Static and dynamic analyses of mountain bikes and their riders

摘要: Mountain biking is a globally popular sport, in which the rider uses mountain bike to ride on off-road terrain. A has either front suspension system only or full-suspension decrease external vibration resulting from terrain irregularities and increase riding comfort. Despite added comfort of bikes, there are some disadvantages because the chain-suspension interaction bobbing effect absorb rider's pedalling power lead reduction efficiency. In this study, technique for evaluating efficiency seated cycling by using engineering mechanics developed. This method also found be useful determining correct crank angle beginning downstroke that upstroke during each cycle. Next, five mathematical models rider-bike systems developed Simulink SimMechanics, including one hard-tail (HT) bike, four (FS) bikes [single pivot, four-bar-linkage horst link, faux bar, virtual pivot point (VPP)]. In systems, PID controller applied elbow prevent his upper body falling down due gravity. pedalling controller Simulink, based previous theory written Matlab. Another is used control sensing real-time moving speed applying suitable force achieve desired speed. The dynamic responses flat road surface (without bumps) rough (with investigated. The values determined include force, torque power, forward velocity, contact forces rear wheels, compressions (front fork) and (rear shock absorber), sprocket distance, chain tension vertical accelerations handlebar seats. numerical results reveal that, while surface, highest, VPP most serious. However, rough terrain, conditions more stable than bike.