Research And Design Of Fuzzy Controller For Blank Moulding Of Plastic Blower

Hollow blow moulding(HBM) is molding by pressing blank onto the inner wall of a mould through air pressure. Hollow containers require a minimal wall thickness(WT) of blank for the sake its strength. In the manufacturing process, WT of blank is required to follow the set value exactly and as fast as possible. Additionally, limited points along the outline curve are selected for curve drawing,which demands value insertting between points for a smooth outline.At present WT controller in China are all imported and are of high price and difficult to maintain. So domestic controlling producing means great economic benefit and an advance in HBM industry of China.After a thorough analysis of the methods of wall controlling of HBM system, this thesis estblishes a mathematic model of the power subsystem in HBM, and provides a design for a fuzzy self-tuning PID parameter controller as well as designs for its software and hardware. Th controller, with ARM micro-processor as its core andμC/OS-II real time operation system as its developing platform, can set the value of any blank shape and showes the designed curve in LCD monitor. This thesis also conducts an anlysis of the D/A output continuity of the controller, and proposes that good WT control can be achieved through LCD monitor of the system in the following way: increasing the controlling points of WT just by increasing LCD resolution; and between two neighboring points of the same LCD, by providing controlling data from prediction of curve change tendency to increase the controlling points which will decided by the resolution of D/A conversion, thus curve of parison being continuing.The fuzzy self tuning PID parameter subsystem consists of two parts,namely a PID with tunable parameter and a fuzzy controlling structure. The subsystem is developed from traditional PID controllers, and the fuzzy controller can self-tune the PID parameters--- Kp,Ki,Kd on line in terms of fuzzy inferring with Error e and erraor change rate as its input. This way guarantees controlled objects good properties in static and dynamic states. In order to avoid intricacy fuzzy rule and complex calculation, fuzzy self-tuning PID parameters controller in this thesis is adopted , and consequently only Kp is to be tuned.Meanwhile the fuzzy rule serves as an intelligence function as a result of improvement of traditional controllers with two input-three output.Besides the theoretical research, an experiment and application of the research results in this thesis have been conducted in Chongqing Shuoshan Plastics Factory,...