Knee exoskeletons are sophisticated wearable devices engineered to aid or augmenthuman movement, especially in rehabilitation and mobility assistance contexts. Toaddress reliability concerns, the proposed knee exoskeleton incorporates a fault-tolerantcontrol system using a fault detection, isolation and reconfiguration (FDI) technique. Thissystem enables the exoskeleton to continue functioning even if one of the actuators experiencesa fault, ensuring user safety and continuous operation. For actuator fault detection,analytical redundancy relations (ARRs) are derived from the bond graph model of the kneeexoskeleton. ARRs are monitored for actuator fault detection and isolation. In this work,there is no fault initially; after some time, a fault is created in the rotary actuator; finally,the faulty actuator is reconfigured by another rotary actuator. Simulation findings illustratethe suggested FDI system’s effectiveness in improving the robustness of knee exoskeletonsduring the sit-to-stand motion. The proposed system successfully reconfigures itself inresponse to faults.