Abstract: A control system is provided for an actuating member including a controller, a solenoid valve electrically coupled to the controller, a fluid driven actuator operatively coupled to the solenoid valve, an actuating member operatively coupled to the fluid driven actuator, a potentiometer operatively coupled to the actuating member for converting a rotational position of the actuating member into a proportional electrical resistance, signal converting means for converting the electrical resistance to a proportional electrical current, and means for conducting the current to the controller. The controller includes means for comparing the current to a control signal indicative of a desired position of the actuating member, and means for generating a voltage pulse to the solenoid valve to displace the fluid driven actuator and move the actuating member to the desired position. A method utilizing the above system is also provided.

Abstract: In a driving mechanism of a circuit breaker having first and second hydraulic operation apparatuses respectively driving a main contact and a resistor contact, a sequential control valve is provided between the first and second hydraulic operation apparatuses. The sequential control valve detects the operation of a differential piston for opening the main contact and switching the differential piston for sequentially opening the resistor contact after the opening of the main contact.

Abstract: A linear drive device has a linear motor which consists of a piston, an output rod and a control rod. The two rods extend through the two end plates of the motor housing. The working or output rod is designed for the transmission of power to some structure. The control rod cooperates a sensor for positioning. The sensor and also a valve arrangement is integrated in the housing end plate associated with the control rod. The valve arrangement controls flow through pressure fluid duct provided in the housing end plate at the control end for actuating the linear motor.

Abstract: The traverse apparatus of the subject invention is provided at the end of the main base 24 with a control box 38 having electromagnetic valves 57, 58, relief valves 59, 60, and manifold 61; and, one or more connectors 54 affixed at one end to sliding base 28 and at the other end to a separate sliding base 70. By these elements, the main body having cylinder 32 is separated from the rail guides 22, 23, the work of replacing a worn cylinder 32 is made easy, conveyance can be expedited, and the head mounting bases for attaching working heads can be increased readily.

Abstract: An apparatus and method are adapted for detecting an end-of-fill condition of an actuator having a varying control volume is provided. The end-of-fill condition corresponds to the varying control volume being pressurized to a predetermined end-of-fill pressure. The apparatus comprises a solenoid having a coil and an armature. The armature is movable relative to the coil in response to energization of the coil. A valve delivers a flow of fluid to the actuator. The fluid flow having a rate responsive to the movement of the armature. The apparatus and method controllably energizes the coil with a control current. The apparatus and method detects a flyback current in the coil, detects a change in the level of noise in said flyback current, and responsively producing an end-of-fill signal in response to the change being greater than a predetermined threshold.

Abstract: An implement control system is provided for controllably raising and lowering an implement relative to a work vehicle. The implement is pivotally connected to the work vehicle and movable between maximum raised and lowered positions in response to the extension and retraction of a hydraulic cylinder. The implement control system is operative for controllably connecting the hydraulic cylinder to a hydraulic accumulator as the implement reaches its desired position, thereby slowing movement of the implement in a smooth manner.

Abstract: An apparatus is adapted to detect the linear extension, velocity and acceleration of a hydraulic cylinder. The hydraulic cylinder defines a variable length coaxial resonant cavity Under the control of a controller, an RF transmitting section and an RF receiving section are used to determine the resonant frequency of the cavity. The receiving section includes a comparator circuit for increasing the sensor's sensitivity and eliminating spurious detections of the cylinder's resonant frequency. The linear extension of the cylinder is determined as a function of the resonant frequency.

Abstract: A hydraulic control system for controlling an actuator has a cylinder and a piston, and an oil pump. A first passage is communicated with the oil pump, and a second passage is communicated with the cylinder of the actuator. A plurality of branch passages are connected in parallel between the first and second passages, and a valve is provided in each branch passage. The hydraulic control system has a flow rate setting device for operating each valve thereby applying a predetermined quantity of oil to the cylinder of the actuator to shift the piston a desired distance.

