Abstract: A current sensing module for use with a variable speed AC motor control drive system for use with devices such as treadmills and including a module to sense the current of pulse width modulated signals provided to an AC motor wherein the current sensing module includes a fast sense circuit to sense excessive current conditions in the pulse width modulated signals and a slow sense circuit to sense average current values in excess of desired values over a predetermined period of time to protect the AC motor from damage caused by the increased frictional resistance to the rotation of the walk belt on the treadmill deck as the walk belt and treadmill deck wear out.

Abstract: A digital locked loop uses feedback to maintain an output digital signal in a specific digital relationship with a reference digital signal. The digital locked loop can lock an input digital signal according to a reference digital signal by using a digital counter, a resister and an arithmetic logic circuit instead of a phase locked loop and a frequency locked loop in motor drive integrated circuit for permanent magnetic brushless DC multi-phase motor drive applications. The circuit is designed not to use a voltage-controlled oscillator VCO and can be extended to broader applications such as digital data communications, digital image processing, and in the multi-media industry.

Abstract: In order to give piano-like key touch to a player in an electronically sound producing mode, a keyboard incorporated in a musical instrument is linked with key action mechanisms associated with hammer mechanisms, and a stopper blocks the hammer shanks before the hammers strike the strings so that noises are not mixed with synthesized tones.

Abstract: A motor control system for individually feedback-controlling a plurality of servomotors includes: a plurality of motor drive devices for converting DC power into AC power to drive the servomotors; current detecting devices for detecting the current value of the AC current to feed it back to the motor drive devices; and an A/D converter for converting the output signals of the current detecting devices into a digital signal. The motor drive devices, current detecting devices and A/D converter are accommodated in a casing for a group of servomotors, and the output terminals of the current detecting devices in the casing are connected in parallel to the input terminal of the A/D converter, so that the A/D converter is used for all of the current detecting devices in the casing. The resultant motor control system is small in the number of components, and accordingly in the number of wiring conductors, and is simple in construction and accordingly in adjustment work.

Abstract: Apparatus for compensating for positioning, pointing and/or orientation errors caused by deflections of structural members and components of a high performance machine or device and/or for reducing vibration inputs to such machine or device and/or for micro-positioning such machine or device so as to improve the operational performance of such machine or device. The apparatus utilizes one or more active-type actuators, such as piezoelectric ceramic type actuators, which are arranged in a predetermined manner relative to the machine or device. A servo control device operating in accordance with a predetermined algorithm may be utilized for controlling the actuators or, alternatively, the apparatus may operate in an open loop manner.

Abstract: A tone setting device includes an operating section for selecting segments in combination from among various segments of exciting mechanisms and structures employed in plural types of musical instruments, and a data supply section supplies tone setting data, corresponding to the combination of the selected segments, as data for setting a characteristic of a tone. By thus combining segments of desired musical instruments, a free tone selection can be conducted easily in such a form where the selected tone color can be readily recognized by a human operator. Also, a plurality of parameters are allocated to a single operator so that the parameters can be simultaneously adjusted by respective unique amounts of change based on operation of the same operator.

Abstract: A MIDI playback system is described in which a sequencer is characterized by: logic for generating a sequence of events, the sequence comprising groups of events, each group comprising events to be executed within a first time interval, the groups being separated in the sequence by marker events for indicating the time intervals, the sequencer being arranged to send the sequence of events together to a synthesizer. A synthesizer is described comprising storage means to receive and store the sequences of events; logic for reading an event from the storage; and logic for determining if the event is a marker event, the synthesizer being arranged to wait, if the event is a marker event, a time equal to the first time interval before reading another event from storage. Using this arrangement, the sequencer is no longer required to schedule the MIDI commands precisely on time and therefore the timing services that a software implementation of such a sequencer might ask from a computer system are reduced.

Abstract: An improved motor for driving a variable-speed fan used, for example, to prevent overheating of electronic equipment, features an electronic controller which sends current pulses through the stator winding(s) of the motor, and varies the slope of trailing edges of these pulses in accordance with at least one sensed operating parameter of the motor, such as temperature of the power semiconductors which control the motor current. The slopes are steepened at high motor speeds to reduce electrical losses, and flattened at low motor speeds to minimize noise. Another feature of the improved motor provides for fail-safe, high-speed operation of the fan when the sensed value of the operating parameter is implausible, for example when a lead from a temperature-dependent sensing resistor breaks. In a preferred embodiment, a bridge circuit is used, which includes a transistor in one diagonal of the bridge circuit.

Abstract: A circuit and method for driving a brushless sensorless direct current (DC) motor (2), using the steps of: at the beginning of each phase, driving the motor in PWM mode; monitoring the duration (Tc) between successive zero-crossings of the back electromotive force (BEMF), and accordingly predicting the next zero-crossing; and before the next predicted zero-crossing, switching to a linear driving mode only until the actual zero-crossing of the BEMF.

Abstract: A system for carrying out offline programming of an industrial robot takes steps to improve upon a known, approximate kinematic model of the robot. By placing three measuring devices within a robot workspace and calculating an approximation of their coordinate frame within that of the workspace, accurate positioning of the measuring devices is not required. This can be achieved by a multivariable search method performed by a computer.

Abstract: The invention relates to a device for the automatic control of a windscreen wiper motor. The device has a moisture sensor which emits a signal depending on the moisture on the windscreen or another point on a motor vehicle so that this signal to some extent produces an analog reflection of the moisture varying in time. The output signal of the sensor is evaluated in such a way that it is continuously compared with a threshold value which can be altered. Every time this threshold value is reached or exceeded by a pulse-like change in the sensor output signal, this event is counted. After a given number Z of such events the windscreen wiper motor is switched on.

