Controller-observer design and dynamic parameter identification for model-based control of an electromechanical lower-limb rehabilitation system

[EN] Rehabilitation is a hazardous task for a mechanical system, since the device has to interact with the human extremities without the hands-on experience the physiotherapist acquires over time. A gap needs to be filled in terms of designing effective controllers for this type of devices. In this respect, the paper describes the design of a model-based control for an electromechanical lower-limb rehabilitation system based on a parallel kinematic mechanism. A controller-observer was designed for estimating joint velocities, which are then used in a hybrid position/force control scheme. The model parameters are identified by customising an approach based on identifying only the relevant system dynamics parameters. Findings obtained through simulations show evidence of improvement in tracking performance compared with those where the velocity was estimated by numerical differentiation. The controller is also implemented in an actual electromechanical system for lower-limb rehabilitation tasks. Findings based on rehabilitation tasks confirm the findings from simulations.This work was partially financed by the Plan Nacional de I+D, Comision Interministerial de Ciencia y Tecnologia (FEDERCICYT) under the project DPI2013-44227-R and by the Instituto U. de Automatica e Informatica Industrial (ai2) of the Universitat Politecnica de Valencia.Valera Fernández, Á.; Díaz-Rodríguez, M.; Vallés Miquel, M.; Oliver, E.; Mata Amela, V.; Page Del Pozo, AF. (2017). Controller-observer design and dynamic parameter identification for model-based control of an electromechanical lower-limb rehabilitation system. International Journal of Control. 90(4):702-714. https://doi.org/10.1080/00207179.2016.1215529S702714904Åström, K. J., & Murray, R. M. (2010). Feedback Systems. doi:10.2307/j.ctvcm4gdkAtkeson, C. G., An, C. H., & Hollerbach, J. M. (1986). Estimation of Inertial Parameters of Manipulator Loads and Links. The International Journal of Robotics Research, 5(3), 101-119. doi:10.1177/027836498600500306Chia Bejarano, N., Maggioni, S., De Rijcke, L., Cifuentes, C. A., & Reinkensmeyer, D. J. (2015). Robot-Assisted Rehabilitation Therapy: Recovery Mechanisms and Their Implications for Machine Design. Emerging Therapies in Neurorehabilitation II, 197-223. doi:10.1007/978-3-319-24901-8_8Berghuis, H., & Nijmeijer, H. (1993). A passivity approach to controller-observer design for robots. IEEE Transactions on Robotics and Automation, 9(6), 740-754. doi:10.1109/70.265918Briot, S., & Gautier, M. (2013). Global identification of joint drive gains and dynamic parameters of parallel robots. Multibody System Dynamics, 33(1), 3-26. doi:10.1007/s11044-013-9403-6Canudas de Wit, C., & Fixot, N. (1991). Robot control via robust estimated state feedback. IEEE Transactions on Automatic Control, 36(12), 1497-1501. doi:10.1109/9.106170Canudas de Wit, C., & Slotine, J.-J. E. (1991). Sliding observers for robot manipulators. Automatica, 27(5), 859-864. doi:10.1016/0005-1098(91)90041-yCao, J., Xie, S. Q., Das, R., & Zhu, G. L. (2014). Control strategies for effective robot assisted gait rehabilitation: The state of art and future prospects. Medical Engineering & Physics, 36(12), 1555-1566. doi:10.1016/j.medengphy.2014.08.005Carretero, J. A., Podhorodeski, R. P., Nahon, M. A., & Gosselin, C. M. (1999). Kinematic Analysis and Optimization of a New Three Degree-of-Freedom Spatial Parallel Manipulator. Journal of Mechanical Design, 122(1), 17-24. doi:10.1115/1.533542Cazalilla, J., Vallés, M., Mata, V., Díaz-Rodríguez, M., & Valera, A. (2014). Adaptive control of a 3-DOF parallel manipulator considering payload handling and relevant parameter models. Robotics and Computer-Integrated Manufacturing, 30(5), 468-477. doi:10.1016/j.rcim.2014.02.003De Jalon, J.G. & Bayo, E. (1994). Kinematic and dynamic simulation of multibody systems: the real-time challenge. New York: Springer Verlag.Díaz, I., Gil, J. J., & Sánchez, E. (2011). Lower-Limb Robotic Rehabilitation: Literature Review and Challenges. Journal of Robotics, 2011, 1-11. doi:10.1155/2011/759764Díaz-Rodríguez, M., Iriarte, X., Mata, V., & Ros, J. (2009). On the Experiment Design for Direct Dynamic Parameter Identification of Parallel Robots. Advanced Robotics, 23(3), 329-348. doi:10.1163/156855308x397550Díaz-Rodríguez, M., Mata, V., Valera, Á., & Page, Á. (2010). A methodology