INTRODUCTION
GQ64 is not a robotics based machine. It is the simplest form of mechanism which runs with the help of mechanisms like
- gear drive
- belt drive
- motor drive
- chain and sprocket drive
Walking mechanism has been for long a dynamic and fast developing field of mechatronics. This huge interest not only derives from the obvious fact that the usage of legs resembles the way of movement of living animals, but also to its great advantage while moving on a rough, unstructured surface. Due to the possibility to stand on single, well defined points a flexible operation area is achieved.
As a drawback, efficiency and speed are not the strongest qualities of walking mechanism. When it comes to flat, even terrain, moving with wheels turns out to be the faster, more reliable way of locomotion.
The invention provides a walking device which stimulates a gait of a legged animal. The device includes a frame with spaced axial mounts, a leg, axially connected upper and lower rocker arms which limit reciprocating leg motion. The leg is driven by a connecting arm powered by a rotating crank. The position and configuration of the axial connecting sites establish a prescribed orbital path that the foot undertakes with
each revolution of the crank. Both rocker arms and the crank are axially mounted to the frame.
The leg has a hip joint axially connected to the upper rocker arm for limiting hip motion, a foot and a knee joint axially connected to the connecting arm. The connecting arm has three axial connecting sites, one for connecting to the knee, another to the crank, and a third connecting site defined as a centrally disposed elbow joint connecting site which connects onto the lower rocker arm and limits knee joint motion. Under power, crank rotation is transferred to the connecting arm causing the leg to move in an accurate reciprocating movement of a restricted actual pathway which stimulates the gait of the legged animal. The walking device may be manually powered or motorized by applying motorized power to the crank axles.
each revolution of the crank. Both rocker arms and the crank are axially mounted to the frame.
The leg has a hip joint axially connected to the upper rocker arm for limiting hip motion, a foot and a knee joint axially connected to the connecting arm. The connecting arm has three axial connecting sites, one for connecting to the knee, another to the crank, and a third connecting site defined as a centrally disposed elbow joint connecting site which connects onto the lower rocker arm and limits knee joint motion. Under power, crank rotation is transferred to the connecting arm causing the leg to move in an accurate reciprocating movement of a restricted actual pathway which stimulates the gait of the legged animal. The walking device may be manually powered or motorized by applying motorized power to the crank axles.
Klann mechanism is a planar mechanism designed to simulate the giant legged animal and function as a wheel replacement. Here we are using a single leg consists of a six – bar linkage made up entirely of pivot joint that converts rotating motion into linear motion. The linkage consists of the frame, a crank, two grounded rockers, and two couplers all connected by pivot joints. The proportions of each of the links in the mechanism are defined to optimize the linearity of the foot for one-half of the rotation of the crank.
MECHANISMS USED
- Technical Mechanism
Klann mechanistic mechanism
Klann mechanism is a planar mechanism designed to simulate the giant legged animal and function as a wheel replacement. Here we are using a single leg consists of a six – bar linkage made up entirely of pivot joint that converts rotating motion into linear motion. The linkage consists of the frame, a crank, two grounded rockers, and two couplers all connected by pivot joints. The proportions of each of the links in the mechanism are defined to optimize the linearity of the foot for one-half of the rotation of the crank.
The remaining rotation of the crank allows the foot to be raised to a predetermined height before returning to the starting position and repeating the cycle. Two of these linkages coupled together at the crank and one-half cycle out of phase with each other will allow the frame of a vehicle to travel parallel to the ground. The Klann linkage provides many of the benefits of more advanced walking vehicles without some of their limitations. It can step over curbs, climb stairs, or travel into an area that are currently not accessible with wheels but does not require microprocessor control or multitudes.
TRANSMITTING SYSTEM
Which type of system you need to provide the power into legs for translation motion , in this system crank are the most common part because the main power are transmitted in crank , crank rotates with his own center the leg are joint with the help of pivot .
