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Guaranteeing Isochronous Control of Networked Motion Control Systems Using Phase Offset Adjustment.

Kim I, Kim T - Sensors (Basel) (2015)

Bottom Line: In realizing the idea, we performed a pre-runtime analysis to determine a safe and reliable phase offset and applied the phase offset to the runtime code of motion controller by customizing an open-source based integrated development environment (IDE).We also constructed an EtherCAT-based motion control system testbed and performed extensive experiments on the testbed to verify the effectiveness of our approach.The experimental results show that our heuristic is highly effective even for low-end embedded controller implemented in open-source software components under various configurations of control period and the number of motor drives.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Information Engineering, University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 130-743, Korea. ihkim@uos.ac.kr.

ABSTRACT
Guaranteeing isochronous transfer of control commands is an essential function for networked motion control systems. The adoption of real-time Ethernet (RTE) technologies may be profitable in guaranteeing deterministic transfer of control messages. However, unpredictable behavior of software in the motion controller often results in unexpectedly large deviation in control message transmission intervals, and thus leads to imprecise motion. This paper presents a simple and efficient heuristic to guarantee the end-to-end isochronous control with very small jitter. The key idea of our approach is to adjust the phase offset of control message transmission time in the motion controller by investigating the behavior of motion control task. In realizing the idea, we performed a pre-runtime analysis to determine a safe and reliable phase offset and applied the phase offset to the runtime code of motion controller by customizing an open-source based integrated development environment (IDE). We also constructed an EtherCAT-based motion control system testbed and performed extensive experiments on the testbed to verify the effectiveness of our approach. The experimental results show that our heuristic is highly effective even for low-end embedded controller implemented in open-source software components under various configurations of control period and the number of motor drives.

No MeSH data available.


Related in: MedlinePlus

The CDF distribution of start time of publish phase in the Tcycle. (a) N = 8, Tcycle: 1000μs; (b) N = 8, Tcycle: 500μs.
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f8-sensors-15-13945: The CDF distribution of start time of publish phase in the Tcycle. (a) N = 8, Tcycle: 1000μs; (b) N = 8, Tcycle: 500μs.

Mentions: Figure 8 illustrates the cumulative distribution function (CDF) of measured values. As mentioned earlier, the sum of Ji and determine and the absolute difference Δ of Ji and primarily contributes to the deviation of . This characteristic is more apparent for embedded SBC as shown in Figure 8. In summary, we expect from the pre-runtime analysis results that our heuristic will be more beneficial to low-end embedded SBC with highly fluctuating message release interval.


Guaranteeing Isochronous Control of Networked Motion Control Systems Using Phase Offset Adjustment.

Kim I, Kim T - Sensors (Basel) (2015)

The CDF distribution of start time of publish phase in the Tcycle. (a) N = 8, Tcycle: 1000μs; (b) N = 8, Tcycle: 500μs.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4507583&req=5

f8-sensors-15-13945: The CDF distribution of start time of publish phase in the Tcycle. (a) N = 8, Tcycle: 1000μs; (b) N = 8, Tcycle: 500μs.
Mentions: Figure 8 illustrates the cumulative distribution function (CDF) of measured values. As mentioned earlier, the sum of Ji and determine and the absolute difference Δ of Ji and primarily contributes to the deviation of . This characteristic is more apparent for embedded SBC as shown in Figure 8. In summary, we expect from the pre-runtime analysis results that our heuristic will be more beneficial to low-end embedded SBC with highly fluctuating message release interval.

Bottom Line: In realizing the idea, we performed a pre-runtime analysis to determine a safe and reliable phase offset and applied the phase offset to the runtime code of motion controller by customizing an open-source based integrated development environment (IDE).We also constructed an EtherCAT-based motion control system testbed and performed extensive experiments on the testbed to verify the effectiveness of our approach.The experimental results show that our heuristic is highly effective even for low-end embedded controller implemented in open-source software components under various configurations of control period and the number of motor drives.

View Article: PubMed Central - PubMed

Affiliation: Department of Mechanical and Information Engineering, University of Seoul, 163 Seoulsiripdae-ro, Dongdaemun-gu, Seoul 130-743, Korea. ihkim@uos.ac.kr.

ABSTRACT
Guaranteeing isochronous transfer of control commands is an essential function for networked motion control systems. The adoption of real-time Ethernet (RTE) technologies may be profitable in guaranteeing deterministic transfer of control messages. However, unpredictable behavior of software in the motion controller often results in unexpectedly large deviation in control message transmission intervals, and thus leads to imprecise motion. This paper presents a simple and efficient heuristic to guarantee the end-to-end isochronous control with very small jitter. The key idea of our approach is to adjust the phase offset of control message transmission time in the motion controller by investigating the behavior of motion control task. In realizing the idea, we performed a pre-runtime analysis to determine a safe and reliable phase offset and applied the phase offset to the runtime code of motion controller by customizing an open-source based integrated development environment (IDE). We also constructed an EtherCAT-based motion control system testbed and performed extensive experiments on the testbed to verify the effectiveness of our approach. The experimental results show that our heuristic is highly effective even for low-end embedded controller implemented in open-source software components under various configurations of control period and the number of motor drives.

No MeSH data available.


Related in: MedlinePlus