Pune University Question Papers BE Mechanical Engineering Elective-II Sem-II)

Pune University Exam Paper

ROBOTICS B.E. (Mechanical Engg.)

(Elective – II) (Sem – II)(Theory)

Time: 3 Hours]                                                                                           [Max. Marks :100

Instructions to the candidates:

1)                    Answer three questions from section I and three questions from section II.

2)                    Figures to the right indicate full marks.

3)                    Draw suitable sketches wherever necessary.

4)                    Assume suitable data, if necessary.

5)                    Answers to the two sections should be written   in separate answer books.

6)                    Use of electronic pocket calculator is allowed.

SECTION – I

QI) a) Explain why homogeneous coordinates are required in modeling of robotics manipulators.  [8]

b) Frame{2} is rotated with respect to frame {I} about the x axis by an angle of 70°. The position of the origin frame {2} as seen from frame {I} is !D2 = [7.0 5.0 7.0]T. Obtain the transformation matrix 1Tp, which describes frame {2} relative to frame { I }. Also, find the description of point P in the frame {I} if 2p = [2.0 4.0 6.0]T. Draw frames.                                                            [10]

OR

Q2) a) Explain D-H Parameters.                                                                                            [8]

b) A frame {U V W} is located at a point P @15, 20, 12) with respect to {X Y Z } having axis U opposite to Z axis, axis X parallel to V axis Both frames are right handed. Determine location of point Q which is XYZQ = @5, 15, 25).                                                                             [10]

Q3) a) Explain the factors on which the number of solutions to given inverse kinematics model depends.                                                                                                                [8]

b)                Explain Lagrange-Euler formulation for n-DOF manipulator.                         [8]

P.T.O.

OR

Q4) a) Explain Inverse Kinematics of PUMA manipulator.                              [8]

b)                 Sketch the approximate reachable workspace of the tip of a two link planar arm with revolute joints. For this arm the first link is thrice as long as the second link and the joint limits are 30° < Gj < 180° and -100°

< e2< 160°.                                                                                                            [8]

Q5) a) The second joint of a SCARA manipulator is required to move from Gp = 30° to 150° in 5 sec. Find the cubic polynomial to generate smooth trajectory for the joint. What is the maximum velocity and acceleration for this trajectory?                                                                    [8]

b)                 Explain Industrial robot control systems.                                                           [8]

OR

Q6) a) What are the major differences between the open-loop and close-loop servo systems?          [8]

@b) Describe the architecture of hybrid position/Force control.                              [8]

SECTION – II

Q7) a) Explain hydraulic grippers, with reference to the principle, use and

applications.                                                                                                          [6]

b)                 Discuss various considerations for selection of a gripper.                                  [6]

c)                  Explain need for sensors and vision system in the working and control

of a robot.                                                                                                             [6]

OR

Q8) a)                               Write short note on, Characteristics of sensing devices.      [6]

b)                 What is compliance? Explain active and passive compliance in brief. [6]

c)                  A vacuum gripper is used to lift flat steel plate of dimensions 10 mm

x 500 mm x 700 mm. The gripper uses to suction cups, 120 mm in diameter each, and they are located 400 mm apart for stability. Assume a factor of safety of 1.7 to allow for acceleration of the plate. Determine the negative pressure required to lift the plates if the density of steel is 8054.3 x 10 9 kg/mm3.                                                                                                                [6]

Q9) a) Explain use of strain gauges for force sensing.                                                          [6]

b)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Write a note on redundant Robot.                                                                                                          [4]

c)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 Explain use of robot in are welding.                                                                                                              [6]

OR

QI0) a) Explain different types of speed reduction 8 transmission systems used in robots.    [6]

b)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Explain use of robot in the assembling.                                                                                                         [4]

c)                   Write various technical features required of robot for spot welding and spray coating applications.                                                                                                                              [6]

QII) a) Explain various performance characteristics of induction motors. [6]

b)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                Write note on stepper motor.                                                                                                                           [6]

c)                   Compare hydraulic 8 electrical actuator based on weight, resolution, operating pressure and cost.  [4]

OR

Q12) a) Explain various methods used to enter the programming command into the controller memory.                                                                                                                [6]

b)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               Explain generations of robot programming languages.                                                                               [4]

c)                  Explain WAIT, DELAY, SIGNAL command with suitable examples. [6]

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