Table 1. Comparison of fault estimation and accommodation methods

Method	Combined faults	Key characteristics / limitations
IMU tracking and torque comparison	✕	Inverse-dynamics contamination under sensor faults
Recurrent NN adaptive observer	△	Sequential faults not analyzed
NN + nonlinear observer	✕	Accelerometer, actuator, and sequential faults not integrated
Proposed	○	Integrated compensation of sequential sensor–actuator faults