Multi-Sensor Based Online Attitude Estimation and Stability Measurement of Articulated Heavy Vehicles.

Articulated wheel loaders used in the construction industry are heavy vehicles and have poor stability and a high rate of accidents because of the unpredictable changes of their body posture, mass and centroid position in complex operation environments. This paper presents a novel distributed multi-sensor system for real-time attitude estimation and stability measurement of articulated wheel loaders to improve their safety and stability. Four attitude and heading reference systems (AHRS) are constructed using micro-electro-mechanical system (MEMS) sensors, and installed on the front body, rear body, rear axis and boom of an articulated wheel loader to detect its attitude. A complementary filtering algorithm is deployed for sensor data fusion in the system so that steady state margin angle (SSMA) can be measured in real time and used as the judge index of rollover stability. Experiments are conducted on a prototype wheel loader, and results show that the proposed multi-sensor system is able to detect potential unstable states of an articulated wheel loader in real-time and with high accuracy

Using gyro stabilizer for active anti-rollover control of articulated wheeled loader vehicles

Articulated wheeled loader vehicles have frequent rollover accidents as they operate in the complex outdoor environments. This article proposes an active anti-rollover control method based on a set of single-frame control moment gyro stabilizer installed on the rear body of the vehicle. The rollover dynamic model is first established for articulated wheeled loader vehicle with gyro stabilizer. The proposed control strategy is then applied in simulation to verify the rollover control effect on the vehicle under steady-state circumferential conditions. Finally, a home-built articulated wheel loader vehicle with gyro stabilizer is used to further verify the proposed control strategy. The results show that the vehicle can quickly return to the stable driving state and effectively avoid the vehicle rollover when a suitable anti-roll control moment can be provided by the gyro stabilizer. As a result, the articulated wheeled loader vehicle is able to operate safely in a complex outdoor environment

A novel data-driven rollover risk assessment for articulated steering vehicles using RNN

Articulated steering vehicles have outstanding capability operating but suffer from frequent rollover accidents due to their complicated structure. It is necessary to accurately detect their rollover risk for drivers to take action in time. Their variable structure and the variable center of mass exhibit nonlinear time-variant behavior and increase the difficulty of dynamic modelling and lateral stability description. This paper proposes a novel data-driven modelling methodology for lateral stability description of articulated steering vehicles. The running data is first collected based on the typical operations that prone to rollover and then classified into two types: Safety and danger. The data quality is further improved by wavelet transformation. Finally, an RNN model is built on the data. The experimental results show that the output of the RNN model can accurately quantify lateral stability of the vehicle, i.e., the risk of rollover, when it is turning and crossing uneven surfaces or obstacles

Advances in Automated Driving Systems

Electrification, automation of vehicle control, digitalization and new mobility are the mega-trends in automotive engineering, and they are strongly connected. While many demonstrations for highly automated vehicles have been made worldwide, many challenges remain in bringing automated vehicles to the market for private and commercial use. The main challenges are as follows: reliable machine perception; accepted standards for vehicle-type approval and homologation; verification and validation of the functional safety, especially at SAE level 3+ systems; legal and ethical implications; acceptance of vehicle automation by occupants and society; interaction between automated and human-controlled vehicles in mixed traffic; human–machine interaction and usability; manipulation, misuse and cyber-security; the system costs of hard- and software and development efforts. This Special Issue was prepared in the years 2021 and 2022 and includes 15 papers with original research related to recent advances in the aforementioned challenges. The topics of this Special Issue cover: Machine perception for SAE L3+ driving automation; Trajectory planning and decision-making in complex traffic situations; X-by-Wire system components; Verification and validation of SAE L3+ systems; Misuse, manipulation and cybersecurity; Human–machine interactions, driver monitoring and driver-intention recognition; Road infrastructure measures for the introduction of SAE L3+ systems; Solutions for interactions between human- and machine-controlled vehicles in mixed traffic

Towards Automation and Improved Fuel Economy with System Architecture Design of a Non-Road Working Machine

Increasing levels of automation and interest in fuel economy have been affecting the system design of non-road working machines. Both fuel economy and automation have been active research areas in non-road working machines. It is unlikely that in the near future electrification will solve the energy challenges of machines operating for long periods in forests, mines or fields. Therefore, it is necessary to increase the fuel efficiency of such machines with conventional technology, taking into account the fact that automation, along with the diversity of subcontractors and performance requirements, has increased the complexity of these machines. A modular abstraction layer architecture is proposed for the machine level to support the development of automation and comparison of fuel economy. The architecture is developed and selected on the premise that a machine is operated with different automation levels between manual and autonomous operation and employs alternative control methods for different operation conditions. The designed system architecture is compared with alternative approaches by using trade-off analysis with defined scoring functions. For improving fuel economy and demonstrating the capability of the designed architecture, a modular power management architecture is realised to meet the performance requirements of the machine. This architecture breaks the system down into smaller modules to facilitate design and development. Further, the architecture separates control of the power sources from the consumers, providing a new degree of freedom in designing the subsystems, as the consumer modules are not coupled with the engine. The improvement in fuel economy is based on the MinRpm control strategy, which is integrated with the power management architecture. The objective of MinRpm is to minimise the rotational speed of the engine, which leads to the engine operating with higher partial loads and in a higher fuel efficiency region. In addition, the components and subsystems that use relative constant torque use less energy when the rotational speed is lower. Devices of this kind are typically fans, fixed displacement pumps and oil coolers, in which the torque demand is not highly dependent on the rotational speed of the engine. The proposed modular power management architecture with the MinRpm control strategy does not require any new components to make improvements in fuel economy, which, in turn, reduces the implementation costs. In both simulations and in experimental tests with a municipal wheel loader, the control method resulted in fuel savings of 11 to 22% compared with a series-production machine on the market. The comparison is realised by integrating the emulated series-production machine control with the same system architecture that was developed for the power management system with MinRpm approach. Therefore, both control methods are realised with the same wheel loader, which eliminates discrepancy of the component properties. Realisation of the alternative control methods in the designed system architecture demonstrates the compatibility needed when the machine is operated with different operating modes from manual to autonomous. Before fully autonomous machines become real, a different level of automation is needed to perform efficiently and safely in all operation conditions. Therefore, the designed system architecture is capable of rerouting control signals and control flows, while safety features are guaranteed when the control mode is changed