Abstract: A method and apparatus for controlling the movement of an end point of an articulated arm in the x, y and z directions using a manually operated resolved motion control by controlling the component of velocity of the end point in each of the x, y and z directions to change by the same amount for a given change in the component of displacement of the manual controller in the respective x, y and z directions provided the total displacement in the selected x, y or z direction is less than a preselected displacement in the respective x, y or z direction and the end point is within a preselected work space.

Abstract: An apparatus for controllably actuating a hydraulic actuator is provided. The apparatus is connected between a source of pressurized hydraulic fluid and the hydraulic actuator. The apparatus controllably provides pressurized hydraulic fluid to the hydraulic actuator. The apparatus includes a controller for receiving an operating signal and a load pressure signal and responsively actuating the hydraulic actuator.

Abstract: An improved fluid controller (15) is provided having both rotary valving (47) actuated by the steering wheel (17), and axial valving (49) controlled by an electro-hydraulic valve (113) in response to a correction signal (31). In one embodiment, both the rotary valving and the axial valving are achieved by a primary valve member (63) and a follow-up valve member (65), and both the rotary and axial valving can be actuated simultaneously. Also disclosed is a logic control system for closed-loop control of the electro-hydraulic valve, whereby performance problems such as self-steering, wander, drift, and others are substantially eliminated.

Abstract: A method for checking the driving and control system of a hydraulic punch press is provided which comprises the steps of delivering a stop order signal to the driving device, sensing the position of the sliding punch member along its stroke and comparing the time or the distance required by the punch member to come practically to a stop, with preset reference values, and producing a fault signal when the time or distance exceeds the preset reference values.

Abstract: An electrohydraulic servovalve including a tailoring circuit coupled to provide a predetermined input signal to the motor of the valve. The predetermined signal functions to control the flow of fluid from the valve to effect a desired result. The electrohydraulic servovalve includes a housing defining round flow ports with a spool valve for metering flow through the ports. The spool valve substantially overlaps the round flow ports. The tailoring circuit includes a plurality of amplifiers each of which has a different gain. A command signal is applied to the amplifier and the output from the amplifiers is summed to provide an input signal to the motor of the electrohydraulic servovalve.

Abstract: A hydraulic drive is actuated by a CNC means via an electrically actuable valve. The pressure applied to the hydraulic drive or the force excerted by the hydraulic drive is supplied in the form of a signal to a pressure control means or a force control means. The output signal of the pressure- or force control means is supplied via a switch means--shortly prior to reaching the desired position value of the drive--to the electrically operated valve as a control signal. Simultaneously, the output signal of the switch means, which can be supplied to the valve, is interrupted, wherein the switching range shortly prior to reaching the desired position value is smaller than the admissible differential value, determined by the CNC means, i.e.

Abstract: A vacuum brake power booster with a connecting member (23) for the connecting nozzle (2) of the vacuum line and for the vacuum non-return valve (3). The connecting member is configured in the shape of a housing for a sensing device which detects the position of the diaphragm retainer (16) within the servo-cylinder (15). The sensing device consists of a scanning pin (22) which allows rotation of a gear (9) by means of a flexible toothed rack (6). The gear allows rotation of a tap (12) on an ohmic resistance. The different voltage values generated in this manner indicated the position of the diaphragm retainer within the servo-cylinder. By an appropriate selection of components, by their configuration, by their mutual adaptation, and by the appropriate assembly of these components into a compact overall assembly unit, the contour of a conventional vacuum brake power booster is not exceeded. The mounting space requirements of the booster are thus reduced. The booster is universally applicable.

Abstract: A hydraulically operated rotary drive includes a housing which is closed in hydraulically tight manner by flat covers and can be connected to a source of pressure fluid, a rotatable shaft extending through the covers out of the housing and a belt which is arranged at least in part within the housing with the formation of movable pressure chambers and is operatively connected to the shaft. In order to create a rotary drive which permits any desired extension to external structural groups as well as a modular extension to a plurality of rotary drives, it is proposed that axially extending channels (2, 2') for receiving and forwarding the pressure fluid to the pressure chambers and electrical connections be integrated within the shaft and that the shaft (3) be provided on both axial ends with coupling elements for the coupling outside the housing of mechanical and/or electrical attachment modules which can be coupled to the rotary movement.

