This paper presents an enhanced fault-tolerant architecture for industrial Networked Control Systems (NCS) that simultaneously supports supervision video transmission and maintains strict real-time constraints. Building upon previous work that optimized video and control data flows through static traffic management techniques, this study introduces approaches to address fault tolerance and scalability challenges. First, supervision video enhanced quality operating up to the standard 50 frames per second (fps) was tested. Second the use of Field Programmable Gate Array (FPGA) resources embedded within the core network switch to handle controller fault recovery locally is proposed and tested. The use of this FPGA-enhanced architecture effectively isolates control and video traffic, ensuring real-time responsiveness even with supervisory cameras operating at high frame rates. Simulation results confirm maximum delays in faulty scenarios, well within the real-time requirements. The proposed solutions demonstrate possible scalable methods for integrating fault tolerance and high-quality video supervision in modern industrial NCS, with the FPGA-based design offering latency improvements of 7.58% over previously studied designs.

Advanced Driver Assistance Systems (ADAS) are being thoroughly researched nowadays especially in the field of autonomous vehicles. However, motorcycles and Advanced Rider Assistance Systems (ARAS) have not yet received the same level of attention. This paper is an attempt to address some of the problems encountered by motorcycle riders in urban areas, namely obstacle detection and alerting the rider if vehicles behind him/her are travelling at an illegally high speed. The proposed system uses a fusion algorithm that combines readings from two LiDAR sensors, one on the motorcycle and the other in the rider’s helmet. Additionally, two cameras are fixed on the motorcycle, one facing forward and the other facing backwards. YOLO, Ultra-Fast Lane Detection network and sensor front/rear sensor fusion are then used to reach a reliable decision to alert the rider of a potential danger and to advise him/her regarding the most appropriate maneuver to avoid the danger.

Fault-Tolerant (FT) architectures are often used in the context of Industrial Automation, especially in safety-critical systems. Coverage is a very important parameter; it measures the ability of these systems to detect and recover from expected failures. This paper investigates the effect of changes in the value of the Coverage parameter on the steady state availability of several commonly used FT architectures, namely Triple Modular Redundancy (TMR), Sift-Out and Reconfigurable Duplication. When comparing TMR and Sift-Out, it is found that, at relatively low values of coverage, adding redundancy will reduce availability and increase downtime; this is a counter intuitive result. For Reconfigurable Duplication, it is found that, at low Mean Time To Repair (MTTR), the effect of small changes in coverage has little effect on architecture availability. Hence, it is preferable to invest in the quality of the system's redundant modules instead of the quality of the error detection and recovery mechanisms. In contrast, at higher MTTRs, a small increase in the coverage affects availability; hence, investing in the quality of error detection will lower downtime and decrease profit loss.

Unmanned Aerial Vehicles (UAVs) are quickly becoming a very important component in many applications, such as search and rescue. In many of these applications, Deep Neural Networks (DNNs) are used, especially for obstacle detection and avoidance. Furthermore, online retraining may be required for adaptation to new environments. This paper shows how to enable UAVs equipped with an FPGA-based controller to achieve the required accuracy, whether in the inference phase or in the retraining phase, with minimal impact on power and performance. Dynamic Function eXchange (DFX) is used to download the retraining module bitstream utilizing Posit16 multipliers when the UAV navigates a new environment. Otherwise, a Posit8 multiplier (lower in precision) based implementation is used for the inference procedure that requires less precision than the retraining procedure. An implementation on the EP4CE22F17C6 FPGA is presented to show that a Posit16 multiplier has very close power utilization and performance to that of a Posit8 multiplier.

This paper addresses the issue of analog sensor reliability in the context of Advanced Driver Assistance Systems (ADAS) in the automotive industry. Nowadays, many vehicles use two sensors for error detection. Two fail-safe and fault-tolerant architectures are proposed to increase sensor lifetime at a low cost. One of these architectures is proven to be more reliable and of a lower cost than a conventional Triple Modular Redundant (TMR) system. Both designs rely on a tunable TMR detection mechanism to process the analog outputs of three functionally equivalent sensors taking into account the unavoidable discrepancies after the Analog-to-digital conversion. This hardware error detection mechanism will reduce the processing time of the sensor data compared to a software scheme. The mechanism is implemented on Intel Cyclone IV GX EP4CGX150DF31I7AD FPGA; circuit delay and resource utilization are obtained. Finally, this circuit delay is compared to the execution time of a functionally equivalent software implemented on a NIOS II processor.

