Abstract: A multistage control method of a flow rate control valve which is opened or closed when a DC motor rotates. The method includes dividing angular speed limit areas of the DC motor depending on stages based on limit values so that angular speed values of the DC motor are to be scheduled depending on the stages and controlling the DC motor to rotate at a determined angular speed value depending on a corresponding angular speed instruction to the DC motor within one angular speed limit area. When the angular speed value of the DC motor is outside a limit value of the corresponding angular speed limit area, the DC motor rotates at a determined angular speed value until reaching outside a limit value of the corresponding limit area depending on a corresponding angular speed instruction to the DC motor within an angular speed limit area of the next stage.

Abstract: A pneumatic shifting force supporting device for a gearbox comprises a housing structure having a compressed air inlet and an air vent, and a control rod and an output unit comprising a working piston defining two pneumatic working chambers. A valve arrangement is functionally provided between control rod and output unit. By acting on the two pneumatic working chambers, the valve arrangement causes a pneumatic follow-up control from the output unit to the control rod comprising two valve pistons, annular sealing edges, valve spools and valve seats. A throttle slide is associated with at least one of the valve pistons and is slidable relative thereto. The throttle slide has a closing edge co-operating with the respective associated valve seat and delimiting at least one throttle passage, the cross-sectional area of which depends on the relative position of the throttle slide with respect to the associated valve piston.

Abstract: Apparatus and methods for eliminating back drive in a push pull type control system, are provided. An exemplary apparatus includes a control rod including a pair of spaced apart piston displacement members each configured to carry a check valve. The apparatus also includes a pair of opposite-face check valves each configured to seal against respective opposing face of a piston head to form a hydraulic lock, preventing back drive in the control system.

Abstract: Provided an electrically-operated hydraulic actuator unit that includes an electrically-operated motor controlled by a control apparatus and actuating a volume adjusting mechanism through driving-side and driven-side arms, and a clutch mechanism in which the driven-side arm presses a contact member against a clutch case so that the driven-side arm is locked when a force from the volume adjusting mechanism is applied to the driven-side arm. The control apparatus can set duties of first to fourth drive signals to be output to the electrically-operated motor in a neutral-side start period, a neutral-side ordinary actuation period, a higher-volume-side start period and a higher-volume-side ordinary actuation period. The duties of the first and fourth drive signals are larger than that of the second drive signal, the duty of the third drive signal is larger than that of the fourth drive signal, and an integrated ON-time of the third drive signal is larger than that of the first drive signal.

Abstract: A fluid distributor apparatus includes a body having distribution ports; a spool adapted for controlling the distribution ports and mounted slidingly in a first sliding seat obtained in the body and communicating with the distribution ports; a copying-member mounted slidingly and sealed in a second seat obtained in the spool; and a supply system for a controlled supply of the fluid to the second seat, so that the copying-member slides in a controlled way. The supply system includes also a chamber containing the fluid and communicating with said the seat, and a pushing device of the fluid mounted slidingly and sealed in the chamber.

Abstract: A method that provides increased flexibility to measure dynamic range of a rotating system is provided. The method includes the steps of: providing a first rotating member; providing a second rotating member suitably engaged to the first rotating member; providing a set of sensors disposed to sense variations in characteristics along a circumference of the first member and the second member respectively; providing a controller for receiving information sensed by the sensors; determining a rate of rotation of the rotating members; selectively using the sensed information thereby at different rate of rotation different amount of the sensed information is used.

Abstract: The invention relates to a hydraulic control apparatus for a construction machine. The hydraulic control apparatus includes a target velocity table (4) which stores target actuation velocities of a hydraulic actuator (30) corresponding to operation amounts of the operation member (2) to be operated by the operator, a target acceleration table (5) which stores target actuation accelerations of the hydraulic actuator (30) corresponding to operation amounts of the operation member (2), and one of the target velocity table (4) and the target acceleration table (5) can be selected by operation of a selection switch (3) by the operator. Further, by the control means, the target value corresponding to the operation amount of the operation member (2) using the table selected by the selection switch (3), and a control valve (17) for controlling the pressure oil supplying amount from a hydraulic pump (16) to the hydraulic actuator (30) is controlled based on the set target value.

Abstract: A control system for operating a hydraulic system includes a user input device which generates an input signal indicating desired movement of a hydraulic actuator. A mapping routine converts the input signal into a velocity command indicating desired actuator velocity. A valve opening routine transforms the velocity command into a flow coefficient which characterizes fluid flow through the valve assembly and from the flow coefficient produces a set of control signals designating levels of electric current to apply to valves within the valve assembly. A pressure controller regulates pressure in the supply line in response to the velocity command. When the hydraulic system has a plurality of functions, the control system adjusts each velocity command to equitably apportion fluid to each function when the aggregate flow being demanded by the functions exceeds the total flow available from a source.