Abstract: The brushless motor has: a field unit having a rotor permanent magnet (12); three-phase driving windings (20A, 20B, and 20C) of the stator; driving transistors for supplying a power to the driving windings; a driving command unit (43) for generating sinusoidal driving command signals; and a driving unit which supplies to the driving windings sinusoidal driving currents in accordance with the driving command signals. The driving command unit (43) consists of: a time interval measurement device (42) which measures timing intervals from a pulse signal of a rotation detector (41), the timing intervals being inversely proportional to the rotational speed of the rotor; and a driving command generation unit (43) which changes an estimated electric angle at time intervals responding to the measurement result of the time interval measurement device thereby to generate the sinusoidal driving command signals corresponding to the estimated electric angle.

Abstract: To effect failure detection and communication between the modules in a modular control system for an electrically driven vehicle in which modules are interconnected by a serial data bus, one line of the serial bus may be biased high or low by modules of the system when a fault is detected. This is detected by a kill system of the modules to which disable safety related functions of each module are applicable. Modules other than the remote control module can include wake up circuitry which supplies power to the modules at start up, or deactivated modules, when the data line is biased high. The modules preferably operate as finite state machines with each module storing in its memory network variables required for the operation of that module. The network variables include the state of other modules, external demand signals, and measured variables of the system.

Abstract: A start-up circuit for a sensorless, brushless DC motor modifies a conventional start-up circuit to include an intermittently-accelerated-rate clock generator for supplying a clock signal intermittently accelerated in rate to a shift register that is connected as a ring counter for selectively generating three-phase commutation signals during start-up and six-phase phase commutation signals during running. The intermittently-accelerated-rate clock generator facilitates the start-up circuit increasing the magnitude of a back electromotive force by adjusting the rate of a starting clock during start-up of the motor, so as to be capable of both a normal start-up with a normal-rate clock signal and an accelerating start-up with an accelerated-rate clock signal. This permits a stable and rapid start-up without need for a microprocessor or complicated circuitry.

Abstract: A plug-in module receives both primary and alternate power via mating connectors on the module and on the backplane. Multilevel connectors are used so that a module being inserted first receives alternate power and ground before primary power and signal connections are made. The initial connect to the alternate power supply directs the transient current to the alternate power supply through an isolating PN junction diode having a forward bias voltage drop of about 0.8 volts. When the module is fully inserted, the module is connected to both the primary and alternate power. Within each module the associated electrical load is now connected directly to the primary power bus. To prevent transient currents produced by the hot insertion of other plug-in modules from affecting the voltage level on the power bus, the primary voltage supply is connected to the primary power bus via a Schottky diode having a forward bias voltage of approximately 0.4 volts.

Abstract: In a computer apparatus including an enclosure and a direct access storage device mounted within the enclosure, a mounting apparatus for the direct access storage device including: a plurality of a relatively rigid shock isolators and at least one stress sensor mounted in series with are of said shock isolators and disposed between the enclosure and the direct access storage device. The enclosure may include a user frame and the mounting apparatus may be disposed between the direct access storage device and the frame. There may be one stress sensor for each of the shock isolators. The shock isolators may be coupled to the direct access storage device. Each stress sensor may include a piezoelectric element. Preferably the shock isolators are rigid enough so that the resonant frequency of said mounting apparatus is at least 800 Hz, but can be 800 Hz or higher.

Abstract: A drive assembly comprises a DC electric motor and an integrated charger/controller/regenerator which includes a power module, a step-up module and a control circuit. The input of the power module is connected to an electric power source during charging, and to the DC motor during regenerative braking. The input of the step-up module is connected to the power module, and the output is connected to the battery. The control circuit includes a switch, and has three modes of operation: driving, regenerative braking and charging. During driving, the switch connects the battery to the power module input and the power module output to the DC motor. During regenerative braking, the switch connects the DC motor to the power module input and the power module output to the step-up module input, and the step-up module output charges the battery. During charging, the switch connects the power module output to the step-up module input, and the step-up module output charges the battery.

Abstract: A single-motor drive for an open-end spinning machine, the motor being in the form of an axial field motor with a magnet/gas bearing supporting the rotor with a gas cushion, includes a gas monitoring arrangement which will detect a disruption in the gas supply, and responsive to the gas disruption, a device for braking the rotor is connected with the circuit via a switch. The braking device, which includes a ballast resistor, is set for reducing the rotational speed of the rotor in a manner whereby when the rotor bearing surface lands on the stator bearing surface due to the collapse of the air cushion, its rotational speed is less than that which would result in damage to the bearing surfaces.

Abstract: A motor drive having a very large dynamic speed range comprises a PID position feedback control system (8) in which the motor position is readjusted on the basis of the difference between the instantaneous (x.sub.a) and the nominal (x.sub.s) position. A series of nominal positions (x.sub.s) is determined from a nominal speed (v) in a speed control unit (5). The successive nominal positions (x.sub.s (t)) in a series exhibit a constant difference (.DELTA.x) relative to one another and are presented to the PID position feedback control system (8) with fixed intervals (.DELTA.t). A drive of this kind is used, for example in the beam collimator of an X-ray device.

Abstract: In a power system wherein a plurality of power plants, load systems and power transmission components are connected to each other for increasing the power transmission capacity of the power system, the power system is stabilized and power swings are suppressed, by controlling a semiconductor switch used in a power system stabilizing apparatus which is provided at the power system in an applying manner adequately corresponding to its operation characteristics and function, in accordance with a stabilizing command signal generated by using state values (for example, voltage, current, power, frequency, phase angle) of the power system, detected by detecting circuits provided in the power system.