Patent attributes
An electric power tool is configured to rotate an attachment about a Z-axis. The electric power tool includes a three-axes acceleration sensor and an acceleration detection circuit. The acceleration detection circuit calculates an angular acceleration about the Z-axis based on an input signal from the three-axes acceleration sensor. The acceleration detection circuit calculates a change in an angular velocity based on integrating the angular acceleration for a most recent period. The acceleration detection circuit determines a Z-axis angular velocity about the Z-axis, without adding a previous change in the angular velocity from before the most recent period, as equal to the change in angular velocity. The acceleration detection circuit detects a twisted-motion of the electric power tool based on the Z-axis angular velocity.
