Quasi-static path optimization for industrial robots with dress packs
Journal article, 2021

Problems with robot dress packs are a major reason for on-line adjustments of robot programs and down-time in robot stations. It is therefore of high value if the physical behaviour of the dress packs can be considered with simulation methods already during the off-line programming process for a robot station. This paper presents a method for quasi-static path optimization for an industrial robot with respect to its deformable dress pack. Given an initial collision-free path generated by an automatic path planner, the via point configurations of the path are optimized with respect to the performance aspects of the dress pack. The method is derived from a general framework for parameter optimization of a mechanical system subject to quasi-static motions and deformations. The optimal parameter values are obtained from numerical solutions to a non-linear programming problem in which the static equilibrium equations of the system hold at discrete times. Due to the large-scale nature of this problem, a dress pack is modelled as a discrete Cosserat rod, which is the preferred choice for modeling large spatial deformations of a slender flexible structure with coarse discretization. The method is applied to an industrial robot moving in-between stud welding operations in a stud welding station. The optimized path reduces the stress in the dress pack and keeps the dressed robot from the surrounding geometry with a prescribed safety clearance during the entire robot motion.

Robot path optimization

Robot dress packs

Quasi-static simulation

Non-linear programming

Parameter optimization

Cosserat rods


Tomas Hermansson

Chalmers, Industrial and Materials Science

Fraunhofer-Chalmers Centre

Johan Carlson

Fraunhofer-Chalmers Centre

Joachim Linn

Fraunhofer Institute for Industrial Mathematics

Jonas Kressin

Fraunhofer-Chalmers Centre

Robotics and Computer-Integrated Manufacturing

0736-5845 (ISSN)

Vol. 68 102055

Smart Assembly 4.0

Swedish Foundation for Strategic Research (SSF) (RIT15-0025), 2016-05-01 -- 2021-06-30.

Subject Categories

Materials Engineering


Control Engineering

Computer Science

Areas of Advance




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