Team Gripper
EGR 557
Dr. Aukes
Design Optimization, Experiment Design, Data
Collection, and Analysis Plan
The proposed studies are:
● Determine the ideal position for the motor link attachment (lever that attaches to servo
pinion and pushes the bar)
● Determine the ideal number of springs to maximize gripping force without over torquing
the motor.
Borna M.
Awab A.
Aman D.
Topics
Motor link
Motor link
Number of springs
Number of springs
Design
Optimization
Primary
Secondary
Primary
Secondary
Experiment
Design
Primary
Secondary
Primary
Secondary
Data
Collection
x
x
Data
Visualization
x
x
Analysis
Primary
Secondary
Secondary
Primary
Conclusions
Primary
Secondary
Secondary
Primary
Figure 1: parameters for optimization
Description:
Motor Link Position:
“What is the ideal position for the motor link in order to maximize the output force?”
We know the maximum torque on the motor cannot exceed 0.555N-m. Hence the maximum
force exerted from the end effector is a function of maximum torque divided by the distance r.
Figure 1 shows distance r being the distance from servo pinion to the point on the actuating link
A where servo is attached. The value of r must be greater than 1cm and smaller than link A. And
the exerted force from the end effector can be determined by division of max torque of the motor
by the value of the length r. Different r values will be computed in the optimization for loop
(maximization).
Number of Springs:
“How many springs can we use to maximize the gripping force without over torquing the
motor?”
We need to determine the number of springs that will maximize the spring force needed for
optimal gripping force without over torquing the motor. In order to do so, we create a virtual link
from omega C to omega B. this will serve as the length of the spring. The alteration in the
magnitude of this virtual link is accounted as displacement in the spring. To measure the
displacement, projection of link A onto link C will be deducted from the magnitude of link C.
this is equivalent to projection of the spring length onto C. Now that we have spring
displacement, it can be used in accordance with variable S in figure 1 which is the function of
number of springs present (number of springs multiplied by the spring constant). Hence the
maximum number of the springs that won’t exceed the allowed torque of the motor is the
function of Nmax. Nmax will be the upper bound of the optimization through maximization, and
1 will be the lower bound. The for loop will run through different numbers of NK and will plot
the exerted torque of each value and simulate the results.
