Fastener setting algorithm for drill driver

摘要

An improved technique is presented for detecting when a fastener driven by a drill driver has reaches a desired stopping position. The improved techniques generally includes: sampling periodically current delivered to the electric motor; storing a sequence of current measures most recently sampled; and determining a slope for the sequence of current measures by way of linear regression. Transmission of torque to the output spindle can be interrupted based in part on the slope of the current measures.

主权项

1. A method of controlling operation of a power tool having an electric motor drivably connected to an output spindle to impart rotary motion thereto, comprising:
sampling periodically, by a controller residing in the power tool, current delivered to the electric motor; storing, by the controller, a sequence of current measures sampled by the controller, the sequence of current measures being stored in a memory of the power tool; determining, by the controller, a slope for the sequence of current measures by way of linear regression; and interrupting, by the controller, transmission of torque to the output spindle based in part on the slope of the sequence of current measures.