CONSTRUCTION EQUIPMENT MANAGEMENT NOTES 14

CHAPTER - 14

EQUIPMENT MANAGEMENT TIPS FOR THE CONSTRUCTION ENGINEERS 

AND PLANT & MACHINERY ENGINEERS

AN INTRODUCTION TO CONSTRUCTION PLANT AND EQUIPMENT

COMPUTERS IN CONSTRUCTION EQUIPMENT MANAGEMENT

1. Introduction

The application of computers in every field of life is now well known to everybody. Right from our school and colleges where we get our exam results, the salary we draw from office, we find computer is commonly used. The electric bill, telephone bills, and the bank account statements are some of the application in financial system. CAT scan or cardiology display monitor are some of the application in medical field. In fact use of computer screen has helped the doctor to save the lives of many serious patients. On home side especially in domestic appliances we find electronic mixer, electronic micro processor, washing machine, burglar alarm, smoke detector etc. In industry or space research computers have played a vital role. It is because of computer man could successfully conquer the space.

Whether this computer, a friend of so many, can be used on construction equipment which are subjected to rough use and varying weather conditions? The answer is yes. With the help of computer on construction equipment, one can :

i. Reduce fuel consumption of prime movers

ii. Achieve better production at economic cost

iii. Ensure safety and confidence in operation

iv. Help in maintenance

V. Give quality oriented production by electronic processing of ingredients especially in concreting and in compaction technology.

2. HISTORY

The oil crisis in 1970 forced companies around the world to go for small fuel efficient engines. The Japanese and U.S. manufacturer turned to electronic engine management for the answers, the technology had to provide.

i. High level of control

ii. Reliability under extreme conditions

iii. Highly accurate, very reliable sensor, and actuators.

iv. Malfunction diagnosis and servicing equipment and

v. Low cost of a level appropriate to use

At Toyota Automotive electronic begun in late 1950 when the first transistor radio was designed. In the year 1960, it made a policy to use electronic wherever possible. Electronic cruise control, automatic door lock, a semi-transistorized ignition system, LED illuminated dash boards were used. However it was the development of integrated circuits, which paved way for creation of sophisticated yet easy to use systems for 'complex process of cybernetic management of automobile'. In 1970, Toyota introduced first electronic controlled automatic transmission (FAT.) Then in 1970, it introduced an electronic fuel injection (EFI) that used IC.

Meanwhile, by 1971, Micro processor which had both memory and calculating utility, had been developed. General Motors U.S.A. became first company to use these Micro-computers on automobiles. It introduced MISAR, a micro-computerized Ignition control system in 1976.

In 1980, Toyota computer controlled system (TCCS) made its debut. Its computers controlled ignition volume, spark timing, and idling speed. It had a diagnostic system, since the Toyota introduced electronic instrument clusters, electronic controlled transmission (ECT). Toyota electronic modulated suspension (TEMS) and Toyota Electric Multi-vista with Cathode ray tube display.

The most interesting among these developments are diagnosis system, electric multi-vision, and electronic modulated suspension.

3. Application of nuclear electronic Technology on construction equipment;

Caterpillar pioneered the commercial application of modern electronic technology on construction equipment in 1978 when it introduced electronic monitoring system (EMS) now fitted virtually to all its earthmoving products.

Caterpillars is not, of course the only construction equipment. The other manufacturers and Komatsu Japan and Fiatallis Italy who have picked up GMS concept.

The impact of electronic and micro-processor technology is affecting three facts of equipment performance.

3.i Operating aids and controls, which improve the performance of individual vehicles, and their internal systems. Some, such as the electronic monitoring systems, merely provide the operator with additional or more easily understood information about how his machine is performing. Others, such as the Caterpillar automatic electronic traction aid(AETA), perform operational fine tuning required to meet specific ground or application conditions, without operator intervention.

3.ii Systems diagnostic and servicing aids, which pinpoint mechanical, electrical, and hydraulic faults, and can help anticipate future problems. The tools range from electronic and optical devices to simple gauges that measure component wear; associated with these are tools and systems and make it possible to repair components that might otherwise be junked.

3.iii. Management aids, which analyze operating data, some of which is already collected for machine monitoring, control or fault diagnoses. These aids analyze raw data that may reveal flaws in machine operating procedures, or different ways of handling jobs to reduce costs.

3.iv. Automatic Electronic traction Aid (AETA)

The AETA uses wheel speed sensors to monitor rear wheel rotation, and a microprocessor that compares this with the transmission output speed. When the microprocessor detects slip on either wheel, beyond a set limit to follow for the effects of cornering, it automatically brakes the spinning wheel. That allows the wheel on good ground to increase rim-pull, and so get the truck through a sticky patch.

The device addresses two serious flaws in current drive systems. a standard differential performs poorly on poor ground, because when one wheel begins to slip the torque on the other device axle is also reduced, regardless of whether or not it is on good footing. A limited slip, or No Spin, differential transfers torque to the wheel on better footing. It also impairs steering and can cause heavy stresses on power train components, shortening their life.

