The SPRR/S Manipulator (PCT PATENT)

With respect to active exoskeleton applications, an estimated 20,639,200 (7.1%) of non-institutionalized United States residents suffered from an ambulatory disability in 2013, while an approximated 2,512,800 (7.2%) of Canadians reported mobility disablements in 2012. These disabilities cost an estimated annual equivalent of $375 billion in family caregiver support, in addition to significant economic and social burdens to the patient and the healthcare system. 

One emergent technology that aims to diminish this health problem and improve the quality of life for sufferers is the lower-body exoskeleton: wearable robotic systems that completely or partially support their user’s weight and provide controlled guidance of leg movements, thereby allowing their user to stand and walk. This solution provides benefits over wheelchair use and other traditional means because it can also help reduce secondary complications of immobility such as pneumonia, blood clots, pressure sores, and lowered self-esteem. However, one major shortcoming of current exoskeleton technologies is a limited range of motion about the hip and ankle joints, which are both capable of three rotational degrees-of-freedom (DOFs) in the human body. In general, current technologies actively guide one degree-of-freedom hip-centered movements with absent or only passive compliance for one or both of the other DOFs. This design scheme generally results in a serial joint structure within the exoskeleton device, which has an inherently lower payload-to-weight ratio than a parallel structure counterpart. Therefore, this characteristic leads to bulkier than necessary devices.

Furthermore, the instability that arises from a lack of complete kinematic compliance to human joint capabilities often requires attendant use of walking sticks to maintain bodily balance while standing or moving. So, in order to safely operate the exoskeleton system, a user must coordinate motions with additional equipment using their upper body. The inconvenience and effort associated with this requirement causes fewer potential users from adopting the technology and altogether prevents other people from operating the devices who could otherwise benefit from the technology if not for this requirement. 

A motion transfer and target interfacing system that is mechanically capable of providing decoupled or combined 3-DOF rotational motion or inaction to a passive target system is designed. The target system may be any structure containing a 3-DOF rotational joint (e.g. ball-and-socket joint) or a quasi-3-DOF rotational joint (e.g. hip joint). The motion-generation system conveys mechanical action to the target system via a motion transfer and target interfacing system, which physically supports the target system in some extent and converts action from the motion-generation system to desired movements of the target system about its true or quasi 3-DOF rotational joint. The system further comprises motion-generation controller system and motion detection and feedback system. The motion-generation controller system can comprise at least one of an Electromyography (EMG), Electroencephalography (EEG), Joystick, Microcontroller, Actuator driver unit, Power supply unit, Predefined signal, etc. 

The SRRP/S Manipulator (PCT PATENT)

With respect to exoskeleton applications and in general, one major shortcoming associated with robotic orientation guidance
mechanisms for spherical joints is their lack of complete and active kinematic compliance with the targeted joint. In terms of hip exoskeleton applications, this limitation restricts the range of hip-joint motions for which mechanism offers guidance to an orientation space less extensive than normal human capabilities. Based on current literature in the field of wearable robotics and exoskeletons, the majority of exoskeletons associated with ball-and-socket joints do not provide compliance with all three DOFs; furthermore, those designs that support 3-DOF motions do  not provide active guidance to each of them. A further symptom of reducing the DOF capability of an exoskeleton is the serial design of active joint connections. Consequentially, most present-day exoskeletons are composed of kinematic open chains: single-DOF rotary or prismatic joints serially-connected by structural linkages. However, researchers have conclude that closed-chain designs, characterized by at least two active joints connected in parallel with each other, have superior performance than their serial manipulator counterparts in terms of positioning accuracy, speed, force application, and payload-to-weight ratio. In order to overcome these shortcomings, we propose a robotic mechanism that combines a spherical parallel manipulator, providing 3-DOF rotational motion generation about one point in space, and a passive mechanism that non-intrusively transmits the spherical motion to a target ball-and-socket joint located at another point in space. Specifically, the device focuses on hip exoskeleton application and employs the Agile Eye.

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