Design of a passive lower limb exoskeleton for walking assistance with gravity compensation

Abstract In this paper, a passive lower limb exoskeleton with hip and knee joints is proposed for walking assistance. The exoskeleton is designed with built-in spring mechanisms for gravity compensation of the human leg. A pair of mating gears is used to convert the tension force from the built-in springs into balancing torques at the hip and knee joints in order to overcome the influence of gravity. With the novel design, the exoskeleton has a compact layout with small protrusion, which improves its user acceptance and safety. In this paper, the working principle of the design for gravity compensation is described. A model is developed to analyze the effects of the design parameters. Simulations are conducted and the results show that the average absolute driving torque was reduced by 79.0% at the hip joint and 66.4% at the knee joint, with the use of this exoskeleton. Parametric study shows that lower gait speed, lower stiffness with larger pretension of the springs contribute to the maintenance of balance. A prototype of the leg exoskeleton was fabricated, and preliminary tests on healthy subjects verified usability of the exoskeleton.

[1]  R. Teasell,et al.  The Role of Task-Specific Training in Rehabilitation Therapies , 2005, Topics in stroke rehabilitation.

[2]  Sunil Kumar Agrawal,et al.  Gravity-Balancing Leg Orthosis and Its Performance Evaluation , 2006, IEEE Transactions on Robotics.

[3]  Mukul Talaty,et al.  Differentiating ability in users of the ReWalkTM powered exoskeleton: An analysis of walking kinematics , 2013, 2013 IEEE 13th International Conference on Rehabilitation Robotics (ICORR).

[4]  Chin-Hsing Kuo,et al.  A Novel One-DoF Gravity Balancer Based on Cardan Gear Mechanism , 2017 .

[5]  H. van der Kooij,et al.  A passive exoskeleton with artificial tendons: Design and experimental evaluation , 2011, 2011 IEEE International Conference on Rehabilitation Robotics.

[6]  Gert Kwakkel,et al.  Hemiplegic gait after stroke: is measurement of maximum speed required? , 2006, Archives of physical medicine and rehabilitation.

[7]  Jiansheng Dai,et al.  Kinematic analysis and optimization of a planar parallel compliant mechanism for self-alignment knee exoskeleton , 2018, Mechanical Sciences.

[8]  Gregory S. Sawicki,et al.  Reducing the energy cost of human walking using an unpowered exoskeleton , 2015, Nature.

[9]  Weihai Chen,et al.  A Novel Precision Measuring Parallel Mechanism for the Closed-Loop Control of a Biologically Inspired Lower Limb Exoskeleton , 2018, IEEE/ASME Transactions on Mechatronics.

[10]  Karl E. Zelik,et al.  Design of a Low Profile, Unpowered Ankle Exoskeleton That Fits Under Clothes: Overcoming Practical Barriers to Widespread Societal Adoption , 2019, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[11]  F. Reynard,et al.  The WalkTrainer—A New Generation of Walking Reeducation Device Combining Orthoses and Muscle Stimulation , 2009, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[12]  R. H. Nathan.  A Constant Force Generation Mechanism , 1985 .

[13]  Scott Kuindersma,et al.  Human-in-the-loop optimization of hip assistance with a soft exosuit during walking , 2018, Science Robotics.

[14]  R. Huston.  Principles of Biomechanics , 2008 .

[15]  Haoyong Yu,et al.  Multi-modal control scheme for rehabilitation robotic exoskeletons , 2017, Int. J. Robotics Res..

[16]  Reza Haghighi,et al.  Gravity-Balancing of Elastic Articulated-Cable Leg-Orthosis Emulator , 2019, Mechanism and Machine Theory.

[17]  Jian S. Dai,et al.  Mechanism design and analysis of a proposed wheelchair-exoskeleton hybrid robot for assisting human movement , 2019 .

[18]  Marcela Munera,et al.  Lokomat therapy in Colombia: Current state and cognitive aspects , 2017, 2017 International Conference on Rehabilitation Robotics (ICORR).

[19]  S.K. Agrawal,et al.  Theory and design of an orthotic device for full or partial gravity-balancing of a human leg during motion , 2004, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[20]  Hideo Fujimoto,et al.  A new gravity compensation mechanism for lower limb rehabilitation , 2009, 2009 International Conference on Mechatronics and Automation.

[21]  Vigen Arakelian,et al.  Gravity compensation in robotics , 2016, Adv. Robotics.

[22]  Minh Tran,et al.  Design and Experimental Verification of Hip Exoskeleton With Balance Capacities for Walking Assistance , 2018, IEEE/ASME Transactions on Mechatronics.

[23]  R. Seliktar,et al.  Design and Testing of a Functional Arm Orthosis in Patients With Neuromuscular Diseases , 2007, IEEE Transactions on Neural Systems and Rehabilitation Engineering.

[24]  J. Perry,et al.  Gait Analysis , 2024 .

[25]  W. Liao,et al.  Knee exoskeletons for gait rehabilitation and human performance augmentation: A state-of-the-art , 2019, Mechanism and Machine Theory.

[26]  Herman van der Kooij,et al.  XPED2: A Passive Exoskeleton with Artificial Tendons , 2014, IEEE Robotics Autom. Mag..

[27]  Marc Doumit,et al.  Review and analysis of recent development of lower extremity exoskeletons for walking assist , 2016, 2016 IEEE EMBS International Student Conference (ISC).

[28]  Michael Skipper Andersen,et al.  A compact 3-DOF shoulder mechanism constructed with scissors linkages for exoskeleton applications , 2019 .

[29]  Sunil K. Agrawal,et al.  Design of a Passive Gravity-Balanced Assistive Device for Sit-to-Stand Tasks , 2006 .

[30]  Kenan Koser,et al.  A cam mechanism for gravity-balancing , 2009 .

[31]  K. H. Low,et al.  Robot-assisted gait rehabilitation: From exoskeletons to gait systems , 2011, 2011 Defense Science Research Conference and Expo (DSR).

[32]  Steven H. Collins,et al.  An exoskeleton using controlled energy storage and release to aid ankle propulsion , 2011, 2011 IEEE International Conference on Rehabilitation Robotics.

[33]  Antonie J. van den Bogert,et al.  Exotendons for assistance of human locomotion , 2003 .

[34]  Yasuhisa Hasegawa,et al.  Restoration of Gait for Spinal Cord Injury Patients Using HAL With Intention Estimator for Preferable Swing Speed , 2015, IEEE Transactions on Neural Systems and Rehabilitation Engineering.