This robot design features rotary joints and can range from simple two joint structures to 10 or more joints. The arm is connected to the base with a twisting joint. The links in the arm are connected by rotary joints. Each joint is called an axis and provides an additional degree of freedom, or range of motion. Industrial robots commonly have four or six axes.

CARTESIAN ROBOT DESIGN (These are also called rectilinear or gantry robots)

Cartesian robots have three linear joints that use the Cartesian coordinate system (X, Y, and Z). They also may have an attached wrist to allow for rotational movement. The three prismatic joints deliver a linear motion along the axis.


The robot has at least one rotary joint at the base and at least one prismatic joint to connect the links. The rotary joint uses a rotational motion along the joint axis, while the prismatic joint moves in a linear motion. Cylindrical robots operate within a cylindrical-shaped work envelope.


In this configuration the arm is connected to the base with a twisting joint and a combination of two rotary joints and one linear joint. The axes form a polar coordinate system and create a spherical-shaped work envelope.


Commonly used in assembly applications, this selectively compliant arm for robotic assembly is primarily cylindrical in design. It features two parallel joints that provide compliance in one selected plane.


These spider-like robots are built from jointed parallelograms connected to a common base. Designed by Reymond Clavel in the mid ’80s. The parallelograms move a single EOAT in a dome-shaped work area. Heavily used in the food, pharmaceutical, and electronic industries, this robot configuration is capable of extremely fast, delicate, and precise movement.




A new kind of robot has made its way into industrial settings, challenging our preconceived notions of robotics. These robots’ main feature is the ability to work safely alongside humans, and now it seems human-robot collaboration is the most sought-after characteristic for robots. There’s a lot of talk about them on the web, but what are they really? Until now, robots have always been big, strong, robust devices that work on specific tasks that were designed for them. They’ve been kept in cages and surrounded by guards designed for safety purposes. Their bright color was used to warn surrounding workers about the danger they represented. And it took a lot of programming skills just to set up these robots.

COBOTS (Collaborative robots), on the other hand, are designed to safely work with humans or inside human environments. They’re built with safety features such as integrated sensors, passive compliance, or overcurrent detection. The integrated sensors will feel external forces and, if this force is too high, lead the robot to stop its movement. Passive compliance is produced by mechanical components. If an external force acts on a joint, this joint will submit itself to this force. So, in the case of a collision, the joint will move in the opposite direction or stop completely to avoid causing injury.

Most collaborative robots can be easily taught by demonstration, rather than requiring a deep knowledge of programming. Thanks to their ease of implementation and the fact that no additional safety features are required (no fences, switches, etc.), they can be brought on-line much more quickly. The majority of collaborative robots can also be moved around the factory floor in order to perform a different task at another station. Being more dexterous and flexible, they can perform more tasks and even do whatever a human can do. In short, collaborative robots are the ideal new co-worker.



Before we get into the details about collaborative robots, let’s get up to speed on the different terminology used in the robotics world. It can get confusing (even for us) because people sometimes use certain terms interchangeably, such as “force limited robots,” “collaborative robots,” and “cobots.” They may have the same general purpose, but they can be interpreted very differently. In fact, all these terms mean the same thing: a robotic device that is made to work in collaboration with humans. Or, more specifically, a robot that will help a human worker execute tasks that are too hard on his or her body, such as lifting heavy weights or doing repetitive movements. The number of applications that can be done by robotic co-workers is virtually unlimited.


The term “collaborative robot” is often a misnomer. In fact, although a collaborative robot is designed to work alongside humans, the device itself is not necessarily force limited. This means that the robotic cell is monitored, is safe for human co-workers, and relies on at least one of the 4 collaborative modes. The term “collaborative robot” is unique in that it describes the fact that humans and robots work with each other, not whether the robots are force limited.


A force limited robot uses one of the 4 types of collaboration that can be accomplished with robots. In fact, a force limited robot is a robot that’s specially designed to work alongside humans. They have built-in force-torque sensors that detect impact and abnormal forces. The sensors stop the robot when overloaded. This means that if the robot’s arm hits something (…like a worker), it automatically stops to protect its human colleagues. These features aren’t present on industrial robots, and they’re the reason why force limited robots can work alongside humans without any fencing. Regular industrial robots must be isolated because they neither feel nor monitor their environment. Force limited robots also tend to have rounder shapes than regular industrial robots. This means they cause less harm when they collide with something else. A round shape spreads the force over a bigger surface area and reduces the pressure applied to an external object (or person). Some force limited robots even have cushioned shells that absorb shocks and reduce the effect of deceleration on a human body part, which results in a less harmful impact.


“Cobot” is a slang term used to describe a collaborative robot. Once again, the term “cobot” is mostly used when talking about force limited robots. So you can basically say that a force limited robot is a cobot. While an industrial robot can be used for collaborative tasks, it’s usually not force limited, and these types of robots tend to need supplementary monitoring devices in order for them to safely execute tasks alongside humans.


     1- Payload

     2- Robot weight

     3- Repeatability

     4- Safety

     5- Intuitive programming

     6- Reach


The reason the power and force limiting cobot is common is that of its ability to sense and stop forces which help to avoid human injuries. This is because of the numerous sensors in them. The main difference between the power and force limiting cobot and the other 3 types is because the power and force limiting cobot has the ability to make use of the normal robots using additional sensors and still maintain their safety standards with regards to working with humans. It is always ideal to take your time to learn about the different types of cobots in the market before you settle on one.

