Abstract: The invention is an apparatus for physically exchanging a force with a user in an environment local to the user. A connection element connects to a user's body member and a linkage between the connection element and ground. The linkage includes means for powering at least three independent freedoms of the connection element relative to ground and means for maintaining at least one independent freedom of the connection element relative to ground free of power. Up to three independent freedoms of the connection element may be maintained free of power, and up to five independent freedoms may be powered. Other aspects of the invention include a two actuator counter-balance for controlling a point on a link. The invention also includes apparatus for establishing a virtual, switch, which presents to the user the force and displacement relationship of a spring switch.

Abstract: The present invention relates to an apparatus for a Robust CMM Arm with Exoskeleton is provided comprising an Internal CMM Arm and an Exoskeleton driving the Internal CMM Arm through a plurality of transmission means such that one or more internal volumes are sealed against ingress of solid objects and fluids. It also relates to a haptic control of an RCA.

Abstract: An object of the invention is to provide a servo control device capable of making zero the positional deviation the positional deviation at a constant speed as well as the positional deviation at a constant acceleration or at constant acceleration and jerk, thereby providing a high-precision follow-up response. In order to solve this problem, the servo control device according to the invention includes a position controller (3) for generating a speed command that matches the motor output with a target position, a feed-forward controller (4) for adding a signal obtained by multiplying the differential of a target command by a gain and a signal obtained by multiplying the second-order differentiation of the target command by a gain and generating a speed feed-forward signal, and a speed controller (2) for performing I-P or PI control of the motor (1).

Abstract: A Bemf detect circuit is configured for modeling Bemf error via calculation of time correlations associated with two or more different non-calibrated sense resistor gain values to derive a calibrated sense resistor gain value. A method is provided for calibrating a Bemf detector circuit by setting a sense resistor gain to a plurality of different gain values, observing Bemf sample values for each of the gain values, and deriving a calibrated gain value by non-iteratively modeling the relationship between the gain values and the associated Bemf sample values.

Abstract: A human-machine interface assembly includes a user interface, a first motor, a second motor, a first sector gear, and a second sector gear. The user interface is configured to rotate about a first rotational axis and a second rotational axis that is perpendicular to the first rotational axis. The user interface is responsive to an input force to rotate about one or both of the first and second rotational axes. The first motor is disposed apart from the first rotational axis and generates a drive force about a third rotational axis that is parallel to the first rotational axis. The second motor is disposed apart from the second rotational axis and generates a drive force about a fourth rotational axis that is parallel to the second rotational axis. The first sector gear is coupled between the first motor and the user interface, and the second sector gear is coupled between the second motor and the user interface.

Abstract: An information distribution system capable of presenting an image photographed by a moving body, such as a robot or vehicle, selected by a user. The information distribution system includes moving bodies, local managers, and a global manager. When a user requests a connection with one of the moving bodies to the global manager through a portable terminal such as a portable phone, a menu generation section of the global manager generates a menu screen, and sends it to the portable terminal. The user selects one from the moving bodies through the menu screen, so that the portable terminal of the user connects with the selected moving body. An image photographed by a camera of the moving body is sent to the local manager, and information related to the image is superimposed on the image. Consequently, the superimposed image is sent to the portable terminal.

Abstract: An active human-machine interface system is implemented without a force sensor. The system includes a user interface that is configured to receive user input and, upon receipt thereof, to move to a position. A position sensor is coupled to the user interface and is operable to sense user interface position and supply a position signal representative thereof. A motor is coupled to the user interface and to receive motor current. In response to the motor current the motor supplies a feedback force to the user interface at a magnitude proportional to the motor current. A control circuit is coupled to receive at least the position signal and a signal representative of the motor current and controls the motor current supplied to the motor.

Abstract: The invention is directed to a method and an arrangement for signalizing the controlled deactivation of an assistance system during operation of motor vehicles (10) which are steerable by a steering manipulation device (36). The method is characterized in that the signalization takes place via a touch-sensitive signal generated in a controlled manner in the steering manipulation means (36). For this purpose, the arrangement includes actuating means (38, 78) which impresses a touch-sensitive signal on the steering manipulation device (36) with the signal being generated in a controlled manner.

