Tamon Izawa

Development of musculoskeletal humanoid kenzoh with mechanical compliance changeable tendons by nonlinear spring unit

We have developed and studied musculoskeletal humanoids. Our goal is to achieve more human-like humanoids which can do natural and dynamic motions as well as humans. Especially, joint DOFs redundancy, mechanical joint compliance and great joint generating power are very important for humanlike dynamic motions and tasks, such as running, jumping, landing, throwing/kicking/catching a ball, and so on. This paper presents the concepts and aim of this project and also shows the outline of our latest results about development of new musculoskeletal humanoid Kenzoh, which is the succeeding version of our previous Kojiro.

Approach of “planar muscle” suitable for musculoskeletal humanoids, especially for their body trunk with spine having multiple vertebral

For making a robot that can help people safely, a musculoskeletal humanoid is an effective approach because of the ease of high degrees of freedom. However, many musculoskeletal humanoids have not yet been equipped with really humanlike bones and muscles. For making musculoskeletal humanoids with really humanlike bones and muscles, we thought that a “planar muscle” was a key. In wire-driven systems which many musculoskeletal humanoids adopted, one motor winds only one wire. However, this “linear muscle” needs one motor per wire and complex control systems as for one humanoid. Therefore, we developed “planar muscle” that controls several wires simultaneously by using two moving-pulleys bars and one motor. The “planar muscle” fits for musculoskeletal humanoids, especially for their body trunk with a spine having multiple vertebrae that need a lot of motors and complex control systems in the case of using linear muscles. Thus, we focus on developing a body trunk of a musculoskeletal humanoid that has multiple vertebrae and uses “planar muscles” for the body trunk. In this paper, we will show the concept of “planar muscle” and evaluate its motions with body-trunk model having multiple vertebrae that we have newly developed.

Biomimetic design of musculoskeletal humanoid knee joint with patella and screw-home mechanism

We are trying to create a novel musculoskeletal humanoid robot which has a humanlike structure. In this paper, we present a new knee joint which is usually simplified in robotics for high controllability. The knee joint has three human mimetic points, patella, screw-home mechanism and four-linked linkage. Patella is for a longer moment arm. Screw-home mechanism is for locking knee joint. Four-linked linkage is for making humanlike motion. Furthermore, we confirmed those performances by three experiments.

Biomimetic design and implementation of muscle arrangement around hip joint for musculoskeletal humanoid

Our laboratory has tackled the composition theory approach of clarifying the structure in the human body by imitating it. Focusing on the hip joint, which has many complex muscle groups, we estimated and implemented 15 muscles to restrict the hip joint. However, it was difficult to implement such a quantity muscles to musculoskeletal humanoid because motor space is limited and the frame must have strength. In this paper, we propose new design and implementation methodology of musculoskeletal humanoids. First, we propose the biomimetic design of the hybrid pelvis, which uses metal and resin. Second, to arrange the muscles in a way similar to a human, we propose the human mimetic muscle arrangement by using the internal organ space. As a result, we developed the high-strength and biologically inspired pelvis, and achieved human-like muscle attachment layout and muscle arrangement.

Design of powerful and flexible musculoskeletal arm by using nonlinear spring unit and electromagnetic clutch opening mechanism

We have been developed and studied musculoskeletal humanoids. Our next motivation is to achieve more human-like humanoids which can do natural and dynamic motions as well as humans. We newly designed musculoskeletal tendon-driven arm, which can achieve humanlike body structure, flexibility of joints and great power of joints for this motivation. This paper describes how to design such an arm and proposes the key mechanical design points, which is compact nonlinear spring unit and winding pulley equipped with electromagnetic clutch releasing mechanism. To show that these mechanisms improve greatly joint angular speed, we developed simple testing tendon-drive arm with these mechanism and did verification experiments. Finally, we present life-sized musculoskeletal arm using these mechanisms and some demonstrations.

Motion generation for human-robot collaborative pick and place based on non-obstructing strategy

This paper presents a model and motion generation method for the task of collaborative pick and place between a robot and a human. It often happens that the performance of a human is higher than that of a robot, in the case where the robot needs to recognize the environment as well as human behavior and move in a safe manner. This fact requires that the robot needs to make motions considering the timing of human motions and properly choose targets of manipulation beyond just considering one stroke of the human motion to enhance the total performance of the human-robot system. Accordingly, in this paper, we first express the robot and human using a state transition model. Then we present a method to generate a motion of the robot to increase future task executability of the human. This approach consists of two steps. In the first step, the system of the robot and human is simulated using 3D model till the near future. In the second step, the utility of the possible object-place layout is evaluated based on possible transportation hypotheses. We also evaluate the effectiveness of the proposed approach in simulation.

The trials of hula hooping by a musculo-skeletal humanoid KOJIRO nearing dancing motions using the soft spine

Many types of humanoid robots have been developed, but it is hard to find one with supple spine structure. To act in a proper manner with sophisticated, human-like motions, we believe that humanoid robots should make use of their spines effectively. To find out how to use the spine flexibly and elegantly, we focused on dancing, the art of beautiful movements. Dancing demands you to develop flexible and well coordinated movements of the torso, so we decided to pick up a movement of the sort and achieve it by the musculo-skeletal humanoid KOJIRO, in order to improve the skills needed for dancing. We took hula hooping as an ideal sample, and after generalizing the principal of hula hooping motion by an exclusive hula-hooping robot, we will describe the trials of hula hooping by KOJIRO as the first step toward dancing humanoids(Fig.1).

Motion control based on modification of the Jacobian map between the muscle space and work space with musculoskeletal humanoid

Many robots need body calibrations when their physical parameters are changed. This is because their motions are created with absolute variables such as links position and orientation. In this paper, we propose two methods using the musculoskeletal humanoid Kojiro. First, we apply a body control method with a Jacobian map between muscle space and work space, which is made with relative variables. Second, we apply a pose estimation method by making robots observe its own motion using its vision to get relations between the pose and the environment. By these methods, we achieved the motion control without calibrations even when the physical parameters of the robots are changed.