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Mectron Project

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Subprojects

Control-By-Wire

The Control-by-Wire project regarding to Human Factors aspects, aim at studying innovative Steer-by-Wire systems designed around the needs of safety and driving performances of the drivers.
The project follows two research activities, that are:

• Architectural design of an Ergonomic Steer-by-Wire, that is, a safe and easy-to-use system able to improve the performance of the drivers. Goal: to improve driver’s performances in different driving scenarios.
• Design of a system able to monitor and mitigate the cognitive effort of the driver by measuring the interactions between the driver and the Steer-by-Wire. Goal: to reduce the driver’s cognitive effort in case of high values and improve the driver’s attention to the road.

Activities

• SoA of Human Factors studies on Steer-by-Wire applications and selection of the best reactive torque solutions able to improve the performances of the drivers.
• Design of an Ergonomic reactive torque actuator for a Steer-by-Wire system through a User Centred approach (Ergonomic Steer-by-Wire – ESBW).
• Test and re-design of the ESBW on the driving Simulator: analysis of the reactive torque configurations able to improve the performances of the driver in different driving conditions.
• Analysis of the Steer-by-Wire system as a sensor of the driver cognitive effort (driver Workload).
• Design and validation tests on the driving simulator of Workload indexes based on Steering wheel parameters (i.e. steering torque, steering angle, etc…).
• Design of a Workload mitigation system able to reduce the driver’s cognitive effort in case of high values and avoid risk conditions during driving.

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Fluid Power for Mechatronics

Design, development and electro - hydraulic management of fluid power components and systems characterized by a strong electronic integration, as hydraulic pumps and motors, control valves, proportional valves and electro-piloted hydraulic circuits for industrial and mobile applications.

Activities

• Hydraulic pumps and motors test rig design and installation; hydraulic pumps and motors steady state behaviour measurement and analysis, high pressure ripple measurement, displacement control systems dynamic behaviour improvement.
• Hydraulic control valves test rig design and installation; hydraulic valves steady state and fatigue behaviour measurement and analysis, electro-hydraulic control and proportional valves dynamic behaviour improvement.
• On field supervising of complex systems with electro-hydraulic control and management: data acquisition portable system design and setting.
• Design centre organization to model and simulate fluid power electro – hydraulic controlled components and systems.

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Advanced Materials for Mechatronics

Mechatronic materials: Magnetorheological fluids (MRF), Shape Memory Alloys (SMA), Electroactive Polymers, (MEMS)

Activities

Mechatronic (or smart) materials can quickly and reversibly change some of their physical properties (such as shape, elasticity, viscosity…) when they are subjected to some excitation (electric or magnetic field, temperature change…). That physical input can either come from an external source (in this case the device works as a sensor or a sensor/actuator) or  it can be generated by a controlled source (the material behaves like an actuator). Mechatronic materials are useful to design and build silent, compact, fully controllable, low inertia and high force to weight ratio devices. With MECTRON project a Mechatronic Materials Laboratory (LAMM) has been set up, headed by Professor Eugenio Dragoni and located at DISMI, (Department of Engineering Sciences and Methods) of Modena and Reggio Emilia University. Materials and technologies studied by DISMI are:

• Magnetorheological Fluids
• Shape Memory Alloys
• Electroactive Polymers
• MEMS

MR Fluids are suspensions of micron sized (0.1-10 ?m) ferromagnetic particles in hydrocarbon oils or silicon or water based fluids. Other substances are added to avoid particles wear or to control particles sedimentation. Exposed to a magnetic field, MR fluids change their viscosity very quickly (a few milliseconds). Then fluid behaviour dramatically changes: the liquid turns to a viscoelastic solid with a field dependent yield stress. Possible applications range from controllable dampers and shock absorbers to smart brakes and clutches.
Shape Memory Alloys (SMA) are binary alloys (usually Nickel-Titanium) which change their crystalline structure when heated above a critical temperature. In the transformed state the elastic module changes as well as the shape, which reverts to a previously memorized one. Moreover SMA have superelastic properties: they can withstand up to 10% elastic deformation.
Electroactive polymers are elastic materials (acrylic or silicone polymers) showing large deformations if exposed to an sufficiently intense electric field which is then altered by the deformation of the polymer itself. Materials with electroactive properties are dielectric, incompressible and isotropic elastic solids. They behave like capacitors whose capacity is function of the mechanical stress or electric field they are exposed to. These polymers are normally employed in the form of thin films, and the electric field is applied  perpendicular to the film plane.
MEMS (Micro Electro-Mechanical Systems) are the integration of mechanical elements, sensors, actuators, and electronics on a common silicon substrate through microfabrication technology. While the electronics are fabricated using integrated circuit process sequences, the micromechanical components are fabricated using compatible "micromachining" processes that selectively etch away parts of the silicon wafer or add new structural layers to form the mechanical and electromechanical devices. Microelectronic integrated circuits can be thought of as the "brains" of a system and MEMS augments this decision-making capability with "eyes" and "arms", to allow microsystems to sense and control the environment. Because MEMS devices are manufactured using batch fabrication techniques similar to those used for integrated circuits, unprecedented levels of functionality, reliability, and sophistication can be placed on a small silicon chip at a relatively low cost.
Through LAMM, MECTRON proposes a centre of expertise for research on smart materials and development of smart materials devices. Some demonstrators of those technologies are currently under development:

