Walking Motion Control of Biped Robotic Legs Inspired by Human Muscle Model for Adapting Variation of Vertical Load

Research on biologically inspired robots is advancing nowadays. Researhers observe mechanical properties and dynamic motions of many biological objects and such observations are used in order to implement on some robotic systems which can have similar characteristics. Many industrial robots and humanoid robots such as ASIMO, AIBO, QRIO are conventional type robots. Conventional humanoid robots and biological subjects differ in their mechanisms and control strategy. Biological subjects have musculoskeletal systems that can drive two joints at the same time while conventional robots use one joint drive mechanisms. Biological objects use their monoarticular and biarticular muscles in order to move their limbs and they have nearly perfect coordination of those muscles while jumping, landing, biped walking, running, etc. Muscle mechanism makes it easier to exert more force at the tip and the distribution of forces can be varied based on each activation of muscles. In this research, a biped robotic leg which is inspired by human leg muscle model is taken into account and walking behaviour of the leg in the existance of an external force is analised. Details of the mathematical modeling for such biologically inspired robotic leg is explained and simulation results for joint torque generation for different situations, especially in case of an vertical external force are presented. It has been shown that human has rational mechanism for output force control at the tip by taking the advantage of cooperative actuation of monoarticular and biarticular muscles. Especially, the magnitude of force is bigger in the direction from the fixed joint to the end effector. Human use this advantage for carrying a heavy body and also for jumping, walking and rejection of external forces. Additionally, using biarticular muscle improves the self-stability of the robotic leg by transfering energy between two adjacent joints. Dynamic motion is theorotically derived by taking mass, inertia, link lengths and gravity into account. Walking for robotic leg is formulated for both legs, one is when leg is carrying the body and react to external force, other is when leg is not in contact with the ground and taking one step forward. Joint torques are distributed to individual muscles by using a method called 2-norm which is used to calculate the efficient way of distribution of 2 values into 3. As for muscle model, a spring-damper system is considered so that flexibility can be achieved and, DC motor is used as actuator to tighten and loosen the muscle. Wires are used in order to transfer rotational motion into translational motion. Each muscle is controlled by a DC motor after calculating the necessary displacements of each muscles.報告番号: ; 学位授与年月日: 2012-03-22 ; 学位の種別: 修士 ; 学位の種類: 修士(工学) ; 学位記番号: ; 研究科・専攻: 工学系研究科電気系工学専