Marcin Suszyński

Optical scanner assisted robotic assembly

Purpose This paper aims to propose the method of automatic robotic assembly of two or more parts placed without fixing instrumentation and positioning on the pallet. Design/methodology/approach Assembly tasks performed by industrial robots are usually based on a constant program, extensive tooling, fixing objects in a given place and a relatively limited sensory system. In this study, a different approach is presented. The industrial robot program is adjusted to the location of parts for assembly in the work space. This leads to a transition from a clearly defined assembly sequence realized by the industrial robot to the one in which the order of execution of the assembly operations can be determined by the mutual position of parts to be assembled. Findings The method presented in this study combines many already known algorithms. The contribution of the authors is to test and select the appropriate combination of methods capable of supporting robotic assembly process based on data from optical 3D scanners. The sequence of operations from scanning to place the parts in the installation position by an industrial robot is developed. A set of parameters for selected methods is presented. The result is a universal procedure that determines the position of the preset models in partial measurements performed at a fixed relative position of the sensor, the measurement object. Originality/value The developed procedure for determining the position of the parts is essential to develop a flexible robotic assembly system. It will be able to perform the task of assembly on the basis of appropriate search algorithms taking into account the selected and implemented sequence of assembly position and orientation of parts, particularly the base unit freely placed on an assembly pallete. It is also the basis of a system for testing different algorithms to optimize the flexible robotic assembly.

No Clamp Robotic Assembly with Use of Point Cloud Data from Low-Cost Triangulation Scanner

The paper shows the clamp-less assembly idea as a very important one in the modern assembly. Assembly equipment such as clamps represent a significant group of industrial equipment in manufacturing plants whose number can be effectively reduced. The article presents the concept of using industrial robot equipped with a triangulation scanner in the assembly process in order to minimize the number of clamps that hold the units in a particular position in space. It also shows how the system searches for objects in the point cloud based on multi-step processing algorithm proposed in this work, then picks them up, transports and positions them in the right assembly locations with the use of industrial robot manipulator. The accuracy of the positioning of parts was also examined as well as the impact of the number of iterations of the algorithm searching the models in the point cloud on the accuracy of determining the position of the objects. The tests show that presented system is suitable for assembly of various items as plastic packaging and palletizing of products. Such kind of system is the basis for modern, fully flexible assembly systems.

Modelling of a contact pressure distribution caused by assembly errors in a spur gear transmission

Following paper presents development and results of finite element structural simulations prepared in order to estimate contact pressure distribution on teeth flanks of gear transmission caused by assembly errors. In first paragraphs, importance of alignment precision of gear transmission components is described. As well, influence of machining and assembly errors on spur gear transmission was introduced. In last part of introduction, innovations in spur gear transmissions assembly processes were described. Process of finite element analysis preparation was presented. Preparation of FEA included development of geometrical model, boundary conditions, discretization of model and definition of external loads. Results of conducted simulations was presented. Especially, contact pressure distribution irregularities caused by misalignment of shafts were examined Obtained data covered correlations between both direction and magnitude of assembly errors with contact stress distribution along tooth length. Conducted tests proved that in case of great-module geared transmission, shaft misalignments in plane which includes gears axes has far lesser influence on contact stress distribution than misalignments in perpendicular direction.