Bicycle Rider Control: Observations, Modeling & Experiments

Bicycle designers traditionally develop bicycles based on experience and trial and error. Adopting modern engineering tools to model bicycle and rider dynamics and control is another method for developing bicycles. This method has the potential to evaluate the complete design space, and thereby develop well handling bicycles for specific user groups in a much shorter time span. The recent benchmarking of the Whipple bicycle model for the balance and steer of a bicycle is an opening enabling the accurate modeling of a bicycle and making this engineering route very viable. However the route also requires a rider model in order to be successful, but at present, very little is known about the bicycle rider. The aim of this work is to get a step closer to being able to determine a-priori the handling qualities of bicycles and thereby enable the development of better, safer and out of the ordinary bicycles. To this end observation experiments have been performed to discover what control actions a rider performs on a bicycle and observed rider motions have then been implemented in a passive rider model. Furthermore the almost universally accepted requirements for bicycle self stability of spin angular momentum (gyroscopic effect) and trail have been shown experimentally to not be necessary.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin

Balance and control of a rear-wheel steered speed-record recumbent bicycle

The goal of the Human Power Team from the TU Delft and the Free University of Amsterdam is to break the world speed record in unpaced cycling (Sam Whittingham, 133.28 km/h). The design of such a faired recumbent bicycle is a challenge. The Delft design, called VeloX (Human Power Team (2013)), is a fully-faired monocoque front-driven recumbent bicycle, with minimized air drag and maximized space for a big and strong athlete. However, front driven bicycles have the disadvantage that the front driving induces unwanted steering and that the frontal area of the bicycle cannot be reduced any further. A solution would be rear-wheel steering. A common thought is that a rear-wheel steered bicycle cannot be laterally self-stable, and therefore hard to control. However, recent research (Knoll et al. (2012)) has shown that one can design a rear-wheel steered bicycle which shows a stable forward speed range. Based on these results a rear-wheel steered recumbent bicycle has been designed, within the existing design constraints. Although not self-stable, this design shows a mildly lateral unstable behavior in the desired forward speed range of 0 to 40 m/s (0 to 144 km/h). Computer simulations demonstrate that the bicycle can be stabilized by adding a human controller model (Schwab et al. (2013)) to the bicycle model. For a set of expected lateral perturbations (side wind perturbations) it is shown that rider steer torque stays within human bounds, both in magnitude and in frequency. Future work is dedicated to building and testing a prototype of the design.Biomechanical EngineeringMechanical, Maritime and Materials Engineerin

Rider motion identification during normal bicycling by means of principal component analysis

Recent observations of a bicyclist riding through town and on a treadmill show that the rider uses the upper body very little when performing normal maneuvers and that the bicyclist may, in fact, primarily use steering input for control. The observations also revealed that other motions such as lateral movement of the knees were used in low speed stabilization. In order to validate the hypothesis that there is little upper body motion during casual cycling, an in-depth motion capture analysis was performed on the bicycle and rider system. We used motion capture technology to record the motion of three similar young adult male riders riding two different city bicycles on a treadmill. Each rider rode each bicycle while performing stability trials at speeds ranging from 2 km/h to 30 km/h: stabilizing while pedaling normally, stabilizing without pedaling, line tracking while pedaling, and stabilizing with no-hands. These tasks were chosen with the intent of examining differences in the kinematics at various speeds, the effects of pedaling on the system, upper body control motions and the differences in tracking and stabilization. Principal component analysis was used to transform the data into a manageable set organized by the variance associated with the principal components. In this paper, these principal components were used to characterize various distinct kinematic motions that occur during stabilization with and without pedaling. These motions were grouped on the basis of correlation and conclusions were drawn about which motions are candidates for stabilization-related control actions.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin

Statistics of bicycle rider motion

An overview of bicycle and rider kinematic motions from a series of experimental treadmill tests is presented. The full kinematics of bicycles and riders were measured with an active motion capture system. Motion across speeds are compared graphically with box and whiskers plots. Trends and ranges in amplitude are shown to characterize the system motion. This data will be used to develop a realistic biomechanical model and control model for the rider and for future experimental design.Precision and Microsystems EngineeringMechanical, Maritime and Materials Engineerin

Bicycle Design: A different approach to improving on the world human powered speed records

The current International Human Powered Vehicle Association world records for faired bicycles stand at 133.284km/h for the 200m flying start speed record and 91.562 km for the hour record. Traditionally the recumbent bicycles that have been developed for breaking one of either of these records have been optimized around a specific, relatively small rider, enabling the overall size to be kept small. Creating the smallest frontal area possible and optimal aerodynamic shape were then the design goals. This paper discusses the development of the Velox recumbent bicycle, which has been designed using another approach. The power required to break either of the records depends mostly on air resistance. Therefore small riders have the advantage of allowing for smaller frontal areas, whilst larger riders are able to provide more power. Performance optimization, lead to a design based around an average 1.95m tall male rider for Velox. The aerodynamic shape of Velox was then developed around the above criterion and designed with CFD and validated with wind tunnel and road tests. Essential for the rider’s performance is that the rider feels comfortable whilst riding the bicycle. Therefore the uncontrolled lateral dynamics and the required rider steer control input were investigated. The bicycle’s geometry was optimized for low speed stability and the required control input.Mechanical, Maritime and Materials Engineerin