What is a Cylindrical Robot? | 10+ Important Applications | Advantages and Disadvantages

Cylindrical Robot

Image Credit: Wikipedia commons

The subject of discussion: Cylindrical Robot and its features

Cylindrical Robot

Cylindrical Robot Definition

The cylindrical robot has a rotary joint for rotation and a prismatic joint for angular motion around the joint axis. The rotary joint moves in a rotational movement around the common axis. In contrast, the prismatic joint will move in a linear motion.

Cylindrical Robot
Cylindrical Robot

The main arm of cylindrical robots goes up and down. A cylinder built into the robotic arm produces this motion by stretching and retracting itself. Gears and a motor drive the movement of many of these cylindrical robotic versions, while a pneumatic cylinder drives the vertical motion. Assembly processes, management of machine tools and die-cast equipment, and spot welding are all done with cylindrical robots.

Cylindrical Coordinate Robot | Cylindrical Polar Coordinate

Cylindrical robots use a 3-D coordinate system with a preferred reference axis and relative distance from it to determine point position. The distance to a selected reference positioning and the relative axes direction, and the distance to the axis vertical from a designated reference plane are often used to specify the point location.

The system’s origin is the point at which all three coordinates can be written as ‘0’ and this is the point where the reference plane and the axes meet. To distinguish it from the polar axis, which is the ray that lies in the reference plane, initiating at the origin and points to the reference direction, the axis is referred to as the cylindrical or longitudinal axis.

The radial distance is the distance from the axis. Simultaneously, the angular coordinate is frequently mentioned as the azimuth. This belongs to a 2D polar coordinate structure in the plane around the point, parallel to the reference plane; the radius and azimuth are sometimes stated as polar coordinates. The height or altitude, longitudinal angle, or axial position are both labels for the 3rd coordinate.

This is also known as “polar cylindrical coordinate” and “cylindrical polar coordinate,” It’s used to describe the position of stars in galaxies.

These robots are convenient for artefacts that need rotational symmetry along their longitudinal axes.

Cylindrical Robot Design | Cylindrical Configuration Robot

Cylindrical Robot Working

The motion of this robot is fundamentally up and down at the main part of the body and circular at the base and the name ‘cylindrical robot’ originate from it’s the physical shape of the cylindrical work-envelope. In this up-and-down motion is generated by a pneumatic cylinder, and the rotation is normally generated by a motor and gears assembly. The robotic arm will go up and down over a vertical member, thanks to the design of this sort of body. The arm will stretch and contract as well as rotate along the vertical axis. The manipulator will now function in a cylindrical space thanks to this design.

The limb’s length determines the radius of the cylindrical space, and the displacement along the vertical member determines the height. A revolute joint at the fixed frame, a cylindrical type joint about the axis of rotation, and a prismatic type joint in the manipulator’s arm creates the cylindrical manipulator base body and the direction of the end-effector is determined by the arm’s extension, height, and revolution around the main body-axis and these are the essential 3-variables that must be managed in order to location a cylindrical robot’s end-effectors. To put it another way, this arrangement style creates a cylindrical co-ordinate system that can be regulated in the same way.

Joining a wrist to the end of the arm cylinder permits further mobility. And this wrist is complex enough to agree on additional degrees of freedom, and the Pitch (which is measured by up-and-down motion at the wrist), roll (which is computed by the rotating motion at the wrist), and yaw are the three styles. The side-to-side motion usually measures the yaw at the wrist. These categories of Wrist with 1 or 2 or 3 of these movements are existing and accessible in the markets, depending on the cost and applicability.

Cylindrical Robot Specifications and Characteristics

ParameterCharacteristics
RangeWide range available
Repeatability0.1-0.5mm (Vary as per design )
PayloadVary in between 5 to 250kg
Number of AxesMinimum Three (two linear)
Working EnvelopeTypically Large (Vertical strokes as long as radial strokes)
SpeedAverage,  1000 mm/s
CostComparatively in expensive as per their size and payload.
Courtesy : Presentation of Y M Hamad

Control of Cylindrical Robot

Under the constraints imposed by the mechanical structure’s architecture, an industrial robot’s control systems decide its flexibility and performance. The control scheme provides the robot with a sequential order to execute. The machine calculates the potential position values for each step and monitors the movement’s absolute position.

The control system measures the theoretical/actual discrepancy and other calculated values and stored data (e.g., theoretical speeds) when the robot is in operation and generates actuating variables to move the robot. In today’s industrial markets, robot manipulators play a critical role. Robots perform tasks that need high precision and repeatability, such as wrapping, labelling, and package assembly.

