Tham khảo tài liệu 'climbing and walking robots part 6', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | On Adjustable Stiffness Artificial Tendons in Bipedal Walking Energetics 143 sic behavior of OLASAT a simple 2-DOF model of bipedal walking is illustrated in section 3. It also summarized the normalized formulation of the equations of motion of the biped. Section 4 contains the calculation of the energy loss at the foot-touch-down. A controller to automatically adjust the stiffness of OLASAT is proposed in section 5. Then in section 6 computer simulations are carried out to demonstrate the effects of stiffness adjustment of OLASAT on energy efficiency during the single support stance phase. The mathematical model of the bipedal walking is developed in sections and . 2. Conceptual Design and Modeling of ASATs In this section three different conceptual designs of ASAT are developed. The conceptual designs have not been fabricated in this project. The first design section is a rotary adjustable stiffness artificial tendon that is a bi-directional tendon able to apply torque in a clockwise as well as a counter clockwise direction. The second design section is a unidirectional linear adjustable stiffness artificial tendon that uses the concept of changing the number of active coils of two series springs. Finally the third design section is a combination of two offset parallel springs that is an unidirectional tendon. The mathematical model of each tendon is developed. The advantages limitations of each concept and the potential applications to the development of a compliant actuation system are discussed in Ghorbani Wu 2009a . Rotary Adjustable Stiffness Artificial Tendon RASAT The Rotary Adjustable Stiffness Artificial Tendon RASAT is specially designed to provide a wide range of the angular stiffness. The schematic of RASAT is illustrated in Fig. 1. In RASAT a pair of compression springs is intentionally inserted between the two concentric input and output links. Each spring pair consists of a low stiffness spring with a stiffness of K1 and a .
