Fluid Power Research Centres Around The World

The official birth of the Institute for agricultural andearthmoving machines (IMAMOTER) falls in 2002 but it inherits the work of two previous Institutes: the Institute for earthmoving machines and off-road vehicles (CEMOTER) and the Institute for agricultural mechanization
(IMA). The background story, in brief, is the
following:

The CEMOTER Institute started (with a different name) in the mid sixties as a Centre of the National Research Council located in the Polytechnic Instituteof Turin, where it stayed until 1981. Then it moved to Ferrara and became an independent Institute, with the partial support of external parties (among them the Municipality of Ferrara and the National Association of Earthmoving Machine Manufacturers, i.e. UNACOMA COMAMOTER);

The IMA Institute started (with a different name) in the early fifties in Torino as an Institute of the National Research Council, with the cooperation of external parties (among them the Municipality of Torino, the University of Torino, and the FIAT company), and underwent successive development stages and expansions. In the late eighties the basic location of the Institute moved to the newly built Research Area of Torino.

The mission of IMAMOTER-CNR can be described in two ways. Firstly, the official statement of the bylaws which contain a quantitative description, i.e. a list of
eight fields of activity:

innovation of fluid power components and systems
unstructured robotics and mechatronics
numerical and experimental analysis of structures and fluid fields
monitoring and control of noise emission from complex sources
analysis and reduction of vibrations and structural noise
design of machines and their subsystems
mechanization of cultures and its environmental impact
certification, standardization and testing of agricultural and earthmoving machines.

The second description is, in a certain sense, qualitative, and aims at expressing the general perspective or attitude which drives the specific activities and actions of the Institute. From this point of view the mission can be stated as the goal of being a recognized reference point in both an academic and an industrial sense, able to promote and disseminate knowledge in key areas which are primarily (but not exclusively) relevant to agricultural and earthmoving machines.

Research Activities

Fluid Power and Control Systems

The objective is to contribute, by means of the more advanced techniques applied in fluid power design, to the advancement of knowledge and experience supporting design and operation of earthmoving, construction and agricultural machines. The mobile applications are the main target of our activities with special emphasis on fluid power transmissions and control systems. Figures 1 and 2 show two examples of studies performed to improve the efficiency of fluid power circuits in mobile applications. The first one is a study of the flow forces, using a CFD simulation software, by which anoptimization of a spoil valve was performed.

Fig. 1: Example of a CFD study performed at IMAMOTER- CNR

The second one is a predictive analysis of the capacity and the leakage of a shaft in an agricultural machine transmission. Both these works, performed for two different industries, have as objective the reduction of power loss and the improvement of performance in the hydraulic circuit.

Fig. 2: CFD analysis of transmission shaft capacity and leakage

Computational fluid dynamic is intensively used in IMAMOTER-CNR to have a precise description of internal flow; while non-linear dynamic simulation is used to describe the system interaction and to develop new control strategies. The electronic control is a must. IMAMOTER-CNR can plan and prototype electronic hardware and software for electronic control units compliant with new safety standards: ISO25119 for agricultural machines, ISO15998 for earthmoving machines and ISO 26262 for the automotive environment. Hydrostatic transmission electronic control systems are not neglected: we have more than seven years experience in electronic control units for hydrostatic transmission control, hardware design, embedded software design and control strategies design and calibration, both on test rigs and on real machines. Backhoe loaders, special machines and front loaders have been built and tested byour researchers in the last seven years.

Fig. 3: Evaluation of electronic parameters in an hydrostatic control unit

The new activities in the field of hydrostatic transmissions are: power control, machine control system integration by CAN Network, and safety of electronic components following the IEC 61508 international standard. CAN Networks, SAE J 1939 for powertrain network, ISOBUS (ISO 11783) for agricultural machines
automation have been designed. Furthermore, agricultural applications (Class 3 tractor ECU, sprayers, seeders, lawnmowers and special units for harvester machines) have been developed.

Fig. 4: Electronic Load sensing control systems

IMAMOTER-CNR can claim competences in electronic load sensing control systems. Two projects have been developed with a completely different approach:
the first one designed as an add-on to existing systems, the second one with high mechatronic integration of electronic and hydraulic components. Torque control,
power control, anti-stall control and variable load sensing have been introduced in both types of hydraulic system topology, with machine control system integration
by the CAN network. Both system topology and electronic systems have been designed and realized and a new electronic control unit have been designed with a
DSP controller with task control at 100 microseconds cycle time. Studies on the best power control methodology for the proportional coil were investigated and
more than one product has been designed. A new approach to valve control system was investigated, with high speed DPS and a new generation of calibration
system, via CAN network, with oscilloscope functions in order to calibrate and test control system parameters. High level performances have been reached and new
products are still under development; three configurations are being implemented: current closed loop, spool position closed loop and actuator position, and velocity
closed loop.
Other areas in which IMAMOTER-CNR is engaged are: the complete qualification of pump, directional and proportional valves; the design of dedicated test circuit and acquisition systems; the study and application of more relevant virtual prototyping technologies and simulation analysis; and the basic research to improve
the numerical method used in fluid power design. Thanks to availability of test rings up to 170 kW, we are able to plan highly flexible and completely automated
work cycles, with direct acquisition data (i.e. by means of LabView).

