Implications of developed dimensional dataset of the standard motorcycles: Non- availability of the dimensional database (of different motorcycle models), which is essential for simulator design, is the main hindrance of developing the riding simulators. It is expected that the dimensional dataset of standard motorcycles generated from the present research would be useful for deciding the dimensions of the standard motorcycle simulator.
The dimensional data regarding the interface points (handlebar, seat and footrest) of the standard motorcycle facilitated the present researcher to develop the test-rig/simulator and perform experiments in India.
Implications of anthropometrics and ROM measurements: A generic project workflow maintains the following sequence: the project exploration stage → the project validation stage → design freeze → final data → production. A manikin (a CAD model of humans) is used in the validation and project exploration stages of the aforementioned workflow. In particular, percentile manikins (95th, 50th, and 5th percentiles) are used in the project exploration stage. Sometimes, boundary manikin approach (a multiple-percentile approach) is also used in the project validation stage (Caputo et al., 2019; Scataglini and Paul, 2019) to ensure the accommodation of anthropometric variations of the targeted user population.
As there is no anthropometric and ROM database for Indian motorcyclists, the measurements obtained in this study would be utilized for development of percentile manikins as well as boundary manikins during the motorcycle design and development process. Moreover, it could be useful in the virtual environment (CAD) analysis, where, reach, vision, clearance, and inferences, and the comfort of the newly designed motorcycle could be performed in the stage of project validation. Thus, the new or modified design of motorcycle could be easily assessed in the stage of project validation. Virtual environment evaluation would be useful for the better user-compatibility of the riders (as shown in Figure 6.1). Further, the insights from the comparative analysis of anthropometric and ROM measurements would act as the roadmap for developing comprehensive anthropometric and ROM database of Indian motorcyclists.
Figure 6. 1: Application of the anthropometrics and ROM measurement in virtual ergonomics evaluation of newly design/ re-designed motorcycle
Implications of motorcyclist’s comfort joint angles and optimum riding positions: Due to various incompatibilities in terms of human factor issues, majority of the Indian motorcyclists remain unsatisfied with their motorcycle (Sai Praveen and Ray, 2015). The present research provides immediately accessible information regarding comfortable riding posture (CRP) and optimal riding position for better design of motorcycle in India.
Moreover, it is anticipated that the motorcycle designers could adopt a similar methodology as followed in present research to address the discomfort among the motorcycle users. Due implementation of the present research findings would be helpful in improving user comfort. It will undoubtedly help to improve the design of motorcycle.
As there is no clearly defined design process for Indian motorcycles in the DHM software (RAMSIS, CATIA, Jack and Santos), the inclusion of anthropometric, ROM, and comfort joint angle dataset in the DHM software would be benefit during the design and ergonomic evaluation of motorcycles. For instance, in the RAMSIS software, it could aid through the Marco-programmed database, which would consist of mean comfort joint angle values (Sabbah and Bubb, 2008). In case CATIA V5 software (Dassault Systèmes, France), the
“.txt” file would be generated with all comfort joints angles percentiles values. Whereas, in the case of Jack and Santos software, these comfort joint angles would be manually fed during the comfort analysis of motorcycle. The mean comfort joint angle value of the present study is presented in Figure 6.2. The optimal riding position dimensions (see Figure 6.3) could be applied through the golden ratio during the motorcycle concept sketching (ideation/generation) and prototype (Chou and Hsiao, 2005).
Recommendations from the association study (chapter-5): The vital information for motorcycle design is comfortable riding position (RP) and CRP. These findings of the association study of CRP and RP with the rider’s physical characteristics (anthropometry and ROM) can be applied to decide the dimensions of interface points (handlebar, seat and footrest) of motorcycle.
I. For example, while deciding the vertical dimensions of the motorcycle (i.e., R1, R2, MR1, and H) in the design process, target population’s Body fat indicators (i.e., Triceps skinfold, Subscapular skinfold, Supraspinal skinfold, Medial calf skinfold) and Motion at Sagittal plane (i.e., flexion/extension of the neck, wrist, knee, elbow, and shoulder) have to be considered.
II. Similarly, in other instants, dimensions at transverse plane (i.e., T: the distance between the G-points on the right and left handle grips and L: the distance between the G’-points on the right and left handle grips) have to be decided based on the target population’s Body bilateral length indicator (i.e., femur breadth, humerus breadth, foot-breadth) and Upperlimb Motions at Sagittal plane (i.e., Shoulder Flexion, Shoulder Extension).
III. Dimensions at the transverse plane (i.e., T and L) and horizontal dimensions at the sagittal plane (i.e., MR2, R3, and R4) are negatively affecting the comfort joint angles of upperlimb (i.e., comfort joint angles of the neck, shoulder, arms and hand/wrist).
Thus, these riding position dimensions need to be wisely decided by the designer.
IV. Comfort joint angles of lower limbs (i.e., comfort joint angles of the knee, foot) is significantly associated with Body length indicator (i.e., Stature, crotch height, buttock extension, cervical height–sitting, shoulder-elbow length, knee height, lower leg length, shoulder-elbow length, elbow-hand length, buttock-knee length, buttock-Popliteal length, Acromion grip length, ball of foot length and hand length). As the body length indicators might be changed over decades (Pheasant, 1996), the designer must consider the most recent anthropometric database of the targeted population.
V. In line-with JASO's suggestion, the present research also highlights the higher influence of comfort hip joint angles (i.e., lower back and hip joint angles), over the other two joint angles (comfort joint angles of upper/ lower limbs) in defining the riding posture.
VI. A guideline for CRP and optimal riding position are presented in chapter 4. Although not all people will comfortable with whole range of postures as individuals. However, this will guide to develop a better motorcycle design in India.
Figure 6. 2: Suggest mean comfort joint angles in a standard motorcycle design (unit: ͦ)
Figure 6. 3: Suggested optimum riding position in a standard motorcycle design (unit: cm).
