Robot cycle
​Testing the robot bicycle.  Photo: Chalmers​​​​​

Robot bicycle makes traffic safer for cyclists

A self-driving bicycle, developed by students and researchers at Chalmers, can make the traffic environment safer for future cyclists.
No, it's not about us letting go of the handlebars to be able to spend the bike ride reading a book or studying bird life. The purpose of the autonomous bike is to make the future vehicle more intelligent.

Vehicles shall discover cyclists
It will help the automotive industry engineers develop new systems that allow vehicles to automatically detect cyclists and predict their behaviour. And in the long run, to react completely on its own - for example, emergency braking. All to reduce the risk of traffic accidents between a vehicle and a bicycle.

The background is that new vehicles are often equipped with one or more cameras, and radars, which can help the driver to keep track of what is happening in the traffic environment around the vehicle.

Jonas_Sjöberg.jpgJonas Sjöberg, Professor of Mechatronics at the Department of Electrical Engineering at Chalmers, who leads the work of developing the self-driving bike, says:

"As a rule, such systems are first launched in premium cars, but after a few years the technology matures and becomes more of standard functions. This is often followed by government requirements for the function to be on board.”
Dummy used for tests
But to require a function, it must be possible to test it. Compared to testing safety features between vehicles, an additional aspect must be considered when unprotected road-users are involved, such as pedestrians and cyclists. It is not acceptable with tests which are potentially dangerous for a test person, and that’s why a robot bike with a dummy will be used in the tests. 

"An automatic system in the vehicle may, for example, need to consider if the cyclist staggers in connection with an overtaking, because the wobbling may increase the risk of an accident. The overtaking then needs to be done with a larger margin. But to test the function, it must be possible to repeat the wobble in the exact same way, time after time,” says Jonas Sjöberg.

A human test cyclist can hardly do this. But a robot bike can be programmed to move identically as many times as you like. Swaying, starting a left turn or driving straight into the roadway - any threatening traffic situation that the vehicle should automatically be able to detect and react to.

"What is available today in the form of test equipment is a bicycle that is pulled on a small sled. This works for simpler tests. But with a robot bike, the manoeuvres could be much more realistic,” says Jonas Sjöberg.

"Generation 2”
There are currently two self-driving bicycles in use within the ongoing research project. According to Jonas Sjöberg, one could say that they belong to "generation 2", even if the development does not follow any strict generational exchanges. It is rather about gradual improvements of the subsystems.

Areas of use
"One of the ultimate goals of the project is that AstaZero will be able to offer a robot bike for those vehicle manufacturers who want to use a programmable bike in test situations,” Jonas Sjöberg says.

But the self-driving bike also has other possible uses, for example actual crash tests, i.e., a vehicle drives on the bike and then you investigate how it went for the test doll that acted as a cyclist.

"It is a type of test that you cannot do with human test cyclists. But, for example, companies such as Autoliv are interested in developing protection for such situations,” Jonas Sjöberg says.

From a sustainability perspective, the research could have a positive impact if a safer traffic environment for cyclists leads to more people daring to cycle in traffic instead of driving, according to Jonas Sjöberg.

Student project
The work with the robot bike has already been going on for a couple of years and a few more years remain before a fully usable prototype is ready. The development is mostly in the form of smaller student projects, where they improve the included subsystems.
robotcykel masterstudenter.jpg
Master stundents working with the robot bike.  Photo: Chalmers

It is mainly master's students from Systems, Control and Mechatronics and engineering students from the Mechatronics program at Lindholmen who participate. Students from Mälardalen University in Västerås are also involved, mainly when it comes to the construction of the electronic.

In addition, a doctoral student is connected to the bicycle project. In his dissertation, Yixiao Wang develops the control algorithm, the mathematical instructions that are responsible for controlling the cycle and regulating speed. This is done based on sensor values that provide information a hundred times per second of the speed, direction, position, and inclination of the two-wheeler. A visiting doctoral student, Guanzheng Wen, from a university in China, is also currently participating in the work.

Vehicle testing
Many of the practical tests take place in Chalmers' large car park on Johanneberg campus, but sometimes there is an excursion to the test track AstaZero, outside Borås, to perform active safety for more realistic vehicle testing.

Whether the trend towards an increase of autonomous vehicles is good or bad for the environment and climate is a more open question.

  • The self-driving bike is driven by an electric motor on the front wheel hub, and it also has a small electric motor on top of the front fork that handles the steering. Several sensors around the bike provide information about speed, incline, GPS data and more. Everything is collected in the central unit, placed on the bar between the saddle and handlebars.
  • On the saddle is a dummy, filled with Styrofoam. Its only function is to be as similar to a cyclist as possible. Without such a resemblance, there is a risk that the safety function in the vehicle does not recognise the object as a bike and then fails to trigger the safety action to avoid an accident. ​
  • The development of the self-driving bicycle takes place in a series of research projects.
  • Participating partners are, in addition to the AstaZero test environment and Mälardalen University, Volvo Cars, Cycleurope and Autoliv and Veoneer.

Written by: Sandra Tavakoli

For more information, contact:
Jonas Sjöberg, Professor of Mechatronics and Head of the Mechatronic research group.​

Page manager Published: Tue 15 Nov 2022.