A device for guiding and detecting motions of a target joint, the device comprising: - a motion generator having a plurality of actuators, a driver in communication with the plurality of actuators, a moving component and a network of joints and linkages interconnected with the plurality of actuators, a coordinated action of the plurality of actuators and network of joints and linkages of the motion generator generating motion at the moving component with a first center of rotation that does not coincide with a center of rotation of the target joint; - a motion transfer and target interfacing unit connected to the moving component of the motion generator and the target joint, the motion transfer and target interfacing unit comprising at least one rotary joint, at least one linear-motion joint comprising a sliding component and a track component, a mounting means coupling the motion transfer and interfacing unit to the target joint and a network of linkages and joints interconnected together to join the at least one rotary joint and the at least one linear-motion joint, the sliding component interfacing the track component to slide along the track component, the motion transfer and target interfacing unit configured to transfer the motion generated by the motion generator at the moving component to provide a 3-DOF rotational motion at the mounting means with a center of rotation that coincide with a center of rotation of the target joint, while the center of rotation of the moving component of the motion generator does not overlap with the center of rotation of the target joint; and - a controller in communication with the motion generator and the motion transfer and target interfacing unit, the controller comprising an input unit, an output unit and a processing unit, the controller sending output signal to the motion generator to actuate the driver of the at least one actuator. - a motion generator having a plurality of actuators, a driver in communication with the plurality of actuators, a moving component and a network of joints and linkages interconnected with the plurality of actuators, a coordinated action of the plurality of actuators and network of joints and linkages of the motion generator generating motion at the moving component with a first center of rotation that does not coincide with a center of rotation of the target joint; - a motion transfer and target interfacing unit connected to the moving component of the motion generator and the target joint, the motion transfer and target interfacing unit comprising at least one rotary joint, at least one linear-motion joint comprising a sliding component and a track component, a mounting means coupling the motion transfer and interfacing unit to the target joint and a network of linkages and joints interconnected together to join the at least one rotary joint and the at least one linear-motion joint, the sliding component interfacing the track component to slide along the track component, the motion transfer and target interfacing unit configured to transfer the motion generated by the motion generator at the moving component to provide a 3-DOF rotational motion at the mounting means with a center of rotation that coincide with a center of rotation of the target joint, while the center of rotation of the moving component of the motion generator does not overlap with the center of rotation of the target joint; and - a controller in communication with the motion generator and the motion transfer and target interfacing unit, the controller comprising an input unit, an output unit and a processing unit, the controller sending output signal to the motion generator to actuate the driver of the at least one actuator.