Abstract: Disclosed is a control element or switching element that is provided with elements which electrically or chemically respond to the sense of touch, for example in a steering wheel. The elements are used for supplying the driver who touches the elements with warnings and/or information about the state of the vehicle or traffic. Interactive functions can be connected thereto, by means of which replies by the driver can be detected and processed. The driver can consequently cause the information system of the vehicle to also represent the warning information in an optical manner, e.g. in corresponding control lights on the dashboard, at a desired time.

Abstract: A position control device for causing a position of a control system, including a servomotor and a moving body driven by the servomotor, to track a command value. The position control device includes a sliding mode controller for receiving command position r and state variable x of the control system and for providing a control input u to the servomotor. State variable x is expressed as follows: x = [ ? ? . ] , where ? is feedback position and {dot over (?)} is feedback velocity. The position control device also includes a disturbance variable compensator for compensating control input u based on feedback velocity {dot over (?)}.

Abstract: There is provided a synchronous control device for driving the same control object with two servomotors. The synchronous control device detects the physical quantity that represents the difference between the forces on the two servomotors, and, on the basis of the detected value, reduces the force that acts between the two servomotors.

Abstract: A configuration system for an intelligent assist system is provided. The intelligent assist system includes a module, and a computational node on the module. The configuration system includes a host computer system capable of executing a stored program. The host computer system is in communication with the computational node via a communication link. The system also includes a graphical user interface enabling a user to manipulate objects related to the module or the computational node, and a plurality of visual indicators corresponding to a status of the module, the computational node, or the communication link.

Abstract: A setting device of a force feedback type has an operating unit commonly used to set a plurality of control items of an electronic device. To provide a different sensation to the operating unit depending on the control items, a force feedback pattern for an airflow rate setting is provided to a rotary knob, which is the operating unit, so that an operation of the rotary knob to rotate beyond an upper limit or a lower limit of an airflow rate range is restricted, and a force feedback pattern for the air outlet setting is provided to the rotary knob so that a rotational operation of the rotary knob is not restricted.

Abstract: The invention relates to a device for controlling an engine, in particular of an aircraft. The device has at least one throttle and a regulating device for additionally controlling the throttle automatically. A displacement of the throttle is transmitted permanently, in a direct or indirect manner to a position sensor.

Abstract: An intelligent assist system having a modular architecture, coordinated by electronic communication links between the modules, is provided. Motion modules provide an assist upon actuation, and are in communication with computational nodes. Communication links between at least two of the computational nodes carry information between the nodes that actuate a motion module.

Abstract: A magnetic flux produced by the current of a motor is detected by means of a Hall element, and an infinitesimal current proportional to the actual current of the motor is outputted. The outputted infinitesimal current is run through a resistor, and a potential difference across the resistor is detected by a ?? modulator circuit. The motor is subjected to feedback control based on the potential difference detected by the ?? modulator circuit.

Abstract: An intelligent assist system having a modular architecture, coordinated by electronic communication links between the modules is provided. A multi-function hub for use in the assist system includes a physical interface for providing mechanical support within the assist system. The hub can implement controlled functions. Furthermore, the hub can include an input/output (“I/O”) interface for communication to computational nodes.

Abstract: A system is described for the controlled propulsion of a transporting device including at least two drive wheels propelled by electromotive units, in which system at least two drive wheels are each propelled by independent electric motors; each electric motor receives electric power through an independent power amplifier which amplifies electric signals produced by sensor devices; the sensor devices detect a mechanical force applied on a push and pull element, and convert the mechanical force into electric signals which indicate the degree and the direction of the mechanical force applied on the push and pull element, and the amplifier amplifies the signal in accordance with a factor which is a function of the weight that the trolley has to move and it feeds the electric motor so it can power the drive motor in accordance with a torque corresponding to the movement ordered through the sensor devices.

Abstract: The invention is an apparatus for physically exchanging a force with a user in an environment local to the user. A connection element connects to a user's body member and a linkage between the connection element and ground. The linkage includes means for powering at least three independent freedoms of the connection element relative to ground and means for maintaining at least one independent freedom of the connection element relative to ground free of power. Up to three independent freedoms of the connection element may be maintained free of power, and up to five independent freedoms may be powered. Other aspects of the invention include a two actuator counter-balance for controlling a point on a link. The invention also includes apparatus for establishing a virtual, switch, which presents to the user the force and displacement relationship of a spring switch.

