Abstract
Variable Stiffness Actuators (VSAs) emerged as an alternative to conventional actuators in a variety of applications, such as walking robots and service robotics. New requirements, which were obviated in the design of rigid actuators, must be accounted for during the mechanical design of such new devices. Among them, we find the possibility of tunning the natural frequency of the mechanical system or damage reduction in case of impacts A multitude of solutions have been already proposed in the literature, each characterized by the kind of mechanism in charge of implementing the equilibrium position and the stiffness of the joint. With this work, we introduce a new actuator design based on tendon transmission, where a main motor controls the equilibrium position of the link while a secondary motor is in charge of modifying the joint stiffness. Unlike existing actuators, our proposal achieves a wide range of stiffness values, from close to zero up to completely rigid. Another distinguishing feature of the new design is the existence of a torque threshold, such that variable stiffness only becomes effective once the load is above a certain predefined threshold.
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References
Hurst, J.W., Chestnutt, J.E., Rizzi, A.A.: An actuator with physically variable stiffness for highly dynamic legged locomotion. In: IEEE International Conference on Robotics and Automation (ICRA), vol. 5, pp. 4662–4667. IEEE (2004)
Van Ham, R., Vanderborght, B., Van Damme, M., Verrelst, B., Lefeber, D.: Maccepa, the mechanically adjustable compliance and controllable equilibrium position actuator: Design and implementation in a biped robot. Robotics and Autonomous Systems 55(10), 761–768 (2007)
Sugar, T.G., Hollander, K.W., Hitt, J.K.: Walking with springs. In: SPIE Smart Structures and Materials+ Nondestructive Evaluation and Health Monitoring, International Society for Optics and Photonics, pp. 797602–797602 (2011)
Vanderborght, B., Tsagarakis, N.G., Semini, C., Van Ham, R., Caldwell, D.G.: Maccepa 2.0: Adjustable compliant actuator with stiffening characteristic for energy efficient hopping. In: IEEE International Conference on Robotics and Automation (ICRA), pp. 544–549. IEEE (2009)
Albu-Schaffer, A., Eiberger, O., Grebenstein, M., Haddadin, S., Ott, C., Wimbock, T., Wolf, S., Hirzinger, G.: Soft robotics. IEEE Robotics & Automation Magazine 15(3), 20–30 (2008)
Bicchi, A., Tonietti, G.: Fast and “soft-arm” tactics. IEEE Robotics & Automation Magazine, 22–33 (2004)
Migliore, S.A., Brown, E.A., DeWeerth, S.P.: Biologically inspired joint stiffness control. In: IEEE International Conference on Robotics and Automation (ICRA), pp. 4508–4513. IEEE (2005)
Schiavi, R., Grioli, G., Sen, S., Bicchi, A.: Vsa-ii: A novel prototype of variable stiffness actuator for safe and performing robots interacting with humans. In: IEEE International Conference on Robotics and Automation (ICRA), pp. 2171–2176. IEEE (2008)
Vanderborght, B., Van Ham, R., Lefeber, D., Sugar, T.G., Hollander, K.W.: Comparison of mechanical design and energy consumption of adaptable, passive-compliant actuators. The International Journal of Robotics Research 28(1), 90–103 (2009)
Hurst, J.W., Chestnutt, J.E., Rizzi, A.A.: The actuator with mechanically adjustable series compliance. IEEE Transactions on Robotics 26(4), 597–606 (2010)
Eiberger, O., Haddadin, S., Weis, M., Albu-Schaffer, A., Hirzinger, G.: On joint design with intrinsic variable compliance: Derivation of the dlr qa-joint. In: IEEE International Conference on Robotics and Automation (ICRA), pp. 1687–1694. IEEE (2010)
Kim, B.S., Song, J.B.: Hybrid dual actuator unit: A design of a variable stiffness actuator based on an adjustable moment arm mechanism. In: IEEE International Conference on Robotics and Automation (ICRA), pp. 1655–1660. IEEE (2010)
Hyun, D., Yang, H.S., Park, J., Shim, Y.: Variable stiffness mechanism for human-friendly robots. Mechanism and Machine Theory 45(6), 880–897 (2010)
Wolf, S., Hirzinger, G.: A new variable stiffness design: Matching requirements of the next robot generation. In: IEEE International Conference on Robotics and Automation (ICRA), pp. 1741–1746. IEEE (2008)
Jafari, A., Tsagarakis, N.G., Caldwell, D.G.: Awas-ii: A new actuator with adjustable stiffness based on the novel principle of adaptable pivot point and variable lever ratio. In: IEEE International Conference on Robotics and Automation (ICRA), pp. 4638–4643. IEEE (2011)
Wolf, S., Eiberger, O., Hirzinger, G.: The dlr fsj: Energy based design of a variable stiffness joint. In: IEEE International Conference on Robotics and Automation (ICRA), pp. 5082–5089. IEEE (2011)
Catalano, M.G., Grioli, G., Garabini, M., Bonomo, F., Mancinit, M., Tsagarakis, N., Bicchi, A.: Vsa-cubebot: A modular variable stiffness platform for multiple degrees of freedom robots. In: IEEE International Conference on Robotics and Automation (ICRA), pp. 5090–5095. IEEE (2011)
Catalano, M.G., Grioli, G., Bonomo, F., Schiavi, R., Bicchi, A.: Vsa-hd: From the enumeration analysis to the prototypical implementation. In: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pp. 3676–3681. IEEE (2010)
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Martínez, J.L., Blanco, J.L., Vallejo, D.G., Torres, J.L., Fernández, A.G. (2014). AVASTT: A New Variable Stiffness Actuator with Torque Threshold. In: Armada, M., Sanfeliu, A., Ferre, M. (eds) ROBOT2013: First Iberian Robotics Conference. Advances in Intelligent Systems and Computing, vol 252. Springer, Cham. https://doi.org/10.1007/978-3-319-03413-3_42
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DOI: https://doi.org/10.1007/978-3-319-03413-3_42
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