Here are the different types of collaborative robots:

Joint sensing

This is the most common force limited cobot type. This type of robots include robots manufactured by universal robots and KUKA. The joint sensing cobots make use of the joints for force monitoring on the robot’s body. Some robots can monitor forces using motor currents or force-torque sensors attached to their joints. This makes joint sensing cobots the nest choice for human interaction. This is because they simply need to be programmed to run safely and effectively.

Force sensor base cobots

This is a type of force limited cobot which uses a different way to connect with the forces applied to it. It makes use of a force-torque sensor that is connected to the robot’s base to be able to monitor forces. This means that, for example, if the cobot is programmed to perform a task towards one direction, it will stop if they come across an obstacle as the force sensor will sense the presence of an abnormal force vector. This is a technique mostly used by industries that turn their industrial robots into collaborative robots.

The benefit of this is that manufacturers can enjoy the convenience of a large robot with better sensitivity to force. This means that it is possible to have a robot that can handle a load of 35kgs and still have the ability to react to minimum impacts. Even so, it is important for you to see the payload accurately to enable the robot to gauge whether the force applied to the force sensor is higher than what it can handle. This makes force sensor based cobots are more complicated in terms of use as compared to the joint sensing cobots.

Skin sensing cobots

This is not too common in the industry yet. However, it is termed as the safest option so far. Robots such as Bosch make use of different types of tactile sensing to recognize the eventual impact. This sensor will monitor the robot’s body conductivity to communicate with the robot to stop whenever it reaches a predetermined threshold. The skin sensing cobots are seen as complex solutions for most manufacturers but can be safe for the end-user. This robot keeps impacts at a minimum, even with the ability to sense when it is almost colliding with something.

Inherently safe cobots

These are types of collaborative robots that make use of all types of sensors. They are set apart by the fact that they are completely harmless to humans. This is because these robots do not have the power to do any kind of damage. Even so, it still needs to be programmed to avoid accidents. Even so, there are minimal ways a user can hurt themselves with this collaborative robot.


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Robots are primarily differentiated based on two categories:  USE AND MOVEMENT


ROBOT DESIGN | 7 robots differentiation by locomotion:

Each of these different categories of robots contains machines of all shapes and sizes. One thing that’s true across the entire field of robotics is that a robot’s appearance will often be informed by the way it moves through the it’s environment.

Types of robots by locomotion:
1- Stationary robots
2- Swarm Robots
3- Wheeled Robots
4- Nano Robots
5- Legged Robots
6- Swimming Robots
7- Flying Robots


ROBOT DESIGN | 6 robots differentiation by use:

There is a great deal of overlap in many of these categories; drones, for example, can be classified as either aerospace, consumer, or exploration. Here we have 6 relevant types of robots based on Mr. Piper Thomson’s estimation of what the intent of development is for each particular device.

1- Industrial robots

Industrial robots often comprise the most basic form of machine — a stationary or semi-stationary device that executes a repetitive task. These robots are generally some of the least intelligent due to the fact that the work they do is incredibly simple and the environments in which they work are fairly free of external influences that could disrupt their routines.

2- Exploration robots

These cybernetic adventurers can range in complexity from simple probes to fully autonomous spacecraft. They are used to explore the farthest reaches of space and the darkest trenches of the ocean floor, boldly going where no man has gone before.

mars roverSome of the more famous examples of these, such as the Mars Rover Opportunity, are a type of robot known as ‘Remotely Operated Vehicle’ (or ROV) that performs some autonomous functions while having the capability of being operated by a remote operator or pilot. These robots typically come equipped with advanced observation or manipulation features. These features allow them to gather data from their assigned environments in a more focused way than their less complex aerospace cousins.

3- Consumer robots

Consumer robots are so commonplace that many people fail to see them as robots at all! These are the little household helpers that unobtrusively improve the lives of countless homeowners the world over. The classic example of a consumer robot is the roomba, an autonomous cleaning machine complete with sensors to help it navigate any space you put it in.
More recently, simplistic AI has started to fuse with consumer robots and the internet of things to give us devices such as the Amazon Alexa or Google Home. These stationary robots come equipped with what’s referred to as a ‘conversational AI’ that can read things such as tone and context to make an educated guess as to the intent of the speaker. While these devices are still far from perfect, it’s exciting to imagine the quality of life they could provide us in the next half century.

4- Medical robots

Aside from production, exploration, and menial tasks, robots can also be literal lifesavers. Medical robots can range from autonomous arms that help surgeons perform delicate operations to the emerging field of mind-controlled robotic prosthetics and exoskeletons. While we probably won’t see fully autonomous surgeons for many years to come, doctor-operated robots have pushed the boundaries of medicine in terms of what can be accomplished without having to resort to risky invasive procedures. Devices such as the daVinci system have made it possible to perform dangerous operations with a fraction of the normal risk.

5- Aerospace robots

Aerospace robots are, in some capacity, able to fly. They differ from exploration robots in that they don’t include aquatic automatons or surface rovers. Common forms of these robots are autonomous or remote controlled drones or spacecraft that can be used for a variety of purposes such as research, military intelligence, or deep space exploration.

6- Aquatic Robots

Aquatic robots go far beyond deep-sea exploration. They can work with the coast guard as unmanned boats and have often been used by marine biologists and conservationists to help supplement parts of marine ecosystems that have been ravaged by climate change and industrialization efforts like off-shore drilling. Interestingly, Aquatic robotics is also one of the subfields at the forefront of biorobotics, where the robots developed take inspiration from organic animals in the wild for how they move. Many researchers have found great success with modeling their swimming robots off of common underwater species such as fish or eels, whose innate abilities to navigate the underwater seascape is far superior to traditional methods of locomotion for human-made sea-craft.

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