Hybrid parallel compliant actuation for lower limb rehabilitation

• Applicant: Professor Dr.-Ing. Steffen Leonhardt
• Subject Area: Biomedical Systems Technology
• Term: from 2018 to 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 392037132

• Final Report Year: 2022

Final Report Abstract

The overall aim of the DFG-NSFC project HYPACAl was to develop methods to design and control hybrid parallel compliant actuation for lower limb rehabilitation. For this purpose, the project was divided into 6 WPs from requirement analysis, mechanical and electrical development of the prototypes, control design, to evaluation. In requirement analysis, we performed reference measurement on healthy volunteers in the motion capture laboratory to derive general and specific requirements for all three main components: the actuator, the parallel elastic component, and the exoskeleton structure. The German and the Chinese groups followed separated approaches for the PEA: coil springs and flat spiral springs. Two prototypes of exoskeleton utilizing PEA have been developed at MedIT and Tsinghua. Mathematical models including actuators dynamics and exoskeleton and human gait kinematics and a new method for model parameter identification have been developed. Both groups followed different control approaches from actuator level (a stand-alone component on a mechanical testbench) to the entire exoskeleton during sit-to-stand and periodic walking. We demonstrated the effect of PEA for exoskeleton applications: a significant reduction in peak power, step energy and peak current. The peak power was reduced by almost 40% at a gait speed of 0.31 m/s. Furthermore, the advantages of hybrid control between exoskeleton and FES have been investigated and demonstrated. A real-time system to control exoskeleton and the FES device from Hasomed has been implemented. We designed controllers for two scenarios: control of the ankle joint with FES during periodic walking with exoskeleton, and hybrid control of the rectus femoris by utilizing FES for reduction of the required peak motor power during sit-to-stand. The results have been published in 8 scientific journals and 5 conferences.

Publications

• Design and Analysis of a Clutched Parallel Elastic Actuator. Actuators, 8(3), 67.
  Penzlin, Bernhard; Enes, Fincan Mustafa; Li, Yinbo; Ji, Linhong; Leonhardt, Steffen & Ngo, Chuong
  
• Design of the Clutched Variable Parallel Elastic Actuator (CVPEA) for Lower Limb Exoskeletons. 2019 41st Annual International Conference of the IEEE Engineering in Medicine and Biology Society (EMBC), 4436-4439. IEEE.
  Li, Yinbo; Li, Zhibin; Penzlin, Bernhard; Tang, Zihan; Liu, Yali; Guan, Xinyu; Ji, Linhong & Leonhardt, Steffen
  
• Effects of Ankle Joint Motion on Pelvis-Hip Biomechanics and Muscle Activity Patterns of Healthy Individuals in Knee Immobilization Gait. Journal of Healthcare Engineering, 2019, 1-10.
  Guan, Xinyu; Kuai, Shengzheng; Song, Liang; Liu, Weifeng; Liu, Yali; Ji, Linhong & Wang, Rencheng
  
• Analysis, Design, and Preliminary Evaluation of a Parallel Elastic Actuator for Power-Efficient Walking Assistance. IEEE Access, 8, 88060-88075.
  Li, Yinbo; Guan, Xinyu; Li, Zhibin; Tang, Zihan; Penzlin, Bernhard; Yang, Ze; Leonhardt, Steffen & Ji, Linhong
  
• Conceptual design, modeling and control of a rigid parallel serial-elastic actuator. at - Automatisierungstechnik, 68(6), 410-422.
  Penzlin, Bernhard; Leipnitz, Anja; Bergmann, Lukas; Li, Yinbo; Ji, Linhong; Leonhardt, Steffen & Ngo, Chuong
  
• Design and Preliminary Validation of a Lower Limb Exoskeleton With Compact and Modular Actuation. IEEE Access, 8, 66338-66352.
  Li, Yinbo; Guan, Xinyu; Han, Xinyu; Tang, Zihan; Meng, Kuilin; Shi, Zhanpeng; Penzlin, Bernhard; Yang, Yilin; Ren, Junli; Yang, Ze; Li, Zhibin; Leonhardt, Steffen & Ji, Linhong
  
• Design and First Operation of an Active Lower Limb Exoskeleton with Parallel Elastic Actuation. Actuators, 10(4), 75.
  Penzlin, Bernhard; Bergmann, Lukas; Li, Yinbo; Ji, Linhong; Leonhardt, Steffen & Ngo, Chuong
  
• Interactive gait control of an active lower limb exoskeleton using insole FSR for detection of patient’s movement intention. Biomed. Eng, 66(s1), S161-S162
  Penzlin, B., Lyu C., Bergmann, L., Benner, C., Li, Y., Ji, L., Lüken, M., Leonhardt, S. & Ngo, C.
  
• Dynamic Parameter Identification of a Human-Exoskeleton System With the Motor Torque Data. IEEE Transactions on Medical Robotics and Bionics, 4(1), 206-218.
  Li, Yinbo; Guan, Xinyu; Li, Wei; Penzlin, Bernhard; Liu, Kaiqi; Yang, Ze; Liu, Bing; Leonhardt, Steffen & Ji, Linhong