The two companies have worked closely together, with Pilz taking overall responsibility for system development and providing the expertise behind the safety functionality, industrial design and programming software. DaimlerChrysler developed the image processing algorithms, specified the practical requirements and supported the comprehensive test program.
Pilz and DaimlerChrysler have called the innovation "SafetyEYE" and describe it as a safety-related sensing and control system based on machine vision.
Pilz says the SafetyEYE machine vision system will supersede light curtains and laser area scanners, which it says are inefficient because they only monitor a flat plane. Although mirrors or multiple devices can be used to create faceted protection zones when using light curtains, the protected area is often greater than the hazardous zone - wasting floor space and potentially triggering shut downs earlier than necessary.
Where floor space is very expensive and time is of the essence, Pilz points to the advantages of SafetyEYE machine vision systemas a non-physical safety barrier that can protect a three-dimensional zone closely matching the hazardous zone.
System architecture of Pilz SafetyEYE Machine Vision System:
Each SafetyEYE machine vision system comprises a sensing device with three greyscale cameras and an analysis unit that contains a high-performance computer and a programmable safety and control system. The three-camera sensor unit is mounted above the application. If a breach of the zones is detected, the system responds within 150 milliseconds to signal an alarm, reduce the speed of operation or halt the process, for example.
Zones can be grouped and muting programmed to enable parts to be fed into or out of a process. If the application requirements change, the zones can be quickly and easily reconfigured in software alone – with no hardware changes. Blanking is expected to be added to future versions of the software.
The analysis unit is also able to perform some conventional (non-safety) control functions. In one trial application, a robot placed components into an oven and then into a collection bin. SafetyEYE machine vision system was used to create a safety barrier around the robot and the analysis unit also monitored the amount of product in the bin so that it could be emptied once it was full.
Cost-effective alternative of Pilz SafetyEYE Machine Vision System
Pilz says the total cost of an installed and maintained system can be around 70 per cent lower than a system using light curtains, largely due to faster installation times. The SafetyEYE machine vision system can be installed and commissioned in around two hours, whereas a conventional safety system would take at least a day.
SafetyEYE machine vision system was launched at DaimlerChrysler's Sindelfingen site on 15 November 2006 and went on to cause a great deal of interest at the SPS/IPC/Drives show at Nuremberg two weeks later. The May launch at National Manufacturing Week will be the first time the SafetyEYE machine vision system will be on public view in the Southern Hemisphere. The system already has concept approval from BG and full product approval is due to be in place by April. After that, trial systems will be offered to prospective customers and production systems are expected to be available in September 2007.
The first application for SafetyEYE machine vision system will be on the production line for the new Mercedes-Benz C-Class. Meanwhile, the team developing the SafetyEYE machine vision system is looking ahead to possible future enhancements. One possibility is to distinguish between, say, a human hand and a tool, paving the way for a human operative and a robot to work in parallel on the same assembly.
From safety to security
SafetyEYE machine vision system was developed primarily to protect workers in the vicinity of robots and other machinery operating in automotive plants but the concept is suitable for use in other industries. Apart from protecting people from hazardous objects, the system can also be used to protect objects from people.
Pilz is exploring the use of SafetyEYE machine vision system in museums, art galleries and similar environments where delicate or valuable items need to be clearly visible, yet protected.
The SafetyEYE machine vision system will be previewed for the first time in Australia at National Manufacturing Week in May.