Robots on a rough terrain
As per Wikipedia, a robot is a mechanical or virtual artificial agent, a machine that is guided by a computer program or electronic circuitry, to perform various actions through different algorithms whereas the field robotics deals with the design, construction, operation, and application of robots, as well as computer systems for their control, sensory feedback, and information processing. A robot can be both autonomous and semi-autonomous. They can be mobile and stationery as well. Another definition may define a robot as anything that works based on a mechanism (be it mechanical or electrical) and is capable of moving objects and sometimes itself can be classified as a robot. A robot might move on wheel-based system or on legs in a similar fashion to humans and animals. But the balanced wheel based system are appropriate mainly for predictable terrains, while the unpredictable ones need more control and stabilization. Less than half the earth's landmass is accessible to wheeled and tracked vehicles, still people and animals can go almost anywhere on Earth. It may seem due to the advanced mind and more control over their motions. Though these factors form a major part of it but at the same time the structural built is equally helpful. Similarly for a robot to access such locations they should be built with a similar structure and system to control their motion and to make them easily movable on generally inaccessible rough terrains. In many fields, there is a strong demand for high-tech mobile robots that are capable of moving on an unpredictable rough terrain. One of such applications is in medical field to aid people with difficulty in walking. Rough terrains may also include inclined hill paths, forest areas, a flat land with clumsy debris and also extra-terrestrial planetary surfaces. Though a few steps have been taken towards building such mechanisms but a lot of research needs to be carried out to attain the desired goal.
From a rat sized robot suitable for tiny spaces like pipe lines to a car sized robot like the Mars rover, all of them need to be prepared for unpredictable circumstances, not just their surroundings but also their ground. Hence, the robots for such purposes need to be provided with adjustable limbs. To travel on rough terrain, a legged system must use the available footholds, irrespective of them being isolated or hidden by the obstacles. An unbalanced wheeled or tread system may be equally helpful depending upon the terrain. The major purpose is to make the robot adaptable and conscious to its immediate surroundings. On technical grounds, the problem of traveling over rough terrain may include many subproblems, including path planning, terrain sensing, selections of foothold, and adjustment of step length. These problems are encountered using various complex systems consisting of electromechanical systems, transducers, various types of sensors, and advanced mechanisms and various algorithms. Such motion planning algorithms for rough terrains must also consider real world implementation issues. In many similar applications a robot may be required to autonomously plan a path from their current location to a distant goal location, avoiding physical obstacles and unreliable terrains present in their way. A simulation for rough terrain should be done on the software as well as in physical conditions.
Legged Robots can have excellent mobility along with high stability by selecting the supporting point of their leg and maintaining its body using the limbs. This motivates the development of robot vehicles that use limbs for their locomotion, thereby imitating the nature’s solutions for mobility. The behavior of a legged robot can be broken down into three primary activities: supporting the body with a vertical bouncing motion, controlling the attitude of the body, and by placing the feet in key locations to keep the robots balanced as they move. All the systems including power source, actuation, sensing, manipulation, locomotion and environmental interaction and navigation systems should co-ordinate perfectly among themselves to make the robot respond to its surroundings effectively. Companies like Boston Dynamics (recently acquired by the tech giant Google) have developed biped robots like Atlas and Titan, which can walk on two legs like humans do. Similarly, Honda has developed a robot called Asimo, which is way ahead of the current generation of its kind of robots. Boston Dynamics has also developed a robot called Big Dog, which can climb complex mountain terrains successfully and jump over rocks like normal four legged animals do. Although legged mechanism has high mobility for rough terrain, the mechanism is complex and needs greater energy for walking. Hence a lot of advancement has been made, but still there are a few gaps to be filled to bring it to practical use.
Wheeled Robots are most commonly selected for traversing on continuous surfaces including rough terrain. For an exploration rover, wheel mechanisms are mainly used because of its stability, maneuverability and its simplicity to be controlled. Generally, four wheels are mounted at every leg tip, and the leg mechanism used is quite simple. Most of wheeled robot can’t get over discontinuous terrain, however, that is usually the best solution for continuous terrain. The main characteristics that a mobile robot uses for general purposes in rough terrain should possess are good ability to move on rough terrain, high-speed mobility, easy control and simplicity of mechanism. The legged robots are simpler in terms of structure but at the same time have limited moblility. They can be used in places with simpler obstacles that they can overcome easily and also their wheels need to avoid slippage while transporting the robot. Similarly, robots with treads (similar to those used in tanks) can provide a very effective solution for rough terrains motion except the control over treads is limited by their design. Considering these limitations, the concept of hybrid locomotion, where the legged wheels are used, comes into the scenario. These hybrid locomotion provides combined advantages of legged and wheeled robots, making it capable of passing unusual obstacles with a higher speed at the same time. Such robots are mainly used for explorations. One of the brilliant examples of such robots is the Mars rover, appropriate for extra-terrestrial activities.
The robot movement in rough terrain are required in a lot of applications, ranging from movement in internal pipelines to space explorations. The field in which such robots are mainly required is military. Operations like passing through hills, unsafe military combats and curfew zones require such skilled machines. Robots loaded with armor can be pretty helpful. Robots, like those from Boston Dynamics can be pretty helpful in such situations. Similarly, robots for medical assistance on military grounds can prove to be an excellent application for them. They can carry the injured militants to the base camps or aid the soldier onsite. Radioactive sites, where humans cannot be exposed to harmful radiation, can take use of such machines pretty well. To check up on the radiation leakage, to perform a land surveillance on a radiation affected area and to analyze a post-disaster scenario, robots can be extremely helpful. Similarly, to save people after landslides and Avalanche and analyze the situation after the disaster, robots for rough terrain can work well. In Mining and construction areas, these machine can find a pretty diverse application in terms of transporting material as well as taking actions during and after a disaster. Medical applications can also benefit from such development, like helping the disabled to move independently and helping the dyslexics. A pretty good example is a French robot called Nova. As stated above using the example of Mars Rover, robots for rough terrains can pretty well be used for space explorations. Though they may encounter an extremely rough terrain, robots can work well in such situations. A smart home is a new concept that has been pursued since long, where a who house can be accessed with the help of a robot who can perform all the domestic functions and keep the surrounding organized as been programmed or asked to.
With advancements in technology and the governing algorithms, the robots can behave more interactively with its environment. The current generation of robots have over ten thousand times higher processing speed and ten times more mobility than the first modern robot. With the advent of artificial intelligence with concepts like machine learning, a robot can learn from it surroundings on its own and perform functions accordingly. At University of Pennsylvania, scientists have developed a robot that can crawl like a snake, with very high mobility in inaccessible areas and is capable of climbing vertical surface like trees. New products like google self-driving cars also promote the use of their technology in modern robots for rough terrain applications. With such a high rate of advancement, soon robots will be able to perform any human or inhuman task possible.