Abstract: A method of adjusting a force control parameter includes a first step of moving a robot arm based on first information on work start position and orientation of the robot arm and a candidate value of a force control parameter, and acquiring second information on a working time taken for the work and third information on a force applied to the robot arm during the work, and a second step of acquiring an updated value obtained by updating of the candidate value of the force control parameter based on the acquired second information and third information, wherein the first step and the second step are repeatedly performed with noise added to the first information until the acquired working time or force applied to the robot arm converges, and a final value of the force control parameter is obtained.

Abstract: A method of driving an actuator using a shape memory alloy is provided. An impact-driven actuator is activated by a pulse voltage generated by an action of a transistor. A keyboard outputs a key event at the timing of an input operation. A stress monitoring unit calculates a stress amount of an impact-driven actuator based on parameters of a key event and a pulse voltage. A stress adjustment unit changes the parameter of the pulse voltage when the stress amount reaches a permissible value. The parameter may be a wave crest value or a pulse width of the pulse voltage. The stress adjustment section is also able to stop the action of the impact-driven actuator in response to a key event corresponding to a break code.

Abstract: A rotary apparatus includes a motor, a plurality of gears, and a sensor configured to detect a rotation angle of one of the plurality of gears. The sensor includes a first connection terminal electrically connecting to the outside, and a base portion. The first connection terminal is disposed at the base portion. A second connection terminal is disposed at the base portion.

Abstract: Disclosed herein is a Pulse Width Modulation (PWM) controller. The PWM controller includes a plurality of Field Effect Transistors (FETs) and an FET driver. A comparator compares a current flowing through the FETs with an overcurrent reference value, and microcomputer controls a motor and a circuit protection function, and turns off the FET driver when the current flowing through the FETs is greater than the overcurrent reference value as a result of comparison by the comparator.

Abstract: The present invention provides a method of computing a correction value for the machine tool having two or more translational axes and one or more rotational axes for correcting error in a position and an orientation of the tool with respect to a workpiece due to the geometric error. The method includes a rotational axis correction value computing step (S3) for computing a correction value for the rotational axis by use of a geometric parameter representing the geometric error, and a translational axis correction value computing step (S4) for computing a correction value for the translational axis by use of a command value for each of the rotational axes, a command value for each of the translational axes, and the geometric parameter.

Abstract: A torque detection device includes: a torsion bar that couples a first shaft to a second shaft; a magnet that is fixed to the first shaft; and a pair of magnetic yokes that are fixed to the second shaft and that are arranged to face each other in an axial direction. Each of the magnetic yokes includes a yoke ring and a plurality of lugs that are arranged in a circumferential direction on the corresponding yoke ring. Each yoke ring includes an extending portion that extends radially outward from base portions of the lugs, and a bent portion that is bent in the axial direction from a radially outer end portion of the extending portion. The outer size of the pair of magnetic yokes in the axial direction is larger than or equal to the length of the magnet in the axial direction.

Abstract: Systems and methods for estimating an inertia and a friction coefficient for a controlled mechanical system are provided. In one or more embodiments, an inertia estimator can generate a torque command signal that varies continuously over time during a testing sequence. The velocity of a motion system in response to the time-varying torque command signal is measured and recorded during the testing sequence. The inertia estimator then estimates the inertia and/or the friction coefficient of the motion system based on the torque command data sent to the motion system and the measured velocity data. In some embodiments, the inertia estimator estimates the inertia and the friction coefficient based on integrals of the torque command data and the velocity data.

Abstract: A torque detection device includes: a torsion bar that couples a first shaft to a second shaft such that the first shaft and the second shaft are rotatable relative to each other; an annular magnet that is fixed to the first shaft; a pair of magnetic yokes that are fixed to the second shaft and that are arranged to face the magnet; and Hall ICs. Each of the magnetic yokes has a plurality of lugs arranged at equal intervals in a circumferential direction, and each lug becomes narrower toward its distal end, and has a curved profile with rounded corners when viewed from a radial direction of the corresponding magnetic yoke.

