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Gentleflow: A time-synchronized optimization approach for online trajectory generation with gentle torque control for
Shize Zhao1, Tianjiao Zheng1, Chengzhi Wang1
1State Key Laboratory of Robotics and System, School of Mechatronics Engineering, Harbin Institute of Technology, Harbin 150001, China.
ISA Transactions
|September 25, 2025
Summary
Gentleflow, a novel online trajectory generation method, achieves smoother robot arm movements by precisely controlling joint torques and minimizing jerk. This advanced technique enhances robot compliance and repeatability for complex tasks.
Area of Science:
- Robotics
- Control Systems
- Mechatronics
Background:
- Smooth torque control is crucial for multi-joint manipulators.
- Existing methods struggle with precise jerk constraint handling for trajectory synchronization.
Purpose of the Study:
- Introduce Gentleflow, a time-synchronized online trajectory generation (OTG) method.
- Improve trajectory smoothness, compliance, and repeatability in robotic manipulators.
Main Methods:
- Developed a time-synchronized OTG method incorporating explicit jerk constraints.
- Proactively tightened jerk bounds to suppress torque rate variations.
- Validated on a 6-DOF industrial robot with diverse motion tasks.
Main Results:
- Gentleflow significantly reduced end-effector vibrations during high-speed motions.
- Achieved smoother, more compliant, and repeatable trajectories compared to existing methods.
- Demonstrated effectiveness in abrupt target-switching, assembly, and long-distance movements.
Conclusions:
- Gentleflow offers practical advantages for complex robotic tasks requiring precise motion control.
- Jointly minimizing jerk and optimizing motor torque is key for synchronized multi-joint motion.
- The refined jerk treatment in Gentleflow enhances overall robotic system performance.
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