Automatic cutter compensation for contouring control systems

Claim 1

In a contouring control system for producing relative motion along a commanded path between a cutting tool and a workpiece, the system including (1) input information means for commanding the speed of said relative motion and first and second directional components of the commanded path to be followed along respective axes, (2) a master clock oscillator for synchronizing system operation, (3) a velocity command generator coupled to the input information means and the master clock oscillator for producing contouring velocity pulses at a rate indicative of the speed of said relative motion, (4) a contouring function generator coupled to the velocity command generator and the input information means for resolving the contouring velocity pulses into the first and second components of pulses having respective rates which indicate the direction of the commanded path relative to axes, (5) compensating information input means for indicating the required amount of compensation resulting from deviation in cutting tool dimensions, (6) a compensating function generator coupled to said velocity command and to said compensating information input means for resolving said contouring velocity pulses into first and second components of pulses having respective rates indicative of the information received from said compensating information input means, said compensating function generator responsive to said compensation information input to resolve the magnitude of said input into first and second directional components along respective axes, said contouring function generator and said compensating function generator both changing the rates of their respective pulses relative to changes in the angle of the commanded path, (7) means for setting said contouring function generator and said compensating function generator in initial and similar conditions, (8) means coupled to said contouring function generator and said compensating function generator for combining said first components of pulses to produce first result pulses for effective movement along one of said two axes and (9) means coupled to said contouring function generator and said compensating function generator for combining said second components of pulses to produce second resultant pulses for effecting movement along the other of said two axes, the improvement comprising: a. a third function generator operatively connected to said compensating function generator and the master clock oscillator for generating first and second pulse trains respectively proportional to said first and second directional components along respective axes; b. a fourth function generator operatively responsive to said input information means and to the master clock oscillator for generating third and fourth pulse trains respectively proportional to the first and second directional components of said input information; c. comparison means operatively connected to said third and fourth function generators for comparing the angle represented by said first and second pulse trains with the angle represented by said third and fourth pulse trains; and d. modifying means operatively connected to said comparison means for modifying the information stored in the compensating function generator whenever the output of said comparison means indicates that the angle represented by said first and second trains is not equal to the angle represented by said third and fourth pulse trains.