Piloted aircraft simulation concepts and overview

An overview of piloted aircraft simulation is presented that reflects the viewpoint of an aeronautical technologist. The intent is to acquaint potential users with some of the basic concepts and issues that characterize piloted simulation. Application to the development of aircraft are highlighted, but some aspects of training simulators are covered. A historical review is given together with a description of some current simulators. Simulator usages, advantages, and limitations are discussed and human perception qualities important to simulation are related. An assessment of current simulation is presented that addresses validity, fidelity, and deficiencies. Future prospects are discussed and technology projections are made

High-Level Job Planning for Automated Earthmoving

High-level job planning strategies were developed which enable pile transfer and area clearing jobs to be performed autonomously by a robotic wheel loader. A job is first planned on a 3D surface model of a worksite by positioning graphical tools representing areas and approach directions for scooping, dumping and clearing material. The ground model can be from a recently-acquired surface scan, allowing the job to be configured ad-hoc without the prior need of a global map. Algorithms interpret the high-level plan and, based on an updated ground model, generate commands which ideally guide the job to completion with no further human input. Lower-level plans such as driving points are also represented graphically, allowing a remote supervisor to stay in-the-loop by monitoring the intentions of the machine and modifying the plans if necessary. Fully automated jobs were demonstrated in an earthmoving simulation environment developed using Matlab. The algorithms and search parameters for finding clearing paths and filling locations which worked in the simulator were also found to correctly generate commands using ground models obtained from manually-performed area clearing and filling tests using snow and gravel. As proofs-of-concept, a snow clearing test and two pile transfer tests with gravel demonstrated semi-automated work cycles with a robotic loader, whereby driving and joint actuation were computer-controlled, with transitions between separate actions commanded manually. The snow clearing test demonstrated updated paths being generated based on the changing state of the worksite. The planning tools and algorithms were also extended to jobs including dump trucks and multiple loaders, and applied to a large-scale simulated hillside excavation. Additional simulations evaluated the proposed alternative High Point (HP) method for generating scooping commands, which orients the loader towards the highest point in the pile or slope section from an adjacent stage point. This was compared with a Zero Contour (ZC) method which selects perpendicular scooping approaches along the bottom contour of the slope. Various excavation jobs with truck loading showed that assuming the same bucket filling efficiency, the HP method offers the advantage of a higher excavation rate due to its more limited driving pattern. For the larger plateau excavation jobs, the workspace was subdivided by scanning with the smaller rectangular Scoop Area (SA). It was found that compared with the ZC method, the HP method tends to achieve its maximum excavation rate with SAs which are narrower and longer. Factors which increased the amount of material to excavate per area, including a higher plateau and more surrounding slope collapse, were found to generally result in smaller SAs achieving higher excavation rates

The cetaceopteryx: A global range military transport aircraft

This paper presents a design of a military transport aircraft capable of carrying 800,000 lbs of payload from any point in the United States to any other point in the world. Such massive airlift requires aggressive use of advanced technology and a unique configuration. The Cetaceopteyx features a joined wing, canard and six turbofan engines. The aircraft has a cost 1.07 billion (1993) dollars each. This paper presents in detail the mission description, preliminary sizing, aircraft configuration, wing design, fuselage design, empennage design, propulsion system, landing gear design, structures, drag, stability and control, systems layout, and cost analysis of the aircraft

Piloted Simulator Evaluation Results of Flight Physics Based Stall Recovery Guidance

In recent studies, it has been observed that loss of control in flight is the most frequent primary cause of accidents. A significant share of accidents in this category can be remedied by upset prevention if possible, and by upset recovery if necessary, in this order of priorities. One of the most important upsets to be recovered from is stall. Recent accidents have shown that a correct stall recovery maneuver remains a big challenge in civil aviation, partly due to a lack of pilot training. A possible strategy to support the flight crew in this demanding context is calculating a recovery guidance signal, and showing this signal in an intuitive way on one of the cockpit displays, for example by means of the flight director. Different methods for calculating the recovery signal, one based on fast model predictive control and another using an energy based approach, have been evaluated in four relevant operational scenarios by experienced commercial as well as test pilots in the Vertical Motion Simulator at NASA Ames Research Center. Evaluation results show that this approach could be able to assist the pilots in executing a correct stall recovery maneuver