Large-Stroke Control of a Telescopic Two-Stage Linear Motor
In this paper, a novel two-stage large-stroke proportional linear motor for fluid power valve technology is developed. It is found that the linear effective stroke is around 10 mm and the maximal output force reaches 15 N for the maximal excitation current of 1.0 A. In the design of the larger 2nd-stage linear motor, the hollow stator with embedded coil and permanent magnet covers and incorporates the smaller 1st-stage linear motor. It is also observed that both the stator and the armature of the 1st-stage linear motor are independently movable and form translational two-dimensional motion. Experiments further prove that such a two-stage large-stroke proportional linear motor can produce diverse modes of motion output even though the motions of the two armatures in the two-stage large-stroke proportional linear motor are translational rather than rotational. It is worth mentioning that the output force/stroke characteristic of the larger 2nd-stage linear motor is actually more nonlinear. However, such a non-linearity is not of great importance since the final precision linear force output control and the precision plunger position control are both accomplished by the armature of smaller 1st-stage linear motor. Finally, in this paper only open loop control scheme is required for the precision large-stroke plunger position control. In addition, the electro-magnetic software FLUX 2D is used as a tool to accomplish the design task and analysis of the two-stage linear motor.
KeywordsLinear motor Hydraulics and pneumatics Proportional technique Fluid power Flux2D
The financial supports of the National Science Council under grant number NSC 100-2221-E-224-022-MY2 is greatly appreciated.
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