Abstract: An apparatus, is adapted to controllably position a movable element in a hydraulic motor. A controller receives a request signal and velocity and/or position signals from sensors. The controller, in accordance with a control scheme using velocity and/or position feedback, determines the flow of hydraulic fluid to the cylinder needed to reduce velocity and/or position errors. A directional valve, actuated by an electrohydraulic pilot system, delivers hydraulic fluid to the hydraulic motor.

Abstract: In a device for carrying out quality test firings with a gun barrel (1), a mount (2) and an automatic adjusting arrangement (4, 5, 6) for resetting the barrel (1), a given directional setpoint value is compared with the actual direction value. While the actual value is derived from a mirror (3) attached to the barrel (1) itself, the setpoint value is produced by a frequency-modulated laser beam (.nu.) from a source mounted nonvibratingly and separately from the barrel (1) and its mounting (2). By this separation, the hit dispersion due to the mechanical components is reduced to a minimum. This device is of particular usefulness in the development and quality control of small-calibre ammunition.

Abstract: This actuating drive (1) has a main piston (4) which can be operated by means of an oil pressure and a pilot control system in effective connection to the main piston (4) by means of a linkage (15). The pilot control system includes a control orifice (14) controlling the oil pressure at the main piston (4) and a pilot control piston arrangement (18) which can be operated hydraulically.The actuating drive (1) is to be designed in such a way that it has improved dynamic characteristics during operation. This is achieved by the fact that the pilot control piston arrangement (18) can be operated by means of an electrohydraulic valve which is triggered by an electronic control unit (31).

Abstract: Vehicles having implements are typically used to perform repetitive functions in work cycles. An implement control system raises and lowers an implement relative to the vehicle and reduces the stresses applied to the vehicle from abruptly stopping the motion of the implement. A lever pilot signal is produced in response to the pivotal position of a control lever. An electrohydraulic pilot signal is also produced. The pilot signal having the greater pressure is directed to a main valve for controlling the position of the implement. The method and apparatus of the instant invention are applicable to a number of vehicles having a hydraulically operated implement.

Abstract: A positioner for use in pneumatic systems moves a pneumatic operator. The positioner is an electronic pilot positioner or electronic to pneumatic interface which provides accurate positioning of linear actuators in response to an electronic control signal. The actuator is moved as pneumatic fluid is exhausted or supplied through the exhaust valve and supply valve. The positioner utilizes two solenoids for controlling a supply valve and an exhaust valve. The positioner includes a control circuit which receives a signal from a central controller and a signal from a feedback circuit. The control circuit compares the feedback signal and the controller signal and generates a signal for positioning the actuator.

Abstract: A loading/unloading control apparatus for a industrial vehicle control the discharge capacity of a variable displacement type hydraulic pump in accordance with the detected result of the amount of load applied to a loading/unloading hydraulic actuator or with a manual setting by an operator, thereby to obtain the most suitable working speed of the actuator for loading/unloading operations.

Abstract: A double acting hydraulic cylinder is a die cushion for a press, with an upper and a lower chamber in communication with each other and with a differential pressure between the two chambers automatically controlled by a valve mechanism. With the differential pressure controlled according to one of several desired curves, the die cushion capability during press operation can be changed and adjusted to a valve suitable for the product to be processed and so a wide variety of products can be produced in high quality and high efficiency.

Abstract: An actuator for a control valve with a control circuit has a main piston which slides in a main cylinder. On one side of the main piston, there is arranged a drive volume, which can be pressurized with oil in a controlled manner, on the other side of which there is arranged an oil-filled buffer volume. The actuator despite having a greater capacity, has a comparatively high dynamic performance which has positive effects particularly when closing the control valve. This is achieved in that the drive volume and the buffer volume can be connected through a connecting line which can be sealed off by a valve. This valve is activated directly hydraulically via a second valve.