for dynamic parameters identification of 3-DOF parallel robots in terms of relevant parameters. Mechanism and Machine Theory, 45(9), 1337-1356. doi:10.1016/j.mechmachtheory.2010.04.007Gautier, M. (1991). Numerical calculation of the base inertial parameters of robots. Journal of Robotic Systems, 8(4), 485-506. doi:10.1002/rob.4620080405Gautier, M., & Khalil, W. (s. f.). On the identification of the inertial parameters of robots. Proceedings of the 27th IEEE Conference on Decision and Control. doi:10.1109/cdc.1988.194738Jamwal, P. K., Hussain, S., & Xie, S. Q. (2013). Review on design and control aspects of ankle rehabilitation robots. Disability and Rehabilitation: Assistive Technology, 10(2), 93-101. doi:10.3109/17483107.2013.866986Janabi-Sharifi, F., Hayward, V., & Chen, C.-S. J. (2000). Discrete-time adaptive windowing for velocity estimation. IEEE Transactions on Control Systems Technology, 8(6), 1003-1009. doi:10.1109/87.880606Janot, A., Gautier, M., Jubien, A., & Vandanjon, P. O. (2014). Comparison Between the CLOE Method and the DIDIM Method for Robots Identification. IEEE Transactions on Control Systems Technology, 22(5), 1935-1941. doi:10.1109/tcst.2014.2299544Janot, A., Vandanjon, P.-O., & Gautier, M. (2016). A revised Durbin-Wu-Hausman test for industrial robot identification. Control Engineering Practice, 48, 52-62. doi:10.1016/j.conengprac.2015.12.017Jiménez-Fabián, R., & Verlinden, O. (2012). Review of control algorithms for robotic ankle systems in lower-limb orthoses, prostheses, and exoskeletons. Medical Engineering & Physics, 34(4), 397-408. doi:10.1016/j.medengphy.2011.11.018Khalil, W., Vijayalingam, A., Khomutenko, B., Mukhanov, I., Lemoine, P., & Ecorchard, G. (2014). OpenSYMORO: An open-source software package for symbolic modelling of robots. 2014 IEEE/ASME International Conference on Advanced Intelligent Mechatronics. doi:10.1109/aim.2014.6878246Marchal-Crespo, L., & Reinkensmeyer, D. J. (2009). Review of control strategies for robotic movement training after neurologic injury. Journal of NeuroEngineering and Rehabilitation, 6(1). doi:10.1186/1743-0003-6-20Meng, W., Liu, Q., Zhou, Z., Ai, Q., Sheng, B., & Xie, S. (Shane). (2015). Recent development of mechanisms and control strategies for robot-assisted lower limb rehabilitation. Mechatronics, 31, 132-145. doi:10.1016/j.mechatronics.2015.04.005Page, A., Candelas, P., & Belmar, F. (2006). On the use of local fitting techniques for the analysis of physical dynamic systems. European Journal of Physics, 27(2), 273-279. doi:10.1088/0143-0807/27/2/010Raibert, M. H., & Craig, J. J. (1981). Hybrid Position/Force Control of Manipulators. Journal of Dynamic Systems, Measurement, and Control, 103(2), 126-133. doi:10.1115/1.3139652Ramsay, J. O., & Silverman, B. W. (2005). Functional Data Analysis. Springer Series in Statistics. doi:10.1007/b98888Saglia, J. A., Tsagarakis, N. G., Dai, J. S., & Caldwell, D. G. (2013). Control Strategies for Patient-Assisted Training Using the Ankle Rehabilitation Robot (ARBOT). IEEE/ASME Transactions on Mechatronics, 18(6), 1799-1808. doi:10.1109/tmech.2012.2214228Vallés, M., Cazalilla, J., Valera, Á., Mata, V., Page, Á., & Díaz-Rodríguez, M. (2015). A 3-PRS parallel manipulator for ankle rehabilitation: towards a low-cost robotic rehabilitation. Robotica, 35(10), 1939-1957. doi:10.1017/s0263574715000120Vallés, M., Cazalilla, J. I., Valera, Á., Mata, V., & Page, Á. (2013). Implementación basada en el middleware OROCOS de controladores dinámicos pasivos para un robot paralelo. Revista Iberoamericana de Automática e Informática Industrial RIAI, 10(1), 96-103. doi:10.1016/j.riai.2012.11.009Vallés, M., Díaz-Rodríguez, M., Valera, Á., Mata, V., & Page, Á. (2012). Mechatronic Development and Dynamic Control of a 3-DOF Parallel Manipulator. Mechanics Based Design of Structures and Machines, 40(4), 434-452. doi:10.1080/15397734.2012.687292Wu, F. X., Zhang, W. J., Li, Q., & Ouyang, P. R. (2002). Integrated Design and PD Control of High-Speed Closed-loop Mechanisms. Journal of Dynamic Systems, Measurement, and Control, 124(4), 522-528. doi:10.1115/1.1513179Yang, C., Huang, Q., & Han, J. (2012). Decoupling control for spatial six-degree-of-freedom electro-hydraulic parallel robot. Robotics and Computer-Integrated Manufacturing, 28(1), 14-23. doi:10.1016/j.rcim.2011.06.002Yoon, J., Ryu, J., & Lim, K.-B. (2006). Reconfigurable ankle rehabilitation robot for various exercises. Journal of Robotic Systems, 22(S1), S15-S33. doi:10.1002/rob.2015

