Browsing by Author "Costa, Ismael Silva"
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- Test Apparatus for Analysis of Physical Therapy Rehabilitation Algorithms and Motion Sensor AccuracyPublication . Costa, Ismael Silva; Maia, Cláudio Roberto RibeiroThe use of technology to support traditional physical therapy in current times not only is a complement, but also an integral part of different types of rehabilitation. An example of this fusion between technology and physiotherapy is the Digital Physical Therapist developed by SWORD Health. It is used in physiotherapy sessions to provide immediate feedback to the user about the exercise being executed and improve the results of these sessions. SWORD has quality assurance processes in place for testing its products, but none of them physically stimulate the Motion Tracker (MT) repeatedly and accurately. A process like this eliminates circumstantial errors between multiple tests and allows the identification of systematic errors on the MT’s. To solve this problem, we decided to develop a human arm replica that stimulates the MT’s by performing a specific subset of movements. We used two servo motors to replicate the shoulder joint and two more to replicate the elbow joint. These joints are connected using PVC pipes and 3D-printed pieces. The “arm” is attached to a fire extinguisher base. The motors provide feedback signals, which are used to monitor their position. To evaluate the values read by the MT’s, we placed two Inertial Measurement Unit (IMU)’s on the apparatus to track its position. The apparatus is controlled using a MicroController Unit (MCU). This MCU has a shell interface that allows control of the apparatus without needing to change the firmware. This shell supports moving the apparatus and reading values from the IMU’s, among other possible commands. A user interface that connects to the MT’s the user wants to test is also provided, and offers multiple ways of moving the apparatus, such as manually selecting each angle, choosing from a list of presets, or even editing/adding/removing a preset from this list. To test the behavior of this apparatus, functional tests were performed. Four different scenarios were added to test the MT’s: checking if the acceleration module is equal to 1G when the MT’s are resting, identifying if the axes of the MT’s are correctly aligned, checking if the MT’s read the correct acceleration values along all axes, and verifying the quaternions from the MT’s. These tests were performed on a set that included functional and non-functional MT’s. The apparatus proved to be able to identify the defective MT’s in our test group, identifying problems like a wrong acceleration module, axes incorrectly aligned, wrong acceleration values, and wrong quaternions. These results confirmed that the apparatus is capable of being used to automate some of the manual work done by the Quality Assurance team.