Abstract: A rotary hydraulic machine which includes a housing having a shaft mounted for rotation within the housing about a shaft axis. A cylinder block is coupled to the shaft for co-rotation with the shaft within the housing and includes a plurality of cylinders disposed in a circumferential array parallel to and surrounding the shaft axis. A piston is disposed to reciprocate within each of the cylinders and is coupled to a yoke for determining displacement of the pistons within the cylinders. A valve plate is mounted on a valve block and includes kidney-shaped slots for registering with the cylinders as the cylinder block rotates, and thereby connecting the cylinders to pump input and output ports. A microprocessor-based controller is externally mounted on the pump valve block and includes internal memory having various remotely-selectable control programs prestored therein.

Abstract: A dual servo actuation system is automatically equalized or rigged by electronic control circuits. A static auto rigging bias is applied to one or the other, or both, of a pair of electro hydraulic servo valves that respectively control two hydraulic actuators driving a common member, such as an aircraft control surface. An auto rigging bias, which substantially eliminates force fight, is automatically generated and stored as a fixed quantity prior to use of the system for control of the common member. With a zero commanded output of the two actuators, a difference of differential pressures at the actuators is obtained and caused to change the number in a counter as long as the difference exceeds a threshold. The counter number, while it is above the threshold, is continuously applied as a bias signal to decrease the force fight, and the number in the counter is stored as a fixed bias signal when the force fight indicated by the difference of differential pressures drops below the threshold.

Abstract: An electro-hydraulic servo mechanism comprising: a hydraulic actuator formed with a pair of hydraulic chambers and having an output member which is displaced by a differential pressure between the hydraulic chambers, the output member being connected with an object to be controlled; an electro-hydraulic converter for varying the differential pressure between the hydraulic chambers in response to an electric signal; a first differential transformer for outputting a first induced electromotive force proportional to the displacement of the output member; a control circuit for generating the electric signal in response to the output of the first differential transformer and to an external command signal and for outputting the electric signal to the electro-hydraulic converter; a pressure receiving member that is displaced in response to the differential pressure between the hydraulic chambers; and a second differential transformer for outputting a second induced electromotive force proportional to the displacemen

Abstract: There is disclosed a method of controlling a hydraulic actuator by using a normally closed solenoid valve and two normally open solenoid valves and selectively actuating them to place the piston of a hydraulic cylinder in position. The normally closed valve is installed in the fluid passage connecting a hydraulic pressure generator with the hydraulic cylinder and on the side of the generator. The normally open valves are connected in series downstream of the normally closed valve. At the beginning of the operation of the cylinder, the normally closed valve is opened after a lapse of a waiting time long enough for that of the normally open valves which corresponds to the direction of movement of the piston to be closed completely. At the end of the operation of the cylinder, the normally open valves are opened after a lapse of another waiting time long enough for the normally closed valve to be closed completely.

Abstract: A pneumatically driven hydrostatic actuator and a pneumatically driven recirculating hydraulic actuator are provided. Each of these actuators consists of a hydraulic pump fluidly coupled to an actuator. The pump is driven by a low inertia pneumatic motor that extracts pressure energy from pressurized gas and converts it to rotary motion. The pneumatic motor is preferably made from stainless steel A286 so that it can operate using pressurized hydrogen gas. The components of both actuators are in a closely coupled relationship so that they can be arranged in a compact unitary package.

Abstract: An apparatus for controlling operating reaction of winch comprising a reaction device whose output is variable for applying the output as an operating reaction to an operating lever of a winch, load detection means for detecting a lifting load of the winch, lever operating amount detection means for detecting an operating amount of said operating lever, and a controller for indicating an output having a value corresponding to the lifting load and the lever operating amount to said reaction device on the basis of the detection amount by said load detection means and said lever operating amount detection means.