Object detection under a vehicle's undercarriage is receiving a lot of attention nowadays. This paper proposes a system to detect objects under a stationary vehicle, whether the object is on the ground or attached to the undercarriage. Sensor fusion is used to increase system accuracy. Ultrasonic sensors as well as a LiDAR are used in the proposed system. Fusion is performed at the individual sensor level first then data from both types of sensors is fused together to accurately detect and locate a potential object. Experiments were successfully conducted using a HC-SR04 ultrasonic sensor and a TFmini LiDAR. A flexible system is then proposed that can be tuned to the characteristics of other types of ultrasonic sensors and LiDARs.

A fault-tolerant Wi-Fi-based architecture for a Modular Prosthetic Limb (MPL) is studied in this paper. The focus is first on the actuators' controllers in the arm and a design technique is developed to reduce the maintenance costs as well as the cost of the arm's supervisor module without compromising its reliability. This technique can also be used as an analysis tool. Another contribution of this paper is related to motor redundancy. It is shown (using Petri Nets) how to increase their lifetime while reducing the cost of the added redundancy.

This paper documents a study of a wireless architecture for the Johns Hopkins modular prosthetic limb and it also presents a novel scheme to enhance the architecture’s reliability. Nowadays, the advanced prosthetic limbs, which are based on NCSs (Network Control Systems), are wired systems which are subjected to the wear and tear problem as well as the mobility limitation issue. Therefore, wired models can be replaced by Wireless Body Area Networks (WBANs) which can offer the same function and prevent the wear and tear and mobility problem. Moreover, medical applications such as the prosthetic arms are critical, real time and life-saving applications that require high reliability as faults in such systems can cause severe consequences. The well-known Modular Prosthetic Limb (MPL) designed by Johns Hopkins applied physics laboratory is revisited as it is the base of this study. The wireless architecture of the Johns Hopkins arm is simulated using RIVERBED. In addition, a fault-tolerant model for the same architecture is also simulated. Both, the fault free and faulty scenarios undergo interference analysis as well as a 95% confidence analysis. The simulation results have shown zero packet loss and the end-to-end delays are within the required range; hence, the system requirements are satisfied.

This paper focuses on FPGA-based systems in the context of space applications and nuclear plants which are extremely harsh environments. In such environments, the probability of occurrence of Multiple Event Upsets (MEUs) is not negligible. Conventional fault-tolerant architectures (such as Triple Modular Redundancy) will NOT be able to handle Triple Event Upsets (TEUs) for example. A fault-tolerant architecture with only six identical modules is developed in this paper even though, intuitively, at least seven modules are required for a system to recover from a TEU. It is proven that the proposed architecture can fully recover from any sequence of Single, Double or Triple Event Upsets by using Dynamic Partial Reconfiguration. If a hard fault affects one of the modules, the architecture will lose some of its fault tolerance but may be able to continue operating correctly depending on the nature of the next fault.

This paper proposes a system for intelligent energy management in electric vehicles. This system incorporates parameters relating to driving style of the car, trip information and battery states. The driving cycle classification subsystem is implemented in different scenarios, and the results of power, performance and utilization are reported. Finally, a performability analysis, utilizing the implementation scenarios for increasing the system reliability, is presented.

Fault tolerance is becoming an essential feature in today's Networked Control Systems (NCSs). The extra cost of redundancy is expected to be compensated by the reduced downtime. Especially in developing countries, large variations in duration of repair can greatly influence downtime. This paper studies the fault-tolerant aspect of an Ethernet-based NCS for pharmaceutical tablet production described in the literature. Markov models are used to calculate the steady state availability. A cost analysis is then conducted to relate availability, cost of downtime, inventory costs and cost of repair strategies. The techniques described in this paper are general and can be applied to different fault-tolerant NCSs.

