software based modelling of 3-axis robot.pptx

7/28/2019 Software Based Modelling of 3-axis robot.pptx

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(MATLAB, Simulink and associated software)


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Mechatronics is the integration of mechanical and electroniccomponents into a functional system.

Robots can be called mechatronic devices: but Mechatronicdevices are NOT robots.

A robotic device is additionally defined by programmability

and the ability to move or carry a load. Thus it differs from amechatronic device.


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Robots are workers. Once programmed to perform a task,they will do it repeatedly, reliably and accurately without needfor human intervention.

Can work in hazardous environments.

Can perform tasks humans cannot do: e.g. space exploration,

narrow pipeline motion, moving small/big objects

Can perform industrial work: assembly line work, componentmounting, ship cleaning, etc.

Can entertain: Robotic toys for children


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Mobile Robots: Ability of ground motion by wheeling,walking, hopping, etc.

Size varies a lot

E.g. University of Florida Center for Intelligent Machines AndRobots (CIMAR) autonomous vehicle


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Small scale robots: Inspired by small animals, small size andused for innocuous tasks or for fun.

E.g. Stiquito robot, hexapod robot that moves like a sixlegged animal (see below):


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Nano-robots: also called molecular robots. These are molecular scale robots relying on piezoelectric

motors and biological sensors.

It is a cutting edge research area at this time.


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Anthropomorphic Robots: Humanoid Robots These are the ultimate goals of research in robotics.

Although robot arms, legs, hands, heads have beensuccessfully built, a fully intelligent robot is still far fromreality.

Example: ASIMO Robot (Advanced Step In Innovative Mobility)


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Sensors: Measurement Devices. In the case of robots, tomeasure displacement, light level, speed, distance,acceleration, orientation, temperature, pressure, light level,sound level, proximity, etc.

Actuators: Motors that allow the robots to move. They may be

electric, hydraulic, pneumatic, piezoelectric, or evenbiological.

Controllers, Electronics and Mechanics (i.e. motors, gears,shafts, belts, links, etc.)

Software: data stored in memory that defines the robots

behaviour and response to the working of mechanical andelectrical components.


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Type of anthropomorphic robot resemblinghuman arm .

Software controllable that uses sensors toguide end effector through programmedmotion in workspace in order to manipulatephysical objects.


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Hydraulic drive

Electric Drive

Pneumatic Drive


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Robot manipulators are consisted of a sequence of linksattached at joints.

Each link can move with respect to the preceding link eitherthrough a sliding or a rotational joint.

Objects in 3D space are said to have six degrees of freedom.

3 for position and 3 for orientation. Position can be definedby x and y axes while for orientation we use different anglesalpha, beta and gamma.


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Cartesian Cylindrical

Spherical

SCARA Articulated


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Method used to control End effector or Tool

a) Point to Point: Spot Welding ,pick & placeetc.

b) Continuous Path: Spray Painting, Gluing etc.


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Number of axes Load Carrying Capacity: kg

Maximum speed: mm/sec

Reach : mm Tool orientation: deg

Repeatability: mm

Precision & accuracy: mm

Operating Environment


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In our project we use MATLAB and Simulink along with certainother tools* to create a fully functional simulation of a 3-jointrobot.

The important components used here are any or all of thefollows: MATLAB (to generate the m-files necessary to

provide inputs to the system), Simulink with SimScape,SimMechanics and SimHydraulics (to formulate the kinematicanimation parameters)


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For testing purposes and to check thecalculated parameters the following programsmay be used: RModelo, DHSim, other toolssuch as ROBOTran, etc.

Parameters: Predominantly DH parameters


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SimMechanics is a MATLAB module designed for the designand simulation of multibody rigid systems, which areparticularly suited for robotics.

With SimMechanics software, you can model and simulatemechanical systems with a suite of tools to specify bodies

and their mass properties, their possible motions, kinematicconstraints, and coordinate systems, and to initiate andmeasure body motions. You represent a mechanical systemby a connected block diagram, like other Simulink models.You can also incorporate hierarchical subsystems.

Software like ROBOTrans add additional functions toSimMechanics, thus making it more flexible for robotmodelling.


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MATLAB is used to generate the requisite M-files that containthe parameters necessary for the modelling of the robot (andkinematics).

This M-file is to be used as an input in SimMechanics tomodel a mechanical system.

The Mechanical System is then coupled with anelectrical/electronic system in SimScape to produce the finalmodel of the robot.

The M-File input then drives the system. A VR Sink (VirtualReality Modelling Language) is used to convert the outputsinto the ISO standard VRML format and provide a full 3D

model of the robot. Auxiliary software (ROBOTrans/Rmodelo/DHSim) are used for

testing and convenience as they add to the MATLABfunctions.


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Example of robotic system designed underSimScape and SimMechanics:


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SimMechanics design with per-block parameters and specificdimensions to sub-blocks (note that each link has an M-filefor describing its motion, and that each link is composed ofseveral sub-blocks with different physical dimensions):


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MATLAB allows to design robots in several ways. You candevelop a robot model using SolidWorks (or any othermodelling software), import it into SimScape and then providean input using an M-file.

Or you can directly model the robot in SimMechanics and

obtain the output. Choice in modelling: MATLAB can treat the robot motion as a

multibody mechanical system (classical mechanics) or arobotic system (canonical transformations).

software based modelling of 3-axis robot.pptx

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