A joint actuator assembly incudes a motor, a rotating driving member driven by the motor for driving a driven component, and a transmission assembly located between the motor and the rotating driving member that provides speed reduction from the motor to the rotating driving member. The rotating driving member includes a magnetic/electrical coupling comprising a magnetic coupling component configured to magnetically couple with an opposing magnetic coupling of the driven component, and an electrical element configured to provide an electrical connection to an opposing electrical element of the driven component. The actuator and driven component may be combined into a mobility device including a magnetic/electrical coupling system comprising a first magnetic/electrical coupling on the actuator assembly that magnetically and electrically couples to a second magnetic/electrical coupling on the driven component. The magnetic coupling system includes a plurality of magnetic elements located on the first and/or second magnetic/electrical couplings and opposing electrical elements for electrical connection when the actuator assembly and the driven component are joined together.