The research concerns the design and implementation of mechatronic systems to assist in the operation and control of a sugar cane harvester. Two functions were chosen for attention, the primary separation system, and the ‘topper’ that discards the leafy crown. Although these operations are given low priority by the operator of the harvester, their optimisation is of particular significance to the industry. Optimum separation requires a fine balance between discarding ‘trash’ that would contaminate the quality of the cane billets and losing good sugar-bearing material through over cleaning. Poor control of the topper can create extra load for the separation system and cause it to operate at a low efficiency with high loss. Alternatively it can cause a length of sugar-bearing cane stalk to be lost before it even enters the harvester system at all. A variety of mechatronic techniques were explored, that addressed the problem of providing useful data directly from the harvester functions and the electronic instrumentation to allow the data to be collected in a useful form in real-time. Computer control issues were also investigated, to make best use of the data stream. Novel acoustic transducers were introduced to the sensory separation system to provide a signal that indicated material striking the fan blades. A rotary transformer was required to allow transmission of the signal, and a signal interface system was implemented to record the returned data. Many real-time time-series analyses were conducted, and from these a suitable algorithm to extract an impact signal was developed. This system was assessed under harvesting conditions with results that confirmed its ability to quantify the amount of cane lost from the harvest. An investigation was conducted to detect the optimum topping height on a sugar cane stalk. The techniques considered both the internal and external attributes of the stalk, and a method was selected to measure the sugar concentration with a chemical sensor. An important design parameter was that the sensor must operate on the harvester in real time. The novel refractometer worked well in laboratory conditions, yielding repeatable and accurate results. The field environment complicated the application of this system, however this was partly overcome with introduction of a custom sample-crushing mechanism. This device provided the necessary juice sample from a selection of the topped cane stalks. The complete sampling and measuring mechanism operated well on cane stalks, and returned encouraging results. Both sets of data returned useful information regarding the operation of the particular harvester operations. The control of either the separation system or the topper requires careful balancing, and novel control techniques that consider the ergonomics for the operator are discussed. These include visual indication devices through to automatic control algorithms. With the integration of mechatronic techniques into the functioning of the sugar cane harvester, the overall efficiency of many of its functions may be improved, and the operator’s task may be greatly simplified. The ultimate objective is to maximise the yield with an improved level of harvested and separated cane.

The aim of this thesis is to design a kilowatt three-phase step-down rotary transformer for a permanent magnet DC motor. The permanent magnet DC motor has an on-rotor drive system, and therefore requiring a power supply that can transfer power to its drive unit without mechanical contact. The rotary transformer has a detached magnetic coupling structure that qualifies it as a potential method for the wireless power transfer. This thesis studies the rotary transformer as a static device, focusing on its core loss. By using a transient finite element analysis of COMSOL Multiphysics and an iron loss prediction model, the rotary transformer was optimized in terms of efficiency and power density for the on-rotor drive system through proper material selection and geometry exploration. After this, a mechanical design, which based on a literature review of the influences of manufacturing processes on electrical steels, was proposed for realizing the core fabrication and the rotary transformer assembly. The results show that the rotary transformer can step down 400 V/50 Hz three-phase voltage to 13.15V in a Delta-wye connection and output 1.17kW power over an air-gap of 0.3mm with 95.94% overall efficiency. The proposed mechanical design enables the transformer to minimize the core loss and the manufacturing cost. Without using resonant inductive coupling, this transformer design simplifies the power supply for the motor, thereby decreasing the motor manufacturing and maintenance cost.