1. Urban Search and Rescue (USAR) Robot
by Jeffrey Gould
Project Goals
This project explores the possibility of using hydraulically actuated articulated limbs, on a remotely operated robotic vehicle for use in hazardous environments.
Optimization of hydraulic cylinders
Command and Control
Hydraulic
Cylinder
Rigid
Skeleton
A variety of command and control
schemes will be examined. Below
are some key points.
Pivot
Radius
Describes
Minimum
Moment Arm
User interface
Tail Section
For Balance
Currently, the directional control valves are controlled by small, manually operated switches. This will be replaced by one or more of the following:
Joystick control. Motion of the joints will be controlled by joysticks.
Master/Slave. Manipulation of a miniature copy of the vehicle (with appropriate kinematics) will be used as the input device.
Haptic display. An extension of the master/slave method above is to develop a haptic interface for the vehicle.
An optimization scheme was used to reduce the size of the hydraulic cylinders used while still meeting rotation and torque requirements.The figure above is a graphical representation of the optimization process.
The figure above is a graphical representation of the scheme used. It ensures a minimum moment arm (red circle), and required rotation (blue lines) for the shortest possible cylinder.
Shorter cylinders mean reduced weight, cost, size and oil flow requirements.
Below are a set of mathematical equations that describe the constraints on an optimal cylinder.
“Shoulder”
Joint
“Wing”
Joint
“Elbow”
Joint
Communication
Ultimately it is desired to have a wireless interface between the user and the vehicle. This project will include the application of a suitable wireless communication method.
Schematic of hydraulic system
The schematic to the left shows the
plumbing for two hydraulic cylinders.
The current design calls for a total of
seven cylinders. The circuit shown is
typical of all cylinders.
Sponsor: FPMC Center
Advisor: Dr. Wayne Book
website:
Spring 2003