What Are the Main Parts of a Collaborative Robot?

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Updated October 29, 2026

A collaborative robot is a robot that interacts directly with people. A collaborative robot arm can have joints, sensors, a controller that commands motion, and an end tool at its tip.

Contents

A collaborative robot and a person work in the same space.

A person
A collaborative robot
A shared space

What you will learn

Name the main parts of a collaborative robot.
Explain what joints and sensors do in the arm.
Tell what the controller and the end tool are for.

Before you start

Knowing what a robot is, from the first article of this topic, is enough.

What do the arm and its joints do?

The arm is built around joints. Many collaborative robot arm designs use flexible joints to absorb external impact forces. These are design components; flexible joints and force sensors alone do not guarantee that every interaction with a person is safe.

The same design often adds other safety parts. A study in the journal Sensors says the design of collaborative robot arms often incorporates flexible mechanisms and force sensors to detect and absorb external impact forces.

Think of your own arm. The shoulder, elbow and wrist are joints, and they let the arm bend and reach.

The arm is a chain of segments joined at joints.

Base
Arm segments
Joint

Each joint turns a little, and together the joints let the arm bend and reach.

NIST’s project aims to develop test methods and metrics for robot workcells consisting of robotic arms, hands and mobile platforms. A workcell is a work area arranged around a robot and its associated components. The arm is one of several kinds of robot parts that appear there.

Which sensors does a collaborative robot use?

Depending on the design, it may use cameras, touch sensors and force sensors. A review in Frontiers in Neurorobotics names RGB-D cameras, tactile skins and force/moment transducers. A tactile skin is a surface that feels touch.

The same review focuses on four senses: vision, touch, audition and distance. Audition means hearing.

Some sensors sit inside the arm. A robot can use torque sensors embedded in its joints to estimate force. A torque sensor measures how hard a joint is being twisted.

Sensors let a robot see, touch and measure force at a joint.

A vision sensor
A touch sensor
A torque sensor in a joint

What do the controller and the end tool do?

The controller is the part that commands the arm's motion. In one study of a specific force-control system, when cumulative joint-position error exceeded a preset threshold, the controller triggered an alarm, stopped motion control and switched off output torque while retaining gravity compensation. This describes the tested design, not a general guarantee for every robot arm.

At the tip of the arm sits the end tool, called an end-effector. A force or torque sensor is usually installed on an end-effector to measure the contact force on end-of-arm tooling. End-of-arm tooling is the tool at the end of the arm.

The controller is linked to the arm, and the end tool sits at the arm's tip.

Controller
Arm
End tool (end-effector)

Real-world example

Compare the robot with a person pushing a shopping trolley. The brain is the controller, the eyes and skin are sensors, the shoulder and elbow are joints, and the hand is the end tool. This analogy helps recall parts that a robot arm can have.

Common misunderstandings

A collaborative robot is only an arm. An arm is one part. A system can also include sensors, a controller and an end tool.

Force sensors sit in only one place. They can be embedded in the joints, and they can also be installed on the end-effector.

A robot senses only by seeing. The review lists vision, touch, audition and distance.

Frequently asked questions

Is a collaborative robot the same as an industrial robot?

Not necessarily. NIOSH distinguishes collaborative robots that interact directly with people from traditional industrial robots that work in cells or cages away from workers; the source does not say collaborative robots are outside the industrial-robot category.

A collaborative robot interacts directly with people; some arm designs use flexible joints. These features alone do not guarantee safety.
Depending on the design, it may use cameras, tactile skins or force sensors; torque sensors can be embedded in joints.
The controller commands the arm; one studied system stopped motion control after a preset cumulative joint-error threshold was exceeded while retaining gravity compensation, and the end tool sits at the arm's tip.

Terms in this article

English and Vietnamese terms, with the meanings used here. Hover, tap or Tab to a term with a dotted underline for an explanation as you read.

Collaborative robotRobot cộng tác: A robot that interacts directly with people.
JointKhớp: A connection allowing parts of a robotic arm to move relative to each other.
SensorCảm biến: A component gathering information such as images, contact or applied force.
Torque sensorCảm biến mô-men xoắn: A sensor measuring a twisting effect, for example at a robot joint.
ControllerBộ điều khiển: The component that commands a robotic arm’s movement.
End-effectorĐầu công tác: The part at the end of a robotic arm that interacts or works with an object.
End-of-arm toolingDụng cụ cuối cánh tay: Tooling attached at the end of a robotic arm to carry out a task.
WorkcellÔ làm việc robot: A work area arranged around a robot and its associated components.

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