Biomechatronic and Human-Machine Control Section, Biomechanical Engineering Department, Faculty of Mechanical, Maritime, and Materials Engineering, Delft University of Technology, Delft, South Holland, The Netherlands.
PeerJ. 2023 Oct 17;11:e16206. doi: 10.7717/peerj.16206. eCollection 2023.
Bicycles are more difficult to control at low speeds due to the vehicle's unstable low-speed dynamics. This issue might be exacerbated by factors such as aging, disturbances, and multi-tasking. To address this issue, we developed a prototype 'balance assist system' with Royal Dutch Gazelle and Bosch eBike Systems at Delft University of Technology, which includes an electric motor capable of providing additional steering torque. We implemented a speed-adaptive feedback controller to generate the additional steering torque to that of the rider. We conducted a study with 18 older and 14 younger cyclists to first examine the effect of aging, disturbances, and multi-tasking on cycling at lower forward speeds, and evaluate the effectiveness of the system in improving the stability of the rider-bicycle system while facing these challenges. The study consisted of two scenarios: a single-task scenario where participants rode the bicycle on a marked narrow straight-line track, and a multi-task scenario where participants performed a shoulder check task and followed visual cues while tracking the straight-line. We introduced handlebar disturbances using the steer motor in half of the trials in both scenarios. All trials were repeated with and without the balance assist system. We calculated the bicycle mean magnitude of roll and steering rate-as indicators of bicycle balance control and required steering actions, respectively-and the rider's mean magnitude of lean rate with respect to the ground to investigate the effect of the balance assist system on rider's lateral motion. Our results showed that aging, disturbances, and multi-tasking increased the roll rate, and the balance assist system was able to significantly reduce it. The effect size of the balance assist system in reducing the roll rate across all conditions was found to be larger in older cyclists, indicating a more substantial impact compared to younger cyclists. Disturbances and multi-tasking increased the steering rate, which was successfully reduced by the balance assist system. Aging did not significantly affect the steering rate. The rider's lean rate was not significantly affected by age, disturbances, or the balance assist, indicating that the upper body plays a minor role when riders have good steering control authority. Overall, our findings suggest that lateral motion and required steering action can be affected by age, multi-tasking, and handlebar disturbances which can endanger cyclists' safety, and the balance assist system has the potential to improve cycling safety and reduce the incidence of single-actor crashes. Further investigation on riders' contribution to control actions is required.
自行车在低速时更难控制，因为车辆的低速动力学不稳定。这种情况可能会因老化、干扰和多任务等因素而加剧。为了解决这个问题，我们与荷兰皇家 Gazelle 和博世 ebike Systems 在代尔夫特理工大学合作开发了一个原型“平衡辅助系统”，其中包括一个能够提供额外转向扭矩的电动机。我们实现了一个速度自适应反馈控制器，以生成额外的转向扭矩，以配合骑手的转向。我们进行了一项研究，共有 18 名老年和 14 名年轻的自行车手参加，首先研究了老化、干扰和多任务对低速前进时骑自行车的影响，并评估了该系统在面对这些挑战时提高骑手-自行车系统稳定性的有效性。该研究包括两个场景：一个是参与者在标记的狭窄直线路径上骑自行车的单任务场景，另一个是参与者在执行肩部检查任务并跟随视觉提示的同时跟踪直线的多任务场景。我们在两个场景的一半试验中使用转向电机引入把手干扰。所有试验都在有和没有平衡辅助系统的情况下重复进行。我们计算了自行车的滚动幅度和转向率的平均值，分别作为自行车平衡控制和所需转向动作的指标，以及骑手相对于地面的倾斜率的平均值，以研究平衡辅助系统对骑手横向运动的影响。我们的结果表明，老化、干扰和多任务会增加滚动率，而平衡辅助系统能够显著降低滚动率。在所有条件下，平衡辅助系统降低滚动率的效果大小在老年自行车手身上更为显著，表明与年轻自行车手相比，影响更大。干扰和多任务增加了转向率，平衡辅助系统成功地降低了转向率。老化对转向率没有显著影响。骑手的倾斜率不受年龄、干扰或平衡辅助的影响，这表明当骑手具有良好的转向控制能力时，上半身的作用较小。总的来说，我们的研究结果表明，侧向运动和所需的转向动作可能会受到年龄、多任务和把手干扰的影响，这可能会危及自行车手的安全，平衡辅助系统有可能提高骑行安全性并减少单人事故的发生。需要进一步研究骑手对控制动作的贡献。
