Abstract: A method of timing data sampling includes, in a data acquisition device, generating sampling intervals from a system clock of the data acquisition device, sampling data at the generated sampling intervals, and receiving start of frame (SOF) signals from a port, such as a USB port. For a selected number of SOF signals received, an actual number of system clock cycles is determined for a time interval corresponding to the selected number of SOF signals. The actual number of system clock cycles is compared to a nominal number of system clock cycles and a sampling interval is adjusted based on the comparison. The actual number of system clock cycles may be determined using a count-and-capture counter. The nominal number of system clock cycles may be calculated based on a nominal system clock rate and on a known SOF interval. Generating sampling intervals may include using a divide-by-N counter.

Abstract: A method of processing force signals from plural force platforms includes, in a computer, in an initialization process, receiving data distinguishing the plural platforms, monitoring force data signals from each of the plural platforms, and identifying each of the plural platforms to a force platform data process application by a sequence of received above-threshold force data signals. The method further includes, subsequent to the initialization process, processing subsequent force data signals according to the identification of each of the plural force platforms. The distinguishing data can include data retrieved from nonvolatile memory of each of the plural force platforms, such as a platform serial number, calibration data, and force platform capacity. A force platform system includes one or more force platforms and force platform signal conditioning circuitry connected to the one or more force platforms.

Abstract: A method for providing feedback during ligament insertion in knee joint orthopedic surgeries includes providing an imaging device providing knee joint articular surface geometry data, providing a position measuring device providing distal ligament insertion sites, providing a strain measuring device providing ligament reference strain, providing a drive system providing a prescribed kinematic path for the knee joint and providing an adaptive migration application. The adaptive migration application receives inputs including the knee joint articular surface geometry data, the distal ligament insertion sites, the ligament reference strain and the prescribed kinematic path for the knee joint and generates outputs including sets of isotonic, hypertonic and hypotonic points representing proximal insertion sites of a ligament fiber associated with prescribed distal ligament insertion sites.

Abstract: The present invention relates to joint simulators, and in particular, to methods and systems for controlling joint simulators by using a haptic mapping technique. A joint simulator is used to closely approximate the conditions within the body, particularly with respect to human and animal joints, and can be used to test and evaluate prosthetics for use in various parts of a human or animal body. The haptic mapping technique improves the rate of convergence of the actual testing forces to the prescribed forces during repetitive performance and life testing. The method is used in conjunction with an impedance-mode servo controller.

Abstract: A system for providing feedback during ligament insertion in knee joint orthopedic surgeries includes an imaging device providing knee joint articular surface geometry data, a position measuring device providing distal ligament insertion sites, a strain measuring device providing ligament reference strain, a drive system providing a prescribed kinematic path for the knee joint and an adaptive migration application. The adaptive migration application receives inputs including the knee joint articular surface geometry data, the distal ligament insertion sites, the ligament reference strain and the prescribed kinematic path for the knee joint and generates outputs including sets of isotonic, hypertonic and hypotonic points representing proximal insertion sites of ligament fiber associated with prescribed distal ligament insertion sites.

Abstract: A method for calibrating a force platform includes, providing a force platform and applying an n×m grid on a top surface of the force platform via a computing device. Next, applying p known loads on each of the n×m grid points of the top surface along a Z-axis being perpendicular to the X and Y axes and along the X and Y axes. Next, taking multipoint measurements at each grid point and for each applied known load along the X, Y and Z axes and generating six measured output signals, exact position coordinates and applied known load magnitude for each grid point. Next, assembling an array of n×m×p of six equations with six unknown for each grid point and applied known load and then solving the assembled equations and deriving a position and load specific calibration matrix for each grid point.

Abstract: A compact multi-axis load cell with opposing rigid mounting elements includes annular flanges at the perimeter of the elements. A sensing region is formed between the rigid mounting elements by bonding, as by welding or brazing, opposing annular flanges at their end surfaces. To increase the mass and rigidity of the opposing mounting elements, the annular flanges may be partially formed by a peripheral groove, the groove defining a portion of an inside surface of the annular flange. The peripheral groove provides sufficient flange length for affixing strain gauges while positioning internal surfaces of the mounting elements close together in order to reduce the overall length of the load cell. Sensing circuits affixed to the outside surface of the sensing region provide output signals responsive to forces and moments exerted between the rigid mounting elements in at least two substantially perpendicular directions.

