Integrating High-Speed Spindle Control in Robotic Machining Systems

Danfoss partnered with the Danish Advanced Manufacturing Research Center (DAMRC) to integrate a high-frequency automation drive into a new robotic machining setup. Through this collaboration, the research institute validates high-speed material removal applications to support wider technology adoption across the industrial manufacturing sector.

Overcoming Structural Resonance in Industrial Robots
DAMRC focuses on applied research to bridge the gap between academic institutions and the manufacturing industry. A core area of investigation is robotic machining, a process that offers spatial flexibility and cost advantages over traditional CNC machines for large or complex components. However, industrial robot arms possess lower structural stiffness, which can induce severe resonance and vibration during material removal at standard operating speeds. To mitigate this mechanical instability, DAMRC required a spindle capable of operating at frequencies up to 900 Hz.

Unifying Speed Regulation and Position Control
Operating a spindle at 900 Hz exceeds standard industrial drive parameters. Furthermore, the application required dual functionality from the drive unit. During active material removal, the system needed continuous speed control to maintain the 900 Hz rotation. Conversely, the system required precise position control at zero or minimal speed to orient and index the spindle accurately during automatic tool changes.

To address these distinct operational requirements, DAMRC selected an iC7-Automation drive equipped with Motion OS701 functionality. This specific architecture allows the system to operate in speed control during active machining and seamlessly switch to position sensing for tool changes, without requiring a complete stop and restart sequence in a different operating mode.




System Integration and Data Monitoring
The deployment process involved electrical design, safety configuration, and PROFINET integration connecting the robot, programmable logic controller (PLC), and the drive. Danfoss provided ongoing engineering support to align the drive parameters with the specific certification and mechanical requirements of the high-speed spindle.

Additionally, the setup incorporates the MyDrive Insight software tool to facilitate real-time monitoring. This software captures drive and process parameters, enabling engineers to analyze system behavior, record operational data, and adjust configurations efficiently as testing variables shift.

De-Risking Advanced Manufacturing Technology
The unified drive architecture provides DAMRC with reliable, granular control over spindle operations across diverse robotic machining setups. By successfully achieving proof-of-concept for this high-frequency application, the research center allows manufacturing companies to test and validate complex material removal processes based on empirical data.

This capability significantly reduces the financial and technical risks associated with scaling unproven robotic machining technology to an industrial level. Building on this successful deployment, the institute is extending the application of this precision control technology to coordinate a rotary positioning table between separate welding and material-removal robots.

Edited by Aishwarya Mambet, Induportals Editor, with AI assistance.

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