ER4706 Applied Instrumentation: Crane LMI System Analysis Report

This report provides a detailed analysis of Load Moment Indicator (LMI) systems used in cranes. It begins with an overview of LMI systems, explaining their function in measuring load and preventing structural failures. The report then details various sensor systems within the LMI, including angle sensors, angle and length transmitters, wind speed sensors, load plate systems, and anti-two block (A2B) sensors. A significant portion of the report is dedicated to experimental critical analysis, comparing the performance of NI DAQ and NI LabVIEW software in analyzing sensor data, particularly for the A2B and wind speed sensors. The report concludes with an evaluation of signal conditioning elements and suggests directions for future development, such as cost reduction through modern sensor design and the integration of technologies like the Internet of Things (IoT). The report emphasizes the importance of accurate data analysis for crane safety and efficiency.

CRANE LMI SYSTEM FOR GLOBAL TECHNOLOGIES
Student Name
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Table of Contents
LMI SYSTEM OVERVIEW....................................................................................................................1
LMI SYSTEMS IN CRANES...................................................................................................................2
Angle sensor system...............................................................................................................................3
Angle and Length Transmitter system.................................................................................................3
Wind speed sensor system.....................................................................................................................3
Load plate system..................................................................................................................................4
Anti-two Block sensor system, A2B......................................................................................................4
A TYPICAL LMI DESIGN......................................................................................................................5
A MEASUREMENT SYSTEM BLOCK DIAGRAM............................................................................6
EXPERIMENTAL CRITICAL ANALYSIS...........................................................................................6
The Anti-Two Block Sensor System.....................................................................................................6
Wind Speed Sensor system...................................................................................................................7
SIGNAL CONDITIONING ELEMENTS EVALUATION...................................................................8
NEXT PHASE OF DEVELOPMENT.....................................................................................................8
CONCLUSION..........................................................................................................................................9
REFERENCES........................................................................................................................................10

LMI SYSTEM OVERVIEW
Hydraulic cranes are the kind of cranes that use the Load Moment Indicator. This Load Moment
Indicator is used in the cranes to read the load’s value of measurement using transducers. In their
operation, the transducers make use of pressure. Additionally, in cranes, they take readings on
the pressure of the lift’s cylinder. In cranes, the Load Moment Indicator helps to understand the
load lifting (Albinger, et al., 2017). With this same mechanism, the load operator is able to
understand the amount of load is lifted and if that load being lifted has exceeded. When the crane
is in operation therefore, the LMI measures the moment as well as the bearing force in the
crane’s arms.
During lifting, if the load being lifted gets beyond the limit that has been set, the crane will
automatically develop failures in various stages including structural as well as mechanical
failures. The crane operator is supposed to check closely the indication and functionality of the
LMI. This is because in the event that the load limit is about to exceed the set limit or has gone
beyond this limit, the system will give a signal to the operator (Bohnacker, et al., 2015). This in
return prevents the falling of the crane’s arm.
As part of calculation, there is inclusion of boom weight in the general crane load determination.
Effects like wind and ice usually affects the load’s general weight. The LMI system is meant
therefore to calculate the effects of these elements.

LMI SYSTEMS IN CRANES
The LMI system comprises of the Length transmitter as well as the Angle systems in cranes.
Other systems that are part of the LMI are the load plate system, Anti-two block, Angle and the
wind speed sensor systems.
Angle sensor system
The system is among the significant LMI systems. Through it, the position as well as the steering
wheel angle being used by an operator can be measured. The angle that the steering wheel turns
can also be rated by this system (Schneider, et al., 2011). This sensor has been fitted with tool for
scanning which helps to provide data on the degrees the wheel has been able to turn as well as its
position in general. In the steering column, there is a sensor cluster where this sensor is located.
A crane will always have two systems of this kind. This is for purposes of confirmation of data
as well as avoidance of redundancy of the data.
The two systems do not depend on each other at all. Further, each of them gives different data.
By analyzing the data from the two sensors, an operator is able to be sure about the operation.
Angle and Length Transmitter system
This system is part of LMI system of a crane. It is meant to take the measure of the cylinder and
the telescoping cylinder’s angle in comparison with the force of gravity. Every crane utilizes this
system because with it, the system can measure both the boom angle and the boom length (Fang,
et al., 2013). This system however cannot resist some surroundings and particularly in conditions
that are harsh. The sensor system may be removed for mobile cranes. In measuring the general
length, this system contains a cable reel that is estimated to be 32 feet. Also, it has a 30mm

