Accidental collisions involving wheeled industrial ground vehicles can be costly to repair, cause serious (even fatal) human injury, and lead to setbacks with tight operation schedules. Reduction of vehicle collisions carries numerous safety and financial incentives. In this work, an integrated collision avoidance package is developed to reduce the number of vehicle collisions. Utilizing feedback from on-board sensing devices, a model predictive control (MPC) algorithm predicts control options and paths, then disallows drivers to accelerate and/or induces braking of the vehicle if a collision is imminent. A prototype system is developed, implemented, and tested on an industrial vehicle to mitigate collisions with people and high-value equipment. Testing results show that control can be executed in real time by the proposed system, and that the proposed method is effective in preventing an industrial vehicle from hitting detected obstacles and entering restricted areas.

Rear-end collisions in which the leading vehicle was stationary prior to impact and at least one vehicle was towed from the crash site represent 18% of all yearly crashes in the United States. Forward Collision Avoidance Systems (FCASs) are becoming increasingly available in production vehicles and have a great potential for preventing or mitigating rear-end collisions. The objective of this study was to compare the effectiveness of five crash avoidance algorithms that are similar in design to systems found on production vehicles of model year 2011. To predict the effectiveness of each algorithm, this study simulated a representative sample of rear-end collisions as if the striking vehicle was equipped with each FCAS. In 2011, the ADAC (Allgemeiner Deutscher Automobil-Club e.V) published a test report comparing advanced emergency braking systems. The ADAC tested production vehicles of model year 2011 made by Audi, BMW, Infiniti, Volvo, and VW. The ADAC test results were used in conjunction with video evidence and owner's manual information to develop mathematical models of five different FCASs. The systems had combinations of Forward Collision Warning (FCW), Assisted Braking (AB), and Autonomous Emergency Braking (AEB). The effectiveness of each modeled system was measured by its ability to prevent collisions or reduce the collision severity of reconstructed crashes. In this study, 977 rear-end crashes that occurred from 1993 to 2008 were mathematically reconstructed. These crashes were investigated as part of NHTSA's National Automotive Sampling System, Crashworthiness Data System (NASS/CDS). These crashes represent almost 800,000 crashes during that time period in which the struck vehicle was stationary. Part of the NASS/CDS investigation was to reconstruct the vehicle change in velocity during impact, ∆V. Using energy and Newtonian based methods, the ∆V in each crash was calculated as if the vehicle was equipped with each modeled FCAS. Using the predicted reduction in crash ∆V, the expected reduction in the number of moderately-to-fatally injured (MAIS2+) drivers was predicted. This study estimates that the most effective FCAS model was the Volvo algorithm which could potentially prevent between 79% and 92% of the crashes simulated in this study and between 76% and 94% of associated driver injuries. This study estimates that the BMW algorithm would prevent the fewest number of crashes (between 11% and 14%), but would provide admirable benefits to driver safety by preventing between 21% and 25% of driver injuries. The VW algorithm would be the least effective at preventing driver injuries if the system were to be implemented across the U.S. fleet. This algorithm offers a 19% reduction in crashes, but only prevents 15% of driver injuries. This study introduces and demonstrates a unique method of comparing potential benefits of competing FCAS algorithms. This method could be particularly useful to system designers for comparing the expected effects of design decisions on safety performance. This method could also be useful to government officials who wish to evaluate the effectiveness of FCASs. / Master of Science

京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第22784号 / 農博第2427号 / 新制||農||1081(附属図書館) / 学位論文||R2||N5304(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 飯田 訓久, 教授 近藤 直, 教授 中嶋 洋 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM

