage at the edge of the LIMs remains.The carriage is installed with four rubber wheels for supporting the dead weight；the carriage is also installed with four small rubber wheels rotating on vertical shafts and contacting the wall of the channel in order to prevent weaving.

l2 ＝0.250m Length of Arm 2.

When an infrared ray distance measuring sensor，installed in front of and behind the LIM，detects the carriage，a solid－state relay （SSR）is switched on and electric power is supplied to the LIM.The carriage is then driven.

Fig.6 Representative results of the carriage running test

A representative example of the experiment results of the carriage running test is shown in Fig.6.Figs.6（a，b）indicate the changes in carriage velocity and acceleration，respectively.From these figures，it was confirmed that the carriage with a weight of 30kg was decelerated at－19m/s2 from the velocity of 6.5m/s after it was accelerated by this system.The carriage was decelerated immediately after it was accelerated to prevent large vibration of the carriage.Also，a little delay occurred in the acceleration result for the strong low－pass filter for smoothing sets of data.

2.3 Experimental scale model of the in－car crib

A photograph of the experimental model of the in－car crib installed on the carriage is shown in Fig.7.Arm 1is installed to resemble an inverted pendulum through the rotating joint on the carriage.The friction torque of the joint is controlled by a bicycle disk brake unit that uses two multilayer piezoelectric actuators（AE0505D16DF manufactured by NEC TOKIN Co.）arranged in series.The angular displacement is measured by a magnetic rotary encoder（JR205A2048CAF manufactured by TAIHO PRODUCT Co.，Ltd.）for the feedback control.Arm 2is installed to resemble a regular pendulum with the upper end of Arm 1through a link mechanism to keep the phase constant for the simplicity of control and to reduce the moving distance of the crib.A weight is used as the crib model and a small wireless motion recorder （MVP－RF10manufactured by MicroStone Co.）for sensing the horizontal acceleration of the crib model is installed at the lower end of Arm 2.An accelerometer module（MMA7361）is also installed on the carriage.The control input is calculated by a micro－computer（Arduino Due）and the actuators are controlled by two piezo－drivers （M－2501manufactured by MESS－TEK Co.，Ltd.）.The displacement of the carriage is measured using a laser distance meter（LDM301manufactured by JENOPTIK）.The angular displacement and the control input are transmitted to the computer by radio using digital wireless control units （WCU－C2543uDH manufactured by Keitsu Electric Co.，Ltd.）in order to record the control results.

Fig.7 Experimental scale model of the in－car crib with joint application of regular and inverted pendulum mechanisms installed on the carriage

2.4 Model experiment

A car crash was simulated by decelerating the carriage at －19m/s2.The state variables were measured in 1ms intervals and the friction torque of the joint between Arm 1and the carriage was controlled in 1ms intervals.The angular displacement of Arm 1and the control input were also transmitted to the computer by radio in 1ms intervals.The displacement of the carriage was measured in 10ms intervals by the laser distance meter.

犊牛肉的主要挥发性风味物质为酮类、醛类和醇类，其中醛类多为不饱和醛，前腿肉中的主要成分为醛类，其中庚醛、正辛醛和壬醛含量分别为19.07(106/g)、27.25(106/g)、108.10(106/g)，显著高于其他两组(p<0.05)。里脊肉中的主要成分为醇类，其中1-戊醇、1-辛烯-3-醇、2-十六烷醇含量分别为31.66(106/g)、9.85(106/g)、4.27(106/g)，显著较高(p<0.05)。后腿肉的主要成分为酮类，其中3-羟基-2-丁酮、甲基庚烯酮含量分别为32.02(106/g)、8.88(106/g)。成年牛肉的酯类和醇类数量显著较高(p<0.05)。

2.4.1 Experimental result for the fixed in－car crib case

An example of the experimental result for the fixed in－car crib case is shown in Fig.8.The joint connecting Arm 1and the base was fixed by the maximum friction torque.Figs.8（a—d）indicate the changes in carriage（cart）velocity，angular displacement of Arm 1，carriage acceleration and horizontal in－car crib acceleration，respectively.

提高高速公路工程建设质量具有重要意义，对此公路建设管理工作必须在创新驱动下积极开展创新活动，从管理思路、管理方法、技术标准等多个环节开展创新活动，积极引入新技术、新方法，从管理制度开始调整，重视科技创新工作，多种方法共同使用，以提高高速公路建设管理水平。

It is confirmed that Arm 1remained at rest from Fig.8（b），and it follows that the changes in carriage acceleration and crib acceleration are almost same from Figs.8（c，d），although the crib acceleration oscillated due to the backlash of the joints.

