Abstract: The present invention relates to a variable-torque magnetorheologically actuated prosthetic knee which utilizes a plurality of interspersed and alternating rotors and stators to shear magnetorheological fluid in gaps formed therebetween. Advantageously, by operating in the “shear mode” there is substantially no or negligible fluid pressure buildup or change. Moreover, the multiple MR fluid gaps or flux interfaces desirably allow for the production of a large torque at low speed—eliminating the need for a transmission—and also for a wide dynamic torque range. One embodiment of the invention allows the rotors and/or stators to close the gaps therebetween to create a frictional torque component, thereby forming a “hybrid” braking system which provides a total torque or damping which is a combination of viscous torque and frictional torque.

Abstract: Provided is a force-controlled hydro-elastic actuator, including a hydraulic actuator, having a connection to hydraulic fluid and including a mechanical displacement member positioned to be mechanically displaced by fluid flow at the actuator. A valve is connected at the hydraulic actuator connection and has a port for input and output of fluid to and from the valve. At least one elastic element is provided in series with the mechanical displacement member of the hydraulic actuator and is positioned to deliver, to a load, force generated by the hydraulic actuator. A transducer is positioned to measure a physical parameter indicative of the force delivered by the elastic element and to generate a corresponding transducer signal. A force controller is connected between the transducer and the valve to control the valve, based on the transducer signal, for correspondingly actuating the hydraulic actuator and deflecting the elastic element.

Abstract: In general, the invention features methods by which more than one client program connected to a network stores the same data item on a storage device of a data repository connected to the network. In one aspect, the method comprises encrypting the data item using a key derived from the content of the data item, determining a digital fingerprint of the data item, and storing the data item on the storage device at a location or locations associated with the digital fingerprint. In a second aspect, the method comprises determining a digital fingerprint of the data item, testing for whether the data item is already stored in the repository by comparing the digital fingerprint of the data item to the digital fingerprints of data items already in storage in the repository, and challenging a client that is attempting to deposit a data item already stored in the repository, to ascertain that the client has the full data item.

Abstract: Provided is a force-controlled hydro-elastic actuator, including a hydraulic actuator, having a connection to hydraulic fluid and including a mechanical displacement member positioned to be mechanically displaced by fluid flow at the actuator. A valve is connected at the hydraulic actuator connection and has a port for input and output of fluid to and from the valve. At least one elastic element is provided in series with the mechanical displacement member of the hydraulic actuator and is positioned to deliver, to a load, force generated by the hydraulic actuator. A transducer is positioned to measure a physical parameter indicative of the force delivered by the elastic element and to generate a corresponding transducer signal. A force controller is connected between the transducer and the valve to control the valve, based on the transducer signal, for correspondingly actuating the hydraulic actuator and deflecting the elastic element.

Abstract: The present invention relates to a variable-torque magnetorheologically actuated prosthetic knee which utilizes a plurality of interspersed and alternating rotors and stators to shear magnetorheological fluid in gaps formed therebetween. Advantageously, by operating in the “shear mode” there is substantially no or negligible fluid pressure buildup or change. Moreover, the multiple MR fluid gaps or flux interfaces desirably allow for the production of a large torque at low speed—eliminating the need for a transmission—and also for a wide dynamic torque range. One embodiment of the invention allows the rotors and/or stators to close the gaps therebetween to create a frictional torque component, thereby forming a “hybrid” braking system which provides a total torque or damping which is a combination of viscous torque and frictional torque.

Abstract: The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion.

Abstract: In accordance with the present invention, an electric vehicle drive control system is provided. The system of the present invention controls the supply of actuating power to an electric motor for driving the vehicle. One preferred embodiment of the system permits a user to temporarily override a previously selected maximum power usage level for the motor so as to permit the amount of power supplied to the motor to be increased to a higher maximum power usage level.

Abstract: Circuit supporting modules form a three-dimensional communication interconnect mesh. A first embodiment three-dimensional communication interconnect is a tetrahedral lattice having a regular, isotropic, three-dimensional topology in which each module connects to its four physically closest neighbors. The structure of the tetrahedral interconnect is isomorphic with a diamond lattice structure. In a second embodiment the interconnect is hexahedral. A characteristic of both is embodiments is that, although connections are made to plural other modules, the physical connections are made along the same direction.

Abstract: The invention provides an elastic actuator consisting of a motor and a motor drive transmission connected at an output of the motor. An elastic element is connected in series with the motor drive transmission, and this elastic element is positioned to alone support the full weight of any load connected at an output of the actuator. A single force transducer is positioned at a point between a mount for the motor and an output of the actuator. This force transducer generates a force signal, based on deflection of the elastic element, that indicates force applied by the elastic element to an output of the actuator. An active feedback force control loop is connected between the force transducer and the motor for controlling the motor. This motor control is based on the force signal to deflect the elastic element an amount that produces a desired actuator output force. The produced output force is substantially independent of load motion.

Abstract: A system for generating pulse width modulated signals is provided. The signals are generated in response to control and reference signals that are subject to noise-related interference. Signals erroneously generated as a result of the interference are suppressed from the final signals output by the system without reducing the duty cycle of the final output signals.

Abstract: An interface controlling digital communication between synchronous systems of unequal clock frequency. A phase locked loop generates one clock F.sub.m from the other F.sub.n by locking the phase of the two clocks at a beating period. Within the beating period, a precompiled set of valid and invalid communication clock cycles for each direction of communication are scheduled into lookup tables. The lookup tables generate outputs to a Set of registers for communicating data between the systems of unequal clock frequency.

Abstract: Circuit supporting modules form a three-dimensional communication interconnect mesh. Each module has fewer than six sets of connectors, preferably four. The preferred three-dimensional communication interconnect is a tetrahedral lattice having a regular, isotropic, three-dimensional topology in which each module connects to its four physically closest neighbors. The structure of the tetrahedral interconnect is isomorphic with a diamond lattice structure.

Abstract: A synchronized phase adjustment system provides relative synchronization of the clock oscillators in a mesh-connected parallel processor. Each node of a mesh contains an independent voltage controlled oscillator, and each node is linked to adjacent nodes by phase detectors. The phase differences between a node oscillator and the oscillators of adjacent nodes are combined by an input circuit the output of which is an average value applied to the node oscillator. The transfer function of the signal input to an oscillator relative to detected phase error indicates the restoring force (voltage) which is provided to adjust the phase of that oscillator. It is shown that a stable latch-up state in which all node phases of a mesh are not equal requires that one of the phase differences between two nodes is greater than .pi./2. Thus, the transfer function of the signal input to an oscillator is given a negative slope for phase differences having an absolute value between .pi./2 and .pi..