In this paper, we propose a shape computation algorithm for quasi-static shape transition of a planar closed elastica which has a function as an impulse force generator utilizing a snap-through buckling of an elastic strip. The proposed algorithm has an advantage to compute the shape of the closed elastic more stably and quickly than the one to which the shooting method simply applied since it is based on mechanistic equations where an unstable computation factor has been eliminated. The proposed algorithm is written in the forms extensible to shape computation for spatial closed elastica. This good property is based on our modeling where a continuum elastic strip is approximated by a serial chain of multiple rigid links with elastic joints familiar with robotics. Effectiveness of the proposed algorithm is verified by shape transition simulation for planar closed elastica including snap-through buckling usually difficult to compute due to its instable nature. An example of shape transition simulation for spatial closed elastica is also shown for illustrating extension to 3-dimensional cases.
This paper focuses on the feedforward position control for a musculoskeletal system which has two links, two joints and six muscles. This feedforward control method utilizes the resultant torque generated by inputting the internal force among muscles balancing at a desired posture. Therefore, any sensory feedback is not necessary for positioning. The motion convergence is extremely sensitive, namely it strongly depends on muscular arrangement of a musculoskeletal system. Focusing on the potential filed generated by the input of internal force, this paper analyzes the motion convergence from the quasistatic viewpoint. In this analysis, the muscular lengths along with the joint angles are approximated by Taylor expansion. After demonstration of the reliability of the approximation, Hessian matrix of the potential field is assessed to clarify the quasistatic condition of the motion convergence at a desired posture.
In this paper, we provide a essence of the risk management sheet that was used to obtain the world-first certificate of ISO/DIS 13482:2011 for “Robot Suit HAL® for Well-being,” and discuss how it could be applicable to more common wearable walking assistant robots. We hope our experiences and knowledge will help overcoming the so-called “valley of death” towards commercialization of the personal care robots.
This paper proposes a controller for the jumping motion of the 3-dimensional snake robot which has passive wheels and active universal joints. We assume that the snake robot jumps from the initial posture which some forward links are lifted up. First, we derive a dynamic model of the robot with considering the contact force and the frictional force between the robot and the flat surface. Next, we propose a controller which the snake robot jumps without slipping and the evaluation function to select the initial posture with consideration of the constraint force ellipse. Simulation and experimental results show the effectiveness of the proposed controller and the evaluation function.
In practical use of automatic guided vehicles, magnetic markers are widely used. However, an approach of which pattern of magnetic intensity in usual environment is defined as landmarks is not investigated. This reason is that it is difficult to be known environmental magnetic field since magnetic intensity is invisible. This paper shows investigation of environmental magnetic field in actual environment and describes implementation of the magnetic based navigation, magnetic navigation method. As the magnetic investigation, magnetic intensity of the mounted devices in a mobile robot was measured, and condition of efficient layout of the devices was obtained. By the measurement of environmental magnetic field in mentioned condition, pattern of magnetic intensity that is suitable as a landmark is shown in this paper. The mobile robot records magnetic intensity on its travel path as magnetic map, and achieves stable navigation based on the magnetic map. In this paper, performance of the magnetic navigation method is shown by an experiment.