Low Cost Autonomous Driving Architecture using Ultrasonic Sensors and Camera

Curb detection and localization systems constitute an important aspect of environmental recognition systems of autonomous driving vehicles. This is because detecting curbs can provide information about the boundary of a road, which can be used as a safety system to prevent unexpected intrusions into pedestrian walkways. Moreover, curb detection and localization systems enable the autonomous vehicle to recognize the surrounding environment and the lane in which the vehicle is driving. Most existing curb detection and localization systems use multichannel light detection and ranging (lidar) as a primary sensor. However, although lidar demonstrates high performance, it is too expensive to be used for commercial vehicles. In this paper, we use ultrasonic sensors to implement a practical, low-cost curb detection and localization system. To compensate for the relatively lower performance of ultrasonic sensors as compared to other higher-cost sensors, we used multiple ultrasonic sensors and applied a series of novel processing algorithms that overcome the limitations of a single ultrasonic sensor and conventional algorithms. The proposed algorithms consisted of a ground reflection elimination filter, a measurement reliability calculation, and distance estimation algorithms corresponding to the reliability of the obtained measurements. The performance of the proposed processing algorithms was demonstrated by a field test under four representative curb scenarios. The availability of reliable distance estimates from the proposed methods with three ultrasonic sensors was significantly higher than that from the other methods, e.g., 92.08% vs. 66.34%, when the test vehicle passed a trapezoidal-shaped road shoulder. When four ultrasonic sensors were used, 96.04% availability and 13.50 cm accuracy (root mean square error) were achieved.

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Design and Development of a Low Cost, Non-Contact Infrared Thermometer with Range Compensation

Sensors ◽

10.3390/s21113817 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3817

Author(s):

Nicholas Wei-Jie Goh ◽

Jun-Jie Poh ◽

Joshua Yi Yeo ◽

Benjamin Jun-Jie Aw ◽

Szu Cheng Lai ◽

...

Keyword(s):

Measurement Accuracy ◽

Low Cost ◽

Common Symptom ◽

Ultrasonic Sensors ◽

Design And Development ◽

Infrared Thermometer ◽

Compensation Methods ◽

Monitoring Devices ◽

Distance Correction

Fever is a common symptom of many infections, e.g., in the ongoing COVID-19 pandemic, keeping monitoring devices such as thermometers in constant demand. Recent technological advancements have made infrared (IR) thermometers the choice for contactless screening of multiple individuals. Yet, even so, the measurement accuracy of such thermometers is affected by many factors including the distance from the volunteers’ forehead, impurities (such as sweat), and the location measured on the volunteers’ forehead. To overcome these factors, we describe the assembly of an Arduino-based digital IR thermometer with distance correction using the MLX90614 IR thermometer and HC-SR04 ultrasonic sensors. Coupled with some analysis of these factors, we also found ways to programme compensation methods for the final assembled digital IR thermometer to provide more accurate readings and measurements.

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Robustness against Chirp Signal Interference of On-Board Vehicle Geodetic and Low-Cost GNSS Receivers

Sensors ◽

10.3390/s21165257 ◽

2021 ◽

Vol 21 (16) ◽

pp. 5257

Author(s):

Franc Dimc ◽

Polona Pavlovčič-Prešeren ◽

Matej Bažec

Keyword(s):

Interference Mitigation ◽

Low Cost ◽

Density Ratio ◽

Autonomous Driving ◽

Signal Interference ◽

Noise Power ◽

Reference Base ◽

Noise Power Spectral Density ◽

Processing Abilities ◽

Gnss Receivers

Robust autonomous driving, as long as it relies on satellite-based positioning, requires carrier-phase-based algorithms, among other types of data sources, to obtain precise and true positions, which is also primarily true for the use of GNSS geodetic receivers, but also increasingly true for mass-market devices. The experiment was conducted under line-of-sight conditions on a straight road during a period of no traffic. The receivers were positioned on the roof of a car travelling at low speed in the presence of a static jammer, while kinematic relative positioning was performed with the static reference base receiver. Interference mitigation techniques in the GNSS receivers used, which were unknown to the authors, were compared using (a) the observed carrier-to-noise power spectral density ratio as an indication of the receivers’ ability to improve signal quality, and (b) the post-processed position solutions based on RINEX-formatted data. The observed carrier-to-noise density generally exerts the expected dependencies and leaves space for comparisons of applied processing abilities in the receivers, while conclusions on the output data results comparison are limited due to the non-synchronized clocks of the receivers. According to our current and previous results, none of the GNSS receivers used in the experiments employs an effective type of complete mitigation technique adapted to the chirp jammer.

