Enhanced Prototype Design and Fabrication of a Foot Drop Stimulator Device for Locomotion Control

This proposal deals with the design and fabrication of a stimulator that can control the foot of a patient suffering from foot drop disease provided that the muscles of the foot are undamaged. Knowledge of the motion of selected joints allows calculating appropriate EMG pulses to the legs that stabilizes the patient s gait. These pulses are computed by a microcontroller-based unit, which is part of the proposed design. Instead of patients, the proposed work utilizes a humanoid robot that is capable of imitating the main features of the pathological gait of the patient in question. The controller output is subsequently applied to the joints of the robot to stabilize its locomotion. The first phase of this project relates to the mapping between the patient (human) and the humanoid robot and entails the conversion of recording data from the patient to the motion of the humanoid robot. Once the mapping has been established, the proposed study is conducted on the humanoid robot that, in turn, then andlsquo;suffers from the foot drop disease. The second phase of this project is to fabricate a supporting device for the humanoid robot that stabilizes its locomotion. With the assistance of this devise, the locomotion of the humanoid robot is significantly less affected by the foot drop disease. The controller, that is part of the device, is designed to self-learn the optimal response to minimize the effect of the foot drop disease of the robot. The result of this optimization yields a minimum-energy-gait pattern. It is important to note that the locomotion controller includes a reflex generator module. This module allows compensating effects that arise in the presence of sudden events, for example an unexpected and sudden drop in ground elevation. It is also important to note that the research literature has only sporadically touched upon this issue and no general solution to this problem has been discussed. The project, therefore, aims to solve specific theoretical problems including the control of reflexes and posture-task-reflexes. In addition to that, the fabricated device is developed locally at Sultan Qaboos University and the intellectual property rights are, hence, owned by the Sultanate of Oman. The outcomes of this project are: To develop a low cost technology that responds to the needs of patients having foot drop disease: providing a local technology solution will not only reduce the cost drastically but will also lead to commercializing the product into the Cooperation Council for the Arab States of the Gulf (GCC) and the surrounding region. Besides the insufficiency of the technical measures taken so far by public hospitals to enhance foot drop treatment with high-tech equipment, the question of efficiency in using such devices is also a major issue. In fact, the government is paying an extremely high cost to afford and maintain such medical devices. The potential of having our own technology in Oman is expected to save a huge cost and enhance expertise in the field. This project leads to a start- up companies that ensure the development and maintenance of those devices. To develop further the recent biologically inspired concepts dealing with locomotion controller to include complex patterns with reflexes. To develop Algorithms that can be implemented on low-cost microchips and have the capability of self-learning by given knowledge in the form of: Simpler mathematical models (FFT, equations solver) Statistical modeling Mechanical concepts (Fast algorithm for Inverse Kinematics solver) Major Phases of the work: There are two phases for this work; Phase-I: consists of developing a Stimulator with locomotion controller using humanoid robot that can generate a gait with the main features of the human gait. Both supervised and unsupervised learning algorithms will be applied. Phase-II: consists of designing the conversion unit that converts the actuator signal to EMGs pulses suitable to control the patient s muscles. Literature Review Commencing with the foot drop disease itself, the relevant literature for the two phases of the proposed project is described as follows: Phase-I represents the research framework of the current project proposal. Phase-II consists of making the inverse mapping or conversion of the robot actuator signals into EMGs pulses and develop the appropriate safety measures for conducting experiment on patients. Foot Drop Disease Foot drop is usually a symptom of a greater problem that may happen in human body such as nerve damage, muscle damage, abnormal anatomy, neurological damage, tumors, neuro-spinal injury, diabetes, neuropathies (a functional disturbance or pathological change in the peripheral nervous system), stroke, dorsiflexor injuries, drug toxicities, multiple sclerosis (MS), amyotrophic lateral sclerosis (ALS, disease of the nerve cells in the brain and spinal cord that control voluntary muscle movement), Parkinson's disease (a disorder of the brain that leads to shaking and difficulty with walking, movement), and muscular dystrophy (a group of inherited disorders that involve muscle weakness and loss of muscle tissue, which get worse over time). The disease is characterized by the inability or difficulty in moving the ankle and toes upward (dorsiflexion). Basically, dorsiflexion is moving the ankle towards the sky, and the plantarflexion is moving the ankle towards the ground. In walking, while stepping forward, the front of the foot must be lifted upward to prevent the foot from dragging along the ground, which results into an abnormal gait.