TYPES OF HOISTSAND

MATERIAL HANDLING THROUGH ROBOTICS

BY:- ATIYA JAMAL

ANJALI TIWARI ARPITA NAYYAR DEEPA KHIYANI

CHACHAL THAWANI

Hoist (device)

A hoist is a device used for lifting or lowering a load by means of a drum or lift-wheel around which rope or chain wraps. It may be manually operated, electrically or pneumatically driven and may use chain, fibre or wire rope as its lifting medium. The load is attached to the hoist by means of a lifting hook.

TYPES OF HOISTS

The basic hoist has two important characteristics to define it: Lifting medium and power type. The lifting medium is either wire rope, wrapped around a drum, or load-chain, raised by a pulley with a special profile to engage the chain. The power can be provided by different means. Common means are hydraulics, electrical and air driven motors. Both the wire rope hoist and chain hoist have been in common use since the 1800s. however; Mass production of an electric hoist did not start until the early 1900's and was first adapted by Germany. A hoist can be built as one integral-package unit, designed for cost-effective purchasing and moderate use, or it can be built as a built-up custom unit, designed for durability and performance.

The built-up hoist will be much more expensive, but will also be easier to repair and more durable. Package units where once regarded as being designed for light to moderate usage, but since the 60's this has changed. Built-up units are designed for heavy to severe service, but over the years that market has decreased in size since the advent of the more durable packaged hoist. A machine shop or fabricating shop will use an integral-package hoist, while a Steel Mill or NASA would use a built-up unit to meet durability, performance, and reparability requirements. NASA has also seen a change in the use of package hoists. The NASA Astronaut training pool for example utilizes cranes

with packaged hoists.

Wire rope hoist or chain hoist

Common small portable hoists are of two main types, the chain hoist or chain block and the wire rope or cable type. Chain hoists may have a lever to actuate the hoist or have a loop of operating chain that one pulls through the block (known traditionally as a chain fall) which then activates the block to take up the main lifting chain.

Fig.1 Builders hoist with small gasoline engine.

A ratchet lever hoist (come-a-long)

Ratchet lever hoists have the advantage that they can usually be operated in any orientation, for pulling, lifting or binding. Chain block type hoists are usually suitable only for vertical lifting . For a given rated load wire rope is lighter in weight per unit length but overall length is limited by the drum diameter that the cable must be wound onto. The lift chain of a chain hoist is far larger than the lift wheel over which chain may function. Therefore, a high-performance chain hoist may be of significantly smaller physical size than a wire rope hoist rated at the same working load.

Hoist controller

A hoist controller is the controller for a hoist. The term is used primarily in the context of electrically operated hoists, but it is apparent that the control systems of many 20th century steam hoists also incorporated controllers of significant complexity. Consider the control system of the Quincy Mine No. 2 Hoist. This control system included interlocks to close the throttle valve at the end of trip and to prevent opening the throttle again until the winding engine was reversed. The control system also incorporated a governor to control the speed of the hoist and indicator wheels to show the hoist operator the positions of the skips in the mine shaft.

The hoist controllers for modern electric mining hoists have long included such features as automatic starting of the hoist when the weight of coal or ore in the skip reaches a set point, automatic acceleration of the hoist to full speed and automatic deceleration at the end of travel. Hoist controllers need both velocity and absolute position references taken, typically taken from the winding drum of the hoist.  Modern hoist controllers replace many of the mechanical analog mechanisms of earlier controllers with digital control systems.

Hydraulic hooklift hoist

Hydraulic hook lift hoists are mounted on heavy duty trucks to enable hauliers to change out flatbeds, dumpster bodies, and similar containers. Primarily used in conjunction with tilt frame bodies and specialised containers, generally designed for the transportation of materials in the waste, recycling, scrap and demolition industries.

The system employs a series of hydraulic rams to hook, lift and hoist the container onto the chassis of the truck. There are several configuration options, and strict guidelines which must be followed to ensure that the container is secured on the truck in transit.

