Experimental analysis of paddling efficiency of elite and non-elite athletes with instrumented canoe sprint C1

Canoeing is an on-water sport admitted by the International Canoe Federation (ICF) and Canoe Sprint became an Olympic discipline in 1936: its programme includes events over 200 m, 500 m and 1000 m. There are numerous Canoe events in single (C1), double (C2) and four (C4) boats. In this discipline the canoeist is kneeling on one knee, and uses a single-bladed flat paddle. In the same way as kayaking, canoeing is a sport whereby propulsion of the boat is derived mainly from muscle actions of the upper body. Conversely, the kneeling position of the canoeist influences the dynamic behaviour of the hull and the force stroke exerted by the single-bladed paddle results in augmented ‘fluctuation’ of the average speed, in greater roll angle and wider pitch span of the canoe with respect to the kayak boat. Besides, the flat shape of the paddle determines the particular paddling technique. In canoeing high forces must be applied at high stroke rates and athletes are coached both in stroke technique and power or resistance training. Elite athletes stand out for the style and efficiency of the stroke, for power and resistance and for skills in the race strategy. Biomechanical measures of canoeing is an important asset to improve performance. In addition comparing results from test to test enables monitoring of an athlete's yearly, and year-to-year improvement. Finally, the experimental analysis of the main kinematical and dynamical parameters allows to examine the shape of the force curves for stroke error detection purposes and to reduce the ineffective hull movements. In this paper the performance and the paddling technique of two elite and two non-elite canoeists are presented by means of an on-water experimental apparatus. Moreover a comparison between the drive phase of the stroke in kayaking and canoeing is proposed. The goals of this research project were to (1) develop a system for on-the-water measurement of paddling performance in kayaking and canoeing, (2) demonstrate the potential of such a system to quantify efficiency and then (3) compare the main kinematical and dynamical parameters of single K1 and C1 boats and the technique differences in paddling style

Evaluation of Paddling Performances through Force Acquisitions with a Specially Instrumented Kayak Ergometer

This paper presents a prototype machine working as a kayak ergometer, specially designed to closely reproduce the athletic performance during a training K1 indoor session. Drag and inertia actions on paddles are reproduced through a fan connected to the movement of the paddle-bar. The resistance action can be adjusted by regulating the air intake with a shutter, to compensate for size and weight of the paddler. Paddle action, simulated by an instrumented bar with strain gauges at both ends, pulls the rotating fan by means of ropes rolling up on pulleys. Load cells are mounted in correspondence of the bearings of the pulleys, and an encoder is mounted on the fan shaft to measure the rotational speed. This system is particularly suitable to evaluate the paddling performances and to refine the technique of strokes and style

Sensitivity Performance of Input Shapers Applied to Command Profiles as Diagnostic Tool for Flexible Robots

In this paper the motion input pre-shaping method, applied to flexible manipulators for space applications, is analyzed in terms of sensitivity and robustness to parameters uncertainties. The special environment of space operations and the project specifications lead to the design of manipulators with light and flexible structures. In order to highlight the performances of these methods an open loop control technique was implemented. The control technique is verified with both numerical simulations and experiments. This paper presents the results of a series of experimental tests carried out on the Space Robot Simulator assembly, called Test-bed for Microgravity Simulation in Robotic Arm Dynamics (TeMSRAD) (Mimmi et al., 2004), which has been set up at the Dipartimento di Meccanica Strutturale, Università di Pavia. The innovative task of the research was to determine experimentally the sensitivity curve for One- Hump and Two-Hump Extra-Insensitive input shapers, for different vibration limits, by purposely introducing errors in the system model, in order to simulate typical operating conditions

Theoretical and experimental sensitivity analysis of extra insensitive input shapers applied to open loop control of flexible arm

In this paper the motion input pre-shaping, applied to flexible manipulators for space applications, is analyzed in terms of sensitivity and robustness to parameters uncertainties. The special environment of space operations and the project specifications lead to the design of manipulators with light and flexible structures. In order to highlight the performances of these methods an open loop control technique is implemented. The control technique is verified by both numerical simulations and experiments. This paper presents the experimental set-up and the results of a series of experimental tests carried out on the Space Robot Simulator assembly, called Test-bed for Microgravity Simulation in Robotic Arm Dynamics (TeMSRAD). The innovative task of the research is to determine experimentally the sensitivity curve for One-Hump and Two-Hump Extra-Insensitive input shapers, for different vibration limits, by purposely introducin

