Computer-based control systems commercial development

The commercial development of computer-based control systems for tractors and other agricultural implements has provided a platform that enables coded mapped information to be effectively transferred from a desktop computer to the tractor cab. Initially developed in conjunction with GPS field location for yieldmapping applications, this type of system is now being incorporated into tractors and specialised application vehicles (see Figure 4.6). These can be used to give access to the treatment map in the field, and hence control signals for the application system. Data transfer is commonly by smart cards with current systems, but it is likely that future developments will use radio/telephone connections to automate the data transfer process (Miller, 1999). 

Figure 1 shows a computational framework, representing many years of Braun s research and development efforts in pyrolysis technology. Input to the system is a data base including pilot, commercial and literature sources. The data form the basis of a pyrolysis reactor model consistent with both theoretical and practical considerations. Modern computational techniques are used in the identification of model parameters. The model is then incorporated into a computer system capable of handling a wide range of industrial problems. Some of the applications are reactor design, economic and flexibility studies and process optimization and control. 

In mid-1980s, custom-made press monitoring systems were described, ° and the first commercial instrumentation packages became available, including both the systems for product development and press control. The first personal computer-based tablet press monitor was sold in 1987, and the first Microsoft Windows-based press instrumentation package in 1995. 

The growing power of computers and the availability of efficient computation algorithms have led to the development of integrated systems that address the issues discussed above. Several commercial model-based packages exist for process control and online optimization using a variety of methods (STAR, NLC, 2002 RMPC Friedman, 1977). The basic concepts of a typical system are discussed below. 

Nowadays in commercially and govemmentaUy developed military systems digital computer systems are increasingly used for controlling tasks automatically. The software allows replacing decisions based on emotions and doubts by the human operator is often replaced in the control loop by software logic. 

In this paper we present some results from a dynamic study of a commercial nickel-based catalyst using a newly-developed microreactor operating under computer control. The physical size of the reactor was very small and as the flow capacity of the reactor system was high, equilibrium limitations were not significant. The range of operating temperature for which kinetic data were collected was 600-850 C, at pressures from 1.5-10 bar. 

---