Red trash can.

Typical hook lift hoist (single lift/dump cylinder configuration)

25 Ton Hook lift hoist (dual lift/dump cylinder) mid lift

Lift/dump cylinder(s)Two configurations are typical, both suitable for either single or dual pivot designs.The single lift dump cylinder design reduces unit cost, retains true hook lift capabilities, but can be unstable while dumping on uneven ground.The dual lift/dump cylinder design, whilst increasing unit cost, improves load handling stability when dumping on uneven ground.

Examples of hoists

Single-drum hoist Double-drum hoist Friction (Koepe) hoist

Blair-multi rope hoist Conical drum Spiral drum

Advantages

a) The flexibility offered by the hydraulic hook lift hoist system offers several advantages:

b) Reduced licensing fees through reduced fleet size

c) Ground level loading and unloading

d) Exact positioning (dropping off) of containers

e) Ability to get in and out of tight spaces

f) Quick exchange of containers: system allows container to be lift/dropped in around 90 seconds

g) Ability to engage a container up to 30° off centre when picking up

h) No cables to hook up, unhook or that could potentially break

i) Complete in-cab operation

Disadvantages

a) The main disadvantages of the system are revealed on uneven ground:

b) If below grade reach is small, it can be difficult to set down or pick up container

c) Load handling stability, particularly while dumping, can be compromised at maximum dump angle. This is particularly the case in single lift/dump cylinder configurations

d) Container lengths are fairly inflexible, as hook lift hoists are designed to carry bodies within 3 to 5 ft (914 to 1,524 mm) of the shortest recommended body

ROBOTICS

Robotics

Robotics is the branch of technology that deals with the design, construction, operation and application of robots and computer systems for their control, sensory feedback, and information processing. These technologies deal with automated machines that can take the place of humans, in hazardous or manufacturing processes, or simply just resemble humans. Many of today's

robots are inspired by nature contributing to the field of bio-inspired robotics .The concept and creation of machines that could operate autonomously dates back to classical times, but research into the functionality and potential uses of robots did not grow substantially until the 20th century. Throughout history, robotics has been often seen to mimic human behaviour, and often manage tasks in a similar fashion. Today, robotics is a rapidly growing field, as we continue to research, design, and build new robots that serve various practical purposes, whether domestically, commercially, or militarily. Many robots do jobs that are hazardous to people such as defusing bombs, exploring shipwrecks, and mines.

Etymology

The word robotics was derived from the word robot, which was introduced to the public by Czech writer Karle Čapekin his play R.U.R. (Rossum's Universal Robots), which premiered in 1921. The word robot comes from the Slavic word robot, which is used to refer forced labour.According to the Oxford English Dictionary, the word robotics was first used in the print by Isaac Asimov, in his science fiction short story "Liar!", published in May 1941 in Astounding Science Fiction. Asimov was unaware that he was coining the term; since the science and technology of electrical devices is electronics, he assumed robotics already referred to the science and technology of robots. In some of Asimov's other works, he states that the first use of the word robotics was in his short story Runaround (Astounding Science Fiction, March 1942).[4][5] However, the original publication of "Liar!" predates that of "Runaround" by five months, so the former is generally cited as the word's origin.

Components:a) Power source

At present mostly (lead-acid) batteries are used as a power source. Many different types of batteries can be used as a power source for robots. They range from lead acid batteries which are safe and have relatively long shelf lives but are rather heavy to silver cadmium batteries that are much smaller in volume and are currently much more expensive. Designing a battery powered robot needs to take into account factors such as safety, cycle lifetime and weight. Generators, often some type of internal combustion engine, can also be used. However, such designs are often mechanically complex and need fuel, require heat dissipation and are relatively heavy. A tether connecting the robot to a power supply would remove the power supply from the robot entirely. This has the advantage of saving weight and space by moving all power generation and storage components elsewhere. However, this design does come with the drawback of constantly having a cable connected to the robot, which can be difficult to manage.

