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Application Note, Motion Control Platforms
Application Note

Automation1 Linear Servo Drive Products Provide Industry-Leading In-Position Stability

Aerotech’s Automation1 linear amplifier products provide industry-leading in-position stability performance.

The Automation1 XR3 multi-axis drive rack can be configured with up to six individual XSL3 amplifiers. The Automation1 XL2e enhanced, compact linear servo drive is a single-axis version that uses similar technology. Both the XR3 with XSL3 amplifiers and the XL2e drive use low-noise linear power amplifiers combined with precision servo control technology to provide industry-leading in-position stability.

Each drive was tested by commanding a cross-roller bearing stage to maintain a standstill position using only the drive’s control loops (i.e., no external brake or other device assisted in maintaining position). The stage was horizontally mounted to vacuum rails on a granite table supported by air isolation. The position error was read by the stage’s 4 μm pitch amplified sine-wave encoder, multiplied by each drive’s feedback resolution multiplication circuitry. The root-mean-square (RMS) position measurement was calculated from the collected data. Figure 1 shows the test results for the XSL3 and XL2e, respectively.

Figure 1. Aerotech’s Automation1 XSL3 linear amplifier (top) is controlled by the configured XR3 drive rack. The Automation1 XL2e (bottom) is a fully integrated single-axis drive. Both devices use a 20 kHz servo and current control loop, hardware-based amplified sine-wave encoder resolution multiplication, high-resolution current sensing and excellent signal-processing capabilities, enabling superior positioning performance.

Linear amplifiers have a unique advantage over PWM amplifiers in that they have no switching noise or amplifier deadtime. Therefore, they deliver high-precision position and velocity tracking, making linear amplifiers ideal for small step size and in-position stability applications. Linear amplifiers like the Automation1 XL2e (see Figure 2 below) also have the added benefit of reduced electromagnetic interference (EMI) noise due to the lack of PWM on/off amplifier switching. This feature makes linear amplifiers a desirable choice for many sensing and testing applications.

Figure 2. Aerotech’s Automation1 XL2e, seen here with and without the optional -EB1 expansion I/O board, offers industry-leading performance in a highly integrated design.

Summary

The innovative Automation1 precision machine and motion control platform offers several linear amplifier products. Figure 3 gives a quick summary of testing performed on the XL2e, XL5e and XSL3 linear amplifier products.

Linear amplifierIn-position jitter, cross-roller bearing stageIn-position jitter, air bearing stageDevice typePeak amplifier power dissipation per phase
XSL3 (XR3)0.11 nm, RMS0.6 nm, RMSSlice amplifier for drive rack400 W
XL2e0.12 nm, RMS0.9 nm, RMSSingle-axis drive400 W
XL5e–0.8 nm, RMSSingle-axis drive1200 W
Figure 3. Summary of in-position test results for the Automation1 platform’s XSL3, XL5e and XL2e linear amplifier products. For a complete look at in position stability for Automation1 drive hardware, please refer to this application note.