Alcon, Inc.

Alcon Research, Ltd.

Daryush Agahi

Jiansheng Zhou

David Williams

Shawn X Gao

T Scott Rowe

David Lloyd Williams

Systems and methods for optimizing the application of pulse width modulation (PWM) in a voltage signal for delivering a current in a valve used to alternatively deliver pressurized gas to and vent from chambers in a vitrectomy probe used to drive a cutter.

Methods of solenoid valve control optimization

A surgical system having feedback control for pneumatic actuators includes a pneumatic pressure source and a vitrectomy cutter having a cutting mechanism, a first pneumatic input port, and a second pneumatic input port. A pneumatic actuator is configured to direct pneumatic pressure to one of the first and second pneumatic input ports. A first pressure transducer is located and configured to detect actual pressure at the first pneumatic input port, and a second pressure transducer is located and configured to detect actual pressure at the second pneumatic input port. A controller communicates with the first and second pressure transducers and the pneumatic actuator. It is configured to change the pneumatic actuator actuation timing based on the data communicated from the first and second pressure transducers.

Feedback control of on/off pneumatic actuators

In some embodiments, a method of using feedforward to control a system component may include determining if a feedforward term exists in a feedforward table for a received operating set point. If a feedforward term does not exist, the system component may be incremented until the system is within a first acceptable tolerance of the desired set point. In some embodiments, a measure of steady state error may be determined and compared to a second acceptable tolerance. If within the acceptable tolerance, the corresponding feedforward term may be recorded in the feedforward table. In some embodiments, if the feedforward term exists for the operating set point, the system component may be controlled using controller output that corresponds to the feedforward term. When a change to the system is detected that is associated with possible changes to the feedforward values, new feedforward values may be generated for the feedforward table.

Systems and methods for dynamic feedforward

A continuous high resolution fluid level monitoring system is provided by embodiments of the present invention. This continuous high resolution fluid level monitoring system includes a unique fluid level sensor having a point light source, parabolic reflector, sensor array, and detection, processing and control system. The point light source illumines a parabolic reflector wherein the point light source is located at the focus of the parabolic reflector. The parabolic reflector reflects light from the point light source to produce a parallel light curtain. This parallel light curtain is parallel to an axis of symmetry of the parabolic reflector. The parallel light curtain illumines a chamber such as a chamber in an ophthalmic surgical device used to contain surgical fluid. The sensor array coupled to the chamber detects the parallel light curtain illuminating the chamber. The sensor array provides an output to a detection/processing/control system in order to determine the fluid level within the chamber. This optical method of determining the surgical fluid levels may be advantageous in that it prevents physical contamination of the surgical fluids.

Growing community of inventors

Irvine, CA, United States of America

Daryush Agahi