Numerical control method and apparatus therefor

A numerical control apparatus comprising:

• a machine-control processing sequence that includes a machining-program analyzing unit, a feeding speed controller, an instruction generating unit, a programmable-logic control unit, and an instruction-output determining unit that receives a check result from a preceding-check processing sequence and stops a machine before the machine reaches a collision detection position when a collision is detected, and performs an actual machine control;
• the preceding-check processing sequence that includes a machining-program analyzing unit, a feeding speed controller, an instruction generating unit, a programmable-logic control unit, a collision checking processor that checks a collision possibility by using shape data and delivers a check result to an instruction-output determining unit of the machine-control processing sequence, and an instrumental-device-signal simulating unit that simulates a response signal of a device allocated to an instrument other than an NC control axis, and performs a collision possibility check ahead of an actual machine control by the machine-control processing sequence;
• a monitor display unit that simulates by using shape data a state of machining with an actual machine, and sequentially displays a simulation on a screen;
• and
• a control-state synchronizing unit that matches a state of the preceding-check processing sequence with a state of the machine-control processing sequence during a period from when a machine stops until when the machine restarts an operation.