Abstract: A method for controlling a fluid system is provided. The system may include a hydraulic circuit having a pump driven by an engine, wherein the pump delivers fluid to an actuator through a valve assembly. The method may include receiving an operator input and determining a condition of the hydraulic circuit. The condition of the hydraulic circuit may include at least one of a flow rate of fluid to the actuator, an engine speed, and a pump displacement. The method may include determining a valve transform function as a function of a position of a linkage associated with the actuator and the condition of the hydraulic circuit. The method may further include determining a valve command in response to the valve transform function and the operator input, wherein the valve command results in a consistent deadband. The valve command is delivered to the valve assembly.

Abstract: An improved control system for die casting or similar machines wherein a closed loop velocity feedback circuit is supplemented with an integration circuit and two filtering circuits to compensate for the frequency response of the pilot valve in the die casting machine. The integration circuit serves to more accurately cause the velocity of an element being controlled to match the desired/commanded velocity, and also caused the velocity to more rapidly match the desired/commanded velocity.

Abstract: A servo operation apparatus for a transmission comprising an input shaft to which the shift-change operation force is mechanically transmitted from a shift lever, a servo unit for boosting the shift-change operation force by feeding a working fluid, and a valve device which feeds the working fluid to, or drains the working fluid from, the servo unit depending upon the shift-change operation of the shift lever, wherein provision is made of an working fluid feed control means which feeds the working fluid in such a manner that the pressure of the working fluid in the servo unit is raised with a steep gradient in the former half until a predetermined initially raised pressure value is reached and, thereafter, is raised in the latter half with a gradient less steep than that of said former half.

Abstract: A positioning system uses a position feedback signal to position and damp a platform. The position feedback signal is input to an electronic controller that provides a plurality of control signal that are used to position the platform and dampen the platform motion.

Abstract: An electrohydraulic governing system for governing system for governing at least movements of objects (3, 4) actuated by pressure fluid, one at the time or several simultaneously, which can receive or deliver energy, wherein the governing desires from an impulse generating guide means (1) via an electronic guide unit (2) are performed provided that this is possible in view of limitations in a pressure fluid source (5) delivering pressure fluid to the objects or provided this can be allowed in view of the strength, life and stability of the machine governed by the guide system or by the objects and as long as the functions operate and as long as the guide system or the guided machine is governed within limited secure field, wherein all the time the volume of the different parts or the sytem filled with pressure medium is measured directly or indirectly and upon governing of the pressure medium source and the valve means (8, 13, 15) connected to respective object it is governed so that the pressure fluid source

Abstract: A closed loop control system for a pneumatic actuator using position and pressure feedback signals. The feedback signals are supplied to a microprocessor which successively generates a desired acceleration, a desired actuator force, a desired gas pressure, and a gas mass flow rate command for a gas flow controlling valve. The use of the gas flow rate as a control variable decouples pneumatic ronlinearities from the control loop. Nonlinear viscous friction, coulomb friction and load effects are decoupled from the control loop prior to the calculation of the desired pressure. An improved trajectory is achieved by employing a plurality of trajectory phases, including a velocity control phase.

Abstract: A weapon stabilization system for an unbalanced gun tube pivotally mounted on a tank turret or other movable platform is disclosed. The system includes a muzzle position controller which accounts for flexion of the gun tube and which comprises a muzzle reference sensor and a muzzle deflection feedback circuit. The muzzle reference sensor provides a signal indicative of deflections of the gun tube. The muzzle deflection feedback circuit is responsive to this signal to adjust the position of the gun tube in a manner that accounts for the deflections of the gun tube. The gun tube is positioned using a hydraulic actuator with pressure feedback to the stabilization system. The system includes a feedforward controller to compensate for the positive pressure feedback due to dynamic external accelerations acting on the unbalanced gun tube.

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: A control system, having an input command signal and driving a prime mover, is provided with variable magnitude and/or rate input signal limiting that is adjusted by maps 68,70,72,74 which set the limits for a variable magnitude limiter 14 and a variable rate limiter 22 as a function of the prime mover rate. The limiting is adjusted dynamically as the prime mover rate changes. When the prime mover enters an undesirable operating condition, the maps only limit the command signal in the direction of such condition. The adjustable limiting is enabled or disabled based on the position, rate, and/or acceleration of the prime mover.

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 system for the control of a fluid flow control valve which controls the supply of fluid to an actuator to control the movement of a component such as a tractor implement hitch in response to a selected operating parameter such as hitch position or draft force. The system enables the desired value of the selected parameter to be set and this desired value is compared with the actual sensed value of the parameter to provide a parameter error signal. A start-up control function is provided to improve the initial speed of response of the system. The start-up control function is arranged on each detection of a parameter error signal to apply a start-up signal to the valve to initiate movement of the component and, if no movement results, to increase the start-up signal until movement of the component is detected whereupon the increase in the start-up signal is stopped and the magnitude of the signal applied to the valve is dependent on the parameter error signal so as to tend to reduce the error signal to zero.

