Devices and methods for improving accuracy of fluid delivery

An ambulatory infusion pump for delivering therapeutic fluid to a patient's body, the pump including a dispensing unit comprising:

• a reservoir to retain therapeutic fluid;
• a driving mechanism for delivering therapeutic fluid from the reservoir into a patient's body, the driving mechanism including a movable member that moves when therapeutic fluid is being delivered;
• at least one sensor configured to sense a relative position of the movable member, and generating a corresponding sensor signal;
• and
• a processor in electrical communication with the at least one sensor and configured with instructions to control the driving mechanism,
• wherein the processor controls the driving mechanism based on the sensor signal and at least one flow characteristic of the therapeutic fluid being delivered such that a compensation amount of therapeutic fluid is delivered to compensate for a change in the flow of therapeutic fluid occurring ring during operation of the driving mechanism.

A method for delivering therapeutic fluid to a patient's body, the method comprising the steps of:

• operating a driving mechanism to deliver therapeutic fluid to a patient, the driving mechanism including a movable member operatively coupled to a motor;
• receiving a sensor signal corresponding to a relative position of the movable member;
• determining amount of therapeutic fluid based on the sensor signal and on at least one flow characteristic of the therapeutic fluid;
• and
• controlling the driving mechanism to deliver the determined amount of therapeutic fluid to the patient to compensate for a change in the flow of therapeutic fluid occurring during operation of the driving mechanism.