Improve Braking Stability and Reducing Stopping Distance

E-scooters are a popular means of micro-mobility in an urban environment. While riding an e-scooter is quite easy after some initial practice, vehicle safety is still a critical issue documented by an increasing number of reported accidents and injuries.

A technical drawback is the inferior braking behaviour compared to other commuting vehicles that share the same roadway. Typically, stopping distances are (too) long and decelerations (too) small. To handle front and rear brakes effectively, a lot of experience is required, and only skilled riders are able to utilize the potential of both brakes in combination, and, eventually, avoid a turnover while braking hard. Low-friction road surfaces pose another demanding challenge, and preventing falling over while sliding sideways is tricky.

As a technical solution for improving the braking behaviour a new brake assist is designed and implemented on a prototype e-scooter, where:

• front and rear brakes are jointly operated with a single braking device,
• braking forces are optimally distributed between the front and rear wheels depending on the actual rider mass properties, rider standing position, and road-friction conditions,
• over-braking of one or both wheels and rear-wheel lift-off are actively prevented.

Project goals

A brake-by-wire system is developed to be most flexible in design. In addition to the above aims

• the e-scooter-rider interaction is studied,
• a road-friction estimator and
• an estimator of the mass properties of the rider, such as rider mass and location of the centre of gravity, is developed.

Figure 1: Prototype e-scooter for testing, model validation and controller design

References

Klinger, Florian, Manuel Klinger, Johannes Edelmann, and Manfred Plöchl. "Electric scooter dynamics–From a vehicle safety perspective., opens an external URL in a new window" In The IAVSD International Symposium on Dynamics of Vehicles on Roads and Tracks, pp. 1102-1112. Cham: Springer International Publishing, 2021.

Researchers

• Stefano Cavosi: his Diploma-thesis was awarded with the KFV Forschungspreis 2024
• Lorenz Klaus
• Mathias Riedl
• Manuel Vögl
• Manuel Klinger
• Johannes Edelmann

Project Funding

Internal, with friendly support from Nanotec