J. D. G. Kooijman

A Bicycle Can Be Self-Stable Without Gyroscopic or Caster Effects

A new bicycle design points to the importance of mass distribution for stability. A riderless bicycle can automatically steer itself so as to recover from falls. The common view is that this self-steering is caused by gyroscopic precession of the front wheel, or by the wheel contact trailing like a caster behind the steer axis. We show that neither effect is necessary for self-stability. Using linearized stability calculations as a guide, we built a bicycle with extra counter-rotating wheels (canceling the wheel spin angular momentum) and with its front-wheel ground-contact forward of the steer axis (making the trailing distance negative). When laterally disturbed from rolling straight, this bicycle automatically recovers to upright travel. Our results show that various design variables, like the front mass location and the steer axis tilt, contribute to stability in complex interacting ways.

Lateral dynamics of a bicycle with a passive rider model: stability and controllability

This paper addresses the influence of a passive rider on the lateral dynamics of a bicycle model and the controllability of the bicycle by steer or upper body sideway lean control. In the uncontrolled model proposed by Whipple in 1899, the rider is assumed to be rigidly connected to the rear frame of the bicycle and there are no hands on the handlebar. Contrarily, in normal bicycling the arms of a rider are connected to the handlebar and both steering and upper body rotations can be used for control. From observations, two distinct rider postures can be identified. In the first posture, the upper body leans forward with the arms stretched to the handlebar and the upper body twists while steering. In the second rider posture, the upper body is upright and stays fixed with respect to the rear frame and the arms, hinged at the shoulders and the elbows, exert the control force on the handlebar. Models can be made where neither posture adds any degrees of freedom to the original bicycle model. For both postures, the open loop, or uncontrolled, dynamics of the bicycle–rider system is investigated and compared with the dynamics of the rigid-rider model by examining the eigenvalues and eigenmotions in the forward speed range 0–10 m/s. The addition of the passive rider can dramatically change the eigenvalues and their structure. The controllability of the bicycles with passive rider models is investigated with either steer torque or upper body lean torque as a control input. Although some forward speeds exist for which the bicycle is uncontrollable, these are either considered stable modes or are at very low speeds. From a practical point of view, the bicycle is fully controllable either by steer torque or by upper body lean, where steer torque control seems much easier than upper body lean.

SOME OBSERVATIONS ON HUMAN CONTROL OF A BICYCLE

The purpose of this study is to identify human control actions in normal bicycling. The task under study is the stabilization of the mostly unstable lateral motion of the bicycle-rider system. This is done by visual observation of the rider and measuring the vehicle motions. The observations show that very little upper-body lean occurs and that stabilization is done by steering control actions only. However, at very low forward speed a second control is introduced to the system: knee movement. Moreover, all control actions are performed at the pedaling frequency, whilst the amplitude of the steering motion increases rapidly with decreasing forward speed.Copyright

A review on bicycle and motorcycle rider control with a perspective on handling qualities

This paper is a review study on handling and control of bicycles and motorcycles, the so-called single-track vehicles. The first part gives a brief overview on the modelling of the dynamics of single-track vehicles and the experimental validation. The second part focusses on a review of modelling and measuring human rider control. The third part deals with the concepts of handling and manoeuvrability and their experimental validation. Parallels are drawn with the literature on aircraft handling and pilot models. The paper concludes with the open ends and promising directions for future work in the field of handling and control of single-track vehicles.

A METHOD FOR ESTIMATING PHYSICAL PROPERTIES OF A COMBINED BICYCLE AND RIDER

A method is presented to estimate and measure the geometry, mass, centers of mass and the moments of inertia of a typical bicycle and rider. The results are presented in a format for ease of use with the benchmark bicycle model [1]. Example numerical data is also presented for a typical male rider and city bicycle.

EXPERIMENTAL VALIDATION OF THE LATERAL DYNAMICS OF A BICYCLE ON A TREADMILL

In this paper, an experimental validation of the lateral dynamics of a bicycle running on a treadmill is presented. From a theoretical point of view, bicycling straight ahead on a treadmill with constant belt velocity should be identical to bicycling on flat level ground with constant forward speed. However, two major differences remain: first, stiffnesses of the contact of the tire with the belt compared to the contact on flat level ground; second, the belt velocity is fixed with respect to the world, irrespective of the change in heading of the bicycle on the treadmill. The admissibility of these two differences is checked by comparing experimental results with numerical simulation results. The numerical simulations are performed on a three-degree-of-freedom benchmarked bicycle model [1]. For the validation we consider the linearized equations of motion for small perturbations of the upright steady forward motion. This model has been validated experimentally in a previous work [2]. The experimental system consists of an instrumented bicycle without a rider on a large treadmill. Sensors are present for measuring the roll rate, yaw rate, steering angle, and rear wheel rotation. Measurements are recorded for the case in which the laterally perturbed bicycle coasts freely on the treadmill. From these measured data, eigenvalues are extracted by means of curve fitting. These eigenvalues are then compared with the results from the linearized equations of motion of the model. As a result, the model appeared to be accurate within the normal bicycling speed range, and in particular the transition from stable to unstable weave motion was very well predicted.Copyright

A REVIEW ON HANDLING ASPECTS IN BICYCLE AND MOTORCYCLE CONTROL

This paper gives an overview on handling aspects in bicycle and motorcycle control, from both theoretical and experimental points of view. Parallels are drawn with the literature on aircraft handling. The paper concludes with the open ends and promising directions for future work in the field of handling and control of single track vehicles.© 2011 ASME

On the Design of a Recumbent Bicycle With a Perspective on Handling Qualities

A novel approach to bicycle design for handling qualities is presented. The design method is introduced through a case study in which a new front-wheel drive recumbent bicycle is developed. Since there exists no proper definition nor assessment for bicycle handling qualities, design process is based on comparing the uncontrolled dynamics of the new concepts to an existing design, known to handle well. A prototype was built and road test were conducted to compare the handling before being taken into production. The new design shows comparable handling.Copyright