Apparato sperimentale per indagini diagnostiche su ingranaggi

Il presente lavoro descrive la messa a punto e i primi risultati ottenuti attraverso l’impiego di un apparato sperimentale di prova per studiare problemi di diagnostica relativi ad una coppia di ruote dentate in differenti condizioni di ingranamento. In particolare vengono analizzate posizioni degli assi diverse per distanza. Inoltre viene confrontato il segnale prodotto da un ingranaggio danneggiato con quello prodotto da un ingranaggio integro. I segnali indicatori del malfunzionamento sono ottenuti attraverso trasduttori quali: encoder, resolver, accelerometri e sensore a raggio laser. I dati sono acquisiti in maniera digitale ed elaborati per l’indagine diagnostica

A Low-Cost Implementation of an Eye Tracking System for Driver’s Gaze Analysis

We present an eye tracking system developed to study the driver’s gaze behavior while driving a car. Two main challenges distinguish this project from similar works with analogous purposes: (1) the use of a cheap portable remote eye tracker, normally employed for indoor applications in controlled light conditions; and (2) the use of an ordinary webcam to shoot the road in front of the car. The purpose is to generate a video where the driver’s fixations are graphically and dynamically superimposed on the road shot by webcam (taking into account the different viewpoints of driver and camera). The carried-out experiments confirmed that the implemented system, while perfectible, fulfills the requirements initially set

An Experimental Test-Bed for Microgravity Simulation in Robotic Arm Dynamics

This paper describes an experimental testing apparatus set up by the authors in order to validate the effectiveness of the motion input pre-shaping technique for the open-loop control in microgravity environment. The system consists of a two flexible links planar manipulator suspended on special air-pads floating on a planar friction-free glass surface. Since the friction between the two pads mounted on the manipulator and the platform is reduced to almost zero, the planar dynamics of the system very closely approximates the dynamics in a microgravity environment. In order to focus on the motion inputs, the brushless motors are controlled in speed mode

Multivariable predictive control for vibrating structures: An application

This paper proposes the use of Model Predictive Control (MPC) to control a fast mechanical system. In particular an MPC strategy is applied to a laboratory flexible arm to perform a fast positioning of the end-effector with limited oscillations during the maneuver. The on-line implementation of a fast MPC is obtained with an ad hoc platform based on Cþþ and MATLAB while the MPC tuning is based on a nonlinear model identified and validated with experimental data. The effectiveness of the proposed method is highlighted with some suitable experiments performed on the plant. In particular the comparison with a Linear Quadratic Regulator stresses the advantage of the MPC capability to explicitly handle input and state constraints.This feature guarantees smaller displacements that imply a structure stress reduction

An original 3-D cycle ergometer (3-DCE) for three-axial force measurements

In this paper is presented an original prototype of cycle ergometer suitable for measuring the three components of the force exerted by the two feet on the two pedals. The prototype is a cycle ergometer suitably instrumented to collect quantitative data that allow the kinematics and dynamics of the bicycle-rider model to be solved. A tri-axial load cell, which measures the pedalling force in three orthogonal directions, and two encoders, that measure the angles between the feet and the central movement, are mounted on each pedal. These angles are measured through encoders as well as the crank rotation of the central movement

Open-Loop Control of a Flecible Manipulator with Two Links: Experimental Results

This paper describes the experimental results of an open loop control technique applied to a flexible manipulator, specially designed for space duties, in order to reduce the residual vibrations at the end of the positioning. The experimental set up is a system with two flexible links with rectangular section connected by rotational joints. First, the experimental identification of the system parameters has been carried out. Then, four different motion inputs have been implemented. The performances of these motion inputs are compared in terms of residual vibration at the end of the positioning. The experimental results confirm the effectiveness of the motion input pre shaping technique in the reduction of the residual vibrations