本文采用方同余弦矩阵和假想拆杆的方法,按照机构运动的相对同一性的特点,对包括空间四杆曲柄摇杆机构和平面四杆曲柄摇杆机构在内的,并以双自由度空间五杆机构为核心的封闭差动式复合空间机构,导出运动方程式,以GK13-1型三针绷缝体为例,计算并绘出其弯针尖端运动的空间连杆曲线。 In this paper, the method of square cosine and imaginary dismantling are adopted in this paper. According to the relative identity of the movement of the mechanism, including space four-bar crank rocker mechanism and planar four-bar crank rocker mechanism, Five-bar mechanism as the core of the closed differential composite space agency, derived the equation of motion to GK13-1-type three-stitch  seam body as an example, calculate and draw the curve of the curve of the curved needle tip movement.