Abstract: In a method for controlling sewing operation of a sewing machine, a stitch needle completes an in-and-out movement on a fabric with a first tension applied to an upper thread when the stitch needle, with respect to a fabric-feeding mechanism, is at a first relative position corresponding to a first pattern part of a predetermined stitch pattern. Afterward, the stitch needle is moved, with respect to the fabric-feeding mechanism, to a second relative position corresponding to a second pattern part of the predetermined stitch pattern, and completes an in-and-out movement on the fabric at the second relative position with a second tension, which is greater than the first tension, applied to the upper thread.

Abstract: In a method for controlling sewing operation of a sewing machine, a stitch needle completes an in-and-out movement on a fabric with a first tension applied to an upper thread when the stitch needle, with respect to a fabric-feeding mechanism, is at a first relative position corresponding to a first pattern part of a predetermined stitch pattern. Afterward, the stitch needle is moved, with respect to the fabric-feeding mechanism, to a second relative position corresponding to a second pattern part of the predetermined stitch pattern, and completes an in-and-out movement on the fabric at the second relative position with a second tension, which is greater than the first tension, applied to the upper thread.

Abstract: A motor control device is used to control an electric motor that drives a presser mechanism of a sewing machine and includes a knee lever mechanism and a control module. The knee lever mechanism includes a switch component, an actuator rotatable to actuate the switch component at a predetermined angular position, and a rotatable knee lever operable by knee contact to rotate and to drive rotation of the actuator. When the control module determines that the switch component is actuated, the control module controls the electric motor to move the presser mechanism to dispose a presser foot of the presser mechanism at a predetermined height relative to a bed of the sewing machine.