The Electronic Cam Realizes The Research On The Forming Motion Of The Multi-bar Warp Knitting Machine

Planar multi-link or rod-cam are used to existing multi-bar warp knitting machine,longer kinematic chain leads to a large accumulation error,kind of multi-bar warp knitting machine requires a conjugate cam,the machine is poorly adaptable to the woven fabric,in view of these problems,the paper studies the structure scheme of driving the actuators by E-cams,and explores the technical feasibility from theoretical and experimental aspects.This paper analyzes the weaving process of the multi-bar warp knitting machine,which are divided into seven steps: clearing,underlap,overlap,cover,land,knock-over and looping.Based on this,select 15 key points of the groove pin hook in a period of track,and the 16 key positions of tongue tip,and analysis the motion required of needle bed,groove pin and tongues.The structure of groove needle mechanism and tongues mechanism are determinated,and the inverse solution of the actuator is deduced,especially,the specific inverse value in key points and key positions.Use least square method,polynomial fitting is performed on the inverse solution of the groove needle and the tongues mechanisms.Further,five,six and seven polynomial in the inverse value were selected for the motion of needle bed,groove pin and tongue.Deduced positive solutions actuator,calculated when the fitting function is active input,the relative displacement between the grooves pin hook point trajectory and the grooves of the tongues tip with the style tip,as positive solution value,comparing deviation between positive solutions value and heoretical values in key points and key positions.Analyze the working principle and the concrete realization method of the E-cam,write the E-cam control program,lay the fitting actuator in the E-cam parameter,so that the E-cam drives the actuator movement according to the predetermined movement rule.A test system for loop motion device was Established,it mainly consists of mechanical transmission and control system,using a high-speed camera to capture the actual trajectory of the groove pin and compare with the required key position trajectory,the result is as follows: the actual trajectory of the high-speed camera is compared in the theoretical trajectory,in front and rear direction the difference between the measured and predicted critical points in piezo jacquard guide bar and land guide bar regions are 0.1mm,within ±0.25 mm range.The variation in pattern guide bar tip back lapping is 0 in the front and rear direction,within the allowable deviation of ±0.25 mm,while seaming pattern guide bar tip front lapping renders variation below is 0,within the allowable deviation of 1.95 mm.In the up and down direction,all the differences are 0.1mm,within ±0.25 mm range.