Patent ID: 8585042

Claim:
A pick mechanism comprising: a movable pick component; a stepper motor; and a stepper motor controller; wherein the stepper motor is operably connected to the pick component to drive the pick component in a sequence of movements; wherein each movement involves the pick component travelling in one direction between one position and another position in a required time; wherein the controller produces control signals that control the motor such that the pick component is driven during a movement at or close to the minimum rate of acceleration required to complete the movement in the required time; wherein each movement is divided into an initial phase and a final phase, and control signals are produced such that the pick component is driven with positive acceleration during the initial phase and with negative acceleration during the final phase; and wherein the initial phase is equal to half of the required time with the acceleration rate during the initial phase calculated based on the rate required to complete half the movement in half of the required time and the deceleration during the final phase equal to the negative of the acceleration during the initial phase.