Abstract: The invention relates to a scanner, wherein a position of a moveable part of the scanner is adjusted by inputting a command variable which changes repeatedly in the same manner. A command signal corresponding to the command variable is supplied to a controller (3), the controller (3) being constructed for correcting a setpoint deviation in the presence of a command variable which is constant in time. A control error of the controller (3) which arises from the change in the command variable is corrected by evaluating a setpoint deviation of the position of the moveable part or an equivalent variable, obtaining from this a correction signal and changing an output signal of the controller (3) by using the correction signal.

Abstract: A system for tele-operating a robot in an environment includes a user interface for controlling the tele-operation of the robot, an imaging device associated with the robot for providing image information representative of the environment around the robot, means for transmitting the image information to the user interface, means for converting the image information to a user-perceptible image at the user interface, means for designating one or more waypoints located anywhere in the user-perceptible image towards which the robot will move, the waypoint in the user-perceptible image towards which the robot will first move being designated as the active waypoint using an icon, means for automatically converting the location of the active waypoint in the user-perceptible image into a target location having x, y, and z coordinates in the environment of the robot, means for providing real-time instructions to the robot from the user interface to move the robot from the robot's current location in the environment to

Abstract: An intelligent assist system having a modular architecture, coordinated by electronic communication links between the modules. Modules for motion, computation, interface, and programming are disclosed in exemplary embodiments.

Abstract: A method and system for controlling an intelligent assist device, robot, or other powered system that is partially or fully directed by the intent of a human operator. The method and system includes measuring a force or motion imparted by the human operator to a control. The measurement is determined with respect to the motion of the machine at a point of the machine that allows the benefit of collocation of sensing and actuation, or of approximation of such collocation. The system includes a support attached to the machine at the beneficial point, and a plurality of sensors to measure the force, torque, or motion imparted by the human operator to the support with respect to the beneficial point. The method and system provide improved stability of control of the system, and improved responsiveness to the intent of the human operator.

Abstract: A split detent tactile cueing vehicle control system (10) for a vehicle (11) is provided including an active control inceptor system (12). The active system (12) includes a control inceptor (22) having a plurality of positions and a position sensor (42) that generates a control inceptor position signal. The tactile cueing system (10) also includes a plurality of vehicle performance sensors that generate a plurality of vehicle performance signals. A flight controller (20) is electrically coupled to the position sensor (42) and the plurality of vehicle performance sensors, and generates a control inceptor actuation signal by applying a tactile cueing model having a split detent and in response to the position signal and the plurality of vehicle performance signals. A method of performing the same is also provided.

Abstract: Methods of remote control of a mobile robot and an intuitive user interface for remotely controlling a mobile robot are provided. Using a point-and-click device (405), the user is able to choose a target location (430) within a heads-up display (400) toward which to move a mobile robot. Additional graphical overlays (410 & 412) are provided to aid the user in navigating even in systems with asynchronous communication.

Abstract: A bridge surface preparation, maintenance and painting system has a truck-mounted man lift with an extensible platform on which robot arms and cameras are mounted. Inflatable bags isolate the area of the bridge being worked on, and an apron catches debris such as from sand blasting. An operator sits at a remote control console on a truck, directs the man lift platform into position, controls the inflating of the barriers and operates and guides the robot arms through master-slave controls while watching video displays. The machine is used for surface preparation, undercoating, finish coat painting and bridge inspections.

Abstract: A force feed back supply apparatus having a force feed back supply unit which is held by or mounted on an operator, and a force feed back generating unit for providing the force feed back supply unit with the load corresponding to an operation or the like of the operator, includes a clutch mechanism interposed between the force feed back supply unit and the force feed back generating unit; detector for detecting the position and orientation (attitude) of the force feed back supply unit with respect to the force feed back generating unit; and a controller for controlling the force feed back generating unit on the basis of the detection result of the detector, wherein when a force feed back is supplied, the clutch mechanism is set to be coupled between the force feed back supply unit and the force feed back generating unit, and when no force feed back is supplied, the clutch mechanism is set to be uncoupled between the force feed back supply unit and the force feed back generating unit and the controller contro

Abstract: A stage device includes a reaction-force-discharging structure in which a stationary member of a driving mechanism configured with a linear motor and the like disposed in a wafer chamber is connected to an external frame while maintaining the wafer chamber in a hermetic state. When a wafer stage is driven by the linear motor, a reaction force generated by driving the stage is applied to the stationary member. The reaction force is discharged to, e.g., a floor by the reaction-force-discharging structure via an external frame. For example, when the wafer chamber is set to a predetermined atmosphere of gas (including air from which organic substances and the like have been removed), the reaction force caused by driving the wafer stage can be discharged to the outside while maintaining the predetermined atmosphere. In an exposure apparatus using the stage device, accurate exposure is possible by reducing effects of vibration to the greatest extent possible.

