In recent years, researchers from both academia and industry have made great strides in bringing automated vehicles within reach of consumers. Although automated cars have been a primary focus, automated bicycles present an attractive set of advantages: they are more affordable, environmentally friendlier, more maneuverable, and safer due to their weights and speeds. In addition to their commercial potential, bicycles are well suited for research into rehabilitation and human-robot interactions, offering many contact points (e.g., pedals, seat, handlebars) with which sensors can be integrated. However, bicycle automation is confronted by the challenge of balance maintenance. Current balancing methods can be classified into four groups: (1) control moment gyroscope (CMG), (2) mass balancing, (3) reaction wheel, and (4) steering control. Steering control methods feature real-time responsiveness and significantly lower energy consumption but underperform at low forward speeds. Therefore, a steering control design that operates effectively over a wide range of speeds can prove to be a crucial factor in the adoption of automated bicycles.
Researchers at Arizona State University have developed a modified electric bicycle with motor-assisted steering and real-time monitoring of roll angles. Stable, robust steering controllers achieved self-balance at forward speeds ranging from 2 m/s (4.4 mph) to 5 m/s (11.2 mph). With the steering motor mounted parallel and beneath the steering column, manual operation by the rider is still possible without hindrance. More conventional designs replace the handlebars with the motor mounted concentrically over the steering shaft, thus preventing any manual steering. In addition, the electronic control box mounted in the center triangle of the bicycle frame is designed to accommodate supplementary CMG steering components for future hybrid embodiments.
A video showing balance testing is available here.
• Autonomous bicycles
• Human-robot interaction
Benefits and Advantages
• Innovative – Invention represents the first compact motorized steering mechanism for bicycles
• Unobtrusive – Control box and steering mechanism do not interfere with normal bicycle usage
• Reliable – Self-balancing performance verified over a range of speeds
• Power-saving – Steering control method emphasizes energy efficiency