Robotic assembly can be considered a second generation robot task. It is rarely a simple pick and place operation.

Manual assembly requires relatively skillful operatives to employ a combination of hands and eyes to enable the fitting together of a variety of parts to make up an assembly. The operative will also employ judgement in the interpretation of action and reaction to make a satisfactory union of parts. There will be an element of inspection required to ensure that the parts make the correct fit. If it is difficult to assemble the parts, they may have been manufactured out of tolerance. Operatives are also used to assemble parts 'selectively' to accommodate a variation in manufacturing tolerances.

As we know the industrial robot is capable of high repeatability. Even though this will enable accurate alignment, this may not in itself be enough. The importance of 'feel', to assemble 2 closely toleranced parts eg. shaft and bore, should not be underestimated.

The hand tooling, or gripper, in an assembly operation is often critical to it's success. A proven technique to overcome binding during assembly is to build 'compliancy' into the tooling. A compliant gripper will be capable of parallel float relative to the target component, during say insertion of a shaft into a bore.

Force feedback has also been employed to indicate a 'bindup' situation. Whilst this enables the robot to react and retry the operation, this would not be my preferred approach, as it builds additional time into the assembly operation.

A good assembly application will be a combination of good hand tooling design, repeatable manufacturing tolerances and most importantly, product design for ease of assembly with good leads, finishes and a clean environment, to prevent failure and rework.

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