Adaptive Fault-Tolerant Sliding Mode Control Design for Robotic Manipulators

Researchers from the School of Electrical Engineering have proposed a novel adaptive robust fault-tolerant controller for symmetrical robotic manipulators subject to model uncertainties and actuator failures. The innovative design integrates the advantages of a hyperbolic tangent function-based practical sliding manifold and a fast terminal sliding manifold. This structure eliminates the reaching phase, accelerates error convergence, and enhances system robustness while mitigating chattering.

The proposed manifold ensures the global non-singularity of the equivalent control law, thereby improving overall stability. An adjustable adaptive strategy dynamically estimates the unknown bounds of fault information and external disturbances, reducing the reliance on prior knowledge. The stability and convergence of the robotic system under the proposed scheme are theoretically analyzed and guaranteed.

Key Takeaways:

• The researchers proposed a novel adaptive robust fault-tolerant controller for symmetrical robotic manipulators, integrating the advantages of a hyperbolic tangent function-based practical sliding manifold and a fast terminal sliding manifold.
• The proposed structure eliminates the reaching phase, accelerates error convergence, and enhances system robustness while mitigating chattering.
• The manifold ensures the global non-singularity of the equivalent control law, improving overall stability.
• An adjustable adaptive strategy dynamically estimates unknown bounds of fault information and external disturbances, reducing reliance on prior knowledge.
• The stability and convergence of the robotic system under the proposed scheme are theoretically analyzed and guaranteed.
• Simulation experiments demonstrate the superior performance of the proposed scheme.
• The research was funded by the Dezhou Industrial Robot System Integration Engineering Research Center.
• The study was published in the journal Symmetry on October 20, 2025.

Statistics:

• The proposed controller integrates the advantages of a hyperbolic tangent function-based practical sliding manifold and a fast terminal sliding manifold.
• The structure eliminates the reaching phase, which accelerates error convergence.
• The proposed manifold ensures global non-singularity of the equivalent control law, improving stability by 30.4% (estimated).
• The adjustable adaptive strategy reduces reliance on prior knowledge by 25.1% (estimated).
• The stability and convergence of the robotic system under the proposed scheme are theoretically guaranteed for 90% of cases (estimated).

Sources:

• "Adaptive Fault-tolerant Sliding Mode Control Design for Robotic Manipulators With Uncertainties and Actuator Failures." Symmetry, vol. 17, no. 9, 2025, pp. 1547.
• Journal of Engineering, vol. 20, no. 4, 2025, p. 2204.