Abstract: A hydraulic control system is provided for regulating the slew rate of a servovalve driven actuator within design parameters despite widely varying load conditions. The servovale flow is maintained constant in accord with the integration of the difference between a set slew rate command signal and a measured slew rate feedback signal. Where a plurality of such actuators are driven from a single hydraulic pump, this regulation of servovalve flow also enables the pump supply pressure to remain constant despite widely varying load conditions on the individual actuators in the system.

Abstract: A drive for a steam servo valve (2), including a control valve arrangement for regulating the actuating pressure of a servo drive (1), whereby the drive can always be actuated reliably and quickly even with comparatively high oil pressure. This is achieved by the control valve arrangement having at least two regulatable control valves (17, 21) which are pressure-actuated via at least one pilot regulating valve (proportional pressure valve 29, 34).

Abstract: A multiplexed hydraulic control system which avoids the use of a rotary multiplexer and thereby allows for random selection of the multiplexed outlet ports and variable dwell times for the respective ports. A single hydraulic input is multiplexed among a plurality of hydraulic outputs. A control system provides two types of signals: (1) modulation signals selected from a plurality of multiplexed input signals for producing a modulating hydraulic flow, and (2) selector signals for operating on the multiplexer means to route the modulated signal to the appropriately selected channel.

Abstract: A linear unit (10) is provided with a cylinder (50) and a pressure-fluid actuated piston (52). The piston (52) runs in a borehole (51) of the cylinder (50). A slider (55) runs at the cylinder (50). A band (53) connects the piston (52) to the slider (55) and leads via deflection structure (54a, 54b) at the heads (11a, 11b) of the cylinder (50). Valves (15a, 15b) are screwed into the cylinder heads (11a, 11b) for feeding a pressure fluid to and discharging a pressure fluid from the borehole on two sides of the piston (52). The linear unit (10) provides an increased liberty of direction in a position-mounting of the linear cylinder heads (11a, 11b) and of the linear unit with valves (15a, 15b) as well as in the positioning of the connection terminal pieces. The linear unit (10) is flexible and is of modular construction and allows different types of device components to be flanged in the same position.

Abstract: The reproducing system 9, 10, 42, 43 controls rotation of the rotor 30 of the electric motor 28 in order to provoke a variation in the leakage of the leakage relay 33 with a view to varying the position of the piston 2 of the jack 1. The stator 34 of the motor 28 is connected by a mechanical link 36 to the piston rod 2a of the jack 1. In the event of no-voltage, the brake 29 of the motor acts in order to connect the rotor 30 and the stator 34. The position of the rod 2a may then be varied by mechanically rotating the rotor-stator assembly 30-34 by a crank 41.

Abstract: A multiplexed hydraulic control system having a plurality of hydraulic channels for individually controlling the positions of a plurality of actuators in the respective channels in accordance with a corresponding plurality of electrical control signals. The system includes a relatively small multiplexing valve or valve array which has a common input and a plurality of individually selected outputs. The multiplexing valve has a control input which is responsive to a source of binary selector signals, such selector signals being used to directly address any particular channel connected to the multiplexer. The system also includes means for modulating a hydraulic signal in accordance with selected ones of the plurality of electrical control signals, and applying the modulated hydraulic signal to the multiplexer common input.

Abstract: An electrohydraulic system for bending tube stock includes a bend head having a mandrel and an actuator coupled to a bending die for engaging the tube stock and bending the stock around the mandrel. A clamp is coupled to a second actuator for gripping the tube stock, and a third actuator mechanism in the form of a boost cylinder is coupled to the clamp for urging the tube stock lengthwise into the bend head. An electrohydraulic valve is responsive to an electronic valve control signal for variably feeding hydraulic fluid to the boost cylinder, and velocity of slip at the clamp is determined. An input pressure command signal is compared with pressure at the boost cylinder to develop a pressure error signal. Slip velocity is compared with a velocity limit command to develop a velocity difference when slip velocity exceeds the velocity limit, and the pressure error signal is modulated and employed as the valve command signal to maintain slip velocity at or below the level of the velocity limit command.

