Study on remote motion control systems taking operators' safety and operability into account

Recently, proceeding of the aging society has encouraged research and development of power assist systems. The authors' research group studies on the assist system control using an assist cart as a rollator. The merit of the proposed system is the aging people walk by themselves using the cart as the assisting tool and it helps anti-aging. Most serious problems of the proposed system are the avoidance of fallings and collisions without losing operability. To solve the problem, this paper proposes the remote control system taking operators' safety and operability into account. The remote control has a possibility of the establishment of the cost-effective multiple target control systems by reducing the requirement for each control target system. However, because of the limitation of communication data capabilities, the controller cannot grasp the state of the controlled object completely. To grasp the state and keep the safety, the authors apply an evaluator in the remote control system. It detects the effect of the uncertainty and keeps the controlled object safe. In addition, as an interface for the users to avoid the collisions, this paper applies the stiffness control. Introducing the virtual spring into the control system, the proposed system prevents the controlled object to collide the obstacle, without losing operability. Based on an application example for the one-dimensional assist rollator collision avoidance, this paper reveals the practicality of the proposed system by conducting experiments and the simulations. The result shows the proposed way is one of the effective ways for applying a remote control system to the assist system problem.