resolution length, 0.2 degree accuracy angle, 0.2 degrees resolution angle and accuracy length of
about 30mm.
Wind speed sensor system
Any crane has been designed in a unique way that in places of unconducive environments like
places with very high wind speeds, it cannot function. This is deliberately done to ensure the
crane and its operator’s safety. This sensor system is then incorporated in cranes to measure and
determine that place’s safety before the operation as well as during the operation itself. During
times of high rates of wind, the sensor in the crane will signal the operator to take the required
measures. This wind speed sensor has a set limit. The sensor will determine if the limit has been
exceeded (Huang, et al., 2013). It will send the relevant signal to the operator on the dashboard.
The operator will then evaluate if it is safe to continue with the operation. If it is not, the
operation will have to be stopped.
Load plate system
The load plate is a space for loading where a load is at first placed before being transferred to
another vessel. This system is employed in cranes that are meant to load and offload loads that
are extremely heavy for example steel materials like plates, coils, tracks and ocean vessels
(Willim, Hans and Yggve, 2015).
The load plate should be able to develop a force that is so strong that it can handle an extra palate
meant to load wide loads or ships.
The system should also be able to manage wide leg used to offload and even load in each cycle
with no slewing.

Anti-two Block sensor system, A2B
This system is mainly employed to convey warnings to two block condition operator in a crane
(Ethington, B.G and Oshkosh, 2014). The lower hook of the crane being lifted until it touches the
crane boom hardware is what is called two-blocking condition. Sometimes, the lower and upper
parts of the pulley touches each other. The contact of the two parts is the origin of the term A2B.
The condition of two-blocking may occur when telescoping the boom out and when booming
down the crane. Whenever any of these happens, the crane’s lower hook will eventually draw
above the upper side of the sheave (Williams and Saker, 2019). This sensor system will then
prevent the crane’s hook block from crashing directly with the boom head. This is likely to
happen during load lifting. The counter weight is applied to ensure the contact switch remains
closed. This system will prevent the hook block from hitting the boom weight and instead hit the
counterweight. As a result, the counter weight will open the contact by rising and as such, the
switch needs to be of high reliability and be able to withstand all weather and climate conditions.
A TYPICAL LMI DESIGN

A MEASUREMENT SYSTEM BLOCK DIAGRAM
EXPERIMENTAL CRITICAL ANALYSIS
There is a requirement by the research that these sensor systems should be analyzed by NI
LabVIEW and DAQ software. This is done below.
The Anti-Two Block Sensor System
As already mentioned, this system prevents and warns the operator of a two block condition in
cranes. This critical condition rises from a situation where crane lower hook is lifted so high until
it touches the crane boom hardware (Kalairassan, Boopathi, and Mohan, 2017)

Using NI DAQ for the analysis, the results are that the boom weight as well as the hook block
are both monitored at about 15 inches. This is according to this analysis. This is a complete
opposite of the case when NI LabVIEW is applied. In this case, only 5 inches separates the hook
block from the boom weight, a distance that is so close and therefore dangerous in an event of a
mechanical malfunction or a simple mistake or system failure. If any of these happens, a crush
on the system’s upper side between the boom weight and the hook block will be experienced.
This possibility is proven by the fact that wind may sway off the load being lifted hence closing
that gap and eventually bringing the effect (Singh, et al., 2011)
Wind Speed Sensor system
In a normal situation, the design of any crane is that it cannot work in high wind speed places
(Hasan, et al., 2012). This guarantees the operator’s as well as the crane’s safety. This sensor is
therefore incorporated in the cranes to measure and evaluate the safety levels before operations
and during the operation as well. At any point when the speed of wind is quite high, the operator
will be in a position to get signals from the sensor for the required action to be taken. These
signals will be portrayed on the dashboard.
If NI DAQ software is used to analyze this critically, the sensor is able to take measurement on
the wind speed according to its intensity. This can be obtained from the load. Whenever the wind
speed is above 45km/h, this high speed will be detected by the sensor which will then suggest
that the crane operations be stopped immediately. With this software analysis therefore, the wind
speed limit that has been set is constant and cannot change even if there is changes in
temperature, which is likely to influence the wind’s intensity. When employing the NI LabVIEW
software during analysis, the wind speed is seen to be influenced by temperature as well as the
humidity present in the atmosphere (Zhou, et al., 2012). This results in a situation where the limit

of the wind speed could vary and range from 43km/h to 48km/hr. Using NI DAQ software in the
wind speed sensor analysis therefore proves to be sustainable and also has high levels of
accuracy for the operations of cranes.
SIGNAL CONDITIONING ELEMENTS EVALUATION
In the evaluation of LMI system, signal conditioning is quite crucial. This is because it provides
information on the system of measurement being employed in the LMI system of a crane (Chi, et
al., 2012). As seen in the following table, it is very crucial to study and understand the
conditioning of signals for all kinds of measurements.
NEXT PHASE OF DEVELOPMENT
A. Creating and expanding low cost systems as well as controllers.
Creation and expansion of the current LMI systems is very high in terms of cost, making a
crane’s total cost to be extremely high. Working towards design and development of modern
sensors as well as systems is significant (Koivumäki and Mattila, 2015). This is because it
will lower the general costs and make the systems affordable.

