Development of a new type of high compact magnetorheological brake for motorcycles

Nội dung text: Development of a new type of high compact magnetorheological brake for motorcycles

1. Tuyển tập Hội nghị khoa học toàn quốc lần thứ nhất về Động lực học và Điều khiển Đà Nẵng, ngày 19-20/7/2019, tr. 289-296, DOI 10.15625/vap.2019000292 Development of a new type of high compact magneto- rheological brake for motorcycles Quoc Hung Nguyen1*, Ngoc Diep Nguyen2, Duy Tuan Le2, Duc Thang Le1, Dai Hiep Le1 1Department of Computational Engineering, Vietnamese-German University, Binh Duong, Viet Nam 2Industrial University of Ho Chi Minh City, HCM, Viet Nam *Correspondence should be addressed to Hung Q. Nguyen; hung.nq@vgu.edu.vn Abstract torque was constrained to be greater than the required This study focuses on development of a high compact magneto- value (1010 N m) while the mass was required to be rheological brake (MRB) for application in motorcycles. The smaller than that of an equivalent conventional hydraulic proposed MRB consists of a rotor with multiple trapezoidal teeth brake. Nguyen et al. [4] performed an optimal design of mating with dual trapezoidal teeth on inner face of the housing. disc-type MRBs with different configuration of multiple The teeth act at multiple magnetic poles of the brake. The gap disc and different MRF type and model considering the between the mating teeth is filled with MR fluid. In order to geometric volume and the off-state temperature generate a magnetic field for controlling braking torque, a constraints. Assadsangabi at el [5] employed GA magnetic coil is placed on each side-housing of the brake. By using multiple poles with trapezoidal shape, higher contact area optimization integrated with finite element analysis (FEA) between the rotor and the housing via MRF medium is archived to get optimal solution of conventional disc-type MRB and higher intensity of magnetic flux across the MRF is expected. (single disc) for automotive application. However, the These result in a high braking torque of the brake while its size is maximum torque was smaller than the required for still kept to be compacted, which is applicable for motorcycles. automotives. Nguyen et al. [6] proposed a hybrid MRB After an introduction about the development of MRBs in configuration for motorcycles which considered the radial automotive engineering, the configuration of the proposed MRB and axial magnetic flux in order to increase its braking is presented and its braking torque is derived based on Bingham force and simultaneously decrease its mass. Although all rheological model of MRF. The proposed MRB is then optimally abovementioned literature shows the high potential designed based on finite element analysis (FEA). Its optimized abilities of MRBs in automotive and motorcycle MRB is then manufactured and its braking performance is applications, the experimental results on examining their experimentally investigated. The MRB is then installed in a actual performance are still lacked. Recently, Nguyen et al. prototype motorcycle and the field test of this prototype motorcycle integrated with the MRB is then conducted. [7] designed a new MRB in which magnetic coils is fixed Keywords: Magneto-rheological Fluid (MRF); MR brake; on both sides of the MRB housings (in this work, it is motorcycle, optimal design. called as side-coil MRB). The optimal results showed that some disadvantages of the traditional ones such as the 1. Introduction “bottle-neck” problem of magnetic flux, the nonmagnetic In the past two decades, some studies in development bobbin are required, and the difficulties in manufacturing and application of smart brake featuring magneto- and maintenance can be eliminated or minimized by using rheological fluid (MRF) have attracted the attention of this configuration. In addition, the optimal solutions also many researchers. The applications for automotive performed that in providing the same braking torque, the vehicles or motorcycles is an interesting field in design mass of the side-coil MRB was significantly improved in MRB. Some researches on improving the performance of comparison with the conventional ones. Nevertheless, all MRB for the above applications can be listed here. Park et of abovementioned MRB configurations just consider the al. [1] investigated a magneto-rheological brake design disc which has the simple rectangular shape. Thus, in this which is operated via a sliding-mode controller. Karakoc study, the MRB with a tooth-shaped