10-04-2017, 07:26 PM
Axial Force Sensor for a Semi-Autonomous Snake Robot
[attachment=16690]
I. INTRODUCTION
Various developments in robotics concentrate on mobile
robots to aid humans in new ways in their work and life.
Typical examples are remote inspection and maintenance
devices, personal assistants, and rescue robots. This research
concentrates on a particular type of robot for inspection in
unstructured environments like rubble or rocks. This type,
snake like robots, was chosen because it can enter small holes,
go over large obstacles and cross gaps while keeping stability.
II. SOLUTION CONCEPT
This section will explain the solution concept and signal
processing algorithm for a three axial force sensor up to the
point that it is directly applicable to other robots.
A. 3D Measurement
The goal is to measure 3D forces on the two wheels of a
snake segment. For practical usage calibrations should be
kept to a minimum, and the output should be temperature
independent and aging resistant. Moreover, unknown
flexibilities will be present in both inner and outer frame as
the whole snake body is to be kept simple and light.
II. IMPLEMENTATION
A. Flexible Parts
Fig. 3 showed coil springs for the flexible parts, but these
would be too large and not likely have the same flexibility in
each direction. Instead, two parts were designed, shown in
Fig. 7, with four sets of beams connected into two almost full
circles each to get the desired flexibility and robustness. Each
part is 67mm x 61mm x 5mm. To prevent plastic deformation
X and Y movements are limited by the part itself, and Z is
limited by a parallel plate connecting the left and right side
belonging to the outer frame. Simulations showed a safety
factor of 3.7 when applying maximum forces in X, Y and Z.
CONCLUSION
To allow 3D autonomous adaptive motion of a snake robot
according to the direct surroundings, a successful three axial
force sensor was designed with the practical features needed
for mobile robots in unpredictable environments. This
adaptive motion will allow easier control of these robots and
provide the operator with a new type of feedback to improve
his awareness of the unseen setting. In addition, the only
attention needed for the sensor during usage is 3s of initial
calibration at startup.
[attachment=16690]
I. INTRODUCTION
Various developments in robotics concentrate on mobile
robots to aid humans in new ways in their work and life.
Typical examples are remote inspection and maintenance
devices, personal assistants, and rescue robots. This research
concentrates on a particular type of robot for inspection in
unstructured environments like rubble or rocks. This type,
snake like robots, was chosen because it can enter small holes,
go over large obstacles and cross gaps while keeping stability.
II. SOLUTION CONCEPT
This section will explain the solution concept and signal
processing algorithm for a three axial force sensor up to the
point that it is directly applicable to other robots.
A. 3D Measurement
The goal is to measure 3D forces on the two wheels of a
snake segment. For practical usage calibrations should be
kept to a minimum, and the output should be temperature
independent and aging resistant. Moreover, unknown
flexibilities will be present in both inner and outer frame as
the whole snake body is to be kept simple and light.
II. IMPLEMENTATION
A. Flexible Parts
Fig. 3 showed coil springs for the flexible parts, but these
would be too large and not likely have the same flexibility in
each direction. Instead, two parts were designed, shown in
Fig. 7, with four sets of beams connected into two almost full
circles each to get the desired flexibility and robustness. Each
part is 67mm x 61mm x 5mm. To prevent plastic deformation
X and Y movements are limited by the part itself, and Z is
limited by a parallel plate connecting the left and right side
belonging to the outer frame. Simulations showed a safety
factor of 3.7 when applying maximum forces in X, Y and Z.
CONCLUSION
To allow 3D autonomous adaptive motion of a snake robot
according to the direct surroundings, a successful three axial
force sensor was designed with the practical features needed
for mobile robots in unpredictable environments. This
adaptive motion will allow easier control of these robots and
provide the operator with a new type of feedback to improve
his awareness of the unseen setting. In addition, the only
attention needed for the sensor during usage is 3s of initial
calibration at startup.