Biometric hand mechanical engineering project

2. 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.

3. DESIGN OF THE
BIOMECHATRONIC HAND
• BIOMECHATRONIC DESIGN
• ARCHITECTURE OF THE
BIOMECHATRONIC HAND
• ACTUATION SYSTEM

4. BIOMECHATRONIC DESIGN
The main requirements to be considered
are:
- cosmetics
- controllability
- noiselessness
- lightness
- low energy consumption

5. ARCHITECTURE OF THE
BIOMECHATRONIC HAND
It uses small actuators (two of each finger)
and micro motors instead of one single
large actuator and motor.

7. ACTUATION SYSTEM
 Heavy actuator system
Traditional
actuators
One/two DOF’s
Low adaptability
Little contact
areas
Low grasp
robustness
Large forces

8. Micro actuator system
Microactuators Small forces
High grasp
stability
Rise in contact
areas
High grasp
stability
Rise in DOF’s

10. SMOOVY Characteristics
3
Gear stages
1:125
Transmission rate
25N
Maximum load
(radial)
40N
Maximum load
(axial)
3.2 g
Weight
20mm/s
Maximum speed
12N
Nominal force

11. Kinematics architecture
The kinematics of each finger joints are:
 MP (Meta carpophalengal) joint
 PIP (Proximal interphalengal) joint
 DIP (Distal interphalengal) joint

13. HAND PROTOTYPE

14. POSITION AND FORCE SENSORS
SENSORS
1) Tactile sensors
2) Proximity and range sensors
3) Position sensors
4) Hall effect sensors

16. HALL EFFECT SENSORS
 There are two basic forms of this sensor, LINEAR $
THRESHOLD.

17. SENSORS CHARACTERISATION
 CHARACTERISATION OF POSITION SENSOR.
0
1
2
3
4
5
6
0 10 20 30 40 50 60 70 80 90
joint angle(degree)
o
u
tp
u
t
v
o
lta
g
e
(v
)

18. CHARACTERIZATION OF FORCE SENSOR
CALIBRATION CURVE OF THE FORCE SENSOR
0
2
4
6
8
10
12
14
16
0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8
OUTPUT VOLTAGE (V)
FORCE
(N)

20. FINGERED TRIP FORCE ANALYSIS

21. FUTURE IMPROVEMENTS
Natural fingers movements during
grasping and force sensor measurements
should be further investigated.

22. 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).

23. THANK YOU