Variation analysis toolbox for non-nominal path planning for industrial robots
Abstract
Industrial robots are frequently used in the manufacturing process. One important aspect in the manufacturing process design is to assure that there exists a collision-free assembly path for each part and subassembly including the assembly equipment, e.g. a robot. In order to reduce the need of physical verification the automotive industry uses digital mock-up tools with collision checking for this kind of geometrical assembly analysis. However, in real production, all equipment, parts and subassemblies are affected by geometrical variation, often resulting in conflicts and on-line adjustments of off-line generated assembly paths. This paper presents a variation analysis toolbox for path planning for industrial robots. This toolbox can help to avoid problems with on-line adjustments. The variation analysis includes the variation in joints and actuators in the robot and can also be used by robot manufacturers when designing new robots. A new tool for variation analysis o f a robot path is presented. Also, variation analysis of the product at the assembly line is used to enhance the off-line generated assembly paths. With better knowledge of the variation in the robot and product we can allow the assembly path to reach closer to areas of low variation, while avoiding areas of high variation. The proposed approach is illustrated with test cases.
