| Bicycle is an important part of the world transport system and is widely accepted by people for its convenience, flexibility, non-pollution, fitness, economy and easy to repair. In recent years, bicycle gets development quickly. And the human body is the most important part in a human-bicycle system. Human factors should be indeed considered in the process of design. It is extremely important to study the cyclist biomechanics in riding for optimizing bicycle design.The human-bicycle system is regarded as the research object, and the dynamics analysis of the human-bicycle system was performed based on the motion capture experiment as well as the finite element analysis of the ankle model.First of all, the experiment of cycling motion capture is the preparation for dynamic simulation. LUKOtronic motion capture system was used to collect the movement information. By adjusting the saddle height, we changed the maximal knee angles in riding and then acquired cycling motion data.The unite-modelling method was adopted to establish the dynamical model of human-bicycle system in Creo, ADAMS and Life MOD. After that, dynamics simulation of inverse and forward was performed in ADAMS. According to the simulation, the periodic distribution laws and the effect of cycling speed and cycling posture on lower limb joint forces were obtained, which involves: in the 270°~280°areas of a cycling period, the joint forces are smaller; and in the 200°~230°areas, the joint forces are bigger. The results suggest that: in fitness riding, which speed lower than 22.5 km/h(60r/min), the joint forces are the smallest when the maximal knee joint angle is 120°, while that is 130°in race riding, which speed higher than 22.5 km/h. And the result is coincident with the practice of cyclists.According to the CT slice medical images of the right ankle joint, the 3D model of ankle joint was built by Mimics, Geomagic Studio and Creo software. Then the finite element analysis of the ankle model was performed. When the speed is 18.6 km/h(50r/min) and the maximal knee joint angle is 120°in riding, the displacement of the ankle joint is smaller. The displacement of arch is bigger and the displacement of the toe and lateral is smaller in the foot model. And the stress of heel bone is bigger; the stress of toe is smaller. In the distal tibia and fibula, the main distribution areas of stress include: the front and rear articular surface of the distal tibia, malleolus medialis and lateral malleolus of the distal fibula. The analysis has guidance for the prevention and treatment of ankle injury in riding. |