B. Instead of using the current mechanized ways of data transmission, usage of both wired
and wireless ways.
The current crane systems employ mechanized ways of data transmission to the
dashboard for the viewing by the operator. This is a slow way of transmitting information
compared to modern technologies (Fang, et al., 2016). The Introduction of the usage of
wireless as well as wired modes of transmission should be done to lower the general
system cost and also ensure faster conveyance of information to the intended users during
design and operation of cranes.
C. Utilizing the Internet of Things, IoT.
IoT is the most present day technology that is driving the whole world to new phases of
technology. With this technology, if introduced in the cranes, the dashboard could be kept
in the cloud. Later, this information can remotely be accessed at any time and from
anywhere (Hyla, 2012).
CONCLUSION
As already identified, for accurate and reliable results, the application of the NI DAQ software is
recommended rather than use of NI LabVIEW software for analysis. It is therefore advisable to
introduce the use of NI DAQ software in designing and developing LMI systems of cranes.
Further, to make the system more modern and cheaper, the latest technology should be
employed.

REFERENCES
Albinger, T.J., Taylor, J.W. and Nysse, B.N., Manitowoc Crane Companies Inc, 2017. System
and method for crane counterweight positioning. U.S. Patent 9,783,395.
Bohnacker, R., Kenzelmann, M. and Spaeth, H., Liebherr Werk Ehingen GmbH, 2015. Method
of monitoring crane safety during the setup procedure, as well as crane and crane control. U.S.
Patent 9,120,653.
Chi, H.L., Chen, Y.C., Kang, S.C. and Hsieh, S.H., 2012. Development of user interface for tele-
operated cranes. Advanced Engineering Informatics, 26(3), pp.641-652.
Ethington, B.G., Oshkosh Corp, 2014. Anti-two block system for a crane assembly. U.S. Patent
8,813,981.
Fang, Y., Cho, Y.K. and Chen, J., 2016. A framework for real-time pro-active safety assistance
for mobile crane lifting operations. Automation in Construction, 72, pp.367-379.
Fang, Y., Wang, P., Sun, N. and Zhang, Y., 2013. Dynamics analysis and nonlinear control of an
offshore boom crane. IEEE Transactions on Industrial Electronics, 61(1), pp.414-427.
Hasan, S., Zaman, H., Han, S., Al-Hussein, M. and Su, Y., 2012. Integrated building information
model to identify possible crane instability caused by strong winds. In Construction Research
Congress 2012: Construction Challenges in a Flat World (pp. 1281-1290).
Huang, J., Maleki, E. and Singhose, W., 2013. Dynamics and swing control of mobile boom
cranes subject to wind disturbances. IET Control Theory & Applications, 7(9), pp.1187-1195.
Hyla, P., 2012, August. The crane control systems: A survey. In 2012 17th International
Conference on Methods & Models in Automation & Robotics (MMAR) (pp. 505-509). IEEE.
Kalairassan, G., Boopathi, M. and Mohan, R.M., 2017, November. Analysis of load monitoring
system in hydraulic mobile cranes. In IOP Conference Series: Materials Science and
Engineering (Vol. 263, No. 6, p. 062045). IOP Publishing.
Koivumäki, J. and Mattila, J., 2015. High performance nonlinear motion/force controller design
for redundant hydraulic construction crane automation. Automation in Construction, 51, pp.59-
77.
Schneider, K., Sawodny, O. and Neupert, J., Liebherr Werk Nenzing GmbH, 2011. Crane
control, crane and method. U.S. Patent 8,025,167.
Singh, B., Nagar, B., Kadam, B.S. and Kumar, A., 2011. Modeling and finite element analysis of
crane boom. International Journal of Advanced Engineering Research and Studies, 1(1), pp.51-
55.
Williams, T. and Saker, T., Keppel Letourneau Usa Inc, 2019. Anti-two-block sensing systems.
U.S. Patent 10,233,058.