Potential power sources could be:

Pneumatic (compressed gases)Hydraulics (liquids)flywheel energy storageorganic garbage (through anaerobic digestion)faeces (human, animal); may be interesting in a military context as faeces of small combat groups may be reused for the energy requirements of the robot assistant (see DEKA's project Slingshot Stirling engine on how the system would operate)

b) Actuation

Actuators are like the "muscles" of a robot, the parts which convert stored energy into movement. By far the most popular actuators are electric motors that spin a wheel or gear, and linear actuators that control industrial robots in factories. But there are some recent advances in alternative types of actuators, powered by electricity, chemicals, or compressed air.

c) Electric motorsThe vast majority of robots use electric motors, often brushed and brushless DC motors in portable robots or AC motors in industrial robots and CNC machines. These motors are often preferred in systems with lighter loads, and where the predominant form of motion is rotational.

d) Linear actuators Various types of linear actuators move in and out instead of by spinning, and often have quicker direction changes, particularly when very large forces are needed such as with industrial robotics. They are typically powered by compressed air (pneumatic actuator) or an oil (hydraulic actuator).

e) Series elastic actuators

A spring can be designed as part of the motor actuator, to allow improved force control. It has been used in various robots, particularly walking humanoid robots.

f ) air muscles

Pneumatic artificial muscles, also known as air muscles, are special tubes that contract (typically up to 40%) when air is forced inside them. They have been used for some robot applications.[16][17]

g) Muscle wire

Muscle wire, also known as Shape Memory Alloy, Nitinol or Flexinol Wire, is a material that contracts slightly (typically under 5%) when electricity runs through it. They have been used for some small robot applications

h) Electroactive polymers

EAPs or EPAMs are a new plastic material that can contract substantially (up to 380% activation strain) from electricity, and have been used in facial muscles and arms of humanoid robots,[20] and to allow new robots to float,[21] fly, swim or walk.[22]

i) Piezo motorsRecent alternatives to DC motors are piezo motors or ultrasonic motors. These work on a fundamentally different principle, whereby tiny piezoceramic elements, vibrating many thousands of times per second, cause linear or rotary motion. There are different mechanisms of operation; one type uses the vibration of the piezo elements to walk the motor in a circle or a straight line.[23] Another type uses the piezo elements to cause a nut to vibrate and drive a screw. The advantages of these motors are nanometre resolution, speed, and available force for their size. These motors are already available commercially, and being used on some robots

j) Elastic nanotubes

Elastic nanotubes are a promising artificial muscle technology in early-stage experimental development. The absence of defects in carbon nanotubes enables these filaments to deform elastically by several percent, with energy storage levels of perhaps 10 J/cm3 for metal nanotubes. Human biceps could be replaced with an 8 mm diameter wire of this material. Such compact "muscle" might allow future robots to outrun and out jump humans.

k) Sensing

Sensors allow robots to receive information about a certain measurement of the environment, or internal components. This is essential for robots to perform their tasks, and act upon any changes in the environment to calculate the appropriate response. They are used for various forms of measurements, to give the robots warnings about safety or malfunctions, and to provide real time information of the task it is performing.

l) TouchCurrent robotic and prosthetic hands receive far less tactile information than the human hand. Recent research has developed a tactile sensor array that mimics the mechanical properties and touch receptors of human fingertips. The sensor array is constructed as a rigid core surrounded by conductive fluid contained by an elastomeric skin. Electrodes are mounted on the surface of the rigid core and are connected to an impedance-measuring device within the core. When the artificial skin touches an object the fluid path around the electrodes is deformed, producing impedance changes that map the forces received from the object. The researchers expect that an important function of such artificial fingertips will be adjusting robotic grip on held objects.Scientists from several European countries and Israel developed a prosthetic hand in 2009, called Smart Hand, which functions like a real one—allowing patients to write with it, type on a keyboard, play piano and perform other fine movements. The prosthesis has sensors which enable the patient to sense real feeling in its fingertips

