Balancing control of AIT leg exoskeleton | |
| Author | Narong Aphiratsakun |
| Call Number | AIT Diss. no.ISE-10-02 |
| Subject(s) | Balancing of machinery Skeleton Artificial legs |
| Note | A dissertation submitted in partial fulfillment of the requirements for the degree of Doctor of Engineering in Mechatronics, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Dissertation ; no. ISE-10-02 |
| Abstract | This dissertation, focuses on the design of mechanical hardware, controller architectures, simulation model and balancing control of the Asian Institute of Technology Leg EXoskeleton-I (ALEX-I). ALEX-I has been developed to assist patients suffering from paraplegia or immobility due to the loss of power on lower limbs. ALEX-I has 12 DOF (6 DOF for each leg: 3 at the Hip, 1 at the knee and 2 at the ankle), controlled by 12 DC motors. The concept of Zero Moment Point (ZMP) is applied for on this work. The balanced posture set-points (joint trajectories) under ZMP criterion are generated offline. The ZMP based set points are provided as the desired postures to ALEX-I. Ground Contact Point (GCP) is used to find the “ZMP-like in real time”. GCP data is obtained by placing 4 load cells forming a force plate on each foot of ALEX-I. This GCP data is then compared with the reference ZMP. Uncontrollable movement of the upper part of wearer, uncertainties of the model parameters, noises, backlash, and joints gaps are considered as disturbance. In this research, two control algorithms are proposed: ZMP based Jacobian Compensation Control (ZMP-JCC) and ZMP based Fuzzy Logic Control (ZMP-FLC). Jacobian Compensation Control (JCC) analyzes the required set point data to maintain stability of ALEX-I. The 12 outputs from JCC acts as the compensated angles for the 12 joints in the roll, pitch and yaw axis that retain the actual ZMP in the convex hull region of the supporting area. Fuzzy Logic Controller (FLC) determines the modified set points based on postures balancing sensed by load cells. FLC is applied to the joints that have backlash problem; ankle joints for ALEX-I case. The 4 outputs from FLC are the compensated angles of left and right ankles joints in roll and pitch axis that make the actual ZMP locate in the convex hull. ZMP-FLC is easily adjusted. Simulation and Experimental results in this dissertation validate the efficiency of the proposed algorithms. |
| Year | 2010 |
| Corresponding Series Added Entry | Asian Institute of Technology. Dissertation ; no. ISE-10-02 |
| Type | Dissertation |
| School | School of Engineering and Technology (SET) |
| Department | Department of Industrial Systems Engineering (DISE) |
| Academic Program/FoS | Industrial Systems Engineering (ISE) |
| Chairperson(s) | Manukid Parnichkun; |
| Examination Committee(s) | Afzulpurkar, Nitin V. ;Dailey, Matthew N.; |
| Scholarship Donor(s) | Assumption University ;Royal Thai Government; |
| Degree | Thesis (Ph. D.) - Asian Institute of Technology, 2010 |