TESTING SPORTS SHOES USING AN INDUSTRIAL ROBOT

Abstract

INTRODUCTION: Sports shoes are a very important type of sports equipment and are subject of constant development and improvement, especially for winter sports like skiing, cross country skiing, skating, etc. Basically, the design of ski boots is based on trial and error methods, where each prototype is tested on the outdoor terrain. This development approach is very time-consuming and costly. Besides, it is affected by the personal judgement of the subject. The main goal of this project was to develop methods and equipment for reliable sports shoes testing. METHODS: In the paper we propose new approach to sports equipment testing. It consists of two major phases: measurement phase and simulation phase. In the measurement phase we capture the forces and trajectories that occur during the sports activity. Along with the trajectory, video images of the sports activity are recorded, which enables the identification of the sports activity during the simulation phase. In the simulation phase, we use an industrial robot that exactly repeats the captured motions. Using additional measurement equipment, various forces, vibrations, etc. can be measured on any part of the sport shoe. The main benefit of this approach is that many sports shoes can be measured and compared under exactly the same conditions. Additionaly, laboratory environment makes possible measurements that are very difficult or impossible to perform on the terrain.The proposed approach was already used for testing alpine ski boots and cross country ski boots. The alpine ski boots testing is less complex than the cross country ski boots testing, Due to the rigidity of the alpine ski boot only the motion and forces in sagital plane have to be measured, which was accomplished using mechanical measurement device. On the other hand, complex motion caused by cross country skiing had to be determined using an ELITE 3D optical measurement system. RESULTS: Using this methodology and developed equipment we formed a database of motion and force test trajectories belonging to various types of sports activities, such as race skier's giant slalom turn, advanced skier's ski turn, beginner's ski turn, cross-country skier's sliding and skating cycles etc. These trajectories were classified for competitors and recreatives according to snow conditions and ski slope angle. Simulation of the motion trajectories on different models of sports shoes by the use of a robot and simultaneous measurement of reactive forces helped to identify which part of the sports shoes had to be redesigned regarding specific demands of the user. CONCLUSIONS: The proposed approach was used for testing alpine ski boots and cross country ski boots. The measurement results allow a comparison among different types of ski boots. Our system for alpine ski boots testing has been used for ski boot design by one of the world's leading ski equipment manufacturers.