m) VisionComputer vision is the science and technology of machines that see. As a scientific discipline, computer vision is concerned with the theory behind artificial systems that extract information from images. The image data can take many forms, such as video sequences and views from cameras.In most practical computer vision applications, the computers are pre-programmed to solve a particular task, but methods based on learning are now becoming increasingly common.Computer vision systems rely on image sensors which detect electromagnetic radiation which is typically in the form of either visible light orinfra-red light. The sensors are designed using solid-state physics. The process by which light propagates and reflects off surfaces is explained using optics. Sophisticated image sensors even require quantum mechanics to provide a complete understanding of the image formation process. Robots can also be equipped with multiple vision sensors to be better able to compute the sense of depth in the environment. Like human eyes, robots' "eyes" must also be able to focus on a particular area of interest, and also adjust to variations in light intensities.There is a subfield within computer vision where artificial systems are designed to mimic the processing and behaviour of biological systems, at different levels of complexity. Also, some of the learning-based methods developed within computer vision have their background in biology

Manipulation

Robots need to manipulate objects; pick up, modify, destroy, or otherwise have an effect. Thus the "hands" of a robot are often referred to as end effectors, while the "arm" is referred to as manipulator.Most robot arms have replaceable effectors, each allowing them to perform some small range of tasks. Some have a fixed manipulator which cannot be replaced, while a few have one very general purpose manipulator, for example a humanoid hand.For the definitive guide to all forms of robot end-effectors, their design, and usage consult the book "Robot Grippers".[33]

Rolling robots

For simplicity most mobile robots have four wheels or a number of continuous tracks. Some researchers have tried to create more complex wheeled robots with only one or two wheels. These can have certain advantages such as greater efficiency and reduced parts, as well as allowing a robot to navigate in confined places that a four wheeled robot would not be able to.

Two-wheeled balancing robots

A one-wheeled balancing robot is an extension of a two-wheeled balancing robot so that it can move in any 2D direction using a round ball as its only wheel. Several one-wheeled balancing robots have been designed recently, such as Carnegie Mellon University's "Ballbot" that is the approximate height and width of a person, and Tohoku Gakuin University's "BallIP".[45]

 Because of the long, thin shape and ability to maneuver in tight spaces, they have the potential to function better than other robots in environments with people.[46]

Tracked robots

Tank tracks provide even more traction than a six-wheeled robot. Tracked wheels behave as if they were made of hundreds of wheels, therefore are very common for outdoor and military robots, where the robot must drive on very rough terrain. However, they are difficult to use indoors such as on carpets and smooth floors. Examples include NASA's Urban Robot "Urbie"

Walking applied to robotsWalking is a difficult and dynamic problem to solve. Several robots have been made which can walk reliably on two legs, however none have yet been made which are as robust as a human. There has been much study on human inspired walking, such as AMBER lab which was established in 2008 by the Mechanical Engineering Department at Texas A&M University.Many other robots have been built that walk on more than two legs, due to these robots being significantly easier to construct. Walking robots can be used for uneven terrains, which would provide better mobility and energy efficiency than other locomotion methods. Hybrids too have been proposed in movies such as I, Robot, where they walk on 2 legs and switch to 4 (arms+legs) when going to a sprint. Typically, robots on 2 legs can walk well on flat floors and can occasionally walk up stairs. None can walk over rocky, uneven terrain. Some of the methods which have been tried are:

a) ZMP Technique

The Zero Moment Point (ZMP) is the algorithm used by robots such as Honda's ASIMO. The robot's onboard computer tries to keep the total inertial forces (the combination of earth's gravity and the acceleration and deceleration of walking), exactly opposed by the floor reaction force (the force of the floor pushing back on the robot's foot). In this way, the two forces cancel out, leaving no moment (force causing the robot to rotate and fall over). However, this is not exactly how a human walks, and the difference is obvious to human observers, some of whom have pointed out that ASIMO walks as if it needs the lavatory. ASIMO's walking algorithm is not static, and some dynamic balancing is used (see below). However, it still requires a smooth surface to walk on.

