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: 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 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 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: 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 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 for calibrating a force platform includes, providing a force platform and applying an nXm grid on a top surface of the force platform via a computing device. Next, applying p known loads on each of the nXm 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 nXmXp 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 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 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: 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: 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: 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.