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Design of Mechaless LiDAR Optical System With Large FOV Using Liquid Lens and Fisheye Lens

ASME-JSME 2018 Joint International Conference on Information Storage and Processing Systems and Micromechatronics for Information and Precision Equipment ◽

10.1115/isps-mipe2018-8517 ◽

2018 ◽

Author(s):

Hyun Choi ◽

Wan-Chin Kim

Keyword(s):

Low Cost ◽

Autonomous Driving ◽

Voltage Regulation ◽

Field Of View ◽

Fisheye Lens ◽

Liquid Lens ◽

Fine Spatial Resolution ◽

Flash Lidar ◽

Optical Phased Array ◽

Measurable Distance

Mechaless LiDAR technology, which does not have a mechanical drive part, has been actively studied in order to increase the reliability of the LiDAR device at low cost and drive environment in order to more actively apply LiDAR technology to autonomous driving. Mechaless LiDAR technology, which has been mainly studied recently, includes 3D Flash LiDAR technology, MEMS mirror utilization method, and OPA (Optical Phased Array). However, these methods have not been developed rapidly as a key technology for achieving autonomous driving due to low stability of driving environment or remarkably low measurable distance and FOV (field of view) compared with mechanical LiDAR. In this study, we investigated the improvement of FOV by using a flux-deflecting liquid lens and a fisheye lens that can achieve fine spatial resolution through continuous voltage regulation. Based on the initial design results, it was examined that the FOV can be secured to 80 ° or more by utilizing a relatively simple fisheye lens composed of only spherical lenses.

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Performance Evaluation of Autonomous Driving Control Algorithm for a Crawler-Type Agricultural Vehicle Based on Low-Cost Multi-Sensor Fusion Positioning

Applied Sciences ◽

10.3390/app10134667 ◽

2020 ◽

Vol 10 (13) ◽

pp. 4667 ◽

Cited By ~ 1

Author(s):

Joong-hee Han ◽

Chi-ho Park ◽

Jay Hyoun Kwon ◽

Jisun Lee ◽

Tae Soo Kim ◽

...

Keyword(s):

Control Algorithm ◽

Low Cost ◽

Autonomous Driving ◽

Maximum Error ◽

Sensor Technology ◽

Motion Sensor ◽

Integration Algorithm ◽

Sensor Module ◽

Agricultural Vehicle ◽

Mean Square Errors

The agriculture sector is currently facing the problems of aging and decreasing skilled labor, meaning that the future direction of agriculture will be a transition to automation and mechanization that can maximize efficiency and decrease costs. Moreover, interest in the development of autonomous agricultural vehicles is increasing due to advances in sensor technology and information and communication technology (ICT). Therefore, an autonomous driving control algorithm using a low-cost global navigation satellite system (GNSS)-real-time kinematic (RTK) module and a low-cost motion sensor module was developed to commercialize an autonomous driving system for a crawler-type agricultural vehicle. Moreover, an autonomous driving control algorithm, including the GNSS-RTK/motion sensor integration algorithm and the path-tracking control algorithm, was proposed. Then, the performance of the proposed algorithm was evaluated based on three trajectories. The Root Mean Square Errors (RMSEs) of the path-following of each trajectory are calculated to be 9, 7, and 7 cm, respectively, and the maximum error is smaller than 30 cm. Thus, it is expected that the proposed algorithm could be used to conduct autonomous driving with about a 10 cm-level of accuracy.

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Energy Efficiency Due to a Common Global Timebase—Synchronizing FlexRay to 802.1AS Networks as a Foundation

Journal of Low Power Electronics and Applications ◽

10.3390/jlpea8030026 ◽

2018 ◽

Vol 8 (3) ◽

pp. 26

Author(s):

Paul Milbredt ◽

Efim Schick ◽

Michael Hübner

Keyword(s):

Time Synchronization ◽

Fault Tolerant ◽

Low Cost ◽

Autonomous Driving ◽

Consumer Electronics ◽

Area Network ◽

Control Applications ◽

Synchronization Mechanism ◽

Global Clock ◽

Time And Energy

Modern automotive control applications require a holistic time-sensitive development. Nowadays, this is achieved by technologies specifically designed for the automotive domain, like FlexRay, which offer a fault-tolerant time synchronization mechanism built into the protocol. Currently, the automotive industry adopts the Ethernet within the car, not only for embedding consumer electronics, but also as a fast and reliable backbone for control applications. Still, low-cost but highly reliable sensors connected over the traditional Controller Area Network (CAN) deliver data needed for autonomous driving. To fusion the data efficiently among all, a common timebase is required. The alternative would be oversampling, which uses more time and energy, e.g., at least double the perception rates of sensors. Ethernet and CAN do require the latter by default. Hence, a global synchronization mechanism eases tremendously the design of a low power automotive network and is the foundation of a transparent global clock. In this article, we present the first step: Synchronizing legacy FlexRay networks to the upcoming Ethernet backbone, which will contain a precise clock over the generalized Precision Time Protocol (gPTP) defined in IEEE 802.1AS. FlexRay then could still drive its strengths with deterministic transmission behavior and possibly also serve as a redundant technology for fail-operational system design.

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