Accuracy Evaluation of Selected Mobile Inspection Robot Localization Techniques in a GNSS-Denied Environment

Abstract

Locating an inspection robot is an essential task for inspection missions and spatial data acquisition. Giving a spatial reference to measurements, especially those concerning environmental parameters, e.g., gas concentrations may make them more valuable by enabling more insightful analyses. Thus, an accurate estimation of sensor position and orientation is a significant topic in mobile measurement systems used in robotics, remote sensing, or autonomous vehicles. Those systems often work in urban or underground conditions, which are lowering or disabling the possibility of using Global Navigation Satellite Systems (GNSS) for this purpose. Alternative solutions vary significantly in sensor configuration requirements, positioning accuracy, and computational complexity. The selection of the optimal solution is difficult. The focus here is put on the assessment, using the criterion of the positioning accuracy of the mobile robot with no use of GNSS signals. Automated geodetic surveying equipment is utilized for acquiring precise ground truth data of the robot’s movement. The results obtained, with the use of several methods, compared: Wheel odometry, inertial measurement-based dead-reckoning, visual odometry, and trilateration of ultra-wideband signals. The suitability, pros, and cons of each method are discussed in the context of their application in autonomous robotic systems, operating in an underground mine environment.

A review study on unmanned aerial vehicle and mobile robot technologies on damage inspection of reinforced concrete structures

“…More research focusing on the techniques and applications related to the mobile robot-based platform for structural damage inspection and various purposes has been widely conducted as presented in Table 3, such as non-structural damage inspection, 94 pipeline inspection, 95,96 localization techniques of inspection-aimed mobile robots. 97 These previous studies demonstrated that increasing attention is paid to mobile robot technology which can be applied in practice for damage inspection in various scenarios, and is able to perform more tasks, such as repair of pipelines. However, only a few studies of using mobile robot technology in damage inspection of building structures have been found, which indicates the potential to explore the feasibility of mobile robots for collecting data and inspecting the damage to buildings, as well as to evaluate their performance and application prospect in the practice.…”

Accelerometer-Based Wheel Odometer for Kinematics Determination

“…Whereas the additional radial component can be written as shown in Equation (6). In Equation (6), the radial acceleration component is equivalent to the product of the radius ( ) at which the accelerometer is mounted on the wheel and the squared angular rate ( ) of the spinning wheel.…”

“…The radial acceleration component is caused due to an eccentricity ( ) in mounting the AWOK IMU to the wheel, where the centroid of the IMU does not coincide with the wheel center. Hence, by using the formula shown in Equation (6), that radial acceleration component increases quadratically with the angular rate of the wheel ( ). Consequently, the superimposed radial acceleration trend can be computed using Equation (6).…”

“…Hence, by using the formula shown in Equation (6), that radial acceleration component increases quadratically with the angular rate of the wheel ( ). Consequently, the superimposed radial acceleration trend can be computed using Equation (6). Nonetheless, it can be beneficial to have a representation of the angular acceleration of the wheels, from which the vehicle speed can be derived.…”

“…Typically, cars navigate the urban environment, which hinders the performance of Global Navigation Satellite Systems (GNSS) due to multipath errors and signal blockage within urban canyons. Consequently, the GNSS is integrated with inertial measurement units (IMUs) to remedy the problem of GNSS signal degradation and/or blockage [2,6]. However, low-cost automotive-grade IMUs endure a multitude of long-term stochastic errors.…”