Researchers Develop Universal Robot Motion Controller Using Open Industrial Standards
In a significant advancement for industrial automation, a team of engineers from Wuyi University in southern China has unveiled a new software framework for robot motion control that promises greater flexibility, precision, and interoperability across robotic platforms. The breakthrough, detailed in a recent issue of Modern Manufacturing Engineering, introduces a motion controller architecture built on widely adopted industrial standards, offering manufacturers a scalable and vendor-neutral alternative to proprietary control systems.
At the heart of the innovation is a software design rooted in the PLCopen standard—a globally recognized set of guidelines for industrial automation programming. Unlike traditional robot controllers, which are often closed, expensive, and limited to specific brands or models, this new framework leverages open protocols to deliver a universal solution capable of supporting a wide range of multi-joint industrial robots. The research team, led by Dr. Liang Yanyang from the Intelligent Manufacturing Department at Wuyi University, aimed to address long-standing challenges in the robotics industry: high development costs, poor code portability, and the lack of a unified programming environment.
The modern manufacturing landscape is undergoing rapid transformation. As labor costs rise and demand for precision manufacturing intensifies, industries from automotive to electronics are increasingly turning to robotic automation. However, the adoption of robotics has been hindered by the complexity and inflexibility of control systems. Most commercial robot controllers are tightly coupled with specific hardware, making it difficult to transfer software between platforms or integrate third-party components. This vendor lock-in not only increases costs but also slows down innovation.
Recognizing these limitations, Liang Yanyang and his colleagues—Wu Wei, Yao Chaozhi, and Wang Li—set out to design a motion control system that prioritizes openness, real-time performance, and adaptability. Their solution centers on CODESYS, a programming platform compliant with the IEC 61131-3 international standard for programmable logic controllers (PLCs). By using CODESYS as the development environment, the team ensured compatibility with a broad range of industrial hardware and programming languages.
One of the most compelling aspects of their work is the use of structured text (ST), a high-level programming language within the IEC 61131-3 suite. ST allows for complex algorithmic development while maintaining readability and ease of debugging—qualities essential for industrial applications where reliability is paramount. The team used ST to implement core robotic functions, including forward and inverse kinematics solvers, trajectory interpolation, and multi-axis motion planning.
Kinematics—the mathematical description of motion without considering forces—is fundamental to robot control. Forward kinematics calculates the position and orientation of a robot’s end-effector based on the angles of its joints, while inverse kinematics determines the necessary joint angles to achieve a desired end position. These calculations are computationally intensive and must be executed in real time to ensure smooth and accurate motion.
The Wuyi University team developed efficient algorithms for both forward and inverse kinematics, validated initially in MATLAB before being ported into the CODESYS environment. Their approach was designed to be generalizable, meaning it can be applied not only to six-degree-of-freedom (6-DOF) serial robots—the most common type in industrial settings—but also to specialized robots such as SCARA (Selective Compliance Assembly Robot Arm) and palletizing robots. This universality is a key differentiator from previous efforts, which often targeted a single robot configuration.
Beyond kinematics, the team implemented linear and circular interpolation routines—essential for generating smooth motion paths in three-dimensional space. Interpolation determines how a robot moves between two points, whether along a straight line or an arc. In industrial applications, such as welding, painting, or assembly, precise path control is critical to product quality.
The researchers employed a multi-axis look-ahead trajectory planning algorithm to ensure smooth transitions between motion segments. This technique anticipates upcoming path changes and adjusts velocity profiles accordingly, preventing abrupt accelerations or decelerations that could destabilize the robot or degrade performance. By calculating transition zones and maximum allowable speeds in reverse from the end of a trajectory, then refining them forward, the system maintains dynamic stability while respecting joint limits on speed and acceleration.
A major challenge in motion control is maintaining real-time performance. Delays in command execution can lead to jerky movements, positioning errors, or even system instability. To address this, the team integrated EtherCAT, a high-speed industrial Ethernet protocol, into their architecture. EtherCAT enables deterministic communication with sub-millisecond cycle times, making it ideal for synchronized motion control across multiple axes.
In their experimental setup, the researchers connected a CTH300-series motion controller from Shenzhen-based automation firm COTON to six servo drives, each controlling one joint of a 6-DOF serial robot. Both the controller’s scan cycle and the EtherCAT communication cycle were set to 1 millisecond, ensuring tight synchronization between software commands and hardware response. This level of timing precision is critical for achieving the high control accuracy required in advanced manufacturing.
