Tadashi Asaoka

Determining an optimal multiarticular muscle arrangement of a musculoskeletal robot for a specific motion using human motion data

In this paper, we propose a method to determine an optimal multiarticular muscle arrangement for a specific robot motion. Multiarticular muscles contribute to the realization of musculoskeletal robots with dynamic motion performance similar to humans and animals. However, the dynamic motion performance is affected by arrangement of the multiarticular muscles. Therefore, the arrangement is very important for the robots. In previous researches, muscle arrangements of robots were based on ones of humans and animals. However, we suppose that a more optimal muscle arrangement than any other one of humans and animals can be found by limiting robot motions. Therefore, in this research, we focus on a specific robot motion, and searched for an optimal multiarticular muscle arrangement for the specific robot motion. Specifically, we estimated force properties in the specific robot motion. The force properties were estimated by using human motion data corresponding to the specific motion. Then, on the basis of the evaluation of the force properties, we searched for the optimal muscle arrangement from among 736,281 of possible arrangements. Furthermore, we demonstrate the effectiveness of our method using simulation experiments. As a result, the search results indicate that there is a more optimal muscle arrangement than any other one of humans and animals on condition that we focus on the specific motion.

Design and development of a compressor-embedded pneumatic-driven musculoskeletal humanoid

Although pneumatic robots are expected to be physically friendly to humans and human-environments, large and heavy air sources and reservoir tanks are a problem to build a self-contained pneumatic robot. This paper proposes a compressor-embedded pneumatic-driven humanoid system consisting of a very small distributed compressors and hollow bones as air reservoir tanks as well as the structural parts. Musculoskeletal systems have possibility of doing dynamic motions using physical elasticity of muscles and tendons, coupled-driven systems of multi-articular muscles, and so on. We suppose a pneumatic driven flexible spine will be contribute to dynamic motions as well as physical adaptivity to environments. This paper presents the concept, design, and implementation of the compressor-embedded pneumatic-driven musculoskeletal humanoid robot named “buEnwa.” We have developed the pneumatic robot which embeds very small compressors and reservoir tanks, and has a multi-joint spine in which physically elastic elements such as rubber bands are attached, and the coupled-driving system of the spine and the shoulder. This paper also shows preliminary experiments of the real robot.

Robot motion evaluation of a musculoskeletal robot by simulation in terms of energy flow in the kinetic chain

Recently, many partner robots which coexist with humans in the human environment have been developed and actively investigated all over the world. For such robots, safety as well as motion ability similar to humans is important in order not to damage humans and the surrounding environment. It is essential for safety of a robot whose actuator power is low. A musculoskeletal robot with a humanlike muscle-skeleton structure gives one possibility for safety. The musculoskeletal robot comprises redundant and relatively low-power actuators (i.e., artificial muscle actuators). Accordingly, only a single actuator cannot produce dangerous power. An important issue in such a robot is how to effectively produce kinetic energy required to perform a desired motion by using the coordination of multiple actuators. Robot motion is caused by energy flow between each body of the robot through the kinetic chain. Therefore, in order to achieve the high motion performance of a robot with low-power actuators, it is important that mechanical energy generated by actuators is appropriately distributed to each body of the robot according to a desired motion. In this paper, we evaluated robot motion using simulation in terms of energy flow in the kinetic chain. The results indicate that the high motion performance of a robot with low-power actuators can be achieved by planning proper motion trajectories.

Determining the optimal multiarticular muscle arrangement of a musculoskeletal robot for a specific motion using dynamics simulation

In this paper, we propose a method to determine the optimal multiarticular muscle arrangement of a robot for a specific motion. Multiarticular muscles contribute to the realization of a musculoskeletal robot with dynamic motion ability similar to humans and animals. However, the ability is affected by the multiarticular muscle arrangement. In previous researches, the muscle arrangements of the robots were based on those of humans and animals. However, we suppose that a more suitable muscle arrangement than any other one of humans and animals can be found by limiting the variety of motions. Therefore, we focused on a specific motion, and furthermore, searched for the optimal multiarticular muscle arrangement for the specific motion. Specifically, we estimated the impulse properties of robots with a great variety of possible muscle arrangements. The impulse properties were calculated using dynamics simulation corresponding to the specific motion. Then, on the basis of the evaluation of the impulse properties, we found the optimal muscle arrangement from among 736,281 of possible muscle arrangements. Furthermore, we demonstrated the effectiveness of our method using simulation experiments. The results indicate that there is a more suitable muscle arrangement than any other one of humans and animals on condition that we focus on the specific motion.