# NPTEL Robotics Week 3 Assignment Answers

NPTEL Robotics Week 3 Assignment Answers:- In this post, we have provided the answers to the NPTEL Robotics Week 3. All the answers are provided here on the basis of data available on the internet.

## NPTEL Robotics Week 3 Assignment Answers 2022

Q1. Rot (Y, B), that is, rotation about Y axis by an angle ß is represented by a 3 x 3 matrix, and Rot (Z, y), that is, rotation about 2 axis by an angle y is represented by a 3 x 3 matrix, then Rot(?, 60°) x Rot (2,30) is given by

`Answer:- d`

Q2. Which one of the following combinations of the statements given below is Correct with respect to a rotation matrix?

Statement 1: Each row/column of a rotation matrix is a unit vector.
Statement 2: The inner (dot) product of each row of a rotation matrix with each other row becomes equal to 0. Statement 3: Inverse of a rotation matrix is nothing but its transpose.
Statement 4: Rotation matrices are commutative in nature.

• a. Statements 1 and 2 are correct
• b. Statements 1, 2 and 3 are correct
• C. Statements 1 and 4 are correct
• d. All the statements 1, 2, 3 and 4 are correct
`Answer:- b`

Q3. If a Cartesian coordinate frame is rotated by a angle about Z axis, followed by a rotation of B angle about P axis, followed by rotation ofy angle about & axis, then in order to represent the final frame with respect to reference frame, the composite rotation matrix can be represented by

• a. ROTcomposite = ROT(2,a) ROT(?.P) ROT(&.v)
• b. ROTcompoite = ROT(R,y) ROT(?.P) ROr(2, «)
• C.ROTcomposite = ROT(?.p) ROT(8.y) ROT(2,a)
• d. ROTcomposite = ROT(2, «) ROT(R,y) ROT(?.B)
`Answer:- b`

Q4. Which one of the following statements is TRUE?
The concept of Roll, Pitch and Yaw angles can be used to

• a. represent the position of end-effector of a manipulator with respect to its base co- ordinate system.
• b. represent the orientation of end-effector of a manipulator with respect to its base co- ordinate system.
• c. represent both the position and orientation of end-effector of a manipulator with respect to its base coordinate system.
• d. represent neither the position nor orientation of end-effector of a manipulator with respect to its base coordinate system
`Answer:- b`

Q5. A frame {B} is rotated about Xy axis of the Universal coordinate system by 60 degrees and translated along Xy. Yu and 2y by 1,2 and 1 unit(s), respectively. Let the position of a point Q in {B} is given by 1 2 31. UQ is found to be equal to

• a. [2.51 6.15 3.61]”
• b. [3.52 4.65 3.72]
• C. (2.000 0.402 4.232]
• d. 3.54 3.96 6.42]
`Answer:- c`

Q6. According to Denavit-Hartenberg notations, link and joint parameters represent

• a. the structure of a link only.
• b. the relative positions of neighboring links only.
• c. the relative positions of neighboring links and structure of a link, respectively.
• d. the structure of a link and relative positions of neighboring links, respectively.
`Answer:- d`

Q7. According to Denavit-Hartenberg notations, the length of i-th robotic link can have

• a. positive value only.
• b. negative value only.
• C. zero value only.
• d. either positive or zero value.
`Answer:- d`

Q8. According to Denavit-Hartenberg notations, the angle of twist of i-th robotic link can have

• a. positive value only.
• b. negative value only.
• c. zero value only.
• d. either positive or negative or zero value.
`Answer:- d`

Q9. For a Revolute Joint,

• a. joint angle is variable but angle of twist, length of link and offset of link are kept fixed.
• b. angle of twist is variable but joint angle, length of link and offset of link are kept fixed.
• C. length of link is variable but joint angle, angle of twist and offset of link are kept fixed.
• d. offset of link is variable but length of link, angle of twist and joint angle are kept fixed.
`Answer:- a`