Economic complexity and jobs: an empirical analysis

This paper analyses the impact of economic complexity on the labour market using annual data on OECD countries for the period 1985-2008 and averaged data over the period 1990-2010 for 70 developed and developing countries with a large number of controls. We show that moving to higher levels of economic sophistication of exported goods leads to less unemployment and more employment, revealing that economic complexity does not induce job loss. Our findings remain robust across alternative econometric specifications. Furthermore, we place the spotlight on the link between products' embodied knowledge (sophistication) and labour market outcomes at the micro-level. We build a product-level index that attaches a product to the average level of unemployment (or employment) in the countries that export it. With this index, we illustrate how the development of sophisticated products is associated with changes in the labour market and show that the economic sophistication of exported goods captures information about the economy's job creation and destruction

Economic complexity and jobs: an empirical analysis

This paper analyses the impact of economic complexity on the labour market using annual data on OECD countries for the period 1985-2008 and averaged data over the period 1990-2010 for 74 developed and developing countries with a large number of controls. We show that moving to higher levels of economic sophistication leads to less unemployment and more employment, showing that economic complexity does not induce job loss. Our findings remain robust across alternative econometric specifications. Furthermore, we place the spotlight on the link between products’ embodied knowledge (sophistication) and labour market outcomes at the micro-level. We build a product-level index that attaches a product to the average level of unemployment (or employment) in the countries that export it. With this index, we illustrate how the development of sophisticated products is associated with changes in the labour market and show that the economic sophistication of an economy captures information about the economy’s job creation and destruction

