Counter-balancing mechanism for improving independence when using an exoskeleton

Abstract

An exoskeleton is a robotic device used in assisting paraplegics with standing and walking. Existing designs use a series of DC motors and brakes to move the different parts of the device. Some exoskeletons mimic the musculoskeletal system by sending signals to a computer that tells the motors to rotate the knee, ankle, and hip joints appropriately for correct forward movement of the device. Users of the devices have a walker or crutches with controls to aid in balance. The goal of this project is to provide complete independence by removing the need for these walking aids. A new leg orthotic has been designed that may be implemented on any exoskeleton device to maintain balance in the fore-aft direction. A series of fast-acting electric actuators respond to the individual's movements. If at any point the device begins to tip, the actuators engage in such a way that the user's leg is brought back to an up-right position allowing balance to be recovered. As this movement takes place, the normal actions of the device's DC motors and brakes are also engaged to avoid falling (the reactions from the motors and brakes are already a feature of current exoskeleton designs.) This is a counter-balancing mechanism and could provide more independence to paraplegics in the future.