Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
129 words
A positioning servo mechanism comprising an electrical actuator driven in response to algebraically summed signals representing commanded position, actual position, and velocity, and in which the velocity signal is obtained by adjusting a coarse velocity signal produced by integrating a signal representing the actuator current, characterised in that the servo mechanism includes a first integrator (38) with its output amplified by a variable gain amplifier (39) to generate the coarse velocity signal, a second integrator (42) integrating the coarse velocity signal to give a coarse position signal, comparison means (45, 47, 49) for comparing the coarse position signal with a reference signal (46), and means (54) for adjusting the gain of the variable gain amplifier (39) in response to the comparison so as to adjust the coarse velocity signal.
Claim 2
Dependent Claim
129 words
A positioning servo mechanism comprising an electrical actuator driven in response to algebraically summed signals representing commanded position, actual position, and velocity, and in which the velocity signal is obtained by adjusting a coarse velocity signal produced by integrating a signal representing the actuator current, characterised in that the servo mechanism includes a first integrator (38) with its output amplified by a variable gain amplifier (39) to generate the coarse velocity signal, a second integrator (42) integrating the coarse velocity signal to give a coarse position signal, comparison means (45, 47, 49) for comparing the coarse position signal with a reference signal (46), and means (54) for adjusting the gain of the variable gain amplifier (39) in response to the comparison so as to adjust the coarse velocity signal.
Claim 3
Dependent Claim
51 words
A positioning servo mechanism according to claim 1 further characterised in that it includes means (70) for generating an accumulative error compensating signal and supplying it to the first integrator (38) so as to compensate for accumulative errors and enable the variable gain amplifier (39) to remain within its dynamic range.
Claim 4
Dependent Claim
50 words
A positioning servo mechanism according to claim 2 further characterised in that the means (70) for generating the accumulative error compensating signal includes means (72) for deriving the difference between the instantaneous value of the signal from the gain adjusting means (54) and a previously stored value of that signal.
Claim 5
Dependent Claim
40 words
A positioning servo mechanism according to any previous claim further characterised in that the gain adjusting means (54) comprises a binary counter arranged to count up or down in response to a signal from the comparison means (45, 47, 49).
Claim 6
Dependent Claim
106 words
A positioning servo mechanism according to any preceding claim characterised in that the actuator (21) is coupled to a carriage (19) carrying magnetic heads (18, 24) of a magnetic disk memory, the position signal is generated by a cylinder detector (27) capable of detecting magnetic track crossings, and that the trackcrossing signal from the cylinder detector (27) initiates the operation of a sample-and-hold circuit (47) and resets the second integrator (42), so that at each track crossing the coarse position signal representing calculated track spacing may be compared with a reference signal (46) representing actual track spacing to enable the coarse velocity signal to be adjusted.