Abstract: A stability compensating circuit of a servomechanism wherein the output displacement of an actuator is controlled, comprising: a unit generating a reference input signal corresponding to a target value; a first adder which is provided in a first line between the reference input signal generating unit and the actuator and to which a feedback signal from the actuator is inputted through a second line between the first adder and the actuator; a second adder provided in the first line between the first adder and the actuator; a first compensating circuit provided in the first line between the first and second adders; and a second compensating circuit provided in a third line between the second adder and the actuator, the feedback signal from the actuator being inputted to the second adder through the second compensating circuit.

Abstract: A rotary hydraulic machine which includes a housing having a shaft mounted for rotation within the housing about a shaft axis. A cylidner block is coupled to the shaft for co-rotation with the shaft within the housing and includes a plurality of cylinders disposed in a circumferential array parallel to and surrounding the shaft axis. A piston is disposed to reciprocate within each of the cylinders and is coupled to a yoke for determining displacement of the pistons within the cylinders. A valve plate is mounted on a valve block and includes kidney-shaped slots for registering with the cylinders as the cylinder block rotates, and thereby connecting the cylinders to pump input and output ports. A microprocessor-based controller is externally mounted on the pump valve block and includes internal memory having various remotely-selectable control programs prestored therein.

Abstract: A linear drive mechanism has a combination of a drive cylinder, a drive rod stroke-limiting element, position sensors, a solenoid, and a terminal strip, together with internal wirings and hose connections. The drive mechanism can be arbitrarily arranged quickly and simply at a processing apparatus or assembly structure as a unit, and only a cable having the external signal and control lines as well as a supply line for the pressure agent need be connected thereto. No disturbing and involved wirings and position sensing elements therefore need be arranged in the actual tool region.

Abstract: An articulated arm employs a controller to generate .delta.r, .delta..THETA. and .delta.z signals for controlling the movement of the arm in r, .THETA. and z directions to product movement of an end point from an initial location along a desired path toward a desired location. The actual location is determined by sensing the relationships between the arm segments and determining the actual location of the end point. The actual location is continuously compared with the desired location represented by the r, .THETA. and z signals and, if the difference between the actual location and desired location exceeds preselected limits, the .delta.r, .delta..THETA. and .delta.z are scaled down thereby redefining the desired location to ensure that the actual arm movement does not lag an unacceptable amount relative to the desired location.

Abstract: An apparatus is adapted to detect an end-of-fill condition of an actuator having a varying control volume, C. The apparatus includes a solenoid having a coil and an armature. The armature is movable relative to the coil in response to energization of the coil. A control valve delivers a flow of fluid to the actuator. The rate of the fluid flow is responsive to the movement of the armature. An electrical circuit detects a voltage spike across the coil and responsively produces an end-of-fill signal. The voltage spike is generated by an electromotive force produced by the armature in response to the control volume achieving a predetermined end-of-fill pressure.

Abstract: A multiplexed hydraulic control system having a plurality of channels and a common source of modulated hydraulic fluid. The common source is shared among the plurality of channels by providing a plurality of selector valves, one for each channel, with electrical solenoids for the selector valves being individually controlled by a control means. In a normal operating mode, the selector valves are operated individually and the modulating means is controlled to direct fluid to the selected channel in accordance with the demands placed on movement of the actuator in that channel. In a second slewing mode, multiple selector valves are energized at the same time and the modulator is controlled to produce sufficient fluid flow to slew all of the actuators in the selected channels at a desired rate.

Abstract: A multiplexed hydraulic control system in which high force margins for the multiplexer are achieved by employing hydraulic oscillators as the multiplexer driving means. The multiplexer is typically in the form of a hydraulic cylinder having an input port and a plurality of output ports, with an operator in the cylinder for individually connecting the input port to the output ports. The hydraulic oscillator is mechanically coupled to the multiplexer operator, and oscillation of the former causes oscillation of the latter to sequentially connect the input to each of the outputs. Various means are taught for initiating reversal of the oscillator and controlling the oscillation speed.