b) HoppingSeveral robots, built in the 1980s by Marc Raibert at the MIT Leg Laboratory, successfully demonstrated very dynamic walking. Initially, a robot with only one leg, and a very small foot, could stay upright simply by hopping. The movement is the same as that of a person on a pogo stick. As the robot falls to one side, it would jump slightly in that direction, in order to catch itself. Soon, the algorithm was generalised to two and four legs. A bipedal robot was demonstrated running and even performing somersaults .A quadruped was also demonstrated which could trot, run, pace, and bound. For a full list of these robots, see the MIT Leg Lab Robots page.

c) Dynamic balancing (controlled falling)

A more advanced way for a robot to walk is by using a dynamic balancing algorithm, which is potentially more robust than the Zero Moment Point technique, as it constantly monitors the robot's motion, and places the feet in order to maintain stability. This technique was recently demonstrated by Any bots' Dexter Robot,[66] which is so stable, it can even jump. Another example is the TU Delft Flame.

d) Passive dynamics

Perhaps the most promising approach utilizes passive dynamics where the momentum of swinging limbs is used for greater efficiency. It has been shown that totally unpowered humanoid mechanisms can walk down a gentle slope, using only gravity to propel themselves. Using this technique, a robot need only supply a small amount of motor power to walk along a flat surface or a little more to walk up a hill. This technique promises to make walking robots at least ten times more efficient than ZMP walkers, like ASIMO

Modern robot*Mobile Robot

Mobile robots have the capability to move around in their environment and are not fixed to one physical location. An example of a mobile robot that is in common use today is the automated guided vehicle or automatic guided vehicle (AGV). An AGV is a mobile robot that follows markers or wires in the floor, or uses vision or lasers. AGVs are discussed later in this article.Mobile robots are also found in industry, military and security environments. They also appear as consumer products, for entertainment or to perform certain tasks like vacuum cleaning. Mobile robots are the focus of a great deal of current research and almost every major university has one or more labs that focus on mobile robot research.Modern robots are usually used in tightly controlled environments such as on assembly lines because they have difficulty responding to unexpected interference. Because of this most humans rarely encounter robots. However domestic robots for cleaning and maintenance are increasingly common in and around homes in developed countries. Robots can also be found in military applications

Industrial robots (manipulating)

Industrial robots usually consist of a jointed arm (multi-linked manipulator) and an end effecter that is attached to a fixed surface. One of the most common type of end effecter is a gripper assembly.The International Organization for Standardization gives a definition of a manipulating industrial robot in ISO 8373:"an automatically controlled, reprogrammable, multipurpose, manipulator programmable in three or more axes, which may be either fixed in place or mobile for use in industrial automation applications."[42]

This definition is used by the International Federation of Robotics, the European Robotics Research Network (EURON) and many national standards committees.[43]

Service robot

Most commonly industrial robots are fixed robotic arms and manipulators used primarily for production and distribution of goods. The term "service robot" is less well-defined. IFR has proposed a tentative definition, "A service robot is a robot which operates semi- or fully autonomously to perform services useful to the well-being of humans and equipment, excluding manufacturing operations.

Healthcare

Robots in healthcare have two main functions. Those which assist an individual, such as a sufferer of a disease like Multiple Sclerosis, and those which aid in the overall systems such as pharmacies and hospitals.

The Care-Providing Robot FRIEND. 

Industrial Robotics.flv

Toblerone Chocolate Robotic Material Handling with ABB Robot-1.mp4

Videos on material handling by robotics

Reference

Google Wikipedia Text book on material handling U – tube