In recent years, industrial robots have been in high demand for activities that are repetitive (such as picking and placing objects), messy (such as cleaning drainage pipes), dangerous (such as welding and spray painting), and difficult (such as assembly or replacement of electronic parts). The robot manipulators can execute a task with high precision, autonomy, durability, independence, and responsibility.

Furthermore, if the workspace includes both fixed and moving obstacles, motion control becomes more difficult because each of the robot’s bodies must clear an obstacle. The kinematics model of manipulator was developed using various methods by researchers. Due to mechanism and workspace constraints, non-reachability of end-effectors, and associated mechanical singularities, autonomous motion control of the manipulator’s arms is not a simple job.

Modelling the motion of a pair of cylindrical manipulators operating in a confined workspace as a method of first-order nonlinear differential equations is one way to schedule and regulate their movement while obeying system limits and singularities, removing fixed and moving obstacles.

The Lyapunov-based Control Scheme can then be used to derive a series of nonlinear, time-invariant, continuous control laws for generating collision-free cylindrical manipulator motions. This scheme’s versatility and sophistication are the key reasons for its use. Furthermore, the analytic representation of machine singularities and limits is simple, as is the extraction of control rules.

Image Source: ResearchGate

Cylindrical Robot Workspace | Work Envelope of Cylindrical Robot | 3 link cylindrical robot

The Cylindrical Robot’s end reach is a cylinder whose dimension has been measured by the robot’s various components’ motion limit. However, any joint’s maximal and minimum motion limit occurred on both sides.

As a result, the workspace, which is made up of the points where the robotic arm’s endpoint can be placed, is not a complete cylinder, but rather an intersection of two concentric cylinders and inner cylinder’s dimensions are determined by the robot parts’ minimal motion limits.

The joints travel around their axes within a cylindrical work envelope’s confines. The cylindrical-shaped work envelope can be seen visualized in the figure below:

Cylindrical Robot Example | Cylindrical Industrial Robot

Cylindrical Robot Arm

What are Cylindrical Robots used for? | Cylindrical Robot Applications

Cylindrical robots are commonly used in small spaces, and they are ideal for objects that require circular symmetry (e.g. wires, pipes). They’re also well-suited to standard pick-and-place work in manufacturing settings.

Cylindrical robots can be used for other varied tasks, including:

  1. Spot Welding
  2. Handling of die-casting machines
  3. Machine handling equipment in general
  4. Procedures for grinding
  5. Assembly operations
  6. Palletizing
  7. Loading and unloading of machines
  8. Investment casting
  9. Applications in the foundry and welding
  10. Manipulation and storage of unique payloads
  11. Packing meat
  12. Applications for coatings
  13. Injection moulding
  14. Assembling of packages and products in the manufacturing and packaging industry

They’re frequently used in electronics products, specifically for clean room applications and all the other applications listed above.

Can a Cylindrical Robot replace a Cartesian Robot?

Since both the Cartesian and Cylindrical base robots can meet points in three dimensions, they can be interchanged while maintaining a standard minimum workspace. Each robot base has its own set of appropriate applications. Cartesian robots may be better for some uses, whereas cylindrical base robots may be better for others. Even so, the two forms can be swapped for certain benefits and drawbacks.

What are the advantages and disadvantages of Cylindrical robots?

Cylindrical Robot Advantages

Cylindrical Base Robots can travel between required points faster than Cartesian Robots, which is an advantage, mainly when these two points are in identical radius. In that case, two of the three movements are in parallel to each other.

Cylindrical Robot Disadvantages

There are several drawbacks of cylindrical robots few of them are listed below:

  • Since robots with a rotary axis must counteract the object’s inertia while spinning, their total mechanical rigidity is decreased. Their repeatability and precision are both limited in the direction of the rotary action. A more sophisticated control scheme is needed for cylindrical configurations than for cartesian configurations.
  • The overall mechanical rigidity is lesser because this robot’s rotatory axis must overcome the object’s inertia during its rotation.
  • The repeatability and accuracy are also less in the direction of rotation.
  • Another major drawback of this system is that changing directions from the Cartesian coordinate system to the cylindrical coordinate system usually required a significant amount of time and a more sophisticated control system.

About Esha Chakraborty

I have a background in Aerospace Engineering, currently working towards the application of Robotics in the Defense and the Space Science Industry. I am a continuous learner and my passion for creative arts keeps me inclined towards designing novel engineering concepts.
With robots substituting almost all human actions in the future, I like to bring to my readers the foundational aspects of the subject in an easy yet informative manner. I also like to keep updated with the advancements in the aerospace industry simultaneously.

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