Residual jerk reduction in precision positioning stages using sliding microstep-based switching

[摘要] Micro precision X–Y stages have several applications in industry ranging from metal machining to positioning of optical instruments. This paper deals with the evaluation of relationship between jerk in micro precision stages and harmonics in voltage of the motor by which the stage is driven and subsequently proposes an algorithm on Arduino Mega micro controller board to reduce the jerk by shaping the velocity profile while varying the microstepping rate in motor voltage. A micro precision stage with a resolution of 1 micron, driven with a bipolar stepper motor drive is used to evaluate the algorithm. A MEMS accelerometer (ADXL 345) is placed rigidly on the stage, and the acceleration at varying speeds is measured and logged in the micro controller. The micro controller sends commands to the motor driver (L6470 driver) for driving the motor using Serial Peripheral interface. The motor driver is configured in microstepping mode. Experiments confirm the fact that there is a strong correlation between jerk in micropositioning stage and motor supply voltage harmonics. A methodology to reduce the jerk has also been facilitated. This involves use of microstepping mode in stepper motor driver with dynamic sliding in microstepping rate. A threshold value of jerk is considered and based on that, the microstepping rate is varied which subsequently reduces voltage harmonics. Reduction in voltage harmonics reduces the jerk in the stage. Maximum jerk reduction of 97.3 % was achieved in the process...

[学科分类] 自动化工程

[关键词] Residual jerk ;Accelerometer ;Precision stage ;Successive approximation ;Microstepping