Abstract: A torque detection device includes: a torsion bar that couples a first shaft to a second shaft; a magnet that is fixed to the first shaft; and a pair of magnetic yokes that are fixed to the second shaft and that are arranged to face each other in an axial direction. Each of the magnetic yokes includes a yoke ring and a plurality of lugs that are arranged in a circumferential direction on the corresponding yoke ring. Each yoke ring includes an extending portion that extends radially outward from base portions of the lugs, and a bent portion that is bent in the axial direction from a radially outer end portion of the extending portion. The outer size of the pair of magnetic yokes in the axial direction is larger than or equal to the length of the magnet in the axial direction.

Abstract: An object of the present invention is to provide a mechanically and electrically integrated type electronic control apparatus which can be embedded in a compact mechanical part, and has a compact structure while having a high wiring freedom, a high heat dissipation and a high reliability. In a mechanically and electrically integrated type electronic control apparatus provided with a control signal generating part, and an angular wiring member connecting the control signal generating part and a controlled part controlled by a control signal of the control signal generating part, installed within a conductive casing, at least the wiring member has a fixed hole, a surface including the fixed hole is coated in an insulative manner, and the fixed hole is fixed to the conductive casing mechanically while keeping an insulating property.

Abstract: A system and method for driving a drawer of a refrigerator and a refrigerator employing this system is provided. This system and method allows the drawer to substantially immediately and automatically stop when the drawer encounters an obstacle. This type of automatic control of the drawer may enhance the safe operation of the drawer, prevent injuries to users, and prevent overload and subsequent malfunction of a drive motor used to move the drawer.

Abstract: A method to control medical equipment that moves along at least one axis or performs joint movement is provided. While the medical equipment is passively moved as operated by the operator, the operation intention of the operator is determined using a force sensor, a torque sensor, or the like, and motor control is performed taking into consideration the determined operation intention to reduce load (or drive power) of the operator. To accomplish this, the method determines a direction and magnitude of force that an operator applies to the medical equipment to move the medical equipment and generates auxiliary force having a magnitude proportional to the force applied by the operator and having the same direction as the direction of the force applied by the operator such that the medical equipment is easily moved.

Abstract: A system and method for driving a drawer of a refrigerator are provided. This system allows a drawer to be automatically withdrawn from and/or inserted into a main body of the refrigerator. This system also allows a drawer which has been stopped during the withdrawal process to be further withdrawn from the main body so as to complete action on a withdrawal command, or to be re-inserted into the main body, so as to reduce cool air loss.

Abstract: A motor control apparatus includes a steering column having inserted therein a steering shaft to which steering torque is transmitted, a reduction gear box coupled to the steering shaft, and an electric motor that transmits a steering assisting force to the steering shaft via a reduction mechanism in the reduction gear box. The electric motor and its control unit including a control board mounted with a control circuit, are provided side by side in the reduction gear box. A connection terminal of the electric motor is electrically connected to the control unit directly. This minimizes a connection distance between the control unit and the electric motor.

Abstract: The invention relates to a device for controlling the movement of a plurality of moveable furniture parts which can be moved in a driven manner relative to a stationary furniture part by means of a drive unit via a monitoring unit for monitoring the movement of the moveable furniture parts. According to the invention, the monitoring unit is designed such that, as long as one moveable furniture part is being moved in a driven manner on a predetermined movement section, none of the other furniture parts which can be moved in a driven manner are moveable in a driven manner. The invention also relates to a piece of furniture and to a method for configuration of a device for controlling the movement of moveable furniture parts.

Abstract: An article of furniture includes a drive device for moving a movable furniture part. The drive device includes an electric drive unit and a coupling device for at least temporarily transmitting a force of the electric drive unit to the movable furniture part, and the coupling device has a drive and a drive output. Operating between the drive and the drive output are coupling elements by which, in a first operating position, a clamping connection between the drive and the drive output and thus coupling between the drive and the drive output can be produced, and, in a second operating position, the coupling elements are movable into a position in which the drive and the drive output are not coupled.

Abstract: Provided is a power steering apparatus capable of suppressing an abrupt change in steering force and preventing a deterioration in steering feeling even in the event of a transition from power steering to manual steering. The power steering apparatus includes a torque sensor, a motor of a permanent magnet field type, and a controller having a motor driving unit and an abnormality monitoring unit, for controlling the driving of the motor. The motor driving unit includes an inverter for driving the motor, and a drive signal generating unit for calculating a target current caused to flow through the motor and outputting a drive signal of the inverter based on the target current. The abnormality monitoring unit includes an abnormality processing unit for constituting a closed-loop circuit including the motor in stopping the driving of the motor.

