Inclusion Criteria:

• Presence of upper-limb motor dysfunction, with or without concurrent lower-limb impairment, due to one of the following conditions: (a) Stroke, with onset between 2 and 24 months prior to enrollment; (b) Incomplete spinal cord injury (ASIA Scale B, C, or D); (c) Traumatic brain injury; or (d) Orthopedic disorders affecting upper and/or lower limb motor function
• Age between 18 and 60 years
• Ability to understand study procedures and follow instructions, and to provide written informed consent (or assent with guardian consent where applicable)
• Body weight and limb anthropometry compatible with ZEPU-AI2, AI4, AI6 Plus, and AI7A systems, as per manufacturer specifications
• Medically stable and cleared by a physician for robotic rehabilitation, with no active infection, uncontrolled cardiac or respiratory disease, severe osteoporosis, uncontrolled epilepsy, or untreated deep vein thrombosis

Exclusion Criteria:

• Complete spinal cord injury or profound motor paralysis preventing safe interaction with robotic devices
• Severe cognitive impairment, defined as a Mini-Mental State Examination (MMSE) score < 24, that would compromise safe participation
• Severe spasticity of the upper limb, defined as a Modified Ashworth Scale score > 3
• Unstable fractures, severe fixed joint contractures of the shoulder, elbow, wrist, or hand (e.g., > 30°), or severe pain limiting safe robotic training
• Uncontrolled cardiac arrhythmia, presence of a pacemaker, or other implanted electronic medical devices incompatible with robotic sensors
• Pregnancy