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Force sensing is less popular than vision systems, although it is as useful as vision, and sometimes more so.

For many years, industrial robots have not been able to monitor their surroundings. As more and more different sensors are introduced to robots, they can now "feel" what they are dealing with, and "see" what they are doing or who is around them. However, force sensing is less popular than vision systems, even though it is as useful as vision, and sometimes even more so. The vision system is powerful, but it cannot solve all problems and is expensive. Let's take a look at the applications in which force sensors can complete the vision system, saving you money and practicality.

Force sensing can be obtained through the force sensor embedded in the robotic arm, and most of the collaborative robots on the market already have it. I've embedded force feedback loops on Universal Robots and they do what I want. The only downside to using a built-in force sensor is that you don't have a device with the same accuracy that can "read" the force. Most built-in force sensors measure force by reading the robot's current. Of course, some force sensors use other methods, such as determining the magnitude of the force exerted on them based on the deformation of the material.

1. Constant force

Torque sensors were first manufactured for grinding, polishing and other applications. Since these applications are difficult to automate, the robot needs some force feedback to determine if it's pushing hard enough.

You can easily automate these applications by introducing force feedback loops into your programs, enabling consistent manufacturing processes. In this case, you need to use an external device rather than an embedded solution from the robot manufacturer.

2. Target positioning

We often come across customers who generally believe that the only way to locate and quantify parts is to use vision sensors. But actually this is not the only solution. Admittedly, vision systems are a great way to locate or quantify parts, but it’s also possible to use force sensors to find and inspect parts. It's one thing to figure out where they are on the X-Y plane, it's another thing to figure out what altitude they're at. In fact, to do this, a 3D vision system is required. If it's a pile of objects, you don't need to know the exact tree of the whole pile of objects, you just need to look in that pile every time. The robot just needs to determine the height of the pile of objects, and then continuously adjust its grasping height.

Another search function that uses a force sensor is the "free mode" of the sensor. It is possible that the parameters of the FT sensor were not fully utilized. "Free Mode" or "Zero Gravity" mode will let you "liberate" the robot's axes, which will allow it to improve its compliance. For example, if you want to tighten a part on a CNC machine, you can free up 2 axes to allow the part to close perfectly while still maintaining some grip. This allows the force to act entirely on the center of the part, with no additional force acting on the robot's axis.

3. Repetitive force

If you're considering a robot for assembly tasks, you want the robot to be able to repeat the same task over and over. However, one of the reasons assembly tasks are difficult to automate is that they require an operator to perform force detection. By introducing the FT sensor, you can feel the external force applied during the assembly process.

Robots need to apply very precise forces when putting batteries on their phones. Since these parts are easily damaged, it is really difficult to assemble them intact. This is why a very low force threshold is set to prevent misalignment and damage of components.

4. Weigh things

The application above is to separate the orange and blue pucks. However, the way we do it has nothing to do with their color. Actually, it has to do with their weight. Orange pucks are heavier than blue pucks, and sensors can tell them apart based on their weight.

This can also be used to distinguish different parts that are similar in shape. However, in real life, knowing if you have the right object in your gripper, or if an object has fallen, is very helpful and can really help you in your production pipeline. A torque sensor can do this easily.

5. Manual guidance

Most collaborative robots are manually guided by using built-in FT sensors, but traditional industrial robots do not have built-in sensors of this type. This is why your traditional industrial robot needs an FT sensor. With it, you can guide the teach pendant manually without using a teach pendant. As long as one FT sensor is required, the teaching of the robot can be completed by setting the start and end points of the robot, and the linear trajectory in the middle.

As you can see, force feedback is very useful and can be used in many different applications. Analyze your workflow to see if a force sensor can be used instead of a vision system. Most of the time, force sensors are easier to integrate, you don't need an integrator, you can do it yourself.

What is a robot

A robot is a mechanical device that performs work automatically. It can accept human command, run pre-programmed programs, or act according to principles and programs formulated with artificial intelligence technology. Its task is to assist or replace human jobs, such as production, construction, or dangerous jobs.

What is an industrial robot

Industrial robots are multi-joint manipulators or multi-degree-of-freedom robots for the industrial field. An industrial robot is a machine device that automatically performs work, and is a machine that realizes various functions by its own power and control capabilities. It can be commanded by humans or run according to pre-arranged programs. Modern industrial robots can also act according to the principles and programs formulated by artificial intelligence technology.