Motion Control & Kinematics Flashcards

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

Answer: Joint velocities to end-effector velocities

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

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

Answer: S-curve (7-segment) profile

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

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

Answer: End-effector pose in Cartesian space

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

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

Answer: Motor phase current (and thus torque)

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

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

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

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

In Denavit-Hartenberg (DH) notation, how many parameters describe each joint-link pair?

Answer: 4

DH notation uses four parameters per joint: link length (a), link twist (α), joint offset (d), and joint angle (θ).

Which control topology is used when both position and velocity feedback loops are active simultaneously in a servo system?

Answer: Cascaded (nested) control

Cascaded control nests an inner velocity loop inside an outer position loop, providing tighter dynamic response.