Abstract: The invention relates to a rotary controller for electrical or electronic apparatuses (21, 22, 23), having a rotating knob (10). In order to offer the user a reference position of the rotating knob (10), with a simple design of the rotary controller, when making a selection between various options or when setting parameters, the invention provides a controllable latching and locking device (15), by means of which the rotating knob (10) can be locked selectively, in order to provide a stop for the rotary movement.

Abstract: The invention is an apparatus for physically exchanging a force with a user in an environment local to the user. A connection element connects to a user's body member and a linkage between the connection element and ground. The linkage includes means for powering at least three independent freedoms of the connection element relative to ground and means for maintaining at least one independent freedom of the connection element relative to ground free of power. Up to three independent freedoms of the connection element may be maintained free of power, and up to five independent freedoms may be powered. Other aspects of the invention include a two actuator counter-balance for controlling a point on a link. The invention also includes apparatus for establishing a virtual, switch, which presents to the user the force and displacement relationship of a spring switch.

Abstract: A numerical control apparatus for the numerical control of a roll grinding machine comprises a flaw detecting means for scanning the entire surface of a roll (11), provided with an ultrasonic detecting head (23) for detecting flaws formed in the surface of the roll (11), a command generating means for generating cross-feed commands to repair detected flaws on the basis of flaw information about the positions and levels of the detected flaws, a control means for executing a first shaft position control operation on the basis of the cross-feed command to position the grinding wheel at a position with respect to a Z-axis corresponding to the position of the flaw by moving the wheel spindle stock in parallel to the axis of the roll and a second shaft positioning control operation to cross-feed the grinding wheel in parallel to an X-axis, and a decision means for deciding whether or not the flaw has been completely repaired and invoking the next cross-feed command if the flaw has been completely repaired.

Abstract: A haptic pointing device includes a plurality of rigid, elongated proximal members, each connected to a separate rigid, elongated distal member through an articulating joint. The other end of each proximal member is coupled to an actuator such as a motor, causing that member to swing within a separate plane perpendicular to the shaft of the motor in response to a control signal. An end-effector is interconnected to the second end of each distal member through an articulating joint, such that as the actuators move the proximal members, the end-effector moves in space. In a preferred embodiment, the device includes at least three proximal members and three distal members, and the end-effector is coupled to a user-graspable element such as a stylus which retains a preferred orientation in space as the members are driven by the actuators.

Abstract: Master and slave servo control circuits 2a and 2b are configured with servo controllers 3a, 3b, servo amplifiers 4a, 4b, servo motors 5a, 5b, feedback detectors 6a, 6b and error detectors 7a, 7b, and the servo motors 5a, 5b are mechanically interlocked and connected to a load. At a location upstream from the servo amplifier 4b, a torque command value selector 21 is provided; when the error detector 7a does not detect an error in the servo control circuit 2a, the selector switches so that the servo amplifier 4a and the servo amplifier 4b both receive a torque command value from the servo controller 3a, and when the error detecter 7a detects an error in the servo control circuit 2a, the selector switches so that the servo amplifier 4b receives a torque command value from the servo controller 3b.

Abstract: A stage apparatus includes a base having a reference plane, a stage mounted on the base, a plurality of static-pressure bearings forming a gap between the reference plane and the stage, a plurality of preloading mechanisms producing a preload between the stage and the reference plane, a guideless motor for driving the stage, and a controller for controlling driving of the stage in (i) at least one of a direction perpendicular to the reference plane and in a tilting direction by controlling at least one of the static-pressure bearings and the preloading mechanism, and (ii) in a direction within the reference plane by the guideless motor. Positioning of the stage in a Z-direction and in tilting directions can be carried out by electromagnets and air pads. Positioning in directions (X, Y, &thgr;) within a plane parallel to the reference plane of the base can be accomplished by guideless motors.