Main type of transmitting
- Mechanical spider with gear mechanism
- Mechanical spider without gear
MOTIVATION
To overcome the previously mentioned problematic a practical solution would be to enable different ways of travelling for one robot, rolling and walking, to adapt it to a changing environment in an easy way. In this bachelor thesis this task is realized by implementing feet equipped with passive skates on a walking robot, deriving a skating trajectory and do first steps into optimization of this movement. One of the main reasons for this choice was that the robot stays in the environment it is geared to. Therefore not the whole robot, but only the feet had to be altered.
Concept Determination
Several concepts for feet giving the robot the opportunity to reach new environ-ments or studying new locomotion concepts were in mind. After reconsidering the potential of different approaches their number could be reduced to the following promising options
A single leg consists of a six-bar linkage made up entirely of pivot joints that converts rotating motion into linear motion. One hundred and eighty degrees of the input crank results in the straight-line portion of the path traced by the foot. The result of two of these linkages coupled together at the crank and one-half cycle out of phase with each other is a device that can replace a wheel and allow the frame of the vehicle to travel relatively parallel to the ground. The remaining rotation of the input crank allows the foot to be raised to a predetermined height before returning to the starting position and repeating the cycle.
These figures show a single linkage in the fully extended, mid-stride, retracted, and lifted positions of the walking cycle. These four figures show the crank (rightmost link in the first figure on the left with the extended pin) in the 0, 90, 180, and 270 degree positions.
SKATING
In this concept the robot travels a flat, unstructured surface by skating. Each leg should be equipped with passive wheels on the feet. By moving the feet in specific way thrust is induced. Designing the specialized feet and deriving a possible trajectory are the emphases of this approach. The goal would be to move faster on the floor than with legged locomotion
Selected Method of Skating, why???
It was decided to further pursuit this way of movement for a couple of reasons:First of all with eight legs on the floor a very stable system is attained. Furthermore, lifting the legs would lead to a dislocation of the robots center of mass.
That means dynamic calculations have to be applied leading to a more complex problem. Aside from that, feet equipped with skating rolls turned out to be quite heavy. When lifted up, high torques in the joints would be generated. That way the motors could be overloaded.
KLANN MECHANISTIC MECHANISM
This mechanism is based on simple kinematic chain, and kinematic chain based on links joint and pivots.
The study of Biological systems and methods has long intrigued Scientists and Engineers in their quest for a greater understanding of the world. Biological systems have managed over thousands of years to evolve many methods for completing tasks that are naturally impossible for humans such as re-growing missing limbs, breathing underwater and even flying. Although humans have managed to mimic some of these abilities through the inventions of submarines and airplanes, there are still many areas of engineering that these biological marvels can be applied to. Biometics, the study of Biological methods and systems and their implications toward robotic systems and engineering problems, is the term applied to this ancient art, and has gained prominence in recent years for its novel solutions.
moter specification
100RPM 12V DC geared motors for robotics applications. It gives a massive torque of 35Kgcm. The motor comes with metal gearbox and off-centered shaft.
Features
- 100RPM 12V DC motors with Metal Gearbox and Metal Gears
- 18000 RPM base motor
- 6mm Dia shaft with M3 thread hole
- Gearbox diameter 37 mm.
- Motor Diameter 28.5 mm
- Length 63 mm without shaft
- Shaft length 30mm
- 180gm weight
- 35kgcm torque
- No-load current =800 mA, Load current = upto 7.5 A(Max)a
12 Volt Conventional (aka Lead Acid) Type Battery Sizes
12 Volt lead acid or conventional motorcycle batteries can usually be distinguished by a row of plastic stoppers in the top (3 stoppers in a 6 volt battery & 6 stoppers in a 12 volt battery).
Lead acid batteries usually have higher & lower battery acid levels on the front & have a white/clear plastic lower casing.
Conventional motorcycle batteries reference numbers usually start with the letters YB, CB or GB (e.g YB14L-A2) or 12N (e.g 12N24-3).
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