Abstract: An active material actuator adapted for use in a circuit includes an active material member, and a piezoelectric or piezoresistive element or otherwise force sensing device, wherein the element or device is communicatively coupled to the member and operable to vary the current within the circuit when the member is caused to achieve a predetermined stress, such that, in one aspect, the element presents an overload protection mechanism.

Abstract: Disclosed is an assembly comprising at least two electric drive units (4) for respectively driving one of at least two drawers (2) which are movably mounted within a common furniture carcass (3). A measuring instrument (10) is assigned to each drive unit (4) in order to detect a force (F) that a user applies to the respective drawer (2). The inventive assembly further comprises at least one control or regulation device (9) for controlling or regulating the drive units (4). The measuring signals of the measuring instrument (10) can be fed to the control or regulation device (9) while the control or regulation device (9) can trigger the associated drive unit (4) after receiving a predetermined measuring signal from one of the measuring instruments (10).

Abstract: A drive unit of a pressure device, such as a welding gun, includes a piezoelectric type load cell adapted to be arranged in an easily attached and removed manner and to have relatively small capacity. The drive unit includes a through-hole 6, formed in a rotary shaft 5 of a drive motor 1, which is a drive source, and a pressure shaft 10, configured to be able to move with a part thereof being in the through-hole 6. The rotary shaft 5 is rotatably supported by the bearing 7, and the piezoelectric type load cell 17 is sandwiched between a preload striker plate 18, through which the pressure shaft 10 passes, and a preload setting striker plate 19, through which the pressure shaft 10 passes with a preload exerted on the load cell 17.

Abstract: An arrangement with a movable portion of an article of furniture, in particular a drawer (3) or the like, includes a drive unit (5) and a regulating device (1) for regulating the drive unit (5). The arrangement has a preferably analog force measuring device (2), and the force measuring device (2) produces a force signal which is characteristic for forces (20) applied from the exterior to the movable portion (3) of the article of furniture and which can be fed to the regulating device (1).

Abstract: To provide an electric power steering apparatus in which it is possible to minimize a connection distance between a control unit and an electric motor and surely prevent electric noise from mixing between the control unit and the electric motor as well as to minimize electric resistance and minimize an electric loss by directly connecting the control unit and connection terminals of the electric motor and a torque sensor. A motor control apparatus includes a steering column 3 having inserted therein a steering shaft 2 to which steering torque is transmitted, a reduction gear box 4 coupled to the steering shaft 2, and an electric motor 5 that transmits a steering assisting force to the steering shaft 2 via a reduction mechanism in the reduction gear box 4.

Abstract: A method and apparatus for estimating inertia wherein a load has a limited range of load travel, the method comprising the steps of identifying an intermediate position along the range of load travel that is separated from a first end of the range of load travel, with the load separated from a first end of the range of load travel, increasing a velocity of the electric motor from a first velocity, identifying when the load has reached the intermediate position, identifying the motor velocity at the intermediate position as a second velocity, detecting a first rate of velocity change from the first velocity to the second velocity and deriving an inertia value as a function of the first rate of velocity change.

Abstract: A controller for a die cushion mechanism includes: a spring element that is displaced according to force between the die cushion mechanism and a slide; a force instructor that instructs force; a force detector that detects force; and a speed instruction generator that generates a speed instruction of the servo motor, based on a force instruction value instructed by the force instructor and a force detection value detected by the force detector. The speed instruction generator generates the speed instruction by multiplying a force gain by a force difference determined from a difference between the force instruction value and the force detection value. The speed instruction generator changes the force gain, based on a spring constant corresponding value of the spring element determined from a force indicator that works between the slide and the die cushion.

Abstract: An arrangement having at least one movable furniture part, in particular having a drawer or the like, having at least one drive unit and at least one regulating device for regulating the at least one drive unit, wherein the arrangement (7) has at least one, preferably analog, acceleration measuring device (2), with the at least one acceleration measuring device (2) generating an acceleration signal that is characteristic of accelerations caused by forces applied to the at least one movable furniture part (3) from the outside and that may be supplied to the at least one regulating device (1).

