· Title: Study of sensory perception in the hands of cyclists in connection with the dynamic comfort of road bicycles

 

· Status: Ongoing project

 

· Background: The VÉLUS Laboratory seeks to understand the vibration behaviour of road bikes by combining experimental and numerical modelling approaches. Several new sensors, measurement techniques and protocols, experimental test benches, and numerical models have been developed. The sensors developed by VÉLUS were the subject of several scientific articles and come in the form of instrumented bicycle components (e.g. instrumented brake hoods, instrumented seat post, instrumented pedals). They play a key role because they allow to quantify with precision the amount of vibration transmitted to the cyclist at its contact points with the bicycle (i.e. hands, buttocks, feet) in terms of force and acceleration.

 

Most of VÉLUS' activities has so far focused on the mechanical aspects of bicycle dynamic comfort. As comfort is fundamentally linked to the sensory perceptions of the cyclist, the next logical step for VÉLUS is to investigate these perceptive aspects including the relationship between cyclist’s perception and vibration levels (in terms, for example, of acceleration, force and power) transmitted to his points of contact with the bicycle.

 

· Main objective / Description: This project aims to increase knowledge about sensory perception in the hands of cyclists in connection with the dynamic comfort of road bicycles. It will include identifying the methodological and experimental features of perceptual tests carried out on a road bicycle. Ultimately, this will set the test protocol that will be used for future perception studies carried out by VÉLUS. The elements to be covered to achieve this include:

 

    - Psychometric curves;

    - Perceptual thresholds and the "Just noticeable difference in level" (JNDL);

    - The merits of mechanical quantities (e.g. force, acceleration, power) as comfort metrics;

    - The variability of the measurement of these mechanical quantities directly attributable to the cyclist;

    - The effect cyclist expertise on his perception test performance.

 

· Partner: McGill University (Prof. Catherine Guastavino and Prof. Ilja Frissen)

· Title: Physical characterization and perception of vibration transmission of road bike components

 

· Status: Completed

 

· Summary: Dedicated cyclists spend hundreds of hours each year on their bikes. The need for lightweight and high-performance bikes is justified, as is the desire for comfort. Vibrations generated by defects in the road surface are a significant source of discomfort, fatigue and disincentive to ride, therefore the capability to filter these vibrations is paramount. Our research objective is to improve dynamic comfort, which we define as reducing the level of vibratory discomfort. Designing a road bike with comfort in mind is a major challenge, because contrary to other types of bicycles (i.e. mountain bikes), road bikes have no suspension system: isolation from vibrations therefore depends mainly on the dynamic behaviour of bike components. Stakeholders in the cycling industry have shown their interest in features that enhance comfort. Second to being lightweight, the capacity to filter vibrations is one of the most oft-mentioned desirable characteristics in a bike.

 

The principal focus of this research project is to study and understand vibration behaviour in bikes, and develop design tools that will enable engineers to produce more comfortable bikes. The project will combine experimental approaches with numerical modeling techniques. Several new transducers, measurement techniques, experimental test benches and numerical models will be developed. We will also study the significant influence of the cyclist on the dynamic response of the bike. Comfort is fundamentally related to the cyclist's perceptions. Our project will thus examine the cognitive dimensions of the rider's own assessments of "dynamic comfort", which will involve quantification of thresholds and parameters that can influence the cyclist's ability to perceive and differentiate variations in vibration levels. Through the development of new knowledge, designs and numerical models, our industrial partnership with Vroomen-White Design will introduce innovative and comfortable bikes to a very competitive international market.

 

· Partners: VWD-Cervélo, McGill University

· Title: Study of the dynamic behaviour of bicycle frames for the development of a metric related to comfort

 

· Status: Completed

 

· Background: In the world of cycling, and in particular for long-distance riders, comfort is a first-order concern. Manufacturers of bicycle frames and components emphasize the comfort features of their product. However, no scientific tool is available to adequately (i.e. scientifically) measure the level of comfort of a bicycle.

 

· Main Objective: To understand the dynamic behaviour of a road bicycle in relation to the quantification and comfort perception felt at the hands of the cyclist.

 

· Description: Due to its multidisciplinary nature, this project was divided into three parts: 1) analysis of the dynamic behaviour of a road bike; 2) determination of a comfort-related metric and 3) perception of comfort while on the bike. In the first part we investigated the dynamic characteristics of the structure by testing under various conditions. The modal analysis and the vibration test were used to determine the dynamic behaviour of the bike with and without components, but also with and without a cyclist. In part two, the determination of a metric related to comfort yielded a procedure to determine the energy content of the force transmitted to the hands of the cyclist. This metric constitutes an interesting and measurable physical parameter to quantify the perception of comfort associated with the front part of the road bike. Finally, comfort perception makes it possible to propose an answer to the average sensory resolution of a cyclist using the JNDL technique (Just Noticeable Difference in Level). This sensory resolution makes it possible to interpret the perception (or non-perception) of differences between two bicycles or two components.

 

· Partners: Argon 18 inc., Centre Québécois de recherche et développement sur l'aluminium (CQRDA), Cycles Devinci inc., Procycle Group inc.

· Title: Measurement of dynamic forces applied to a road bicycle in real conditions of use

 

· Status: Completed

 

· Background: To predict the fatigue life of a road bicycle requires experimental testing. The mechanical loads of a bicycle frame depend on several factors, such as the size of the frame, the cyclist’s weight and position, road imperfections, etc. For the optimal design of a bicycle frame, it is essential to know the forces in real conditions of use at the various load entry points on a frame.