Robotic automation has evolved to be an irreplaceable part of production lines. Orderly operation of the robots is a key factor. Yet robots often have to deal with unpredictable factors including human beings or possible failures that lead to unexpected behaviours. Collision avoidance mechanisms are therefore of outmost importance to prevent injuries and damage. A major challenge in the creation of a dependable collision avoidance system is the sensory system that could cover relevant parts of the robot and capacitive sensors are a promising solution. The burden is to overcome the nonlinearity and other limitations of the capacitive sensors and harness their potential to this end. It is cumbersome to estimate the proximity of surfaces of the robot from its environment (which could include other robots) from the capacitive readings, so a novel sensing approach is proposed in this thesis. For industrial applications where the motions are well-defined, a pre-recorded capacitive signature can be used to monitor for unexpected changes. In this thesis the capacitive signature of one or more robotic arms will be used to predict and prevent collisions in a robotic workcell. A short training cycle is used to create a signature that is used at runtime to monitor the robot operation. Capacitive electrodes are placed on strategic locations on the robot arms and the surrounding environments and a supervisor computer uses the readings to cease the operation in case of any abnormality. This thesis describes the details of generating the signature from the training data and the runtime software. The supervisor computer provides a pause and/or go signal to the robot(s). The native controller of each arm is kept in place and the only change needed is the ability of each controller to pause the arm at command when a collision is detected and continue from this paused state. This approach requires minimum changes to the existing robotic equipments and programmes. These hardware requirements are widely available on existing controllers. Signature creation is the process of finding the normal pattern of the capacitance readings from all sensors as well as some expected limits allowing for the variations that are to be expected. The algorithms, reasoning, and experimental data are provided throughout the text. The system is tested on a robotic workcell that includes an actively controlled robot and a passive revolute joint. While the algorithm is universal, the suggested hardware has been shown to provide sampling times of down to 20ms, and positional accuracies of ±2mm or better are achieved for the test setup. The thesis also proposes methods to expand the measurement hardware for increased protection and fault tolerance. / Thesis / Master of Applied Science (MASc)

Active safety systems that warn automobile drivers of various types of impending collisions have been developed. How these systems alert drivers when integrated, however, is a crucial component to their effectiveness that hinges on the consideration of human factors. Drivers' ability to comprehend multiple alerts presented through a haptic driver seat was investigated in this dissertation. Twenty-four participants, balanced for age and gender, drove an instrumented vehicle on a test-track while haptic alerts (vibrations in the driver seat) were generated. Drivers' ability to transmit the information conveyed by the alerts was investigated through two experiments. The first experiment investigated the effects of increasing the number of potential alerts on drivers' response performance. The second experiment investigated whether presenting haptic alerts through unique versus common locations in the driver seat affects drivers' response performance. Younger drivers (between the ages of 18 and 25 years old) were found to efficiently process the increased information contained in the alerts, while older drivers were not as efficient. However, it is foreseeable that older driver performance decrements may be assuaged when a crash context is provided. A third experiment evaluated the haptic driver seat's ability to alert distracted drivers to an actual crash threat. Drivers that received a haptic seat alert returned their gaze to the forward roadway sooner, removed their foot from the throttle sooner, pressed the brake pedal sooner, and stopped farther away from an inflatable barricade than drivers that did not receive a haptic seat alert. No age or gender effects were found in this experiment. Furthermore, half of the drivers that received the haptic seat alert lifted up on the throttle before returning their eyes to the forward roadway. This suggests these drivers developed an automatic response to the haptic seat alerts through their experience with the previous two experiments. A three-alert haptic seat approach, the intermediate alternative tested, is recommended providing specific design requirements are met. / Ph. D.

Thesis submitted in compliance with the requirements of the Master's Degree in Technology: Mechanical Engineering, Durban University of Technology, 2009. / Automotive bumpers are installed primarily to minimize damage and harm to both the automobile and passengers during minor and low speed collisions. The efficacy of the current bumper systems lies in absorbing the impact energy. The primary mechanism for energy absorption is damage. In this study an attempt is made to shift from this traditional design platform by exploring non-destructive energy dissipation mechanisms. In pursuit of this, an alternative bumper system that simulates human-arm ergonomic response to impact has been proposed. The system capitalizes on the characteristic dissipative mechanics of granular media. A mathematical model describing the dissipative mechanics of the system is presented. The model shows that granular media can be used effectively to re-direct the impulse wave away from its axis of incidence. The resulting effect is that the impulse wave is attenuated through the thickness. A second mathematical model, based on the Concept of Energy Balance has been developed. Here, the total impact energy is shown to be absorbed or dissipated by the individual components of the system. The largest component of this energy is taken up by sliding and rotation of the granular media. Both models are validated by experimentation. A prototype system has been built and tested. The system effectively manages impact energy with minimal or no damage to the constituent components. The system demonstrates an ability to recover dimensionally when loaded under FMVSS conditions. / Post Graduate Development Support