Fig. 5: Acquisition test rig used for flow dividers

Research in fluid power yielded valuable results both in terms of new component design, and new circuital arrangement, as the following examples show.

Fig. 6: The ARM valve

The first one presents a new concept of a hydraulic valve that tries to overcome a well-known problem affecting the pilot operated proportional valves, the flow
forces. Trying to design a low-flow-forces valve, a new valve was conceived, named Proportional Valve with Axial Flow and Rotational Metering (ARM), and patented as Patent IT TO2007A000518. Despite the traditional compensated profile spool valves, the basic idea is to design a valve that has as few mobile surfaces as possible. This assumption modifies the traditional valve design method and opens up new possibilities for the proportional valves. The basic idea is to meter the pass through regulating two areas. The size of these areas is ruled by the relative rotation between two components (a stator and a rotor) shaped in order to commute from the “fully closed” position to the “fully open” through a relative rotation of a given angle φ. Pilot pressures and possible springs act on an element called a reducer. Its position rules the angular displacement between the stator and the rotor. This valve is almost insensitive to flow forces and allows an axial fluid flow. This latter aspect makes the component particularly suited to cartridge design.
The second innovation recently proposed by the Institute for Agricultural and Earth Moving Machines is a novel system design of fluid power systems which improves the control and energy use for multiple actuator systems with particular focus on mobile applications such excavators, loaders, tractors. The system is based
on a new patented technology (Patent ITTO2007A000516): the “Load Sensing with Active Regeneration System”. The main idea is to overcome one of the main drawbacks of multiple actuators conventional Load Sensing Systems: while the higher actuator load drives the pump delivery pressure the other active actuators are controlled by the local compensators in a dissipative mode. The goal of the novel architecture is to actively use pressure drops usually wasted in the local compensators and, in case of assistive or overrunning loads, dissipated over control valves.

Fig. 7: The ARLS architecture

The Active Regeneration Load Sensing System (ARLS) combines the benefits of the parallel architecture and the series architecture, as it can work as a parallel
Load Sensing System, but can also connect in series the actuators or crate a hybrid pattern in which an Actuator is fed both by the supply and by a Second Actuator
Outflow. The ARLS systems introduce an important reduction of energy loss as the following figure shows.

Fig. 8: ARLS Architecture energy map

Fig. 9: Innovative manifold prototype, realized in FRP

A new sector in which IMAMOTER-CNR is putting a lot of research efforts is the area of new material. We are studying the applicability and the performance
of unconventional material (fibre reinforced plastic, composites, ceramics, etc.) in fluid power systems. Our work is currently focused on the introduction of polymeric material in the operator protective structures and the use of reinforced plastics and composite materials to manufacture fluid power circuit components. We try to introduce the “new material” culture into the fluid power world.

This innovation requires the use of new design paradigms to consider the unusual characteristics of these, always complex, materials (e.g. anisotropic behaviour, temperature influence, recyclability, etc.). However, the achievable goals are numerous: lighter components allow us to improve the energy efficiency
and to reduce the power loss in passive phases of the work cycle; new, highly automated, production cycles can be implemented in the industries; the differences,
in the mechanical behaviour of composites, ceramics and polymeric material could be used to improve, from a fluid point of view, the performance of earth moving
and agricultural machines. An example is the manifold prototype for cartridge valves in Fibre Reinforced Plastic (FRP) which allows substantial weight saving and a
reduction of machining phases without loss of mechanical performance.

Acoustic Design and Noise Control

This is another sector in which IMAMOTER’s objective is to contribute to the development of advanced methods to characterize the complex noise sources; to
plan effective control noise solution; to optimize the acoustic behaviour of machines and their components. An example of the innovative methods used in IMAMOTER- CNR is the active noise control technique (Fig. 10), which is based on sensors and actuator integration, coupled by means of a control system. The
signals acquired by sensors and elaborated by control units are sent, “180° out of phase”, to the actuators to reduce the acoustic and/or vibrational field. But other
methods are currently used to optimize the acoustic field made by a source, not only in terms of noise level reduction but also from a perceptive point of view, the
Sound Quality is an example. By means of binaural record techniques, the use of hearing tests and the use of statistic methods the Sound Quality allows us to study
the noise perception linked to psycho-acoustic and cognitive aspects.

It is therefore possible to evaluate not only the noise, in the strict sense of the word, but also the “quality” sensation that the noise transfers. To measure the acoustic material absorption and to identify and classify the different noise emission area of a complex source, the sound intensity measures could be used. For example, IMAMOTER-CNR has used this technique in the fluid power field to determine the main noise emission areas in a hydraulic pump, finding one of them in thesuction port.

