Ultrasonic sensors allow us to equip robots with a means of perceiving surrounding objects, an alternative to technical vision. Humanoid robots, like robots of other types, are, first, equipped with sensory systems similar to the senses of a human. However, this approach is not enough. All possible types and kinds of sensors should be used, including those that are similar to those of other animals and creations (in particular, echolocation in dolphins and bats), as well as sensors that have no analogues in the wild. This paper discusses the main issues that arise when working with the HC-SR04 ultrasound rangefinder based on the STM32VLDISCOVERY evaluation board. The characteristics of similar modules for comparison are given. A subroutine for working with the sensor is given.

https://iopscience.iop.org/article/10.1088/1742-6596/1015/3/032189/pdf

Application of ultrasonic sensor for measuring distances in robotics

Autonomous vehicles (AVs) must share space with pedestrians, both in carriageway cases such as cars at pedestrian crossings and off-carriageway cases such as delivery vehicles navigating through crowds on pedestrianized high-streets. Unlike static obstacles, pedestrians are active agents with complex, interactive motions. Planning AV actions in the presence of pedestrians thus requires modelling of their probable future behavior as well as detecting and tracking them. This narrative review article is Part I of a pair, together surveying the current technology stack involved in this process, organising recent research into a hierarchical taxonomy ranging from low-level image detection to high-level psychology models, from the perspective of an AV designer. This self-contained Part I covers the lower levels of this stack, from sensing, through detection and recognition, up to tracking of pedestrians. Technologies at these levels are found to be mature and available as foundations for use in high-level systems, such as behavior modelling, prediction and interaction control.

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Pedestrian Models for Autonomous Driving Part I: Low-Level Models, From Sensing to Tracking

Over the last decade, Unmanned Aerial Vehicles (UAVs), also known as drones, have been broadly utilized in various agricultural fields, such as crop management, crop monitoring, seed sowing, and pesticide spraying. Nonetheless, autonomy is still a crucial limitation faced by the Internet of Things (IoT) UAV systems, especially when used as sprayer UAVs, where data needs to be captured and preprocessed for robust real-time obstacle detection and collision avoidance. Moreover, because of the objective and operational difference between general UAVs and sprayer UAVs, not every obstacle detection and collision avoidance method will be sufficient for sprayer UAVs. In this regard, this article seeks to review the most relevant developments on all correlated branches of the obstacle avoidance scenarios for agricultural sprayer UAVs, including a UAV sprayer’s structural details. Furthermore, the most relevant open challenges for current UAV sprayer solutions are enumerated, thus paving the way for future researchers to define a roadmap for devising new-generation, affordable autonomous sprayer UAV solutions. Agricultural UAV sprayers require data-intensive algorithms for the processing of the images acquired, and expertise in the field of autonomous flight is usually needed. The present study concludes that UAV sprayers are still facing obstacle detection challenges due to their dynamic operating and loading conditions.

https://www.mdpi.com/2073-4395/11/6/1069/pdf

A State-of-the-Art Analysis of Obstacle Avoidance Methods from the Perspective of an Agricultural Sprayer UAV’s Operation Scenario

Smart farming is a development that has emphasized information and communication technology used in machinery, equipment, and sensors in network-based hi-tech farm supervision cycles. Innovative technologies, the Internet of Things (IoT), and cloud computing are anticipated to inspire growth and initiate the use of robots and artificial intelligence in farming. Such ground-breaking deviations are unsettling current agriculture approaches, while also presenting a range of challenges. This paper investigates the tools and equipment used in applications of wireless sensors in IoT agriculture, and the anticipated challenges faced when merging technology with conventional farming activities. Furthermore, this technical knowledge is helpful to growers during crop periods from sowing to harvest; and applications in both packing and transport are also investigated. 

