Recently, the need for assistive devices has increased due to the rapid increase in the aging society. Elderly have weakened muscles in their lower limbs and they are susceptible to chronic injuries because of falling on the ground. They need some assistance to walk normally by themselves. The real-time fall prevention is a challenging problem due to the quite short time needed for the system to respond. So, in this paper, a 4-DOF cane robot system is proposed to assist elderly during walking and prevent them from falling. It consists of a 3-DOF Omni-direction mobile platform and one DOF stick. The 4-DOF is selected to achieve the front falling and the lateral one. First, the dynamic model of the cane robot using Lagrange method is derived. Then the kinematic model for the follow in the front by the cane robot is introduced. During normal walking, a kinematic control is introduced while a dynamic control is proposed during falling. An impedance controller whose gains tuned by Genetic algorithm (GA) with force/torque constraints is developed. Three cost functions are proposed for the GA to achieve the minimum time response required for real-time fall prevention. The results prove that the 4-DOF is enough for the front and lateral fall prevention and the dynamic response of the developed controller is suitable for real-time fall prevention.
['Mohamed A. Naeem', 'Samy F. M. Assal', 'A. A. Abouelsoud']
Modeling and real-time dynamic control of cane robot for fall prevention