Hitachi, Ltd.

Kooetsu Okuyama

Fujio Tajima

Tomokazu Ishii

Hideki Tanaka

Kenji Toki

Takao Terayama

Kazuo Sakai

Nobuyuki Kaku

Shigemitsu Higuchi

Kenji Ogiro

Taichiro Yamashita

Kenmei Masuda

Fumio Takeda

Takayuki Munemoto

Fukuyasu Abe

Shigeyuki Kobata

Masaru Orii

Tadashi Honzawa

A tape cartridge is received into one end of an information recording and/or reproducing apparatus conforming to an 8 inch Form Factor Size. A first reel is held inside this tape cartridge, and a tape wound onto this first reel is extracted from a cartridge including the first reel and threaded by a simple pivotal motion of a tape threading arm, and wound onto a second reel disposed at the other end of the information recording and/or reproducing apparatus. The pivotal center of the tape threading arm and a recording head are disposed at opposite sides respectively with regard to a line joining a first and second reel axes to facilitate a compact overall construction. Tape guides formed into cylindrical rollers and the recording head are disposed on the inner side of the trajectory of the tape threading to transfer the tape smoothly. The tape guides and the recording head may be arranged substantially in line. Also, the tape guides next to the recording head may be fixed rollers.

Information recording and/or reproducing apparatus having a tape

As a method of increasing the storage capacity of a magnetic recording and reproducing apparatus for recording and reproducing information to and from a magnetic tape in a cartridge, there is a helical scan recording method in which the magnetic tape is diagonally wound around a drum which rotates a magnetic head. With an apparatus adapted to this method, the disposition of the cartridge and the take-up reel for taking up the magnetic tape on the same plane arises a necessity of considerably bending the magnetic tape at the drum portion and, accordingly, the magnetic tape is damaged. In order to prevent the damage of the foregoing type, the tape passage surface from the cartridge to the drum and the tape passage from the drum to the take-up reel are formed by an angle at which the direction in which the magnetic tape is moved is changed due to winding of the magnetic tape around the drum so that the magnetic tape is not bent excessively. A threading device capable of three-dimensionally controlling the position of the magnetic tape in accordance with a predetermined tape passage is provided for the apparatus structured as described above. The threading device is formed by a link mechanism to be moved along the locus of a cam groove so that the three-dimensional position control can be performed.

Magnetic recording and reproducing apparatus

A servo-mechanism control system calculates an operation value to be applied to a control object from a desired value of a control output and a detected control output of the control object, and drives the control object based on the calculated operation value so that the control output becomes equal to the desired value. The control system is less sensitive to the variation of characteristics of the control object and disturbances, and stable control is accomplished by a simple circuit arrangement. A mathematical model and its inverse function, which are based on the assumption that the control system is not subjected to the variation of characteristics of the control object and disturbances, are used to calculate a model-based control output. In error of the operation value is calculated from the difference between the model-based control output and the detected control output by using the inverse function of the mathematical model, and the operation value applied to the control object is modified by subtracting the error from the calculated operation value. Alternatively, the model-based operation value is calculated from the detected control output by using only the inverse function of the mathematical model, and the operation value is modified based on the difference between the model-based operation value and the calculated operation value.

Control method and apparatus for a servo- mechanism

In a servo system using a discrete signal relative to a position, a time delay and an error upon detecting a speed due to lack of positional information are eliminated to achieve a positioning to a target position in a short time. A pulse signal X.sub.P relative to a position is used to establish synchronization with an observer which is adjusted to match with an actual apparatus comprising a load, a motor and so on, and an estimated speed value or an estimated position value generated by the observer are used to determine an operating signal for the servo system.

Servo control method for a servo system

A servo-mechanism control system calculates an operation value to be applied to a control object from a desired value of a control output and a detected control output of the control object, and drives the control object based on the calculated operation value so that the control output becomes equal to the desired value. The control system is less sensitive to the variation of characteristics of the control object and disturbances, and stable control is accomplished by a simple circuit arrangement. A mathematical model and its inverse function, which are based on the assumption that the control system is not subjected to the variation of characteristics of the control object and disturbances, are used to calculate a model-based control output. An error of the operation value is calculated from the difference between the model-based control output and the detected control output by using the inverse function of the mathematical model, and the operation value applied to the control object is modified by subtracting the error from the calculated operation value. Alternatively, the model-based operation value is calculated from the detected control output by using only the inverse function of the mathematical model, and the operation value is modified based on the difference between the model-based operation value and the calculated operation value.

Control method and apparatus for a servo-mechanism

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Tsuchiura, Japan

Kooetsu Okuyama