Open, Modular Architecture Controls at GM Powertrain — GMPTG PC-Based Control System Implementations

By C. Michael Taylor, et al. January 28, 1998
Spectrum of Control Applications at GMPTG
Current Implementation of PC-Based Control Systems
In order to execute the control strategies, GMPTG started to implement PC-based control systems on its factory floor. It needs to be clarified that a PC-based control system is only the first step toward the realization of the OMAC concept. The initial implementation of PC-based control systems enables an ‘open’ hardware platform to be used on the factory floor, even though there are still proprietary elements in the software environment. GMPTG is working to gradually replace the proprietary elements in the PC-based control systems, and eventually will reach the desired level of openness, with the most appropriate technologies at an acceptable cost.

Spectrum of Control Applications at GMPTG

Many people are concerned that PC-based control systems do not have the capability to handle complicated manufacturing operations in automotive plants. However, if one surveys the manufacturing applications in GMPTG today, approximately 95% of the applications are fairly straightforward with simple control requirements. Engineers have the tendency to solve the most complicated problems first with advanced technologies. However, the OMAC initiatives are designed to conquer difficulties associated with the 95% lower end manufacturing applications. Figure 6 gives a pictorial view of the spectrum of GMPTG control applications. The various control architectures indicate added functions and capability of a controller when applications become more and more complicated. The control architecture can be as simple as a low end PC running a single task to one that may require multiple operating systems and special purpose sub-systems. Traditional wisdom says that the basic PC architecture does not have the capability to handle the most complicated applications, and VMEbus based controllers are required. With the advent of PCI bus technology, GMPTG personnel believe that the basic PC platform can be used to cover the full spectrum of applications, with co-processor cards integrated in the systems when appropriate.

Figure 6. The spectrum of GMPTG Control Applications

Current Implementation of PC-Based Control Systems

GMPTG implemented the first PC-based control system on a dial index machine in its Warren Transmission plant in 1986 using a software package called FloPror. FloPror is a flowchart programming package that runs on a standard personal computer and performs discrete logic control functions. It started as a test project to validate the technology and resulted in approximately twenty machines being retrofitted with FloPror systems over the years. The types of machines being controlled by the FloPror is a flowchart programming package that runs on a standard personal computer and performs discrete logic control functions. It started as a test project to validate the technology and resulted in approximately twenty machines being retrofitted with FloPror systems over the years. The types of machines being controlled by the FloPror systems include press machines, conveyor systems, dial machining systems, transfer machines, part blasters, laser stations, and assembly machines. Even though one can argue that the FloPror system is really a proprietary control system because of the closed software architecture, the successful implementation of FloPror systems demonstrates that the personal computer architecture, is capable of handling plant floor control tasks. The experience also introduced the paradigm of using flow chart programming for control applications. Building on the success at the Warren Transmission plant, GMPTG implemented PC-based control systems in the GMPTG Windsor Transmission Plant for the 4T40E program in 1991. This 600 million dollar program utilizes more than 300 industrialized personal computers and FloPror software to perform PLC applications. The start-up of the program was successful without major difficulties. Since then, many enhancements, such as advanced diagnostics capability, on-demand production status reports, video capability, and motion control are being incorporated in the control systems because of the flexibility and openness of the personal computer architecture.Following the Windsor program, GMPTG continued the PC-based control revolution by committing to PC-based control for the 1.0 billion dollar GENIII V-8 engine program. More than 350 PC-based control systems are in the process of being implemented at the GMPTG Romulus facility. Other smaller scale PC-based control applications have also been implemented in GMPTG Flint, Toledo, Saginaw, and St. Catharines facilities. Furthermore, PC-based control systems are currently being designed and integrated for two new engine programs that will be implemented in up to six plants around the world. systems include press machines, conveyor systems, dial machining systems, transfer machines, part blasters, laser stations, and assembly machines. Even though one can argue that the FloPror system is really a proprietary control system because of the closed software architecture, the successful implementation of FloPror systems demonstrates that the personal computer architecture, is capable of handling plant floor control tasks. The experience also introduced the paradigm of using flow chart programming for control applications.

Building on the success at the Warren Transmission plant, GMPTG implemented PC-based control systems in the GMPTG Windsor Transmission Plant for the 4T40E program in 1991. This 600 million dollar program utilizes more than 300 industrialized personal computers and FloPror software to perform PLC applications. The start-up of the program was successful without major difficulties. Since then, many enhancements, such as advanced diagnostics capability, on-demand production status reports, video capability, and motion control are being incorporated in the control systems because of the flexibility and openness of the personal computer architecture.

Following the Windsor program, GMPTG continued the PC-based control revolution by committing to PC-based control for the 1.0 billion dollar GENIII V-8 engine program. More than 350 PC-based control systems are in the process of being implemented at the GMPTG Romulus facility.

Other smaller scale PC-based control applications have also been implemented in GMPTG Flint, Toledo, Saginaw, and St. Catharines facilities. Furthermore, PC-based control systems are currently being designed and integrated for two new engine programs that will be implemented in up to six plants around the world.