New Medical Rehabilitation System
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2. system 2 for forefoot support which will have a rotation on the ankle zone (G
frame);
3. system 3 for vibration excitation of the muscles, especially for forefoot (on G
frame).
The first system consists of one stepper motor, which is moving through a belt a
frame on which the leg is fastened. The motor is a stepper one, so the control is very
easy to implement.
The motion is transmitted to an L-frame, which has a linear guide on the bottom
and is connected on a parallelogram system in the upper part. Also, this frame is
sustaining the system 2 which only has a rotational movement of the patient foot.
The movement is generated using a second stepper motor.
The simulation software is using the D’Alemberts principle, and considering a
continuous structure with a discretization in finite elements the analysis considers
the equation function of time, t [13]:
M · ¨
u + C · ˙
u + K · u = f (t)
(1)
where
M is the structural mass,
C is the damping,
K is the stiffness matrices,
u is the vector of displacement,
˙
u is the vector of velocity,
¨
u is the vector of acceleration,
f (t) is the vector of applied forces.
All the parameters which are necessary for the simulation have been obtained from
the 3D model using an automated mixed meshing with 74,807 nodes and 38,507
elements where each element is tetrahedral and considering as material DuPont
Delrin 127UV NC010 which is acetal resin and the structure is filled with water
[15].
Using a 3D simulation software, we focus on the forefoot frame, we have analyzed
the modal behavior, and we obtain the frequencies of the first four deformation
modes, as can be seen in Fig. 2 which has low frequencies because the material and
the structure geometry introduce a high stiffness, and the forefoot frame is filled with
water. Also, the solver used Direct Sparse solver has the tendency to over-stiffen the
model, resulting extremely low-frequency values.
The kinematic model and the vibration analyses were made in other papers and
permit us to conclude that the structure has some advantages: It is cheap and easy to
build, and it is portable and has a very low natural frequency. But it has some disadvantages, it is not stable, and the motion of the tibia frame is very slow. Therefore,
we analyze a second system which is made from steel and has fewer elements.
269
2. system 2 for forefoot support which will have a rotation on the ankle zone (G
frame);
3. system 3 for vibration excitation of the muscles, especially for forefoot (on G
frame).
The first system consists of one stepper motor, which is moving through a belt a
frame on which the leg is fastened. The motor is a stepper one, so the control is very
easy to implement.
The motion is transmitted to an L-frame, which has a linear guide on the bottom
and is connected on a parallelogram system in the upper part. Also, this frame is
sustaining the system 2 which only has a rotational movement of the patient foot.
The movement is generated using a second stepper motor.
The simulation software is using the D’Alemberts principle, and considering a
continuous structure with a discretization in finite elements the analysis considers
the equation function of time, t [13]:
M · ¨
u + C · ˙
u + K · u = f (t)
(1)
where
M is the structural mass,
C is the damping,
K is the stiffness matrices,
u is the vector of displacement,
˙
u is the vector of velocity,
¨
u is the vector of acceleration,
f (t) is the vector of applied forces.
All the parameters which are necessary for the simulation have been obtained from
the 3D model using an automated mixed meshing with 74,807 nodes and 38,507
elements where each element is tetrahedral and considering as material DuPont
Delrin 127UV NC010 which is acetal resin and the structure is filled with water
[15].
Using a 3D simulation software, we focus on the forefoot frame, we have analyzed
the modal behavior, and we obtain the frequencies of the first four deformation
modes, as can be seen in Fig. 2 which has low frequencies because the material and
the structure geometry introduce a high stiffness, and the forefoot frame is filled with
water. Also, the solver used Direct Sparse solver has the tendency to over-stiffen the
model, resulting extremely low-frequency values.
The kinematic model and the vibration analyses were made in other papers and
permit us to conclude that the structure has some advantages: It is cheap and easy to
build, and it is portable and has a very low natural frequency. But it has some disadvantages, it is not stable, and the motion of the tibia frame is very slow. Therefore,
we analyze a second system which is made from steel and has fewer elements.