On the eve of Labor Day, inside the bustling workshop of CRRC Tangshan Co., Ltd., Chang Jiabao was seen inspecting polishing tools. Together with his colleagues, he spent a year innovating and developing an automatic polishing robot for high-speed train sidewall windows. This invention has transformed the industry's manual polishing methods and has been successfully applied in the production of Harmony and Fuxing intelligent bullet train models. This year, the 27-year-old Chang was honored with the National May Day Labor Medal.
Surprisingly, Chang’s academic background was in mechatronics technology, not directly related to intelligent robotics. Driven by a strong interest in smart robots, he taught himself robot programming and operation, eventually winning first prize in the student category of the Second National Intelligent Manufacturing Application Skills Competition.
Previously, polishing high-speed train windows relied entirely on manual labor. At the CRRC Tangshan workshop, there was once a team of female workers nicknamed the "Seven Polishing Fairies." "A single sidewall has nine windows, including station information windows and large cabin windows. It took seven people five hours to complete the polishing, requiring prolonged bending and straining, making it highly labor-intensive," Chang explained. To improve efficiency and reduce physical strain on workers, they embarked on developing an automatic window polishing robot.
The first major challenge in the development was equipping the robotic arm with suitable polishing tools. Chang demonstrated a polishing wheel slightly larger than the window, noting, "Perfect size matching doesn’t necessarily yield the best polishing results." During testing, he found that smaller wheels wore out before completing a single polishing path. "Windows have straight edges and curved corners; different points require different polishing wheels. The polishing directly affects subsequent glass installation—if it's too small, the glass won’t fit; if it's too large, it compromises window sealing," Chang said. It took over a hundred tests just to match the appropriate wheels to different positions, finally equipping the robot with effective tools.
"Unlike humans, the robot can’t move around the sidewall to polish from various angles," Chang noted. Initially, the robot couldn’t even accurately locate the polishing points, resulting in poor efficiency. To enable quick and precise positioning, Chang implemented laser scanning technology. "The laser scans the window’s position and sends the data to the robot, effectively giving it ‘eyes’ to identify where each window is located on the sidewall," he explained.
Even with "eyes," the robot was still like an apprentice in Chang’s view: "The eyes understood, but the hands hadn’t caught up. A single window’s polishing program contains hundreds of paths, detailing the polishing position, the robotic arm’s posture, and speed." Essentially, deciding whether to polish straight lines or corners first posed a challenge for the robotic "trainee." Chang adopted a meticulous approach: each time polishing parameters were adjusted, a test run was conducted. From thousands of parameter sets, the optimal solutions were "fed" into the program to ensure consistent and complete polishing across all sidewall windows.
After more than a year of testing and adjustments starting in 2019, the automatic polishing robot developed by Chang and his team was successfully implemented. "Now, only two workers are needed to operate the robot, completing the window polishing in just two and a half hours," Chang stated. The former "Seven Polishing Fairies" have since transitioned to digital roles.
Currently, Chang and his colleagues continue to refine and update the automatic polishing robot, with plans to adapt it for more vehicle types, including metro trains. "Innovation isn’t inherently difficult; it lies in breaking through routine problems step by step," Chang remarked. It is his patience and dedication to research that enabled this vocational school graduate to earn a "ticket" to national recognition, polishing innovation into a badge of honor for his youth.
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