Patent ID: 9038735
Filing Date: 2015-05-26
Classification: E21B

Abstract:
1. An actuator for a downhole tool, comprising: a housing; an actuator, housed in the housing, that generates a force to be applied to a downhole tool that is connectable to the actuator; a shaft, in the housing, that transfers the force of the actuator to the downhole tool that is connectable to the actuator; an electronic control system that provides control signals to the actuator; the electronic control system having a plurality of sensors that detect operation of the actuator and affect the control signals provided to the actuator and sensorless circuitry that detect the operation of the actuator; and wherein the electronic control system detects that a sensor has failed, switches to the sensorless circuitry when the sensor has failed and uses an output signal from the sensorless circuitry and output signals from the plurality of sensors that did not fail to provide the control signals to the actuator so that the actuator operates even when the sensor has failed.