The AETA provides traction aid without incurring those disadvantages. Yet to create the device Caterpillar engineers had to find sensors that would accurately measure the input data, and develop the microprocessor circuitry to process the information and apply the brake when the spin was detected. They had to prove the component could take the mechanical stresses in the drive train, and that the complete system would function reliably...and that is there five years went.

The pay-off for customers who select the AETA option when buying rigid-frame dump trucks is not just improved safety, the result of unimpaired steering, or lower running costs, the result of reduced drive-line maintenance. It appears in the form of extended tyre life and reduced fuel consumption, simply because the vehicle spends less time spinning its wheels.

4. Control decisions:

Decisions must be made on how much control should be left in the hands of an operator, and how much should be transferred to the machine.

The approach is to give him aids that will make him more productive, to give him more sensors that will show how well he is doing. By giving him more aids, and a feeling for how the machine is performing, he can do a better job. As machines get larger and more complex, and the operator is isolated from the noise and vibration around him, we are replacing his own senses with sensors that are more accurate, and more reliable, than the ones he used to get through the seat of his pants.

5. MECHATRONICS

Mechatronics discipline combines both mechanics and electronics and is especially useful in robofees, automation and computer in integrated manufacturing through sophisticated software or Artificial intelligence does not fall under this discipline.

In 1979's it was used to describe a line of products that had many electronic components. It is but certainly a development of microprocessors opened new possibilities for controlling machine and the need of new name Machatronics.

Mechatronics will play an important role to produce more components that will be packaged and put into high precision and miniature devices.

6. Potential Proven

One microprocessor control system tested by Komatsu is already proven to eliminate most of the productivity differences between unskilled and experienced operators, while heavily reducing fuel consumption.

It works by the operator switching a control on the instrument panel to 'Learn', and manually running the machine through speed and blade height ranges while the on-board computer stores data on the ground conditions encountered. When switched to 'Control', the blade automatically raised and lowered to produce the most productive blade depth to tractive force ratio.

Unskilled operators became as productive as experienced operators, in most cases. And when an experienced operator was put on machines for some time before and after for comparisons use of the system increased productivity on a mid-size bulldozer by 13.6%, while fuel consumption declined 13%.

The outcome on the large-size machines was even more spectacular. Productivity increased 25% and fuel consumption was down 32%.

7. Application on Hydraulic Excavator

Advances in electronics and computers have added new flexibility to the design and operation of construction equipment, particularly hydraulic excavators. A vast range of control and monitoring systems and functions on already versatile machines, has opened up.

The technology allows excavator operators to make more efficient and effective use of engine and hydraulic power to boost production and reduce fuel consumption, while the constant microprocessor monitoring of machine systems and servicing requirements has contributed to improving equipment reliability and reduced maintenance.

Despite a slow start most of the world's hydraulic excavator manufacturers are now taking full advantage of the possibilities offered by electronics to provide an increasingly wide spectrum of new functions and controls. However the construction industry is generally very slow to accept new ideas and gimmicks' preferring to stick with established machines, systems and work practices. Particularly in Europe, there has been a comparatively slow response to the expanding technology. But in Japan electronically equipped excavators have been enthusiastically welcomed. In a gadget oriented country it is not surprising that the philosophy has permeated Japan's construction equipment industry too.

Considerable emphasis on electronics, combined with computer technology has made a major contribution to Japanese plant manufacturers' ability to boost excavator performance over less sophisticated rivals, further increasing the versatility of these already multipurpose machines. Komatsu now supplies its excavators as standard with an electronically controlled digging mode selection system enabling suitably trained and skilled operators quickly and easily to 'tune' the machine on site for optimum digging power, speed and fuel economy. With the simple flick of switch on the machine's instrument panel the excavator driver can change the excavator operation to either light, standard of heavy duty operation to match the ground conditions. The control makes more efficient use of engine power by varying the torque applied to the excavator's variable displacement hydraulic pumps and contributes to improving fuel consumption. The heavy duty mode is used for high volume, fast digging and loading work. Engine speed is kept constant and power continuously monitored and controlled by the onboard microcomputer to enable the hydraulic pumps to use full engine power.

The electronic mode selection device together with what Komatsu calls its open center load sensing hydraulic system, which automatically reduces various types of hydraulic circuit losses, has combined to improve fuel consumption considerably over machines with basic hydraulic systems.

8. Data display cuts dump truck overload

Caterpillar's development of a sophisticated electronic payload monitor for giant dumptrucks demonstrates how manufacturers are responding to the heightened cost consciousness of their customers.

The device is an extremely expensive optional extra but Caterpillar is confident that the unit can quickly recover its capital outlay of over $10,000 by preventing damaging overloads.

Truck drivers in cabs and site or mine managers in offices will simultaneously be able to keep an accurate record of material transported each cycle or over different time scales and to spot any material in the truck body during the return journey. The equipment is designed to increase the life of expensive tyres and to reduce component wear, maintenance and machine downtime.

The device is so sensitive, claims Caterpillar, that it can even detect deterioration of haul roads. Data from the on board payload monitor's computer can be automatically transmitted to the main site office enabling constant scanning, if necessary, of an individual truck's availability, production and performance.