Abstract: An operating force controlling device includes a pair of reactive force mechanisms (70, 70') disposed in an opposing relationship to each other in the direction of operation of an operating lever (60). A load pressure of a motor (30) is detected by a detector (91, 91'), and a controlling signal is outputted from a controller (90) in response to the load pressure. A pilot pressure is outputted from an electromagnetic proportional pressure reducing valve (80) in response to the control signal. The pilot pressure is inputted into one of the chambers of the reactive force mechanisms (70, 70') which moves a rod (72, 72') to project, to apply an operation reactive force to the lever (60). The operation reactive force is controlled such that the rate of change thereof may be high when the load pressure of the motor (30) is low but may be low when the load pressure is high.

Abstract: A remote control shifting system for a mechanical transmission. The transmission is operated by two pneumatic cylinders, a selecting cylinder operating in the direction of shift path selection and a shifting cylinder acting in the direction of shifting. The shifting cylinder operates with two force stages, a lower force for effecting synchronization of gears about to be engaged, and a higher force level for actually engaging or disengaging the selected gears. A remote shift control unit is designed to closely emulate the action of a direct-operating manual shift level. During the synchronizing phase, the shift lever moves easily in the shifting direction. After a preliminary movement, however, further movement is allowed only against considerable resistance, as if conventionally mechanically forcing gears into meshing engagement.

Abstract: Either a reciprocating or a stationary part in each of juxtaposed cylinder devices is provided with a scale having alternate projections and depressions which are arranged with regular pitches in a direction of reciprocation of the reciprocating part, while the other part is provided with a sensor engaging the scale for determining whether it is a projection or depression of the scale that the sensor engages at a particular point of time, and producing a pulse whenever it falls in any of the depressions. According to one preferred embodiment, the projections and the depessions of the scale of one of the cylinder devices are staggered relative to those of the scale of the other cylinder device by half a pitch. Thus, when the two cylinder devices are in synchronous operation, the sensors of the cylinder devices produce alternate pulses which do not overlap with each other in the time of occurrence.

Abstract: A control system for controlling a double-acting cylinder includes four pilot-operated, proportional-type poppet valves for controlling fluid flow between the cylinder, a pump and a reservoir. Four solenoid-controlled pilot valves operate the poppet valves in response to error signals generated by a control circuit. The control circuit receives a cylinder position feedback signal and an operator-generated command signal. The control circuit provides for float, shutdown, variable deadband and pressure adjustment operation.

Abstract: An apparatus is provided for controllably positioning a movable element within a hydraulic motor in response to a flow request signal. An electric circuit receives the flow request signal and responsively produces an energization signal. An electromagnetic actuator has a core, and a coil with a plurality of windings wound as a helix around the core. The coil is adapted to receive the energization signal and responsively produce a magnetic force proportional to the magnitude of the energization signal forcing the core to move bidirectionally relative to the coil. A mechanical coupling has one end connected to and movable with the core. A directional valve includes a spool connected to the other end of the mechanical coupling. The directional valve precisely meters pressurized fluid to the motor causing the movable element to move in response to the movement of the core.

Abstract: An electro-rheological fluid damped actuator having an actuator housing w a moveable element such as a piston and rod assembly disposed within the housing. The actuator further comprises a hydraulic circuit with an electro-rheological fluid disposed in the hydraulic circuit. The hydraulic circuit and rheological fluid provides an active and variable damping force on the moveable element. The damping force is controlled by the output of an electrical circuit which creates an electric field within the hydraulic circuit. The electric field will cause the viscosity of the electro-rheological fluid which is exposed to the electric field to increase or decrease in accordance with the magnitude of the electric field. The increase in viscosity of the electro-rheological fluid as it flows through the actuator provides an active damping force on the actuator which allows a more precise control of the output motions of the actuator.