Economic complexity and jobs: an empirical analysis

This paper analyses the impact of economic complexity on the labour market using annual data on OECD countries for the period 1985-2008 and averaged data over the period 1990-2010 for 74 developed and developing countries with a large number of controls. We show that moving to higher levels of economic sophistication leads to less unemployment and more employment, showing that economic complexity does not induce job loss. Our findings remain robust across alternative econometric specifications. Furthermore, we place the spotlight on the link between products’ embodied knowledge (sophistication) and labour market outcomes at the micro-level. We build a product-level index that attaches a product to the average level of unemployment (or employment) in the countries that export it. With this index, we illustrate how the development of sophisticated products is associated with changes in the labour market and show that the economic sophistication of an economy captures information about the economy’s job creation and destruction

Opportunity of Threat? Exploring Middle Manager Roles in the Face of Digital Automation

With the proliferation of automation technology, controversy concerning the impact of digital automation on middle-managers’ strategic importance is rising. Some scholars adopt an ‘automation-as-a-threat’ view to argue that digital automation replaces middle-managers’ strategic value. On the contrary, others take an ‘automation-as-an-opportunity’ view to underscore the role accumulation advantages digital automation offers for individuals in organizations. We acknowledge this debate and develop a contingency-based role-theoretical framework, suggesting that the impact of automation on middle-managers’ strategic involvement depends on: (a) the nature of the middle-management tasks subject to automation, and (b) the level of the individual middle-manager's task-related expertise and simultaneous role embeddedness – as defined by their position tenure. We test our framework using longitudinal survey data from German, Swiss and Austrian firms at four time points. Overall, our work takes an important step toward unravelling the complex and contingent impact of digital automation on middle-managers’ strategic involvement in contemporary organizations

Agricultural Innovation and Sustainable Development

This book deals with sustainable agriculture at a time of climate change. It seeks to identify a number of solutions to deal with the agricultural stresses caused by climate change. These range from the identification and cultivation of appropriate crop varieties and the adoption of climate adaptive agricultural practices. Significant sustainable agricultural innovation is required to deal with these challenges. Intellectual property rights (IPRs) may be of crucial importance for modern agriculture. They serve to make R&D in agriculture attractive, by encouraging investment in new technologies and generating tradeable assets. A number of the chapters of this book refer to the principal IPRs relevant to agricultural innovation, namely: (i) patents, which protect inventions; (ii) plant variety rights, which protect the breeding of new and distinct plant varieties; and (iii) trademarks and geographical indications, which facilitate the marketing of products by providing protection for the symbols of their manufacturing or geographic origin. The United Nations Climate Change Panel has urged the consideration of the agricultural practices of traditional communities and some of these practices particularly involving rice, banana, and brassica cultivation are explored in the book. This book is essential reading for officials of governments and international organizations concerned with sustainability, as well as scholars and students concerned with these subject

Preferred customer status, supplier satisfaction and their contingencies

Over the last decades, firms shift increasingly from traditional in-house value creation strategies to cooperative buyer–supplier relationships as a source of value creation and competitive advantage. To reap extensive benefits from relationships with suppliers, assuring supplier satisfaction and achieving preferred customer status are key for buyers. In the past, several mechanisms have been identified that influence supplier satisfaction and preferred customer status; however, little is known about the role of major contingency factors such as: product type, dependencies and power influencing them. This dissertation focuses on the potential of preferred customer status to mitigate the negative effects of buyer dependency, the influences of a buyer’s power usage on supplier satisfaction, and potential perception differences of preferred status in buyer-supplier relationships. Additionally, this dissertation adds novel methods (i.e. partial least squares point predictions and polynomial regressions with response surface modeling) together with a dyadic perspective to supplier satisfaction and preferred customer research. These methods enable an assessment of the predictive abilities of models, reveal curvilinear interaction effects and discover asymmetric relationships between factors, which would have not been discovered otherwise