This thesis investigates the problem of sensors used with mobile robots. Firstly, a colour sensor is considered, for its ability to detect objects having the three primary colours Red, Green and Blue (RGB). Secondly, an accelerometer was investigated, from which velocity was derived from the raw data using numerical integration. The purpose of the design and development of the sensors was to use them for robotic navigation and collision avoidance. This report presents the results of experiments carried out on the colour sensor and the accelerometer. A discussion of the results and some conclusions are also presented. It proved feasible to achieve the goal of detecting colours successfully but only for a limited distance. The accelerometer proved reliable but is not yet being applied in real time. Both the colour sensor and the accelerometer proved to be inexpensive. Some recommendations are made to improve both the colour sensor and the accelerometer sensors.

By the year 2020 the number of aircraft will have increased substantially and will be in �Free Flight�(that is, ATC will be devolved to the aircraft rather than being ground based). As an aid to navigation a more advanced form of collision avoidance will be required. This thesis proposes a method of collision avoidance planning using Automatic Dependent Surveillance-Broadcast (ADS-B) and Dynamic Programming (DP). It in essence enables Air Traffic Control (ATC) from within the cockpit for remote or uncontrolled airspace and is a step toward Free Flight. Free Flight requires quite different strategies than those used in the present collision avoidance schemes. This thesis reviews the approaches to collision avoidance used in the Air traffic navigation and to similar problems in other industries. In particular it considers the extended problem of collision avoidance within the framework of path planning. This is a key departure from the approach to aircraft collision avoidance used in the industry to date. Path planning reflects the real goal of an aircraft, which is to reach a particular destination efficiently and safely. Dynamic Programming is one solution method used in other industries for the problem of path planning to avoid collisions with fixed obstacles. The solution proposed herein for the Aircraft case uses Dynamic Programming applied to the moving obstacle case. The problem is first simplified by assuming fixed (static) obstacles for the cost minimisation algorithms. These fixed obstacles are then moved with time and the minimisation process is repeated at each time increment. Although this method works well in most cases, situations can be constructed where this method fails, allowing a collision. A modified approach is then used, whereby the movement of obstacles is included more explicitly (by modifying the shapes of the obstacles to represent motion) in the cost minimisation algorithm and a safe manoeuvre distance for each aircraft is used (by expanding the object size), to allow space for aircraft to execute safe evasive manoeuvres in difficult cases. This modification allows solutions which are complete (with no known cases of failure � collision situations) and should be considered as an important extension to the current Aircraft and Collision Avoidance System (ACAS). The testing of these solutions is focussed on the most difficult cases, and includes aircraft movement in �real space� (that is simulations using real aircraft dynamics together with dynamic programming algorithms running in discrete time steps).

We consider the problem of moving a three dimensional solid object among polyhedral obstacles. The traditional formulation of configuration space for this problem uses three translational parameters and three angles (typically Euler angles), and the constraints between the object and obstacles involve transcendental functions. We show that a quaternion representation of rotation yields constraints which are purely algebraic in a higher-dimensional space. By simple manipulation, the constraints may be projected down into a six dimensional space with no increase in complexity. Using this formulation, we derive an efficient exact intersection test for an object which is translating and rotating among obstacles.

Free space is represented as a union of (possibly overlapping) generalized cones. An algorithm is presented which efficiently finds good collision free paths for convex polygonal bodies through space littered with obstacle polygons. The paths are good in the sense that the distance of closest approach to an obstacle over the path is usually far from minimal over the class of topologically equivalent collision free paths. The algorithm is based on characterizing the volume swept by a body as it is translated and rotated as a generalized cone and determining under what conditions generalized cone is a subset of another.