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Session: Poster Session 1 (Even numbers)
Session starts: Thursday 26 January, 16:00
Presentation starts: 16:00

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Leila Alizadehsaravi (Delft University of Technology)
Jason Moore (Delft University of Technology)

Abstract:
A bicycle is more difficult to control at low speeds due to the vehicle's unstable low-speed dynamics. Factors such as aging, disturbances, and multi-tasking can excite instability. Together with the Royal Dutch Gazelle E-bike and Bosch eBikes system, we developed the second prototype 'balance assist system', at the Delft University of Technology. We implemented the full-state feedback control algorithm on the balance assist bicycle. We evaluated the effectiveness of the Balance assist on 18 old and 14 young cyclists in two single- and multi-task scenarios at a forward velocity between 1 to 5 m/s. In the single-task scenario, participants rode the bicycle on a 30 m straight-line track. In multi-task, in the middle of the track, they additionally performed lifting/placing one hand off/on the handlebar corresponding to the identified direction of the object at the start point following a shoulder check task. In total, participants performed 16 trials (Scenarios (2) x Balance assist on/off (2) x Disturbances on/off (2) x repetitions (2)). In half of the trials per scenario, we implemented three disturbances with random intervals through the steering motor to mimic a sudden push in single-task (0.5s) or a wind gust in multi-task (1s) disturbances. We calculated the bicycle's mean absolute roll and steering rate to investigate the effect of the balance assist system on these variables in all conditions. Balance assist improved the lateral stability, indicated by reduced mean absolute roll rate, in both scenarios and groups in the presence and absence of disturbances. Especially balance assist system imposed similar lateral stability in older to young riders in single-task cycling. Moreover, balance assist decreased the steering effort, indicated by decreased mean absolute steering rate, in single-task cycling in both age groups and the presence and absence of disturbances. When the balance assist was activated, the steering rate did not differ in multi-tasking. Overall, balance assist showed the potential to improve cyclists' stability in challenging conditions, such as multi-task cycling or being subjected to sudden disturbances. Balance assist also showed promising results in reducing the continuous steering effort, which leads to safer cycling.