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DESCRIPTION
MECHATRONICS SEMINAR PRESENTATION
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INTRODUCTION
The objective is to develop an artificial hand aimed at replicating the appearance and performance of the natural hand or to obtain a complete functional substitution of the natural hand.
Main problems to be solved in order to improve the performance of prosthetic hands are:
1) lack of sensory information gives to the amputee 2) lack of “natural” command interface. 3) limited grasping capabilities 4) unnatural movements of fingers during grasping.
DESIGN OF THE BIOMECHATRONIC HAND
• BIOMECHATRONIC DESIGN
• ARCHITECTURE OF THE BIOMECHATRONIC HAND
• ACTUATION SYSTEM
BIOMECHATRONIC DESIGN
The main requirements to be considered are:
- cosmetics - controllability - noiselessness - lightness - low energy consumption
ARCHITECTURE OF THE BIOMECHATRONIC HAND
It uses small actuators (two of each finger) and micro motors instead of one single large actuator and motor.
ACTUATION SYSTEM Heavy actuator system
Traditionalactuators One/two DOF’s
Low adaptability
Little contactareas
Low grasp robustness
Large forces
Micro actuator system
Micro actuators Small forces
High graspstability
Rise in contactareas
High grasp stability
Rise in DOF’s
SMOOVY Characteristics
3Gear stages1:125Transmission rate
25NMaximum load (radial)
40NMaximum load (axial)
3.2 gWeight20mm/sMaximum speed
12NNominal force
Kinematics architecture
The kinematics of each finger joints are:
MP (Meta carpophalengal) joint
PIP (Proximal interphalengal) joint
DIP (Distal interphalengal) joint
HAND PROTOTYPE
POSITION AND FORCE SENSORS
SENSORS 1) Tactile sensors 2) Proximity and range sensors 3) Position sensors 4) Hall effect sensors
HALL EFFECT SENSORS
There are two basic forms of this sensor, LINEAR $ THRESHOLD.
SENSORS CHARACTERISATION CHARACTERISATION OF POSITION SENSOR.
0
1
2
3
4
5
6
0 10 20 30 40 50 60 70 80 90joint angle(degree)
outp
ut v
olta
ge(v
)
CHARACTERIZATION OF FORCE SENSOR
CALIBRATION CURVE OF THE FORCE SENSOR
02468
10121416
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8OUTPUT VOLTAGE (V)
FOR
CE
(N)
FINGERED TRIP FORCE ANALYSIS
FUTURE IMPROVEMENTS
Natural fingers movements during grasping and force sensor measurements should be further investigated.
CONCLUSION
The biomechatronic design approach can lead to the development of hand and prostheses.
It requires low cost and low energy consumption for adequate autonomy (at least 8 hours between recharges).
THANK YOU
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