Step motor control for accommodating friction load variation
AssigneeSeiberco Incorporated
InventorAlbert C. Leenhouts
Life of this patent
Estimating the term…
Abstract
Gradually increasing and decreasing the friction torque feedforward term in time, prior to and immediately following intended motion, respectively, reduces the effects of variations in Coulomb friction load in an open loop step motor system.
Claims7
A method for driving an open loop step motor, so as to efficiently accommodate variations in the friction load torque of a system including the motor, comprising generating a multiplicity of step sequences for driving the motor, each of said step sequences being characterized as having a torque feedforward ramp-up component that increases gradually from zero, at a time just prior to commencement of intended movement of the motor armature, to a value, at the instant of intended initial armature movement, just sufficient to overcome the nominal friction load torque of the system.
A system comprising a step motor and a controller for driving said motor in open loop mode so as to efficiently accommodate variations in the friction load torque of said system, said controller comprising electronic data processing means for generating a multiplicity of step sequences for driving said motor, said electronic data processing means being so programmed that each of said step sequences generated thereby is characterized as having a torque feedforward ramp-up component that increases gradually from zero, at a time just prior to commencement of intended movement of the motor armature, to a value, at the instant of intended initial armature movement, just sufficient to overcome the nominal friction load torque of said system.
Dependencies are inferred from the claim text.