Building a robot or a robotic prototype is unimaginable without sensors. Sensors give a robot the ability to understand its surroundings and itself better. Because of this, sensor installation will play a major role in determining the accuracy and precision of your robotic application.
This guide explores some of the common mistakes you can avoid when installing sensors in your robots.
Sensor selection is quite more complex than you may think. With many sensors available, it can get tricky to determine the correct sensor type that will meet your application requirements. For example, if your objective is to measure the light intensity, you can choose between phototransistors, photoresistors, and photodiodes. So, which one should you choose?
While phototransistors cost less, they’re insensitive to incident light coming from other directions compared to photoresistors. On the other hand, photoresistors are more temperature-sensitive and bulky in size in contrast to phototransistors and photodiodes.
Selecting the wrong sensor for your application will likely give you erroneous results. Hence, the first step is to clearly define the requirements of your robotic application, compare the sensor capabilities, and select a sensor that best meets the requirements.
Sensor placement is critical to get accurate readings. If you offset the sensor from its correct installation point, it will adversely affect the accuracy of readings.
For example, proximity sensors measure the distance between the sensors and an object in front of it. Usually, this sensor is placed at the outermost part of the robot so that the distance-till-collision can be measured accurately. If the sensor placement is wrong, the robot will have difficulty sensing objects near its structure and increase the chances of collision.
Similarly, if your application also involves using a pressure sensor, it needs to be set at different orientations to collect accurate force information. Likewise, an ultrasonic level sensor should be perpendicular to the target to get accurate measurements. Another example is a temperature sensor. You need to place the sensor at a point where the temperature readings are more consistent. If a spot goes through temperature fluctuations, the readings may lead to false triggers.
A light sensor is another good example that works best when placed perpendicular to the source of light. In some applications, the direction of light can vary–and in such cases–multiple light sensors are used to get the best results.
Apart from considering the sensor orientations, you should also always refer to the manufacturer-provided installation and setup guide to ensure accuracy in readings.
Depending on whether your application is indoors or outdoors, the sensors may require operating in harsh conditions. In such cases, it is critical to provide adequate protection to the sensors to prevent damage while also collecting accurate data.
There are several rugged sensors available today that can operate efficiently in harsh environments while producing accurate results.
Despite installing the sensor correctly and placing it in the right position, it may produce erroneous results. If you’re experiencing a similar situation, the chances are that the sensor data is influenced by outside factors in the form of noise. This noise is nothing but unwanted signals that get picked up by sensors, affecting the actual readings.
When installing a new sensor, you must factor in this noise and make necessary arrangements to keep the noise to zero or as low as possible. Usually, ground loops and RFI (Radio Frequency Interference) are the two main sources of noise. However, even a normal household current oscillating at 60hz can interfere with the sensor readings.
With shielding, it is possible to protect the sensors from this noise. You can also remove the factors that produce noise from the vicinity of the sensor. Filtering is another method that you can use to clean out the noise from the actual signals.
Getting the installation right is critical to ensure that your sensors are working accurately, and eventually, ensuring that your robotic application functions as per the plan. Get in touch with sensor technology experts at Hokuyo to get assistance in sensor selection and installation.
At Hokuyo, we offer a wide range of sensors to OEMs, end-users, integrators, and R&D firms involved in autonomous robotics applications. Our robust LiDAR sensors and optical sensors are a few among the vast array of high-quality sensors we manufacture.