Case Studies > High Precision Positioning Within Submicron Mechanism

Even With Belt Pulleys, There is No Need for Gain Adjustment,Highly Accurate Positioning

High Precision Positioning Within Submicron Mechanism

Issue: Low-Cost, High-Precision Positioning Without Hassle

For equipment that requires even higher precision, it is necessary to employ fully closed-loop control for the drive source. This is a proposal for a low-cost stepper motor driver that can perform fully closed-loop control.

Challenge:

Need to Eliminate Hunting
Prefer to Keep the Cost Low, Only to Use It for Fine-Tuned Driving
Prefer to Avoid the Hassle of Gain Adjustment

Solution: High-Precision Positioning Using Feedback From the linear encoder

The new CVD Series fully closed-loop control type uses feedback from the linear encoder to configure high-precision positioning. High precision positioning operation is achieved by combining with an external sensor while maintaining the ease of use of a stepper motor.

High Precision Positioning

The difference in the feedback position relative to the command position is compensated by a fully closed-loop control that directly feeds back the position within the mechanism.

Reference Measured Data

Actual measured data of lost motion (Positioning of motor from CW and CCW directions with respect to the target position, and the error with respect to the target position at that time).

Open Loop Control	Fully Closed-Loop Control
0.726 μm	0.014 μm

Feed screw lead 1 mm
linear encoder resolution 0.1 μm
Measured using laser measuring equipment
Measurement error of ±0.2 ppm relative to travel amount

Reference Measured Data of Lost Motion CW and CCW

Fully Closed-Loop Control of Stepper Motors

At the start of positioning, open loop control takes advantage of the high responsiveness of the stepper motor. After the position command is completed, the machine transitions to position compensation via fully closed-loop control using feedback from an external sensor.

CVD Series Fully Closed-Loop Control

The Advantages of Stepper Motors are Retained

Holding the Stop Position without Hunting

When positioning is completed, the motor stops by its own holding force without hunting. It is best suited for applications where vibration at the time of stopping is a problem.

No Need for Gain Adjustment

No need for gain adjustment to match the mechanism as is the case with servo motors. Since positioning operation does not always use encoder feedback, there is no need to adjust belt pulleys, cams, etc. to suit the mechanism and load.

Even With Belt Pulleys, There is No Need for Gain Adjustment,Highly Accurate Positioning

Compatible With External Sensors Appropriate for the Mechanism

Various types of sensors from various companies are supported, and feedback from the sensor type appropriate for the mechanism can be used.

Linear Encoder

Rotary Encoder

Low Cost

Can be provided at a low cost. Drivers with different shapes and connector orientations are available to match the installation method of your driver.
For more details, please Contact Us.

Right-Angle Type With Mounting Plate
Product Name: CVD5BR-KF