/pdf/smart-farming-internet-of-things-iot-based-sustainable-1zhlg9gd.pdf

Smart Farming: Internet of Things (IoT)-Based Sustainable Agriculture

Today, low-cost sensors in various civil engineering sectors are gaining the attention of researchers due to their reduced production cost and their applicability to multiple nodes. Low-cost sensors also have the advantage of easily connecting to low-cost microcontrollers such as Arduino. A low-cost, reliable acquisition system based on Arduino technology can further reduce the price of data acquisition and monitoring, which can make long-term monitoring possible. This paper introduces a wireless Internet-based low-cost data acquisition system consisting of Raspberry Pi and several Arduinos as signal conditioners. This study investigates the beneficial impact of similar sensor combinations, aiming to improve the overall accuracy of several sensors with an unknown accuracy range. The paper then describes an experiment that gives valuable information about the standard deviation, distribution functions, and error level of various individual low-cost sensors under different environmental circumstances. Unfortunately, these data are usually missing and sometimes assumed in numerical studies targeting the development of structural system identification methods. A measuring device consisting of a total of 75 contactless ranging sensors connected to two microcontrollers (Arduinos) was designed to study the similar sensor combination theory and present the standard deviation and distribution functions. The 75 sensors include: 25 units of HC-SR04 (analog), 25 units of VL53L0X, and 25 units of VL53L1X (digital). 

/pdf/low-cost-sensors-accuracy-study-and-enhancement-strategy-1q8npduv.pdf

Low-Cost Sensors Accuracy Study and Enhancement Strategy

This paper solves the problem of designing of regulator for control of complex unstable object. Calculation was done by numerical optimization using control structure comprising bypass channel. The idea of the bypass channel develops the idea of Smith predictor, but, unlike a predictor, its model can be calculated by the more flexible algorithms. Furthermore, this method does not require the presence of a pure delay link in the object model. This makes the bypass channel more flexible and more efficient than a Smith predictor. The object model is taken from list of well-known object models, which are very difficult for the feedback control due to the strong tendency to fluctuations. Earlier attempts to design regulators for this object are unsatisfactory. This paper shows the efficiency of the bypass channel for the said task. The results are confirmed by simulation.

The use of bypass channel for feedback control of oscillatory object well-known as difficult one for control

This paper performs determination of a mathematical model of the balancing robot, its linearization and algorithm for calculation of stabilization of the deflection angle from the vertical modal method. This algorithm also makes determination of the angle of deviation from the use of either alpha-beta filter and the angle of rotation of the wheels by means of encoders.

/pdf/development-of-deflection-angle-stabilizing-system-for-nk9dc4v8l0.pdf

Development of Deflection Angle Stabilizing System for Balancing Robot

This paper studies the mathematical model of the object "inverted pendulum" on the example of the unstable electromechanical device — balancing robot on the wheel pair. The paper gives the results of analysis of the impact of many real control object properties on the system performance. Among them the most important ones are the actuator, filters, friction and the tendency to fluctuations.

Detection of unrevealed non-linearities in the layout of the balancing robot

This article is devoted to issues concerned with the task of stabilization of two wheeled balancing robot in a vertical position. This device is an inverted pendulum type object from the mathematical point of view. The key aspects of stabilization task are researched. The operation of the tilt angle estimation subsystem based on using accelerometer and gyro sensors is researched. The operation of the complementary filter used for fusing sensors data is considered. It is shown that this filter has a weakness which consists in that the accelerometer mid- and low-frequency distortions may go through the filter. The alternate technique of tilt angle estimation is proposed. This method is based on implicit using the encoder data which is used to estimate wheel rotation angle. The structure of the control system used this approach is given and the controller coefficients equations are presented. The issue of desired dynamics polynomial selection is considered. Finally the simulation and the real device operation result are shown.

Vitaly Trubin

Papers

Application of ultrasonic sensor for measuring distances in robotics

The use of bypass channel for feedback control of oscillatory object well-known as difficult one for control

Development of Deflection Angle Stabilizing System for Balancing Robot

Detection of unrevealed non-linearities in the layout of the balancing robot

The tilt angle estimation in the inverted pendulum stabilization task