Methods for deriving and implementing motion profiles for drive systems
AssigneeTektronix, Inc.
InventorEdward F. Burke
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Abstract
The present invention provides a stable, high performance system for driving one or more masses in precise incremental movements. More particularly, the present invention provides a method and system for deriving and implementing motion profiles that govern the movement of one or more masses, such as a printer drum as it is indexed along a rotational path by a stepper motor.
Claims18
A method for generating a motion profile for driving at least one mass in a system between an initial zero velocity location and a desired zero velocity location by a common drive means, the method comprising:
- generating a differential equation of motion for each of said masses in the system;
- expressing the differential equations of motion in a dynamic state variable equation;
- defining an initial and a desired system state and a desired time interval required to advance the system from the initial to the desired state;
- developing a continuous driver input function required to transfer a mass from the initial state to the desired state in the time interval based upon a Kalman controllability formulation;
- and
- implementing the continous driver input function to solve the dynamic state variable equation for a system state vector that describes a continuous position and velocity profile for each mass in the system.
A method for controlling rotational output of a stepper motor rotor in a system wherein the stepper motor rotor is a first mass that drives at least one additional mass between an initial zero velocity location and a desired zero velocity location, comprising:
- generating a differential equation of motion for each of said masses in the system;
- expressing the differential equations of motion as a dynamic state variable equation;
- defining an initial and a desired system state and a time interval required to advance the system from the initial to the desired state;
- developing a continuous driver input function required to transfer a mass from the initial state to the desired state in the time interval based upon a Kalman controllability formulation;
- implementing the continuous driver input function to solve the dynamic state variable equation for a system state vector that describes a continuous position and velocity profile for the stepper motor rotor;
- and
- generating a pattern of stepper motor input pulses and delay times that produces stepper motor rotor output approximating the continuous position profile of the stepper motor rotor described by the system state vector.
In a system comprising a print substrate indexed by rotational output of a stepper motor rotor, the improvement comprising controlling the rotational output of the stepper motor rotor such that its velocity profile during each predetermined time interval between a first zero velocity position and a second zero velocity position is non-linear and substantially non-constant.
In a printing system comprising a print substrate indexed by rotational output of a stepper motor, the improvement comprising controlling the rotational output of the stepper motor rotor to provide a print substrate velocity profile during each predetermined time interval between a first zero velocity position and a second zero velocity position that is non-linear and substantially non-constant.
Dependencies are inferred from the claim text.