Abstract: An adaptive semi-automatic sewing system (10) comprises a sewing machine (12), a drive unit (42) including a variable speed motor and encoder for counting stitches sewn and for sensing the rotation of the motor, at least one material edge sensor (40a) mounted ahead of the needle (22) of the sewing machine, and a microprocessor controller (51) coupled to the sewing machine controls. Accurate control of seam lengths and end points is achieved by initiating countdown of a variable number of final stitches responsive to detection of the material edge by the sensors (40a). The system includes controls (98) coupled to microprocessor controller (51) for dynamically adjusting the sensitivity of the sensors (40a) for variances in the materials being sewn.

Abstract: An adaptive semi-automatic sewing system (10) comprises a sewing machine (12), a drive unit (42) including a variable speed motor and encoder for counting stitches sewn and for sensing the rotation of the motor, at least one material edge sensor (40) mounted ahead of the needle (22) of the sewing machine, and a microprocessor controller (51) coupled to the sewing machine controls. Accurate control of seam lengths and end points is achieved by initiating countdown of a variable number of final stitches responsive to detection of the material edge of the sensors (40). The speed of the sewing machine at the time the material edge is detected is monitored and compared to a reference speed. The number of final stitches is then dynamically adjusted to compensate for the speed variance from the reference speed.

Abstract: An adaptive semi-automatic sewing system (10) comprises a sewing machine (12), a drive unit (42) including a variable speed direct drive motor and encoder for counting stitches sewn and for sensing the rotation of the motor, at least one material edge sensor (40) mounted ahead of the needle (22) of the sewing machine, and a microprocessor controller (51) coupled to the sewing machine controls. Accurate control of seam lengths and end points is achieved by initiating countdown of a variable number of final stitches responsive to detection of the material edge by the sensors (40). The amount of stitch completion at the time of detection of the material edge is monitored and a stitch length variance mechanism (17) is actuated at a selected angle of motor rotation taking into account the time delay of the stitch length variance mechanism and the feed characteristics of sewing machine (12) to precisely control the length of the last stitch sewn to improve the accuracy of the seam end point.

Abstract: A method and apparatus for automatically positioning a reciprocating needle while rotating the motor a minimum number of degrees. Apparatus is provided for sensing the motor angle and comparing it with a preset braking angle. After the braking angle has been reached, the motor is decelerated until it reaches a needle positioning speed, whereupon the motor angle is again sensed and compared to the needle positioning angle. The motor rotates until the needle positioning angle has been reached, whereupon the brake is reapplied to stop the motor at the desired needle position in a minimum time duration without performing an additional stitch.