AWS DevOps Motion Control & Kinematics 3

Question 1

In a robotic arm with 6 degrees of freedom, what does the Jacobian matrix relate?

Accepted Answer

Joint velocities to end-effector velocities

Answer

The Jacobian matrix maps joint-space velocities to Cartesian end-effector velocities at a given configuration.

Question 2

Which motion profile minimizes jerk while still limiting velocity and acceleration?

Accepted Answer

S-curve (7-segment) profile

Answer

The S-curve (7-segment) profile adds jerk-limited ramp phases to a trapezoidal profile, reducing mechanical shock.

Question 3

In forward kinematics, what is the primary output given a set of joint parameters?

Accepted Answer

End-effector pose in Cartesian space

Answer

Forward kinematics computes the end-effector's position and orientation from known joint angles or displacements.

Question 4

A servo drive operating in torque control mode primarily regulates which quantity?

Accepted Answer

Motor phase current (and thus torque)

Answer

In torque mode, the drive closes a current loop whose output current is proportional to the commanded torque.

Question 5

What phenomenon occurs when a robot's Jacobian becomes singular?

Accepted Answer

The robot loses one or more degrees of freedom in Cartesian space

Answer

At a singularity the Jacobian loses full rank, meaning certain Cartesian directions cannot be achieved regardless of joint velocity.

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