Authors:
Dimitar Chakarov
;
Ivanka Veneva
;
Pavel Venev
and
Mihail Tsveov
Affiliation:
Institute of Mechanics, Bulgarian Academy of Sciences, “Acad. G. Bonchev” str., Block 4, Sofia 1113, Bulgaria
Keyword(s):
Exoskeleton Arm, Electric Motors, Pneumatic Cylinders, Interaction Force, Patient, Harmonic Motion, Mechanical Impedance, Experiments, Simulations.
Abstract:
A new construction of upper limbs exoskeleton with hybrid drive was studied in this work. The paper presents mechanical structure and actuation of exoskeleton with hybrid drive including pneumatic cylinders and electric motors. In order to evaluate the transparency and safety, the capabilities of the exoskeleton in passive mode of interaction was estimated. A model of the interaction force between the patient and the exoskeleton arm in passive mode was built. The model was based on harmonious movements imposed in one joint of the exoskeleton arm. Experiments and simulations were performed to assess the interaction force between the patient and the exoskeleton because of the mechanical impedance of the device. The force of interaction was obtained from passive forces, such as inertial, frictional and gravitational forces, as well as from the elasticity of the pneumatics. The patient-initiated harmonic motion was studied in two cases-without pressure in the chambers and with pressure f
or gravity compensation. The results where demonstrated graphically. Conclusions where made about the behavior of the exoskeleton in the passive mode of interaction.
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