Department for Automation, Biocybernetics and Robotics

Integration of CAD systems in production processes in shoe assembly

Project duration: 2004 - 2006
Project area: Automation and Intelligent Control of Robots
Project type: Applied research
Project funding: Research Agency
Project leader: Leon Žlajpah

Alpina d.d. Žiri


The aim of the proposed project is the automation of shoe assembly. A special attention will be given to two items: to the connection between the CAD system for designing the shoe and the automated cells in the production of the shoe, and the implementation of advanced sensory system in the automation of the shoe assembly process. The main issue is how to link the shoe design process with the production of the shoe.

Project description

The main contribution of the R&D project is the integration of the design CAD phase with the production.  This approach was implemented in the shoe manufacturing industry, but can be applied also in other similar industries.  Our approach differs from the already existing approach using postprocessors for NC code generation from CAD design. Namely, in automatic code generation for industrial robots it is extremely difficult to achieve 'safe' trajectories.  Safe trajectories are trajectories which assure that the robot will not collide with the environment, will avoid the singular configuration and will not violate joint limits, velocities sand accelerations. Our approach of automatic generation of safe trajectories relies on control theory of kinematically redundant robots. We developed also a new very efficient approach, where we describe task redundancy due to the circular shape of the work tool as a virtual mechanism.

We have developed, designed and build two work cells, one for the automation of the gluing of the shoe sole and the other for the shoe bottom roughing and pre-roughing.

In the developed work cells we have completely eliminated the need for manual teaching. All trajectories are generated automatically from the reference CAD model of the shoe and downloaded to the cell controller. For the generation of the ‘safe’ trajectories we have developed also an expert system.

The shoe production industry was an important industry branch in Slovenia in past.  Recently, due to the higher labor cost, most of Slovenian footwear industry closed the business or moved the production to far-east countries. Alpina is the only footwear producer that resists the aggressive competition due to the market globalization, mostly due to the higher automation and good program, oriented in sports and trekking shoes. New business opportunity is offered with the custom made shoes, where it is expected that low-cost footwear producers will not be able to offer. However, the production of custom made shoes has to be highly automated in order to diminish the effect of higher labor cost on one hand and increase the product quality and reliability on the other hand. Therefore we can claim that this project directly affects the competitive position of the Slovenian footwear industry. It will directly and indirectly increase also the education level in footwear industry.


Founding: ARRS - Slovenian Research Agency (L2-6629)

Co-financed by Alpina d.d. Žiri