Research And Application On The Problems Of Loading Weight Independently And Weight Exchange Of Dead Weight Force Standard Machine

The manufacturing occupies very big specific gravity in the country economy, but it can not get away from the detection of the force, detecting the force need to use the force standard machine. The force standard machine is the measure instrument for detecting the characteristics of load cells. The dead force standard machine occupies obvious advantage at the accurate degree and the stability aspect of the force, and has the function that other force standard machine difficult to substitute.The structure of loading weight of the traditional dead force standard machine is very complex, the time that load and unload weight needed is long and the progression of the load is few, otherwise the work process of the equipment hasn't realized automatic and visualized. So the article takes the force standard machine of loading weight independently for the object of research, put forward the principle and the method of loading weight independently in the country for the first time, in succession did the theoretic analysis and validating of experimentation for the control of load and unload weight and the control of exchanging weight.This article analyzes the loading weight independently of force standard machine in detail as follows at a few aspects, and put forward the viable method which can resolve the key problem and applied in the practice, the main contents includes:Ⅰ. Discusses the methord of the structure implement and the work principle of the force standard machine of loading weight independently in detail;The structure of the force standard machine of loading weight independently is simple and practical. The main mechanical parts of the machine includes: The weights - criterion of force detection, the bracket (the driven piece of the cam)–the device of loading and unloading the weights, the fixed cage - lays aside the weights installment, suspending device - equipment of bearing the inspecting weights, in addition the preventing swing device–equipment of preventing the swing of the suspending device. This article analyzed the upwards parts in detail, included the function of each part, the whole test process and the carrying out principle etc..Ⅱ. Analyzes the control process and realization methord of loading and unloading the weight independently of the force standard machine; The force standard machine of loading weight independently uses the individual driving structure to implement the independent loading and unloading action of every weight, it make the weights on the machine can be assembled arbitrarily and individually or grouped load force simultaneously on the sensor. As a result the time of loading and unloading weight can likely be shortened, the range of detecting the force can be extended and the load method can be assembled more freely.The electromotor drives the driven of cam (the bracket) to rise and drop, then the bracket drives the weight to finish the movement of loading and unload, the electromotor and the cam decide the movement rule of the bracket. The start and stop of the movement adopt the computer to control the PLC, and finished by the approach-switch emit the signal of approach. The electromotor uses synchronism electromotor which has the invariableness rev, no over-current phenomenon and so on. The invariableness rev can promote several brackets of one weight to move synchronously, no over-current phenomenon can make the control device of theelectromotor to recede the protective requirement. As the power of the electromotor is less, we can use the export point of the PLC to drive it directly, therefore predigest the structure of the control system.Ⅲ.Analyzes the method and its control problem of exchanging weight in detail for the force standard machine of loading weight independently;The load method of exchanging weight has several advantages, such as the number of the weight is few, the range of detecting is wide and the volume of equipment is small. But the process of this load method should not to affect the work capability of equipment especially the definition of detecting. Therefore the key problem of this method is how to guarantee the stable of the force during the process of loading weight, namely the wave of the force should be small and satisfy the require for time during the process of loading weight.If the effect of exchanging weight is equal to the process of straight loading weight, the method of loading weight through exchanging weight will not affect the result of detection. Therefore, the article establishes the mechanics model and control model for the implement of control on the base of research the mechanics process of exchanging weight. The experiment shows that the research and the model are all right. The article also put forward the method of adding and unloading weight through estimate the parameter early and open cycle control aim at the process of exchanging weight, it shows that the method is viable and effective, also has the character of simple and credible. The phenomenon of reverse load during the process of exchanging weight can be effectively reduced up to be eliminated through changing the exceeded forward time of loading or unloading weight.Ⅳ.Analyzes the vibration of the movement and the restrain the wiggle of suspending device during the force standard machine of loading weightindependently loading and unloading the weight;The article establishes the mechanical model of separating system that used to defend the impact of outside force on base of analyzing the movement of loading and unloading the weight independently, also analyzes the effect of hanger system of force standard machine upon measurement precision. The examination proved that the analysis and model are all right, the method of preventing swing and restrain the wiggle is simple and effective.Ⅴ. Analyzes the detecting software of the force standard machine;The article analyzes the direct operation interface and the man-machine interface in detail, the interface of the force standard machine chose two kinds of customer interfaces to add mutually, each way that take bureau chief, can make to operate interface to use in brief and easily and visible. Realize the serial communication between the PC and several outside device through the control of MSCOMM that VC++ afforded. Realize the PC controlling several outside device at the real time. The detecting software work credibility in actual application, it proved the method that be used is valid and viable.All of these are the emphases in this thesis. Analysis ways and solving measure applied in it are applicable for both the 10KN force standard machine of loading weight independently and other devices similar.