Abstract: Beginning with a successive commanded end-effector destination shift, the method of the invention, which includes a calculation corresponding to a special algorithm of inverse kinematics using the Jacobi Matrix in the control of a manipulator, effects an optimization of weighted criteria (energy criteria, acceleration criteria and reference-position criteria) in a real-time cycle while reliably maintaining all path limitations and resulting in an optimized acceleration behavior. The method of the invention can be used in interactive path guidance of a manipulator and/or as a modular component of a superordinate task, such as for force-control objectives.

Abstract: A scanning exposure apparatus includes a projection optical system, a reticle stage for scanningly moving a reticle relative to the projection optical system a wafer stage for scanningly moving a wafer relative to the projection optical system, in a timed relation with the reticle scan movement, and a holding mechanism for holding the reticle on the reticle stage during the reticle scan movement. The holding mechanism includes a first mechanism for confining an end edge portion of the reticle in a scan direction and a second mechanism for pressing the reticle in a direction perpendicular to a pattern surface of the reticle.

Abstract: A control system (10) for a door operator (12) for moving a door includes a position sensor (54) to be coupled to the door (28) for sensing the position of the door and generating a position signal. An acceleration sensor (48) is to be coupled to the door for sensing the acceleration of the door (28) and generating an acceleration signal. An integrator (50) integrates the acceleration signal to generate a first velocity signal. A differentiator (56) differentiates the position signal to generate a second velocity signal. A blending filter (42) blends the first and second velocity signal to generate a filtered velocity signal, and a controller (32) regulates the velocity of the door (28) in response to the time and position of the door in a door open or close operation.

Abstract: A device for actuating a controlled member of an aircraft includes an intentional control member for actuation by the pilot, a computer for piloting on the basis of the action of the pilot on the intentional control member, a controlled member actuator for actuating the controlled member under control of the computer and a slaving device for slaving the position of the intentional control member to the position of the controlled member.

Abstract: Apparatus is provided to extend the number of active degrees of freedom of haptic interface to provide the user with the feel of a tool which is cantilevered over obstacles or which experiences frictional drag along its shaft. This is accomplished by providing two additional active degrees of freedom while not limiting the rotation or translation of the handle that the user is grasping. The apparatus constrains, through a 4 degree of freedom gimbal, the shaft of the tool handle, whose tip is controlled by another 3 spatial degree of freedom haptic device. The shaft of the tool slides and rotates in a sleeve bearing or collar which is mounted in a 2 degree of freedom gimbal. The gimbal is rigidly connected to a 2 degree of freedom parallel planar manipulator, with both degrees of freedom of the planar manipulator being powered by actuators used to generate the requisite haptic forces.

Abstract: An accelerator device is used for electromotive vehicles which has an electric motor adapted to cause the vehicles to move forwards and backwards. The accelerator device includes an accelerator pedal depressible to swing between a rest position and a most depressed position. Operatively connected to the pedal is an elongated pliable strip which is slidable along a predefined moving way and carries a permanent magnet. A plurality of magnetoelectric sensors are arranged along the moving way of the strip with a substantially equal spacing from one another, each of the sensors capable of generating, when left deactivated, a pedal position signal of first logic level and activatable by the magnetic flux of the permanent magnet to produce a pedal position signal of second logic level as the permanent magnet moves over and above the respective one of the sensors.

Abstract: A passive constraint device for implementing a programmable virtual constraint surface, comprises one or more non-holonomic kinematic transmission element for coupling velocities of motion and having a steering angle. A user moves the handle of the passive constraint device relative to the virtual surface. A steering motor sets the steering angle of the non-holonomic element in response to the proximity of the handle to the virtual surface. When in contact with the virtual surface, the steering angle is set so as to prohibit any motion which would penetrate the surface. When not in contact with the virtual surface, the steering motor adjusts the steering angle in response to the user's applied forces, to provide apparent freedom of motion to the user.

Abstract: The present invention relates to a system for coupling at least two control columns (2A, 2B) of a control device (DC) of a machine, especially an aircraft. The coupling system includes for each of the columns (2A, 2B), at least one operating member (13A, 13B, 14A, 14B) capable of making the column (2A, 2B) tilt about an axis, and a calculation unit (CAL) receiving information relating to the position of tilt of the columns (2A, 2B) and generating, when at least one of the columns (2A, 2B) is operated, tilt commands which are transmitted to the operating member (13A, 13B, 14A, 14B) of the other column (2A, 2B).

