Using robotics to improve brain assessments
Clinicians have always had to rely on a patient’s behaviour and movement to diagnose a brain injury or track the impact of neurological diseases. Today, with advanced technology, clinician-scientists have a more precise window on brain function and they are driving new approaches to managing brain injuries and disease.
BKIN Technologies is transforming the assessment of brain-injuries by putting robotic technology in the hands of neuroscientists and clinician scientists around the world. KINARM Labs were invented by Dr. Stephen Scott, a professor in the Department of Biomedical and Molecular Sciences and the Centre for Neuroscience Studies at Queen’s University in Canada. Over 15 years ago, he assembled a team of physicists, neuroscientists and machinists to design a robotic exoskeleton that could precisely move and monitor a person’s arm. Because of his understanding of the brain circuits involved in making healthy arm movements, he was able to create a proprietary suite of tests that allows him to provide a complete brain function assessment in a short period of time.
“It enables researchers to create a ‘fingerprint’, if you will, of the patient’s unique neurological condition. Traditional testing methods, such as touching a finger to the nose or bouncing a ball, just don’t capture the complexity of brain processes necessary for everyday activities such as preparing dinner or driving a car,” says Scott.
One of the major challenges facing Dr. Scott and his research and development team at Queen’s University was the complexity of the robotic system itself. A person either sits in a chair with robotic arms affixed (KINARM Exoskeleton Lab) or grasps on to two robotic manipulandums (KINARM End-Point Lab). The robotics are combined with an augmented reality system which creates a virtual environment where subjects perform tasks, such as directing a hand to a target, or interacting with an object in the environment. A robotic exoskeleton used to analyze human limb kinematics must not only be precise in every minute detail, but also allow a person in the lab to perform active, real-world actions.
The key component that enables smooth, natural, non-jerky robotic movement is the slotless motor. This motor powers and drives the robot through a pulley and belt mechanism. The connection between the motor and the master pulley is therefore critical, requiring zero backlash and no slippage. The initial KINARM Lab design used a pulley that attached to the motor shaft using set-screws. However, the constant changing of motor direction during operation produces high shock loads on this motor-pulley connection, which in the prototype KINARM Labs caused the set screws in the pulley to loosen, resulting in backlash, shaft damage and eventual system failure. A viable coupling solution had to be found.
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