Abstract: A hydrostatic drive assembly with an adjustable pump driven by a primary power source, which acts on several consumers of hydrostatic energy, is disclosed which has a control and regulating device with nominal speed value pickups and adjustable restrictors for each consumer. In order to obtain a control and regulating device at a low production cost, one that operates with a low power loss, it is proposed that the nominal speed value pickup send an electric signal to an electronic control device, that each consumer be provided with an actual speed value pickup, which the control device, and the restrictors assigned to each of the consumers in their connection lines are designed as electromagnetic throttle valves controlled by the electronic control device.

Abstract: Apparatus and method for dispensing fluid materials wherein the fluid is discharged from a nozzle at a rate controlled by a metering valve having a seat and a stem moveable with respect to the seat to modulate the flow. A servo-actuator connected in a feedback control loop is used to position the valve stem with respect to its seat in accordance with a control signal. The control signal is derived in accordance with the difference between a driving signal representing a desired flow rate and the sum of a pair of feedback signals. One feedback signal represents the actual flow rate while the other feedback signal is correlated to both the relative velocity and position of the stem with respect to the seat. The position-dependent velocity signal is generated by a transducer comprising a magnet and a coil influencable by the field of the magnet as the magnet and coil move relative one another.

Abstract: In a dynamic characteristic compensating device for an electrical hydraulic servo actuator, a differential pressure detecting piston is displaced in proportion to the difference in pressure between two hydraulic operating chambers provided on opposite sides of the main piston in the actuator, and a speed detector converts the displacement of the differential pressure detecting piston into an electrical signal. The electrical signal is fed back to the control signal input circuit side of an electrical hydraulic servo valve, to control the valve in such a manner that differential pressure variations due to disturbances applied to the actuator are canceled out by the feedback signal.

Abstract: A spindle carrier, which is movable vertically by an electric servo motor through a relatively long ball screw, has a substantially constant counterbalance force maintained on it irrespective of whether it is moving up or down. This prevents compression or tension of the ball screw. The counterbalance force is maintained substantially constant through sensing the load on the spindle carrier and using the sensed load to vary the hydraulic pressure applied to a piston within a hydraulic cylinder and connected through a chain to the spindle carrier to apply the counterbalance force.

Abstract: Method and apparatus of controlling and positioning a fluid actuator by supplying pressurized fluid to right and left actuating chambers of the actuator through an on-off control valves. To drive and position the actuator rapidly and accurately, the actuator can be driven at a higher speed by an initial driving force until it reaches near the desired position and continuously moved at a low speed by gradually increasing the fluid pressure to be supplied to the right and left actuating chambers of the actuator. The initial driving force in the high-speed range becomes maximum when the pressure is applied to one of the right and left actuating chambers while at the same time the other actuating chamber is exhausted. In the low-speed range and near the target position, the one actuating chamber is continuously supplied with the pressure while at the same time the other actuating chamber is gradually closed.

Abstract: A control system (10) for supplying an operational chamber (38) in an air motor with pressurized fluid causing rotors (18 and 20) therein to move and develop an output torque in response to an input signal. Electrically operated valves (52 and 54) selectively controlling the flow of fluid from first and second bellows means (48 and 50) which are normally seated to seal distribution conduit (34 and 36) connecting the operational chamber (38) to the atmosphere. A select high disc valve (104) in the fluid pressure supply passage provides operating fluid to the distribution conduit (34 or 36) opposite the one which is vented to the atmosphere. In a two position air motor powered actuator, the electrical signals for the valves (52 and 54) may be derived as a simple function of actual rotor rotation and rotor rotational speed.

Abstract: A servo system for a braked accelerative transport in which a signal representing velocity of a carriage within the transport is compared to a first reference signal representing desired carriage velocity. The comparison yields an error signal which is used to adjust the brake of the transport. A hydraulic valve having an adjustable needle is used as the brake. A second selectable reference signal is provided so that the first reference signal can be bypassed when the carriage is reset at high velocity or is at reset. The valve is also bypassed on reset so that the adjusted brake mechanism is left intact on reset.

Abstract: A power stage servo valve for a seismic vibrator includes a stationary orifice plate defining a plurality of valve ports having a first shape. A rotary orifice plate, abutting the stationary orifice plate, defines a like plurality of valve ports that have a shape different from the valve ports in the stationary orifice plate. The configuration and shape of the rotary valve ports is such that the valve opens more quickly than it shuts off when the plate is rotating continuously in one direction at a desired angular velocity.