rotor is proposed. et al. [2] proposed the design considerations for building a With this tooth-shape rotor, the MRB is expected to feasible automotive MRB. More recently, Park et al have provide significantly better performance characteristics performed multidisciplinary design optimization of an than the previous ones in the literature. automotive MR brake [3]. In that research, the The remainder of the paper is displayed as follows. optimization problem was to find optimal values of a Section 2 shows the proposed multiple trapezoidal-teeth proposed objective function considering both braking MRB with two coils placed on the side housings and some torque and mass of the brake. Furthermore, the braking equations for estimating its braking torque. Section 3
2. Development of a new type of high compact magneto-rheological brake for motorcycles presents the optimal design problem and the optimization rΩ Ωsin Rl     1 (3) procedure for the proposed MRB. Results and discussions yydd are then described in section 4. Finally, some conclusions where τ is the shear stress; τy and μ0 are respectively the are performed in section 5. zero-field yield stress and the viscosity of the MRF. From Eq. (1), (2) and (3), the friction torque acting on the full 2. A multiple trapezoidal-teeth MR brake length of the incline duct can be obtained as follows: with coils placed on the side housings Lcosa / 2 TRlsind 2  1 In this section, a configuration of the MRB with a rotor 0 having multiple trapezoidal teeth and two coils placed on l 2 Ωsin Rl1 the side housing (in this research, it is called as multiple 2  Rlsin1 y d d trapezoidal-teeth MRB) is proposed. Figure 1a displays a 0 (4) typical side-coil MRB and Figure 1b presents the multiple 221 32 2  Rl11 Rlsin lsin y trapezoidal-teeth one. Each abovementioned MRB has a 3 disc (rotor) made of magnetic steel is fixed to the flange of 1Ωl 32 2233  46R11 R lsin 4 R 1 l sin l sin the shaft made by nonmagnetic steel. The disc is also 2 d covered by a stationary envelope (housing) created by From Eq. (4), the friction torque in case of cylindrical duct magnetic steel. In both two configurations, each coil is ( =0) and radial duct also called as end-face duct ( = /2) are obtained respectively as followings, which are also the placed directly on one side of the brake housing. A same as that obtained in [7] countercurrent applied to the coils generates a mutual magnetic field in order to produce the braking force. It can be seen that the profile of the rotor and the inner housings in the case of the side-coil MRB are rectangular while those in the case of the proposed MRB are featured by multiple trapezoidal teeth. This trapezoidal-teeth profile makes the increment of the contact surface between the MRF and the disc; thereby, the induced braking torque of the multiple trapezoidal-teeth side-coil MRB is expected to increase notably In Figure 2a) the stress τrθ and stress τzθ acting on MR element are illustrated . It is noted that the stress τrθ is very small compared to the stress τzθ . Therefore, the induced torque from τrθ can be neglected. In order to calculate braking torque of the multiple trapezoidal-teeth MRB, firstly an incline MRF duct as shown in Figure 2b) is considered. The friction torque of a small element of the MRF in the duct (dl) acting on the rotor can be evaluated as follows: (a) The single side-coil MRB 2 2 dT r d2 A  r d2 l R1 l sind  l (1) where r is the radius of the small MRF element with respect to the rotation axis of the MRB; R1 and R2 are respectively the radius calculated from the first end and the last end of the slope gap with respect to the rotation axis; La is the projected length of the slope gap with respect to the rotation axis; φ is the angle between the slope gap and the rotation axis; l is the length of the slope gap. In addition, for small gap size of the duct, the shear rate of MRF in the duct can be approximated as: rΩ  (2) (b) The multiple trapezoidal-teeth side-coil MRB d Figure 1: Configurations of the single and the multiple where Ω is the angular velocity of the disc. trapezoidal-teeth side-coil MRBs The rheological Bing model of MRF along the normal direction of the duct can be expressed as:
