1
As per the given problem-statement, Robosapien is a manual robot designed to traverse over irregular terrain with deep crevasses by bridging them. It uses grasping and gripping techniques to lift the target objects at the accident sites. Hence, in short, the bot has the following mechanisms: »Locomotion »Gripping and grasping »Lifting
LOCOMOTION The locomotion of the bot depends on its wheel and the motors.Robosapien has four 200rpm motors coupled with gear for smooth travel. SPUR GEAR Spur gears or straight-cut gears are the simplest type of gear. They consist of a cylinder or disk with the teeth projecting radically, and although they are not straight-sided in form, the edge of each tooth is straight and aligned parallel to the axis of rotation. These gears can be meshed together correctly only if they are fitted to parallel shafts
The gear has a mechanical advantage that can be explained through a simple equation as below Torque Old X Angular Velocity Old = Torque New X Angular Velocity New The odd number gear wheels rotate in the same direction and the even number wheels have counter rotation.
WHEELS Galileo wheels :
2
The Galileo Wheel, which combines a wheel and a track in a single component. The simple mechanism, wheel to track, or track to wheel, enables switching back and forth between the two modes within seconds. The technology provides the benefits of both traditional transport elements: the wheel with its energy efficiency, smooth ride, maneuverability, minimal footprint and suitability for high speeds, and the tracks with their superb traction for overcoming obstacles, towing capability, smoothness of ride over rough terrain and the capability to climb up and down stairs. Mobility needs analysis of tracked vehicles, specifically tracked robots, whether large or small, shows that the majority of these would be better off on wheels most of the time, but for a short yet critical portion of their intended operation, must be on tracks to achieve their mission. Galileo has developed the ideal mo bility platform for robots, vehicles, wheelchairs and any other devices needing track and wheels simultaneously.
THE ROCKER BOGIE MECHANISM
:
The rocker bogie suspension is a mechanism that, along with a differential, enables the vehicle to passively keep all six wheels in contact with a surface even when driving on severely uneven 3
terrain. There are two key advantages to this feature. The first advantage is that the wheels’ pressure on the ground will be equilibrated. This is extremely important in soft terrain where excessive ground pressure can result in the vehicle sinking into the driving surface. The second advantage is that while climbing over hard, uneven terrain, all six wheels will nominally remain in contact with the surface and under load, helping to propel the vehicle over the terrain. The mechanism can be better understood better from the following video: http://www.youtube.com/watch?v=V3hqQ5rv_CI
GRASPING and GRIPPING MECHANISM: For this, a DC motor, clutches and gear is used. The motor is coupled with rope dat is suspended through a pulley. The grippers that is used to lift the objects are coupled with the gears. This entire system is suspended through the rope. Hence, the lowering and upward motion of the gripper is controlled by DC motor. When motor moves the driving gear the driven gear automatically moves in the opposite sense due to the meshing. This is used to move the gripping pads closer or farther from one another.
When two gears of unequal number of teeth are combined a mechanical advantage is produced, with both the rotational speeds and the torques of the two gears differing in a simple relationship.
Lifting: For lifting, we can make use of the hook system, whose lowering and upward motion can be controlled by a dc motor.
4
5