Abstract: A controller includes a first data acquiring portion for acquiring a time constant of a position control circuit based on a position command value to a drive source and an actual position value, during operation of a controlled object; a second data acquiring portion for acquiring a rigidity value for the controlled object and a workpiece based on a force data obtained when the controlled object is brought into contact with the workpiece; and an automatic gain calculating portion for calculating a force control gain of a force control circuit from the time constant of the position control circuit acquired by the first data acquiring portion and the rigidity value acquired by the second data acquiring portion, under conditions where a time constant of the force control circuit is larger than the time constant of the position control circuit.

Abstract: A method and apparatus for estimating inertia of an electric motor that drives a load wherein the load has a limited range of load travel, the method comprising the steps of identifying an intermediate position along the range of load travel that is separated from a first end of the range of load travel, receiving a sensor signal from a sensor attached to the electric motor, with the load separated from a first end of the range of load travel, increasing a velocity of the electric motor from a first velocity as the load travels toward the first end of the range of load travel, identifying when the load has reached the intermediate position, identifying the motor velocity at the intermediate position as a second velocity, in response to the sensor signal, detecting a first rate of velocity change from the first velocity to the second velocity, acquiring a plurality of torque samples while the electric motor is changing velocity, each torque sample representing an amount of torque generated by the electric moto

Abstract: A hauling unit hauls a subject to bend or rotate the subject. A control unit outputs a control signal that corresponds to a target value that is input by an operating unit. The control unit controls a variation amount of the control signal output in a predetermined range including a position of the hauling unit in a state before the hauling unit hauls to be greater than a variation amount of the control signal output outside the predetermined range. A driving unit drives the hauling unit based on the control signal.

Abstract: An injection molding machine has a control device which controls an input to an incorporated motor. The control device sets a setting value a setting value of the motor to be held for a predetermined setting time. Additionally, the control device determines a reduction ratio which causes the setting value to be reduced according to passage of time, and controls the input to the motor based on the reduction ratio. Thereby, a power consumption of the motor is reduced.

Abstract: A method of driving a moveable part and, in particular, a drawer by a drive unit and, in particular, an electric drive unit. At least over a partial length of track (S2), forming part of the total track traversed by the moveable part, the force exerted on the moveable part by the drive unit is controlled at a predetermined level.

Abstract: A controller, for force-controlling a drive source of a controlled object, having a position control circuit inside a force control circuit in order to define a relative position of the controlled object to a workpiece, and a contact force occurred between the workpiece and the controlled object, the controller including a first data acquiring portion for acquiring a time constant of the position control circuit based on a position command value to the drive source and an actual position value, during operations of the controlled object; a second data acquiring portion for acquiring a rigidity value for the controlled object and the workpiece based on a force data obtained when the controlled object is brought into contact with the workpiece; and an automatic gain calculating portion for calculating a force control gain of the force control circuit from the time constant of the position control circuit acquired by the first data acquiring portion and the rigidity value acquired by the second data acquiring po

Abstract: A system for reducing torque disturbance includes a motor mechanically coupled to an endless belt. The motor is operable to drive the belt, and the belt has a seam that causes a torque disturbance to the system. The system includes a data structure having a set of values that indicates an amount of compensation for reducing the torque disturbance and a controller electrically coupled with the motor. The controller is configured to control the motor and reduce the torque disturbance based on the set of values in the data structure.

Abstract: A control parameter automatic adjustment apparatus acquires a movable range of a drive shaft of a drive system, and automatically generates a test movement program to automatically adjust a control parameter to the drive system even though the movable range changes.

Abstract: A method of avoiding collisions between a robot and at least one other object such as another robot is provided in which the user does not need to make any provisions in a robot program for avoiding collisions and defining common work-areas. Furthermore, the method allows for automatic configuration of the workcell from a collision avoidance standpoint. It determines automatically which components have potential collisions with which other components. Since the inventive method is based on predicting the configurations of the moving components over a period of time sufficient enough to allow the machines to stop safely and checks for interference, a priori knowledge of trajectories is not required. If a collision is predicted the machines are commanded to a stop on or off their paths. In this way the inventive collision avoidance method can also be used as a safeguard with other explicit methods.

Abstract: An arrangement with a movable portion of an article of furniture, in particular a drawer (3) or the like, with a drive unit (5) and with a regulating device (1) for regulating the drive unit (5), wherein the arrangement has a preferably analog force measuring device (2) and wherein the force measuring device (2) produces a force signal which is characteristic for forces (20) applied from the exterior to the movable portion (3) of the article of furniture and can be fed to the regulating device (1).