Vehicle-to-Everything (V2X) technology plays a critical role in maintaining road safety, avoiding accidents and controlling traffic flow. As self driving cars are expected to take over the roads, this paper discusses the intermediate phase in which manned and unmanned cars coexist. A heterogeneous network architecture that simultaneously serves manned and unmanned cars' different requirements in a suburban area is proposed and simulated using Riverbed Modeler. The feasibility of this architecture is examined in three different scenarios: Normal operation, congestion in both directions and Road Side Units (RSU) failure. In normal operation mode, traffic data is sent through Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure/Infrastructure-to-Vehicle (V2I/I2V or to RSU) using IEEE 802.11p and infotainment information is communicated as V2I/I2V using Long Term Evolution (LTE). A special case is highlighted and tested, in which congestion is in both directions. In such situation, data needs to be relayed to the nearest RSU using multi-hop communication. A fault-tolerant model is also proposed and analyzed in case of failure of RSU. The performance metrics are end-to-end delay, LTE response time, handover delay and packet loss ratio. The architecture proves its suitability by satisfying traffic control real time application requirements.

Fault-Tolerance is currently a very important feature in industrial automation. This paper focuses on Fault-Tolerant FPGA-based controllers for Sensor-to-Actuator Networked Control Systems. A design is proposed that takes advantage of the Dynamic Partial Reconfiguration property inherent in some FPGAs. The controller is assumed to consist of a small processor, memory and associated hardware. Several Fault-Tolerance techniques are applied to this generic system and single points of failure are avoided even in the error detection and recovery mechanisms. The fault model considered is single and/or some multiple event upsets. A case study is presented to quantify the increase in reliability of the presented system. Furthermore, the proposed architecture can support FPGA full configuration as well as partial reconfiguration over TCP/IP networks through on-chip configuration network interface with minimal off-chip components.

Fault-tolerance is becoming an essential feature in the design of Networked Control Systems (NCSs). Furthermore, Sensor-to-Actuator (S2A) architectures have shown some advantages over conventional In-Loop architectures. This paper focuses on fault-tolerant controllers in the context of S2A systems. It proposes the use of Triple Modular Redundancy at the controller level. The fault-tolerant controller will be hosted in an FPGA that has a spare location. The voter in this TMR scheme is fault-secure to guarantee that the controllers never produce an undetected incorrect control action. Finally, system reliability is calculated using Markov models to quantitatively show, via case studies, the advantage of the proposed technique in terms of extended lifetime.

Fault-tolerance is becoming an increasingly crucial aspect of the design of Networked Control Systems (NCSs) in order to mitigate system downtime. However, the introduction of fault-tolerance is typically associated with significant traffic overhead. In this paper, an optimization to an Ethernet-based network fabric fault-tolerant NCS is proposed. The proposed optimization halves the amount of overhead traffic necessary for fault-tolerance while maintaining the same level of robustness. Moreover, based on the same optimization methodology, an expanded model with two in-line cells is presented and subsequently tested. The expanded two-cell model is designed to provide controller-level in addition to fabric-level fault-tolerance. Simulations using OPNET followed the traffic analysis, and proved the models to be fully reliable in the case of a single failure at a time, for both the single-cell model and the expanded two-cell network.

In this paper, the performance of an expanded controller level (1-out-of-3) fault-tolerant Wireless Networked Control System is studied. The system is composed of three identical workcells with zero meter inter-cell separation and is based on the unmodified IEEE 802.11b Wi-Fi standard. The control system is shown to satisfy certain packet end-to-end delay deadline with no loss of control packets. The interference tolerance of the system is then quantified and ongoing performance optimizations are investigated to improve system interference resilience. All simulations were conducted on OPNET Network Modeler and all subsequent results are subjected to a 95% confidence analysis.

Applying multiple redundant and diverse communication channels is an established method to achieve an improved overall communication channel. When applied for packet-based data transmission over channels with strongly nondeterministic behaviour due to environmental influence, such as Wireless Communications, timing performance can be greatly improved by this approach. The central element in such a system is the so called “Combiner” on the receiving side. In this work, a new specific type named “Timing Combiner” is described. The Parallel Redundancy Protocol (PRP) according to IEC 62439-3 realizes such a Timing Combiner on the Ethernet level. In this work, an OPNET simulation model is created and analysed for its performance characteristics. Also a quantitative analysis of the effect of different interference models in an industrial environment is presented.