Dumptruck overloading and incorrect tyre pressures are major contributory factors to overall owning and operating costs. Tyre manufacturers have proved, under controlled tests substantiated by actual site operational data, which overloading a dumptruck by just 10% will result in a 15% reduction intyre lift. A 20% overload will reduce life by 30%.

Correct loading will also make an indeterminate contribution to reducing overall truck operating costs.

Data for the electronic watchdog is collected from pressure sensors mounted on the truck's nitrogenil suspension cylinders. Changes in gas pressure as the vehicle is loaded are analyzed by onboard computer and transferred as a digital read-out of actual load in the truck body to a display panel in the driver's cab. Caterpillar claims an accuracy of _+" 5% for each load or " +" 2% over a whole day.

Large red and green lights on each side of the struck indicate to the excavator operator when the correct load has been reached.

The truck driver can also punch into the display box other details including the vehicle's identity number, maximum loading weight and weighting units in American or metric tons within a range of 85% to 115% of the truck's rated carrying capacity.

All data from each truck can be transmitted to the main office for display on a screen or as hardcopy, to indicate truck type and number, loading start time, pay loads, loading times, haul and return times, load and empty travel distances, ratios of tons carried to kilometers traveled and empty travel distances.

9. Computerized Maintenance

Computerized maintenance programs are the latest weapon in the war against costly equipment downtime. Squeezed by escalating costs and increased competition. Construction contractors are doing away with cumbersome manual maintenance recording systems that were rarely adequate for the task. Computers are helping construction firms reduce equipment operating costs by controlling factors from downtime to parts inventory.

10. Reducing Breakdowns

A good computerized maintenance system will save a contractor money by analyzing statistics about operating data including fuel and lubricant consumption, filter replacement, wear part performance, and the timing of, and reason for, repairs. The information generated can show which machines are costing the most to run, or even point to operators who are harder on their equipment than others. Used in conjunction with other preventive maintenance tools, such as oil sampling and electronic diagnosis, it will help point to developing problems before they become major breakdowns.

The computer program will note how many hours are left on the engine, transmission, or tires; and, unlike the slower manual systems, the program can be used to quickly estimate the cost of a specific repair.

Additionally, the computer keeps track of equipment spread over various sites, and a record of how many hours each piece of equipment puts in at each site.

11. The future

Ignoring its diagnostic tools and related products. Caterpillar, already has 40 control and monitoring systems, four of which incorporate microprocessors, in or close to production. Dozens more are in various stages of concept, design, proving and testing.

Already vehicles are going out of the gates fitted with several of the devices. Dump trucks currently incorporate an electronic transmission control and the EMS box as standard; options include the AETA device, and fire control system. Only the EMS box is not microprocessor controlled.

The process of integrating the individual components has already begun 'It is an area we are going more and more into', said Hutable.

"We are tying things together so that a transmission control will be influenced by what is happening in the engine, and vice versa. We are already doing some of that in locomotive applications to optimize potential efficiency. You get better fuel economy, and by making sure the right gear is being used at different speed settings, you reduce wear and tear on the whole system".

Currently "moving toward production" is a generator package that includes a computerized system for monitoring various engine operations and power output parameters, mainly for production purposes.

The next stage of the integration process involves taking the information already being collected by sensors and microprocessors from the vehicle for further analysis. Storing the operating data in computer memory chips creates a detailed operating history that does not rely on operators and servicemen keeping accurate, manual records.. the step on which the best of plant management plans often falters.

At intervals, the stored operating data is collected in acquisition units, and transferred to remote computer systems for further analysis. At that point the information obtained primarily to improve a machine's efficiency becomes available to the fleet owner in almost any form he wants it.

It makes possible the creation of machine operating histories for more detailed and accurate than anything currently available. It will report potentially damaging events, such as over speeding or over temperature warnings that an operator may not notice, or might deliberately choose to conceal; knowing those events occurred will give servicemen an idea of what to look for during regular inspections, or provide clues to the cause of a mechanical problem.

These programs will take performance data not previously available and come up with meaningful interpretations for the vehicle owner", said Marwood.

Already, highway truck trip record systems can perform some of these functions. One large US trucking firm pays its drivers a bonus when they do not exceed 90 Km/h on a journey; the driver is penalized for exceeding 96 km/h for more than 1.6 km in 160 km, and can be fired if he does it more than three times.

The information makes owners more aware of what is happening to their equipment, so they can manage it better.

The data has further uses. One major problem confronting contractors wishing to computerize their equipment fleet management is that basic information must still be collected manually, a task dependent on operators and service personnel usually reluctant to fill in their own time sheets, let alone other pieces of paper. Now that the data is available directly from the computer memory chips, installed on the machine or its individual components, it appears the next logical step would be software to process management records and integrate them with accounting.

That then, is the vision. Equipment that uses data won from its own system to help its operator produce more, let its servicemen repair it more quickly, and make its owner make more money.

Despite its complexity, none of the components of the vision are beyond the reach of modern engineering and computer science. Most already exist in modification required to ensure their survival in the construction equipment environment. The future, the vision, is near.