System and method for periodic-electrode-based real-time micro-object position control with the aid of a digital computer

Abstract

The system and method described allow for real-time control over positioning of a micro-object. A movement of at least one micro-object suspended in a medium can be induced by a generation of one or more forces by electrodes proximate to the micro-object. Prior to inducing the movement, a simulation is used to develop a model describing a parameter of an interaction between each of the electrodes and the micro-object. A function describing the forces generated by an electrode and an extent of the movement induced due to the forces is generated using the model. The function is used to design closed loop policy control scheme for moving the micro-object towards a desired position. The position of the micro-object is tracked and taken into account when generating voltage patterns in the scheme.

What is claimed is: 
     
         1 . A system for periodic-electrode-based real-time micro-object position control with an aid of a digital computer, comprising:
 a sensor configured to capture a position of at least one micro-object at a plurality of time points;   at least one processor configured to execute computer-executable code and further configured to:
 obtain one or more parameters of a system for positioning the at least one micro-object, the system comprising at least one control unit comprising a plurality of spatially periodic electrodes, the electrodes configured to induce movements of the at least one micro-object when the at least one micro-object is suspended in a fluid proximate to the electrodes upon a generation of one or more forces by one or more of the electrodes; 
 model a parameter of an interaction between each of the electrodes and the at least one micro-object; 
 obtain a desired position of the at least one micro-object; 
 implement via a plurality of voltage patterns a control scheme for moving the at least one micro-object until the position of the at least one micro-object matches the desired position, implementing each of the voltage patterns comprising:
 determine a voltage to be generated by one of the electrodes in the control unit based on the parameter model, the at least one micro-object's position at a most recent one of the time points, and the desired positon; 
 determine a voltage to be generated by each of the remaining electrodes in the control unit using the voltage for the one electrode and a position of that remaining electrode relative to the one electrode; and 
 command the electrodes to generate the determined voltages, wherein the position of the at least one micro-object is determined after each of the voltage generations. 
 
   
     
     
         2 . A system according to  claim 1 , the at least one processor further configured to solve an optimization problem to obtain the voltage for the one electrode. 
     
     
         3 . A system according to  claim 1 , wherein the control scheme comprises the commands that result in the electrodes implementing the voltage patterns for a predefined length of time, with the implementation of each of the voltage patterns being separated by predefined time intervals. 
     
     
         4 . A system according to  claim 3 , wherein the time points at which the at least the sensor captures the position of the at least one micro-object are separated by regular time intervals. 
     
     
         5 . A system according to  claim 4 , wherein a length of the predefined time intervals separating implementation of the voltage patterns is dependent on the predefined length of time of the implementation and a length of the regular time intervals at which the at least one camera captures the positions of the at least one micro-object. 
     
     
         6 . A system according to  claim 1 , wherein each of the electrodes in the control unit is independently controlled. 
     
     
         7 . A system according to  claim 6 , wherein all of the electrodes in the control unit are controlled simultaneously. 
     
     
         8 . A system according to  claim 1 , wherein a sequence of the electrodes repeats periodically starting from an outside of the control unit and moving towards the center of the control unit. 
     
     
         9 . A system according to  claim 1 , wherein the electrodes are spiral electrodes. 
     
     
         10 . A system according to  claim 1 , wherein the at least one processor is further configured to analyze data provided by the sensor to monitor motion of the at least one micro-object in relation to the control unit. 
     
     
         11 . A method for periodically-repeating-electrode-based real-time micro-object position control with an aid of a digital computer, comprising:
 capturing by a sensor a position of at least one micro-object at a plurality of time points;   obtaining, by at least one processor configured to execute computer-executable, one or more parameters of a system for positioning the at least one micro-object, the system comprising at least one control unit comprising a plurality of electrodes, wherein a sequence of the electrodes repeats periodically starting from an outside of the control unit and moving towards the center of the control unit, the electrodes configured to induce movements of the at least one micro-object when the at least one micro-object is suspended in a fluid proximate to the electrodes upon a generation of one or more forces by one or more of the electrodes;   modeling by the at least one processor a parameter of an interaction between each of the electrodes and the at least one micro-object;   obtaining by the at least one processor a desired position of the at least one micro-object;   implementing by the at least one processor via a plurality of voltage patterns a control scheme for moving the at least one micro-object until the position of the at least one micro-object matches the desired position, implementing each of the voltage patterns comprising:
 determining voltage to be generated by one of the electrodes in the control unit based on the parameter model, the at least one micro-object's position at a most recent one of the time points, and the desired positon; 
 determining a voltage to be generated by each of the remaining electrodes in the control unit using the voltage for the one electrode and a position of that remaining electrode relative to the one electrode; and 
 commanding the electrodes to generate the determined voltages, wherein the position of the at least one micro-object is determined after each of the voltage generations. 
   
     
     
         12 . A method according to  claim 11 , further comprising solving an optimization problem to obtain the voltage for the one electrode. 
     
     
         13 . A method according to  claim 11 , wherein the control scheme comprises the commands that result in the electrodes implementing the voltage patterns for a predefined length of time, with the implementation of each of the voltage patterns being separated by predefined time intervals. 
     
     
         14 . A method according to  claim 13 , wherein the time points at which the at least the sensor captures the position of the at least one micro-object are separated by regular time intervals. 
     
     
         15 . A method according to  claim 14 , wherein a length of the predefined time intervals separating implementation of the voltage patterns is dependent on the predefined length of time of the implementation and a length of the regular time intervals at which the at least one camera captures the positions of the at least one micro-object. 
     
     
         16 . A method according to  claim 11 , wherein each of the electrodes in the control unit is independently controlled. 
     
     
         16 . method according to  claim 16 , wherein all of the electrodes in the control unit are controlled simultaneously. 
     
     
         18 . A method according to  claim 11 , wherein the electrodes are spiral electrodes. 
     
     
         19 . A method according to  claim 11 , wherein the at least one processor is further configured to analyze data provided by the sensor to monitor motion of the at least one micro-object in relation to the control unit. 
     
     
         20 . A system for independently-driven-electrode-based real-time micro-object position control with an aid of a digital computer, comprising:
 a sensor configured to capture a position of at least one micro-object at a plurality of time points;   at least one processor configured to execute computer-executable code and further configured to:
 obtain one or more parameters of a system for positioning the at least one micro-object, the system comprising at least one control unit comprising a plurality of independently driven electrodes, wherein a sequence of the electrodes repeats periodically starting from an outside of the control unit and moving towards the center of the control unit, the electrodes configured to induce movements of the at least one micro-object when the at least one micro-object is suspended in a fluid proximate to the electrodes upon a generation of one or more forces by one or more of the electrodes; 
 model a parameter of an interaction between each of the electrodes and the at least one micro-object; 
 obtain a desired position of the at least one micro-object; 
 implement via a plurality of voltage patterns a control scheme for moving the at least one micro-object until the position of the at least one micro-object matches the desired position, implementing each of the voltage patterns comprising:
 determine a voltage to be generated by one of the electrodes in the control unit based on the parameter model, the at least one micro-object's position at a most recent one of the time points, and the desired positon; 
 determine a voltage to be generated by each of the remaining electrodes in the control unit using the voltage for the one electrode and a position of that remaining electrode relative to the one electrode; and 
 command the electrodes to generate the determined voltages, wherein the position of the at least one micro-object is determined after each of the voltage generations.