3. Quoc Hung Nguyen, Ngoc Diep Nguyen, Duy Tuan Le, Duc Thang Le, Dai Hiep Le Figure 3: The division of MRF ducts for evaluating the braking torque Based on Eqs. (4)-(6), the induced partial braking torque generated in each MRF duct can be estimated as follows: 4 EiRR i 1 i 4332  yEi TRREi  [1 ( ) ] ( i 1 i ), 23dRi 1 i 0, 2, 4,6,8,10 (7) 1 TRlRll 2( 22 sin 32 sin) Ii i i3 yIi 1 (4RRl32 6 sin  4 Rl 2233 sin  l sin  ); (8) 2 Iid i i i i 1, 3, 5, 7, 9 R TRbh 2(2)( 2 11 ) (9) cycc11 d In the above, TEi is the friction torque caused by MRF in the Ei gap, TIi is the friction torque caused by MRF in the Ii gap, Tc is the friction torque caused by MRF in the C gap, Ri is the radius of the point i in the disc profile shown in Figure 3, l is the length of the inclined gap,  is the inclined angle, h is the height of the tooth,  and  are the post- a) Ei Ei b) yield viscosity of the MRF in the Ei gap, Ii and Ii are the post-yield viscosity of the MRF in the Ii gap, c and c are Figure 2: Annular ring element of MR fluid in the slope the post-yield viscosity of the MRF in the C gap. The total duct braking torque is expressed by: TTTTTT 2( bEEE024E68 E RR4 2  TTTTTTTT)2 TRR  21[1 ( )433 ]y ( ) (5) E10IIIcs 1 I3 I5 7 9 23dR 21 (10) 2 where Ts is the lip seal friction force which can be 2 R (6) TRl 2( y ); Note: RRR12 approximately evaluated by [6] d 𝑇 𝑓 𝐿 𝑓𝐴 𝑅 (11) Fig. 3 shows the description for the division of the MRF ducts in order to estimate the total braking torque of MRB. In the above equation, Ts is the friction torque of a lip seal The total braking torque is generated into three different acting on the shaft of the MRB, fc is the friction force per kinds of the MRF ducts including the inclined gaps I1, I3, unit length of the shaft perimeter due to O-ring I5, I7 and I9, the cylindrical gap C and the radial (end-face) compression depending on the percentage of seal gaps E0, E2, E4, E6, E8, and E10. compression and the hardness of the O-ring material,Lc is the friction length of the inner face of the lip seals (shaft perimeter), fh is the O-ring friction based on the fluid pressure applying to a unit projected area of the brake shaft, Ar is the seal projected area and Rs is the shaft diameter at the sealing. It is noted that in this research a field dependent Bingham rheological model of the MRF is implemented in which the rheological properties of MRF such as the induced yield stress y, post-yield viscosity µ are approximately calculated by [8] 𝑌𝑌 𝑌 𝑌2𝑒 𝑒 (12)
4. Development of a new type of high compact magneto-rheological brake for motorcycles where Y represents for rheological parameters of MRF as study, the teeth are assumed to have the same geometry), above mentioned, SY is the saturation moment index of the height of the teeth ht, outer radius of the brake R, the the Y parameter, B is the applied magnetic density which housing thickness th and the disc thickness td are is calculated from FEA. considered as design variables. In addition, it is noted that 3. The problem of design optimization for the smaller the MRF gap size is, the greater the performance of the MRB is; however, the higher the MRBs manufacturing capacity and cost will be. Therefore, in this In this section, the optimization problem of the study, the MRF gap size is fixed at 1mm for balancing the proposed multiple trapezoidal-teeth MRB is conducted for MRB performance and its cost. In the same manner, the application in small-sized motorcycles. It is noteworthy thickness of the wall separating the coil and the MRF is that the braking torque and the mass of MRBs are two also fixed at 1mm. The shaft radius Rs is set 15mm important factors which their objectives are opposite. In considering the strength of the shaft for motorcycling detail, an MRB structure should be as small as possible in application. In this study, the optimal design of MRBs providing a required braking torque for minimizing its size considers to apply for the front wheel of the small-sized and cost [9, 10]. Therefore, in this paper, the objective of motorcycle types. In detail, the Honda Wave110cc with its the MRB optimal design is to find the lightest MRB weight of 100kg is chosen to investigate. Combined with structure which can produce a required braking torque for the passenger’s mass of 150kg and the total assumed MRB implementation in a small-sized motorcycle. Generally, mass of 10kg, it can be calculated that the total mass is the optimal design of MRBs can be expressed as approximate 260kg. The front wheel radius of the Honda Minimize Wave110cc is 0.28m and the maximum braking deceleration is set 0.8g based on considering the safe 𝑚 𝑉𝜌 𝑉 𝜌 𝑉𝜌 𝑉 𝜌 𝑉𝜌 (13) braking process of the motorcycle. In this research, the Subject to 𝑥 𝑥 𝑥 , i = 1, 2 n vehicle is assumed to cruise at 60km/h; therefore, the angular velocity of the