Direct drive motor system

A direct drive moto system comprising

• motor means of an inductive type comprising a stator, a rotor and a coil;
• rotation detecting means for detecting rotation of said rotor;
• position control means for obtaining a first difference between an instruction signal of a rotational position of said rotor and a detection signal from said rotation detecting means and for outputting a control signal using a tertiary servo system relative to said first difference;
• speed control means for obtaining a second difference between an output signal from said position control means and a detection signal from said rotation detecting means and for outputting a control signal using said second difference;
• driving circuit means for detecting an exciting current which passes through said coil, and for obtaining a third difference between a detection signal of said exciting current and an output signal from said speed control means, and for controlling said exciting current by using said third difference;
• tuning means for adjusting said tertiary servo system and said position control means;
• and
• stopper means for stopping said motor means, said stopper means comprising comparison means for comparing rotational speed of said motor means with a reference value, and for outputting a signal corresponding to said comparison, connection switch means, means,responsive to an output from said comparison means, for shorting said coil of said motor means when rotational speed of said motor means is lower than said reference value, and means, responsive to said output from said comparison means, for connecting said coil of said motor means to a parallel circuit comprising a resistor and a capacitor when rotational speed of said motor means is higher than said reference value.

A direct drive motor system comprising

• motor means of an inductive type comprising a rotor disposed on an outside thereof, a stator disposed on an inside thereof, and a coil;
• rotation detecting means for detecting rotation of said rotor of said motor means, and for outputting a position detection signal and a speed detection signal;
• position control means for generating a position control signal, said position control means comprising a gain table for recording characteristic frequency, load inertia value, and most suitable control parameter value corresponding to said characteristic frequency and said inertia value,and test signal generating means for generating a known test signal as a position instruction signal, means for obtaining a first difference between said position instruction signal and said position detection signal, and means comprising tertiary servo system and responsive to said first difference for outputting said position control signal;
• speed control means,responsive to a second difference between an output signal from said position control means and said position detection signal,for outputting a control signal, said speed control means comprising a digital to analog converter, and means, responsive to a signal from a tuning means, for setting gain of said digital to analog converter;
• driving circuit means for detecting an exciting current passed through said coil of said motor means, said driving circuit means comprising current detecting means, including a small signal isolator, for obtaining a third difference between said etection signal of said exciting current and an output signal from said speed control means and means for controlling said exciting current depending upon said third difference;
• and
• said tuning means for tuning said tertiary servo system of said position control means, said tuning means comprising a characteristic frequency setting switch, means for setting in said setting switch characteristic frequency and load inerti in a plurality of steps within a predetermined range, means for controlling said setting switch to read out a most suitable control parameter from said gain table depending on at least one of said set characteristic frequency and load inertia to control the rotation of said motor portion, a load inertia setting switch, and means for obtaining said position control signal output from said position control means when said test signal is applied to said position control means.