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: To reduce the piston velocity in a cylinder as the piston approaches the end positions, a signal transmitter is provided for sensing the position of a part driven by means of the piston and cylinder assembly, and thus of the piston in the cylinder. The signal of the signal transmitter is applied to a control unit in which it is compared with a signal from an actuator means. The signal from the actuator means controls the extension and shortening of the piston and cylinder assembly and the velocity at which this occurs, and may be positive or negative. The comparison of signals is so exploited that if it is established by this comparison that the piston is not in the areas of the end positions or, alternatively is in these areas but is activated by the actuator means to move away therefrom, the signal from the actuator means is not acted upon, whereas if the piston is in these areas and approaches the end positions, the hydraulic fluid supply to the piston and cylinder assembly is continuously reduced.

Abstract: A torque control for a fluid operated motor includes a first gear to be driven through operation of the motor and a second gear in driving engagement with said motor and maintained in a generally stationary position during normal operation thereof. The torque control further includes a drive mechanism connected to the first gear and to a load to be rotationally driven through operation of the motor. A valve is provided in the fluid supply to the motor to open and close the supply of fluid thereto. Disconnect means is operatively connected to the second gear and the valve to maintain said valve in an open position to permit supply of fluid to said motor when the second gear is stationary. The second gear rotates when the torque required from the motor to rotate the load exceeds a predetermined magnitude to move the disconnect means relative to the valve to close the valve to terminate the supply of fluid to the motor.

Abstract: This invention relates to a chain conveyor wherein the tension of the chain or chains thereof is controlled by a closed-loop servo system. The servo-system includes an electrically-operable servo-device. An electrical signal dependent on the torque of an electric motor driving the conveyor is applied to the servo-device for operation thereof to control a piston-and-cylinder device which is adapted to alter the distance between a chain-driving sprocket and another sprocket of the conveyor. The arrangement controls the tension of the or each chain at the point where the chain is just leaving the circumference of the first-mentioned sprocket, maintaining the tension at a constant value which may be near to zero under all conditions of operation.

Abstract: A fluidic system for stabilizing movement of a body subject to oscillation at its natural frequency, such as a tank-mounted gun, with appropriate circuitry and controls for notch filtering control output signals at the natural frequency.

Abstract: Two embodiments of closed loop electro-fluidic controlled systems are disclosed for controlling the velocity, acceleration, torque, force of pressure applied to a member. The system includes a source of electrical command signals correlated to the desired magnitude of the parameter being controlled, a transducer responsive to the controlled member for providing an electrical feedback signal correlated to the actual value of the parameter, and a circuit for providing an error signal correlated in magnitude and polarity to the magnitude and sense of the difference between the actual and desired values of the controlled parameter. Also included is a transducer responsive to the error signal for applying a positioning force to a movable valve closure element, which is subjected to no other forces, to regulate the application of pressurized fluid through the valve to the controlled member in dependence upon the error signal.

Abstract: Disclosed is a hydraulic servomechanism including a control loop consisting of an input device, an adder-amplifier, a servovalve, a cylinder or actuator and a load operatively connected in the order named for controlling the position of the load, a position feedback loop and an acceleration feedback loop. In one embodiment of the invention, the hydraulic servomechanism further includes a feedback loop wherein an output from an accelerometer or pressure sensor for detecting a differential pressure across a piston in the cylinder and an error signal from the adder-amplifier are arithmetically processed and fed back to the adder-amplifier.

Abstract: A combined feedback control system for a servo actuator including a ram that produces a mechanical displacement output of the system as directed by a position command signal. In the combined feedback control system a lever arrangement mechanically combines displacement and velocity information of the ram, and such combined information is conveniently transduced and electrically combined with the position command signal to develop an error signal that controls an electro-hydraulic valve. The latter preferably through a fluid amplification stage controls the delivery of fluid to the ram and, thus, the position thereof. Through the lever arrangement a mechanical failure control is operative to move the ram to a predetermined position upon failure of the electro-hydraulic valve and a manual control is operable to control the ram position via the fluid amplification stage.

Abstract: Two embodiments of closed loop electro-fluidic controlled systems are disclosed for controlling the velocity, acceleration, torque, force or pressure applied to the member. The system includes a source of electrical command signals correlated to the desired magnitude of the parameter being controlled, a transducer responsive to the controlled member for providing an electrical feedback signal correlated to the actual value of the parameter, and a circuit for providing an error signal correlated in magnitude and polarity to the magnitude and sense of the difference between the actual and desired values of the controlled parameter. Also included is a transducer responsive to the error signal for applying a positioning force to a movable valve closure element, which is subjected to no other forces, to regulate the application of pressurized fluid through the valve to the controlled member in dependence upon the error signal.

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.