Control system for providing stitch length control of a sewing machine.

摘要

An adaptive semiautomatic 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. The system (10) has manual, teach and auto modes of operation. In the teach mode, control parameters for each seam are stored as the operator sews the initial piece. 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 edges by the sensors (40). In dependence upon the amount of the stitch which has been sewn upon edge detection, the reverse lever (17) is moved against stop member (13) in order to reduce the length of the last stitch sewn in order to improve the accuracy of the seam end point.