| This thesis is an important component of national"863"program"splitting processing techniques and equipment of connecting-rod of engine"as well as the national science and technology item for tackling key problem"research and development of precise and efficient fabricating techniques equipment of key parts of automobiles"which gained the outlay sponsor of national ministry of science and technology.Connecting-rod is one of the five key parts (cylinder block, bonnet, crank shaft, connecting-rod and camshaft) in the engine. Connecting-rod needs to work under high frequency with fatigue load, so fabricating and assembling the connecting-rod has high demand. Connecting-rod is a kind of part hard to forge and fabricating, therefore, its fabricating means and techniques draw much attention within China as well as from abroad.Fracture splitting technology of connecting-rod is the newest technique for processing connecting-rod all over the world. The core is to forge the whole firstly and then fabricate a splitting notch on both sides of the inner surface of hole with large head of the half-finish machining connecting-rod to make an area where splitting stress centers and the next step is to perform directional splitting and assemble the bolts in-phase.Different from the traditional processing means, splitting processing techniques cover three core working procedures: processing the splitting notch, performing the directional splitting and assembling the bolts in-phase. How to complete the above three procedures fast, precisely and effectively and reduce the labor is the focus pursued by all the manufacturers. According to this situation, this subject studies and develops semi-automatic product line used for splitting connecting-rod, which firstly integrates the above three core procedures into one product line all over the country. In producing efficiency, it has the high efficiency not owned by independent stand-alone. This product line covers position for burdening and feed, position of laser cutting notch, position of splitting, position of putting the bolts and screwing initially them, position of finally screwing and unloading the parts. The tool for passing connecting-rod among these six positions is the walking beam manipulator. How to achieve the state that while working steadily and fast, each position can also tone precisely to the walking beam manipulator during passing the connecting-rod is the key problem solved by this thesis. Based on studying the working trait of each position, this thesis designs a controlling plan for controlling system of semi-autoimmunization product line used for splitting connecting-rod.This thesis performs profound research on walking beam manipulator, electric hardware connection of the position of cutting notch by laser, acceleration and deceleration controlling computing means as well as the Bus telecommunication controlling of the entire product line. The author mainly completes the following during the research:1. Through the analysis on mechanical system of walking beam manipulator as well as its actions, the author confirms that the walking beam manipulator should cover the movement of three axes and the precision of the position of these three axes should be very high. Based on stable circulation of walking beam manipulator and under the guidance of high cost performance and low comprehensive cost, the author chooses the hardware plan composed of industrial personal computer, motion control cards, servo driving cell and AC servo generator. In addition, the author analyzes the structural trait of the servo system and builds up the mathematical model of the system. In order to achieve the speediness and precision of passing connecting-rod between the walking beam manipulator and each position mainframe as well as the stability for long-term running, based on the discussion on some servo controlling theory , the author designs the arithmetic combining feed-forward control and trigonometric function acceleration and deceleration to control the motion of entire walking beam manipulator. With the feed-forward control, the servo system can gain fast dynamic response and the adjustment of ratio integral coefficient of the position loop in the PID controller can ensure the high precision without overshooting of system orientation. Trigonometric function acceleration and deceleration is an ordinary arithmetic for common servo system. Its speed, acceleration and jerk are continuous. Therefore, the change of the speed during the motioning of the machine tool is smooth without any wobbling or error. Furthermore, the author sets up simulation model of sequential control and precise orientation control between the manipulator and each position and obtains the corresponding simulation result by using Simulink software.2. Through analyzing the mechanical structure as well as motioning process, processing size and precision requirement of laser cutting machine tool used for cutting connecting-rod splitting notch, the author finishes choosing the type of the numerical control system. In addition, the author completes the electric connection design for the comprehensive structure of the system hardware to make the machine own reliable electric control system. In addition, the author confirms that laser cutting machine tool used for cutting connecting-rod splitting notch covers the motion of two axes. Considering the influence of running speed of laser head of laser cutting notch machine tool on the connecting-rod cutting notch quality, in order to ensure that there is on collision between laser head and work-pieces, besides the position of these two axes should be highly precise, acceleration