front wheel can be approximated as 𝑇 𝑇 19π rad/s. By neglecting small frictions such as the drive- line and the tire-road ones, the required braking torque can where Vd, Vh, Vs, VMR, Vbob, and Vc are the volume of the be calculated as follows: disc, the housing, the shaft, the MRF, the bobbin and the 𝑇 𝑅𝑎𝑀 (14) coil of the brake, respectively; ρd, ρh, ρs, ρMR, ρbob and ρc are the density of the discs, the housing, the shaft, the MRF where Rw is the radius of the front wheel of the motorcycle; and the coil material, correspondingly; 𝑥 and 𝑥 are the ab is the braking deceleration of the motorcycle; M is the lower and upper bounds of the corresponding geometric total weight of the motorcycle. Based on all dimensions of MRBs; n is the number of design variables; abovementioned, the total braking torque can be Tre and Tb are respectively the required and the induced approximately 572Nm. However, the total braking torque braking torque of the MRBs for a predetermined small- is divided into 45% for the front braking system (257Nm) sized motorcycle. and 55% for the rear one (315Nm). Besides, in our 4. Results and Discussions experiment, two MRBs are utilized to create the induced braking torque; thus, the necessary braking torque for all This section shows the optimal results of all considered MRBs must be higher than 128.5Nm. abovementioned MRB and some relative discussions are Nevertheless, in this research, the required braking one is performed in detail. The magnetic components (the chosen 150Nm which is higher than the necessary one to housing and the disc) of the MRB are made by the guarantee the safety braking condition. The finite element commercial steel C45. The MRF used in this study is model using PLANE 13 element of ANSYS software as MRF132-DG and its rheological parameters as mentioned displayed in Figure 4 is utilized to solve magnetic circuit in Eq (12) are obtained by using curve fitting method from of the MRB. experimental results, which are: 𝜇 0.1𝑝𝑎∙𝑠; 𝜇 In this work, FEA integrated with optimization tool to 3.8𝑝𝑎 ∙𝑠; 1 ; ; ; s 4.5T  y0 15 pa  y 40000 pa reach the optimal solution. The method to obtain optimal 1 . The size of copper coil wires is 24-gage sty 2.9T solution of MRB using first order method with golden (diameter = 0.511mm) and its maximum working current section algorithm of ANSYS optimization tool is is around 3A. However, in this research, a current of 2.5A mentioned in several works [11, 12]. The procedures to is applied to the coil to investigate the MRB performance. achieve the optimal design parameter is illustrated in In the optimal design problem, important geometric Figure 5 dimensions of the MRBs such as the coil height hc the coil width wc, the radius of significant point R0 , R1 , R11 (in this
5. Quoc Hung Nguyen, Ngoc Diep Nguyen, Duy Tuan Le, Duc Thang Le, Dai Hiep Le (a) optimization process Figure 4: Finite element models for analyzing magnetic circuit of the MRB (b) magnetic distribution of the MRB at the optimum Figure 6: Optimal solution of the MRB Table 1: Optimal solution of the MRBs when the required torque is 150Nm Design parameter [mm] Characteristics Coil: Width wc=7.5; Height hc,=24; No. of turns: 493 Max. Torque: 150.06 Housing: Rs=30, R=68.5, [Nm] th=5, L=37 Mass: 4.8 [kg] Disc: Radius R0=32.5, Figure 5: Flowchart to obtain optimal solution of MRB R1=38, R11=63.5; Total Coil Resistance: design Thickness td= 4.0, Rc=12.6 [] Teeth height: ht=2.0 Figure 6 shows the optimal solutions of the MRBs. As MRF duct gap: 1.0 shown in the Figure 6a, with a required accuracy of 0.1%, the optimal solutions can be archived after 30 iterations. To validate the precision of all above optimal results, the At the optimum, the mass of the MRB is around 4.8kg experiments should be performed to examine their actual while the braking torque can reach up to 150Nm as performance. In this study, the prototype of the proposed constrained. The distribution of magnetic density of the MRB is manufactured based on the results which are MRB at the optimum is shown in Figure 5b. The optimal shown in Table 1. Some major parts and the assembled results are summarized in Table 1. prototype are respectively shown in Figure 7a and Figure 7b. It is reminded that, in the prototypes, firstly the coils are wound using outside bobbins. After that, the bobbins are taken off and the coils are placed directly on two both side housings of the MRBs. The assembly process is conducted by the manual method and the MRB parts are assembled and fixed by bolts.
