A novel methodology of calculating the human-machine interactive force for a head-neck exoskeleton
A new method based on the dynamic model of the head-neck exoskeleton (HN-EXO) is presented for calculating the external forces/torque imposed on the platform. First, force analysis is conducted on each leg of the HN-EXO, and the Newton-Euler method is adopted to establish the relationship between the driven torques and the forces at the spherical joint. Second, a dynamic analysis is performed on the sensor group, and the relationship between the forces at the spherical joint and the feedback of the sensor assembled in the joint space is established. Third, the equation between the driven torque and the feedback of the sensor is derived based on the previous work. Fourth, Newton-Euler dynamic equations are incorporated into the system to determine the relationship between the human-machine interactive force and the feedback of the sensors. Finally, an experiment is conducted, the results of which are as follows. (1) The performance of the proposed algorithm is better than the existing one in terms of effectiveness, accuracy, and stability. (2) The maximum calculating time of the new method is 4.25×10-4 s, which is one-fifth of the control cycle period. Therefore, the new algorithm can be adopted to accomplish real-time control under the frequency of 500 Hz.
KeywordsExoskeleton Stewart platform Human-machine interactive force Helmet-mounted display Dynamic analysis Assistive device
Unable to display preview. Download preview PDF.
- P. Li, H. B. Gu and D. S. Wu, Dimensional design and corresponding methodology for helmet mounted display with 6-DOF parallel manipulator based on requirements of head motion, Acta Aeronautica et Astronautica Sinica, 32 (4) (2011) 739–750 (in Chinese).Google Scholar
- P. Li, H. B. Gu, D. S. Wu and H. Liu, Research on the active compliance control of helmet mounted display with a 6-DOF parallel manipulator, Acta Aeronautica et Astronautica Sinica, 33 (5) (2012) 928–939 (in Chinese).Google Scholar
- A. Gillette and C. Reboulet, An isostatic six-component force and torque sensor, Proc. of Industrial Roboticsm, Chicago, Illinois, USA (1983) 102–111.Google Scholar
- T. Onodera, T. Yonezawa, M. Ding and H. Takemura, Force, stiffness and viscous damping control in six degrees of freedom of the ankle-foot rehabilitation assistive device, Transactions of Japanese Society for Medical & Biological Engineering, 52 (2) (2014) 88–96.Google Scholar
- Y. J. Sun, Y. W. Liu, M. H. Jin and H. Liu, Design of a novel six-axis force-torque sensor based on strain gauges by finite element method, Proc. of Intelligent Control and Automation, Shenyang, Liaoning, China (2014) 3387–3392.Google Scholar
- J. Zhao, X. Y. Wang and L. Zhang, Finite element analysis of six-dimension stiff force/torque sensor elastomer for robot, Proc. of Instrumentation Science and Technology, Jinan, Shandong, China (2002) 18–22.Google Scholar
- P. Li and D. S. Wu, The generalized interactive force calculation for the helmet mounted display with the 6URHS parallel manipulator, Proc. of Fuzzy Systems and Knowledge Discovery, Zhangjiajie, Hunan, China (2015) 394–400.Google Scholar
- P. Li, H. B. Gu and D. S. Wu, Dynamic model of helmet mounted display with a 6-DOF parallel manipulator and corresponding verification, China Mechanical Engineering, 24 (9) (2013) 1201–1209 (in Chinese).Google Scholar