and deceleration control of the axes need arithmetic design. The improved S-type acceleration and deceleration arithmetic is based on S-type acceleration and deceleration often used in top-grade numerical system. Since there are seven stages for S-type acceleration and deceleration arithmetic and refers to many parameters and there are many variation based on different length of the procedure, it is very complex for realization of procedure. Especially, S-type acceleration and deceleration arithmetic is a kind continuous computing means, while the data sampling interpolation of the numerical system is to interpolate according to fixed time interval, that is, a dispersing means, so the author change S-type acceleration and deceleration arithmetic into dispersing means to do the practical computing. Through the cutting notch of connecting-rod by using laser experiment, the engineer practicality of this arithmetic is verified.3. The author designs the hardware connection between PLC and periphery electric system aiming at the requirement for the motion of laser cutting machine tool for connecting-rod splitting notch as well as the protection for the machine tool. In addition, the author analyzes PLC function and completes the defining the input and output points of the machine tool based on the control requirement of the machine tool to realize the signal transmission between the control panel of the machine tool and PLC. In addition, the author makes up the PLC control procedure of this machine tool to make the PLC system precisely and effectively control assistant action of the machine tool and protect the machine tool. The assistant actions mainly include advancing and backing off of the hydro-cylinder, turning on and off of the gas source and radiation and closure of the laser and so on. The protection measures for machine tool mainly cover the collection signal for whether each axis is put in place; the axes will not move while the laser head probes into the inside of the big-end hole of connecting-rod; in certain position, when the connecting-rod is not put in place, the position stops running; if the laser does not send out light, the laser cutting machine tool for cutting the connecting-rod splitting notch stops running and so on. When the above protection happens, the entire product line will send out the corresponding alarming to notify the operator to ensure the safety of the operator as well as the machine tool.4. The author completes the bus-configuration of the entire product line including the bus-configuration between the main station and each position and inner bus-configuration of laser cutting machine used by cutting connecting-rod splitting notch. The function needs to be supervised includes the following: the data collection and treatment during producing; controlling of the producing process; alarming as well as treatment of emergency; diagnosing the malfunction of equipment; mutual telecommunication with superior supervising computer; information demonstration and alarming and diagnosis and analysis on malfunction of equipment. The author applies SLC 500 PLC as the main station to supervise the close switch, photo-electricity switch, PLC signal as well as the controlling signal of servo system on each position inside the product line; as one of the main stations , inner bus-configuration of laser cutting machine used by cutting connecting-rod splitting notch applies Profibus adhered to 802D numerical system, taking charge of supervising close switch, photo-electricity switch, PLC signal as well as the controlling signal of servo system and etc. and transmitting the inner signal to the main station to supervise. Since Profibus and Devicenet bus can not communicate directly, the author embeds the third party telecommunication module Flex I/O in the SLC 500PLC main station. In module Flex I/O, the applicable program is made up according to Profibus-DP contract to indirectly realize the control of SLC 500PLC on Profibus-DP network and the supervision of the main station on each part of the entire product line and thus improve the efficiency and reliability of telecommunication.5. The above operations completes controlling panel design of the system by using human-computer interface of American AB company to help the machine tool own a friendly interface to operate conveniently.After setting all the parameters, the author debugs the semi-automatization product line of the connecting-rod to realize that the product line can automatically seize the connecting-rod, cutting notch by using laser, splitting, initially screw the bolts, finally screw the bolts and unload the material without the interference of human. During the entire process, the structure is stable without any vibration and low noise as well as fast producing time (only 20s). The data tested in practice show that the quality of the connecting-rod completely meets the requirement of practical production.This subject studies and develops the first semi-automatization product line used for connecting-rod with independent intellectual property in China, filling up the gaps in domestic industry and lay foundation for promoting the quality of connecting-rod processing and making up the deficiency of difficulty in changing the kinds of connecting-rod in importing product line, bad universality and high price. Its technical starting point is high with good performance, which has important theoretical meaning and practical meaning in promoting the technical renovation in engine industry of China and pushing the industrialization process of new technology of splitting of connecting-rod.
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