 

· Main Objective: The objective of this R&D project was to develop the technology and measurement systems to enable Cycles Devinci to measure the amplitude of the dynamic stresses of a road bicycle in real conditions of use. The strain at several critical locations on the frame also had to be measured. This information was used to establish a loading pattern for fatigue life prediction. With the data and the use of FEM, it was possible to optimize product design.

 

· Description: In collaboration with Cycles Devinci engineers, several dedicated sensors were designed, manufactured, calibrated and used on a road bicycle. The following sensors were developed:

 

    · Front hub: 2 degrees of freedom (dof) on both drop-outs

    · Rear hub: 2 dof on both drop-outs

    · Clipless pedal: 2 dof on both pedals

    · Stem: 3 dof

 

· Partners: Centre québécois de recherche et développement sur l'aluminium (CQRDA), Cycles Devinci inc.

· Title: Measurement of bike frame stress and dynamic forces applied to a double suspension bicycle in real conditions of use

 

· Status: Completed

 

· Background: Mountain bike manufacturers face a difficult challenge: the bicycles they design must be simultaneously efficient, easy to drive, durable and as lightweight as possible. Mountain bikes undergo significant shocks on rough terrain, but weight reduction is also a top priority design criteria for manufacturers. Knowing that a bicycle is already a light structure, it becomes a real challenge to reduce its mass while ensuring adequate resistance. To optimize the frame design, manufacturers frequently use the finite elements method (FEM). This technique enables them to calculate the constraints at any point on the structure. However, to be able to predict realistic stress levels, it is essential to know the mechanical loads (forces and couples) that are being applied to the frames in real conditions of use. Cycles Devinci took up this challenge by collaborating with the researchers at VélUS to develop an instrumented mountain bike.

 

· Main Objective: To develop sensors and technologies to measure mechanical loads on a mountain bike in real conditions of use.

 

· Description: In collaboration with the engineers of Cycles Devinci, a series of specific sensors were designed, manufactured, calibrated and installed on a mountain bike. The sensors made it possible to simultaneously measure the following loads and the kinematics parameters (36 signals were recorded) (H = horizontal and V = vertical):

 

    · Force on the front and rear wheel axles (H & V);

    · Left and right handlebar force (H & V);

    · Saddle force (H & V);

    · Front and rear wheel disc brake force;

    · Force delivered by the rear spring suspension;

    · Force at both clipless pedals (H & V);

    · Crank position;

    · Relative angular position of the pedals to the crank;

    · Instantaneous speed of the front and rear wheels;

    · Front and rear suspension displacement;

    · 3D absolute acceleration of the bike frame.

 

· Partners: Centre québécois de recherche et développement sur l'aluminium (CQRDA), Cycles Devinci inc.

· Title: Use of dynamometric pedals in designing a tool to assist cyclist training

 

· Status: In progress

 

· Background: In elite cycling, the efficiency of the pedaling technique is closely related to the application of an appropriate force pattern to the pedals. The measurement in real time of the pedaling forces should provide valuable insight to trainers in diagnosing and improving athletes’ performance.

 

· Main Objective: Using dynamometric pedals developed by the VélUS team, the objective of this project is to identify for track cyclist population (Elite level), key parameters linked to the pedaling pattern that affect performance and to develop a tool to assist trainers.

 

· Description: The dynamometric pedals developed by the team have a double platform and can be equipped with the LOOK clipless pedal or the Shimano 600 track pedal. Each instrumented pedal makes it possible to measure the forces in the pedaling plane. An encoder set on the pedal allows us to measure the angular position of the pedal relative to the crank position. An encoder is also installed on the bike frame to measure the angular position of the crank relative to the frame. The data from the pedals and from the encoders are stored using a data acquisition system carried in the cyclist’s backpack. Special software to post-process the data and show the results is currently being developed with the goal of calculating the effective component of the total force and several other parameters such as the effective power and the asymmetry index. New parameters that would guide the trainers are being developed and tested.

 

· Partners: Fondation d'Entreprise de la Française des Jeux (France), INSEP (France).

· Title: Development of a calibration system for bicycle ergometers, Home Trainers and bicycle power monitoring devices

 

· Status: Completed

 

· Background: The power developed by an elite level cyclist is a fundamental parameter both for evaluation and training. Measurement of this power is made possible by the use of various specially designed devices and set-ups, such as HomeTrainers, Ergometers, and bicyle power monitoring devices (SRM crank, PowerTap hub or Ergomo bottom bracket for example). Accuracy in measurement is essential for optimizing athlete training. It is surprising to observe that the readings of pedaling power provided by some of these devices can sometimes be out of scale by more than 100 watts.

 

· Main Objective: To develop a calibration system for bicycle power measurement systems.

 

· Description: As for any measuring apparatus, regular calibration is required. Calibration must take into account all the factors that may affect the measurement of the power delivered by the athlete. The calibration rig developed by VélUS is essentially a torque reaction measuring device. The calibration principle consists of applying a known workload to the crank axle and comparing this workload with the one displayed by the equipment being calibrated. Since the power is applied directly to the left hand side of the crank axle, it is possible to calibrate most of the power measurement systems. The calibration system is easy to use by non-expert personnel and this is done, in part, by providing specialized software to guide and to assist the user during the calibration procedure.

 

· Partners: Centre national multisport-Montréal, Centre national de cyclisme de Bromont.

 

Best Paper Award

 

THE ENGINEERING OF

SPORT 11

2016 ISEA CONFERENCE

July 11-14, 2016

Delft, The Netherlands

VÉLUS Laboratory

Dept. of Mechanical Engineering

Université de Sherbrooke

2500 boulevard de l'Université

Sherbrooke (QC) J1K 2R1

Canada

Map