摘要:
A voice coil driven positioner is provided for positioning the magnetic head of a tape drive relative to the tape of a removable tape cartridge. The head positioner includes a low-mass carriage that supports the head on one end and the voice coil on an opposed second end. A low friction guide mechanism guides the carriage along a precision movement path that carries the head across tracks of a supplied multi-track tape and simultaneously carries the voice coil through a flux field generated by a stator. A movable portion of a position detector is attached to the carriage and located within the hollow of the voice coil for reciprocating into a hollow passageway of the stator together with reciprocation of the voice coil into another hollow of the stator. A fixed portion of the position detector is attached to the stator and located compactly within the hollow passageway of the stator. A programmable lookup table converts measurement signals output by the position detector into pre-calibrated, head-position indicating signals. A platform is provided on the carriage for mounting an interferometer prism used during calibration.
摘要:
A voice coil driven positioner is provided for positioning the magnetic head of a tape drive relative to the tape of a removable tape cartridge. The head positioner includes a low-mass carriage that supports the head on one end and the voice coil on an opposed second end. A low friction guide mechanism guides the carriage along a precision movement path that carries the head across tracks of a supplied multi-track tape and simultaneously carries the voice coil through a flux field generated by a stator. A movable portion of a position detector is attached to the carriage and located within the hollow of the voice coil for reciprocating into a hollow passageway of the stator together with reciprocation of the voice coil into another hollow of the stator. A fixed portion of the position detector is attached to the stator and located compactly within the hollow passageway of the stator. A programmable lookup table converts measurement signals output by the position detector into pre-calibrated, head-position indicating signals. A platform is provided on the carriage for mounting an interferometer prism used during calibration.
摘要:
Control of a d.c. motor (14), which may drive for example a 'daisy' print-wheel, is achieved using a micro-computer (18). A movel algorithm which uses the micro-computer in an unconventional way permits the construction of a system with a minimum of additional circuitry and with a very fast response time. A striped disc (10) coupled to the motor (14) and sensed photo-electrically (A, B, H) provides position status information. An 8-bit status byte is produced, with 4 bits (a, b, a', b') representing present and past position status and indicative of clockwise, anticlockwise or no movement. The 8-bit status byte is used as a pointer into a look-up table of addresses of action routines. A loop of only four instructions can perform the input and decode functions. As the target position is approached the motor is switched to slow mode operation in which the motor decelerates for a fixed interval and then accelerates until the next incremental move is made.
摘要:
Bei einem Verfahren zum positionsgenauen Triggern eines wahlweise aktivierbaren Maschinenteils (12), das entlang von zumindest einer Bewegungsachse (18) relativ zu einem Werkstück (22) verfahren wird, werden Ortspulse (32) mit Hilfe eines Inkrementalgebers (28) erzeugt, wobei die Anzahl der Ortspulse (32) einer Ortspulsfolge (30) repräsentativ ist für die Verfahrposition des Maschinenteils (12). Das Triggersignal (54) für das Maschinenteil (12) wird erzeugt, wenn die aktuelle Ortspulsanzahl einer definierten Pulsanzahl entspricht. Vorzugsweise findet der Vergleich der aktuellen Ortspulsanzahl und der definierten Pulsanzahl getrennt von einem übergeordneten Antriebsregelkreis (38, 46) statt. Besonders bevorzugt ist es, wenn der Vergleich der aktuellen Ortspulsanzahl und der definierten Pulsanzahl in einem Vergleicher stattfindet, der auf einer Schnittstellenkarte (48) einer Recheneinheit (36) angeordnet ist, wobei der Antriebsregelkreis mit einem Regler in Form eines Reglerprogramms (46) realisiert ist, das von dem Prozessor (38) der Recheneinheit (36) zyklisch abgearbeitet wird.
摘要:
A system for numerically controlling a device such as a machine tool employs a general-purpose motor (11) in a part thereof, instead of a servo motor. In this system, the current position of a shaft (10) which is driven by the general-purpose motor (11) is detected (14, 9) and is compared with a command value within an NC program. When the current position is close to the command position, a brake signal (MBR, BR) is output in order to apply a brake to, for example, the general-purpose motor (11), and the supply of rotational signals (MCW, MCCW) to the general-purpose motor (11) is inhibited to stop the general-purpose motor (11) at the command position.
摘要:
A drive mechanism comprising a power driven screw (16) and a nut means (17) co-operating with the screw includes a device for the correction of backlash prevailing between the screw and the nut means. The correction takes place electronically by modification of two pulse trains (A, B) which are generated by a pulse generator (19) which is synchronized with the movement of the screw. Out of the two pulse trains information as to position and direction of movement is derived for a movable unit (11), which is connected to the nut means and which, for instance, can be a printing unit in a printer or a typewriter. A measured or estimated value of the backlash is digitally stored with a resolution of one quarter of the period of the pulse trains. This resolution is four times the smallest distance through which the movable unit can be moved. The two pulse trains (A, B) are combined in a signal modifying device (21) in four different ways and in a selected one of two opposite successions to perform displacement of a predetermined flank (8) in one (B) of the pulse trains as many steps of one quarter of the period as correspond to the stored backlash value and in a direction corresponding to the selected succession.
摘要:
Procede de mesure avec un dispositif de commande numerique possedant des organes (107) permettant de calculer et de stocker la difference entre le nombre d'impulsions de reactions produites chaque fois qu'une unite mobile se deplace sur une distance predeterminee et le nombre d'impulsions d'instructions (Pc) produites par un distributeur d'impulsions (103) pour la commande d'un moteur de maniere que la difference soit egale a 0. Ce procede comprend les etapes consistant a compter les impulsions detectees (Mp) produites par un detecteur (210) au moyen de l'organe de calcul (107), a donner la valeur comptee lue par l'organe de calcul (107) au distributeur d'impulsions (103), a calculer et a stocker la difference entre le nombre d'impulsions distribuees (Ps) produites par le distributeur d'impulsions et le nombre (Mp) d'impulsions detectees par l'organe de calcul (107), a lire le contenu de l'organe de calcul (107) chaque fois qu'un nombre d'impulsions distribuees egal a la valeur comptee est produit et envoye au distributeur d'impulsions, et a calculer la somme totale des valeurs comptees lues dans l'organe de calcul (107), ce qui permet de compter le nombre total d'impulsions detectees.
摘要:
An example method for controlling a carriage of a printing device is described. In one implementation, a target velocity value that satisfies a sharpness threshold is filtered by a processor resource of the printing device, a feed forward term is generated using a continuous model applied to the filtered velocity input using a plurality of electromechanical parameters, a feedback term is generated based on a difference between an expected pulse-width modulation (PWM) profile and an actual PWM profile, and a voltage to be provided to a motor of the carriage is adjusted based on the feed forward term and the feedback term.