CRE CRE Robot Kinematics & Mechanics

Question 1

What does forward kinematics calculate in a robot arm?

Accepted Answer

End-effector position and orientation from joint angles

Answer

Forward kinematics computes the end-effector position and orientation given the joint angles of the robot.

Question 2

How many parameters does the Denavit-Hartenberg (DH) convention use to describe each joint?

Accepted Answer

4

Answer

The DH convention uses four parameters (a, d, alpha, theta) to describe the geometric relationship between consecutive joint frames.

Question 3

Which joint type allows only rotational motion about a single axis?

Accepted Answer

Revolute

Answer

A revolute joint permits rotation about a single fixed axis and contributes one rotational degree of freedom.

Question 4

In robotics, the Jacobian matrix relates:

Accepted Answer

Joint velocities to end-effector linear and angular velocities

Answer

The Jacobian maps the joint velocity vector to the resulting end-effector linear and angular velocity vector.

Question 5

The workspace of a robot arm is defined as:

Accepted Answer

The set of all positions and orientations reachable by the end-effector

Answer

The workspace is the collection of all end-effector positions and orientations achievable given the robot's joint limits and geometry.

CRE - Certified Robotics Engineer Practice Test