Abstract: A joint motion simulator to simulate biomechanical motion includes a mount to which a prosthetic device is mounted, actuators coupled to the mount to drive the mount, and a programmable controller to drive the actuators to translate the mount and to rotate the mount with a center of rotation controllable independent of translation. The simulator can include a linear actuator to translate the mount in a linear direction substantially parallel to the axis of rotation. The linear actuator can include a piston within a sleeve, the piston being coupled to the mount and being hydraulically driven to translate the mount, and the actuators can be coupled to the sleeve. The controller may be programmed to vary the center of rotation with linear translation and rotation of the mount. Sensors may be included that measure displacement of the actuators. The controller may drive the actuators based on the measured displacement.

Abstract: A method of processing force signals from plural force platforms includes, in a computer, in an initialization process, receiving data distinguishing the plural platforms, monitoring force data signals from each of the plural platforms, and identifying each of the plural platforms to a force platform data process application by a sequence of received above-threshold force data signals. The method further includes, subsequent to the initialization process, processing subsequent force data signals according to the identification of each of the plural force platforms. The distinguishing data can include data retrieved from nonvolatile memory of each of the plural force platforms, such as a platform serial number, calibration data, and platform capacity. A force platform system includes one or more force platforms and force platform signal conditioning circuitry connected to the one or more force platforms.

Abstract: A simulator for driving a prosthetic element includes a prosthetic drive mechanism that drive the prosthetic element during an accelerated wear test of the prosthetic element. A simulation input represents the action of the simulator and a sensor mechanism is used to measure the force and torque applied to the prosthetic element. Position and orientation control sensors are further used to measure displacement of the prosthetic element. A closed loop feedback control system, responsive to the sensors, is used to determine a drive signal for the drive mechanism. The control system advantageously adds a computational model that incorporates mechanical representations of ligament fibers. The computational model is a non-human approximation to situations that would be encountered by the prosthesis within the human body and includes dimensional geometry of insertion sites and mechanical properties of ligament fibers.

Abstract: A method of processing force signals from plural force platforms includes, in a computer, in an initialization process, receiving data distinguishing the plural platforms, monitoring force data signals from each of the plural platforms, and identifying each of the plural platforms to a force platform data process application by a sequence of received above-threshold force data signals. The method further includes, subsequent to the initialization process, processing subsequent force data signals according to the identification of each of the plural force platforms. The distinguishing data can include data retrieved from nonvolatile memory of each of the plural force platforms, such as a platform serial number, calibration data, and platform capacity. A force platform system includes one or more force platforms and force platform signal conditioning circuitry connected to the one or more force platforms.

Abstract: A simulator for driving a prosthetic element includes a prosthetic drive mechanism that drive the prosthetic element during an accelerated wear test of the prosthetic element. A simulation input represents the action of the simulator and a sensor mechanism is used to measure the force and torque applied to the prosthetic element. Position and orientation control sensors are further used to measure displacement of the prosthetic element. A closed loop feedback control system, responsive to the sensors, is used to determine a drive signal for the drive mechanism. The control system advantageously adds a computational model that incorporates mechanical representations of ligament fibers. The computational model is a non-human approximation to situations that would be encountered by the prosthesis within the human body and includes dimensional geometry of insertion sites and mechanical properties of ligament fibers.

Abstract: A virtual soft tissue control system that provides enhanced motion control to a prosthetic simulator machine. The control system advantageously adds a “virtual soft tissue” control scheme to a conventional control system, such as a digital proportional integral derivative (PID) controller, to algorithmically model the soft tissue constraints that would be encountered by the prosthesis within the human body, and account for these forces in driving the simulator. In another aspect, a prosthetic simulator comprises a prosthetic drive mechanism; a feedback control system that drives the prosthetic drive mechanism; and an iterative learning control system that determines an error from a previous iteration of motion of the drive mechanism and uses the error to determine a drive signal for a subsequent iteration of motion. In certain embodiments, the prosthetic simulator uses both a soft tissue model and an iterative learning control system.

