A novel forward-dynamics analysis and control of a Human-Robot system wearing a powered prosthetic device in a virtual environment

• Introduces the Smart-Powered Prosthetic Ankle (SPPA) with hybrid motor–spring–damper design. • Integrates OpenSim musculoskeletal model and Simulink controller in hardware-in-the-loop. • Predicts prosthetic ankle torque and kinematics from actuator–controller interaction. • Provides reproducible framework for powered prosthesis design, tuning, and validation. Transtibial amputees often face gait asymmetries because conventional prosthetic ankles lack powered push-off. Passive and energy-storing feet cannot adapt to terrain or provide net-positive work, leading to inefficient walking and secondary musculoskeletal complications. To address these limitations, we present a Smart-Powered Prosthetic Ankle (SPPA) that integrates a brushless DC motor, series springs, and a magnetorheological (MR) damper. A complete forward-dynamics musculoskeletal model of an amputee wearing the SPPA was developed in OpenSim and coupled in real time with a MATLAB/Simulink S-function controller, enabling closed-loop simulation and hardware-in-the-loop testing. The SPPA prototype was fabricated and experimentally tested on a transtibial amputee subject in a gait laboratory. Results demonstrate that SPPA enhances ankle range of motion and joint moment profiles, closely reproducing healthy gait kinematics compared to passive conditions. The MR damper provides adaptive shock absorption at heel strike, while motor-driven plantarflexion restores push-off power. Simulation and experimental outcomes showed strong agreement, validating the integrated framework. Although based on a single-subject trial, this work illustrates how forward-dynamics modeling and hardware testing can be combined to accelerate prosthesis design. Compared to existing OpenSim–Simulink integrations, our framework uniquely closes the loop with a physical device, offering a pathway to reproducible, customizable prosthesis development.