2.4.2 Experimental result for the in－car crib moving almost freely case

To combine the advantages of a regular pendulum－type in－car crib and an inverted pendulumtype in－car crib，we propose an in－car crib that involves the joint application of both regular and inverted pendulum mechanisms.In this system，the deceleration of the crib increases gradually，and is maintained at below the vehicle deceleration，thereby resulting in a system with advantages of both a regular pendulum mechanism and an inverted pendulum mechanism［3］.

Fig.8 Experimental results for the fixed crib case

＝19.0m/s2 Acceleration of the vehicle，i.e.，acceleration of the base.This is assumed to be a constant.

From Fig.9（b），Arm 1was moving to the front stopper and collided with it.From Fig.9（d），it is confirmed that the crib deceleration can be reduced to approximately 10m/s2 while the crib is moving，although the large deceleration occurred during the collision with the front stopper.

2.4.3 Experimental result with semi－active control

A representative example of the experimental results with the proposed semi－active control is shown in Fig.10.Figs.10（e，f）indicate the changes in the crib horizontal acceleration relative to the base，and control input，respectively.

Fig.9 Experimental results for the in－car crib moving almost freely case

The parameters in the sliding mode control law of Eq.（4）were set toα＝8andδ＝0.01in this experiment，and the reference input was set to Ar＝－4.50m/s2.

The changes in carriage velocity and crib horizontal acceleration，for the three cases，are summarized in Figs.11（a，b），respectively.The thin，solid，and thick lines indicate the experimental results for the case of the fixed crib （joint fixed），the crib moving almost freely （joint torque released），and the crib controlled（joint torque controlled），respectively.

From Fig.11（a），it is clarified that the reproducibility of the carriage deceleration is ensured.

Fig.10 Experimental results for the case where acceleration feedback control was applied

Fig.11 Experimental results summarized for the three cases

From Fig.10（e），it is clarified that the relative acceleration of the crib is mainly apositive value，this means that the crib acceleration can be reduced，although it did fluctuate，and from Fig.11（b），the oscillation of crib acceleration for the crib controlled case is suppressed as compared with the acceleration for the fixed crib case and a collision with the front stopper is avoided as compared with the result for the crib moving case.Therefore，it is concluded that crib deceleration can be reduced by the proposed control system.The average of the crib horizontal acceleration relative to the base until 0.3s，when the carriage velocity becomes zero，is－3.42m/s2.The average acceleration of the carriage until 0.3s，measured by the laser distance meter，is－22.3m/s2 and the average horizontal acceleration of the in－car crib，measured by the small wireless motion recorder，is－16.8m/s2.From these average values，it is also confirmed that the crib horizontal acceleration can be reduced from the carriage acceleration，then the proposed control system，with feedback from a short sampling period of 1ms，is effective，although the relative crib acceleration did not reach the target value.

3 Conclusions

For the in－car crib with joint application of regular and inverted pendulum mechanisms，a semi－active relative acceleration control system，which could control the horizontal in－car crib acceleration relative to the base directly，was developed using the sliding mode control theory.Further，a model experiment was conducted to confirm the effectiveness of the proposed control system with feedback from a short sampling period of 1ms.The results indicated that the crib acceleration can be reduced without a collision with the front stopper，and the effectiveness is confirmed.

Furthermore，future challenges are：improvement of the experimental scale model to keep the crib deceleration constant，the refinement of the sensing and control system，and an experiment that confirms the effectiveness of the system after the carriage stops following a collision between the carriage with a wall，using an impact attenuator.

1927年的农村调查，也折射了读书人在村民眼中的尴尬处境：“读书成本太大，出来非但没有官做，即教员位置亦粥少僧多，而况学些空架子，文不象秀才，武不象丁，手不能提篮，肩不能挑担，不事生产，要吃要用。”[21]

Acknowledgement

This work was supported by a Grant－in－Aid for Scientific Research （No.JSPS KAKENHI NJP24560279）.

鲁斯·本尼迪克特在《菊与刀》中提到，“通过一花可以看世界，透过一刀亦可以看民族。”日本人酷爱菊花，也崇尚武士道精神，生性好斗却又异常温和，崇尚武力又追求美感，这就是日本民族性格的二元性。日本民族在崇尚生命的伟大的同时，也十分欣赏死亡的悲美，作为日本国花，樱花每年盛开如花海，但是赏花的佳期却在花瓣凋零时期，他们认为那种残败凋零之美更能张扬出生命蓬勃的魅力。

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