Title
Control Design and Implementation for Sawyer Motors Used in Manufacturing Systems
Abstract
In this paper, hardware integration and control design for a dual-axis linear stepper (Sawyer) motor are addressed. In particular, the Sawyer motor used in the Yaskawa/MotoMan manufacturing system which is utilized in various applications such as assembly, packaging, sorting, and probing, is considered. These motors are equipped with four optical sensors with a position resolution of 0.25 microns. We develop a detailed model of the motor for control validation and provide a comparison of two control designs, namely, a PD (or PID) and a robust adaptive nonlinear controller. To achieve high performance, a number of practical issues (such as delay/latency, finite sampling time, sensor noise, commutation rate, etc.) need to be considered. Effects of these factors are outlined and experimentally demonstrated. Both the considered controllers utilize knowledge of motor position and velocity in all axes. Current measurements are not required. Either numerical differentiation or a dynamic observer can be used to construct the velocity signals from the measured position data. The designed nonlinear controller provides practical stabilization of position tracking errors and achieves better overall performance. Adaptations are utilized so that no knowledge of the electromechanical system parameters is required. The proposed nonlinear controller is robust to load torques, friction, cogging forces, and other disturbances satisfying certain bounds. Furthermore, the controller corrects for the unintended yaw and achieves synchrony of the motor and rotor teeth. We have also observed that if the rotational motion is not corrected for, the performance is very poor for both controllers. This is also true in the case of delay/latency and higher rates of commutation.
Year
DOI
Venue
2011
10.1109/TCST.2010.2091506
Control Systems Technology, IEEE Transactions
Keywords
Field
DocType
PD control,adaptive control,differentiation,linear motors,manufacturing systems,nonlinear control systems,observers,optical sensors,robust control,stability,stepping motors,three-term control,PID controller,Sawyer motors,Yaskawa-MotoMan manufacturing system,control design,dual-axis linear stepper motor,dynamic observer,hardware integration,numerical differentiation,optical sensors,position tracking stabilization,robust adaptive nonlinear controller,Adaptive control,Sawyer motor,position control,robustness,stepper
Control theory,Torque,PID controller,Control theory,Control engineering,Rotor (electric),Adaptive control,Robust control,Linear motor,Open-loop controller,Mathematics
Journal
Volume
Issue
ISSN
19
6
1063-6536
ISBN
Citations 
PageRank 
0-7803-9099-7
3
0.56
References 
Authors
8
4
Name
Order
Citations
PageRank
Prashanth Krishnamurthy130.56
Farshad Khorrami215833.15
Tzer Leei Ng330.56
Igor Cherepinsky430.89