Abstract: A vibrating structure gyroscope having a vibrating structure (3) primary drive means (4) and secondary drive means (7) and primary pick-off means (2) and secondary pick-off means (6) is provided with a control system. The control system includes a primary closed control loop (1) for controllably varying the drive signal applied to the primary drive means (4), a secondary closed control loop (5) for controllably varying the drive signal applied to the secondary drive means (7) in order to maintain a null value of the secondary pick-off means (6) and means (30) for actively adjusting the scalefactor in the primary and secondary closed control loops (1, 5). The means (30) includes means (34) for dividing a rate response signal from the loop (5) by a signal indicative of the amplitude of the primary mode vibration. The output form the means (34) is filtered to provide an applied rate output.

Abstract: A vehicle lamp system 1 having a leveling mechanism 2 for controlling the posture of a reflector RF and a stepping motor 3 as a driving source of the leveling mechanism. The lamp system has a detector 5 which may determine whether an external force, such as a vibration or a shock is given to the reflector RF or if there is a possibility that the vibration or shock may be given to the reflector. A rotor is prevented from being deviated from the original position by exciting each phase coil of the stepping motor with the same excitation phase as the last excitation phase at the time when the stepping motor 3 was last driven or otherwise a coil in only one of the last excitation phases at the time when the stepping motor 3 was last driven, and before vibration or a shock is given to the reflector RF after the coils in the respective phases are totally set to a non-excited condition in the stepping motor 3.

Abstract: A system for maintaining a desired sealing force is provided, which incorporates a closed loop control system. The system includes a platen, which has a surface for making contact with one or more items to be sealed, a motor for producing a linear movement, a linkage coupled to the platen and the motor for transferring the linear movement produced by the motor to the platen, and a transducer coupled between the linkage and the platen for measuring the force applied to the platen via the linkage through the linear movement of the motor and producing a signal representative of the force measured. A motor controller produces a motor control signal, which is supplied to the motor for controlling the same. The motor control signal is used to control the linear movement produced by the motor. The motor controller further receives the feedback signal from the transducer, and correspondingly adjusts the value of the control signal used to control the magnitude of the linear movement.

Abstract: A method of controlling a powered manipulator (10) is disclosed. The powered manipulator (10) includes at least one motor (12), at least one force sensor (14) on a manual control handle (16) and a microprocessor (18) combined with the plurality of the force sensors (14) for controlling a powered manipulator (10) within physical limits of a workspace. The method comprises the steps of the operator imparting a force on the control handle (16), sensing the direction and magnitude of the force with the plurality of force sensors (14) and sending the force data to the microprocessor (18), processing the force data from the plurality of force sensors (14) with the microprocessor (18) to create movement commands for the powered manipulator (10) and moving the powered manipulator (10) in response to the movement commands from the microprocessor (18).

Abstract: A dynamic control system for a power-assist device has a statics formulator for determining a set of static torques for the lift system based on force data from the lift system. The control system further includes a dynamics formulator for determining a set of dynamic torques for the lift system based on joint data and the static torques. A static torque and a dynamic torque is therefore determined for each joint of the assist device. The control system also includes a torque summation module for summing the dynamic torques with the static torques to determine torque data for each joint of the lift system. The torque summation module applies the torque data to the lift system to achieve dynamic compensation within a substantially shorter response time. Thus, a method and system are presented for dynamically controlling a power-assisted lift system to continuously reduce human operator strain in a real-time mode.

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: The present invention relates to a robot path planning method for determining the path of a robot, taking into consideration the bending effect of the robot path when heavy tools are load onto the robot. Specifically, straight line P'-Q' to be actually drawn by the distal end of the robot tool is calculated by using the positions P and Q of the distal end of the tool at the start point and at the end point of the straight line recognized by the robot controller. And, the interpolation points H1', H2', H3', . . . are set on this line P'-Q'. Then, the bending amount .DELTA..theta.pj and .DELTA..theta.qj at the start point P' and at the end point Q' of this line P'-Q' are respectively determined. And, the bending amount at each interpolation point H1', H2', . . . are calculated from these bending amounts .DELTA..theta.pj and .DELTA..theta.qj, and the position on the line P'-Q' of each interpolation point. Then, the values obtained by subtracting from each interpolation point H1', H2', . . .