Networked Control Systems (NCS) are widely used in industrial applications. Ethernet has recently been used as the communication protocol in NCS. Since overcoming faults is crucial in control systems, fault-tolerance in NCS is being extensively investigated. This paper focuses on the fault-tolerance aspect of Ethernet-based NCS at the network fabric level. It proposes a novel architecture that achieves successful recovery from any single link or switch failure. The model was also tested and proved to be fault-tolerant for some multiple failures.

This paper studies a Wireless Networked Control System based on IEEE's 802.11b Wi-Fi standard protocol consisting of two identical workcells with zero meter inter-cell distance. It is first shown how to improve system performance and increase the amount of noise that the system can tolerate without violating delay requirements or dropping control packets. Different noise models were studied. It was proved that increasing the short retry threshold increases system tolerance to noise. It was then shown through OPNET simulations that the two cell model is fault-tolerant at the controller level when either unicasting or multicasting is used. However, for the system to operate correctly in the presence of noise, multicasting had to be used.

In this study, OPNET simulations are run to study the performance of a single Gigabit Ethernet two-wagon train control network. The network carries both control and entertainment loads. Each wagon has two servers; a Controller to carry the control load and an Entertainment Server to carry the entertainment load. A passive supervisor is interconnected to both wagons. A fault tolerance analysis is presented; it is based on a specific reallocation of the control load. It is proven that the network can survive the failure of both Controllers and both Entertainment Servers. OPNET simulations indicated that the maximum real-time sensor-to-actuator packet end-to-end delay met its constraints and that there were zero packets dropped.

Wireless Sensor Networks (WSN) has become an attractive field for research due to the increasing number of applications. This paper uses a WSN to monitor Electromagnetic Pollution and report any violations in power levels. An event-by-event simulator is developed to calculate network lifetime and study important factors affecting it. One of these factors is determining the energy threshold of the Network Master. Different node distributions are investigated. It is found that the 10×10 star results in a 77% increase in lifetime in comparison with the Homogeneous Density distribution.

Wireless Networked Control Systems is becoming an important topic in the context of factory automation. In this paper, a workcell is studied where the 802.11 standard is used as the communication protocol. The focus is on the effect of different types of motion on the packet end-to-end delay. OPNET simulations indicate that motion does not violate the delay requirements for the proposed model. Since noise in the ISM band can affect wireless communication in the cell, the maximum permissible WiFi noise is found.

In this paper, a performability model is developed to analyze the effect of Access Point failures on the performance of a WiFi communication system. The system consists of seven Access Points in which mobile nodes (vehicles) travel at speeds up to 60 Km/hr. Traffic information is continuously sent by the infrastructure to the vehicles (I2V) in the form of bursts of identical packets to decrease packet loss. The model is based on a continuous time Markov chain used to obtain the steady state probabilities of each state. A penalty is then calculated for each state. This penalty takes into account the number of bursts lost, the number of consecutive bursts lost, vehicle speed and the specific location within the network where these losses occur.

In this paper, the repair process for fault-tolerant industrial production lines is investigated. The type of failure may significantly affect the repair time because of travel time, customs,... A modified Markov model is developed that takes into account these different repair times. The availability of a two-machine production line is then calculated using this model and is compared to the availability obtained from conventional models for the same production line. A case study shows that the results from the two models may vary significantly indicating that a more accurate description of the repair process was indeed necessary.

In this paper, a pyramid control hierarchy is proposed. It is based on the presence of a supervisor controller on top of separate controller nodes. A simulation study is conducted to test the functionality of the system. The proposed model is an enhancement of machine modeled in form of networked control systems (NCS). Two models are tested: one supervisor/two sub-controllers, one supervisor/three sub-controllers. All possible combinations of supervisor-controller intercommunication are tested. Also, all supervisor/controller inter-changeability possibilities are taken into consideration. Results are illustrated and discussed. Recommendations are drawn out. All machine models of this study are built using switched gigabit Ethernet in star topology