Complex safety functions on machinery

Status:

completed 12/2003

Aims:

The principles for integrated safety technology for machinery were drawn up in Research Project 5079  "Integrated safety technology for machinery". The research revealed approaches for improvements in the way machine tools and robots are used, and in the safety offered by such machines. The objective of the project was therefore the drafting of concepts for operating modes necessitating manual intervention whilst the machine is running. These concepts were also used to achieve decisive improvements in the ergonomic arrangements on such machines when interventions are performed by operating personnel.

Activities/Methods:

The concepts drawn up in Project 5079 were extended to the widest possible range of control structures. These included the safe-related single-channel (also wireless) transmission of signals over bus systems, the automatic selection of safe machine functions, and the safe initiation of machine movements without the use of an enabling device. The monitoring measures employed on linear drives were applied to robotics (monitoring of position and speed of the resulting robot movements). The creation of virtual protection zones by means of safe integrated logic was compared to conventional protective devices (such as guards), to establish whether they deliver equivalent safety. All ideas were supported, from initial draft design by analyses, to the final machine by measurements and observations in routine use.

Results:

The combination of drive controls with integrated safety functions, suitable sensors, and safety-related transmission of signals was shown to permit modern operating modes on machines. Human operators need not necessarily be isolated from hazardous movements by guards, but can perform their tasks in direct proximity to hazard points. Potential hazards are detected in good time and movements stopped before injury can occur. Ergonomic requirements for workplaces can be satisfied much better when acknowledgement buttons do not need to be actuated repeatedly, or when manually guided robots assume the task of handling heavy workpieces.

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