• MR Fluid dampers for high and low frequencies;
• High torque to weight ratio SMA  actuators;
• Electroactive polymers based actuators for robots.

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Instruments

CONTROL BY-WIRE

Oktal Driving Simulator (www.oktal.fr)

• Car cabin equipped with a TRW ASWS steering wheel, pedals (brake, clutch, accelerator) and a dashboard which simulate the vehicle’s instruments panel (i.e. tachymeter, RPM, lamps, etc…);
• Projector device and projector screen for the display of the driving scenario;
• Scaner2 (www.scaner2.com), Simulation Software which manages the vehicle model controlled by the driver, the traffic conditions, weather, scenario projection,  data recording of the scenario environment.

Software and Hardware devices for the analysis of the driver’s mental load

• PDT: Workload monitoring system for the assessment of driver mental load through the Peripheral Detection Task approach;
• LCD glasses: system for the driver’s visual load monitoring through the visual occlusion task.

FLUID POWER FOR MECHATRONICS

• Design centre: twelve pc and a server machine provided with commercial lumped parameters software (AMESIM©), CFD software (SWIFT©), data acquisition and management (LABVIEW©).
• Hydraulic pumps and motors test rig (group 1 and 2)

Hydraulic proportional valves test rig
Technical data:
                               Max. Power: 40 kW
                               Max. Pressure: 350 bar
                               Max. Flow Rate: 150 l/min
                               Tank Capacity: 400 l

• Sensors and Transducers:

5 Pressure transducers: 1 Absolute Pressure Transducers (0.25 %  Accuracy, 10 bar Range, 4-20 mA output); 4 Gage Pressure Transducers (0.5 % Accuracy, 345 bar, 4-20 mA output).
3 Gear type flow meter: (0.4 – 80 l/min Range, max pressure 400 bar, 2 measurement channels, 2 square waves output, supply voltage DC 24 V ?20% ).
1 Torque sensor: (100 Nm Range, max speed 9000 rpm, 2x360 pulses 90° displaced TTL, 0?5 V DC voltage output, 0.2 Accuracy class, Linearity < ?0.2% of full scale).
1 Encoder: (Output circuit: line driver, Output current 40 mA, Output Frequency 100 kHz Power supply 5V?5%, bidirectional with index pulse, STD pulse rate 1024, Operating temperature -40°C/+100°C).

• Data Acquisition System (National Instruments):

PXI 1036DC (chassis for the pc hardware and data acquisition cards)
NI PXI 6251 Analog signal acquisition card
NI PXI 6624 Digital signal Counter Timer acquisition card
NI Cardbus 8310 (data acquisition system - laptop interface)

• Additional components (data acquisition modules and signals conditioning).

ADVANCED MATERIALS FOR MECHATRONICS

Main instrumentation:

• Uniaxial electromechanic 5kN testing machine.
• Gaussmeter to measure static and variable magnetic flields.
• Hydraulic biaxial  25 kN (force) and 200 Nm (torque) testing machine with a maximum working frequency of 20Hz.
• Electrodynamic shaker (maximum frequency 2000 Hz, payload 160 kg).
• Accelerometers and signal acquisition system to measure vibrations.
• Labview data acquisition and processing software.
• FEM analysis software: ABAQUS, ANSYS, COMSOL Multiphysics.