Fig. 10: Example of active noise control performed in earth
moving machines cab

Figure 11 shows a research project regarding the identification of sound emission characteristics of periodic sources (i.e. pump, motor, gear box, etc.) by means of a synchronized sampling at every cycle (GATING method). This analysis allows us to locate many kinds of defects and to characterize the quality of the superficial treatment of rotating parts.

Fig. 11: These graphs are refer to three sets of gears having
different material typology and superficial treatment;
A) low quality gear; B) good quality gear; C)
damaged gear

Fig. 13: ROPS (Roll-over Protective Structure) and FOPS
(Falling-object Protective Structure) certification

Vibro-Acoustic and Ergonomics

The Agricultural and Earth Moving Machines are of primary importance with regard to noise and vibrations reduction. Our experience in this field is a reference point and could be extended to other sectors. For example computational and experimental analysis could be performed at IMAMOTER-CNR to: measure the vibration transferred to the operator’s body and to the hand-arm system according to current standards; to suggest new vibration measurement methodologies to support new standards; to propose optimized solutions in term of operator ergonomics and quality of components; to characterize and optimize closed volumes from a vibro-acoustic and soundquality point of view. IMAMOTER-CNR’s work is based on a strong interaction between vibro-acoustic simulation FEM/BEM, experimental acquisition and numerical optimizationby means of multi-objective genetic algorithms.

Fig. 14: Hand-arm system and seat vibration measurement
equipment

These methods are used to find the best solution when a relationship between dynamic behaviour and machinery vibro-acoustic performance exists. In many cases our studies brought us to implement very effective
passive sound proofing to reduce the noise. In the next figure is shown an example of measurements performed to reduce the vibrations transmitted to the human body; in this analysis we used traditional accelerometer and
untraditional laser vibrometer, a matrix of capacitive sensor applied to the control handgrip and test ring to measure the vibration transmitted in agricultural and earth moving machines.

Fig. 15: Acquisition system to measure vibrations in earth
moving and agricultural machine

The acquired experiences are a reference point and could be extended to other sectors of interest, in this context we are collaborating with many industrial partners and universities.

Educational Activities

The broad sense of the transfer of knowledge is a significant component of the external interface of the Institute. For the purpose of illustration, the educational activities can be divided into two groups, formal and
informal:
    The first one includes all activities performed within or in relationships with Universities, in particular: the University of Ferrara, the University of Modena and Reggio Emilia, and the University of Torino. Two
typical schemes are applied: teaching and tutoring. According to the first, the IMAMOTER personnel are presently involved in many courses, most of which cover specialized fields (e.g. fluid power, noise, microcomputers and micro-controllers). The second scheme is focused on the assistance offered to students during their Thesis or Doctorate research, which in most cases is carried out on the premises of the Institute. The actual number of students involved is variable, ranging between two to five per year.
The second group includes various educational activities which do not have (or at least often do not have)predefined implementation schemes but try to fulfil specific requests coming from external parties. Typical examples are Seminars given to people from a single industry or a group of industries on specific subjects in the expertise of the Institute (e.g. fluid power, noise and vibration, and safety of machines). These events are
sometimes managed by the Institute, sometimes by external centres.
    It is to be remarked that the educational activities are not separate and independent. In fact, they can provide useful suggestions about future investigations, and give the opportunity of producing dedicated materials (e.g. original monographs).

Summary

        The complete definition of the know-how of the Institute - which could be better named it’s competence spectrum - is difficult because it does not exist independently but must be extracted artificially from the
“common practice” of individuals and groups. However, by considering it among the communication channels available to external parties, it could be possible to summarize three main competence areas:
    The expertise in using a number of advanced numerical simulation tools (e.g. codes for structural analysis and both static and vibrational optimization, analysis of flow fields, analysis of sound fields, analysis
and control of dynamic systems), where the term “use” implies the ability of stating the problem at the beginning and evaluating the results at the end;
    The expertise in designing and (possibly) performing tests and experiments by planning the proper layout, procedures, instrumentation and data analysis in special fields (e.g. noise and vibration analysis, structural
analysis, performance of fluid power circuits and components);
    The expertise which comes from the long and deep acquaintance with a number of cultural fields - essentially coincident with those mentioned in points 1 and 2 - and the consequent “broad band” knowledge. An additional case is the field of Standards, here in the sense of their interpretation and application (e.g. the renowned Machine Directive issue by the EU).
The competence spectrum evolution is to be seen, as a general rule, in the medium and long term, but discrete steps may occur. The new material field is an example.

Location	Ferrara, Italy
Contact Person:	Ing. Antonino Bonann, Ing. G.L. Zarotti
Address	IMAMOTER - C.N.R. Institute for Agricultural and Earthmoving Machinery of the Italian National Research Council Via Canal Bianco, 28 44100 Cassana (Ferrara) - Italy
Telephone number	+39-0532-735626 / +39-0532-735616
Fax number	+39-0532-735666
Email	a.bonanno@imamoter.cnr.it, gl.zarotti@imamoter.cnr.it
Internet Site	http://www.imamoter.cnr.it

From Editor

FLUID POWER RESEARCH CENTRES WORLD-WIDE