6. Development of a new type of high compact magneto-rheological brake for motorcycles (a) Components of the MRB (b) Prototype of the MRB Figure 7: Components and prototype of the multiple trapezoidal-teeth side-coil MRB for experimental testing Figure 8a shows step response of the prototype MRB with various currents from 0A to 2.5A being applied to the coils. It is realized that the response time of the induced (a) step response (b) braking torque vs. braking torque is around 0.4s. In addition, the higher the applied current current magnitude is, the greater the average value of Figure 8: Step response of the proposed MRB torque will be. In case of the applied current is 2.5A, at steady state, the braking torque can reach up to 147Nm The MRBs are placed on both sides of the wheel and fixed which is a bit smaller than the simulated one. Figure 7b to the frame of the motorcycle by bolts. The field test is shows the simulated and steady value of the braking torque conducted as followings: The motorcycle is cruising at as functions of the applied current. It is observed that in all 60km/h, when it is passing the braking point, the braking cases, the experimental results are a bit smaller than process begins and the distance between the braking point simulated ones. The reason may come from the magnetic and the stop one will be measured. With the motorcycle lost and in accurate estimation of mechanical friction. velocity of 60km/h and the braking deceleration of 0.8g, For field test of implementation of the prototype MRB for the theory generated distance during the braking process is motorcycles, two multiple trapezoidal-teeth MRBs are approximate 17m. The results of this test are shown in installed in a front wheel of a Honda Wave110cc as shown Table 2. In this table, it can be seen that the experimental in Figure 9. braking distances in 5 independent tests are matched well with the theory value; however, the experimental results are little smaller than the theory one because the total weight of the motorcycle in the experiment is corresponding smaller than the one assumed in the theory.
7. Quoc Hung Nguyen, Ngoc Diep Nguyen, Duy Tuan Le, Duc Thang Le, Dai Hiep Le that the thermal performance of the proposed MRB is completely assured in the field test. Table 3: Experimental results of the housing temperature for the multiple trapezoidal-teeth MRB Number of Measured MRB housing measurements temperature [0C] 1st 66.4 2nd 65.6 3rd 67.2 5. Conclusions In this work, the MR brake with a rotor having multiple trapezoidal teeth and two coils placed on both side housings, which was referred as multiple trapezoidal-teeth MRB, was proposed and evaluated for the small-sized motorcycle application. Based on Bingham rheological model of the MR fluid, the braking torque of the proposed MRB was derived analytically. After that, the optimization procedure of the MRB was performed based on magnetic FEA module in ANSYS software. The optimal design problem is to obtain the lightest MRB structure while its induced braking torque is still higher than a required value which is determined analytically. Experimental works on Figure 9: The installation of two proposed MRBs into the the proposed MRB showed that the errors of the achieved front wheel of a HONDA WAVE110cc motorcycle braking torque between the analytical results and the experimental ones are just from 11% to 15%. Finally, two prototypes of the multiple trapezoidal-teeth MRB were Table 2: Experimental results of the braking distance for implemented in a front wheel of a small-sized motorcycle the multiple trapezoidal-teeth MRB and the field test of its prototype is then performed to evaluate the braking performance and the temperature Braking test Measured braking distance [m] effect of the MRBs. The field test results showed that the 1st 16.7 2nd 17.0 proposed MRBs can well implemented in motorcycles. rd 3 16.5 Acknowledgement 4th 16.2 5th 16.0 This work was supported by the Vietnam National For investigating the thermal effect in the off-state Foundation for Science and Technology Development condition of MRB, the MRB temperatures are also (NAFOSTED) under grant no. 107.01-2018.335. measured via the temperature sensor placed on the housing References of each MRB. The off-state MRB temperatures are collected after two hours continuous cruising at 60km/h. [1] E. J. Park, D. Stoikov, L. Falcao da Luz, and A. Table 3 performs three independent test results of the Suleman, “A performance evaluation of an automotive housing temperatures of the proposed MRB. It is realized magnetorheological brake design with a sliding mode controller,” Mechatronics, vol. 16, no. 7, pp. 405–416, that the average MRB housing temperatures are distributed 2006. from 65.60C to 67.20C. On the other hands, according to Nguyen et al. [4], the steady temperature of MRB can be [2] K. Karakoc, E. J. Park, and A. Suleman, “Design assumed to distribute equally in the MRB and the considerations for an automotive magnetorheological brake,” Mechatronics, vol. 18, no. 8, pp. 434–447, 2008. increment of the average MRF temperature at the end of 0 the braking process can be set Δtb = 15 C. Therefore, the [3] E. J. Park, L. F. Luz and A. Suleman, maximum average MRF temperature can be simply "Multidisciplinarydesign optimization of an automotive estimated from 80.60C to 82.20C. Its temperature is magnetorheological brake design, " Comput. Struct., no. 86, pp. 207–16, 2008 significantly smaller than the MRF-132DG maximum allowable temperature of 1300C. Thus, it can be concluded [4] Q. H. Nguyen and S. B. Choi, “Optimal design of an automotive magnetorheological brake considering
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