Tham khảo tài liệu 'new developments in biomedical engineering 2011 part 14', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 512 New Developments in Biomedical Engineering Salter et al. 1984 . However current CPM machines have some problems such as a lack of softness that inheres in human body a bulky size for use and noise emitted from the use of an electric motor. These problems disturb the ease and safety of use of the CPM machine at home. Hence we have designed a compact MH actuator and prototyped a CPM device using it. Fig. 15. Image of the elbow CPM machine using a pair of laminate film bellows and MH modules left and example of a motion pattern of the laminate film bellows added of an asymmetric elongation structure. The prototyped CPM device for an elbow joint is shown in Fig. 14. The installed MH actuator contained a small metal bellows. The output torque around an elbow was about 7 Nm at maximum which was selected based on the data obtained by the manual therapy motion of a physical therapist. The weight of this device was about kg and it is much lighter than that of a conventional CPM machine. The variable range of the mechanical compliance was to 15 deg Nm. Although this CPM machine has the potential to significantly improve joint disease its weight and wearability are still not enough for clinical use. In order to solve this problem we designed a different type of CPM machine which uses a laminate film bellows integrated into a soft MH actuator Ino et al. 2008 as shown in Fig. 15. The antagonistic mechanism composed of two soft MH actuators allows for soft actuation of the elbow joints and its stiffness can easily be controlled based on the sum of the inner pressure of both laminate film bellows Sato et al. 1996 . Moreover the range of the variable stiffness of human muscle at full activation was included in that of the MH actuator as shown already in Fig. 10. Thus the MH actuator using the laminate film bellows is suitable for a physical rehabilitation apparatus considering mechanical impedance matching. By using the MH actuator an extremely slow motion that is not