Abstract: A heat exchanger/heater comprising a tubular member having a fluid inlet end, a fluid outlet end and plurality of pins secured to the interior wall of the tube. Various embodiments additionally comprise a blocking member disposed concentrically inside the pins, such as a core plug or a baffle array. Also disclosed is a vapor generator employing an internally pinned tube, and a fluid-heater/heat-exchanger utilizing an outer jacket tube and fluid-side baffle elements, as well as methods for heating a fluid using an internally pinned tube.

Abstract: Corrosion of steel surfaces in a heat pump is inhibited by adding a rare earth metal salt to the heat pump's ammonia/water working fluid. In preferred embodiments, the rare earth metal salt includes cerium, and the steel surfaces are cerated to enhance the corrosion-inhibiting effects.

Abstract: A heat exchanger/heater comprising a tubular member having a fluid inlet end, a fluid outlet end and plurality of pins secured to the interior wall of the tube. Various embodiments additionally comprise a blocking member disposed concentrically inside the pins, such as a core plug or a baffle array. Also disclosed is a vapor generator employing an internally pinned tube, and a fluid-heater/heat-exchanger utilizing an outer jacket tube and fluid-side baffle elements, as well as methods for heating a fluid using an internally pinned tube.

Abstract: An apparatus and method for a multi-axis wheel transducer are disclosed. The apparatus of the invention comprises a wheel transducer for measuring the loads and moments acting on a vehicle wheel. Tubular load cells positioned in a radial fashion around the perimeter of the transducer hub join the rim and hub. Loads and moments acting on the rim of the wheel are transferred through the spoke-like load cells to the hub of the wheel. Sensors strategically positioned around the circumference of the tubular load cell monitor the intensity of the loads and moments. To detect angular position of the wheel, a light source generates a cone of polarized light to flood the wheel of the vehicle and detector-polarizing filter pairs detect an angle of the polarization relative to the wheel to determine its angular position. The transducer hub computer processes the sensor data and transfers the information via infrared signal to a computer located in the fender of the vehicle.

Abstract: A system and apparatus for filling a plurality of vials, and for securing respective caps on each vial securely mounting a plurality of caps on, and filing with a substance, a plurality of vials. A guidance apparatus is provided that has a guide member with a T-shaped track mounted thereon and an traverse carriage having a T-shaped channel formed therein. The traverse carriage further includes two opposingly spaced and offset apertures for receiving the substance therethrough. The two opposingly spaced and offset apertures are each in axial alignment with one of the plurality of vials at the set points as the traverse carriage is slid along the guide member for filing two of the plurality of vials at each of the set points with the substance. A capping apparatus is also included that has two opposingly spaced side walls, and a track mounted between the base and side walls for slidably receiving the plurality of vials.

Abstract: A multi-axis force platform for determining forces and moments exerted on the platform along x, y and z axes includes at least one multi-axis spring. The multi-axis spring includes a block of rigid material through which a pattern of slots pass through to form a series of deflectable beams separated from each other by the slots. The deflectable beams surround an interior region of the spring and elastically couple the interior region of the spring to an outer region of the spring such that the interior region can deflect relative to the outer region along x, y and z axes when subjected to a load. One or more magnetic sensors are positioned within the interior region of the spring for sensing loads exerted on the spring.

Abstract: An engine-driven heat pump system is disclosed in which the waste heat from the engine is used to only heat the water contained in a water heater. Space heating may be then provided by circulating the water through an air-handling unit. In order to simplify the operation, the engine's coolant is circulated through a tube surrounding the heater's storage tank. Any risk of contamination to the potable water supply is removed by venting the region surrounding the coolant-to-water heat exchanger. This is achieved by assuring that a surrounding insulation layer does not form a seal over the heat exchanger and by using a non-setting thermally conductive paste between the tube and tank.