Another notable feature of the system is its built-in visualization interface, developed using CODESYS’s native visualization tools. This graphical user interface (GUI) allows operators to input trajectory parameters, monitor joint positions in real time, and initiate motion sequences with the click of a button. The interface supports both task-space and joint-space planning, enabling users to define movements either by end-effector coordinates or individual joint angles.
During testing, the team demonstrated the system’s capabilities by executing both linear and circular interpolation tasks. For the linear test, the robot moved from an initial position to a target point defined in Cartesian coordinates. For the circular test, three points—a start, midpoint, and endpoint—were used to define an arc in 3D space. The system successfully calculated the center of the arc and generated a smooth, continuous path.
To evaluate performance, the researchers collected joint position, velocity, and error data during both tests and analyzed them using MATLAB. The results showed that position deviations remained within 0.005 radians across all six joints—a level of precision suitable for most industrial applications. More importantly, the servo motors operated smoothly without oscillation or jitter, indicating effective trajectory planning and control.
The implications of this work extend beyond academic interest. By building on open standards like PLCopen and IEC 61131-3, the Wuyi University team has created a foundation for more modular and interoperable robotics systems. Manufacturers could, in theory, use the same control software across different robot models, reducing training time, simplifying maintenance, and accelerating deployment.
Moreover, the use of standardized programming languages makes it easier for engineers to collaborate, share code, and build upon existing work. This contrasts sharply with proprietary systems, where knowledge is often siloed and customization requires deep expertise in vendor-specific tools.
The research also highlights a growing trend in industrial automation: the convergence of PLC-based control and advanced robotics. Traditionally, PLCs have been used for discrete manufacturing tasks—such as conveyor control or machine sequencing—while robots relied on dedicated controllers. However, as robots become more integrated into production lines, the need for unified control architectures is increasing.
By implementing robot motion control within a PLC-compatible environment, the team has bridged this gap. Their system can seamlessly integrate with existing factory automation infrastructure, enabling tighter coordination between robots, conveyors, sensors, and other equipment. This level of integration is essential for realizing the goals of Industry 4.0, where smart factories rely on interconnected systems to optimize production.
While the current implementation focuses on basic motion functions, the modular design allows for future expansion. Additional features such as collision detection, force control, or machine learning-based optimization could be incorporated into the framework without overhauling the core architecture. This scalability makes the system adaptable to evolving industrial needs.
The team acknowledges that further testing is needed, particularly under load conditions. In real-world applications, robots often handle heavy payloads or operate in dynamic environments, which can affect motion accuracy and stability. Future work will involve subjecting the system to more rigorous mechanical loads and evaluating its performance under varying operational conditions.
Nonetheless, the results published in Modern Manufacturing Engineering represent a meaningful step forward in the democratization of robot control technology. By combining open standards, real-time performance, and user-friendly interfaces, the Wuyi University researchers have created a platform that could lower barriers to entry for smaller manufacturers and startups seeking to adopt robotic automation.
As global competition intensifies and supply chains become more complex, the ability to quickly reconfigure and redeploy robotic systems will be a key competitive advantage. Open, flexible control architectures like the one developed by Liang Yanyang and his team could play a pivotal role in enabling this agility.
The research also underscores China’s growing influence in advanced manufacturing research. While the country has long been a leader in robotics deployment, domestic innovation in core control technologies has lagged behind Western and Japanese counterparts. This project demonstrates that Chinese academic institutions are now making substantive contributions to the foundational layers of industrial automation.
Looking ahead, the principles outlined in this study could inspire similar efforts in other domains, such as mobile robotics, collaborative robots (cobots), or even autonomous vehicles. The emphasis on standardization, modularity, and real-time performance is universally applicable across motion-intensive systems.
In an era where software increasingly defines hardware capabilities, the ability to decouple control logic from physical machinery is transformative. The Wuyi University team’s work exemplifies how open standards can empower innovation, reduce dependency on single vendors, and accelerate technological progress in industrial robotics.
As industries continue to embrace digital transformation, the demand for intelligent, adaptable, and interoperable control systems will only grow. The motion controller framework developed by Liang Yanyang, Wu Wei, Yao Chaozhi, and Wang Li offers a compelling vision of what the future of industrial automation might look like—one where flexibility, precision, and openness are not just aspirations, but engineering realities.
Liang Yanyang, Wu Wei, Yao Chaozhi, Wang Li, Intelligent Manufacturing Department, Wuyi University, Modern Manufacturing Engineering, DOI: 10.16731/j.cnki.1671-3133.2021.12.006