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4.1 Step-by-steps the open system which the electrical machinery drives
This system servo drive mainly is step-by-steps the electrical machinery, the power step-by-steps the electrical machinery, the battery solution pulse motor and so on. Entering sends out which by the numerical control system for instruction pulse, after the actuation electric circuit control and the power enlargement, causes to step-by-step the electrical machinery rotation, through gear vice- and ball bearing guide screw vice- actuation executive component. So long as the control command pulse quantity, the frequency as well as the circular telegram order, then may control the executive component movement the displacement quantity, the speed and the heading. This kind of system does not need the physical location and the velocity feedback which obtains to the input end, therefore called it the open system, this system displacement precision mainly decided in step-by-steps the electrical machinery angular displacement precision, transmission part and so on gear guide screw pitches the precision, therefore the system displacement precision is low.
This system structure simple, debugging service convenient, work reliable, cost low, is easy to reequip successfully.
4.2 The asynchronous motor or the direct current machine drive, diffraction grating survey feedback closed loop numerical control system
This system and the open system difference is: Physical location feedback signal which by position detector set and so on the diffraction grating, induction synchromesh obtains, carries on the comparison as necessary with the given value, two interpolations enlargements and the transformation, the actuation implementing agency, by the speed which assigns turns towards the elimination deviation the direction movement, until assigns the position and the feedback physical location interpolation is equal to the zero. The closed loop enters for the system
Enters for the system complex in the structure compared to the split-ring, the cost is also high, requests strictly to the environment room temperature. The design and the debugging is all more difficult than the open system. But may obtain compared to the split-ring enters for a system higher precision, quicker speed, actuation power bigger characteristic target. May act according to the product specification, decided whether uses this kind of system.
4.3 The direct current servo electrical machinery drives, encoder feedback semi-closure link numerical control system
Half closed-loop system examination part installs in among passes in the moving parts, indirectly surveys the executive component the position. It only can compensate a system ring circuit interior part of part the error, therefore, its precision compared to closed-loop system precision low, but its structure and the debugging all compares the closed-loop system to be simple. In makes the angular displacement examination part and the speed examination part and the servo electrical machinery time a whole then does not need to consider the position detector set installs the question.
The current production numerical control system company factory quite are many, overseas famous company like German SIEMENS Corporation, Japanese FANUC Corporation; Native corporation like China Mount Everest Corporation, Beijing astronautics engine bed numerical control system group company, Central China numerical control company and Shenyang upscale numerical control country engineering research center.
When choice numerical control system mainly is each kind of precision which the engine bed must achieve after the numerical control transformation, actuates the electrical machinery the power and user's request.
Fifth in the numerical control transformation the main mechanical part reequips the discussion
A new numerical control engine bed, must achieve in the design that, Has the high static dynamic rigidity; Movement vice- between friction coefficient small, the transmission is ceaseless; The power is big; Is advantageous for the operation and the service. When engine bed numerical control transformation should meet the above requirements as far as possible. Cannot think the numerical control installment and the ordinary engine bed connects in has met the numerical control engine bed requirements together, but also should carry on the corresponding transformation to the major component to enable it to achieve the certain design request, can obtain the anticipated transformation goal.