Abstract: A position control apparatus has a target setting unit for setting a target position in a direction of the control axis of the controlled object able to be moved in directions of a plurality of control axes by moving unit; a position control unit for independently positioning the controlled object to the target position in the direction of the control axis set by the target position setting unit; and a position correcting unit for correcting the target positions in directions of other control axes by compensation amounts for correcting positioning derivation in directions of other control axes occurring when positioning the controlled object to a first target position in the direction of one control axis among the plurality of control axes and then reversing the feed direction from that first target position and positioning to a second target position.

Abstract: A control system for a tuning fork gyroscope uses motor frequency to control motor amplitude. The tuning fork gyroscope has a drive signal input and an output signal from which motor frequency is determined. A phase/frequency detector generates an error signal by comparing the actual oscillation phase of the output signal with the phase of a reference signal from a crystal controlled frequency synthesizer. The error signal is filtered in a feedback loop control to reduce phase detector ripple. The output of the loop controller is then used to determine the appropriate drive signal to drive the error signal to a constant and maintain a predetermined oscillation frequency.

Abstract: An electric brake device includes a disc rotor which is rotatable together with a wheel of an automotive vehicle. An output rod is provided to press a friction pad onto the disc rotor so as to exert a braking force on the wheel. A brake motor is provided to generate a rotating force in response to an electric signal. A gear mechanism is provided to axially move the output rod relative to the disc rotor in accordance with the rotating force, such that the output rod is moved toward the disc rotor when the brake motor rotates in a forward direction, and the output rod is separated from the disc rotor when the brake motor rotates in a reverse direction. A load detection unit detects a load acting on an end of the output rod opposite to a position where the output rod presses the friction pad onto the disc rotor. A motor deceleration unit decreases the rate of rotation of the brake motor when the load detected by the load detection unit is above a reference level.

Abstract: A stator 3 of a motor 1 is pivotally supported on a stationary system 5 by an elastic member 28, 11a, 42 provided along the circumferential direction of the stator 3, and a detector 11 for detecting a rotational force of the stator 3 is provided to execute the control of stopping, accelerating, decelerating or reversing the operation of the motor 1 based on a detection signal from the detector 11. When the motor load is increased, transmission of torque from the action system 3 to the reaction system 4 of the motor 1 is cut off, and consequently the stator 3 itself of the motor 1 pivots with respect to the stationary system 5 as a reaction. In this stage, the detector 11 detects the rotational force of the stator 3 to stop, accelerate, decelerate, or reverse the operation of the motor 1.

Abstract: A mechanism for stopping an object to be swung in a predetermined stop position and holding the object in that position includes a temporary stopping unit for stopping the swing of the object in a temporary stop position before the stop position, a rotation complementing unit for complementarily further rotating the object from the temporary stop position to the stop position, and a holding unit for holding the object in the stop position.

Abstract: A method and apparatus are provided for controlling the operational characteristics of a motor. The method includes the steps of reading a plurality of optically encoded controller position signals, determining a motor control signal state and differential based thereon and outputting a motor control signal. The central operation of the method and apparatus is based on a motor control signal state diagram and the transitions therein. The apparatus includes a rotary digital optical encoder having a plurality of output signals, a programmable controller device and an output circuit. The programmable controller device includes motor control logic for determining the operational characteristics of a motor. The motor control signal may be either/or a pulse width modulated (PWM) or analog output. Additionally, described embodiments include an apparatus having logic for determining the directional characteristics of a motor.

Abstract: A power-assisted wheelchair wherein the power-assist for the wheels is based upon the manual force exerted on both of the wheels. The power-assist is continued for a brief time period after manual power input is stopped. The continuing assist is provided equally to each wheel so that the wheelchair will coast in a straight direction. The wheels of the wheelchair are readily detachable with the backing plate prime mover and transmission for driving the wheel.

Abstract: A tuning fork gyroscope has an in-plane position sensitive pick-off to which an AC or AC+DC bias is applied. Intermodulation is exploited to produce beat-notes between the applied frequency and the motor frequency at amplitudes proportional to motor amplitude, but unaffected by error sources such as spurious substrate charge accumulation. The beat-notes are used to control motor amplitude without the effects of charge accumulation.