Abstract: An apparatus and method for physically exchanging a force with a user in a user-local environment. The apparatus includes a user connection element and a linkage physically linking the user connection element to a reference. The linkage provides at least six independent degrees of freedom to the user connection element. The linkage has an actuator system which powers at least three degrees of freedom of the user connection element, while at least three degrees of freedom remain unpowered. The method includes providing an apparatus which includes a user connection element and a linkage physically linking the user connection element to a reference, the linkage providing at least six independent degrees of freedom to the user connection element. The linkage of the apparatus provided has an actuator system which powers at least three of the six independent degrees of freedom relative to the reference.

Abstract: The computer-aided design system of the present invention is characterized in that a grasping force sensor 4 is mounted on that operating bar 3 at the front end of a manipulator 1 which is grasped directly and operated by an operator, and that the mechanical response characteristics of the system are varied on the basis of an output from the grasping force sensor 4. That is, the rigidity on the part of the manipulator is increased in response to a high grasping force during operation, since the rigidity of the hand is also high; and the rigidity on the part of the manipulator is decreased for a low grasping force during operation, since the rigidity of the hand is also low. In scenes in which a space on a computer screen defining no shapes is crossed by a cusor on the screen, a weak grip will lower the rigidity on the part of the manipulator, thus achieving the feeling of a smooth operation.

Abstract: A method and apparatus automatically associate a sensed mechanical parameter to a range of motor velocity for controlling the rotational velocity of a motor driving a medical instrument. The method and apparatus sense or measure the mechanical parameter whose value, controlled by a human operator, through for example, a footpad, can be measured and converted to a digital signal. The method and apparatus, in response to the measured sensed mechanical parameter, automatically scale the range of parameter values to a new range of motor velocity values thereby adjusting, to the mechanical displacement (force or distance) with which the user is most comfortable. The transformation also provides deadband values around the minimum and maximum motor velocities so that maximum motor velocity is not "chased" and minimum motor velocity is not sensitive to small perturbations due to thermal effects and other events which may affect the mechanical sensor output.

Abstract: A rudder bar system for a helicopter controlled in yaw by acting on the tail rotor or an equivalent device has a capability, as a function of the parameters representative of the current flight status of the helicopter, of either automatically continuously recentering the forces on the rudder bar, which cancels out the residual static forces and gives the pilot a tactile sensation close to that given by a friction-type rudder bar, or allowing the pilot fully to feel the countering action of an elastic return device such as a spring.

Abstract: A control device with a control stick, wherein the control stick is moved by an irreversible actuator controlled by a computer, and the computer controls the position of the actuator and thus the movement of the control stick, and slaves the control column position to the force applied, in accordance with force data, from a force sensor, and position data, from a position sensor, through use of a position vs. force law entered in the computer.

Abstract: A movable stage apparatus and an exposure system including a moving stage apparatus, includes a movable member capable of being driven by a driving mechanism, and first and second sets of fluid bearings. The first set of fluid bearings supports the movable member. The second set of fluid bearings is connected to a plurality of driving elements. The plurality of driving elements are connected to the movable member and are displaceable in a direction in which the movable member is supported by the first set of fluid bearings. The second set of fluid bearings supports the movable member. Also provided is a controller for applying a voltage to the plurality of driving elements so as to compensate for the postutre of the movable member when the posture of the movable member changes in response to being driven by the driving mechanism. The system further includes an exposure apparatus for exposing an object to be exposed which is mounted on the movable member.

Abstract: A hand controller system which provides the proper feel of the hand controller during aircraft operation. In both non-redundant and redundant embodiments, torque, and position measurements are made from the hand controller movements and processed to provide a feedback to a control motor in mechanical connection with the hand controller. The system includes self-monitoring of the motor, as well as the signals provided by the position, and torque sensors. Connections are provided from the hand controller system so that cross-coupling may be provided between the pilot's and copilot's hand controllers.

Abstract: Both a pneumatic, linear actuator operating as a slave actuator and a master linear actuator formed by an electric motor driven screw mechanism are linked to drive a load. The high accuracy master linear actuator has a conventional control system which dominates the control of load position or other control variable. A force sensor detects the force applied to the load by the master actuator or the force is calculated by a computer and the sensed force signal is applied to a slave actuator control to cause the slave to apply a supplemental force, typically considerably greater than the master actuator force, to the load as a function of the master actuator force. This obtains the high accuracy characteristic of the master actuator system simultaneously with the high force characteristic of the slave actuator.