Digital guidance of an unmanned battery electric vehicle

Abstract

Automation in industry provides both cost and management benefits. Within the materials handling field, these benefits are provided by automated guided vehicle systems. Currently available systems suffer from the problems of path and vehicle dependence, i.e. the need for a guide wire and the customised nature of the autanatic equipnent which is only suitable for the vehicles with which it is supplied. Future systems will need to be more complex whilst maintaining the ability to suit the smaller, simpler systems. More interfacing with other automatic manufacturing and warehouse equipnent will be needed and the vehicles themselves will need more intelligence. A free-ranging, autonomous, intelligent, automatic vehicle would overcome the present limitations and simultaneously meet the expected future requirements. This thesis describes a research programme which is adequate to develop such a vehicle. This includes the design of a materials handling system which can operate equally well with both simpler wire guided vehicles and the more complex free­ ranging vehicles. The design is based on the roncept of delegated intelligence where the vehicle sub-systems are all controlled by microprocessors. The major advantage of automated guided vehicle systems is the flexibility they give to the materials handling operation and this is a direct function of the intelligence of the system. The provision of intelligence in the vehicle sub-systems has a maJor impact on the flexibility of the complete system. An automatic vehicle has various sub-systems of which the most immediate is steering. The vehicle steering system is designed in a modular manner. A mathematical model of the steerirg system has been developed and validated, and the building of the steering system on the basis of this model means that future system developnent will be for the sensors only and will be rapid. The control of the steering function by a microprocessor gives the system great flexibility, particularly with the use of software controlled manoeuvres.